Inter- and Intrasubject Similarity of Muscle Synergies During Bench Press With Slow and Fast Velocity.

Science.gov (United States)

Samani, Afshin; Kristiansen, Mathias

2018-01-01

We investigated the effect of low and high bar velocity on inter- and intrasubject similarity of muscle synergies during bench press. A total of 13 trained male subjects underwent two exercise conditions: a slow- and a fast-velocity bench press. Surface electromyography was recorded from 13 muscles, and muscle synergies were extracted using a nonnegative matrix factorization algorithm. The intrasubject similarity across conditions and intersubject similarity within conditions were computed for muscle synergy vectors and activation coefficients. Two muscle synergies were sufficient to describe the dataset variability. For the second synergy activation coefficient, the intersubject similarity within the fast-velocity condition was greater than the intrasubject similarity of the activation coefficient across the conditions. An opposite pattern was observed for the first muscle synergy vector. We concluded that the activation coefficients are robust within conditions, indicating a robust temporal pattern of muscular activity across individuals, but the muscle synergy vector seemed to be individually assigned.

Slow-light pulses in moving media

International Nuclear Information System (INIS)

Fiurasek, J.; Leonhardt, U.; Parentani, R.

2002-01-01

Slow light in moving media reaches a counterintuitive regime when the flow speed of the medium approaches the group velocity of light. Pulses can penetrate a region where a counterpropagating flow exceeds the group velocity. When the counterflow slows down, pulses are reflected

Timely Referral to Outpatient Nephrology Care Slows Progression and Reduces Treatment Costs of Chronic Kidney Diseases

Directory of Open Access Journals (Sweden)

Gerhard Lonnemann

2017-03-01

Discussion: Timely referral to outpatient nephrology care is associated with slowed disease progression, less hospital admissions, reduced total treatment costs, and improved survival in patients with CKD.

Theoretical Research Progress in High-Velocity/Hypervelocity Impact on Semi-Infinite Targets

Directory of Open Access Journals (Sweden)

Yunhou Sun

2015-01-01

Full Text Available With the hypervelocity kinetic weapon and hypersonic cruise missiles research projects being carried out, the damage mechanism for high-velocity/hypervelocity projectile impact on semi-infinite targets has become the research keystone in impact dynamics. Theoretical research progress in high-velocity/hypervelocity impact on semi-infinite targets was reviewed in this paper. The evaluation methods for critical velocity of high-velocity and hypervelocity impact were summarized. The crater shape, crater scaling laws and empirical formulae, and simplified analysis models of crater parameters for spherical projectiles impact on semi-infinite targets were reviewed, so were the long rod penetration state differentiation, penetration depth calculation models for the semifluid, and deformed long rod projectiles. Finally, some research proposals were given for further study.

Slow-light dynamics in nonlinear periodic waveguides couplers

DEFF Research Database (Denmark)

Sukhorukov, A.A.; Ha, S.; Powell, D.A.

2009-01-01

We predict pulse switching and reshaping through nonlinear mixing of two slow-light states with different phase velocities in the same frequency range, and report on the first experimental observation of slow-light tunneling between coupled periodic waveguides.......We predict pulse switching and reshaping through nonlinear mixing of two slow-light states with different phase velocities in the same frequency range, and report on the first experimental observation of slow-light tunneling between coupled periodic waveguides....

Effects of instability versus traditional resistance training on strength, power and velocity in untrained men.

Science.gov (United States)

Maté-Muñoz, José Luis; Monroy, Antonio J Antón; Jodra Jiménez, Pablo; Garnacho-Castaño, Manuel V

2014-09-01

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p velocity and jumping ability. Key PointsSimilar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs.Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training.RPE emerged as a useful tool to monitor exercise intensity during instability strength training.

Electrom emission from slow highly charged ions interacting with a metal surface

International Nuclear Information System (INIS)

Aumayr, F.; Kurz, H.; Toeglhofer, K.; Winter, H.

1992-01-01

Recent progress in investigating electron emission from slow highly charged ions approaching a metal surface is discussed. In particular, new informations on generation and decay of transient multiply excited ''hollow atoms'' developing during these processes have been gained from measurement of the statistics of emitted electrons (ES). ES and precise total electron yields derived from the former have been measured for normal incidence of slow (impact velocity 1/15.10 4 ms -1 ) multicharged ions N q+ (q≤6), Ne q+ (q≤10), Ar q+ (q≤16), Kr q+ (q≤10), Xe q+ (q≤10) and I q+ (q≤25) on clean polycrystalline gold. A classical over-barrier approach as recently introduced by Burgdoerfer et al. 1991 has been extended and successfully applied to model the measured impact-velocity dependences of total electron yields. In this way contributions from different electron emission mechanisms could be identified. (orig.)

Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract.

Science.gov (United States)

Mathew, Milan C; Ervin, Ann-Margret; Tao, Jeremiah; Davis, Richard M

2012-06-13

Age-related cataract is a major cause of visual impairment in the elderly. Oxidative stress has been implicated in its formation and progression. Antioxidant vitamin supplementation has been investigated in this context. To assess the effectiveness of antioxidant vitamin supplementation in preventing and slowing the progression of age-related cataract. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 2), MEDLINE (January 1950 to March 2012), EMBASE (January 1980 to March 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to March 2012), Open Grey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 2 March 2012. We also checked the reference lists of included studies and ongoing trials and contacted investigators to identify eligible randomized trials. We included only randomized controlled trials in which supplementation with one or more antioxidant vitamins (beta-carotene, vitamin C and vitamin E) in any form, dosage or combination for at least one year was compared to another antioxidant vitamin or to placebo. Two authors extracted data and assessed trial quality independently. We pooled results for the primary outcomes, i.e., incidence of cataract and incidence of cataract extraction. We did not pool results of the secondary outcomes - progression of cataract and loss of visual acuity, because of differences in definitions of outcomes and data presentation. We pooled results by type of cataract when data were available. We did not perform a sensitivity analysis. Nine trials involving 117

Relative differences in strength and power from slow to fast isokinetic velocities may reflect dynapenia.

Science.gov (United States)

Jenkins, Nathaniel D M; Housh, Terry J; Palmer, Ty B; Cochrane, Kristen C; Bergstrom, Haley C; Johnson, Glen O; Schmidt, Richard J; Cramer, Joel T

2015-07-01

We compared absolute and normalized values for peak torque (PT), mean power (MP), rate of velocity development, and electromyography (EMG) amplitude during maximal isometric and concentric isokinetic leg extension muscle actions, as well as the %decrease in PT and %increase in MP from 1.05 to 3.14 rad·s(-1) in younger versus older men. Measurements were performed twice for reliability. Isokinetic measurements were normalized to the isometric muscle actions. Absolute isometric PT, isokinetic PT and MP, and EMG amplitudes at 1.05 and 3.14 rad·s(-1) were greater in the younger men, although normalizing to isometric PT eliminated the age differences. The older men exhibited greater %decrease in PT (37.2% vs. 31.3%) and lower %increase in MP (87.6% vs. 126.4%) regardless of normalization. Normalization eliminated absolute differences in isokinetic strength and power, but the relative differences from slow to fast velocities may reflect dynapenia characterized by age-related decreases in fast-twitch fiber function. © 2014 Wiley Periodicals, Inc.

Slow rupture of frictional interfaces

Science.gov (United States)

Bar Sinai, Yohai; Brener, Efim A.; Bouchbinder, Eran

2012-02-01

The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not completely understood. We show that slow rupture is an intrinsic and robust property of simple non-monotonic rate-and-state friction laws. It is associated with a new velocity scale cmin, determined by the friction law, below which steady state rupture cannot propagate. We further show that rupture can occur in a continuum of states, spanning a wide range of velocities from cmin to elastic wave-speeds, and predict different properties for slow rupture and ordinary fast rupture. Our results are qualitatively consistent with recent high-resolution laboratory experiments and may provide a theoretical framework for understanding slow rupture phenomena along frictional interfaces.

A viscoplastic shear-zone model for episodic slow slip events in oceanic subduction zones

Science.gov (United States)

Yin, A.; Meng, L.

2016-12-01

Episodic slow slip events occur widely along oceanic subduction zones at the brittle-ductile transition depths ( 20-50 km). Although efforts have been devoted to unravel their mechanical origins, it remains unclear about the physical controls on the wide range of their recurrence intervals and slip durations. In this study we present a simple mechanical model that attempts to account for the observed temporal evolution of slow slip events. In our model we assume that slow slip events occur in a viscoplastic shear zone (i.e., Bingham material), which has an upper static and a lower dynamic plastic yield strength. We further assume that the hanging wall deformation is approximated as an elastic spring. We envision the shear zone to be initially locked during forward/landward motion but is subsequently unlocked when the elastic and gravity-induced stress exceeds the static yield strength of the shear zone. This leads to backward/trenchward motion damped by viscous shear-zone deformation. As the elastic spring progressively loosens, the hanging wall velocity evolves with time and the viscous shear stress eventually reaches the dynamic yield strength. This is followed by the termination of the trenchward motion when the elastic stress is balanced by the dynamic yield strength of the shear zone and the gravity. In order to account for the zig-saw slip-history pattern of typical repeated slow slip events, we assume that the shear zone progressively strengthens after each slow slip cycle, possibly caused by dilatancy as commonly assumed or by progressive fault healing through solution-transport mechanisms. We quantify our conceptual model by obtaining simple analytical solutions. Our model results suggest that the duration of the landward motion increases with the down-dip length and the static yield strength of the shear zone, but decreases with the ambient loading velocity and the elastic modulus of the hanging wall. The duration of the backward/trenchward motion depends

Slow wave cyclotron maser

International Nuclear Information System (INIS)

Kho, T.H.; Lin, A.T.

1988-01-01

Cyclotron masers such as Gyrotrons and the Autoresonance Masers, are fast wave devices: the electromagnetic wave's phase velocity v rho , is greater than the electron beam velocity, v b . To be able to convert the beam kinetic energy into radiation in these devices the beam must have an initial transverse momentum, usually obtained by propagating the beam through a transverse wiggler magnet, or along a nonuniform guide magnetic field before entry into the interaction region. Either process introduces a significant amount of thermal spread in the beam which degrades the performance of the maser. However, if the wave phase velocity v rho v b , the beam kinetic energy can be converted directly into radiation without the requirement of an initial transverse beam momentum, making a slow wave cyclotron maser a potentially simpler and more compact device. The authors present the linear and nonlinear physics of the slow wave cyclotron maser and examine its potential for practical application

Decision making in high-velocity environments: implications for healthcare.

Science.gov (United States)

Stepanovich, P L; Uhrig, J D

1999-01-01

Healthcare can be considered a high-velocity environment and, as such, can benefit from research conducted in other industries regarding strategic decision making. Strategic planning is not only relevant to firms in high-velocity environments, but is also important for high performance and survival. Specifically, decision-making speed seems to be instrumental in differentiating between high and low performers; fast decision makers outperform slow decision makers. This article outlines the differences between fast and slow decision makers, identifies five paralyses that can slow decision making in healthcare, and outlines the role of a planning department in circumventing these paralyses. Executives can use the proposed planning structure to improve both the speed and quality of strategic decisions. The structure uses planning facilitators to avoid the following five paralyses: 1. Analysis. Decision makers can no longer afford the luxury of lengthy, detailed analysis but must develop real-time systems that provide appropriate, timely information. 2. Alternatives. Many alternatives (beyond the traditional two or three) need to be considered and the alternatives must be evaluated simultaneously. 3. Group Think. Decision makers must avoid limited mind-sets and autocratic leadership styles by seeking out independent, knowledgeable counselors. 4. Process. Decision makers need to resolve conflicts through "consensus with qualification," as opposed to waiting for everyone to come on board. 5. Separation. Successful implementation requires a structured process that cuts across disciplines and levels.

The effects of slow- and fast-rhythm classical music on progressive cycling to voluntary physical exhaustion.

Science.gov (United States)

Szabo, A; Small, A; Leigh, M

1999-09-01

To investigate, based on the parallel information processing model and arousal hypothesis, whether musical tempo and its manipulation during exercise affect the maximal workload (watts) achieved during progressive cycling. repeated measures experiment that involved one control and four treatment conditions. the experiment was performed in a controlled laboratory environment. twenty-four male and female volunteers, recruited from among a University population, were tested. the data collection proceeded in five counterbalanced test-sessions that included control (C), slow music (SM), fast music (FM) slow to fast music (SFM) and fast to slow music (FSM) interventions. In the last two conditions, musical tempo was changed when the participant's maximal HR reserve has reached 70%. In all test-sessions, participants started to cycle at 50 watts and then the workload was increased in increments of 25 watts every minute until self-declared exhaustion. Maximal ergometer cycling was defined as the workload at the last completed minute of exercise. workload, HR, and postexperimental ratings of test-session preferences were the dependent measures. Significantly higher workload was accomplished in the SFM condition. No between-session differences were seen in HR. The results also yielded significantly better "efficiency", in terms of workload/HR reserve ratio, in the SFM session. PARTICIPANTS preferred the FM and SFM sessions more than the other sessions. Switching to FM during progressive exercise results in the accomplishment of more work without proportional changes in HR. These effects may be due to distraction from fatigue and are, apparently, dependent on the attention capturing strength of the distracting stimulus.

Slow light enhancement and limitations in periodic media

DEFF Research Database (Denmark)

Grgic, Jure

in the vicinity of the band edge. The minimum attainable group velocity will depend on the amount of imperfections. Since imperfections are inherited as part of any periodic structure it is necessary to take them into account when we are interested in slow light applications. Slowly propagating light gives rise......Properties of periodic dielectric media have attracted a big interest in the last two decades due to numerous exciting physical phenomena that cannot occur in homogeneous media. Due to their strong dispersive properties, the speed of light can be significantly slowed down in periodic structures....... When light velocity is much smaller than the speed of light in a vacuum, we describe this phenomena as slow light. In this thesis, we analyze important properties of slow light enhancement and limitations in periodic structures. We analyze quantitatively and qualitatively different technologies...

FORCE-VELOCITY, IMPULSE-MOMENTUM RELATIONSHIPS: IMPLICATIONS FOR EFFICACY OF PURPOSEFULLY SLOW RESISTANCE TRAINING

Directory of Open Access Journals (Sweden)

Brian K. Schilling

2008-06-01

Full Text Available The purpose of this brief review is to explain the mechanical relationship between impulse and momentum when resistance exercise is performed in a purposefully slow manner (PS. PS is recognized by ~10s concentric and ~4-10s eccentric actions. While several papers have reviewed the effects of PS, none has yet explained such resistance training in the context of the impulse-momentum relationship. A case study of normal versus PS back squats was also performed. An 85kg man performed both normal speed (3 sec eccentric action and maximal acceleration concentric action and PS back squats over a several loads. Normal speed back squats produced both greater peak and mean propulsive forces than PS action when measured across all loads. However, TUT was greatly increased in the PS condition, with values fourfold greater than maximal acceleration repetitions. The data and explanation herein point to superior forces produced by the neuromuscular system via traditional speed training indicating a superior modality for inducing neuromuscular adaptation

Numerical Simulations of Slow Stick Slip Events with PFC, a DEM Based Code

Science.gov (United States)

Ye, S. H.; Young, R. P.

2017-12-01

Nonvolcanic tremors around subduction zone have become a fascinating subject in seismology in recent years. Previous studies have shown that the nonvolcanic tremor beneath western Shikoku is composed of low frequency seismic waves overlapping each other. This finding provides direct link between tremor and slow earthquakes. Slow stick slip events are considered to be laboratory scaled slow earthquakes. Slow stick slip events are traditionally studied with direct shear or double direct shear experiment setup, in which the sliding velocity can be controlled to model a range of fast and slow stick slips. In this study, a PFC* model based on double direct shear is presented, with a central block clamped by two side blocks. The gauge layers between the central and side blocks are modelled as discrete fracture networks with smooth joint bonds between pairs of discrete elements. In addition, a second model is presented in this study. This model consists of a cylindrical sample subjected to triaxial stress. Similar to the previous model, a weak gauge layer at a 45 degrees is added into the sample, on which shear slipping is allowed. Several different simulations are conducted on this sample. While the confining stress is maintained at the same level in different simulations, the axial loading rate (displacement rate) varies. By varying the displacement rate, a range of slipping behaviour, from stick slip to slow stick slip are observed based on the stress-strain relationship. Currently, the stick slip and slow stick slip events are strictly observed based on the stress-strain relationship. In the future, we hope to monitor the displacement and velocity of the balls surrounding the gauge layer as a function of time, so as to generate a synthetic seismogram. This will allow us to extract seismic waveforms and potentially simulate the tremor-like waves found around subduction zones. *Particle flow code, a discrete element method based numerical simulation code developed by

Connecting slow earthquakes to huge earthquakes

OpenAIRE

Obara, Kazushige; Kato, Aitaro

2016-01-01

Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of th...

Post-ischemic azotemia as a partial 'brake', slowing progressive kidney disease.

Science.gov (United States)

Zager, Richard A; Johnson, Ali C; Becker, Kirsten

2013-06-01

Recent experimental work suggests a paradox: although uremia evokes systemic toxicities, in the setting of AKI, it can induce intrarenal cytoprotective and anti-inflammatory effects. Whether these influences can attenuate post-ischemic kidney disease progression remains unknown. To explore this possibility, male CD-1 mice were subjected to a 30-min unilateral (left) kidney ischemia model, previously shown to reduce renal mass by ∼50% over 2-3 weeks. Stepwise azotemia/acute uremia was superimposed by inducing different lengths of contralateral (right) kidney ischemia (0, 15, 18, 20 min). Subsequent loss of left renal mass (kidney weight) was assessed 2 weeks later and contrasted with the degree of initial azotemia 24-h BUN. A striking correlation between 24-h BUNs and 2-week left renal mass was observed (r, 0.77; P < 0.001). With 20 min of right kidney ischemia, left kidney size was completely preserved. This preservation did not result from increased tubular cell proliferation or decreased microvascular loss, as gauged by KI-67 and CD-34 immunohistochemistry, respectively. Rather, an early reduction in proximal tubule cell dropout (as judged by renal cortical N-acetyl-glucosaminidase content), with a subsequent preservation of tubule mass, was observed. In summary, these findings advance a novel concept: acute uremia can confer early post-ischemic cytoprotection resulting in a slowed progression of post-ischemic kidney disease.

Effects of Instability Versus Traditional Resistance Training on Strength, Power and Velocity in Untrained Men

Directory of Open Access Journals (Sweden)

José Luis Maté-Muñoz

2014-09-01

Full Text Available The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10 or exercises executed in conditions of instability (using BOSU® and TRX® (IRT, n = 12. Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM, average (AV and peak velocity (PV, average (AP and peak power (PP, all during bench press (BP and back squat (BS exercises, along with squat jump (SJ height and counter movement jump (CMJ height. All variables were found to significantly improve (p <0.05 in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%, CMJ height (IRT = 17.7%, TRT = 15.2%, 1RM in BS (IRT = 13.03%, TRT = 12.6%, 1RM in BP (IRT = 4.7%, TRT = 4.4%, AP in BS (IRT = 10.5%, TRT = 9.3%, AP in BP (IRT = 2.4%, TRT = 8.1%, PP in BS (IRT=19.42%, TRT = 22.3%, PP in BP (IRT = 7.6%, TRT = 11.5%, AV in BS (IRT = 10.5%, TRT = 9.4%, and PV in BS (IRT = 8.6%, TRT = 4.5%. Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM, power, movement velocity and jumping ability.

Progression to Traditional Cigarette Smoking After Electronic Cigarette Use Among US Adolescents and Young Adults.

Science.gov (United States)

Primack, Brian A; Soneji, Samir; Stoolmiller, Michael; Fine, Michael J; Sargent, James D

2015-11-01

Electronic cigarettes (e-cigarettes) may help smokers reduce the use of traditional combustible cigarettes. However, adolescents and young adults who have never smoked traditional cigarettes are now using e-cigarettes, and these individuals may be at risk for subsequent progression to traditional cigarette smoking. To determine whether baseline use of e-cigarettes among nonsmoking and nonsusceptible adolescents and young adults is associated with subsequent progression along an established trajectory to traditional cigarette smoking. In this longitudinal cohort study, a national US sample of 694 participants aged 16 to 26 years who were never cigarette smokers and were attitudinally nonsusceptible to smoking cigarettes completed baseline surveys from October 1, 2012, to May 1, 2014, regarding smoking in 2012-2013. They were reassessed 1 year later. Analysis was conducted from July 1, 2014, to March 1, 2015. Multinomial logistic regression was used to assess the independent association between baseline e-cigarette use and cigarette smoking, controlling for sex, age, race/ethnicity, maternal educational level, sensation-seeking tendency, parental cigarette smoking, and cigarette smoking among friends. Sensitivity analyses were performed, with varying approaches to missing data and recanting. Use of e-cigarettes at baseline. Progression to cigarette smoking, defined using 3 specific states along a trajectory: nonsusceptible nonsmokers, susceptible nonsmokers, and smokers. Individuals who could not rule out smoking in the future were defined as susceptible. Among the 694 respondents, 374 (53.9%) were female and 531 (76.5%) were non-Hispanic white. At baseline, 16 participants (2.3%) used e-cigarettes. Over the 1-year follow-up, 11 of 16 e-cigarette users and 128 of 678 of those who had not used e-cigarettes (18.9%) progressed toward cigarette smoking. In the primary fully adjusted models, baseline e-cigarette use was independently associated with progression to smoking

Slow light in moving media

Science.gov (United States)

Leonhardt, U.; Piwnicki, P.

2001-06-01

We review the theory of light propagation in moving media with extremely low group velocity. We intend to clarify the most elementary features of monochromatic slow light in a moving medium and, whenever possible, to give an instructive simplified picture.

Oxytocin versus no treatment or delayed treatment for slow progress in the first stage of spontaneous labour.

Science.gov (United States)

Bugg, George J; Siddiqui, Farah; Thornton, Jim G

2013-06-23

Slow progress in the first stage of spontaneous labour is associated with an increased caesarean section rate and fetal and maternal morbidity. Oxytocin has long been advocated as a treatment for slow progress in labour but it is unclear to what extent it improves the outcomes for that labour and whether it actually reduces the caesarean section rate or maternal and fetal morbidity. This review will address the use of oxytocin and whether it improves the outcomes for women who are progressing slowly in labour compared to situations where it is not used or where its administration is delayed. To determine if the use of oxytocin for the treatment of slow progress in the first stage of spontaneous labour is associated with a reduction in the incidence of caesarean sections, or maternal and fetal morbidity compared to situations where it is not used or where its administration is delayed. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (23 February 2013) and bibliographies of relevant papers. Randomised controlled trials which compared oxytocin with either placebo, no treatment or delayed oxytocin in the active stage of spontaneous labour in low-risk women at term. Two authors independently assessed studies for inclusion, assessed risk of bias and extracted data. We sought additional information from trial authors. We included eight studies in the review involving a total of 1338 low-risk women in the first stage of spontaneous labour at term. Two comparisons were made; 1) the use of oxytocin versus placebo or no treatment (three trials); 2) the early use of oxytocin versus its delayed use (five trials). There were no significant differences in the rates of caesarean section or instrumental vaginal delivery in either comparison. Early use of oxytocin resulted in an increase in uterine hyperstimulation associated with fetal heart changes. However, the early use of oxytocin versus its delayed use resulted in no significant differences in a range

Effects of Instability Versus Traditional Resistance Training on Strength, Power and Velocity in Untrained Men

Science.gov (United States)

Maté-Muñoz, José Luis; Monroy, Antonio J. Antón; Jodra Jiménez, Pablo; Garnacho-Castaño, Manuel V.

2014-01-01

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key Points Similar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs. Both the stability and instability approaches

Mutually-modulated cross-gain modulation and slow light

International Nuclear Information System (INIS)

Sternklar, Shmuel; Sarid, Eyal; Wart, Maxim; Granot, Er'el

2010-01-01

The interaction of pump and Stokes light in a Brillouin medium, where both beams are modulated, can be utilized for controlling the group velocity of the amplified Stokes (or depleted pump). The dependence of the group velocity for this mutually-modulated cross-gain modulation (MMXGM) technique on the Brillouin gain parameter is studied. A sharp transition to slow light occurs in the G 1 α/β≈1 regime, where G 1 is the Brillouin gain parameter, and α and β are the pump and Stokes modulation indices, respectively. A comparison of MMXGM slow light to the Brillouin dispersion-based slow-light technique reveals the fundamental differences between them. The formation of higher harmonics of the modulation frequency is also discussed. The theoretical predictions are experimentally corroborated and potential applications in fiber-based sensing and interferometry are discussed

Embryonic Stem Cells-loaded Gelatin Microcryogels Slow Progression of Chronic Kidney Disease

Science.gov (United States)

Geng, Xiao-Dong; Zheng, Wei; Wu, Cong-Mei; Wang, Shu-Qiang; Hong, Quan; Cai, Guang-Yan; Chen, Xiang-Mei; Wu, Di

2016-01-01

Background: Chronic kidney disease (CKD) has become a public health problem. New interventions to slow or prevent disease progression are urgently needed. In this setting, cell therapies associated with regenerative effects are attracting increasing interest. We evaluated the effect of embryonic stem cells (ESCs) on the progression of CKD. Methods: Adult male Sprague–Dawley rats were subjected to 5/6 nephrectomy. We used pedicled greater omentum flaps packing ESC-loaded gelatin microcryogels (GMs) on the 5/6 nephrectomized kidney. The viability of ESCs within the GMs was detected using in vitro two-photon fluorescence confocal imaging. Rats were sacrificed after 12 weeks. Renal injury was evaluated using serum creatinine, urea nitrogen, 24 h protein, renal pathology, and tubular injury score results. Structural damage was evaluated by periodic acid-Schiff and Masson trichrome staining. Results: In vitro, ESCs could be automatically loaded into the GMs. Uniform cell distribution, good cell attachment, and viability were achieved from day 1 to 7 in vitro. After 12 weeks, in the pedicled greater omentum flaps packing ESC-loaded GMs on 5/6 nephrectomized rats group, the plasma urea nitrogen levels were 26% lower than in the right nephrectomy group, glomerulosclerosis index was 62% lower and tubular injury index was 40% lower than in the 5/6 nephrectomized rats group without GMs. Conclusions: In a rat model of established CKD, we demonstrated that the pedicled greater omentum flaps packing ESC-loaded GMs on the 5/6 nephrectomized kidney have a long-lasting therapeutic rescue function, as shown by the decreased progression of CKD and reduced glomerular injury. PMID:26879011

Slow Light by Two-Dimensional Photonic Crystal Waveguides

International Nuclear Information System (INIS)

Chao, Zhang; Yan, Huang; Xiao-Yu, Mao; Kai-Yu, Cui; Yi-Dong, Huang; Wei, Zhang; Jiang-De, Peng

2009-01-01

A simple and effective way to measure the group velocity of photonic crystal waveguides (PCWGs) is developed by using a fiber Mach–Zehnder interferometer. A PCWG with perfect air-bridge structure is fabricated and slow light with group velocity slower than c/80 is demonstrated. (fundamental areas of phenomenology (including applications))

Long-term control of HIV-1 in hemophiliacs carrying slow-progressing allele HLA-B*5101.

Science.gov (United States)

Kawashima, Yuka; Kuse, Nozomi; Gatanaga, Hiroyuki; Naruto, Takuya; Fujiwara, Mamoru; Dohki, Sachi; Akahoshi, Tomohiro; Maenaka, Katsumi; Goulder, Philip; Oka, Shinichi; Takiguchi, Masafumi

2010-07-01

HLA-B*51 alleles are reported to be associated with slow disease progression to AIDS, but the mechanism underlying this association is still unclear. In the present study, we analyzed the effect of HLA-B*5101 on clinical outcome for Japanese hemophiliacs who had been infected with HIV-1 before 1985 and had been recruited in 1998 for this study. HLA-B*5101(+) hemophiliacs exhibited significantly slow progression. The analysis of HLA-B*5101-restricted HIV-1-specific cytotoxic T-lymphocyte (CTL) responses to 4 HLA-B*-restricted epitopes in 10 antiretroviral-therapy (ART)-free HLA-B*5101(+) hemophiliacs showed that the frequency of Pol283-8-specific CD8(+) T cells was inversely correlated with the viral load, whereas the frequencies of CD8(+) T cells specific for 3 other epitopes were positively correlated with the viral load. The HLA-B*5101(+) hemophiliacs whose HIV-1 replication had been controlled for approximately 25 years had HIV-1 possessing the wild-type Pol283-8 sequence or the Pol283-8V mutant, which does not critically affect T-cell recognition, whereas other HLA-B*5101(+) hemophiliacs had HIV-1 with escape mutations in this epitope. The results suggest that the control of HIV-1 over approximately 25 years in HLA-B*5101-positive hemophiliacs is associated with a Pol283-8-specific CD8(+) T-cell response and that lack of control of HIV-1 is associated with the appearance of Pol283-8-specific escape mutants.

Progress towards experimental realization of extreme-velocity flow-dominated magnetized plasmas

Science.gov (United States)

Weber, T. E.; Adams, C. S.; Welch, D. R.; Kagan, G.; Bean, I. A.; Henderson, B. R.; Klim, A. J.

2017-10-01

Interactions of flow-dominated plasmas with other plasmas, neutral gases, magnetic fields, solids etc., take place with sufficient velocity that kinetic energy dominates the dynamics of the interaction (as opposed to magnetic or thermal energy, which dominates in most laboratory plasma experiments). Building upon progress made by the Magnetized Shock Experiment (MSX) at LANL, we are developing the experimental and modeling capability to increase our ultimate attainable plasma velocities well in excess of 1000 km/s. Ongoing work includes designing new pulsed power switches, triggering, and inductive adder topologies; development of novel high-speed optical diagnostics; and exploration of new numerical techniques to specifically model the unique physics of translating/stagnating flow-dominated plasmas. Furthering our understanding of the physical mechanisms of energy conversion from kinetic to other forms, such as thermal energy, non-thermal tails/accelerated populations, enhanced magnetic fields, and radiation (both continuum and line), has wide-ranging significance in basic plasma science, astrophysics, and plasma technology applications such as inertial confinement fusion and intense radiation sources. This work is supported by the U.S. Department of Energy, National Nuclear Security Administration. LA-UR-17-25786.

Endothelin-A receptor blockade slows the progression of renal injury in experimental renovascular disease.

Science.gov (United States)

Kelsen, Silvia; Hall, John E; Chade, Alejandro R

2011-07-01

Endothelin (ET)-1, a potent renal vasoconstrictor with mitogenic properties, is upregulated by ischemia and has been shown to induce renal injury via the ET-A receptor. The potential role of ET-A blockade in chronic renovascular disease (RVD) has not, to our knowledge, been previously reported. We hypothesized that chronic ET-A receptor blockade would preserve renal hemodynamics and slow the progression of injury of the stenotic kidney in experimental RVD. Renal artery stenosis, a major cause of chronic RVD, was induced in 14 pigs and observed for 6 wk. In half of the pigs, chronic ET-A blockade was initiated (RVD+ET-A, 0.75 mg·kg(-1)·day(-1)) at the onset of RVD. Single-kidney renal blood flow, glomerular filtration rate, and perfusion were quantified in vivo after 6 wk using multidetector computer tomography. Renal microvascular density was quantified ex vivo using three-dimensional microcomputer tomography, and growth factors, inflammation, apoptosis, and fibrosis were determined in renal tissue. The degree of stenosis and increase in blood pressure were similar in RVD and RVD+ET-A pigs. Renal hemodynamics, function, and microvascular density were decreased in the stenotic kidney but preserved by ET-A blockade, accompanied by increased renal expression of vascular endothelial growth factor, hepatocyte growth factor, and downstream mediators such as phosphorilated-Akt, angiopoietins, and endothelial nitric oxide synthase. ET-A blockade also reduced renal apoptosis, inflammation, and glomerulosclerosis. This study shows that ET-A blockade slows the progression of renal injury in experimental RVD and preserves renal hemodynamics, function, and microvascular density in the stenotic kidney. These results support a role for ET-1/ET-A as a potential therapeutic target in chronic RVD.

Reflective Practice in the Ballet Class: Bringing Progressive Pedagogy to the Classical Tradition

Science.gov (United States)

Zeller, Jessica

2017-01-01

This research seeks to broaden the dialogue on progressive ballet pedagogy through an examination of reflective practices in the ballet class. Ballet's traditional model of instruction has long required students to quietly comply with the pedagogue's directives, and it has thus become notorious for promoting student passivity. Despite strong…

Observaton of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides

DEFF Research Database (Denmark)

Ha, Sangwoo; Sukhorukov, Andrey A.; Lavrinenko, Andrei

2011-01-01

We report the experimental observation of tunneling of slow and fast electromagnetic modes in coupled periodic waveguides shifted longitudinally by half of modulation period. According to the symmetry analysis, such a coupler supports two electromagnetic modes with exactly matched slow or fast...... group velocities but different phase velocities for frequencies close to the edge of the photonic band. We confirm the predicted properties of the modes by directly extracting their dispersion and group velocities from the near-field measurements using specialized Bloch-wave spectral analysis method....

High Velocity Gas Gun

Science.gov (United States)

1988-01-01

A video tape related to orbital debris research is presented. The video tape covers the process of loading a High Velocity Gas Gun and firing it into a mounted metal plate. The process is then repeated in slow motion.

Connecting slow earthquakes to huge earthquakes.

Science.gov (United States)

Obara, Kazushige; Kato, Aitaro

2016-07-15

Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes. Copyright © 2016, American Association for the Advancement of Science.

New diagnostic technique for Zeeman-compensated atomic beam slowing: technique and results

OpenAIRE

Molenaar, P.A.; Straten, P. van der; Heideman, H.G.M.; Metcalf, H.

1997-01-01

We have developed a new diagnostic tool for the study of Zeeman-compensated slowing of an alkali atomic beam. Our time-of-flight technique measures the longitudinal veloc- ity distribution of the slowed atoms with a resolution below the Doppler limit of 30 cm/s. Furthermore, it can map the position and velocity distribution of atoms in either ground hyperfine level inside the solenoid without any devices inside the solenoid. The technique reveals the optical pumping ef- fects, and shows in de...

Zero-velocity solitons in high-index photonic crystal fibers

DEFF Research Database (Denmark)

Lægsgaard, Jesper

2011-01-01

Nonlinear propagation in slow-light states of high-index photonic crystal fibers (PCFs) is studied numerically. To avoid divergencies in dispersion and nonlinear parameters around the zero-velocity mode, a time-propagating generalized nonlinear Schrödinger equation is formulated. Calculated slow-...

Optically stimulated slowing of polar heavy-atom molecules with a constant beat phase

Science.gov (United States)

Yin, Yanning; Xu, Supeng; Xia, Meng; Xia, Yong; Yin, Jianping

2018-04-01

Polar heavy-atom molecules have been well recognized as promising candidates for precision measurements and tests of fundamental physics. A much slower molecular beam to increase the interaction time should lead to a more sensitive measurement. Here we theoretically demonstrate the possibility of the stimulated longitudinal slowing of heavy-atom molecules by the coherent optical bichromatic force with a constant beat phase. Taking the YbF meolecule as an example, we show that a rapid and short-distance deceleration of heavy molecules by a phase-compensation method is feasible with moderate conditions. A molecular beam of YbF with a forward velocity of 120 m/s can be decelerated below 10 m/s within a distance of 3.5 cm and with a laser irradiance for each traveling wave of 107.2 W/cm 2 . Our proposed slowing method could be a promising approach to break through the space constraint or the limited capture efficiency of molecules loadable into a magneto-optical trap in traditional deceleration schemes, opening the possibility for a significant improvement of the precision measurement sensitivity.

Structural slow light can enhance Beer-Lambert absorption

OpenAIRE

Dicaire Isabelle; Chin Sanghoon; Thévenaz Luc

2011-01-01

We experimentally demonstrate that structural slow light can enhance Beer-Lambert absorption. A 4-fold reduction of the group velocity induced by mere cavity effects has caused an increase of molecular absorption by 130%.

Conduction velocity is regulated by sodium channel inactivation in unmyelinated axons innervating the rat cranial meninges.

Science.gov (United States)

De Col, Roberto; Messlinger, Karl; Carr, Richard W

2008-02-15

Axonal conduction velocity varies according to the level of preceding impulse activity. In unmyelinated axons this typically results in a slowing of conduction velocity and a parallel increase in threshold. It is currently held that Na(+)-K(+)-ATPase-dependent axonal hyperpolarization is responsible for this slowing but this has long been equivocal. We therefore examined conduction velocity changes during repetitive activation of single unmyelinated axons innervating the rat cranial meninges. In direct contradiction to the currently accepted postulate, Na(+)-K(+)-ATPase blockade actually enhanced activity-induced conduction velocity slowing, while the degree of velocity slowing was curtailed in the presence of lidocaine (10-300 microm) and carbamazepine (30-500 microm) but not tetrodotoxin (TTX, 10-80 nm). This suggests that a change in the number of available sodium channels is the most prominent factor responsible for activity-induced changes in conduction velocity in unmyelinated axons. At moderate stimulus frequencies, axonal conduction velocity is determined by an interaction between residual sodium channel inactivation following each impulse and the retrieval of channels from inactivation by a concomitant Na(+)-K(+)-ATPase-mediated hyperpolarization. Since the process is primarily dependent upon sodium channel availability, tracking conduction velocity provides a means of accessing relative changes in the excitability of nociceptive neurons.

MicroRNA-124 slows down the progression of Huntington′s disease by promoting neurogenesis in the striatum

Directory of Open Access Journals (Sweden)

Tian Liu

2015-01-01

Full Text Available MicroRNA-124 contributes to neurogenesis through regulating its targets, but its expression both in the brain of Huntington′s disease mouse models and patients is decreased. However, the effects of microRNA-124 on the progression of Huntington′s disease have not been reported. Results from this study showed that microRNA-124 increased the latency to fall for each R6/2 Huntington′s disease transgenic mouse in the rotarod test. 5-Bromo-2′-deoxyuridine (BrdU staining of the striatum shows an increase in neurogenesis. In addition, brain-derived neurotrophic factor and peroxisome proliferator-activated receptor gamma coactivator 1-alpha protein levels in the striatum were increased and SRY-related HMG box transcription factor 9 protein level was decreased. These findings suggest that microRNA-124 slows down the progression of Huntington′s disease possibly through its important role in neuronal differentiation and survival.

Photonic crystal waveguides with semi-slow light and tailored dispersion properties

DEFF Research Database (Denmark)

Frandsen, Lars Hagedorn; Lavrinenko, Andrei; Fage-Pedersen, Jacob

2006-01-01

waveguide with either vanishing, positive, or negative group velocity dispersion and semi-slow light. We realize experimentally a silicon-on-insulator photonic crystal waveguide having nearly constant group velocity [similar to]c$-0$//34 in an 11-nm bandwidth below the silica-line. $CPY@2006 Optical Society...

Long-Term Control of HIV-1 in Hemophiliacs Carrying Slow-Progressing Allele HLA-B*5101▿ †

Science.gov (United States)

Kawashima, Yuka; Kuse, Nozomi; Gatanaga, Hiroyuki; Naruto, Takuya; Fujiwara, Mamoru; Dohki, Sachi; Akahoshi, Tomohiro; Maenaka, Katsumi; Goulder, Philip; Oka, Shinichi; Takiguchi, Masafumi

2010-01-01

HLA-B*51 alleles are reported to be associated with slow disease progression to AIDS, but the mechanism underlying this association is still unclear. In the present study, we analyzed the effect of HLA-B*5101 on clinical outcome for Japanese hemophiliacs who had been infected with HIV-1 before 1985 and had been recruited in 1998 for this study. HLA-B*5101+ hemophiliacs exhibited significantly slow progression. The analysis of HLA-B*5101-restricted HIV-1-specific cytotoxic T-lymphocyte (CTL) responses to 4 HLA-B*-restricted epitopes in 10 antiretroviral-therapy (ART)-free HLA-B*5101+ hemophiliacs showed that the frequency of Pol283-8-specific CD8+ T cells was inversely correlated with the viral load, whereas the frequencies of CD8+ T cells specific for 3 other epitopes were positively correlated with the viral load. The HLA-B*5101+ hemophiliacs whose HIV-1 replication had been controlled for approximately 25 years had HIV-1 possessing the wild-type Pol283-8 sequence or the Pol283-8V mutant, which does not critically affect T-cell recognition, whereas other HLA-B*5101+ hemophiliacs had HIV-1 with escape mutations in this epitope. The results suggest that the control of HIV-1 over approximately 25 years in HLA-B*5101-positive hemophiliacs is associated with a Pol283-8-specific CD8+ T-cell response and that lack of control of HIV-1 is associated with the appearance of Pol283-8-specific escape mutants. PMID:20410273

Slowing down bubbles with sound

Science.gov (United States)

Poulain, Cedric; Dangla, Remie; Guinard, Marion

2009-11-01

We present experimental evidence that a bubble moving in a fluid in which a well-chosen acoustic noise is superimposed can be significantly slowed down even for moderate acoustic pressure. Through mean velocity measurements, we show that a condition for this effect to occur is for the acoustic noise spectrum to match or overlap the bubble's fundamental resonant mode. We render the bubble's oscillations and translational movements using high speed video. We show that radial oscillations (Rayleigh-Plesset type) have no effect on the mean velocity, while above a critical pressure, a parametric type instability (Faraday waves) is triggered and gives rise to nonlinear surface oscillations. We evidence that these surface waves are subharmonic and responsible for the bubble's drag increase. When the acoustic intensity is increased, Faraday modes interact and the strongly nonlinear oscillations behave randomly, leading to a random behavior of the bubble's trajectory and consequently to a higher slow down. Our observations may suggest new strategies for bubbly flow control, or two-phase microfluidic devices. It might also be applicable to other elastic objects, such as globules, cells or vesicles, for medical applications such as elasticity-based sorting.

Effects of body mass index on gastric slow wave: a magnetogastrographic study

International Nuclear Information System (INIS)

Somarajan, S; Cassilly, S; Obioha, C; Bradshaw, L A; Richards, W O

2014-01-01

We measured gastric slow wave activity simultaneously with magnetogastrogram (MGG), mucosal electromyogram (EMG) and electrogastrogram (EGG) in human subjects with varying body mass index (BMI) before and after a meal. In order to investigate the effect of BMI on gastric slow wave parameters, each subject's BMI was calculated and divided into two groups: subjects with BMI ≤ 27 and BMI > 27. Signals were processed with Fourier spectral analysis and second-order blind identification (SOBI) techniques. Our results showed that increased BMI does not affect signal characteristics such as frequency and amplitude of EMG and MGG. Comparison of the postprandial EGG power, on the other hand, showed a statistically significant reduction in subjects with BMI > 27 compared with BMI ≤ 27. In addition to the frequency and amplitude, the use of SOBI-computed propagation maps from MGG data allowed us to visualize the propagating slow wave and compute the propagation velocity in both BMI groups. No significant change in velocity with increasing BMI or meal was observed in our study. In conclusion, multichannel MGG provides an assessment of frequency, amplitude and propagation velocity of the slow wave in subjects with differing BMI categories and was observed to be independent of BMI. (paper)

Generation of a slow and continuous cesium atomic beam for an atomic clock

International Nuclear Information System (INIS)

Park, Sang Eon; Lee, Ho Seong; Shin, Eun-joo; Kwon, Taeg Yong; Yang, Sung Hoon; Cho, Hyuck

2002-01-01

A thermal atomic beam from a cesium oven was slowed down by use of the Hoffnagle modified white-light cooling technique. In addition, the atomic beam was collimated by use of a two-dimensional optical molasses that was installed transverse to the atomic-beam direction. The flux of the atomic beam was 2x10 10 atoms/s, an increase of a factor of 16 as a result of the collimation. The mean longitudinal velocity was ∼24.4 m/s, and the rms velocity spread of the slowed atomic beam was ∼1 m/s. Compared with other methods, we found that the Hoffnagle method is suitable for the generation of slow atomic beams to be used in an atomic clock, which requires an ultralow magnetic field environment. This atomic beam was deflected by an angle of 30 deg. by a one-dimensional optical molasses to separate it from laser light and high-velocity atoms

New diagnostic technique for Zeeman-compensated atomic beam slowing: technique and results

NARCIS (Netherlands)

Molenaar, P.A.; Straten, P. van der; Heideman, H.G.M.; Metcalf, H.

1997-01-01

We have developed a new diagnostic tool for the study of Zeeman-compensated slowing of an alkali atomic beam. Our time-of-flight technique measures the longitudinal veloc- ity distribution of the slowed atoms with a resolution below the Doppler limit of 30 cm/s. Furthermore, it can map

Estimated carotid-femoral pulse wave velocity has similar predictive value as measured carotid-femoral pulse wave velocity

DEFF Research Database (Denmark)

Greve, Sara V; Blicher, Marie K; Kruger, Ruan

2016-01-01

BACKGROUND: Carotid-femoral pulse wave velocity (cfPWV) adds significantly to traditional cardiovascular risk prediction, but is not widely available. Therefore, it would be helpful if cfPWV could be replaced by an estimated carotid-femoral pulse wave velocity (ePWV) using age and mean blood pres...... that these traditional risk scores have underestimated the complicated impact of age and blood pressure on arterial stiffness and cardiovascular risk....

Mid-term results of bariatric surgery in morbidly obese Japanese patients with slow progressive autoimmune diabetes.

Science.gov (United States)

Uno, Kohei; Seki, Yosuke; Kasama, Kazunori; Wakamatsu, Kotaro; Hashimoto, Kenkichi; Umezawa, Akiko; Yanaga, Katsuhiko; Kurokawa, Yoshimochi

2017-12-11

Bariatric surgery is recognized as an effective treatment for type 2 diabetes mellitus, but data on its efficacy for type 1 diabetes mellitus, especially slowly progressive insulin-dependent diabetes mellitus, are limited. We investigated five Japanese patients with slowly progressive insulin-dependent diabetes mellitus who underwent bariatric surgery at our center. Five morbidly obese glutamic acid decarboxylase antibody-positive diabetic patients underwent two different types of bariatric surgery. The mean titer of anti-glutamic acid decarboxylase antibody was 4.6 U/mL, and the mean preoperative bodyweight and BMI were 113 kg and 39.6 kg/m 2 , respectively. The mean hemoglobin A1c was 8.4%. The mean fasting serum C-peptide was 5.0 ng/mL. Laparoscopic sleeve gastrectomy was performed in two patients, while laparoscopic sleeve gastrectomy with duodenojejunal bypass was performed in three patients. At one year after surgery, the mean bodyweight and BMI significantly dropped, and the mean percentage of excess weight loss was 96.4%. The mean hemoglobin A1c was 5.7%. This favorable trend was maintained at mid-term. Bariatric surgery for morbidly obese patients with anti-glutamic acid decarboxylase antibody-positive type 1 diabetes mellitus, especially slow progressive autoimmune diabetes, seemed effective in achieving mid-term glycemic control. Longer follow-up with a larger number of patients, as well as validation with more advanced patients with slowly progressive insulin-dependent diabetes mellitus, will be needed. © 2017 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

Limits of slow light in photonic crystals

DEFF Research Database (Denmark)

Pedersen, Jesper Goor; Xiao, Sanshui; Mortensen, N. Asger

2008-01-01

in the group velocity acquiring a finite value above zero at the band-gap edges while attaining uperluminal values within the band gap. Simple scalings of the minimum and maximum group velocities with the imaginary part of the dielectric function or, equivalently, the linewidth of the broadened states......While ideal photonic crystals would support modes with a vanishing group velocity, state-of-the-art structures have still only provided a slow down by roughly two orders of magnitude. We find that the induced density of states caused by lifetime broadening of the electromagnetic modes results...... are presented. The results obtained are entirely general and may be applied to any effect which results in a broadening of the electromagnetic states, such as loss, disorder, and finite-size effects. This significantly limits the reduction in group velocity attainable via photonic crystals....

Crystal plastic earthquakes in dolostones: from slow to fast ruptures.

Science.gov (United States)

Passelegue, F. X.; Aubry, J.; Nicolas, A.; Fondriest, M.; Schubnel, A.; Di Toro, G.

2017-12-01

Dolostone is the most dominant lithology of the seismogenic upper crust around the Mediterranean Sea. Understanding the internal mechanisms controlling fault friction is crucial for understanding seismicity along active faults. Displacement in such fault zones is frequently highlighted by highly reflective (mirror-like) slip surfaces, created by thin films of nanogranular fault rock. Using saw-cut dolostone samples coming from natural fault zones, we conducted stick-slip experiments under triaxial loading conditions at 30, 60 and 90 MPa confining pressure and temperature ranging from 30 to 100 degrees C. At 30 and 65 degrees C, only slow rupture was observed and the experimental fault exhibits frictional behaviour, i.e. a dependence of normal stress on peak shear stress. At 65 degrees C, a strengthening behaviour is observed after the main rupture, leading to a succession of slow rupture. At 100 degrees C, the macroscopic behaviour of the fault becomes ductile, and no dependence of pressure on the peak shear stress is observed. In addition, the increase of the confining pressure up to 60 and 90 MPa allow the transition from slow to fast rupture, highlighted by the records of acoustic activity and by dynamic stress drop occurring in a few tens of microseconds. Using strain gages located along the fault surface and acoustic transducers, we were able to measure the rupture velocities during slow and fast rupture. Slow ruptures propagated around 0.1 m/s, in agreement with natural observations. Fast ruptures propagated up to supershear velocities, i.e. faster than the shear wave speed (>3500 m/s). A complete study of the microstructures was realized before and after ruptures. Slow ruptures lead to the production of mirror-like surface driven by the production of nanograins due to dislocation processes. Fast ruptures induce the production of amorphous material along the fault surface, which may come from decarbonation and melting processes. We demonstrate that the

Correlation between radiographic, echographic and MRI changes and rheumatoid arthritis progression

Directory of Open Access Journals (Sweden)

G. Garlaschi

2011-09-01

Full Text Available Objectives: To review the imaging methods used for the evaluation of disease progression in rheumatoid arthritis (RA and to evaluate the results of their application in pharmacological trials. Methods: Literature articles dealing with radiology, echography, and magnetic resonance imaging (MRI of patients with RA were evaluated in a non-systematic fashion. Results: Conventional radiology is the gold standard for the evaluation of disease progression in RA because of its diffusion, economy, and standardization. Different techniques have been proposed to evaluate radiological damage of the joints, with the Larsen’s and Sharp’s methods being most widely used. These methods are commonly used for the evaluation of the ability of DMARDs to slow RA progression. Among traditional DMARDs, gold salts, sulphasalazine, methotrexate, cyclosporin, and leflunomide have shown efficacy in slowing the appearance of new erosions. The same effect has been recently demonstrated for infliximab plus methotrexate, anakinra and etanercept. However, conventional radiology has several disadvantages, because it is monoplanar and has a low sensitivity to change. Newer imaging techniques, such as echography and MRI are extensively studied and have been used occasionally in the mediumterm evaluation of DMARDs, with promising results. Conclusions: Although conventional radiology is still the gold standard for the evaluation of disease progression in RA, newer techniques are increasingly studied. In particular, standardization of echographic and MRI imaging of the joints is in progress.

Sound Velocity in Soap Foams

International Nuclear Information System (INIS)

Wu Gong-Tao; Lü Yong-Jun; Liu Peng-Fei; Li Yi-Ning; Shi Qing-Fan

2012-01-01

The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method. It is found that the sound velocities increase with increasing bubble diameter, and asymptotically approach to the value in air when the diameter is larger than 12.5 mm. We propose a simple theoretical model for the sound propagation in a disordered foam. In this model, the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length. This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments. Further measurements indicate that the increase of frequency markedly slows down the sound velocity, whereas the latter does not display a strong dependence on the solution concentration

Loss of Ikbkap Causes Slow, Progressive Retinal Degeneration in a Mouse Model of Familial Dysautonomia.

Science.gov (United States)

Ueki, Yumi; Ramirez, Grisela; Salcedo, Ernesto; Stabio, Maureen E; Lefcort, Frances

2016-01-01

Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that is caused by a mutation in the gene for inhibitor of kappa B kinase complex-associated protein ( IKBKAP ). Although FD patients suffer from multiple neuropathies, a major debilitation that affects their quality of life is progressive blindness. To determine the requirement for Ikbkap in the developing and adult retina, we generated Ikbkap conditional knockout (CKO) mice using a TUBA1a promoter-Cre ( Tα1-Cre ). In the retina, Tα1-Cre expression is detected predominantly in retinal ganglion cells (RGCs). At 6 months, significant loss of RGCs had occurred in the CKO retinas, with the greatest loss in the temporal retina, which is the same spatial phenotype observed in FD, Leber hereditary optic neuropathy, and dominant optic atrophy. Interestingly, the melanopsin-positive RGCs were resistant to degeneration. By 9 months, signs of photoreceptor degeneration were observed, which later progressed to panretinal degeneration, including RGC and photoreceptor loss, optic nerve thinning, Müller glial activation, and disruption of layers. Taking these results together, we conclude that although Ikbkap is not required for normal development of RGCs, its loss causes a slow, progressive RGC degeneration most severely in the temporal retina, which is later followed by indirect photoreceptor loss and complete retinal disorganization. This mouse model of FD is not only useful for identifying the mechanisms mediating retinal degeneration, but also provides a model system in which to attempt to test therapeutics that may mitigate the loss of vision in FD patients.

Slow waves in microchannel metal waveguides and application to particle acceleration

Directory of Open Access Journals (Sweden)

L. C. Steinhauer

2003-06-01

Full Text Available Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO_{2} lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ∼0.6  mm. The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

Slow waves in microchannel metal waveguides and application to particle acceleration

Science.gov (United States)

Steinhauer, L. C.; Kimura, W. D.

2003-06-01

Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong exchange of energy can occur between a beam of charged particles and this slow-waveguide mode. Moreover, the energy exchange can be sustained over a distance limited only by the natural damping of the wave. This makes the microchannel metal waveguide an attractive possibility for high-gradient electron laser acceleration because the wave can be directly energized by a long-wavelength laser. Indeed the frequency of CO2 lasers lies at a fortuitous wavelength that produces a strong laser-particle interaction in a channel of reasonable macroscopic size (e.g., ˜0.6 mm). The dispersion properties including phase velocity and damping for the slow wave are developed. The performance and other issues related to laser accelerator applications are discussed.

Slow and fast light in semiconductor waveguides

DEFF Research Database (Denmark)

Mørk, Jesper; Hansen, Per Lunnemann; Xue, Weiqi

2010-01-01

Investigations of slow and fast light effects in semiconductor waveguides entail interesting physics and point to a number of promising applications. In this review we give an overview of recent progress in the field, in particular focusing on the physical mechanisms of electromagnetically induced...... transparency and coherent population oscillations. While electromagnetically induced transparency has been the most important effect in realizing slowdown effects in atomic gasses, progress has been comparatively slow in semiconductors due to inherent problems of fast dephasing times and inhomogeneous...... broadening in quantum dots. The physics of electromagnetically induced transparency in semiconductors is discussed, emphasizing these limitations and recent suggestions for overcoming them. On the other hand, the mechanism of coherent population oscillations relies on wave mixing effects and is well suited...

Curcumin slows osteoarthritis progression and relieves osteoarthritis-associated pain symptoms in a post-traumatic osteoarthritis mouse model.

Science.gov (United States)

Zhang, Zhuo; Leong, Daniel J; Xu, Lin; He, Zhiyong; Wang, Angela; Navati, Mahantesh; Kim, Sun J; Hirsh, David M; Hardin, John A; Cobelli, Neil J; Friedman, Joel M; Sun, Hui B

2016-06-03

Curcumin has been shown to have chondroprotective potential in vitro. However, its effect on disease and symptom modification in osteoarthritis (OA) is largely unknown. This study aimed to determine whether curcumin could slow progression of OA and relieve OA-related pain in a mouse model of destabilization of the medial meniscus (DMM). Expression of selected cartilage degradative-associated genes was evaluated in human primary chondrocytes treated with curcumin and curcumin nanoparticles and assayed by real-time PCR. The mice subjected to DMM surgery were orally administered curcumin or topically administered curcumin nanoparticles for 8 weeks. Cartilage integrity was evaluated by Safranin O staining and Osteoarthritis Research Society International (OARSI) score, and by immunohistochemical staining of cleaved aggrecan and type II collagen, and levels of matrix metalloproteinase (MMP)-13 and ADAMTS5. Synovitis and subchondral bone thickness were scored based on histologic images. OA-associated pain and symptoms were evaluated by von Frey assay, and locomotor behavior including distance traveled and rearing. Both curcumin and nanoparticles encapsulating curcumin suppressed mRNA expression of pro-inflammatory mediators IL-1β and TNF-α, MMPs 1, 3, and 13, and aggrecanase ADAMTS5, and upregulated the chondroprotective transcriptional regulator CITED2, in primary cultured chondrocytes in the absence or presence of IL-1β. Oral administration of curcumin significantly reduced OA disease progression, but showed no significant effect on OA pain relief. Curcumin was detected in the infrapatellar fat pad (IPFP) following topical administration of curcumin nanoparticles on the skin of the injured mouse knee. Compared to vehicle-treated controls, topical treatment led to: (1) reduced proteoglycan loss and cartilage erosion and lower OARSI scores, (2) reduced synovitis and subchondral plate thickness, (3) reduced immunochemical staining of type II collagen and aggrecan

Mechanism of abnormally slow crystal growth of CuZr alloy

International Nuclear Information System (INIS)

Yan, X. Q.; Lü, Y. J.

2015-01-01

Crystal growth of the glass-forming CuZr alloy is shown to be abnormally slow, which suggests a new method to identify the good glass-forming alloys. The crystal growth of elemental Cu, Pd and binary NiAl, CuZr alloys is systematically studied with the aid of molecular dynamics simulations. The temperature dependence of the growth velocity indicates the different growth mechanisms between the elemental and the alloy systems. The high-speed growth featuring the elemental metals is dominated by the non-activated collision between liquid-like atoms and interface, and the low-speed growth for NiAl and CuZr is determined by the diffusion across the interface. We find that, in contrast to Cu, Pd, and NiAl, a strong stress layering arisen from the density and the local order layering forms in front of the liquid-crystal interface of CuZr alloy, which causes a slow diffusion zone. The formation of the slow diffusion zone suppresses the interface moving, resulting in much small growth velocity of CuZr alloy. We provide a direct evidence of this explanation by applying the compressive stress normal to the interface. The compression is shown to boost the stress layering in CuZr significantly, correspondingly enhancing the slow diffusion zone, and eventually slowing down the crystal growth of CuZr alloy immediately. In contrast, the growth of Cu, Pd, and NiAl is increased by the compression because the low diffusion zones in them are never well developed

Increase in Leg Stiffness Reduces Joint Work During Backpack Carriage Running at Slow Velocities.

Science.gov (United States)

Liew, Bernard; Netto, Kevin; Morris, Susan

2017-10-01

Optimal tuning of leg stiffness has been associated with better running economy. Running with a load is energetically expensive, which could have a significant impact on athletic performance where backpack carriage is involved. The purpose of this study was to investigate the impact of load magnitude and velocity on leg stiffness. We also explored the relationship between leg stiffness and running joint work. Thirty-one healthy participants ran overground at 3 velocities (3.0, 4.0, 5.0 m·s -1 ), whilst carrying 3 load magnitudes (0%, 10%, 20% weight). Leg stiffness was derived using the direct kinetic-kinematic method. Joint work data was previously reported in a separate study. Linear models were used to establish relationships between leg stiffness and load magnitude, velocity, and joint work. Our results found that leg stiffness did not increase with load magnitude. Increased leg stiffness was associated with reduced total joint work at 3.0 m·s -1 , but not at faster velocities. The association between leg stiffness and joint work at slower velocities could be due to an optimal covariation between skeletal and muscular components of leg stiffness, and limb attack angle. When running at a relatively comfortable velocity, greater leg stiffness may reflect a more energy efficient running pattern.

Velocity distribution of electrons in time-varying low-temperature plasmas: progress in theoretical procedures over the past 70 years

Science.gov (United States)

Makabe, Toshiaki

2018-03-01

A time-varying low-temperature plasma sustained by electrical powers with various kinds of fRequencies has played a key role in the historical development of new technologies, such as gas lasers, ozonizers, micro display panels, dry processing of materials, medical care, and so on, since World War II. Electrons in a time-modulated low-temperature plasma have a proper velocity spectrum, i.e. velocity distribution dependent on the microscopic quantum characteristics of the feed gas molecule and on the external field strength and the frequency. In order to solve and evaluate the time-varying velocity distribution, we have mostly two types of theoretical methods based on the classical and linear Boltzmann equations, namely, the expansion method using the orthogonal function and the procedure of non-expansional temporal evolution. Both methods have been developed discontinuously and progressively in synchronization with those technological developments. In this review, we will explore the historical development of the theoretical procedure to evaluate the electron velocity distribution in a time-varying low-temperature plasma over the past 70 years.

Agradient velocity, vortical motion and gravity waves in a rotating shallow-water model

Science.gov (United States)

Sutyrin Georgi, G.

2004-07-01

A new approach to modelling slow vortical motion and fast inertia-gravity waves is suggested within the rotating shallow-water primitive equations with arbitrary topography. The velocity is exactly expressed as a sum of the gradient wind, described by the Bernoulli function,B, and the remaining agradient part, proportional to the velocity tendency. Then the equation for inverse potential vorticity,Q, as well as momentum equations for agradient velocity include the same source of intrinsic flow evolution expressed as a single term J (B, Q), where J is the Jacobian operator (for any steady state J (B, Q) = 0). Two components of agradient velocity are responsible for the fast inertia-gravity wave propagation similar to the traditionally used divergence and ageostrophic vorticity. This approach allows for the construction of balance relations for vortical dynamics and potential vorticity inversion schemes even for moderate Rossby and Froude numbers assuming the characteristic value of |J(B, Q)| = to be small. The components of agradient velocity are used as the fast variables slaved to potential vorticity that allows for diagnostic estimates of the velocity tendency, the direct potential vorticity inversion with the accuracy of 2 and the corresponding potential vorticity-conserving agradient velocity balance model (AVBM). The ultimate limitations of constructing the balance are revealed in the form of the ellipticity condition for balanced tendency of the Bernoulli function which incorporates both known criteria of the formal stability: the gradient wind modified by the characteristic vortical Rossby wave phase speed should be subcritical. The accuracy of the AVBM is illustrated by considering the linear normal modes and coastal Kelvin waves in the f-plane channel with topography.

Tailoring group velocity by topology optimization

DEFF Research Database (Denmark)

Stainko, Roman; Sigmund, Ole

2007-01-01

The paper describes a systematic method for the tailoring of dispersion properties of slab-based photonic crystal waveguides. The method is based on the topology optimization method which consists in repeated finite element frequency domain analyses. The goal of the optimization process is to come...... up with slow light, zero group velocity dispersion photonic waveguides or photonic waveguides with tailored dispersion properties for dispersion compensation purposes. An example concerning the design of a wide bandwidth, constant low group velocity waveguide demonstrate the e±ciency of the method....

Systematic dependence on the slowing down environment, of nuclear lifetime measurements by DSAM

International Nuclear Information System (INIS)

Toulemonde, M.; Haas, F.

1976-01-01

The meanlife of the 22 Ne 3.34MeV level measured by DSAM (Doppler Shift Attenuation Method) at an average velocity of 0.009 c, shows large fluctuations with different slowing down materials ranging from Li to Pb. These fluctuations are correlated with a linear dependence of the 'apparent' meanlife tau on the electronic slowing down time

A Primer to Slow Light

OpenAIRE

Leonhardt, U.

2001-01-01

Laboratory-based optical analogs of astronomical objects such as black holes rely on the creation of light with an extremely low or even vanishing group velocity (slow light). These brief notes represent a pedagogical attempt towards elucidating this extraordinary form of light. This paper is a contribution to the book Artificial Black Holes edited by Mario Novello, Matt Visser and Grigori Volovik. The paper is intended as a primer, an introduction to the subject for non-experts, not as a det...

Influence of many-particle interactions on slow light phenomena in quantum dots

DEFF Research Database (Denmark)

Houmark-Nielsen, Jakob; Jauho, Antti-Pekka; Nielsen, Torben Roland

2008-01-01

We investigate the impact of many-particle interactions on group-velocity slowdown achieved via Electromagnetically Induced Transparency (EIT) in quantum dots. Using a ladder scheme we find in the steady-state an increase in maximum slow-down as compared to the non-interacting case, which can...... be attributed to Coulomb interaction effects. The necessary pump power at which maximum slow down is obtained EIT remains, however....

Particle-in-cell studies of fast-ion slowing-down rates in cool tenuous magnetized plasma

Science.gov (United States)

Evans, Eugene S.; Cohen, Samuel A.; Welch, Dale R.

2018-04-01

We report on 3D-3V particle-in-cell simulations of fast-ion energy-loss rates in a cold, weakly-magnetized, weakly-coupled plasma where the electron gyroradius, ρe, is comparable to or less than the Debye length, λDe, and the fast-ion velocity exceeds the electron thermal velocity, a regime in which the electron response may be impeded. These simulations use explicit algorithms, spatially resolve ρe and λDe, and temporally resolve the electron cyclotron and plasma frequencies. For mono-energetic dilute fast ions with isotropic velocity distributions, these scaling studies of the slowing-down time, τs, versus fast-ion charge are in agreement with unmagnetized slowing-down theory; with an applied magnetic field, no consistent anisotropy between τs in the cross-field and field-parallel directions could be resolved. Scaling the fast-ion charge is confirmed as a viable way to reduce the required computational time for each simulation. The implications of these slowing down processes are described for one magnetic-confinement fusion concept, the small, advanced-fuel, field-reversed configuration device.

Shear wave velocity structure of the Anatolian Plate and surrounding regions using Ambient Noise Tomography

Science.gov (United States)

Delph, J. R.; Beck, S. L.; Zandt, G.; Biryol, C. B.; Ward, K. M.

2013-12-01

The Anatolian Plate consists of various lithospheric terranes amalgamated during the closure of the Tethys Ocean, and is currently extruding to the west in response to a combination of the collision of the Arabian plate in the east and the roll back of the Aegean subduction zone in the west. We used Ambient Noise Tomography (ANT) at periods structure of the Anatolian Plate. We computed a total of 13,779 unique cross-correlations using one sample-per-second vertical component broadband seismic data from 215 stations from 8 different networks over a period of 7 years to compute fundamental-mode Rayleigh wave dispersion curves following the method of Benson et al. (2007). We then inverted the dispersion data to calculate phase velocity maps for 11 periods from 8 s - 40 s throughout Anatolia and the Aegean regions (Barmin et al. 2001). Using smoothed Moho values derived from Vanacore et al. (2013) in our starting models, we inverted our dispersion curves using a linear least-squares iterative inversion scheme (Herrmann & Ammon 2004) to produce a 3-D shear-wave velocity model of the crust and uppermost mantle throughout Anatolia and the Aegean. We find a good correlation between our seismic shear wave velocities and paleostructures (suture zones) and modern deformation (basin formation and fault deformation). The most prominent crustal velocity contrasts occur across intercontinental sutures zones, resulting from the juxtaposition of the compositionally different basements of the amalgamated terranes. At shallow depths, seismic velocity contrasts correspond closely with surficial features. The Thrace, Cankiri and Tuz Golu basins, and accretionary complexes related to the closure of the Neotethys are characterized by slow shear wave velocities, while the Menderes and Kirsehir Massifs, Pontides, and Istanbul Zone are characterized by fast velocities. We find that the East Anatolia Plateau has slow shear-wave velocities, as expected due to high heat flow and active

The effect of groundwater fluctuations on the velocity pattern of slow-moving landslides

NARCIS (Netherlands)

Van Asch, T.W.J.; Malet, J.P.; Bogaard, T.A.

2009-01-01

Slow-moving landslides show complex mechanical and fluid interactions. They show among others non linear intrinsic viscosity of the shear zone, undrained loading effects and the generation of excess pore water pressure. The parameterization of hydrological and geomechanical factors by field and

Central Blood Pressure and Chronic Kidney Disease Progression

Directory of Open Access Journals (Sweden)

Debbie L. Cohen

2011-01-01

Full Text Available Hypertension, diabetes, and proteinuria are well-recognized risk factors for progressive kidney function loss. However, despite excellent antihypertensive and antidiabetic drug therapies, which also often lower urinary protein excretion, there remains a significant reservoir of patients with chronic kidney disease who are at high risk for progression to end-stage kidney disease. This has led to the search for less traditional cardiovascular risk factors that will help stratify patients at risk for more rapid kidney disease progression. Among these are noninvasive estimates of vascular structure and function. Arterial stiffness, manifested by the pulse wave velocity in the aorta, has been established in a number of studies as a significant risk factor for kidney disease progression and cardiovascular endpoints. Much less well studied in chronic kidney disease are measures of central arterial pressures. In this paper we cover the physiology behind the generation of the central pulse wave contour and the studies available using these approaches and conclude with some speculations on the rationale for why measurements of central pressure may be informative for the study of chronic kidney disease progression.

Estimated carotid-femoral pulse wave velocity has similar predictive value as measured carotid-femoral pulse wave velocity

DEFF Research Database (Denmark)

Olsen, Michael; Greve, Sara; Blicher, Marie

2016-01-01

OBJECTIVE: Carotid-femoral pulse wave velocity (cfPWV) adds significantly to traditional cardiovascular (CV) risk prediction, but is not widely available. Therefore, it would be helpful if cfPWV could be replaced by an estimated carotid-femoral pulse wave velocity (ePWV) using age and mean blood...... pressure and previously published equations. The aim of this study was to investigate whether ePWV could predict CV events independently of traditional cardiovascular risk factors and/or cfPWV. DESIGN AND METHOD: cfPWV was measured and ePWV calculated in 2366 apparently healthy subjects from four age...

Stochastic dynamic modeling of regular and slow earthquakes

Science.gov (United States)

Aso, N.; Ando, R.; Ide, S.

2017-12-01

Both regular and slow earthquakes are slip phenomena on plate boundaries and are simulated by a (quasi-)dynamic modeling [Liu and Rice, 2005]. In these numerical simulations, spatial heterogeneity is usually considered not only for explaining real physical properties but also for evaluating the stability of the calculations or the sensitivity of the results on the condition. However, even though we discretize the model space with small grids, heterogeneity at smaller scales than the grid size is not considered in the models with deterministic governing equations. To evaluate the effect of heterogeneity at the smaller scales we need to consider stochastic interactions between slip and stress in a dynamic modeling. Tidal stress is known to trigger or affect both regular and slow earthquakes [Yabe et al., 2015; Ide et al., 2016], and such an external force with fluctuation can also be considered as a stochastic external force. A healing process of faults may also be stochastic, so we introduce stochastic friction law. In the present study, we propose a stochastic dynamic model to explain both regular and slow earthquakes. We solve mode III problem, which corresponds to the rupture propagation along the strike direction. We use BIEM (boundary integral equation method) scheme to simulate slip evolution, but we add stochastic perturbations in the governing equations, which is usually written in a deterministic manner. As the simplest type of perturbations, we adopt Gaussian deviations in the formulation of the slip-stress kernel, external force, and friction. By increasing the amplitude of perturbations of the slip-stress kernel, we reproduce complicated rupture process of regular earthquakes including unilateral and bilateral ruptures. By perturbing external force, we reproduce slow rupture propagation at a scale of km/day. The slow propagation generated by a combination of fast interaction at S-wave velocity is analogous to the kinetic theory of gasses: thermal

Enhancing the sensitivity of slow light MZI biosensors through multi-hole defects

Science.gov (United States)

Qin, Kun; Zhao, Yiliang; Hu, Shuren; Weiss, Sharon M.

2018-02-01

We demonstrate enhanced detection sensitivity of a slow light Mach-Zehnder interferometer (MZI) sensor by incorporating multi-hole defects (MHDs). Slow light MZI biosensors with a one-dimensional photonic crystal in one arm have been previously shown to improve the performance of traditional MZI sensors based on the increased lightmatter interaction that takes place in the photonic crystal region of the structure. Introducing MHDs in the photonic crystal region increases the available surface area for molecular attachment and further increases the enhanced lightmatter interaction capability of slow light MZIs. The MHDs allow analyte to interact with a greater fraction of the guided wave in the MZI. For a slow light MHD MZI sensor with a 16 μm long sensing arm, a bulk sensitivity of 151,000 rad/RIU-cm is demonstrated experimentally, which is approximately two-fold higher than our previously reported slow light MZI sensors and thirteen-fold higher than traditional MZI biosensors with millimeter length sensing regions. For the label-free detection of nucleic acids, the slow light MZI with MHDs also exhibits a two-fold sensitivity improvement in experiment compared to the slow light MZI without MHDs. Because the detection sensitivity of slow light MHD MZIs scales with the length of the sensing arm, the tradeoff between detection limit and device size can be appropriately mitigated for different applications. All experimental results presented in this work are in good agreement with finite difference-time domain-calculations. Overall, the slow light MZI biosensors with MHDs are a promising platform for highly sensitive and multiplexed lab-on-chip systems.

Effect of Phase Transformations on Seismic Velocities

Science.gov (United States)

Weidner, D. J.; Li, L.; Whitaker, M.; Triplett, R.

2017-12-01

The radial velocity structure of the Earth consists of smooth variations of velocities with depth punctuated by abrupt changes of velocity, which are typically due to multivariant phase transformations, where high - low pressure phases can coexist. In this mixed phase region, both the effective shear and bulk moduli will be significantly reduced by the dynamic interaction of the propagating wave and the phase transition if the period of the wave is long enough relative to the kinetic time so that some of the transition can take place. In this presentation, we will give examples from both laboratory studies of phases transitions of Earth minerals and the calculated velocity profile based on our models. We focus on understanding the time limiting factor of the phase transformation in order to extrapolate laboratory results to Earth observations. Both the olivine to ringwoodite transition and KLB-1 partial melting are explored. We find that when the transformation requires diffusion, the kinetics are often slowed down considerably and as a result the diffusivity of atoms become the limiting factor of characteristic time. Specifically Fe-Mg exchange rate in the olivine-ringwoodite phase transition becomes the limiting factor that seismic waves are likely to sample. On the other hand, partial melting is an extremely fast phase transformation at seismic wave periods. We present evidence that ultrasonic waves, with a period of a few tens of nanoseconds, are slowed by the reduction of the effective elastic moduli in this case.

The lithospheric shear-wave velocity structure of Saudi Arabia: Young volcanism in an old shield

KAUST Repository

Tang, Zheng

2016-05-11

We investigate the lithospheric shear-wave velocity structure of Saudi Arabia by conducting H-κ stacking analysis and jointly inverting teleseismic P-receiver functions and fundamental-mode Rayleigh wave group velocities at 56 broadband stations deployed by the Saudi Geological Survey (SGS). The study region, the Arabian plate, is traditionally divided into the western Arabian shield and the eastern Arabian platform: The Arabian shield itself is a complicated mélange of crustal material, composed of several Proterozoic terrains separated by ophiolite-bearing suture zones and dotted by outcropping Cenozoic volcanic rocks (locally known as harrats). The Arabian platform is primarily covered by 8 to 10 km of Paleozoic, Mesozoic and Cenozoic sedimentary rocks. Our results reveal high Vp/Vs ratios in the region of Harrat Lunayyir, which are interpreted as solidified magma intrusions from old magmatic episodes in the shield. Our results also indicate slow velocities and large upper mantle lid temperatures below the southern and northern tips of the Arabian shield, when compared with the values obtained for the central shield. We argue that our inferred patterns of lid velocity and temperature are due to heating by thermal conduction from the Afar plume (and, possibly, the Jordan plume), and that volcanism in western Arabia may result from small-scale adiabatic ascent of magma diapirs.

FROM SLOW FOOD TO SLOW TOURISM

Directory of Open Access Journals (Sweden)

Bac Dorin Paul

2014-12-01

Full Text Available One of the effects of globalization is the faster pace of our lives. This rhythm can be noticed in all aspects of life: travel, work, shopping, etc. and it has serious negative effects. It has become common knowledge that stress and speed generate serious medical issues. Food and eating habits in the modern world have taken their toll on our health. However, some people took a stand and argued for a new kind of lifestyle. It all started in the field of gastronomy, where a new movement emerged – Slow Food, based on the ideas and philosophy of Carlo Petrini. Slow Food represents an important adversary to the concept of fast food, and is promoting local products, enjoyable meals and healthy food. The philosophy of the Slow Food movement developed in several directions: Cittaslow, slow travel and tourism, slow religion and slow money etc. The present paper will account the evolution of the concept and its development during the most recent years. We will present how the philosophy of slow food was applied in all the other fields it reached and some critical points of view. Also we will focus on the presence of the slow movement in Romania, although it is in a very early stage of development. The main objectives of the present paper are: to present the chronological and ideological evolution of the slow movement; to establish a clear separation of slow travel and slow tourism, as many mistake on for the other; to review the presence of the slow movement in Romania. Regarding the research methodology, information was gathered from relevant academic papers and books and also from interviews and discussions with local entrepreneurs. The research is mostly theoretical and empirical, as slow food and slow tourism are emerging research themes in academic circles.

Analysis of photosynthate translocation velocity and measurement of weighted average velocity in transporting pathway of crops

International Nuclear Information System (INIS)

Ge Cailin; Luo Shishi; Gong Jian; Zhang Hao; Ma Fei

1996-08-01

The translocation profile pattern of 14 C-photosynthate along the transporting pathway in crops were monitored by pulse-labelling a mature leaf with 14 CO 2 . The progressive spreading of translocation profile pattern along the sheath or stem indicates that the translocation of photosynthate along the sheath or stem proceed with a range of velocities rather than with just a single velocity. The method for measuring the weighted average velocity of photosynthate translocation along the sheath or stem was established in living crops. The weighted average velocity and the maximum velocity of photosynthate translocation along the sheath in rice and maize were measured actually. (4 figs., 3 tabs.)

Impact of ADMA, endothelial progenitor cells and traditional cardiovascular risk factors on pulse wave velocity among prediabetic individuals

Directory of Open Access Journals (Sweden)

Protopsaltis Ioannis

2012-11-01

Full Text Available Abstract Background Central arterial stiffness represents a well-established predictor of cardiovascular disease. Decreased circulating endothelial progenitor cells (EPCs, increased asymmetric dimethyl-arginine (ADMA levels, traditional cardiovascular risk factors and insulin resistance have all been associated with increased arterial stiffness. The correlations of novel and traditional cardiovascular risk factors with central arterial stiffness in prediabetic individuals were investigated in the present study. Methods The study population consisted of 53 prediabetic individuals. Individuals were divided into groups of isolated impaired fasting glucose (IFG, isolated impaired glucose tolerance (IGT and combined IGT-IFG. Age, sex, family history of diabetes, smoking history, body mass index (BMI, waist to hip ratio (WHR, waist circumference (WC, blood pressure, lipid profile, levels of high sensitive C-reactive protein (hsCRP, glomerular filtration rate (GFR, and history of antihypertensive or statin therapy were obtained from all participants. Insulin resistance was evaluated using the Homeostatic Model Assessment (HOMA-IR. Carotid -femoral pulse wave velocity was used as an index of arterial stiffness. Circulating EPC count and ADMA serum levels were also determined. Results Among studied individuals 30 (56.6% subjects were diagnosed with isolated IFG, 9 (17% with isolated IGT (17% and 14 with combined IFG-IGT (26.4%. In univariate analysis age, mean blood pressure, fasting glucose, total cholesterol, LDL cholesterol, and ADMA levels positively correlated with pulse-wave velocity while exercise and GFR correlated negatively. EPC count did not correlate with PWV. In multivariate stepwise regression analysis PWV correlated independently and positively with LDL-Cholesterol (low density lipoprotein and ADMA levels and negatively with exercise. Conclusions Elevated ADMA and LDL-C levels are strongly associated with increased arterial stiffness among

Vascular care in patients with Alzheimer disease with cerebrovascular lesions slows progression of white matter lesions on MRI: the evaluation of vascular care in Alzheimer's disease (EVA) study.

Science.gov (United States)

Richard, Edo; Gouw, Alida A; Scheltens, Philip; van Gool, Willem A

2010-03-01

White matter lesions (WMLs) and cerebral infarcts are common findings in Alzheimer disease and may contribute to dementia severity. WMLs and lacunar infarcts may provide a potential target for intervention strategies. This study assessed whether multicomponent vascular care in patients with Alzheimer disease with cerebrovascular lesions slows progression of WMLs and prevents occurrence of new infarcts. A randomized controlled clinical trial, including 123 subjects, compared vascular care with standard care in patients with Alzheimer disease with cerebrovascular lesions on MRI. Progression of WMLs, lacunes, medial temporal lobe atrophy, and global cortical atrophy were semiquantitatively scored after 2-year follow-up. Sixty-five subjects (36 vascular care, 29 standard care) had a baseline and a follow-up MRI and in 58 subjects, a follow-up scan could not be obtained due to advanced dementia or death. Subjects in the vascular care group had less progression of WMLs as measured with the WML change score (1.4 versus 2.3, P=0.03). There was no difference in the number of new lacunes or change in global cortical atrophy or medial temporal lobe atrophy between the 2 groups. Vascular care in patients with Alzheimer disease with cerebrovascular lesions slows progression of WMLs. Treatment aimed at vascular risk factors in patients with early Alzheimer disease may be beneficial, possibly in an even earlier stage of the disease.

Impaired left ventricular systolic function and increased brachial-ankle pulse-wave velocity are independently associated with rapid renal function progression.

Science.gov (United States)

Chen, Szu-Chia; Lin, Tsung-Hsien; Hsu, Po-Chao; Chang, Jer-Ming; Lee, Chee-Siong; Tsai, Wei-Chung; Su, Ho-Ming; Voon, Wen-Chol; Chen, Hung-Chun

2011-09-01

Heart failure and increased arterial stiffness are associated with declining renal function. Few studies have evaluated the association between left ventricular ejection fraction (LVEF) and brachial-ankle pulse-wave velocity (baPWV) and renal function progression. The aim of this study was to assess whether LVEFfunction was estimated by eGFR slope. The renal end point was defined as ≥25% decline in eGFR. Clinical and echocardiographic parameters were compared and analyzed. After a multivariate analysis, serum hematocrit was positively associated with eGFR slope, and diabetes mellitus, baPWV (P=0.031) and LVEFfunction decline and progression to the renal end point.

Precursory changes in seismic velocity for the spectrum of earthquake failure modes

Science.gov (United States)

Scuderi, M.M.; Marone, C.; Tinti, E.; Di Stefano, G.; Collettini, C.

2016-01-01

Temporal changes in seismic velocity during the earthquake cycle have the potential to illuminate physical processes associated with fault weakening and connections between the range of fault slip behaviors including slow earthquakes, tremor and low frequency earthquakes1. Laboratory and theoretical studies predict changes in seismic velocity prior to earthquake failure2, however tectonic faults fail in a spectrum of modes and little is known about precursors for those modes3. Here we show that precursory changes of wave speed occur in laboratory faults for the complete spectrum of failure modes observed for tectonic faults. We systematically altered the stiffness of the loading system to reproduce the transition from slow to fast stick-slip and monitored ultrasonic wave speed during frictional sliding. We find systematic variations of elastic properties during the seismic cycle for both slow and fast earthquakes indicating similar physical mechanisms during rupture nucleation. Our data show that accelerated fault creep causes reduction of seismic velocity and elastic moduli during the preparatory phase preceding failure, which suggests that real time monitoring of active faults may be a means to detect earthquake precursors. PMID:27597879

End-systolic stress-velocity relation and circumferential fiber velocity shortening for analysing left ventricular function in mice

Energy Technology Data Exchange (ETDEWEB)

Fayssoil, A. [Cardiologie, Hopital europeen Georges Pompidou, 20, rue le blanc, Paris (France)], E-mail: fayssoil2000@yahoo.fr; Renault, G. [CNRS UMR 8104, Inserm, U567, Institut Cochin, Universite Paris Descartes, Paris (France); Fougerousse, F. [Genethon, RD, Evry (France)

2009-08-15

Traditionally, analysing left ventricular (LV) performance relies on echocardiography by evaluating shortening fraction (SF) in mice. SF is influenced by load conditions. End-systolic stress-velocity (ESSV) relation and circumferential fiber velocity (VcF) shortening are more relevant parameters for evaluating systolic function regardless load conditions particularly in mice's models of heart failure.

The Potential of/for 'Slow': Slow Tourists and Slow Destinations

Directory of Open Access Journals (Sweden)

J. Guiver

2016-05-01

Full Text Available Slow tourism practices are nothing new; in fact, they were once the norm and still are for millions of people whose annual holiday is spent camping, staying in caravans, rented accommodation, with friends and relations or perhaps in a second home, who immerse themselves in their holiday environment, eat local food, drink local wine and walk or cycle around the area. So why a special edition about slow tourism? Like many aspects of life once considered normal (such as organic farming or free-range eggs, the emergence of new practices has highlighted differences and prompted a re-evaluation of once accepted practices and values. In this way, the concept of ‘slow tourism’ has recently appeared as a type of tourism that contrasts with many contemporary mainstream tourism practices. It has also been associated with similar trends already ‘branded’ slow: slow food and cittaslow (slow towns and concepts such as mindfulness, savouring and well-being.

Slow waves in microchannel metal waveguides and application to particle acceleration

OpenAIRE

L. C. Steinhauer; W. D. Kimura

2003-01-01

Conventional metal-wall waveguides support waveguide modes with phase velocities exceeding the speed of light. However, for infrared frequencies and guide dimensions of a fraction of a millimeter, one of the waveguide modes can have a phase velocity equal to or less than the speed of light. Such a metal microchannel then acts as a slow-wave structure. Furthermore, if it is a transverse magnetic mode, the electric field has a component along the direction of propagation. Therefore, a strong ex...

Broadband slow light in one-dimensional logically combined photonic crystals.

Science.gov (United States)

Alagappan, G; Png, C E

2015-01-28

Here, we demonstrate the broadband slow light effects in a new family of one dimensional photonic crystals, which are obtained by logically combining two photonic crystals of slightly different periods. The logical combination slowly destroys the original translational symmetries of the individual photonic crystals. Consequently, the Bloch modes of the individual photonic crystals with different wavevectors couple with each other, creating a vast number of slow modes. Specifically, we describe a photonic crystal architecture that results from a logical "OR" mixture of two one dimensional photonic crystals with a periods ratio of r = R/(R - 1), where R > 2 is an integer. Such a logically combined architecture, exhibits a broad region of frequencies in which a dense number of slow modes with varnishing group velocities, appear naturally as Bloch modes.

Lead Slowing Down Spectrometer Status Report

International Nuclear Information System (INIS)

Warren, Glen A.; Anderson, Kevin K.; Bonebrake, Eric; Casella, Andrew M.; Danon, Yaron; Devlin, M.; Gavron, Victor A.; Haight, R.C.; Imel, G.R.; Kulisek, Jonathan A.; O'Donnell, J.M.; Weltz, Adam

2012-01-01

This report documents the progress that has been completed in the first half of FY2012 in the MPACT-funded Lead Slowing Down Spectrometer project. Significant progress has been made on the algorithm development. We have an improve understanding of the experimental responses in LSDS for fuel-related material. The calibration of the ultra-depleted uranium foils was completed, but the results are inconsistent from measurement to measurement. Future work includes developing a conceptual model of an LSDS system to assay plutonium in used fuel, improving agreement between simulations and measurement, design of a thorium fission chamber, and evaluation of additional detector techniques.

Mass Flux and Terminal Velocities of Magnetically Driven Jets from Accretion Disks

Science.gov (United States)

Kudoh, Takahiro; Shibata, Kazunari

1995-10-01

In order to investigate astrophysical jets from accretion disks, we solve 1.5-dimensional steady MHD equations for a wide range of parameters, assuming the shape of poloidal magnetic field lines. We include a thermal effect to obtain the relation between the mass flux of the jet and the magnetic energy at the disk, although the jet is mainly accelerated by the magnetic force. It is found that the mass flux of the jets ( M dot ) is dependent on the magnetic energy at the disk surface, i.e., M dot ~ (rho Aa|Bp/B|)_{{slow}} ~ (rho Aa|Bp/Bphi|)_{{slow}} ~ Ealpha_{{mg}} [where rho is the density, a is the sound velocity, A is the cross section of the magnetic flux, B = (B2p + B2phi)^{1/2} , Bp and B phi are the poloidal and toroidal magnetic field strength, respectively, Emg is the magnetic energy in unit of the gravitational energy at the disk surface, and the suffix "slow" denotes the value at a slow point], when the magnetic energy is not too large. The parameter alpha increases from 0 to 0.5 with decreasing magnetic energy. Since the scaling law of Michel's minimum energy solution nearly holds in the magnetically driven flows, the dependence of the terminal velocity on the magnetic energy becomes weaker than had been expected, i.e., v_∞ ~ E^{(1-alpha)/3}_{{mg}} . It is shown that the terminal velocity of the jet is an order of Keplerian velocity at the footpoint of the jets for a wide range of values of Emg expected for accretion disks in star-forming regions and active galactic nuclei. We argue that the mass-loss rates observed in the star-forming regions would constrain the magnetic energies at the disk surfaces.

Slowing techniques for loading a magneto-optical trap of CaF molecules

Science.gov (United States)

Truppe, Stefan; Fitch, Noah; Williams, Hannah; Hambach, Moritz; Sauer, Ben; Hinds, Ed; Tarbutt, Mike

2016-05-01

Ultracold molecules in a magneto-optical trap (MOT) are useful for testing fundamental physics and studying strongly-interacting quantum systems. With experiments starting with a relatively fast (50-200 m/s) buffer-gas beam, a primary concern is decelerating molecules to below the MOT capture velocity, typically 10 m/s. Direct laser cooling, where the molecules are slowed via momentum transfer from a chirped counter-propagating narrowband laser, is a natural choice. However, chirping the cooling and repump lasers requires precise control of multiple laser frequencies simultaneously. Another approach, called ``white-light slowing'' uses a broadband laser such that all fast molecules in the beam are decelerated. By addressing numerous velocities no chirping is needed. Unfortunately, both techniques have significant losses as molecules are transversely heated during the optical cycling. Ideally, the slowing method would provide simultaneous deceleration and transverse guiding. A newly developed technique, called Zeeman-Sisyphus deceleration, is potentially capable of both. Using permanent magnets and optical pumping, the number of scattered photons is reduced, lessening transverse heating and relaxing the repump requirements. Here we compare all three options for CaF.

Structure of slow shocks in a magnetized plasma with heat conduction

International Nuclear Information System (INIS)

Tsai, C.L.; Tsai, R.H.; Wu, B.H.; Lee, L.C.

2002-01-01

The structure of slow shocks in the presence of a heat conduction parallel to the local magnetic field is simulated from the set of magnetohydrodynamic equations. In this study, a pair of slow shocks is formed through the evolution of a current sheet initiated by the presence of a normal magnetic field. It is found that the slow shock consists of two parts: The isothermal main shock and foreshock. Significant jumps in plasma density, velocity and magnetic field occur across the main shock, but the temperature is found to be continuous across the main shock. The foreshock is featured by a smooth temperature variation and is formed due to the heat flow from downstream to upstream region. The plasma density downstream of the main shock decreases with time, while the downstream temperature increases with time, keeping the downstream pressure constant. It is shown that the jumps in plasma density, pressure, velocity, and magnetic field across the main shock are determined by the set of modified isothermal Rankine-Hugoniot conditions. It is also found that a jump in the temperature gradient is present across the main shock in order to satisfy the energy conservation. The present results can be applied to the heating in the solar corona and solar wind

Direct imaging of slow, stored and stationary EIT polaritons

Science.gov (United States)

Campbell, Geoff T.; Cho, Young-Wook; Su, Jian; Everett, Jesse; Robins, Nicholas; Lam, Ping Koy; Buchler, Ben

2017-09-01

Stationary and slow light effects are of great interest for quantum information applications. Using laser-cooled Rb87 atoms, we performed side imaging of our atomic ensemble under slow and stationary light conditions, which allows direct comparison with numerical models. The polaritons were generated using electromagnetically induced transparency (EIT), with stationary light generated using counter-propagating control fields. By controlling the power ratio of the two control fields, we show fine control of the group velocity of the stationary light. We also compare the dynamics of stationary light using monochromatic and bichromatic control fields. Our results show negligible difference between the two situations, in contrast to previous work in EIT-based systems.

Simulating the Evolving Behavior of Secondary Slow Slip Fronts

Science.gov (United States)

Peng, Y.; Rubin, A. M.

2017-12-01

High-resolution tremor catalogs of slow slip events reveal secondary slow slip fronts behind the main front that repetitively occupy the same source area during a single episode. These repetitive fronts are most often observed in regions with high tremor density. Their recurrence intervals gradually increase from being too short to be tidally modulated (tens of minutes) to being close to tidal periods (about 12 or 24 hours). This could be explained by a decreasing loading rate from creep in the surrounding regions (with few or no observable tremor events) as the main front passes by. As the recurrence intervals of the fronts increase, eventually they lock in on the tidal periods. We attempt to simulate this numerically using a rate-and-state friction law that transitions from velocity-weakening at low slip speeds to velocity strengthening at high slip speeds. Many small circular patches with a cutoff velocity an order of magnitude higher than that of the background are randomly placed on the fault, in order to simulate the average properties of the high-density tremor zone. Preliminary results show that given reasonable parameters, this model produces similar propagation speeds of the forward-migrating main front inside and outside the high-density tremor zone, consistent with observations. We will explore the behavior of the secondary fronts that arise in this model, in relation to the local density of the small tremor-analog patches, the overall geometry of the tremor zone and the tides.

Eclogitization of the Subducted Oceanic Crust and Its Implications for the Mechanism of Slow Earthquakes

Science.gov (United States)

Wang, Xinyang; Zhao, Dapeng; Suzuki, Haruhiko; Li, Jiabiao; Ruan, Aiguo

2017-12-01

The generating mechanism and process of slow earthquakes can help us to better understand the seismogenic process and the petrological evolution of the subduction system, but they are still not very clear. In this work we present robust P and S wave tomography and Poisson's ratio images of the subducting Philippine Sea Plate beneath the Kii peninsula in Southwest Japan. Our results clearly reveal the spatial extent and variation of a low-velocity and high Poisson's ratio layer which is interpreted as the remnant of the subducted oceanic crust. The low-velocity layer disappears at depths >50 km, which is attributed to crustal eclogitization and consumption of fluids. The crustal eclogitization and destruction of the impermeable seal play a key role in the generation of slow earthquakes. The Moho depth of the overlying plate is an important factor affecting the depth range of slow earthquakes in warm subduction zones due to the transition of interface permeability from low to high there. The possible mechanism of the deep slow earthquakes is the dehydrated oceanic crustal rupture and shear slip at the transition zone in response to the crustal eclogitization and the temporal stress/strain field. A potential cause of the slow event gap existing beneath easternmost Shikoku and the Kii channel is the premature rupture of the subducted oceanic crust due to the large tensional force.

Slowing down the speed of light using an electromagnetically-induced-transparency mechanism in a modified reservoir

Science.gov (United States)

Liu, Ronggang; Liu, Tong; Wang, Yingying; Li, Yujie; Gai, Bingzheng

2017-11-01

We propose an effective method to achieve extremely slow light by using both the mechanism of electromagnetically induced transparency (EIT) and the localization of a coupled cavity waveguide (CCW). Based on quantum mechanics theory and the dispersion relation of a CCW, we derive a group-velocity formula that reveals both the effects of the EIT and CCW. Results show that ultralow light velocity at the order of several meters per second or even static light, could be obtained feasibly. In comparison with the EIT mechanism in a background of vacuum, this proposed method is more effective and realistic to achieve extremely slow light. And it exhibits potential values in the field of light storage.

Changes in Sprint and Jump Performances After Traditional, Plyometric, and Combined Resistance Training in Male Youth Pre- and Post-Peak Height Velocity.

Science.gov (United States)

Lloyd, Rhodri S; Radnor, John M; De Ste Croix, Mark B A; Cronin, John B; Oliver, Jon L

2016-05-01

The purpose of this study was to compare the effectiveness of 6-week training interventions using different modes of resistance (traditional strength, plyometric, and combined training) on sprinting and jumping performances in boys before and after peak height velocity (PHV). Eighty school-aged boys were categorized into 2 maturity groups (pre- or post-PHV) and then randomly assigned to (a) plyometric training, (b) traditional strength training, (c) combined training, or (d) a control group. Experimental groups participated in twice-weekly training programs for 6 weeks. Acceleration, maximal running velocity, squat jump height, and reactive strength index data were collected pre- and postintervention. All training groups made significant gains in measures of sprinting and jumping irrespective of the mode of resistance training and maturity. Plyometric training elicited the greatest gains across all performance variables in pre-PHV children, whereas combined training was the most effective in eliciting change in all performance variables for the post-PHV cohort. Statistical analysis indicated that plyometric training produced greater changes in squat jump and acceleration performances in the pre-PHV group compared with the post-PHV cohort. All other training responses between pre- and post-PHV cohorts were not significant and not clinically meaningful. The study indicates that plyometric training might be more effective in eliciting short-term gains in jumping and sprinting in boys who are pre-PHV, whereas those who are post-PHV may benefit from the additive stimulus of combined training.

Slow slip phenomena in Cascadia from 2007 and beyond: a review

Science.gov (United States)

Gomberg, Joan; ,

2010-01-01

Recent technological advances combined with more detailed analyses of seismologic and geodetic observations have fundamentally changed our understanding of the ways in which tectonic stresses arising from plate motions are accommodated by slip on faults. The traditional view that relative plate motions are accommodated by a simple cycle of stress accumulation and release on “locked” plate-boundary faults has been revolutionized by the serendipitous discovery and recognition of the significance of slow-slip phenomena, mostly in the deeper reaches of subduction zones. The Cascadia subduction zone, located in the Pacific Northwest of the conterminous United States and adjacent Canada, is an archetype of exploration and learning about slow-slip phenomena. These phenomena are manifest as geodetically observed aseismic transient deformations accompanied by a previously unrecognized class of seismic signals. Although secondary failure processes may be involved in generating the seismic signals, the primary origins of both aseismic and seismic phenomena appear to be episodic fault slip, probably facilitated by fluids, on a plate interface that is critically stressed or weakened. In Cascadia, this transient slip evolves more slowly and over more prolonged durations relative to the slip in earthquakes, and it occurs between the 30- and 40-km-depth contours of the plate interface where information was previously elusive. Although there is some underlying organization that relaxes nearly all the accrued plate-motion stresses along the entirety of Cascadia, we now infer that slow slip evolves in complex patterns indicative of propagating stress fronts. Our new understanding provides key constraints not only on the region where the slow slip originates, but also on the probable characteristics of future megathrust earthquakes in Cascadia. Herein, we review the most significant scientific issues and progress related to understanding slow-slip phenomena in Cascadia and

Possible mechanisms underlying slow component of V̇O2 on-kinetics in skeletal muscle.

Science.gov (United States)

Korzeniewski, Bernard; Zoladz, Jerzy A

2015-05-15

A computer model of a skeletal muscle bioenergetic system is used to study the background of the slow component of oxygen consumption V̇O2 on-kinetics in skeletal muscle. Two possible mechanisms are analyzed: inhibition of ATP production by anaerobic glycolysis by progressive cytosol acidification (together with a slow decrease in ATP supply by creatine kinase) and gradual increase of ATP usage during exercise of constant power output. It is demonstrated that the former novel mechanism is potent to generate the slow component. The latter mechanism further increases the size of the slow component; it also moderately decreases metabolite stability and has a small impact on muscle pH. An increase in anaerobic glycolysis intensity increases the slow component, elevates cytosol acidification during exercise, and decreases phosphocreatine and Pi stability, although slightly increases ADP stability. A decrease in the P/O ratio (ATP molecules/O2 molecules) during exercise cannot also be excluded as a relevant mechanism, although this issue requires further study. It is postulated that both the progressive inhibition of anaerobic glycolysis by accumulating protons (together with a slow decrease of the net creatine kinase reaction rate) and gradual increase of ATP usage during exercise, and perhaps a decrease in P/O, contribute to the generation of the slow component of the V̇O2 on-kinetics in skeletal muscle. Copyright © 2015 the American Physiological Society.

Lower Mantle S-wave Velocity Model under the Western United States

Science.gov (United States)

Nelson, P.; Grand, S. P.

2016-12-01

Deep mantle plumes created by thermal instabilities at the core-mantle boundary has been an explanation for intraplate volcanism since the 1970's. Recently, broad slow velocity conduits in the lower mantle underneath some hotspots have been observed (French and Romanowicz, 2015), however the direct detection of a classical thin mantle plume using seismic tomography has remained elusive. Herein, we present a seismic tomography technique designed to image a deep mantle plume under the Yellowstone Hotspot located in the western United States utilizing SKS and SKKS waves in conjunction with finite frequency tomography. Synthetic resolution tests show the technique can resolve a 235 km diameter lower mantle plume with a 1.5% Gaussian velocity perturbation even if a realistic amount of random noise is added to the data. The Yellowstone Hotspot presents a unique opportunity to image a thin plume because it is the only hotspot with a purported deep origin that has a large enough aperture and density of seismometers to accurately sample the lower mantle at the length scales required to image a plume. Previous regional tomography studies largely based on S wave data have imaged a cylindrically shaped slow anomaly extending down to 900km under the hotspot, however they could not resolve it any deeper (Schmandt et al., 2010; Obrebski et al., 2010).To test if the anomaly extends deeper, we measured and inverted over 40,000 SKS and SKKS waves' travel times in two frequency bands recorded at 2400+ stations deployed during 2006-2012. Our preliminary model shows narrow slow velocity anomalies in the lower mantle with no fast anomalies. The slow anomalies are offset from the Yellowstone hotspot and may be diapirs rising from the base of the mantle.

Jovian cloud structure and velocity fields

International Nuclear Information System (INIS)

Mitchell, J.L.; Terrile, R.J.; Collins, S.A.; Smith, B.A.; Muller, J.P.; Ingersoll, A.P.; Hunt, G.E.; Beebe, R.F.

1979-01-01

A regional comparison of the cloud structures and velocity fields (meridional as well as zonal velocities) in the jovian atmosphere (scales > 200 km) as observed by the Voyager 1 imaging system is given. It is shown that although both hemispheres of Jupiter show similar patterns of diminishing and alternating eastward and westward jets as one progresses polewards, there is a pronounced asymmetry in the structural appearance of the two hemispheres. (UK)

Controlling myopia progression in children and adolescents

Directory of Open Access Journals (Sweden)

Smith MJ

2015-08-01

Full Text Available Molly J Smith, Jeffrey J WallineThe Ohio State University College of Optometry, Columbus, OH, USAAbstract: Myopia is a common disorder, affecting approximately one-third of the US population and over 90% of the population in some East Asian countries. High amounts of myopia are associated with an increased risk of sight-threatening problems, such as retinal detachment, choroidal degeneration, cataracts, and glaucoma. Slowing the progression of myopia could potentially benefit millions of children in the USA. To date, few strategies used for myopia control have proven to be effective. Treatment options such as undercorrection of myopia, gas permeable contact lenses, and bifocal or multifocal spectacles have all been proven to be ineffective for myopia control, although one recent randomized clinical trial using executive top bifocal spectacles on children with progressive myopia has shown to decrease the progression to nearly half of the control subjects. The most effective methods are the use of orthokeratology contact lenses, soft bifocal contact lenses, and topical pharmaceutical agents such as atropine or pirenzepine. Although none of these modalities are US Food and Drug Administration-approved to slow myopia progression, they have been shown to slow the progression by approximately 50% with few risks. Both orthokeratology and soft bifocal contact lenses have shown to slow myopia progression by slightly less than 50% in most studies. Parents and eye care practitioners should work together to determine which modality may be best suited for a particular child. Topical pharmaceutical agents such as anti-muscarinic eye drops typically lead to light sensitivity and poor near vision. The most effective myopia control is provided by atropine, but is rarely prescribed due to the side effects. Pirenzepine provides myopia control with little light sensitivity and few near-vision problems, but it is not yet commercially available as an eye drop or

Frequency of gamma oscillations in humans is modulated by velocity of visual motion

Science.gov (United States)

Butorina, Anna V.; Sysoeva, Olga V.; Prokofyev, Andrey O.; Nikolaeva, Anastasia Yu.; Stroganova, Tatiana A.

2015-01-01

Gamma oscillations are generated in networks of inhibitory fast-spiking (FS) parvalbumin-positive (PV) interneurons and pyramidal cells. In animals, gamma frequency is modulated by the velocity of visual motion; the effect of velocity has not been evaluated in humans. In this work, we have studied velocity-related modulations of gamma frequency in children using MEG/EEG. We also investigated whether such modulations predict the prominence of the “spatial suppression” effect (Tadin D, Lappin JS, Gilroy LA, Blake R. Nature 424: 312-315, 2003) that is thought to depend on cortical center-surround inhibitory mechanisms. MEG/EEG was recorded in 27 normal boys aged 8–15 yr while they watched high-contrast black-and-white annular gratings drifting with velocities of 1.2, 3.6, and 6.0°/s and performed a simple detection task. The spatial suppression effect was assessed in a separate psychophysical experiment. MEG gamma oscillation frequency increased while power decreased with increasing velocity of visual motion. In EEG, the effects were less reliable. The frequencies of the velocity-specific gamma peaks were 64.9, 74.8, and 87.1 Hz for the slow, medium, and fast motions, respectively. The frequency of the gamma response elicited during slow and medium velocity of visual motion decreased with subject age, whereas the range of gamma frequency modulation by velocity increased with age. The frequency modulation range predicted spatial suppression even after controlling for the effect of age. We suggest that the modulation of the MEG gamma frequency by velocity of visual motion reflects excitability of cortical inhibitory circuits and can be used to investigate their normal and pathological development in the human brain. PMID:25925324

Recent progress in the joint velocity-scalar PDF method

Science.gov (United States)

Anand, M. S.

1995-01-01

This viewgraph presentation discusses joint velocity-scalar PDF method; turbulent combustion modeling issues for gas turbine combustors; PDF calculations for a recirculating flow; stochastic dissipation model; joint PDF calculations for swirling flows; spray calculations; reduced kinetics/manifold methods; parallel processing; and joint PDF focus areas.

Streaming Velocities and the Baryon Acoustic Oscillation Scale.

Science.gov (United States)

Blazek, Jonathan A; McEwen, Joseph E; Hirata, Christopher M

2016-03-25

At the epoch of decoupling, cosmic baryons had supersonic velocities relative to the dark matter that were coherent on large scales. These velocities subsequently slow the growth of small-scale structure and, via feedback processes, can influence the formation of larger galaxies. We examine the effect of streaming velocities on the galaxy correlation function, including all leading-order contributions for the first time. We find that the impact on the baryon acoustic oscillation (BAO) peak is dramatically enhanced (by a factor of ∼5) over the results of previous investigations, with the primary new effect due to advection: if a galaxy retains memory of the primordial streaming velocity, it does so at its Lagrangian, rather than Eulerian, position. Since correlations in the streaming velocity change rapidly at the BAO scale, this advection term can cause a significant shift in the observed BAO position. If streaming velocities impact tracer density at the 1% level, compared to the linear bias, the recovered BAO scale is shifted by approximately 0.5%. This new effect, which is required to preserve Galilean invariance, greatly increases the importance of including streaming velocities in the analysis of upcoming BAO measurements and opens a new window to the astrophysics of galaxy formation.

Influence of tungsten fiber’s slow drift on the measurement of G with angular acceleration method

Energy Technology Data Exchange (ETDEWEB)

Luo, Jie; Wu, Wei-Huang; Zhan, Wen-Ze [School of Mechanical Engineering and Electronic Information, China University of Geosciences, Wuhan 430074 (China); Xue, Chao [MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Physics and Astronomy, Sun Yat-sen University, Guangzhou 510275 (China); Shao, Cheng-Gang, E-mail: cgshao@mail.hust.edu.cn; Wu, Jun-Fei [MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Milyukov, Vadim [Sternberg Astronomical Institute, Lomonosov Moscow State University, Moscow 119992 (Russian Federation)

2016-08-15

In the measurement of the gravitational constant G with angular acceleration method, the equilibrium position of torsion pendulum with tungsten fiber undergoes a linear slow drift, which results in a quadratic slow drift on the angular velocity of the torsion balance turntable under feedback control unit. The accurate amplitude determination of the useful angular acceleration signal with known frequency is biased by the linear slow drift and the coupling effect of the drifting equilibrium position and the room fixed gravitational background signal. We calculate the influences of the linear slow drift and the complex coupling effect on the value of G, respectively. The result shows that the bias of the linear slow drift on G is 7 ppm, and the influence of the coupling effect is less than 1 ppm.

Self-collimated slow sound in sonic crystals

International Nuclear Information System (INIS)

Kaya, Olgun Adem; Cicek, Ahmet; Ulug, Bulent

2012-01-01

Self-collimated slow-sound propagation in a two-dimensional rectangular sonic crystal composed of elliptical scatterers in air is numerically demonstrated. The group velocity at the centre and the edges of the fourth acoustic band is reduced to 45 m s -1 and 30 m s -1 , corresponding to 1/8 and 1/12 of the speed of sound in air, respectively. Elimination of omni-directional reflections encountered in linear waveguides and the reduction of group-velocity dispersion at the mid-band frequencies lead to preservation of pulse shape and amplitude upon traversal of the sonic crystal. Wave transmission is increased from approximately -20 to -2.5 dB, with almost an order of magnitude enhancement, via injector layers optimized through a pattern search algorithm. Self-collimating performance of the system is not degraded under oblique incidence, except for pulse broadening due to increased effective source width.

On novel mechanisms of slow ion induced electron emission

International Nuclear Information System (INIS)

Eder, H.

2000-09-01

The present work has contributed in new ways to the field of slow ion induced electron emission. First, measurements of the total electron yield γ for impact of slow singly and multiply charged ions on atomically clean polycrystalline gold and graphite have been made. The respective yields were determined by current measurements and measurements of the electron number statistics. A new mechanism for kinetic emission (KE) below the so called 'classical threshold' was found and discussed. For a given ion species and impact velocity a slight decrease of the yields was found for ion charge state q = 1 toward 3, but no significant differences in KE yields for higher q values. Comparison of the results from gold and graphite showed overall similar behavior, but for C+ a relatively strong difference was observed and ascribed to more effective electron promotion in the C-C- than in the C-Au system. Secondly, for the very specific system H0 on LiF we investigated single electron excitation processes under grazing incidence conditions. In this way long-range interactions of hydrogen atoms with the ionic crystal surface could be probed. Position- and velocity-dependent electron production rates were found which indicate that an electron promotion mechanism is responsible for the observed electron emission. Thirdly, in order to investigate the importance of plasmon excitation and -decay in slow ion induced electron emission, measurements of electron energy distributions from impact of singly and doubly charged ions on poly- and monocrystalline aluminum surfaces were performed. From the results we conclude that direct plasmon excitation by slow ions occurs due to the potential energy of the projectile in a quasi-resonant fashion. The highest relative plasmon intensities were found for impact of 5 keV Ne+ on Al(111) with 5 % of the total yield. For impact of H + and H 2 + characteristical differences were observed for Al(111) and polycrystalline aluminum. We show that

Comparison of slowness profiles of lamb wave with elastic moduli and crystal structure in single crystalline silicon wafers

Energy Technology Data Exchange (ETDEWEB)

Min, Young Jae; Yun, Gyeong Won; Kim, Kyung Min; Roh, Yuji; Kim, Young H. [Applied Acoustics Lab, Korea Science Academy of KAIST, Busan (Korea, Republic of)

2016-02-15

Single crystalline silicon wafers having (100), (110), and (111) directions are employed as specimens for obtaining slowness profiles. Leaky Lamb waves (LLW) from immersed wafers were detected by varying the incident angles of the specimens and rotating the specimens. From an analysis of LLW signals for different propagation directions and phase velocities of each specimen, slowness profiles were obtained, which showed a unique symmetry with different symmetric axes. Slowness profiles were compared with elastic moduli of each wafer. They showed the same symmetries as crystal structures. In addition, slowness profiles showed expected patterns and values that can be inferred from elastic moduli. This implies that slowness profiles can be used to examine crystal structures of anisotropic solids.

[Research progress on potential liver toxic components in traditional Chinese medicine].

Science.gov (United States)

Wu, Hao; Zhong, Rong-Ling; Xia, Zhi; Huang, Hou-Cai; Zhong, Qing-Xiang; Feng, Liang; Song, Jie; Jia, Xiao-Bin

2016-09-01

In recent years, the proportion of traditional Chinese medicine in scientific research and its clinical use increased gradually. The research result also becomes more and more valuable, but in the process of using traditional Chinese medicine, it also needs to pay more attention. With the gradual deepening of the toxicity of traditional Chinese medicine, some traditional Chinese medicines have also been found to have the potential toxicity, with the exception of some traditional toxicity Chinese medicine. Traditional Chinese medicine in the growth, processing, processing, transportation and other aspects of pollution or deterioration will also cause the side effects to the body. Clinical practice should be based on the theory of traditional Chinese medicine to guide rational drug use and follow the symptomatic medication, the principle of proper compatibility. The constitution of the patients are different, except for a few varieties of traditional Chinese medicines are natural herbs with hepatotoxicity, liver toxicity of most of the traditional Chinese medicine has idiosyncratic features. The liver plays an important role in drug metabolism. It is easy to be damaged by drugs. Therefore, the study of traditional Chinese medicine potential liver toxicity and its toxic components has become one of the basic areas of traditional Chinese medicine research. Based on the review of the literatures, this paper summarizes the clinical classification of liver toxicity, the pathogenesis of target cell injury, and systematically summarizes the mechanism of liver toxicity and toxic mechanism of traditional Chinese medicine. This paper provided ideas for the study of potential liver toxicity of traditional Chinese medicine and protection for clinical safety of traditional Chinese medicine. Copyright© by the Chinese Pharmaceutical Association.

A Predictive Velocity Observer in Wire Bonder’s Control System

Directory of Open Access Journals (Sweden)

Lei Zhou

2014-01-01

Full Text Available Wire bonder is a typical high speed machine. The motion speed of XY-stage is the key factor of bonding efficiency. However, phase lag elements in the servo system limit the bandwidth and slow down the system’s response. A predictive velocity observer is proposed to compensate for those phase lags. Then, the velocity loop controller can be designed as for a servo system which does not have those phase lags. Loop gains are enlarged and bandwidth is enlarged correspondingly. Then, the motion speed is improved and settling time is decreased. Experiment results verify that the predictive velocity observer provided a significant phase lead and the performance of wire bonder is improved.

SLOW SLIP EVENTS: PARAMETERS, CONDITIONS OF OCCURRENCE, AND FUTURE RESEARCH PROSPECTS

Directory of Open Access Journals (Sweden)

G. G. Kocharyan

2014-01-01

Full Text Available Slow slip events along faults and fractures are reviewed. Such inter-block displacements can be recorded at various scale levels and considered as transitional from quasi-stable (creep to dynamic slip (earthquake. Such events include seismogenic slip along faults at velocities by one to three orders lower than those in case of 'normal' earthquakes, as well as aseismic slip cases. Discovering such events facilitates better understanding of how energy accumulated during deformation of the crust is released.Studying conditions and the evolution of transitional regimes can provide new important information on the structure and regularities of deformation in fault zones.Data from latest publications by different authors are consolidated, and the data analysis results are presented. Over 170 slow slip events are reviewed. Based on the consolidated data and modelling results obtained by the authors, relationships between parameters of the reviewed process are established, scale relations between the events are considered, and a first-approximation analysis is conducted for impacts of geomaterial characteristics on various deformation regimes.Low-frequency earthquake foci and slow slip sites are most typically located in zones of transition from stable creep areas to seismogenic segments of the discontinuity (Fig. 3 It can be logically supposed that in such transitional zones, the interface has specific frictional properties providing for a regime that can be termed as 'conditionally stable slip'.The duration of slow deformation events is roughly proportional to the released seismic moment, while such a ratio is close to self-similarity in case of 'normal' earthquakes (Fig. 4. In case of slow slip, an area of the displaced section is larger by many factors than the corresponding value for an earthquake with the same seismic moment, while an average displacement amplitude along the fault is significantly smaller (Figures 5 and 6. Velocities of slip

"Fast" and "slow" skeleto-fusimotor innervation in cat tenuissimus spindles; a study with the glycogen-depletion method.

Science.gov (United States)

Jami, L; Lan-Couton, D; Malmgren, K; Petit, J

1978-07-01

The glycogen-depletion method was used to investigate the motor supply to tenuissimus with respect to the presence of fast beta axons and to assess the total proportion of both fast and slow beta-innervated spindles in this muscle. In a first series of 5 expts., groups of motor axons with conduction velocities higher than 85 m/s were repetitively stimulated so as to produce glycogen depletion in the muscle fibres they innervated. The whole muscle was then quick-frozen, serially cut, stained to demonstrate glycogen and examined for intrafusal glycogen depletion. Zones of glycogen depletion were found in 16 of the 46 examined spindles; they were most frequently located in the longest of the chain intrafusal muscle fibres. Since it is known that there are no purely fusimotor axons to tenuissimus with conduction velocities above 50 m/s, it was concluded that beta axons are present among the fastest axons to this muscle. In a second series of 5 expts. as many motor axons as possible with conduction velocities above 60 m/s were stimulated. Zones of glycogen depletion were found in 19 of the 47 examined spindles. They affected chain fibres in about half of the instances and bag1 fibers in the others. As this latter location is characteristic of slow dynamic beta axons, it was concluded that both slow and fast beta axons occur regularly in the motor supply to tenuissimus. beta-innervation is present in at least 40% of tenuissimus spindles with almost no convergence of fast and slow beta axons onto the same spindle.

Reliability of power and velocity variables collected during the traditional and ballistic bench press exercise.

Science.gov (United States)

García-Ramos, Amador; Haff, G Gregory; Padial, Paulino; Feriche, Belén

2018-03-01

This study aimed to examine the reliability of different power and velocity variables during the Smith machine bench press (BP) and bench press throw (BPT) exercises. Twenty-two healthy men conducted four testing sessions after a preliminary BP one-repetition maximum (1RM) test. In a counterbalanced order, participants performed two sessions of BP in one week and two sessions of BPT in another week. Mean propulsive power, peak power, mean propulsive velocity, and peak velocity at each tenth percentile (20-70% of 1RM) were recorded by a linear transducer. The within-participants coefficient of variation (CV) was higher for the load-power relationship compared to the load-velocity relationship in both the BP (5.3% vs. 4.1%; CV ratio = 1.29) and BPT (4.7% vs. 3.4%; CV ratio = 1.38). Mean propulsive variables showed lower reliability than peak variables in both the BP (5.4% vs. 4.0%, CV ratio = 1.35) and BPT (4.8% vs. 3.3%, CV ratio = 1.45). All variables were deemed reliable, with the peak velocity demonstrating the lowest within-participants CV. Based upon these findings, the peak velocity should be chosen for the accurate assessment of BP and BPT performance.

Seismic velocity anisotropy of phyllosilicate-rich rocks: characteristics inferred from experimental and crack-model studies of biotite-rich schist

Science.gov (United States)

Nishizawa, O.; Kanagawa, K.

2010-07-01

Seismic velocity anisotropy of biotite schist (30 per cent-mode biotite) was measured under confining pressures up to 150 MPa. The rock shows weak orthotropy which was altered from transverse isotropy (TI) generated by biotite-preferred orientation. The orthotropy was caused by microfolding in the rock. The velocity increase under confining pressure indicates that most crack planes are aligned parallel to the cleavage planes (silicate sheet) of the oriented biotite minerals. The anisotropy of the rock is basically TI due to both the aligned biotite minerals and cracks, which have a common symmetry axis. We found that other sheet silicate-rich rocks have a similar anisotropy with the biotite schist, in which the TI-type anisotropy is characterized by the slow P- and S-wave velocities along the symmetry axis. This is caused by the preferred orientation of sheet silicate minerals and the extremely slow P- and S-wave velocities along the axis perpendicular to the silicate sheet compared to the directions along the silicate sheet. When rock contains a large percentage of highly oriented sheet silicates, the fast and slow shear waves exchange their polarities at some off-symmetry axis directions, indicating that the qS-wave (quasi-S wave) velocity exceeds the SH-wave velocity. The phase velocity distribution of qS wave shows an asymmetry with respect to the angle from the symmetry axis, which is characterized by a bulge in this distribution located near the symmetric axis. This is inherent to most sheet silicate minerals. When crack density of aligned cracks increases, the P-wave velocity along the symmetry axis decreases considerably. The qS-wave phase velocity in the off-axis directions also decreases, in accordance with the decrease of the P velocity along the symmetry axis. The asymmetry of the qS-wave phase velocity distribution increases as the P-wave velocity decreases along the symmetry axis. This relationship can be well understood by means of Berryman

Experimental study on quantitative evaluation of slow pulsatile flow of CSF with cine MRI

International Nuclear Information System (INIS)

Matsuda, Masao

1991-01-01

The present study was designed to evaluate the slow pulsatile flow of cerebrospinal fluid (CSF) quantitatively with cine MRI in phantom experiment for the clinical application. The flow phantom was constructed from a plastic tube with a narrow channel to represent the central aqueduct. The phantom was filled with water to represent the CSF. The second tube filled with stationary water was positioned beside the flow phantom and acted as a control for no-flow signal strength. The ratio of signal intensity in regions of interest for the flow phantom and the control was measured. Not only the actual velocity curve of the flowing water through the phantom but also the temporal profile of signal intensity showed two main peaks with other small peaks in one cycle. This suggested a close relationship between signal intensity of cine MRI and flow velocity. A significant correlation between the signal intensity ratio and the velocity was obtained on cine MRI pulse sequences. Cine MRI was thus found to have the ability to give quantitative information about slow pulsatile flow. The most suitable pulse sequence was fast imaging with steady state free precession pulse sequence at the flip angle between 50 and 90 degrees. This preliminary study suggests that the slow pulsatile flow of CSF passing along the aqueduct can be visualized and measured. Thus, the sequence proposed has a potential for the investigation of normal and disturbed CSF circulation and the mapping of the flow pattern in different pathological conditions. (N.K.)

EISCAT measurements of solar wind velocity and the associated level of interplanetary scintillation

Directory of Open Access Journals (Sweden)

R. A. Fallows

2002-09-01

Full Text Available A relative scintillation index can be derived from EISCAT observations of Interplanetary Scintillation (IPS usually used to study the solar wind velocity. This provides an ideal opportunity to compare reliable measurements of the solar wind velocity derived for a number of points along the line-of-sight with measurements of the overall level of scintillation. By selecting those occasions where either slow- or fast-stream scattering was dominant, it is shown that at distances from the Sun greater than 30 RS , in both cases the scintillation index fell with increasing distance as a simple power law, typically as R-1.7. The level of scintillation for slow-stream scattering is found to be 2.3 times the level for fast-stream scattering.Key words. Interplanetary physics (solar wind plasma

Effect of hindlimb unweighting on single soleus fiber maximal shortening velocity and ATPase activity

Science.gov (United States)

Mcdonald, K. S.; Fitts, R. H.

1993-01-01

The effect of hindlimb unweighting (HU) for 1 to 3 wks on the shortening velocity of a soleus fiber, its ATPase content, and the relative contents of the slow and fast myosin was investigated by measuring fiber force, V(0), ATPase activity, and myosin content in SDS protein profiles of a single rat soleus fiber suspended between a motor arm and a transducer. It was found that HU induces a progressive increase in fiber V(0) that is likely caused, at least in part, by an increase in the fiber's myofibrillar ATPase activity. The HU-induced increases in V(0) and ATPase were associated with the presence of a greater percentage of fast type IIa fibers. However, a large population of fibers after 1, 2, and 3 wks of HU showed increases in V(0) and ATPase but displayed the same myosin protein profile on SDS gels as control fibers.

Interlimb communication following unexpected changes in treadmill velocity during human walking

DEFF Research Database (Denmark)

Stevenson, Andrew James Thomas; Geertsen, Svend Sparre; Sinkjær, Thomas

2015-01-01

Interlimb reflexes play an important role in human walking, particularly when dynamic stability is threatened by external perturbations or changes in the walking surface. Interlimb reflexes have recently been demonstrated in the contralateral biceps femoris (cBF) following knee joint rotations...... applied to the ipsilateral leg (iKnee) during the late stance phase of human gait (Stevenson et al. 2013). This interlimb reflex likely acts to slow the forward progression of the body in order to maintain dynamic stability following the perturbations. We examined this hypothesis by unexpectedly...... to slow the forward progression of the body and maintaining dynamic stability during walking, thus signifying a functional role for interlimb reflexes....

Slow Integral Manifolds and Control Problems in Critical and Twice Critical Cases

International Nuclear Information System (INIS)

Sobolev, Vladimir

2016-01-01

We consider singularly perturbed differential systems in cases where the standard theory to establish a slow integral manifold existence does not work. The theory has traditionally dealt only with perturbation problems near normally hyperbolic manifold of singularities and this manifold is supposed to isolated. Applying transformations we reduce the original singularly perturbed problem to a regularized one such that the existence of slow integral manifolds can be established by means of the standard theory. We illustrate our approach by several examples. (paper)

The effects of ramp stretches on active contractions in intact mammalian fast and slow muscle fibres.

Science.gov (United States)

Mutungi, G; Ranatunga, K W

2001-01-01

The effects of a ramp stretch (amplitude muscle fibre length (L0), speed twitch tension and twitch tension re-development were examined in intact mammalian (rat) fast and slow muscle fibre bundles. The experiments were done in vitro at 20 degrees C and at an initial sarcomere length of 2.68 microm. In both fibre types, a stretch applied during the rising phase of the twitch response (including the time of stimulation) increased the re-developed twitch tension (15-35%). A stretch applied before the stimulus had little or no effect on the twitch myogram in fast muscle fibres, but it increased the twitch tension (approximately 5%) in slow muscle fibres. A similar stretch had little or no effect on tetanic tension in either muscle fibre type. In general, the results indicate that the contractile-activation mechanism may be stretch sensitive and this is particularly pronounced in slow muscle fibres. Recorded at a high sampling rate and examined at an appropriate time scale, the transitory tension response to a stretch rose in at least two phases; an initial rapid tension rise to a break (break point tension, P1a) followed by a slower tension rise (apparent P2a) to a peak reached at the end of the stretch. Plotted against stretch velocity, P1a tension increased in direct proportion to stretch velocity (viscous-like) whereas, P2a tension (calculated as peak tension minus P1a tension) increased with stretch velocity to a plateau (visco-elastic). Examined at the peak of a twitch, P1a tension had a slope (viscosity coefficient) of 1.8 kN m(-2) per L0 s(-1) in fast fibres and 4.7 kN m(-2) per L0 s(-1) in slow muscle fibres. In the same preparations, P2a tension had a relaxation time of 8 ms in the fast muscle fibres and 25 ms in the slow muscle fibres. The amplitudes of both tension components scaled with the instantaneous twitch tension in qualitatively the same way as the instantaneous fibre stiffness. These fast/slow fibre type differences probably reflect differences in

More Falls in Cerebellar Ataxia When Standing on a Slow Up-Moving Tilt of the Support Surface.

Science.gov (United States)

Paquette, Caroline; Franzén, Erika; Horak, Fay B

2016-06-01

We investigated how subjects with cerebellar ataxia (CA) adapt their postural stability and alignment to a slow and small tilt of the support surface allowing for online postural corrections. Eight subjects with CA and eight age- and gender-matched healthy control subjects participated in the study. Subjects stood eyes closed for 1 min after which the support surface was tilted 5° toes-up at a ramp velocity of 1°/s. The toes-up position was held for 2.5 min after which the surface rotated back down to level with identical tilt characteristics. As reflected by the large number of falls, subjects with CA had marked difficulty adapting their posture to the up-moving incline in contrast to control subjects. Subjects with CA who lost their balance had faster trunk velocity and excessive backward trunk reorientation beginning within the first second after onset of the tilting surface. In contrast, the down-moving tilt to level did not result in instability in CA subjects. These results suggest that instability and falls associated with CA derive from an inability to maintain trunk orientation to vertical while standing on a slow-moving or unstable surface. This study underscores the importance of the cerebellum in the online sensory control of the upper body orientation during small amplitude and slow velocity movements of the support surface.

Strength evolution of simulated carbonate-bearing faults: The role of normal stress and slip velocity

Science.gov (United States)

Mercuri, Marco; Scuderi, Marco Maria; Tesei, Telemaco; Carminati, Eugenio; Collettini, Cristiano

2018-04-01

A great number of earthquakes occur within thick carbonate sequences in the shallow crust. At the same time, carbonate fault rocks exhumed from a depth plasticity). We performed friction experiments on water-saturated simulated carbonate-bearing faults for a wide range of normal stresses (from 5 to 120 MPa) and slip velocities (from 0.3 to 100 μm/s). At high normal stresses (σn > 20 MPa) fault gouges undergo strain-weakening, that is more pronounced at slow slip velocities, and causes a significant reduction of frictional strength, from μ = 0.7 to μ = 0.47. Microstructural analysis show that fault gouge weakening is driven by deformation accommodated by cataclasis and pressure-insensitive deformation processes (pressure solution and granular plasticity) that become more efficient at slow slip velocity. The reduction in frictional strength caused by strain weakening behaviour promoted by the activation of pressure-insensitive deformation might play a significant role in carbonate-bearing faults mechanics.

Reciprocal Influence of Slow Waves Extracted in Intracranial Pressure, Arterial Pressure and Cerebral Blood Velocity Signals

National Research Council Canada - National Science Library

Cervenansky, F

2001-01-01

...), and arterial blood pressure (ABP). To clarify the links, we compared two frequency methods based on coherence function to estimate the influence of ICP, ABP, and CBV on couples, respectively CBV-ABP, ICP-CBV and ICP-ABP, of slow waves...

Laser Cooling and Slowing of a Diatomic Molecule

Science.gov (United States)

2013-12-01

124]. For this example, we assume Mik = 0. The population fractions obey nj + Ng∑ i=1 ni = 1, (3.17) 11i.e. no π pulses, stimulated raman adiabatic...expensive for transitions requiring a CW dye laser (∼ $200k) or frequency doubled Raman fiber laser (∼ $120k) since generating light with the ∼ 15 GHz...lower than the mean thermal velocities of He, N2 or H20 at 293 K, which are ≈ 1250, 590 and 470 m/s respectively. Conceptually, the slow SrF molecules

On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

Energy Technology Data Exchange (ETDEWEB)

Verscharen, Daniel [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Chen, Christopher H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Wicks, Robert T., E-mail: daniel.verscharen@unh.edu, E-mail: christopher.chen@imperial.ac.uk, E-mail: r.wicks@ucl.ac.uk [Mullard Space Science Laboratory, University College London, London WC1E 6BT (United Kingdom)

2017-05-10

Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

International Nuclear Information System (INIS)

Verscharen, Daniel; Chen, Christopher H. K.; Wicks, Robert T.

2017-01-01

Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

Progression of motor symptoms in Parkinson's disease

Institute of Scientific and Technical Information of China (English)

Ruiping Xia; Zhi-Hong Mao

2012-01-01

Parkinson's disease (PD) is a chronic progressive neurodegenerative disease that is clinically manifested by a triad of cardinal motor symptoms - rigidity,bradykinesia and tremor - due to loss of dopaminergic neurons.The motor symptoms of PD become progressively worse as the disease advances.PD is also a heterogeneous disease since rigidity and bradykinesia are the major complaints in some patients whereas tremor is predominant in others.In recent years,many studies have investigated the progression of the hallmark symptoms over time,and the cardinal motor symptoms have different rates of progression,with the disease usually progressing faster in patients with rigidity and bradykinesia than in those with predominant tremor.The current treatment regime of dopamine-replacement therapy improves motor symptoms and alleviates disability.Increasing the dosage of dopaminergic medication is commonly used to combat the worsenirtg symptoms.However,the drug-induced involuntary body movements and motor comphcations can significantly contribute to overall disability.Further,none of the currently-available therapies can slow or halt the disease progression.Significant research efforts have been directed towards developing neuroprotective or disease-modifying agents that are intended to slow the progression.In this article,the most recent clinical studies investigating disease progression and current progress on the development of disease-modifying drug trials are reviewed.

Toward standardization of slow earthquake catalog -Development of database website-

Science.gov (United States)

Kano, M.; Aso, N.; Annoura, S.; Arai, R.; Ito, Y.; Kamaya, N.; Maury, J.; Nakamura, M.; Nishimura, T.; Obana, K.; Sugioka, H.; Takagi, R.; Takahashi, T.; Takeo, A.; Yamashita, Y.; Matsuzawa, T.; Ide, S.; Obara, K.

2017-12-01

Slow earthquakes have now been widely discovered in the world based on the recent development of geodetic and seismic observations. Many researchers detect a wide frequency range of slow earthquakes including low frequency tremors, low frequency earthquakes, very low frequency earthquakes and slow slip events by using various methods. Catalogs of the detected slow earthquakes are open to us in different formats by each referring paper or through a website (e.g., Wech 2010; Idehara et al. 2014). However, we need to download catalogs from different sources, to deal with unformatted catalogs and to understand the characteristics of different catalogs, which may be somewhat complex especially for those who are not familiar with slow earthquakes. In order to standardize slow earthquake catalogs and to make such a complicated work easier, Scientific Research on Innovative Areas "Science of Slow Earthquakes" has been developing a slow earthquake catalog website. In the website, we can plot locations of various slow earthquakes via the Google Maps by compiling a variety of slow earthquake catalogs including slow slip events. This enables us to clearly visualize spatial relations among slow earthquakes at a glance and to compare the regional activities of slow earthquakes or the locations of different catalogs. In addition, we can download catalogs in the unified format and refer the information on each catalog on the single website. Such standardization will make it more convenient for users to utilize the previous achievements and to promote research on slow earthquakes, which eventually leads to collaborations with researchers in various fields and further understanding of the mechanisms, environmental conditions, and underlying physics of slow earthquakes. Furthermore, we expect that the website has a leading role in the international standardization of slow earthquake catalogs. We report the overview of the website and the progress of construction. Acknowledgment: This

Slow, target associated particles produced in ultrarelativistic heavy-ion interactions

Energy Technology Data Exchange (ETDEWEB)

Adamovich, M I; Aggarwal, M M; Alexandrov, Y A; Andreeva, N P; Anson, Z V; Arora, R; Avetyan, F A; Badyal, S K; Basova, E; Bhalla, K B; Bhasin, A; Bhatia, V S; Bogdanov, V G; Bubnov, V I; Burnett, T H; Cai, X; Chasnikov, I Y; Chernova, L P; Chernyavsky, M M; Dressel, B; Eligbaeva, G Z; Eremenko, L E; Friedlander, E M; Gaitinov, A S; Ganssauge, E R; Garpman, S; Gerassimov, S G; Grote, J; Gulamov, K G; Gupta, S K; Gupta, V; Heckman, H H; Huang, H; Jakobsson, B; Judek, B; Kachroo, S; Kadyrov, F G; Kalyachkina, G S; Kanygina, E K; Karabova, M; Kaul, G L; Kaur, M; Kharlamov, S P; Koss, Y; Krasnov,; Kumar,; Lal, P; Larionova,; Lepetan,; Lindstrom,; Liu,; Lokanathan, S; Lord, J; Lukicheva, N S; Luo, S B; Mangotra, L K; Marutyan,; Maslennikova, N V; Mittra, I S; Mookerjee, S; Mueller, C; Nasrulaeva, H; Nasyrov, S H; Navotny, V S; Orlova, G I; Otterlund, I; Palsania, H S; Peresadko, N G; Petrov, N V; Plyushchev, V A; Qian, W Y; Raniwala,; EMU01 Collaboration

1991-06-20

The slow, target associated particles produced in ultrarelativistic heavy-ion interactions are a quantitative probe of the cascading processes in the spectator parts of the target nucleus. These processes are directly influenced by the proper timescale for the formation of hadronic matter. In this letter we show experimental data on singly and multiply charged particles, with velocities smaller than 0.7c, produced in ultrarelativistic heavy-ion interactions in nuclear emulsion. (orig.).

Influence of perturbation velocity on balance control in Parkinson's disease.

Directory of Open Access Journals (Sweden)

Lars B Oude Nijhuis

Full Text Available Underlying somatosensory processing deficits of joint rotation velocities may cause patients with Parkinson's disease (PD to be more unstable for fast rather than slow balance perturbations. Such deficits could lead to reduced proprioceptive amplitude feedback triggered by perturbations, and thereby to smaller or delayed stabilizing postural responses. For this reason, we investigated whether support surface perturbation velocity affects balance reactions in PD patients. We examined postural responses of seven PD patients (OFF medication and eight age-matched controls following backward rotations of a support-surface platform. Rotations occurred at three different speeds: fast (60 deg/s, medium (30 deg/s or slow (3.8 deg/s, presented in random order. Each subject completed the protocol under eyes open and closed conditions. Full body kinematics, ankle torques and the number of near-falls were recorded. Patients were significantly more unstable than controls following fast perturbations (26% larger displacements of the body's centre of mass; P<0.01, but not following slow perturbations. Also, more near-falls occurred in patients for fast rotations. Balance correcting ankle torques were weaker for patients than controls on the most affected side, but were stronger than controls for the least affected side. These differences were present both with eyes open and eyes closed (P<0.01. Fast support surface rotations caused greater instability and discriminated Parkinson patients better from controls than slow rotations. Although ankle torques on the most affected side were weaker, patients partially compensated for this by generating larger than normal stabilizing torques about the ankle joint on the least affected side. Without this compensation, instability may have been greater.

Low, slow, small target recognition based on spatial vision network

Science.gov (United States)

Cheng, Zhao; Guo, Pei; Qi, Xin

2018-03-01

Traditional photoelectric monitoring is monitored using a large number of identical cameras. In order to ensure the full coverage of the monitoring area, this monitoring method uses more cameras, which leads to more monitoring and repetition areas, and higher costs, resulting in more waste. In order to reduce the monitoring cost and solve the difficult problem of finding, identifying and tracking a low altitude, slow speed and small target, this paper presents spatial vision network for low-slow-small targets recognition. Based on camera imaging principle and monitoring model, spatial vision network is modeled and optimized. Simulation experiment results demonstrate that the proposed method has good performance.

Slow progression of paediatric HIV disease: Selective adaptation or ...

African Journals Online (AJOL)

In the European Caucasian populations, the chemokine-cell receptor variant CCR5 \\"Delta 32\\" is a the genetic determinant of HIV disease progression that is believed to have been selected for in the general population by exposure to antigens closely interlinked to HIV like Yersinia pestis or small pox virus. Among African ...

Indomethacin Treatment of Mice with Premalignant Oral Lesions Sustains Cytokine Production and Slows Progression to Cancer.

Science.gov (United States)

Johnson, Sara D; Young, M Rita I

2016-01-01

Current treatment options for head and neck squamous cell carcinoma (HNSCC) patients are often ineffective due to tumor-localized and systemic immunosuppression. Using the 4-NQO mouse model of oral carcinogenesis, this study showed that premalignant oral lesion cells produce higher levels of the immune modulator, PGE 2 , compared to HNSCC cells. Inhibiting prostaglandin production of premalignant lesion cells with the pan-cyclooxygenase inhibitor indomethacin stimulated their induction of spleen cell cytokine production. In contrast, inhibiting HNSCC prostaglandin production did not stimulate their induction of spleen cell cytokine production. Treatment of mice bearing premalignant oral lesions with indomethacin slowed progression of premalignant oral lesions to HNSCC. Flow cytometric analysis of T cells in the regional lymph nodes of lesion-bearing mice receiving indomethacin treatment showed an increase in lymph node cellularity and in the absolute number of CD8 + T cells expressing IFN-γ compared to levels in lesion-bearing mice receiving diluent control treatment. The cytokine-stimulatory effect of indomethacin treatment was not localized to regional lymph nodes but was also seen in the spleen of mice with premalignant oral lesions. Together, these data suggest that inhibiting prostaglandin production at the premalignant lesion stage boosts immune capability and improves clinical outcomes.

Beta-Zone parapapillary atrophy and the velocity of glaucoma progression.

Science.gov (United States)

Teng, Christopher C; De Moraes, Carlos Gustavo V; Prata, Tiago S; Tello, Celso; Ritch, Robert; Liebmann, Jeffrey M

2010-05-01

Beta-Zone parapapillary atrophy (PPA) occurs more commonly in eyes with glaucoma. Rates of glaucomatous visual field (VF) progression in eyes with and without beta-zone PPA at the time of baseline assessment were compared. Retrospective, comparative study. Two hundred forty-five patients from the New York Glaucoma Progression Study. Subjects with glaucomatous optic neuropathy and repeatable VF loss were assessed for eligibility. Eyes with a Heidelberg Retina Tomograph II (HRT) examination, at least 5 visual field tests after the HRT in either eye, optic disc photographs, and Zone PPA was defined as a region of chorioretinal atrophy with visible sclera and choroidal vessels adjacent to the optic disc. Global rates of VF progression were determined by automated pointwise linear regression analysis. Univariate analysis included age, gender, ethnicity, central corneal thickness (CCT), refractive error, baseline mean deviation, baseline intraocular pressure (IOP), mean IOP, IOP fluctuation, disc area, rim area, rim area-to-disc area ratio, beta-zone PPA area, beta-zone PPA area-to-disc area ratio, and presence or absence of beta-zone PPA. The relationship between beta-zone PPA and the rate and risk of glaucoma progression. Two hundred forty-five eyes of 245 patients (mean age, 69.6+/-12.3 years) were enrolled. The mean follow-up was 4.9+/-1.4 years and the mean number of VFs after HRT was 9.3+/-2.7. beta-Zone PPA was present in 146 eyes (65%). Eyes with beta-zone PPA progressed more rapidly (-0.84+/-0.8 dB/year) than eyes without it (-0.51+/-0.6 dB/year; Pzone PPA (HR, 2.59; P1.5 dB/year; P = 0.08) global rates of progression occurred more commonly in eyes with beta-zone PPA than in eyes without it. Thinner CCT (zone PPA (kappa = 0.13). Eyes with beta-zone PPA are at increased risk for glaucoma progression and warrant close clinical surveillance. Copyright 2010 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Generation of microwaves by a slow wave electron cyclotron maser with axial injection

International Nuclear Information System (INIS)

Michie, R.B.; Vomvoridis, J.

1984-01-01

Experimental measurements of microwave generation by a new electron beam wave interaction is presented. This slow wave electron cyclotron maser (ECM) has a continuous electron beam injected axially into a slow wave structure containing a circularly polarized HE, hybrid electric (HE) mode. A longitudinal magnetic field produces microwaves by maser action. The slow wave structure allows energy to be coupled out of an electron beam with no initial transverse momentum. This is similar to klystrons, traveling wave tubes, and Cherenkov masers, but there is no axial beam bunching. Therefore, ECM designs using relativistic electron beams are allowed. This ECM is similar to a gyrotron in that the electrons are coupled through their cyclotron motion to the wave, but there is no need for initial electron velocity perpendicular to the background magnetic field. Therefore, a narrower spread of electron beam energy about the ECM resonance is possible which gives higher theoretical efficiency. A nonlinear analysis of energy coupling of electrons to the slow wave in the ECM and the design of the slow wave ECM microwave amplifier at 10 GHz using a 200 KeV axial electron beam in 3 KG magnetic field is included

A viscoplastic shear-zone model for deep (15-50 km) slow-slip events at plate convergent margins

Science.gov (United States)

Yin, An; Xie, Zhoumin; Meng, Lingsen

2018-06-01

A key issue in understanding the physics of deep (15-50 km) slow-slip events (D-SSE) at plate convergent margins is how their initially unstable motion becomes stabilized. Here we address this issue by quantifying a rate-strengthening mechanism using a viscoplastic shear-zone model inspired by recent advances in field observations and laboratory experiments. The well-established segmentation of slip modes in the downdip direction of a subduction shear zone allows discretization of an interseismic forearc system into the (1) frontal segment bounded by an interseismically locked megathrust, (2) middle segment bounded by episodically locked and unlocked viscoplastic shear zone, and (3) interior segment that slips freely. The three segments are assumed to be linked laterally by two springs that tighten with time, and the increasing elastic stress due to spring tightening eventually leads to plastic failure and initial viscous shear. This simplification leads to seven key model parameters that dictate a wide range of mechanical behaviors of an idealized convergent margin. Specifically, the viscoplastic rheology requires the initially unstable sliding to be terminated nearly instantaneously at a characteristic velocity, which is followed by stable sliding (i.e., slow-slip). The characteristic velocity, which is on the order of <10-7 m/s for the convergent margins examined in this study, depends on the (1) effective coefficient of friction, (2) thickness, (3) depth, and (4) viscosity of the viscoplastic shear zone. As viscosity decreases exponentially with temperature, our model predicts faster slow-slip rates, shorter slow-slip durations, more frequent slow-slip occurrences, and larger slow-slip magnitudes at warmer convergent margins.

Is there a relation between EEG-slow waves and memory dysfunction in epilepsy? A critical appraisal.

Directory of Open Access Journals (Sweden)

Höller eYvonne

2015-06-01

Full Text Available Is there a relationship between peri-ictal slow waves, loss of consciousness, memory, and slow wave sleep, in patients with different forms of epilepsy? We hypothesize that mechanisms which result in peri-ictal slow wave activity as detected by the electroencephalogram could negatively affect memory processes.Slow waves (≤ 4 Hz can be found in seizures with impairment of consciousness and also occur in focal seizures without impairment of consciousness but with inhibited access to memory functions. Peri-ictal slow waves are regarded as dysfunctional and are probably caused by mechanisms which are essential to disturb the consolidation of memory entries in these patients. This is in strong contrast to physiological slow wave activity during deep sleep, which is thought to group memory-consolidating fast oscillatory activity.In patients with epilepsy, slow waves may not only correlate with the peri-ictal clouding of consciousness, but could be the epiphenomenon of mechanisms which interfere with normal brain function in a wider range. These mechanisms may have transient impacts on memory, such as temporary inhibition of memory systems, altered patterns of hippocampal-neocortical interactions during slow wave sleep, or disturbed cross-frequency coupling of slow and fast oscillations. In addition, repeated tonic-clonic seizures over the years in uncontrolled chronic epilepsy may cause a progressive cognitive decline.This hypothesis can only be assessed in long term prospective studies. These studies could disentangle the reversible short-term impacts of seizures, and the impacts of chronic uncontrolled seizures. Chronic uncontrolled seizures lead to irreversible memory impairment. In contrast, short term impacts do not necessarily lead to a progressive cognitive decline but result in significantly impaired peri-ictal memory performance.

Acute effects of movement velocity on blood lactate and growth hormone responses after eccentric bench press exercise in resistance-trained men.

Science.gov (United States)

Calixto, Rd; Verlengia, R; Crisp, Ah; Carvalho, Tb; Crepaldi, Md; Pereira, Aa; Yamada, Ak; da Mota, Gr; Lopes, Cr

2014-12-01

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric (1RMecc) test, with 2-minute rest intervals between sets. The eccentric velocity was controlled to 3 seconds per range of motion for SEV and 0.5 seconds for the FEV group. There was a significant difference (P bench press exercise in the SEV group (1.7 ± 0.6 ng · mL(-1)) relative to the FEV group (0.1 ± 0.0 ng · mL(-1)). In conclusion, the velocity of eccentric muscle action influences acute responses following bench press exercises performed by resistance-trained men using a slow velocity resulting in a greater metabolic stress and hormone response.

Sparking Thinking: Studying Modern Precision Medicine Will Accelerate the Progression of Traditional Chinese Medicine Patterns.

Science.gov (United States)

Liu, Bao-Cheng; Ji, Guang

2017-07-01

Incorporating "-omics" studies with environmental interactions could help elucidate the biological mechanisms responsible for Traditional Chinese Medicine (TCM) patterns. Based on the authors' own experiences, this review outlines a model of an ideal combination of "-omics" biomarkers, environmental factors, and TCM pattern classifications; provides a narrative review of the relevant genetic and TCM studies; and lists several successful integrative examples. Two integration tools are briefly introduced. The first is the integration of modern devices into objective diagnostic methods of TCM patterning, which would improve current clinical decision-making and practice. The second is the use of biobanks and data platforms, which could broadly support biological and medical research. Such efforts will transform current medical management and accelerate the progression of precision medicine.

Ultrahigh enhancement in absolute and relative rotation sensing using fast and slow light

International Nuclear Information System (INIS)

Shahriar, M. S.; Pati, G. S.; Tripathi, R.; Gopal, V.; Messall, M.; Salit, K.

2007-01-01

We describe a resonator-based optical gyroscope whose sensitivity for measuring absolute rotation is enhanced via use of the anomalous dispersion characteristic of superluminal light propagation. The enhancement is given by the inverse of the group index, saturating to a bound determined by the group velocity dispersion. We also show how the offsetting effect of the concomitant broadening of the resonator linewidth may be circumvented by using an active cavity. For realistic conditions, the enhancement factor is as high as 10 6 . We also show how normal dispersion used for slow light can enhance relative rotation sensing in a specially designed Sagnac interferometer, with the enhancement given by the slowing factor

Electron velocity distributions near collisionless shocks

International Nuclear Information System (INIS)

Feldman, W.C.

1984-01-01

Recent studies of the amount of electron heating and of the shapes of electron velocity distributions across shocks near the earth are reviewed. It is found that electron heating increases with increasing shock strength but is always less than the ion heating. The scale length of electron heating is also less than that for the ions. Electron velocity distributions show characteristic shapes which depend on the strength of the shocks. At the weaker shocks, electron heating is mostly perpendicular to the ambient magnetic field, bar B, and results in Gaussian-shaped velocity distributions at low-to-moderate energies. At the stronger shocks, parallel heating predominates resulting in flat-topped velocity distributions. A reasonable interpretation of these results indicates that at the weaker shocks electron heating is dominated by a tendency toward conservation of the magnetic moment. At the stronger fast-mode shocks, this heating is thought to be dominated by an acceleration parallel to bar B produced by the macroscopic shock electric field followed by beam driven plasma instabilities. Some contribution to the heating at the stronger shocks from conservation of the magnetic moment and cross-field current-driven instabilities cannot be ruled out. Although the heating at slow-mode shocks is also dominated by instabilities driven by magnetic field-aligned electron beams, their acceleration mechanism is not yet established

Tremor-genic slow slip regions may be deeper and warmer and may slip slower than non-tremor-genic regions

Science.gov (United States)

Montgomery-Brown, Emily; Syracuse, Ellen M.

2015-01-01

Slow slip events (SSEs) are observed worldwide and often coincide with tectonic tremor. Notable examples of SSEs lacking observed tectonic tremor, however, occur beneath Kīlauea Volcano, Hawaii, the Boso Peninsula, Japan, near San Juan Bautista on the San Andreas Fault, California, and recently in Central Ecuador. These SSEs are similar to other worldwide SSEs in many ways (e.g., size or duration), but lack the concurrent tectonic tremor observed elsewhere; instead, they trigger swarms of regular earthquakes. We investigate the physical conditions that may distinguish these non-tremor-genic SSEs from those associated with tectonic tremor, including slip velocity, pressure, temperature, fluids, and fault asperities, although we cannot eliminate the possibility that tectonic tremor may be obscured in highly attenuating regions. Slip velocities of SSEs at Kīlauea Volcano (∼10−6 m/s) and Boso Peninsula (∼10−7 m/s) are among the fastest SSEs worldwide. Kīlauea Volcano, the Boso Peninsula, and Central Ecuador are also among the shallowest SSEs worldwide, and thus have lower confining pressures and cooler temperatures in their respective slow slip zones. Fluids also likely contribute to tremor generation, and no corresponding zone of high vp/vs has been noted at Kīlauea or Boso. We suggest that the relatively faster slip velocities at Kīlauea Volcano and the Boso Peninsula result from specific physical conditions that may also be responsible for triggering swarms of regular earthquakes adjacent to the slow slip, while different conditions produce slower SSE velocities elsewhere and trigger tectonic tremor.

Seismic velocity structure and microearthquake source properties at The Geysers, California, geothermal area

Energy Technology Data Exchange (ETDEWEB)

O' Connell, D.R.

1986-12-01

The method of progressive hypocenter-velocity inversion has been extended to incorporate S-wave arrival time data and to estimate S-wave velocities in addition to P-wave velocities. S-wave data to progressive inversion does not completely eliminate hypocenter-velocity tradeoffs, but they are substantially reduced. Results of a P and S-wave progressive hypocenter-velocity inversion at The Geysers show that the top of the steam reservoir is clearly defined by a large decrease of V/sub p//V/sub s/ at the condensation zone-production zone contact. The depth interval of maximum steam production coincides with minimum observed V/sub p//V/sub s/, and V/sub p//V/sub s/ increses below the shallow primary production zone suggesting that reservoir rock becomes more fluid saturated. The moment tensor inversion method was applied to three microearthquakes at The Geysers. Estimated principal stress orientations were comparable to those estimated using P-wave firstmotions as constraints. Well constrained principal stress orientations were obtained for one event for which the 17 P-first motions could not distinguish between normal-slip and strike-slip mechanisms. The moment tensor estimates of principal stress orientations were obtained using far fewer stations than required for first-motion focal mechanism solutions. The three focal mechanisms obtained here support the hypothesis that focal mechanisms are a function of depth at The Geysers. Progressive inversion as developed here and the moment tensor inversion method provide a complete approach for determining earthquake locations, P and S-wave velocity structure, and earthquake source mechanisms.

Three-Dimensional Slowness Images of the Upper Crust Beneath the Lucky Strike Hydrothermal Vent Sites

Science.gov (United States)

Seher, T.; Crawford, W.; Singh, S.; Canales, J. P.; Combier, V.; Cannat, M.; Carton, H.; Dusunur, D.; Escartin, J.; Miranda, M. J.; Pouillet-Erguy, A.

2005-12-01

In June-July 2005 we carried out the SISMOMAR cruise, as part of the MOMAR project (Monitoring the Mid-Atlantic Ridge). Within this cruise, we conducted a 3D seismic reflection survey over an 18 km km x 3.8 km area covering both the Lucky Strike volcano and hydrothermal vents field. In order to have a full coverage inside the 3D box, shots continued for 2.25 km on either side of the box and extended out to the median valley bounding faults. To complement the streamer measurements 25 Ocean Bottom Seismometers (OBS) were placed in an 18 km x 18 km area. 11 OBS positions lie inside the 3D box and can be used to determine a very detailed image of the 3D velocity structure beneath the Lucky Strike volcano and hydrothermal vents field. For the 3D box a tuned array of 14 air guns (2600 cubic inches) was fired at an interval of 37.5 m for a total of 39 lines. We will present the first results of the OBS measurements near the Lucky Strike volcano. As a first step towards a joint 3D travel time and slowness (the inverse of velocity at turning depth) tomography, we present the 3D slowness function (latitude, longitude, offset), which can be considered as a 3D brute stack velocity image of the sub-surface (c.f. Barton and Edwards, 1999). The presence of fluid in the upper crust due to hydrothermal circulation should appear as a low velocity anomaly beneath the hydrothermal vents. In the next step the OBS measurements will be used to corroborate the reflection images of layer 2A observed in the streamer data for the 3D box. The OBS inside the 3D box recorded turning ray arrivals from the upper crust at a very fine sampling interval (37.5 m x 100 m) over a large azimuth. This provides the unique opportunity for jointly inverting travel time and slowness. Hence the measurements contain information on local gradients and should provide a very detailed velocity model of the subsurface, including information on hydrothermal systems and a possilbe anisotropy (e.g. Cherret and Singh

Kinematic Mechanisms of How Power Training Improves Healthy Old Adults' Gait Velocity

NARCIS (Netherlands)

Beijersbergen, Chantal M. I.; Granacher, Urs; Gäbler, Martijn; Devita, Paul; Hortobagyi, Tibor

Introduction: Slow gait predicts many adverse clinical outcomes in old adults, but the mechanisms of how power training can minimize the age-related loss of gait velocity is unclear. We examined the effects of 10 wk of lower extremity power training and detraining on healthy old adults' lower

Surface Wave Velocity-Stress Relationship in Uniaxially Loaded Concrete

DEFF Research Database (Denmark)

Shokouhi, Parisa; Zoëga, Andreas; Wiggenhauser, Herbert

2012-01-01

The sonic surface wave (or Rayleigh wave) velocity measured on prismatic concrete specimens under uniaxial compression was found to be highly stress-dependent. At low stress levels, the acoustoelastic effect and the closure of existing microcracks results in a gradual increase in surface wave...... velocities. At higher stress levels, concrete suffers irrecoverable damage: the existing microcracks widen and coalesce and new microcracks form. This progressive damage process leads first to the flattening and eventually the drop in the velocity-stress curves. Measurements on specimens undergoing several...... loading cycles revealed that the velocities show a stress-memory effect in good agreement with the Kaiser effect. Comparing the velocities measured during loading and unloading, the effects of stress and damage on the measured velocities could be differentiated. Moreover, the stress dependency of surface...

Slow component of VO2 kinetics: Mechanistic bases and practical applications

DEFF Research Database (Denmark)

Jones, Andrew M; Grassi, Bruno; Christensen, Peter Møller

2011-01-01

with the progressive recruitment of additional (type II) muscle fibers that are presumed to have lower efficiency. Recent studies, however, indicate that muscle efficiency is also lowered (resulting in a 'mirror-image'V¿O2 slow component) during fatiguing, high-intensity exercise in which additional fiber recruitment...

Progressive Red Shifts in the Late-Time Spectra of Type Ia Supernovae

Science.gov (United States)

Black, Christine; Fesen, Robert; Parrent, Jerod

2017-01-01

We examine the evolution of late-time, optical nebular features of Type Ia supernovae (SNe Ia) using a sample consisting of 160 spectra of 27 normal SNe Ia taken from the literature as well as unpublished spectra of SN 2008Q and ASASSN-14lp. Particular attention is given to nebular features between 4000-6000 Ang in terms of temporal changes in width and central wavelength. Analysis of the prominent late-time 4700 Ang feature shows a progressive central wavelength shift from ˜4600 Ang to longer wavelengths out to at least day +300 for our entire sample. We find no evidence for the feature’s red-ward shift slowing or halting at an [Fe III] blend centroid ˜4700 Ang as has been proposed. Two weaker adjacent features at around 4850 and 5000 Ang exhibit similar red shifts to that of the 4700 Ang feature. We conclude that the ubiquitous red shift of these common late-time SN Ia spectral features is not mainly due to a decrease in line velocities of forbidden Fe emissions, but the result of decreasing line velocities and opacity of permitted Fe absorption lines.

Different Effects of Sleep Deprivation and Torpor on EEG Slow-Wave Characteristics in Djungarian Hamsters.

Science.gov (United States)

Vyazovskiy, V V; Palchykova, S; Achermann, P; Tobler, I; Deboer, T

2017-02-01

It has been shown previously in Djungarian hamsters that the initial electroencephalography (EEG) slow-wave activity (power in the 0.5-4.0 Hz band; SWA) in non-rapid eye movement (NREM) sleep following an episode of daily torpor is consistently enhanced, similar to the SWA increase after sleep deprivation (SD). However, it is unknown whether the network mechanisms underlying the SWA increase after torpor and SD are similar. EEG slow waves recorded in the neocortex during sleep reflect synchronized transitions between periods of activity and silence among large neuronal populations. We therefore set out to investigate characteristics of individual cortical EEG slow waves recorded during NREM sleep after 4 h SD and during sleep after emergence from an episode of daily torpor in adult male Djungarian hamsters. We found that during the first hour after both SD and torpor, the SWA increase was associated with an increase in slow-wave incidence and amplitude. However, the slopes of single slow waves during NREM sleep were steeper in the first hour after SD but not after torpor, and, in contrast to sleep after SD, the magnitude of change in slopes after torpor was unrelated to the changes in SWA. Furthermore, slow-wave slopes decreased progressively within the first 2 h after SD, while a progressive increase in slow-wave slopes was apparent during the first 2 h after torpor. The data suggest that prolonged waking and torpor have different effects on cortical network activity underlying slow-wave characteristics, while resulting in a similar homeostatic sleep response of SWA. We suggest that sleep plays an important role in network homeostasis after both waking and torpor, consistent with a recovery function for both states. © The Author 2017. Published by Oxford University Press.

Causes and implications of the slow pace of technology transfer and ...

African Journals Online (AJOL)

The major problem facing most developing countries today is the need to transform their agricultural industries from one depending on traditional inputs with low productivity to one based on modern input with higher productivity. The study was set up to examine the causes and implication of slow pace of technology transfer ...

On the possibility of the autoresonant motion of an electron in a slow electromagnetic wave

International Nuclear Information System (INIS)

Milantiev, V.P.

1994-01-01

By autoresonant motion one usually means the motion when the condition of cyclotron resonance of gyrating particle with electromagnetic wave is conserved during all the time of the motion in spite of the relativistic mass increase. Such a motion takes place only in the case of vacuum wave, when the phase velocity ν p is equal to the speed of light in a vacuum C. Otherwise autoresonance is impossible, and energy of the particle oscillates in time. The authors now discuss the possibility of the autoresonance in a slow electromagnetic wave (ν p < c) propagating along the straight lines of the external magnetic field. It turns out that the autoresonant regime of the motion in a slow electromagnetic wave possible if some rather restrictive relations between the electric drift velocity and the phase velocity of wave take place. It depends also on the polarization of wave. The general case of the elliptical polarization is considered. The optimal regime corresponds to the wave with linear polarization in the direction of the constant electric field. For this case the calculations show that energy of the particle can unlimitedly increase (or decrease). The rate of acceleration can be even larger than in the case of vacuum wave. Radiation forces will restrict this process

Slow creep in soft granular packings.

Science.gov (United States)

Srivastava, Ishan; Fisher, Timothy S

2017-05-14

Transient creep mechanisms in soft granular packings are studied numerically using a constant pressure and constant stress simulation method. Rapid compression followed by slow dilation is predicted on the basis of a logarithmic creep phenomenon. Characteristic scales of creep strain and time exhibit a power-law dependence on jamming pressure, and they diverge at the jamming point. Microscopic analysis indicates the existence of a correlation between rheology and nonaffine fluctuations. Localized regions of large strain appear during creep and grow in magnitude and size at short times. At long times, the spatial structure of highly correlated local deformation becomes time-invariant. Finally, a microscale connection between local rheology and local fluctuations is demonstrated in the form of a linear scaling between granular fluidity and nonaffine velocity.

Slow Movement/Slow University: Critical Engagements. Introduction to the Thematic Section

Directory of Open Access Journals (Sweden)

Maggie O'Neill

2014-09-01

Full Text Available This thematic section emerged from two seminars that took place at Durham University in England in November 2013 and March 2014 on the possibilities for thinking through what a change movement towards slow might mean for the University. Slow movements have emerged in relation to a number of topics: Slow food, Citta slow and more recently, slow science. What motivated us in the seminars was to explore how far these movements could help us address the acceleration and intensification of work within our own and other universities, and indeed, what new learning, research, philosophies, practices, structures and governance might emerge. This editorial introduction presents the concept of the "slow university" and introduces our critical engagements with slow. The articles presented here interrogate the potentialities, challenges, problems and pitfalls of the slow university in an era of corporate culture and management rationality. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1403166

Spectral Velocity Estimation in the Transverse Direction

DEFF Research Database (Denmark)

Jensen, Jørgen Arendt

2013-01-01

A method for estimating the velocity spectrum for a fully transverse flow at a beam-to-flow angle of 90is described. The approach is based on the transverse oscillation (TO) method, where an oscillation across the ultrasound beam is made during receive processing. A fourth-order estimator based...... on the correlation of the received signal is derived. A Fourier transform of the correlation signal yields the velocity spectrum. Performing the estimation for short data segments gives the velocity spectrum as a function of time as for ordinary spectrograms, and it also works for a beam-to-flow angle of 90...... estimation scheme can reliably find the spectrum at 90, where a traditional estimator yields zero velocity. Measurements have been conducted with the SARUS experimental scanner and a BK 8820e convex array transducer (BK Medical, Herlev, Denmark). A CompuFlow 1000 (Shelley Automation, Inc, Toronto, Canada...

Multiple scattering of slow muons in an electron gas

International Nuclear Information System (INIS)

Archubi, C.D.; Arista, N.R.

2017-01-01

A comparative study of the angular dispersion of slow muons in an electron gas is performed using 3 dielectric models which represent the case of metals (Lindhard model for a free electron gas) and the cases of semiconductors and insulators (Levine and Louie model and Brandt and Reinheimer model for systems with a band gap) and a non-linear model for both cases at very low velocities. The contribution of collective electronic excitations according to the dielectric model are found to be negligible. The results from the calculation using Lindhard expressions for the angular half width are consistent with the result of a multiple scattering model. In particular, the effects produced by the band gap of the material are analyzed in detail. Finally, as the recoil effect is negligible, there is an almost exact scaling, for a given velocity, between the proton and the muon results. (authors)

Stochastic inflation in phase space: is slow roll a stochastic attractor?

Energy Technology Data Exchange (ETDEWEB)

Grain, Julien [Institut d' Astrophysique Spatiale, UMR8617, CNRS, Univ. Paris Sud, Université Paris-Saclay, Bt. 121, Orsay, F-91405 (France); Vennin, Vincent, E-mail: julien.grain@ias.u-psud.fr, E-mail: vincent.vennin@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO13FX (United Kingdom)

2017-05-01

An appealing feature of inflationary cosmology is the presence of a phase-space attractor, ''slow roll'', which washes out the dependence on initial field velocities. We investigate the robustness of this property under backreaction from quantum fluctuations using the stochastic inflation formalism in the phase-space approach. A Hamiltonian formulation of stochastic inflation is presented, where it is shown that the coarse-graining procedure—where wavelengths smaller than the Hubble radius are integrated out—preserves the canonical structure of free fields. This means that different sets of canonical variables give rise to the same probability distribution which clarifies the literature with respect to this issue. The role played by the quantum-to-classical transition is also analysed and is shown to constrain the coarse-graining scale. In the case of free fields, we find that quantum diffusion is aligned in phase space with the slow-roll direction. This implies that the classical slow-roll attractor is immune to stochastic effects and thus generalises to a stochastic attractor regardless of initial conditions, with a relaxation time at least as short as in the classical system. For non-test fields or for test fields with non-linear self interactions however, quantum diffusion and the classical slow-roll flow are misaligned. We derive a condition on the coarse-graining scale so that observational corrections from this misalignment are negligible at leading order in slow roll.

Simultaneous realization of slow and fast acoustic waves using a fractal structure of Koch curve.

Science.gov (United States)

Ding, Jin; Fan, Li; Zhang, Shu-Yi; Zhang, Hui; Yu, Wei-Wei

2018-01-24

An acoustic metamaterial based on a fractal structure, the Koch curve, is designed to simultaneously realize slow and fast acoustic waves. Owing to the multiple transmitting paths in the structure resembling the Koch curve, the acoustic waves travelling along different paths interfere with each other. Therefore, slow waves are created on the basis of the resonance of a Koch-curve-shaped loop, and meanwhile, fast waves even with negative group velocities are obtained due to the destructive interference of two acoustic waves with opposite phases. Thus, the transmission of acoustic wave can be freely manipulated with the Koch-curve shaped structure.

Slow rate of progression of grade 1 and 2+ aortic regurgitation.

Science.gov (United States)

Patel, Reena; Kamath, Ashvin; Varadarajan, Padmini; Krishnan, Srikanth; Pai, Ramdas G

2012-05-01

Although the progression of aortic stenosis has been well studied, the rate of progression of aortic regurgitation (AR) has not been definitively established. Further data would be valuable for clinical decision-making in patients with milder degrees of AR undergoing non-aortic valve cardiac surgery. Hence, this point was investigated in a large cohort of patients with grade 1 or 2+ AR. The authors' echocardiographic database acquired between 1993 and 2007 was screened for patients with grade 1 or 2+ AR who had undergone follow up echocardiography at least one year later. The AR severity was graded as 1 to 4+, and any annual changes in AR grade were monitored. Among a total of 4,128 patients identified, 3,266 had grade 1+ AR and 862 had grade 2+ AR on the initial echocardiogram: the mean age was 67 +/- 15 years, and the duration of follow up was 4.2 +/- 2.7 years. Of those patients initially with grade 1+ AR, 95% showed no change in AR over a mean interval of 4.2 years, with an annual average increase in AR grade of 0.04. Of those patients initially with grade 2+ AR, 90% showed no change over this period, with an annual average increase in grade of 0.07. In the entire cohort, the AR progression correlated positively with age (p = 0.03), ventricular septal thickness (p grade 1 or 2+ AR in the absence of any higher risk for progression, such as grade 2+ AR combined with any degree of aortic stenosis and advanced age.

Amphibious Shear Velocity Structure of the Cascadia Subduction Zone

Science.gov (United States)

Janiszewski, H. A.; Gaherty, J. B.; Abers, G. A.; Gao, H.

2017-12-01

The amphibious Cascadia Initiative crosses the coastline of the Cascadia subduction zone (CSZ) deploying seismometers from the Juan de Fuca ridge offshore to beyond the volcanic arc onshore. This allows unprecedented seismic imaging of the CSZ, enabling examination of both the evolution of the Juan de Fuca plate prior to and during subduction as well as the along strike variability of the subduction system. Here we present new results from an amphibious shear velocity model for the crust and upper mantle across the Cascadia subduction zone. The primary data used in this inversion are surface-wave phase velocities derived from ambient-noise Rayleigh-wave data in the 10 - 20 s period band, and teleseismic earthquake Rayleigh wave phase velocities in the 20 - 160 s period band. Phase velocity maps from these data reflect major tectonic structures including the transition from oceanic to continental lithosphere, Juan de Fuca lithosphere that is faster than observations in the Pacific for oceanic crust of its age, slow velocities associated with the accretionary prism, the front of the fast subducting slab, and the Cascades volcanic arc which is associated with slower velocities in the south than in the north. Crustal structures are constrained by receiver functions in the offshore forearc and onshore regions, and by active source constraints on the Juan de Fuca plate prior to subduction. The shear-wave velocities are interpreted in their relationships to temperature, presence of melt or hydrous alteration, and compositional variation of the CSZ.

Fast and slow myosins as markers of muscle injury.

Science.gov (United States)

Guerrero, M; Guiu-Comadevall, M; Cadefau, J A; Parra, J; Balius, R; Estruch, A; Rodas, G; Bedini, J L; Cussó, R

2008-07-01

The diagnosis of muscular lesions suffered by athletes is usually made by clinical criteria combined with imaging of the lesion (ultrasonography and/or magnetic resonance) and blood tests to detect the presence of non-specific muscle markers. This study was undertaken to evaluate injury to fast and slow-twitch fibres using specific muscle markers for these fibres. Blood samples were obtained from 51 non-sports people and 38 sportsmen with skeletal muscle injury. Western blood analysis was performed to determine fast and slow myosin and creatine kinase (CK) levels. Skeletal muscle damage was diagnosed by physical examination, ultrasonography and magnetic resonance and biochemical markers. The imaging tests were found to be excellent for detecting and confirming grade II and III lesions. However, grade I lesions were often unconfirmed by these techniques. Grade I lesions have higher levels of fast myosin than slow myosin with a very small increase in CK levels. Grade II and III lesions have high values of both fast and slow myosin. The evaluation of fast and slow myosin in the blood 48 h after the lesion occurs is a useful aid for the detection of type I lesions in particular, since fast myosin is an exclusive skeletal muscle marker. The correct diagnosis of grade I lesions can prevent progression of the injury in athletes undergoing continual training sessions and competitions, thus aiding sports physicians in their decision making.

Network Medicine for Alzheimer's Disease and Traditional Chinese Medicine.

Science.gov (United States)

Jarrell, Juliet T; Gao, Li; Cohen, David S; Huang, Xudong

2018-05-11

Alzheimer’s Disease (AD) is a neurodegenerative condition that currently has no known cure. The principles of the expanding field of network medicine (NM) have recently been applied to AD research. The main principle of NM proposes that diseases are much more complicated than one mutation in one gene, and incorporate different genes, connections between genes, and pathways that may include multiple diseases to create full scale disease networks. AD research findings as a result of the application of NM principles have suggested that functional network connectivity, myelination, myeloid cells, and genes and pathways may play an integral role in AD progression, and may be integral to the search for a cure. Different aspects of the AD pathology could be potential targets for drug therapy to slow down or stop the disease from advancing, but more research is needed to reach definitive conclusions. Additionally, the holistic approaches of network pharmacology in traditional Chinese medicine (TCM) research may be viable options for the AD treatment, and may lead to an effective cure for AD in the future.

Distinct slow and fast cortical theta dynamics in episodic memory retrieval.

Science.gov (United States)

Pastötter, Bernhard; Bäuml, Karl-Heinz T

2014-07-01

Brain oscillations in the theta frequency band (3-8 Hz) have been shown to be critically involved in human episodic memory retrieval. In prior work, both positive and negative relationships between cortical theta power and retrieval success have been reported. This study examined the hypothesis that slow and fast cortical theta oscillations at the edges of the traditional theta frequency band are differentially related to retrieval success. Scalp EEG was recorded in healthy human participants as they performed a cued-recall episodic memory task. Slow (~3 Hz) and fast (~7 Hz) theta oscillations at retrieval were examined as a function of whether an item was recalled or not and as a function of the items' output position at test. Recall success typically declines with output position, due to increases in interference level. The results showed that slow theta power was positively related but fast theta power was negatively related to retrieval success. Concurrent positive and negative episodic memory effects for slow and fast theta oscillations were dissociable in time and space, showing different time courses and different spatial locations on the scalp. Moreover, fast theta power increased from early to late output positions, whereas slow theta power was unaffected by items' output position. Together with prior work, the results suggest that slow and fast theta oscillations have distinct functional roles in episodic memory retrieval, with slow theta oscillations being related to processes of recollection and conscious awareness, and fast theta oscillations being linked to processes of interference and interference resolution. Copyright © 2014 Elsevier Inc. All rights reserved.

Simulation and Comparison Between Slow and Fast FH/BPSK Spread Spectrum Using Matlab

Directory of Open Access Journals (Sweden)

Sanaa Said Kadhim

2018-02-01

Full Text Available This paper investigates the properties and applications of Frequency Hopping Spread Spectrum (FHSS.  FHSS is radio communication technique by which the sender of information sends the data on a radio channel, which changes the frequency of transmission based on a predetermined sequence of code. The FHSS has many advantages over traditional modulation methods, it can overcome fading, multipath channels and interferences. Hence the interception becomes difficult. This security feature makes FHSS more preferable for  military applications. At the receiver side, the signal is demodulated by the same carrier signal for which frequency changes by the same code sequences used by the sender. This paper presents two types of FHSS, slow and fast. The  simulation procedures of both types were  implemented and applied on   Frequency Hopping /Binary Phase Shift Keying (FH/BPSK spread spectrum system using MATLAB. The simulation sequences for fast and slow frequency hopping is the same in number  and frequencies of spreading carriers and both used BPSK traditional modulation type. The  comparison  results  based on their power spectral density   show that the fast frequency hopping is more resistive to noise the slow one.

Genetics Home Reference: progressive supranuclear palsy

Science.gov (United States)

... slow and slurred speech (dysarthria) and trouble swallowing (dysphagia). Most affected individuals also experience changes in personality ... UK): Treatment of Progressive Supranuclear Palsy Partners in Parkinson's: Movement Disorder Specialist Finder University of California, San ...

Velocity measurements in the near field of a diesel fuel injector by ultrafast imagery

Science.gov (United States)

Sedarsky, David; Idlahcen, Saïd; Rozé, Claude; Blaisot, Jean-Bernard

2013-02-01

This paper examines the velocity profile of fuel issuing from a high-pressure single-orifice diesel injector. Velocities of liquid structures were determined from time-resolved ultrafast shadow images, formed by an amplified two-pulse laser source coupled to a double-frame camera. A statistical analysis of the data over many injection events was undertaken to map velocities related to spray formation near the nozzle outlet as a function of time after start of injection. These results reveal a strong asymmetry in the liquid profile of the test injector, with distinct fast and slow regions on opposite sides of the orifice. Differences of ˜100 m/s can be observed between the `fast' and `slow' sides of the jet, resulting in different atomization conditions across the spray. On average, droplets are dispersed at a greater distance from the nozzle on the `fast' side of the flow, and distinct macrostructure can be observed under the asymmetric velocity conditions. The changes in structural velocity and atomization behavior resemble flow structures which are often observed in the presence of string cavitation produced under controlled conditions in scaled, transparent test nozzles. These observations suggest that widely used common-rail supply configurations and modern injectors can potentially generate asymmetric interior flows which strongly influence diesel spray morphology. The velocimetry measurements presented in this work represent an effective and relatively straightforward approach to identify deviant flow behavior in real diesel sprays, providing new spatially resolved information on fluid structure and flow characteristics within the shear layers on the jet periphery.

Comparing slow and fast rupture in laboratory experiments

Science.gov (United States)

Aben, F. M.; Brantut, N.; David, E.; Mitchell, T. M.

2017-12-01

During the brittle failure of rock, elastically stored energy is converted into a localized fracture plane and surrounding fracture damage, seismic radiation, and thermal energy. However, the partitioning of energy might vary with the rate of elastic energy release during failure. Here, we present the results of controlled (slow) and dynamic (fast) rupture experiments on dry Lanhélin granite and Westerly granite samples, performed under triaxial stress conditions at confining pressures of 50 and 100 MPa. During the tests, we measured sample shortening, axial load and local strains (with 2 pairs of strain gauges glued directly onto the sample). In addition, acoustic emissions (AEs) and changes in seismic velocities were monitored. The AE rate was used as an indicator to manually control the axial load on the sample to stabilize rupture in the quasi-static failure experiments. For the dynamic rupture experiments a constant strain rate of 10-5 s-1 was applied until sample failure. A third experiment, labeled semi-controlled rupture, involved controlled rupture up to a point where the rupture became unstable and the remaining elastic energy was released dynamically. All experiments were concluded after a macroscopic fracture had developed across the whole sample and frictional sliding commenced. Post-mortem samples were epoxied, cut and polished to reveal the macroscopic fracture and the surrounding damage zone. The samples failed with average rupture velocities varying from 5x10-6 m/s up to >> 0.1 m/s. The analyses of AE locations on the slow ruptures reveal that within Westerly granite samples - with a smaller grain size - fracture planes are disbanded in favor of other planes when a geometrical irregularity is encountered. For the coarser grained Lanhélin granite a single fracture plane is always formed, although irregularities are recognized as well. The semi-controlled experiments show that for both rock types the rupture can become unstable in response to these

Musical rhythms and their influence on P300 velocity in young females.

Science.gov (United States)

Sá, Cintia Ishii de; Pereira, Liliane Desguado

2011-01-01

Exposure to music may be useful in the P300 retest and avoid habituation. To verify the influence of the exposure to different kinds of music in P300 in young females. Clinical prospective. Forty-five women aged from 20 to 36 years were evaluated. P300 was studied before and after musical stimulation with different rhythms. Brazilian songs, international songs, and classical music melodies were selected. Each song had its velocity altered and was named as fast and slow. Subjects were divided into 2 groups exposed to music: one group was exposed to the fast version and the other to the slow version. The control group not exposed to music and was evaluated within the same time period of the others. There were statistically significant differences when comparing P300 amplitude in the first and third stimulation with the comparison group. In the same subject, several sequential registrations of P300 caused habituation, which was not seen during exposure to music before P300 recording. Exposure to music at preset different velocities did not affect the P300 in young females.

SPECTROSCOPIC OBSERVATIONS OF SN 2012fr: A LUMINOUS, NORMAL TYPE Ia SUPERNOVA WITH EARLY HIGH-VELOCITY FEATURES AND A LATE VELOCITY PLATEAU

International Nuclear Information System (INIS)

Childress, M. J.; Scalzo, R. A.; Sim, S. A.; Tucker, B. E.; Yuan, F.; Schmidt, B. P.; Cenko, S. B.; Filippenko, A. V.; Silverman, J. M.; Contreras, C.; Hsiao, E. Y.; Phillips, M.; Morrell, N.; Jha, S. W.; McCully, C.; Anderson, J. P.; De Jaeger, T.; Forster, F.; Benetti, S.; Bufano, F.

2013-01-01

We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II λ6355 line that can be cleanly decoupled from the lower velocity ''photospheric'' component. This Si II λ6355 HVF fades by phase –5; subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of ∼12,000 km s –1 until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at v ≈ 12,000 km s –1 with narrow line width and long velocity plateau, as well as an HVF beginning at v ≈ 31,000 km s –1 two weeks before maximum. SN 2012fr resides on the border between the ''shallow silicon'' and ''core-normal'' subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the ''low velocity gradient'' group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.

Treatment in patients with osteoarthritis at different sites: Place of slow-acting drugs

Directory of Open Access Journals (Sweden)

N. V. Chichasova

2015-01-01

Full Text Available The main goal of osteoarthritis (OA treatment is to perform rational analgesic and anti-inflammatory therapy, to slow down the progression of the disease, and to preserve quality of life in patients. The performance of analgesic therapy in the elderly is impeded by the presence of a concomitant disease, primarily that of the cardiovascular system and gastrointestinal tract. A group of experts has elaborated the algorithm for managing OA patients, which tracks a careful approach to using nonsteroidal anti-inflammatory drugs and confirms the efficacy of slow-acting agents (chondroitin sulfate (CS and glucosamine and intraarticular hyaluronate. The experts have concluded that the use of symptomatic slow-acting drugs for the treatment of OA (SYSADOA, if need be, in combination with short-term paracetanol cycles as basic therapy for this condition is safer and more effective. The 2003 EULAR guidelines identify CS and glucosamine as chondroprotectors. Many studies have shown that CS and glucosamine have a moderate or significant effect on joint pain syndrome and functional mobility in OA; they are safe and characterized by minimal side effects. Long-term qualitative randomized controlled trials have demonstrated that CS and glucosamine are able to slow down the progression of joint space narrowing in OA. It is also shown that the use of a combination of glucosamine and CS allows cartilage loss to be prevented.

Incident ion charge state dependence of electron emission during slow multicharged ion-surface interactions

International Nuclear Information System (INIS)

Hughes, I.G.; Zeijlmans van Emmichoven, P.A.; Havener, C.C.; Overbury, S.H.; Robinson, M.T.; Zehner, D.M.; Meyer, F.W.

1992-01-01

Characteristic variations in the total electron yield γ as a function of crystal azimuthal orientation are reported for slow N 2+ , N 5+ and N 6+ ions incident on a Au(011) single crystal, together with measurements of γ as a function of incident ion velocity. Kinetic electron emission is shown to arise predominantly in close collisions between incident ions and target atoms, and potential electron emission is found to be essentially constant within our present velocity range. The incident ion charge state is shown to play no role in kinetic electron emission. Extremely fast neutralization times of the order of 10 - 15 secs are needed to explain the observations

Visualization of mole fraction distribution of slow jet forming stably stratified field

International Nuclear Information System (INIS)

Fumizawa, Motoo; Hishida, Makoto

1990-01-01

An experimental study has been performed to investigate the behavior of flow and mass transfer in gaseous slow jet in which buoyancy force opposed the flow forming stably stratified field. The study has been performed to understand the basic features of air ingress phenomena at pipe rupture accident of the high temperature gas-cooled reactor. A displacement fringe technique was adopted in Mach-Zehnder interferometer to visualize the mole fraction distribution. As the result, the followings were obtained: (1) The stably stratified fields were formed in the vicinity of the outlet of the slow jet. The penetration distance of the stably stratified fields increased with Froude number. (2) Mass fraction distributions in the stably stratified fields were well correlated with the present model using the ramp mole velocity profile. (author)

A sextupole-magnet as variable velocity selector for paramagnetic atomic beams in the thermal range

International Nuclear Information System (INIS)

Spindler, G.; Ebinghaus, H.; Steffens, E.

1974-01-01

The possibility of employing a sextupole-magnet as a velocity selector on account of its velocity dependent focusing properties for paramagnetic atomic beams is investigated. In comparison with a traditional velocity selector with rotating disks, a sextupole-magnet as velocity selector has the advantage of additional focusing and polarizing the atomic beam. Moreover it suppresses polymer molecules without an effective magnetic momentum of the electronic shell

A low-neutron background slow-positron source

International Nuclear Information System (INIS)

White, M. M.

1998-01-01

The addition of a thermionic rf gun [1] and a photocathode rf gun will allow the Advanced Photon Source (APS) linear accelerator (linac) [2] [3] to become a free-electron laser (FEL) driver [4]. As the FEL project progresses, the existing high-charge DC thermionic gun will no longer be critical to APS operation and could be used to generate high-energy or low-energy electrons to drive a slow-positron source. We investigated possibilities to create a useful low-energy source that could operate semi-independently and would have a low neutron background

Validity and reliability of simple measurement device to assess the velocity of the barbell during squats.

Science.gov (United States)

Lorenzetti, Silvio; Lamparter, Thomas; Lüthy, Fabian

2017-12-06

The velocity of a barbell can provide important insights on the performance of athletes during strength training. The aim of this work was to assess the validity and reliably of four simple measurement devices that were compared to 3D motion capture measurements during squatting. Nine participants were assessed when performing 2 × 5 traditional squats with a weight of 70% of the 1 repetition maximum and ballistic squats with a weight of 25 kg. Simultaneously, data was recorded from three linear position transducers (T-FORCE, Tendo Power and GymAware), an accelerometer based system (Myotest) and a 3D motion capture system (Vicon) as the Gold Standard. Correlations between the simple measurement devices and 3D motion capture of the mean and the maximal velocity of the barbell, as well as the time to maximal velocity, were calculated. The correlations during traditional squats were significant and very high (r = 0.932, 0.990, p squats and was less accurate. All the linear position transducers were able to assess squat performance, particularly during traditional squats and especially in terms of mean velocity and time to maximal velocity.

Recovery of slowed nerve conduction velocity in lead-exposed workers

Energy Technology Data Exchange (ETDEWEB)

Araki, S.; Honma, T.; Yanagihara, S.; Ushio, K.

1980-06-01

Maximum motor nerve conduction velocities in the median nerve (MCV) and blood lead (PbB) were repeatedly measured in 14 lead-exposed workers with an initial PbB from 0.7 to 4.0 ..mu..mol/kg (median 2.3 ..mu..mol/kg) for a period from 3 months to 7 years: A certain dose of Calcium Disodium Ethylenediaminetetraacetic Acid (CaEDTA) was injected intravenously into most of the subjects during the period. In seven subjects, MCV improved by more than 4 m/s during the observation period which involved the first two successive measurements of MCV and PbB, but the remaining seven subjects showed the minimal alteration (within +- 4.0 m/s). The initial value of MCV was significantly slower (P < 0.01) and the decrease in PbB was significantly greater (P < 0.05) in the group of subjects having shown the improvement of MCV by more than 4 m/s. The initial value of MCV was significant in determining the alteration in MCV in multiple regression analysis and, together with the change in PbB, explained 31% of the alteration in MCV between the first two successive measurements. The initial level of PbB, dose of CaEDTA, time interval between the measurements and age played no essential part in the alteration in MCV. The alteration in MCV throughout the whole observational period in each subject significantly correlated with the concurrent change in PbB (r = -0.573, P < 0.001).

Effect of Slow External Flow on Flame Spreading over Solid Material: Opposed Spreading over Polyethylene Wire Insulation

Science.gov (United States)

Fujita, O.; Nishizawa, K.; Ito, K.; Olson, S. L.; Kashigawa, T.

2001-01-01

The effect of slow external flow on solid combustion is very important from the view of fire safety in space because the solid material in spacecraft is generally exposed to the low air flow for ventilation. Further, the effect of low external flow on fuel combustion is generally fundamental information for industrial combustion system, such as gas turbine, boiler incinerator and so on. However, it is difficult to study the effect of low external flow on solid combustion in normal gravity, because the buoyancy-induced flow strongly disturbs the flow field, especially for low flow velocity. In this research therefore, the effect of slow external flow on opposed flame spreading over polyethylene (PE) wire insulation have been investigated in microgravity. The microgravity environment was provided by Japan Microgravity Center (JAMIC) in Japan and KC-135 at NASA GRC. The tested flow velocity range is 0-30cm/s with different oxygen concentration and inert gas component.

Controllable group velocity of the probe light in a Λ-type system with two fold levels

International Nuclear Information System (INIS)

Jin Lihui; Gong Shangqing; Niu Yueping; Li Ruxin; Jin Shiqi

2006-01-01

The group velocities of the probe laser field are studied in a Λ-type system where one lower state has two fold levels coupled by a control field. It is found that the interaction of double dark states leads to controllable group velocity of the probe field in this system. It can be easily realized, due to the interacting double dark resonances, that one of the group velocities at transparency positions is much slower than the other by tuning the control field to be off resonance. In particular, when the control field is on resonance, we can obtain two equal slow group velocities with a broader EIT width, which provides potential applications in quantum storage and retrieval of light

MODELING OF REFLECTIVE PROPAGATING SLOW-MODE WAVE IN A FLARING LOOP

Energy Technology Data Exchange (ETDEWEB)

Fang, X.; Yuan, D.; Van Doorsselaere, T.; Keppens, R.; Xia, C. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, B-3001 Leuven (Belgium)

2015-11-01

Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in extreme ultraviolet images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed their association with persistent coronal upflows, making this interpretation debatable. We perform a 2.5D magnetohydrodynamic simulation to imitate the chromospheric evaporation and the following reflected patterns in a flare loop. Our model encompasses the corona, transition region, and chromosphere. We demonstrate that the quasi periodic propagating intensity variations captured by the synthesized Solar Dynamics Observatory/Atmospheric Imaging Assembly 131, 94 Å emission images match the previous observations well. With particle tracers in the simulation, we confirm that these quasi periodic propagating intensity variations consist of reflected slow mode waves and mass flows with an average speed of 310 km s{sup −1} in an 80 Mm length loop with an average temperature of 9 MK. With the synthesized Doppler shift velocity and intensity maps of the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation Fe xix line emission, we confirm that these reflected slow mode waves are propagating waves.

Appraisal and standardization of curvilinear velocity (VCL) cut-off values for CASA analysis of Japanese quail (Coturnix japonica) sperm.

Science.gov (United States)

Farooq, U; Malecki, I A; Mahmood, M; Martin, G B

2017-06-01

One of the basic steps in objective analysis of sperm motility is the subdivision of a motile sperm population into slow, medium and rapid categories based on their velocity. However, for CASA analysis of quail sperm, the velocity values for categorization of slow, medium and rapid sperm have not yet been standardized. To identify the cut-off values of "velocity curvilinear" (VCL) for quail sperm categorization, we captured and analysed 22,300 tracks of quail sperm using SCA ® -CASA. The median and mean VCL values were 85 and 97 μm/s. To define the VCL cut-off values, we used two methods. In the first, we identified the upper (rapid sperm) and lower (slow sperm) cut-off values using: (i) median VCL ± 25% or ± 50% or ± 75% of median VCL value; (ii) first and third quartile values of VCL data (i.e. 25% cut-off setting); and (iii) 33% and 66% of VCL data. Among these settings, sperm categories and their corresponding motility characteristics recorded using the "25%" setting (i.e. slow ≤36 ≤ medium ≤154 ≤ rapid) were found the most realistic and coherent with male ranking by fertility. In the second method, we calculated heteroscedasticity in the total VCL data using PCA and the two-step clustering method. With this approach, the mean of the high and low clusters was 165 and 51 μm/s, respectively. Together, the mean from two methods suggested that, for SCA ® -CASA categorization of quail sperm, sperm should be classed as "rapid" at VCL ≥160 μm/s and "slow" at VCL ≤45 μm/s. © 2017 Blackwell Verlag GmbH.

Secular slowing auditory simple reaction time in Sweden (1959-1985

Directory of Open Access Journals (Sweden)

Guy Madison

2016-08-01

Full Text Available There are indications that simple reaction time might have slowed in Western countries, based on both cohort- and multi-study comparisons. A possible limitation of the latter method in particular is measurement error stemming from methods variance, which results from the fact that instruments and experimental conditions change over time and between studies. We therefore set out to measure the simple auditory reaction time (SRT of 7,081 individuals (2,997 males and 4,084 females born in Sweden 1959-1985 (subjects were aged between 27 and 54 years at time of measurement. Depending on cut-offs and adjustment for ageing related slowing on SRT, the data suggest that SRT has increased between 3 and 16 ms in the 27 birth years covered in the present sample. The slowing is unlikely to be explained by attrition, as evaluated by comparing the general intelligence × birth-year interactions and standard deviations for both male participants and dropouts, utilizing military conscript cognitive ability data. The present result is consistent with previous studies employing alternative methods, and may result from several synergistic factors, such as possible recent micro-evolutionary trends favouring lower g in Sweden and the effects of industrially produced neurotoxic substances on peripheral nerve conduction velocity.

Effect of slow, small movement on the vibration-evoked kinesthetic illusion.

Science.gov (United States)

Cordo, P J; Gurfinkel, V S; Brumagne, S; Flores-Vieira, C

2005-12-01

The study reported in this paper investigated how vibration-evoked illusions of joint rotation are influenced by slow (0.3 degrees /s), small (2-4 degrees ) passive rotation of the joint. Normal human adults (n=15) matched the perceived position of the left ("reference") arm with the right ("matching") arm while vibration (50 pps, 0.5 mm) was applied for 30 s to the relaxed triceps brachii of the reference arm. Both arms were constrained to rotate horizontally at the elbow. Three experimental conditions were investigated: (1) vibration of the stationary reference arm, (2) slow, small passive extension or flexion of the reference arm during vibration, and (3) slow, small passive extension or flexion of the reference arm without vibration. Triceps brachii vibration at 50 pps induced an illusion of elbow flexion. The movement illusion began after several seconds, relatively fast to begin with and gradually slowing down to a stop. On average, triceps vibration produced illusory motion at an average latency of 6.3 s, amplitude of 9.7 degrees , velocity of 0.6 degrees /s, and duration of 16.4 s. During vibration, slow, small ( approximately 0.3 degrees /s, 1.3 degrees ) passive rotations of the joint dramatically enhanced, stopped, or reversed the direction of illusory movement, depending on the direction of the passive joint rotation. However, the subjects' perceptions of these passive elbow rotations were exaggerated: 2-3 times the size of the actual movement. In the absence of vibration, the subjects accurately reproduced these passive joint rotations. We discuss whether the exaggerated perception of slow, small movement during vibration is better explained by contributions of non muscle spindle Ia afferents or by changes in the mechanical transmission of vibration to the receptor.

Velocity- and slip-dependent weakening on the Tohoku plate boundary fault: shallow coseismic slip facilitated by foreshock afterslip

Science.gov (United States)

Ito, Y.; Ikari, M.; Ujiie, K.; Kopf, A.

2016-12-01

Understanding of role of slow earthquakes as they relate to the occurrence of both megathrust earthquakes and tsunami earthquakes is necessary to mitigate these disasters in the near future. Laboratory shearing experiments is one of important approach to evaluate these relationships. Here, we use powdered gouge samples from JFAST (IODP Expedition 343) Hole C0019E, core sample 17R-1, which is the plate boundary fault zone in the Japan Trench subduction zone. In this region, both large coseismic slip during the 2011 Tohoku-Oki earthquake as well as discrete slow slip events (SSE) have occurred. Experiments were conducted in a single-direct shear apparatus under normal stress of 16 MPa, with total shear displacements of up to 16 mm. We evaluate both the velocity- and slip-dependence of friction by extracting the velocity-dependent friction parameters a, b, and Dc, and measuring the rate of change in friction coefficient with shear displacement as the slip-dependence of friction. We report that in friction experiments using the Tohoku fault zone samples, an increase in sliding velocity exceeding that of earthquake afterslip can induce a change from steady-state frictional strength or slip hardening friction to slip-weakening frictional behavior. Our results show that the slip weakening is observed when the slip velocity exceeds 1 x 10-6 m/s during our experiments, while steady-state frictional strength or slip hardening is observed below 1x10-6 m/s. In the Japan Trench region, two slow events were observed at the downdip edge of the mainshock coseismic slip zone (< 30 m) were observed. These are an episodic SSE with a slip velocity of 0.1 x 10-6, and afterslip after the largest foreshock with a slip velocity of 2 x 10-6 m/s. This suggests that the afterslip may have facilitated the large coseismic slip during the mainshock on the plate boundary fault of the Tohoku-Oki earthquake.

Nuclear lifetimes and the slowing down of heavy ions in solids

International Nuclear Information System (INIS)

Scherpenzeel, D.E.C.

1981-01-01

Nuclear lifetime measurements by means of the Doppler Shift Attenuation (DSA) method at low recoil velocities (β approximately less than 0.01) are notoriously difficult due to the observed strong dependence of the extracted lifetimes on the slowing-down material at low initial velocities. This is mainly caused by the lack of reliable stopping power data for these velocities and the absence of an adequate theory to compensate for that. This problem of the determination of the correct mean life for the lowest Jsup(π) = 4 + state of 22 Ne is solved by measurements with the coincident high-velocity DSA method. Excited nuclei of high initial velocity [β(0) approximately 0.05] are generated by the bombardment of light targets, such as 1 H, 2 H, 3 H and 4 He, with beams of heavy ions. The combination of high initial velocity and coincidence restriction offers many advantages over the conventional techniques. The coincident high-velocity DSA method is also used to determine mean lives of low-lying excited states of the silicon isotopes 28 29 30 Si. The observed Doppler patterns are analyzed with experimental stopping powers and the resulting mean lives range from about 25 fs to 4 ps. The mean lives of the first excited state of 18 O and some low-lying levels of 35 S are determined from Doppler patterns analyzed with experimental stopping powers. The present stopping results for O, Si and S ions in Mg are also analyzed in terms of the effective charge concept. It is concluded that at the present level of accuracy of about 5 % the obtained results are consistent with this concept. (Auth.)

Rotational velocities of low-mass stars

International Nuclear Information System (INIS)

Stauffer, J.B.; Hartmann, L.W.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

1986-01-01

The rotational velocities of stars provide important clues to how stars form and evolve. Yet until recently, studies of stellar rotation were limited to stars more massive than the sun. This is beginning to change, and an observational outline of the rotational velocity evolution of stars less massive than the sun can now be provided. Low-mass stars rotate slowly during the early stages of premain-sequence evolution, and spin up as they contract to the main sequence. This spin-up culminates in a brief period of very rapid rotation at an age of order 50 million years. Physical interpretation of this increase in rotation and the subsequent main-sequence spin-down are complicated by the possibility of differential internal rotation. The observed rapidity of spin-down among G dwarfs suggests that initially only the outer convective envelopes of these stars are slowed. The data suggest an intrinsic spread in angular momentum among young stars of the same mass and age, a spread which is apparently minimized by the angular-momentum loss mechanism in old low-mass stars. 83 references

Electron electric dipole moment experiment using electric-fieldquantized slow cesium atoms

Energy Technology Data Exchange (ETDEWEB)

Amini, Jason M.; Munger Jr., Charles T.; Gould, Harvey.

2007-04-05

A proof-of-principle electron electric dipole moment (e-EDM)experiment using slow cesium atoms, nulled magnetic fields, and electricfield quantization has been performed. With the ambient magnetic fieldsseen by the atoms reduced to less than 200 pT, an electric field of 6MV/m lifts the degeneracy between states of unequal lbar mF rbar and,along with the low (approximately 3 m/s) velocity, suppresses thesystematic effect from the motional magnetic field. The low velocity andsmall residual magnetic field have made it possible to induce transitionsbetween states and to perform state preparation, analysis, and detectionin regions free of applied static magnetic and electric fields. Thisexperiment demonstrates techniques that may be used to improve the e-EDMlimit by two orders of magnitude, but it is not in itself a sensitivee-EDM search, mostly due to limitations of the laser system.

Food therapy and medical diet therapy of Traditional Chinese Medicine

OpenAIRE

Qunli Wu; Xiaochun Liang

2018-01-01

Food therapy of traditional Chinese medicine aims to maintain balanced nutrition through diet. Medical diet therapy, however, is to achieve the balance of Yin and Yang through the combination of nutrition and medicine. Either “food therapy” or “medical diet therapy” aims to keep health, prevent disease, remove illness and slow aging. In recent years, both food therapy and medical diet therapy have been increasingly applied in clinical nutrition therapy. In terms of traditional Chinese food th...

Revealing the cluster of slow transients behind a large slow slip event.

Science.gov (United States)

Frank, William B; Rousset, Baptiste; Lasserre, Cécile; Campillo, Michel

2018-05-01

Capable of reaching similar magnitudes to large megathrust earthquakes [ M w (moment magnitude) > 7], slow slip events play a major role in accommodating tectonic motion on plate boundaries through predominantly aseismic rupture. We demonstrate here that large slow slip events are a cluster of short-duration slow transients. Using a dense catalog of low-frequency earthquakes as a guide, we investigate the M w 7.5 slow slip event that occurred in 2006 along the subduction interface 40 km beneath Guerrero, Mexico. We show that while the long-period surface displacement, as recorded by Global Positioning System, suggests a 6-month duration, the motion in the direction of tectonic release only sporadically occurs over 55 days, and its surface signature is attenuated by rapid relocking of the plate interface. Our proposed description of slow slip as a cluster of slow transients forces us to re-evaluate our understanding of the physics and scaling of slow earthquakes.

Epigenomic maintenance through dietary intervention can facilitate DNA repair process to slow down the progress of premature aging.

Science.gov (United States)

Ghosh, Shampa; Sinha, Jitendra Kumar; Raghunath, Manchala

2016-09-01

DNA damage caused by various sources remains one of the most researched topics in the area of aging and neurodegeneration. Increased DNA damage causes premature aging. Aging is plastic and is characterised by the decline in the ability of a cell/organism to maintain genomic stability. Lifespan can be modulated by various interventions like calorie restriction, a balanced diet of macro and micronutrients or supplementation with nutrients/nutrient formulations such as Amalaki rasayana, docosahexaenoic acid, resveratrol, curcumin, etc. Increased levels of DNA damage in the form of double stranded and single stranded breaks are associated with decreased longevity in animal models like WNIN/Ob obese rats. Erroneous DNA repair can result in accumulation of DNA damage products, which in turn result in premature aging disorders such as Hutchinson-Gilford progeria syndrome. Epigenomic studies of the aging process have opened a completely new arena for research and development of drugs and therapeutic agents. We propose here that agents or interventions that can maintain epigenomic stability and facilitate the DNA repair process can slow down the progress of premature aging, if not completely prevent it. © 2016 IUBMB Life, 68(9):717-721, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

Multidisk neutron velocity selectors

International Nuclear Information System (INIS)

Hammouda, B.

1992-01-01

Helical multidisk velocity selectors used for neutron scattering applications have been analyzed and tested experimentally. Design and performance considerations are discussed along with simple explanation of the basic concept. A simple progression is used for the inter-disk spacing in the 'Rosta' design. Ray tracing computer investigations are presented in order to assess the 'coverage' (how many absorbing layers are stacked along the path of 'wrong' wavelength neutrons) and the relative number of neutrons absorbed in each disk (and therefore the relative amount of gamma radiation emitted from each disk). We discuss whether a multidisk velocity selector can be operated in the 'reverse' configuration (i.e. the selector is turned by 180 0 around a vertical axis with the rotor spun in the reverse direction). Experimental tests and calibration of a multidisk selector are reported together with evidence that a multidisk selector can be operated in the 'reverse' configuration. (orig.)

Slowness Anomalies of PKP Phases Recorded at the Seismic Array in Eielson, Alaska (ILAR)

Science.gov (United States)

Koper, K. D.; Parker, V.

2005-12-01

The Eielson, Alaska seismic array (ILAR) is well situated to record PKPDF waves from earthquakes occurring in the South Sandwich Islands (SSI) region. Such ray paths are nearly aligned with Earth's rotation axis and are useful for constraining models of inner core anisotropy. The many previous studies of PKPDF waves traversing the SSI-Alaska corridor generally find waves that arrive several seconds faster than expected, with highly attenuated and often complicated shapes. Simple radially or cylindrically symmetric Earth models cannot explain these observations, and it may be the case that mantle heterogeneities are biasing the SSI-Alaska PKPDF waves. In this study, we take advantage of the small aperture of ILAR to make independent measurements of differential PKPDF-PKPBC travel times and differential PKPDF-PKPBC horizontal slowness vectors for 37 SSI earthquakes that occurred from 1996-2004. Anomalies in slowness (ray parameter and backazimuth) of a phase reflect heterogeneous Earth structure in a manner complementary to travel time anomalies. At a reference distance of 152°, we find a mean differential travel time residual of 3.1 ± 0.1~s, a mean differential ray parameter of 2.9±0.2~s/deg, and that PKPDF waves arrive from a backazimuth rotated approximately 10° counterclockwise relative to corresponding PKPBC waves. Joint modeling of the differential travel times and differential ray parameters indicates that (1) lower mantle heterogeneities are not responsible for the properties of PKPDF from SSI-ILAR, (2) the lower several hundred kilometers of the outer core has a slightly lower velocity, and/or velocity gradient, than current reference models, and (3) there is a strong, radial velocity gradient within the inner core at a radius of 600-900~km. However, the differential slowness anomalies cannot be fully explained by variations in deep Earth structure, implying that local site effects at ILAR are somewhat different for PKPDF and PKPBC phases.

Mössbauer spectra linearity improvement by sine velocity waveform followed by linearization process

Science.gov (United States)

Kohout, Pavel; Frank, Tomas; Pechousek, Jiri; Kouril, Lukas

2018-05-01

This note reports the development of a new method for linearizing the Mössbauer spectra recorded with a sine drive velocity signal. Mössbauer spectra linearity is a critical parameter to determine Mössbauer spectrometer accuracy. Measuring spectra with a sine velocity axis and consecutive linearization increases the linearity of spectra in a wider frequency range of a drive signal, as generally harmonic movement is natural for velocity transducers. The obtained data demonstrate that linearized sine spectra have lower nonlinearity and line width parameters in comparison with those measured using a traditional triangle velocity signal.

Experimental study on slow flexural waves around the defect modes in a phononic crystal beam using fiber Bragg gratings

Energy Technology Data Exchange (ETDEWEB)

Chuang, Kuo-Chih, E-mail: chuangkc@zju.edu.cn; Zhang, Zhi-Qiang; Wang, Hua-Xin

2016-12-09

Highlights: • Slow waves around the defect modes in a phononic crystal beam are validated. • A fiber Bragg grating displacement sensing system can measure the defect mode. • The defect mode is analyzed by a transfer matrix method with a supercell technique. - Abstract: This work experimentally studies influences of the point defect modes on the group velocity of flexural waves in a phononic crystal Timoshenko beam. Using the transfer matrix method with a supercell technique, the band structures and the group velocities around the defect modes are theoretically obtained. Particularly, to demonstrate the existence of the localized defect modes inside the band gaps, a high-sensitivity fiber Bragg grating sensing system is set up and the displacement transmittance is measured. Slow propagation of flexural waves via defect coupling in the phononic crystal beam is then experimentally demonstrated with Hanning windowed tone burst excitations.

Effects of slow breathing rate on heart rate variability and arterial baroreflex sensitivity in essential hypertension.

Science.gov (United States)

Li, Changjun; Chang, Qinghua; Zhang, Jia; Chai, Wenshu

2018-05-01

This study is to investigate the effects of slow breathing on heart rate variability (HRV) and arterial baroreflex sensitivity in essential hypertension.We studied 60 patients with essential hypertension and 60 healthy controls. All subjects underwent controlled breathing at 8 and 16 breaths per minute. Electrocardiogram, respiratory, and blood pressure signals were recorded simultaneously. We studied effects of slow breathing on heart rate, blood pressure and respiratory peak, high-frequency (HF) power, low-frequency (LF) power, and LF/HF ratio of HRV with traditional and corrected spectral analysis. Besides, we tested whether slow breathing was capable of modifying baroreflex sensitivity in hypertensive subjects.Slow breathing, compared with 16 breaths per minute, decreased the heart rate and blood pressure (all P hypertensive subjects. Slow breathing increased baroreflex sensitivity in hypertensive subjects (from 59.48 ± 6.39 to 78.93 ± 5.04 ms/mm Hg, P hypertension. Besides, slow breathing increased baroreflex sensitivity in hypertensive subjects. These demonstrate slow breathing is indeed capable of shifting sympatho-vagal balance toward vagal activities and increasing baroreflex sensitivity, suggesting a safe, therapeutic approach for essential hypertension.

[Effects of dauricine on action potentials and slow inward currents of guinea pig ventricular papillary muscles].

Science.gov (United States)

Li, S N; Zhang, K Y

1992-11-01

Effects of dauricine (Dau) on the action potentials (AP), the slow action potentials (SAP), and the slow inward currents (Isi) of guinea pig ventricular papillary muscles were observed by means of intracellular microelectrode and single sucrose gap voltage clamp technique. In the early stage, Dau shortened action potential duration 100 (APD100) and effective refractory period (ERP) (ERP/APD ERP, and APD20, significantly decreased action potential amplitude (APA), maximum velocity (Vmax), and overshot (OS) (ERP/APD > 1; P SAP induced by isoprenaline (P < 0.01), and remarkably inhibited Isi (P < 0.01). The results suggested that Dau exerted an inhibitory effect on Na+, Ca2+, and K+ channels.

ACUTE EFFECTS OF MOVEMENT VELOCITY ON BLOOD LACTATE AND GROWTH HORMONE RESPONSES AFTER ECCENTRIC BENCH PRESS EXERCISE IN RESISTANCE-TRAINED MEN

OpenAIRE

Calixto, RD; Verlengia, R; Crisp, AH; Carvalho, TB; Crepaldi, MD; Pereira, AA; Yamada, AK; da Mota, GR; Lopes, CR

2014-01-01

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric...

The slow cell death response when screening chemotherapeutic agents.

Science.gov (United States)

Blois, Joseph; Smith, Adam; Josephson, Lee

2011-09-01

To examine the correlation between cell death and a common surrogate of death used in screening assays, we compared cell death responses to those obtained with the sulforhodamine B (SRB) cell protein-based "cytotoxicity" assay. With the SRB assay, the Hill equation was used to obtain an IC50 and final cell mass, or cell mass present at infinite agent concentrations, with eight adherent cell lines and four agents (32 agent/cell combinations). Cells were treated with high agent concentrations (well above the SRB IC50) and the death response determined as the time-dependent decrease in cells failing to bind both annexin V and vital fluorochromes by flow cytometry. Death kinetics were categorized as fast (5/32) (similar to the reference nonadherent Jurkat line), slow (17/32), or none (10/32), despite positive responses in the SRB assay in all cases. With slow cell death, a single exposure to a chemotherapeutic agent caused a slow, progressive increase in dead (necrotic) and dying (apoptotic) cells for at least 72 h. Cell death (defined by annexin and/or fluorochrome binding) did not correlate with the standard SRB "cytotoxicity" assay. With the slow cell death response, a single exposure to an agent caused a slow conversion from vital to apoptotic and necrotic cells over at least 72 h (the longest time point examined). Here, increasing the time of exposure to agent concentrations modestly above the SRB IC50 provides a method of maximizing cell kill. If tumors respond similarly, sustained low doses of chemotherapeutic agents, rather than a log-kill, maximum tolerated dose strategy may be an optimal strategy of maximizing tumor cell death.

Range and stopping power for slow particles

International Nuclear Information System (INIS)

Bastiano, M.; Fernandez, J. E.; Molinari, V. G.

1997-01-01

Generally, the effects of thermal agitation and chemical bonding of the target atoms need to be taken into account to compute properly the range and stopping power of particles. These two effects, however, complicate very much the calculation of the above parameters, and for this reason are usually neglected. In fact, when the energy of the test particles (t.p.) is sufficiently high compared to the thermal or bonding energies, these two effects can be safely disregarded. When the energy of the t.p. is of the same order of the thermal agitation or the chemical bonding, on the other hand, such approximation is not realistic, and to obtain meaningful results one must take into account the velocity distribution of the field particles (f.p.). The aim of this paper is to present a simple model describing the transport of particles (e.g., electrons) in the thermal zone, considering the thermal agitation of f.p. with an arbitrary distribution. It will be shown that in the first part of the slowing down the kinetic energy of t.p. is partially transformed into temperature. In the second part, the temperature tends to reach the equilibrium temperature, while average velocity of t.p. becomes zero. (author)

Recent progress in annihilation related studies by slow positrons

International Nuclear Information System (INIS)

Lynn, K.G.

1989-01-01

The field of slow-positron physics has expanded significantly in the last few years to include particles and atomic physics but has been most extensive in those associated with condensed matter or material science. This can primarily be attributed to the development of more efficient moderators. These moderators have been associated with both laboratory- and facility-based beams. In this paper I will focus only on the material-science aspects however. Positron can and are being used to examine all of the various fields. I feel the contribution in all these areas will be significant. I will primarily discuss those developments that have been developed in the area of interface science; a field that has both scientific and technological importance and has a limited number of nondestructive probes used in studying a buried interface. Interfaces are technologically important for applications such as electrical properties and mechanical properties. Such applications help to motivate the fundamental research of interface properties and dynamics, which is necessary to develop the basic understanding of new types of interfaces. The role of the interface is also important since it limited length of this paper. Results will be presented in interface studies that have occurred in the last year, including some unpublished results obtained at Brookhaven over the past few months. This field is in the early stages and I expect that the full utilization of this relatively new probe can be anticipated in the next few years. 17 refs., 7 figs

A high-performance carbon derived from corn stover via microwave and slow pyrolysis for supercapacitors

DEFF Research Database (Denmark)

Jin, Hong; wang, Xiaomin; Shen, Yanbin

2014-01-01

Microwave and slow pyrolysis were conducted for converting corn stover to biochar. Chemical agents of sodium hydroxide and potassium hydroxide were used to progressively produce activated carbon. The pore structures and surface area of the samples were characterized by nitrogen adsorption....../desorption at 77 K. The results demonstrated that higher specific surface areas of activated carbons were obtained by microwave pyrolysis combined with potassium hydroxide activation. However, electrochemical measurements showed that the slow pyrolysis biochar treated with 0.05 mol g−1 (potassium hydroxide...

Optical-fiber interferometer for velocity measurements with picosecond resolution

International Nuclear Information System (INIS)

Weng Jidong; Tan Hua; Wang Xiang; Ma Yun; Hu Shaolou; Wang Xiaosong

2006-01-01

The conventional Doppler laser-interference velocimeters are made up of traditional optical elements such as lenses and mirrors and will generally restrict its applications in multipoint velocity measurements. By transfering the light from multimode optical fiber to single-mode optical fiber and using the currently available conventional telecommunications elements, the authors have constructed a velocimeter called all-fiber displacement interferometer system for any reflector. The unique interferometer system is only made up of fibers or fiber-coupled components. The viability of this technique is demonstrated by measuring the velocity of an interface moving at velocity of 2133 m/s with 50 ps time resolution. In addition, the concept of optical-fiber mode conversion would provide a way to develop various optical-fiber sensors

An Iterative Adaptive Approach for Blood Velocity Estimation Using Ultrasound

DEFF Research Database (Denmark)

Gudmundson, Erik; Jakobsson, Andreas; Jensen, Jørgen Arendt

2010-01-01

This paper proposes a novel iterative data-adaptive spectral estimation technique for blood velocity estimation using medical ultrasound scanners. The technique makes no assumption on the sampling pattern of the slow-time or the fast-time samples, allowing for duplex mode transmissions where B......-mode images are interleaved with the Doppler emissions. Furthermore, the technique is shown, using both simplified and more realistic Field II simulations, to outperform current state-of-the-art techniques, allowing for accurate estimation of the blood velocity spectrum using only 30% of the transmissions......, thereby allowing for the examination of two separate vessel regions while retaining an adequate updating rate of the B-mode images. In addition, the proposed method also allows for more flexible transmission patterns, as well as exhibits fewer spectral artifacts as compared to earlier techniques....

Sevoflurane Induces Coherent Slow-Delta Oscillations in Rats

Directory of Open Access Journals (Sweden)

Jennifer A. Guidera

2017-07-01

Full Text Available Although general anesthetics are routinely administered to surgical patients to induce loss of consciousness, the mechanisms underlying anesthetic-induced unconsciousness are not fully understood. In rats, we characterized changes in the extradural EEG and intracranial local field potentials (LFPs within the prefrontal cortex (PFC, parietal cortex (PC, and central thalamus (CT in response to progressively higher doses of the inhaled anesthetic sevoflurane. During induction with a low dose of sevoflurane, beta/low gamma (12–40 Hz power increased in the frontal EEG and PFC, PC and CT LFPs, and PFC–CT and PFC–PFC LFP beta/low gamma coherence increased. Loss of movement (LOM coincided with an abrupt decrease in beta/low gamma PFC–CT LFP coherence. Following LOM, cortically coherent slow-delta (0.1–4 Hz oscillations were observed in the frontal EEG and PFC, PC and CT LFPs. At higher doses of sevoflurane sufficient to induce loss of the righting reflex, coherent slow-delta oscillations were dominant in the frontal EEG and PFC, PC and CT LFPs. Dynamics similar to those observed during induction were observed as animals emerged from sevoflurane anesthesia. We conclude that the rat is a useful animal model for sevoflurane-induced EEG oscillations in humans, and that coherent slow-delta oscillations are a correlate of sevoflurane-induced behavioral arrest and loss of righting in rats.

Maintenance of Velocity and Power With Cluster Sets During High-Volume Back Squats.

Science.gov (United States)

Tufano, James J; Conlon, Jenny A; Nimphius, Sophia; Brown, Lee E; Seitz, Laurent B; Williamson, Bryce D; Haff, G Gregory

2016-10-01

To compare the effects of a traditional set structure and 2 cluster set structures on force, velocity, and power during back squats in strength-trained men. Twelve men (25.8 ± 5.1 y, 1.74 ± 0.07 m, 79.3 ± 8.2 kg) performed 3 sets of 12 repetitions at 60% of 1-repetition maximum using 3 different set structures: traditional sets (TS), cluster sets of 4 (CS4), and cluster sets of 2 (CS2). When averaged across all repetitions, peak velocity (PV), mean velocity (MV), peak power (PP), and mean power (MP) were greater in CS2 and CS4 than in TS (P < .01), with CS2 also resulting in greater values than CS4 (P < .02). When examining individual sets within each set structure, PV, MV, PP, and MP decreased during the course of TS (effect sizes 0.28-0.99), whereas no decreases were noted during CS2 (effect sizes 0.00-0.13) or CS4 (effect sizes 0.00-0.29). These results demonstrate that CS structures maintain velocity and power, whereas TS structures do not. Furthermore, increasing the frequency of intraset rest intervals in CS structures maximizes this effect and should be used if maximal velocity is to be maintained during training.

Slow briefs: slow food....slow architecture

OpenAIRE

Crotch, Joanna

2012-01-01

We are moving too fast…fast lives, fast cars, fast food…..and fast architecture. We are caught up in a world that allows no time to stop and think; to appreciate and enjoy all the really important things in our lives. Recent responses to this seemingly unstoppable trend are the growing movements of Slow Food and Cittaslow. Both initiatives are, within their own realms, attempting to reverse speed, homogeny, expediency and globalisation, considering the values of regionality, patience, craft, ...

Detailed seismic velocity structure of the ultra-slow spread crust at the Mid-Cayman Spreading Center from travel-time tomography and synthetic seismograms

Science.gov (United States)

Harding, J.; Van Avendonk, H. J.; Hayman, N. W.; Grevemeyer, I.; Peirce, C.

2017-12-01

The Mid-Cayman Spreading Center (MCSC), an ultraslow-spreading center in the Caribbean Sea, has formed highly variable oceanic crust. Seafloor dredges have recovered extrusive basalts in the axial deeps as well as gabbro on bathymetric highs and exhumed mantle peridotite along the only 110 km MCSC. Wide-angle refraction data were collected with active-source ocean bottom seismometers in April, 2015, along lines parallel and across the MCSC. Travel-time tomography produces relatively smooth 2-D tomographic models of compressional wave velocity. These velocity models reveal large along- and across-axis variations in seismic velocity, indicating possible changes in crustal thickness, composition, faulting, and magmatism. It is difficult, however, to differentiate between competing interpretations of seismic velocity using these tomographic models alone. For example, in some areas the seismic velocities may be explained by either thin igneous crust or exhumed, serpentinized mantle. Distinguishing between these two interpretations is important as we explore the relationships between magmatism, faulting, and hydrothermal venting at ultraslow-spreading centers. We therefore improved our constraints on the shallow seismic velocity structure of the MCSC by modeling the amplitude of seismic refractions in the wide-angle data set. Synthetic seismograms were calculated with a finite-difference method for a range of models with different vertical velocity gradients. Small-scale features in the velocity models, such as steep velocity gradients and Moho boundaries, were explored systematically to best fit the real data. With this approach, we have improved our understanding of the compressional velocity structure of the MCSC along with the geological interpretations that are consistent with three seismic refraction profiles. Line P01 shows a variation in the thinness of lower seismic velocities along the axis, indicating two segment centers, while across-axis lines P02 and P03

Radiation efficiency during slow crack propagation: an experimental study.

Science.gov (United States)

Jestin, Camille; Lengliné, Olivier; Schmittbuhl, Jean

2017-04-01

Creeping faults are known to host a significant aseismic deformation. However, the observations of micro-earthquake activity related to creeping faults (e.g. San Andreas Faults, North Anatolian Fault) suggest the presence of strong lateral variabilities of the energy partitioning between radiated and fracture energies. The seismic over aseismic slip ratio is rather difficult to image over time and at depth because of observational limitations (spatial resolution, sufficiently broad band instruments, etc.). In this study, we aim to capture in great details the energy partitioning during the slow propagation of mode I fracture along a heterogeneous interface, where the toughness is strongly varying in space.We lead experiments at laboratory scale on a rock analog model (PMMA) enabling a precise monitoring of fracture pinning and depinning on local asperities in the brittle-creep regime. Indeed, optical imaging through the transparent material allows the high resolution description of the fracture front position and velocity during its propagation. At the same time, acoustic emissions are also measured by accelerometers positioned around the rupture. Combining acoustic records, measurements of the crack front position and the loading curve, we compute the total radiated energy and the fracture energy. We deduce from them the radiation efficiency, ηR, characterizing the proportion of the available energy that is radiated in form of seismic wave. We show an increase of ηR with the crack rupture speed computed for each of our experiments in the sub-critical crack propagation domain. Our experimental estimates of ηR are larger than the theoretical model proposed by Freund, stating that the radiation efficiency of crack propagation in homogeneous media is proportional to the crack velocity. Our results are demonstrated to be in agreement with existing studies which showed that the distribution of crack front velocity in a heterogeneous medium can be well described by a

The Analysis and Calculation Method of Urban Rail Transit Carrying Capacity Based on Express-Slow Mode

Directory of Open Access Journals (Sweden)

Xiaobing Ding

2016-01-01

Full Text Available Urban railway transport that connects suburbs and city areas is characterized by uneven temporal and spatial distribution in terms of passenger flow and underutilized carrying capacity. This paper aims to develop methodologies to measure the carrying capacity of the urban railway by introducing a concept of the express-slow mode. We first explore factors influencing the carrying capacity under the express-slow mode and the interactive relationships among these factors. Then we establish seven different scenarios to measure the carrying capacity by considering the ratio of the number of the express trains and the slow trains, the station where overtaking takes place, and the number of overtaking maneuvers. Taking Shanghai Metro Line 16 as an empirical study, the proposed methods to measure the carrying capacity under different express-slow mode are proved to be valid. This paper contributes to the literature by remodifying the traditional methods to measure the carrying capacity when different express-slow modes are applied to improve the carrying capacity of the suburban railway.

Welding wire velocity modelling and control using an optical sensor

DEFF Research Database (Denmark)

Nielsen, Kirsten M.; Pedersen, Tom S.

2007-01-01

In this paper a method for controlling the velocity of a welding wire at the tip of the handle is described. The method is an alternative to the traditional welding apparatus control system where the wire velocity is controlled internal in the welding machine implying a poor disturbance reduction....... To obtain the tip velocity a dynamic model of the wire/liner system is developed and verified.  In the wire/liner system it turned out that backlash and reflections are influential factors. An idea for handling the backlash has been suggested. In addition an optical sensor for measuring the wire velocity...... at the tip has been constructed. The optical sensor may be used but some problems due to focusing cause noise in the control loop demanding a more precise mechanical wire feed system or an optical sensor with better focusing characteristics....

Hydro-Mechanical Modelling of Slow Slip Phenomena at the Subduction Interface.

Science.gov (United States)

Petrini, C.; Gerya, T.; Madonna, C.; van Dinther, Y.

2016-12-01

Subduction zones experience a spectrum of slip phenomena, ranging from large devastating megathrust earthquakes to aseismic slow slip events. Slow slip events, lasting hours to years and being perceptible only by instruments, are believed to have the capability to induce large earthquakes. It is also repeatedly proposed that such slow events are controlled by fluid-rock interactions along the subduction interface, thus calling for development of fully coupled seismo-hydro-mechanical modeling approaches to identify their physics and controlling parameters. We present a newly developed finite difference visco-elasto-plastic numerical code with marker-in-cell technique, which fully couples mechanical deformation and fluid flow. We use this to investigate how the presence of fluids in the pore space of a (de)compacting rock matrix affects elastic stress accumulation and release along a fluid-bearing subduction interface. The model simulates the spontaneous occurrence of quasi-periodic slow slip phenomena along self-consistently forming highly localized shearbands, which accommodate shear displacement between two plates. The produced elastic rebound events show a slip velocity on the order of cm/yr, which is in good agreement with measured data. The governing gradual strength decrease along the slowly propagating shear bands is related to a drop in total pressure caused by shear localization at nearly constant (slightly decreasing) fluid pressure. Gradual reduction of the difference between the total and fluid pressure decreases brittle/plastic strength of fluid-bearing rocks along the shear bands, thus providing a dynamic feedback mechanism for the accumulated elastic stress release at the subduction interface.

Stall in Women's Real Wage Growth Slows Progress in Closing the Wage Gap. Briefing Paper.

Science.gov (United States)

Hartmann, Heidi; Whittaker, Julie

Since 1979, the wage gap between women and men has narrowed significantly, falling by more than 10 percent overall. The closing of the wage gap has slowed considerably in the 1990's, however, with women's real wages (adjusted for inflation) stagnating in recent year and men's wages continuing to decline. The lack of growth in both women's and…

Academic Progress of Students across Inclusive and Traditional Settings

Science.gov (United States)

Cole, Cassandra M.; Waldron, Nancy; Majd, Massoumeh

2004-01-01

Effects of inclusive school settings for students in six Indiana school corporations were investigated. Results reveal that students without disabilities educated in inclusive settings made significantly greater academic progress in mathematics and reading. For students with disabilities, there were no significant differences in reading and math…

An Intrinsic Value System for Developing Multiple Invariant Representations with Incremental Slowness Learning

Directory of Open Access Journals (Sweden)

Matthew David Luciw

2013-05-01

Full Text Available Curiosity Driven Modular Incremental Slow Feature Analysis (CD-MISFA;~cite{cdmisfa} is a recently introduced model of intrinsically-motivated invariance learning, which shows how curiosity enables the orderly formation of multiple stable sensory representations, through which the agent can simplify its complex sensory input. Here, we first discuss the computational properties of the CD-MISFA model itself, followed by a discussion of neurophysiological analogs fulfilling similar functional roles. CD-MISFA combines 1. unsupervised representation learning through the slowness principle, 2. generation of an intrinsic reward signal through the learning progress of the developing features, and 3. balancing of exploration and exploitation in order to maximize learning progress and quickly learn multiple feature sets for perceptual simplification. Experimental results on synthetic observations and on the iCub robot show that the intrinsic value system is an essential component to representation learning, further, the model explores such that the representations are typically learned in order from least to most costly, as predicted by the theory of Artificial Curiosity.

The 2012 Mw5.6 earthquake in Sofia seismogenic zone - is it a slow earthquake

Science.gov (United States)

Raykova, Plamena; Solakov, Dimcho; Slavcheva, Krasimira; Simeonova, Stela; Aleksandrova, Irena

2017-04-01

very low rupture velocity. The low rupture velocity can mean slow-faulting, which brings to slow release of accumulated seismic energy. The slow release energy does principally little to moderate damages. Additionally wave form of the earthquake shows low frequency content of P-waves (the maximum P-wave is at 1.19 Hz) and the specific P- wave displacement spectral is characterise with not expressed spectrum plateau and corner frequency. These and other signs suggest us to the conclusion, that the 2012 Mw5.6 earthquake can be considered as types of slow earthquake, like a low frequency quake. The study is based on data from Bulgarian seismological network (NOTSSI), the local network (LSN) deployed around Kozloduy NPP and System of Accelerographs for Seismic Monitoring of Equipment and Structures (SASMES) installed in the Kozloduy NPP. NOTSSI jointly with LSN and SASMES provide reliable information for multiple studies on seismicity in regional scale.

A California statewide three-dimensional seismic velocity model from both absolute and differential times

Science.gov (United States)

Lin, G.; Thurber, C.H.; Zhang, H.; Hauksson, E.; Shearer, P.M.; Waldhauser, F.; Brocher, T.M.; Hardebeck, J.

2010-01-01

We obtain a seismic velocity model of the California crust and uppermost mantle using a regional-scale double-difference tomography algorithm. We begin by using absolute arrival-time picks to solve for a coarse three-dimensional (3D) P velocity (VP) model with a uniform 30 km horizontal node spacing, which we then use as the starting model for a finer-scale inversion using double-difference tomography applied to absolute and differential pick times. For computational reasons, we split the state into 5 subregions with a grid spacing of 10 to 20 km and assemble our final statewide VP model by stitching together these local models. We also solve for a statewide S-wave model using S picks from both the Southern California Seismic Network and USArray, assuming a starting model based on the VP results and a VP=VS ratio of 1.732. Our new model has improved areal coverage compared with previous models, extending 570 km in the SW-NE directionand 1320 km in the NW-SE direction. It also extends to greater depth due to the inclusion of substantial data at large epicentral distances. Our VP model generally agrees with previous separate regional models for northern and southern California, but we also observe some new features, such as high-velocity anomalies at shallow depths in the Klamath Mountains and Mount Shasta area, somewhat slow velocities in the northern Coast Ranges, and slow anomalies beneath the Sierra Nevada at midcrustal and greater depths. This model can be applied to a variety of regional-scale studies in California, such as developing a unified statewide earthquake location catalog and performing regional waveform modeling.

The superconductor revolutions and the (slow) applications evolution

International Nuclear Information System (INIS)

Foner, S.

1990-01-01

The discovery in the 1960's of type 2 superconductors with high critical current densities in high magnetic fields (and the development of NbTi in particular) led to the first revolution. The discovery of high temperature superconductors (HTS) started the second revolution. At this stage ceramists became involved with superconductors. I will assess the status of various superconductor applications, progress of HTS and their possible applications at 4.2K, and near-term needs for superconducting materials operating at 30T in specialized facilities. Reasons for the slow growth of superconductor applications will be reviewed

Slow electron motion in condensed matter: Final progress report for period January 1, 1984-December 31, 1986

International Nuclear Information System (INIS)

Fano, U.

1987-02-01

A summary is given for theoretical procedures that describe and evaluate the penetration, degradation and diffusion of slow electrons in condensed matter with characteristics relevant to biological systems. 5 refs

Hydrogen bonds as molecular timers for slow inactivation in voltage-gated potassium channels

DEFF Research Database (Denmark)

Pless, Stephan Alexander; Galpin, Jason D; Niciforovic, Ana P

2013-01-01

Voltage-gated potassium (Kv) channels enable potassium efflux and membrane repolarization in excitable tissues. Many Kv channels undergo a progressive loss of ion conductance in the presence of a prolonged voltage stimulus, termed slow inactivation, but the atomic determinants that regulate the k...... subunit(s). DOI: http://dx.doi.org/10.7554/eLife.01289.001....

The influence of interstitial water velocity on the migration of 85Sr and 137Cs in an aerated sandy soil layer

International Nuclear Information System (INIS)

Ohnuki, Toshihiko; Takebe, Shinichi; Yamamoto, Tadatoshi; Wadachi, Yoshiki

1983-01-01

The influence of interstitial water velocity on the migration of Sr-85 and Cs-137 in an aerated sandy soil layer was studied at different feed water velocities and feed times. As well known, it was found that Sr-85 migrated with interstitial water, but Cs-137 little migrated with interstitial water. The apparent migration velocity for each fraction corresponding to three concentrations (2 x 10 -2 , 1 x 10 -2 and 5 x 10 -3 μCi/g) of Sr-85 was further investigated. At constant interstitial water velocity (1cm/ min), different values were given for the apparent migration velocity of three fractions, and the fraction with thin concentration migrated faster. At constant feeding time (100hr), there was a linear relationship between apparent migration velocity of three fractions and interstitial water velocity, in the range of slow water velocity ( -2 and 5 x 10 -3 μCi/g) and interstitial water velocity, in the range of fast water velocity (> 1cm/min). (author)

Modernism and tradition and the traditions of modernism

Directory of Open Access Journals (Sweden)

Kros Džonatan

2006-01-01

Full Text Available Conventionally, the story of musical modernism has been told in terms of a catastrophic break with the (tonal past and the search for entirely new techniques and modes of expression suitable to a new age. The resulting notion of a single, linear, modernist mainstream (predicated on the basis of a Schoenbergian model of musical progress has served to conceal a more subtle relationship between past and present. Increasingly, it is being recognized that there exist many modernisms and their various identities are forged from a continual renegotiation between past and present, between tradition(s and the avant-garde. This is especially relevant when attempting to discuss the reception of modernism outside central Europe, where the adoption of (Germanic avant-garde attitudes was often interpreted as being "unpatriotic". The case of Great Britain is examined in detail: Harrison Birtwistle’s opera The Mask of Orpheus (1973–83 forms the focus for a wider discussion of modernism within the context of late/post-modern thought.

The effects of electron transfer on the energy loss of slow He2+, C2+, and C4+ ions penetrating a graphene fragment

International Nuclear Information System (INIS)

Mao, Fei; Zhang, Chao; Gao, Cong-Zhang; Dai, Jinxia; Zhang, Feng-Shou

2014-01-01

Electronic energy loss in the collision processes of slow ions with a graphene fragment is investigated by combining ab initio time-dependent density functional theory calculations for electrons with molecular dynamics simulations for ions in real time and real space. We study the electronic energy loss of slow He 2+ , C 2+ , and C 4+ ions penetrating the graphene fragment as a function of the ion velocity, and establish the velocity-proportional energy loss for low-charged ions down to 0.1 a.u. One mechanism clarified in the simulations for electron transfer is polarization capture, which is effective for bare ions at low velocities. The other one is resonance capture, by which the incident ion can capture electrons from the graphene fragment to its electron affinity levels, which have the same, or nearly the same, energy as those of the electron donor levels. The results demonstrate that the nonlinear behavior of energy loss of C 4+ is attributed to the large number of electrons captured by this multi-charged ion during the collision. (paper)

Computing discharge using the index velocity method

Science.gov (United States)

Levesque, Victor A.; Oberg, Kevin A.

2012-01-01

Application of the index velocity method for computing continuous records of discharge has become increasingly common, especially since the introduction of low-cost acoustic Doppler velocity meters (ADVMs) in 1997. Presently (2011), the index velocity method is being used to compute discharge records for approximately 470 gaging stations operated and maintained by the U.S. Geological Survey. The purpose of this report is to document and describe techniques for computing discharge records using the index velocity method. Computing discharge using the index velocity method differs from the traditional stage-discharge method by separating velocity and area into two ratings—the index velocity rating and the stage-area rating. The outputs from each of these ratings, mean channel velocity (V) and cross-sectional area (A), are then multiplied together to compute a discharge. For the index velocity method, V is a function of such parameters as streamwise velocity, stage, cross-stream velocity, and velocity head, and A is a function of stage and cross-section shape. The index velocity method can be used at locations where stage-discharge methods are used, but it is especially appropriate when more than one specific discharge can be measured for a specific stage. After the ADVM is selected, installed, and configured, the stage-area rating and the index velocity rating must be developed. A standard cross section is identified and surveyed in order to develop the stage-area rating. The standard cross section should be surveyed every year for the first 3 years of operation and thereafter at a lesser frequency, depending on the susceptibility of the cross section to change. Periodic measurements of discharge are used to calibrate and validate the index rating for the range of conditions experienced at the gaging station. Data from discharge measurements, ADVMs, and stage sensors are compiled for index-rating analysis. Index ratings are developed by means of regression

Very low velocity ion slowing down in binary ionic mixtures: Charge- and mass-asymmetry effects

Directory of Open Access Journals (Sweden)

Patrice Fromy

2010-10-01

Full Text Available A binary ionic mixture (BIM in dense and hot plasmas of specific concern for inertial confinement fusion and white dwarf crust is considered as a target for incoming light ions with a velocity smaller than the thermal electron one. The given target stopping power, mostly BIM monitored, is specifically studied in terms of charge and mass asymmetry in its ionic component. The classical plasma target is worked out within a dielectric framework, and scanned with respect to density, temperature, and BIM composition.

A fast-slow logic system

International Nuclear Information System (INIS)

Kawashima, Hideo.

1977-01-01

A fast-slow logic system has been made for use in multi-detector experiments in nuclear physics such as particle-gamma and particle-particle coincidence experiments. The system consists of a fast logic system and a slow logic system. The fast logic system has a function of fast coincidences and provides timing signals for the slow logic system. The slow logic system has a function of slow coincidences and a routing control of input analog signals to the ADCs. (auth.)

Subtle paranodal injury slows impulse conduction in a mathematical model of myelinated axons.

Directory of Open Access Journals (Sweden)

Charles F Babbs

Full Text Available This study explores in detail the functional consequences of subtle retraction and detachment of myelin around the nodes of Ranvier following mild-to-moderate crush or stretch mediated injury. An equivalent electrical circuit model for a series of equally spaced nodes of Ranvier was created incorporating extracellular and axonal resistances, paranodal resistances, nodal capacitances, time varying sodium and potassium currents, and realistic resting and threshold membrane potentials in a myelinated axon segment of 21 successive nodes. Differential equations describing membrane potentials at each nodal region were solved numerically. Subtle injury was simulated by increasing the width of exposed nodal membrane in nodes 8 through 20 of the model. Such injury diminishes action potential amplitude and slows conduction velocity from 19.1 m/sec in the normal region to 7.8 m/sec in the crushed region. Detachment of paranodal myelin, exposing juxtaparanodal potassium channels, decreases conduction velocity further to 6.6 m/sec, an effect that is partially reversible with potassium ion channel blockade. Conduction velocity decreases as node width increases or as paranodal resistance falls. The calculated changes in conduction velocity with subtle paranodal injury agree with experimental observations. Nodes of Ranvier are highly effective but somewhat fragile devices for increasing nerve conduction velocity and decreasing reaction time in vertebrate animals. Their fundamental design limitation is that even small mechanical retractions of myelin from very narrow nodes or slight loosening of paranodal myelin, which are difficult to notice at the light microscopic level of observation, can cause large changes in myelinated nerve conduction velocity.

Transient crustal movement in the northern Izu-Bonin arc starting in 2004: A large slow slip event or a slow back-arc rifting event?

Science.gov (United States)

Arisa, Deasy; Heki, Kosuke

2016-07-01

The Izu-Bonin arc lies along the convergent boundary where the Pacific Plate subducts beneath the Philippine Sea Plate. Horizontal velocities of continuous Global Navigation Satellite System stations on the Izu Islands move eastward by up to 1 cm/year relative to the stable part of the Philippine Sea Plate suggesting active back-arc rifting behind the northern part of the arc. Here, we report that such eastward movements transiently accelerated in the middle of 2004 resulting in 3 cm extra movements in 3 years. We compare three different mechanisms possibly responsible for this transient movement, i.e. (1) postseismic movement of the 2004 September earthquake sequence off the Kii Peninsula far to the west, (2) a temporary activation of the back-arc rifting to the west dynamically triggered by seismic waves from a nearby earthquake, and (3) a large slow slip event in the Izu-Bonin Trench to the east. By comparing crustal movements in different regions, the first possibility can be shown unlikely. It is difficult to rule out the second possibility, but current evidence support the third possibility, i.e. a large slow slip event with moment magnitude of 7.5 may have occurred there.

Experimental research on time-resolved evolution of cathode plasma expansion velocity in a long pulsed magnetically insulated coaxial diode

Science.gov (United States)

Zhu, Danni; Zhang, Jun; Zhong, Huihuang; Ge, Xingjun; Gao, Jingming

2018-02-01

Unlike planar diodes, separate research of the axial and radial plasma expansion velocities is difficult for magnetically insulated coaxial diodes. Time-resolved electrical diagnostic which is based on the voltage-ampere characteristics has been employed to study the temporal evolution of the axial and radial cathode plasma expansion velocities in a long pulsed magnetically insulated coaxial diode. Different from a planar diode with a "U" shaped profile of temporal velocity evolution, the temporal evolution trend of the axial expansion velocity is proved to be a "V" shaped profile. Apart from the suppression on the radial expansion velocity, the strong magnetic field is also conducive to slowing down the axial expansion velocity. Compared with the ordinary graphite cathode, the carbon velvet and graphite composite cathode showed superior characteristics as judged by the low plasma expansion velocity and long-term electrical stability as a promising result for applications where long-pulsed and reliable operation at high power is required.

Very slow neutrons

International Nuclear Information System (INIS)

Frank, A.

1983-01-01

The history is briefly presented of the research so far of very slow neutrons and their basic properties are explained. The methods are described of obtaining very slow neutrons and the problems of their preservation are discussed. The existence of very slow neutrons makes it possible to perform experiments which may deepen the knowledge of the fundamental properties of neutrons. Their wavelength approximates that of visible radiation. The possibilities and use are discussed of neutron optical systems (neutron microscope) which could be an effective instrument for the study of the detailed arrangement, especially of organic substances. (B.S.)

The unappreciated slowness of conventional tourism

Directory of Open Access Journals (Sweden)

G.R. Larsen

2016-05-01

Full Text Available Most tourists are not consciously engaging in ‘slow travel’, but a number of travel behaviours displayed by conventional tourists can be interpreted as slow travel behaviour. Based on Danish tourists’ engagement with the distances they travel across to reach their holiday destination, this paper explores unintended slow travel behaviours displayed by these tourists. None of the tourists participating in this research were consciously doing ‘slow travel’, and yet some of their most valued holiday memories are linked to slow travel behaviours. Based on the analysis of these unintended slow travel behaviours, this paper will discuss the potential this insight might hold for promotion of slow travel. If unappreciated and unintentional slow travel behaviours could be utilised in the deliberate effort of encouraging more people to travel slow, ‘slow travel’ will be in a better position to become integrated into conventional travel behaviour.

Does Scottish Education Need Traditions?

Science.gov (United States)

Paterson, Lindsay

2009-01-01

Scottish education was, until quite recently, the conscious product of liberal tradition, of the belief by influential elites that the nation's educational history was strong, coherent, and progressive, a source of economic flexibility, of modernising ideas, and of liberal opportunity. In recent decades, however, it has become fashionable to decry…

Stress wave velocity patterns in the longitudinal-radial plane of trees for defect diagnosis

Science.gov (United States)

Guanghui Li; Xiang Weng; Xiaocheng Du; Xiping Wang; Hailin Feng

2016-01-01

Acoustic tomography for urban tree inspection typically uses stress wave data to reconstruct tomographic images for the trunk cross section using interpolation algorithm. This traditional technique does not take into account the stress wave velocity patterns along tree height. In this study, we proposed an analytical model for the wave velocity in the longitudinal–...

Lectures on ion-atom collisions from nonrelativistic to relativistic velocities

CERN Document Server

Eichler, Jörg

2005-01-01

Atomic collisions offer some unique opportunities to study atomic structure and reaction mechanisms in experiment and theory, especially for projectiles of high atomic number provided by modern accelerators. The book is meant as an introduction into the field and provides some basic theoretical understanding of the atomic processes occurring when a projectile hits another atom. It also furnishes the tools for a mathematical description, however, without going deeper into the technical details, which can be found in the literature given. With this aim, the focus is on reactions, in which only a single active electron participates. Collisional excitation, ionization and charge transfer are discussed for collision velocities ranging from slow to comparable to thespeed of light. For the highest projectile velocities, energy can be converted into mass, so that electron-positron pairs are created. In addition to the systematic treatment, a theoretical section specializes on electron-electroncorrelations and three...

Evaluating methods to quantify spatial variation in the velocity of biological invasions

Science.gov (United States)

Clement Tisseuil; Aiko Gryspeirt; Renaud Lancelot; Maryline Pioz; Andrew Liebhold; Marius. Gilbert

2016-01-01

Invading species rarely spread homogeneously through a landscape and invasion patterns typically display irregular frontal boundaries as the invasion progresses through space. Those irregular patterns are generally produced by local environmental factors that may slow or accelerate movement of the frontal boundary. While there is an abundant literature on species...

Stationary velocity distributions in traffic flows

International Nuclear Information System (INIS)

1997-01-01

We introduce a traffic flow model that incorporates clustering and passing. We obtain analytically the steady state characteristics of the flow from a Boltzmann-like equation. A single dimensionless parameter, R=c 0 v 0 t 0 with c 0 the concentration, v 0 the velocity range, and t 0 -1 the passing rate, determines the nature of the steady state. When R 1, large clusters with average mass left-angle m right-angle ∼R α form, and the flux is J∼R -γ . The initial distribution of slow cars governs the statistics. When P 0 (v)∼v μ as v→0, the scaling exponents are γ=1/(μ+2), α=1/2 when μ>0, and α=(μ+1)/(μ+2) when μ<0. copyright 1997 The American Physical Society

Kinematics and statistics of dense, slow granular flow through vertical channels

Science.gov (United States)

Ananda, K. S.; Moka, Sudheshna; Nott, Prabhu R.

We have investigated the flow of dry granular materials through vertical channels in the regime of dense slow flow using video imaging of the particles adjacent to a transparent wall. Using an image processing technique based on particle tracking velocimetry, the video movies were analysed to obtain the velocities of individual particles. Experiments were conducted in two- and three-dimensional channels. In the latter, glass beads and mustard seeds were used as model granular materials, and their translational velocities were measured. In the former, aluminium disks with a dark diametral stripe were used and their translational velocities and spin were measured. Experiments in the three-dimensional channels were conducted for a range of the channel width W, and for smooth and rough sidewalls. As in earlier studies, we find that shearing takes place predominantly in thin layers adjacent to the walls, while the rest of the material appears to move as a plug. However, there are large velocity fluctuations even in the plug, where the macroscopic deformation rate is negligibly small. The thickness of the shear layer, scaled by the particle diameter dp, increases weakly with W/dp. The experimental data for the velocity field are in good agreement with the Cosserat plasticity model proposed recently. We also measured the mean spin of the particles in the two-dimensional channel, and its deviation from half the vorticity. There is a clear, measurable deviation, which too is in qualitative agreement with the Cosserat plasticity model. The statistics of particle velocity and spin fluctuations in the two-dimensional channel were analysed by determining their probability distribution function, and their spatial and temporal correlation. They were all found to be broadly similar to previous observations for three-dimensional channels, but some differences are evident. The spatial correlation of the velocity fluctuations are much stronger in the two-dimensional channel, implying

Velocity dependence of vestibular information for postural control on tilting surfaces

Science.gov (United States)

Kluzik, JoAnn; Hlavacka, Frantisek

2016-01-01

Vestibular information is known to be important for postural stability on tilting surfaces, but the relative importance of vestibular information across a wide range of surface tilt velocities is less clear. We compared how tilt velocity influences postural orientation and stability in nine subjects with bilateral vestibular loss and nine age-matched, control subjects. Subjects stood on a force platform that tilted 6 deg, toes-up at eight velocities (0.25 to 32 deg/s), with and without vision. Results showed that visual information effectively compensated for lack of vestibular information at all tilt velocities. However, with eyes closed, subjects with vestibular loss were most unstable within a critical tilt velocity range of 2 to 8 deg/s. Subjects with vestibular deficiency lost their balance in more than 90% of trials during the 4 deg/s condition, but never fell during slower tilts (0.25–1 deg/s) and fell only very rarely during faster tilts (16–32 deg/s). At the critical velocity range in which falls occurred, the body center of mass stayed aligned with respect to the surface, onset of ankle dorsiflexion was delayed, and there was delayed or absent gastrocnemius inhibition, suggesting that subjects were attempting to actively align their upper bodies with respect to the moving surface instead of to gravity. Vestibular information may be critical for stability at velocities of 2 to 8 deg/s because postural sway above 2 deg/s may be too fast to elicit stabilizing responses through the graviceptive somatosensory system, and postural sway below 8 deg/s may be too slow for somatosensory-triggered responses or passive stabilization from trunk inertia. PMID:27486101

Movement - uncontrolled or slow

Science.gov (United States)

Dystonia; Involuntary slow and twisting movements; Choreoathetosis; Leg and arm movements - uncontrollable; Arm and leg movements - uncontrollable; Slow involuntary movements of large muscle groups; Athetoid movements

Large exchange-dominated domain wall velocities in antiferromagnetically coupled nanowires

Science.gov (United States)

Kuteifan, Majd; Lubarda, M. V.; Fu, S.; Chang, R.; Escobar, M. A.; Mangin, S.; Fullerton, E. E.; Lomakin, V.

2016-04-01

Magnetic nanowires supporting field- and current-driven domain wall motion are envisioned for methods of information storage and processing. A major obstacle for their practical use is the domain-wall velocity, which is traditionally limited for low fields and currents due to the Walker breakdown occurring when the driving component reaches a critical threshold value. We show through numerical and analytical modeling that the Walker breakdown limit can be extended or completely eliminated in antiferromagnetically coupled magnetic nanowires. These coupled nanowires allow for large domain-wall velocities driven by field and/or current as compared to conventional nanowires.

KEK-IMSS Slow Positron Facility

Energy Technology Data Exchange (ETDEWEB)

Hyodo, T; Wada, K; Yagishita, A; Kosuge, T; Saito, Y; Kurihara, T; Kikuchi, T; Shirakawa, A; Sanami, T; Ikeda, M; Ohsawa, S; Kakihara, K; Shidara, T, E-mail: toshio.hyodo@kek.jp [High Energy Accelerator Research Organization (KEK) 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan)

2011-12-01

The Slow Positron Facility at the Institute of Material Structure Science (IMSS) of High Energy Accelerator Research Organization (KEK) is a user dedicated facility with an energy tunable (0.1 - 35 keV) slow positron beam produced by a dedicated 55MeV linac. The present beam line branches have been used for the positronium time-of-flight (Ps-TOF) measurements, the transmission positron microscope (TPM) and the photo-detachment of Ps negative ions (Ps{sup -}). During the year 2010, a reflection high-energy positron diffraction (RHEPD) measurement station is going to be installed. The slow positron generator (converter/ moderator) system will be modified to get a higher slow positron intensity, and a new user-friendly beam line power-supply control and vacuum monitoring system is being developed. Another plan for this year is the transfer of a {sup 22}Na-based slow positron beam from RIKEN. This machine will be used for the continuous slow positron beam applications and for the orientation training of those who are interested in beginning researches with a slow positron beam.

Slow photoelectron imaging spectroscopy of CCO- and CCS-.

Science.gov (United States)

Garand, Etienne; Yacovitch, Tara I; Neumark, Daniel M

2008-08-21

High-resolution photodetachment spectra of CCO(-) and CCS(-) using slow photoelectron velocity-map imaging spectroscopy are reported. Well-resolved transitions to the neutral X (3)Sigma(-), a (1)Delta, b (1)Sigma(+), and A (3)Pi states are seen for both species. The electron affinities of CCO and CCS are determined to be 2.3107+/-0.0006 and 2.7475+/-0.0006 eV, respectively, and precise term energies for the a (1)Delta, b (1)Sigma(+), and A (3)Pi excited states are also determined. The two low-lying singlet states of CCS are observed for the first time, as are several vibronic transitions within the four bands. Analysis of hot bands finds the spin-orbit orbit splitting in the X (2)Pi ground state of CCO(-) and CCS(-) to be 61 and 195 cm(-1), respectively.

Too slow, for Milton

OpenAIRE

Armstrong, N.

2011-01-01

Too slow, for Milton was written in 2011, as part of a memorial project for Milton Babbitt. The piece borrows harmonies from Babbitt's Composition for 12 Instruments (harmonies which Babbitt had in turn borrowed from Schoenberg's Ode to Napoleon), but unfolds them as part of a musical texture characterised by repetition, resonance, and a slow rate of change. As Babbitt once told me that my music was 'too slow', this seemed an appropriately obstinate form of homage.

Treating gynaecological disorders with traditional Chinese medicine ...

African Journals Online (AJOL)

Traditional Chinese Medicine (TCM) has significant advantages in treating gynaecological disorders. The paper has provided a brief introduction on the current progress of treating some gynaecological disorders including endometriosis, infertility, dysmenorrhea, abnormal uterine bleeding, premenstrual syndrome, ...

The importance of high injection velocity to reduce plasma armature growth and drag in hypervelocity railguns

International Nuclear Information System (INIS)

Hawke, R.S.; Dixon, W.R.; Kang, S.W.; McCallen, R.C.; Susoeff, A.R.; Asay, J.R.; Shaninpoor, M.

1987-01-01

Plasmas are required to serve as armature in hypervelocity railguns. Typically, the plasmas are at temperatures of about 20-30,000 K and result in a high heat flux on the barrel wall. Slow moving plasmas radiate heat and melt the launcher wall causing it to ablate and resulting in a growth of the armature mass and length. As the velocity increases, the more massive and longer armature will result in greater viscous drag and ultimately limit the maximum achievable velocity. Several possible means of reducing the armature growth are possible. This paper discusses two of them, use of heat resistant barrel materials, and reduction of wall heating by reduction of exposure time through use of a high initial velocity. A summary of experimentally based, material ablation resistance calculations is presented. Second, the benefit of high injection velocity is evaluated. Finally, a joint SNLA and LLNL railgun research project based on the above considerations are described

Cryopreservation of human oocytes, zygotes, embryos and blastocysts: A comparison study between slow freezing and ultra rapid (vitrification methods

Directory of Open Access Journals (Sweden)

Tahani Al-Azawi

2013-12-01

Full Text Available Preservation of female genetics is currently done primarily by means of oocyte and embryo cryopreservation. The field has seen much progress during its four-decade history, progress driven predominantly by research in humans. It can also be done by preservation of ovarian tissue or entire ovary for transplantation, followed by oocyte harvesting or natural fertilization. Two basic cryopreservation techniques rule the field, slow-rate freezing, the first to be developed and vitrification which in recent years, has gained a foothold. The slow-rate freezing method previously reported had low survival and pregnancy rates, along with the high cost of cryopreservation. Although there are some recent data indicating better survival rates, cryopreservation by the slow freezing method has started to discontinue. Vitrification of human embryos, especially at early stages, became a more popular alternative to the slow rate freezing method due to reported comparable clinical and laboratory outcomes. In addition, vitrification is relatively simple, requires no expensive programmable freezing equipment, and uses a small amount of liquid nitrogen for freezing. Moreover, oocyte cryopreservation using vitrification has been proposed as a solution to maintain women’s fertility by serving and freezing their oocytes at the optimal time. The aim of this research is to compare slow freezing and vitrification in cryopreservation of oocytes, zygotes, embryos and blastocysts during the last twelve years. Therefore, due to a lot of controversies in this regard, we tried to achieve an exact idea about the subject and the best technique used.

Heart rate effects of intraosseous injections using slow and fast rates of anesthetic solution deposition.

Science.gov (United States)

Susi, Louis; Reader, Al; Nusstein, John; Beck, Mike; Weaver, Joel; Drum, Melissa

2008-01-01

The authors, using a crossover design, randomly administered, in a single-blind manner, 3 primary intraosseous injections to 61 subjects using: the Wand local anesthetic system at a deposition rate of 45 seconds (fast injection); the Wand local anesthetic system at a deposition rate of 4 minutes and 45 seconds (slow injection); a conventional syringe injection at a deposition rate of 4 minutes and 45 seconds (slow injection), in 3 separate appointments spaced at least 3 weeks apart. A pulse oximeter measured heart rate (pulse). The results demonstrated the mean maximum heart rate was statistically higher with the fast intraosseous injection (average 21 to 28 beats/min increase) than either of the 2 slow intraosseous injections (average 10 to 12 beats/min increase). There was no statistically significant difference between the 2 slow injections. We concluded that an intraosseous injection of 1.4 mL of 2% lidocaine with 1 : 100,000 epinephrine with the Wand at a 45-second rate of anesthetic deposition resulted in a significantly higher heart rate when compared with a 4-minute and 45-second anesthetic solution deposition using either the Wand or traditional syringe.

Acoustic slow waves and the consolidation transition

International Nuclear Information System (INIS)

Johnson, D.L.; Plona, T.J.

1982-01-01

We have investigated the ultrasonic properties of unconsolidated (loose) glass beads and of lightly fused (consolidated) glass beads when the pore space is saturated with water. At a frequency of 500 kHz we have observed a single compressional wave in the former whose speed is 1.79 km/s and two distinct compressional waves with speeds 2.81 km/s and 0.96 km/s in the latter. The Biot theory is shown to give an accurate description of this phenomenon. We also analyze the acoustics of low temperature He ii in packed powder superleaks; either the fast wave for unconsolidated systems or the slow wave in a highly consolidated (fused) frame may be considered to be the 4th sound mode. In all such systems, the acoustic properties can be very simply understood by considering the velocities of propagation as continuous functions of the elastic moduli of the solid skeletal frames

Different maturational changes of fast and slow sleep spindles in the first four years of life.

Science.gov (United States)

D'Atri, Aurora; Novelli, Luana; Ferrara, Michele; Bruni, Oliviero; De Gennaro, Luigi

2018-02-01

Massive changes in brain morphology and function in the first years of life reveal a postero-anterior trajectory of cortical maturation accompanied by regional modifications of NREM sleep. One of the most sensible marker of this maturation process is represented by electroencephalographic (EEG) activity within the frequency range of sleep spindles. However, direct evidence that these changes actually reflect maturational modifications of fast and slow spindles still lacks. Our study aimed at answering the following questions: 1. Do cortical changes at 11.50 Hz frequency correspond to slow spindles? 2. Do fast and slow spindles show different age trajectories and different topographical distributions? 3. Do changes in peak frequency explain age changes of slow and fast spindles? We measured the antero-posterior changes of slow and fast spindles in the first 60 min of nightly sleep of 39 infants and children (0-48 mo.). We found that (A) changes of slow spindles from birth to childhood mostly affect frontal areas (B) variations of fast and slow spindles across age groups go in opposite direction, the latter progressively increasing across ages; (C) this process is not merely reducible to changes of spindle frequency. As a main finding, our cross-sectional study shows that the first form of mature spindle (i.e., corresponding to the adult phasic event of NREM sleep) is marked by the emergence of slow spindles on anterior regions around the age of 12 months. Copyright © 2017 Elsevier B.V. All rights reserved.

The properties of fast and slow oblique solitons in a magnetized plasma

Science.gov (United States)

McKenzie, J. F.; Doyle, T. B.

2002-01-01

This work builds on a recent treatment by McKenzie and Doyle [Phys. Plasmas 8, 4367 (2001)], on oblique solitons in a cold magnetized plasma, to include the effects of plasma thermal pressure. Conservation of total momentum in the direction of wave propagation immediately shows that if the flow is supersonic, compressive (rarefactive) changes in the magnetic pressure induce decelerations (accelerations) in the flow speed, whereas if the flow is subsonic, compressive (rarefactive) changes in the magnetic pressure induce accelerations (decelerations) in the flow speed. Such behavior is characteristic of a Bernoulli-type plasma momentum flux which exhibits a minimum at the plasma sonic point. The plasma energy flux (kinetic plus enthalpy) also shows similar Bernoulli-type behavior. This transonic effect is manifest in the spatial structure equation for the flow speed (in the direction of propagation) which shows that soliton structures may exist if the wave speed lies either (i) in the range between the fast and Alfven speeds or (ii) between the sound and slow mode speed. These conditions follow from the requirement that a defined, characteristic "soliton parameter" m exceeds unity. It is in this latter slow soliton regime that the effects of plasma pressure are most keenly felt. The equilibrium points of the structure equation define the center of the wave. The structure of both fast and slow solitons is elucidated through the properties of the energy integral function of the structure equation. In particular, the slow soliton, which owes its existence to plasma pressure, may have either a compressive or rarefactive nature, and exhibits a rich structure, which is revealed through the spatial structure of the longitudinal speed and its corresponding transverse velocity hodograph.

The properties of fast and slow oblique solitons in a magnetized plasma

International Nuclear Information System (INIS)

McKenzie, J.F.; Doyle, T.B.

2002-01-01

This work builds on a recent treatment by McKenzie and Doyle [Phys. Plasmas 8, 4367 (2001)], on oblique solitons in a cold magnetized plasma, to include the effects of plasma thermal pressure. Conservation of total momentum in the direction of wave propagation immediately shows that if the flow is supersonic, compressive (rarefactive) changes in the magnetic pressure induce decelerations (accelerations) in the flow speed, whereas if the flow is subsonic, compressive (rarefactive) changes in the magnetic pressure induce accelerations (decelerations) in the flow speed. Such behavior is characteristic of a Bernoulli-type plasma momentum flux which exhibits a minimum at the plasma sonic point. The plasma energy flux (kinetic plus enthalpy) also shows similar Bernoulli-type behavior. This transonic effect is manifest in the spatial structure equation for the flow speed (in the direction of propagation) which shows that soliton structures may exist if the wave speed lies either (i) in the range between the fast and Alfven speeds or (ii) between the sound and slow mode speed. These conditions follow from the requirement that a defined, characteristic 'soliton parameter' m exceeds unity. It is in this latter slow soliton regime that the effects of plasma pressure are most keenly felt. The equilibrium points of the structure equation define the center of the wave. The structure of both fast and slow solitons is elucidated through the properties of the energy integral function of the structure equation. In particular, the slow soliton, which owes its existence to plasma pressure, may have either a compressive or rarefactive nature, and exhibits a rich structure, which is revealed through the spatial structure of the longitudinal speed and its corresponding transverse velocity hodograph

Political determinants of progress in the MDGs in Sub-Saharan Africa

DEFF Research Database (Denmark)

Atti, Emma; Gulis, Gabriel

2017-01-01

suggest a significant main effect of eco-political and geo-political groups on some of the health variables. Political conflict as measured by FSI and political participation as measured by CLS were stronger predictors of slow progress in reducing under-five mortality rates and maternal mortality ratios......Sub-Saharan Africa (SSA) lagged furthest behind in achieving targets for the millennium development goals (MDG). We investigate the hypothesis that its slow progress is influenced by political factors. Longitudinal data on three health MDG indicators: under-five mortality, maternal mortality....... Our findings highlight the need for further research on political determinants of mortality in SSA. Cohesive effort should focus on strengthening countries' political, economic and social capacities in order to achieve sustainable goals beyond 2015....

Initial Progress Rates as Related to Performance in a Personalized System of Instruction

Science.gov (United States)

Henneberry, John K.

1976-01-01

Discusses research which explored the hypothesis that students who are fast starters in a personalized system of instruction psychology course would perform better and maintain faster course progress rates than slow starters. Findings indicate that students' starting pace is predictive of course performance and subsequent progress rates.…

Superconducting accelerating structures for very low velocity ion beams

Directory of Open Access Journals (Sweden)

J. Xu

2008-03-01

Full Text Available This paper presents designs for four types of very-low-velocity superconducting (SC accelerating cavity capable of providing several MV of accelerating potential per cavity, and suitable for particle velocities in the range 0.006velocity profile to maximize the output energy for each of a number of different ion species. Several laboratories in the U.S. and Europe are planning exotic beam facilities based on SC linacs. The cavity designs presented here are intended for the front end of such linacs, particularly for the postacceleration of rare isotopes of low charge state. Several types of SC cavities have been developed recently to cover particle velocities above 0.06c. Superconducting four-gap quarter-wave resonators for velocities 0.008<β=v/c<0.05 were developed about two decades ago and have been successfully operated at the ATLAS SC linac at Argonne National Laboratory. Since that time, progress in simulation tools, cavity fabrication, and processing have increased SC cavity gradients by a factor of 3–4. This paper applies these tools to optimize the design of a four-gap quarter-wave resonator for exotic beam facilities and other low-velocity applications.

Superconducting accelerating structures for very low velocity ion beams

Energy Technology Data Exchange (ETDEWEB)

Xu, J.; Shepard, K.W.; Ostroumov, P.N.; Fuerst, J.D.; Waldschmidt, G.; /Argonne; Gonin, I.V.; /Fermilab

2008-01-01

This paper presents designs for four types of very-low-velocity superconducting accelerating cavity capable of providing several MV of accelerating potential per cavity, and suitable for particle velocities in the range 0.006 < v/c < 0.06. Superconducting TEM-class cavities have been widely applied to CW acceleration of ion beams. SC linacs can be formed as an array of independently-phased cavities, enabling a variable velocity profile to maximize the output energy for each of a number of different ion species. Several laboratories in the US and Europe are planning exotic beam facilities based on SC linacs. The cavity designs presented here are intended for the front-end of such linacs, particularly for the post-acceleration of rare isotopes of low charge state. Several types of SC cavities have been developed recently to cover particle velocities above 0.06c. Superconducting four-gap quarter-wave resonators for velocities 0.008 < {beta} = v/c < 0.05 were developed about two decades ago and have been successfully operated at the ATLAS SC linac at Argonne National Laboratory. Since that time, progress in simulation tools, cavity fabrication and processing have increased SC cavity gradients by a factor of 3-4. This paper applies these tools to optimize the design of a four-gap quarter-wave resonator for exotic beam facilities and other low-velocity applications.

Loading intensity prediction by velocity and the OMNI-RES 0–10 scale in bench press

OpenAIRE

Naclerio, Fernando; Larumbe-Zabala, Eneko

2017-01-01

This study examined the possibility of using movement velocity and the perceived exertion as indicators of relative load in the bench press exercise. Three hundred eight young, healthy, resistance trained athletes (242 male and 66 female) performed a progressive strength test up to the one-repetition maximum for the individual determination of the full load-velocity and load-exertion relationships. Longitudinal regression models were used to predict the relative load from the average velocity...

Millennial-scale temperature change velocity in the continental northern Neotropics.

Directory of Open Access Journals (Sweden)

Alexander Correa-Metrio

Full Text Available Climate has been inherently linked to global diversity patterns, and yet no empirical data are available to put modern climate change into a millennial-scale context. High tropical species diversity has been linked to slow rates of climate change during the Quaternary, an assumption that lacks an empirical foundation. Thus, there is the need for quantifying the velocity at which the bioclimatic space changed during the Quaternary in the tropics. Here we present rates of climate change for the late Pleistocene and Holocene from Mexico and Guatemala. An extensive modern pollen survey and fossil pollen data from two long sedimentary records (30,000 and 86,000 years for highlands and lowlands, respectively were used to estimate past temperatures. Derived temperature profiles show a parallel long-term trend and a similar cooling during the Last Glacial Maximum in the Guatemalan lowlands and the Mexican highlands. Temperature estimates and digital elevation models were used to calculate the velocity of isotherm displacement (temperature change velocity for the time period contained in each record. Our analyses showed that temperature change velocities in Mesoamerica during the late Quaternary were at least four times slower than values reported for the last 50 years, but also at least twice as fast as those obtained from recent models. Our data demonstrate that, given extremely high temperature change velocities, species survival must have relied on either microrefugial populations or persistence of suppressed individuals. Contrary to the usual expectation of stable climates being associated with high diversity, our results suggest that Quaternary tropical diversity was probably maintained by centennial-scale oscillatory climatic variability that forestalled competitive exclusion. As humans have simplified modern landscapes, thereby removing potential microrefugia, and climate change is occurring monotonically at a very high velocity, extinction risk

Millennial-scale temperature change velocity in the continental northern Neotropics.

Science.gov (United States)

Correa-Metrio, Alexander; Bush, Mark; Lozano-García, Socorro; Sosa-Nájera, Susana

2013-01-01

Climate has been inherently linked to global diversity patterns, and yet no empirical data are available to put modern climate change into a millennial-scale context. High tropical species diversity has been linked to slow rates of climate change during the Quaternary, an assumption that lacks an empirical foundation. Thus, there is the need for quantifying the velocity at which the bioclimatic space changed during the Quaternary in the tropics. Here we present rates of climate change for the late Pleistocene and Holocene from Mexico and Guatemala. An extensive modern pollen survey and fossil pollen data from two long sedimentary records (30,000 and 86,000 years for highlands and lowlands, respectively) were used to estimate past temperatures. Derived temperature profiles show a parallel long-term trend and a similar cooling during the Last Glacial Maximum in the Guatemalan lowlands and the Mexican highlands. Temperature estimates and digital elevation models were used to calculate the velocity of isotherm displacement (temperature change velocity) for the time period contained in each record. Our analyses showed that temperature change velocities in Mesoamerica during the late Quaternary were at least four times slower than values reported for the last 50 years, but also at least twice as fast as those obtained from recent models. Our data demonstrate that, given extremely high temperature change velocities, species survival must have relied on either microrefugial populations or persistence of suppressed individuals. Contrary to the usual expectation of stable climates being associated with high diversity, our results suggest that Quaternary tropical diversity was probably maintained by centennial-scale oscillatory climatic variability that forestalled competitive exclusion. As humans have simplified modern landscapes, thereby removing potential microrefugia, and climate change is occurring monotonically at a very high velocity, extinction risk for tropical

Neuroprotection in Experimental Autoimmune Encephalomyelitis and Progressive Multiple Sclerosis by Cannabis-Based Cannabinoids.

Science.gov (United States)

Pryce, Gareth; Riddall, Dieter R; Selwood, David L; Giovannoni, Gavin; Baker, David

2015-06-01

Multiple sclerosis (MS) is the major immune-mediated, demyelinating, neurodegenerative disease of the central nervous system. Compounds within cannabis, notably Δ9-tetrahydrocannabinol (Δ9-THC) can limit the inappropriate neurotransmissions that cause MS-related problems and medicinal cannabis is now licenced for the treatment of MS symptoms. However, the biology indicates that the endocannabinoid system may offer the potential to control other aspects of disease. Although there is limited evidence that the cannabinoids from cannabis are having significant immunosuppressive activities that will influence relapsing autoimmunity, we and others can experimentally demonstrate that they may limit neurodegeneration that drives progressive disability. Here we show that synthetic cannabidiol can slow down the accumulation of disability from the inflammatory penumbra during relapsing experimental autoimmune encephalomyelitis (EAE) in ABH mice, possibly via blockade of voltage-gated sodium channels. In addition, whilst non-sedating doses of Δ9-THC do not inhibit relapsing autoimmunity, they dose-dependently inhibit the accumulation of disability during EAE. They also appear to slow down clinical progression during MS in humans. Although a 3 year, phase III clinical trial did not detect a beneficial effect of oral Δ9-THC in progressive MS, a planned subgroup analysis of people with less disability who progressed more rapidly, demonstrated a significant slowing of progression by oral Δ9-THC compared to placebo. Whilst this may support the experimental and biological evidence for a neuroprotective effect by the endocannabinoid system in MS, it remains to be established whether this will be formally demonstrated in further trials of Δ9-THC/cannabis in progressive MS.

Slow Tourism: Exploring the discourses

Directory of Open Access Journals (Sweden)

J. Guiver

2016-05-01

Full Text Available ‘Slow travel’ and ‘slow tourism’ are relatively new, but contested, concepts. This paper examines the meanings ascribed to them in the academic literature and websites targeted at potential tourists. It finds concurrence on aspects of savouring time at the destination and investing time to appreciate the locality, its people, history, culture and products, but detects different emphases. The academic literature stresses the benefits to the destination and global sustainability, while the websites focus on the personal benefits and ways of becoming a ‘slow tourist’. Food and drink epitomise the immersion in and absorption of the destination and the multi-dimensional tourism experience, contrasted with the superficiality of mainstream tourism. The paper discusses whether tourists practising slow tourism without using the label are slow tourists or not.

Replacement of traditional seawater-soluble pigments by starch and hydrolytic enzymes in polishing antifouling coatings

DEFF Research Database (Denmark)

Olsen, Søren Martin; Pedersen, L. T.; Dam-Johansen, Kim

2010-01-01

The use of starch and hydrolytic enzymes as replacement for traditional polishing pigments (e.g., Cu2O and ZnO) in antifouling coatings has been investigated. The enzymes facilitate a slow conversion of water-insoluble starch into water-soluble glucose, and dissolution of glucose causes the devel......The use of starch and hydrolytic enzymes as replacement for traditional polishing pigments (e.g., Cu2O and ZnO) in antifouling coatings has been investigated. The enzymes facilitate a slow conversion of water-insoluble starch into water-soluble glucose, and dissolution of glucose causes...... the development of a leached (porous) layer in the wetted, outermost part of the coating. Subsequent water-binder interaction at the pore walls gives rise to polishing, in a manner similar to that of conventional antifouling coatings. Different starch types have been evaluated and classified as potential coating...

Do axes of rotation change during fast and slow motions of the dominant and non-dominate arms?

Directory of Open Access Journals (Sweden)

Pagano Christopher

2011-12-01

Full Text Available The velocity-dependent change in rotational axes observed in the control of unconstrained 3D arm rotations for the dominant limb seems to conform to a minimum inertia resistance (MIR principle [4]. This is an efficient biomechanical solution that allows for the reduction of torques. We tested whether the MIR principle governs rotating movement when subjects were instructed to maintain the shoulder-elbow joint axis close to horizontal for both dominant and non dominant limbs. Subjects (n=12 performed externalinternal rotations of their arms in two angular positions (90° versus 150°, two angular velocities (slow (S versus fast (F, and in two sensory conditions (kinaesthetic (K versus visuo- kinaesthetic (VK. We expected more scattered displacements of the rotation axis employed for rotating the non dominant limb compared to the dominant limb. The results showed that the rotational axis of a multiarticulated limb coincided with SH-EL at S & F velocity for both arms.

A joint inversion for shear velocity and anisotropy: the Woodlark Rift, Papua New Guinea

Science.gov (United States)

Eilon, Zachary; Abers, Geoffrey A.; Gaherty, James B.

2016-08-01

Trade-offs between velocity and anisotropy heterogeneity complicate the interpretation of differential traveltime data and have the potential to bias isotropic tomographic models. By constructing a simple parametrisation to describe an elastic tensor with hexagonal symmetry, we find analytic solutions to the Christoffel equations in terms of fast and slow horizontal velocities that allow us to simultaneously invert differential traveltime data and splitting data from teleseismic S arrivals to recover 3-D velocity and anisotropy structure. This technique provides a constraint on the depth-extent of shallow anisotropy, otherwise absent from interpretations based on SKS splitting alone. This approach is well suited to the young Woodlark Rift, where previous studies have found strong velocity variation and substantial SKS splitting in a continental rift with relatively simple geometry. This study images a low-velocity rift axis with ≤4 per cent spreading-parallel anisotropy at 50-100 km depth that separates regions of pre-existing lithospheric fabric, indicating the synchronous development of extensional crystallographic preferred orientation and lithospheric thinning. A high-velocity slab fragment north of the rift axis is associated with strike-parallel anisotropic fast axes, similar to that seen in the shallow mantle of some subduction zones. In addition to the insights provided by the anisotropy structure, the improvement in fit to the differential traveltime data demonstrates the merit to a joint inversion that accounts for anisotropy.

Slow-release fluoride devices for the control of dental decay.

Science.gov (United States)

Chong, Lee-Yee; Clarkson, Jan E; Dobbyn-Ross, Lorna; Bhakta, Smriti

2018-03-01

Slow-release fluoride devices have been investigated as a potentially cost-effective method of reducing dental caries in people with high risk of disease. This is the second update of the Cochrane Review first published in 2006 and previously updated in 2014. To evaluate the effectiveness and safety of different types of slow-release fluoride devices on preventing, arresting, or reversing the progression of carious lesions on all surface types of primary (deciduous) and permanent teeth. Cochrane Oral Health's Information Specialist searched the following electronic databases: Cochrane Oral Health's Trials Register (to 23 January 2018); the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 12) in the Cochrane Library (searched 23 January 2018); MEDLINE Ovid (1946 to 23 January 2018); and Embase Ovid (1980 to 23 January 2018). The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials (23 January 2018). We placed no restrictions on the language or date of publication when searching the electronic databases. Parallel randomised controlled trials (RCTs) comparing slow-release fluoride devices with an alternative fluoride treatment, placebo, or no intervention in all age groups. The main outcome measures sought were changes in numbers of decayed, missing, and filled teeth or surfaces (DMFT/DMFS in permanent teeth or dmft/dmfs in primary teeth), and progression of carious lesions through enamel and into dentine. We conducted data collection and analysis using standard Cochrane review methods. At least two review authors independently performed all the key steps in the review such as screening of abstracts, application of inclusion criteria, data extraction, and risk of bias assessment. We resolved discrepancies through discussions or arbitration by a third or fourth review author. We found no evidence comparing slow

Force-velocity measurements of a few growing actin filaments.

Directory of Open Access Journals (Sweden)

Coraline Brangbour

2011-04-01

Full Text Available The polymerization of actin in filaments generates forces that play a pivotal role in many cellular processes. We introduce a novel technique to determine the force-velocity relation when a few independent anchored filaments grow between magnetic colloidal particles. When a magnetic field is applied, the colloidal particles assemble into chains under controlled loading or spacing. As the filaments elongate, the beads separate, allowing the force-velocity curve to be precisely measured. In the widely accepted Brownian ratchet model, the transduced force is associated with the slowing down of the on-rate polymerization. Unexpectedly, in our experiments, filaments are shown to grow at the same rate as when they are free in solution. However, as they elongate, filaments are more confined in the interspace between beads. Higher repulsive forces result from this higher confinement, which is associated with a lower entropy. In this mechanism, the production of force is not controlled by the polymerization rate, but is a consequence of the restriction of filaments' orientational fluctuations at their attachment point.

Kinematic Mechanisms of How Power Training Improves Healthy Old Adults' Gait Velocity.

Science.gov (United States)

Beijersbergen, Chantal M I; Granacher, Urs; Gäbler, Martijn; Devita, Paul; Hortobágyi, Tibor

2017-01-01

Slow gait predicts many adverse clinical outcomes in old adults, but the mechanisms of how power training can minimize the age-related loss of gait velocity is unclear. We examined the effects of 10 wk of lower extremity power training and detraining on healthy old adults' lower extremity muscle power and gait kinematics. As part of the Potsdam Gait Study, participants started with 10 wk of power training followed by 10 wk of detraining (n = 16), and participants started with a 10-wk control period followed by 10 wk of power training (n = 16). We measured gait kinematics (stride characteristic and joint kinematics) and isokinetic power of the ankle plantarflexor (20°·s, 40°·s, and 60°·s) and knee extensor and flexor (60°·s, 120°·s, and 180°·s) muscles at weeks 0, 10, and 20. Power training improved isokinetic muscle power by ~30% (P ≤ 0.001) and fast (5.9%, P kinematics did not correlate with increases in fast gait velocity. The mechanisms that increased fast gait velocity involved higher cadence (r = 0.86, P ≤ 0.001) rather than longer strides (r = 0.49, P = 0.066). Detraining did not reverse the training-induced increases in muscle power and fast gait velocity. Because increases in muscle power and modifications in joint kinematics did not correlate with increases in fast gait velocity, kinematic mechanisms seem to play a minor role in improving healthy old adults' fast gait velocity after power training.

High-energy monoenergetic proton beams from two stage acceleration with a slow laser pulse

Directory of Open Access Journals (Sweden)

H. Y. Wang

2015-02-01

Full Text Available We present a new regime to generate high-energy quasimonoenergetic proton beams in a “slow-pulse” regime, where the laser group velocity v_{g}velocity, ions initially accelerated by the light sail (LS mode can be further trapped and reflected by the snowplough potential generated by the laser in the near-critical density plasma. These two acceleration stages are connected by the onset of Rayleigh-Taylor-like (RT instability. The usual ion energy spectrum broadening by RT instability is controlled and high quality proton beams can be generated. It is shown by multidimensional particle-in-cell simulation that quasimonoenergetic proton beams with energy up to hundreds of MeV can be generated at laser intensities of 10^{21}  W/cm^{2}.

Hip mechanics underlie lower extremity power training-induced increase in old adults' fast gait velocity : The Potsdam Gait Study (POGS)

NARCIS (Netherlands)

Beijersbergen, Chantal M. I.; Granacher, Urs; Gäbler, Martijn; DeVita, Paul; Hortobagyi, Tibor

Background: Aging is associated with slowed gait and old compared with young adults generally walk with greater positive hip work (H1) and reduced positive ankle work (A2). The role of exercise interventions on old adults' gait mechanics that underlie training-induced improvements in gait velocity

Cell proliferation of Paramecium tetraurelia on a slow rotating clinostat

Science.gov (United States)

Sawai, Satoe; Mogami, Yoshihiro; Baba, Shoji A.

Paramecium is known to proliferate faster under microgravity conditions, and slower under hypergravity. Experiments using axenic culture medium have demonstrated that hypergravity affected directly on the proliferation of Paramecium itself. In order to assess the mechanisms underlying the physiological effects of gravity on cell proliferation, Paramecium tetraurelia was grown under clinorotation (2.5 rpm) and the time course of the proliferation was investigated in detail on the basis of the logistic analysis. On the basis of the mechanical properties of Paramecium, this slow rate of the rotation appears to be enough to simulate microgravity in terms of the randomization of the cell orientation with respect to gravity. P. tetraurelia was cultivated in a closed chamber in which cells were confined without air bubbles, reducing the shear forces and turbulences under clinorotation. The chamber is made of quartz and silicone rubber film; the former is for the optically-flat walls for the measurement of cell density by means of a non-invasive laser optical-slice method, and the latter for gas exchange. Because of the small dimension for culture space, Paramecium does not accumulate at the top of the chamber in spite of its known negative gravitactic behavior. We measured the cell density at regular time intervals without breaking the configuration of the chamber, and analyzed the proliferation parameters by fitting the data to a logistic equation. As a result, P. tetraurelia showed reduced proliferation under slow clinorotation. The saturation of the cell density as well as the maximum proliferation rate decreased, although we found no significant changes on the half maximal time for proliferation. We also found that the mean swimming velocity decreased under slow clinorotation. These results were not consistent with those under microgravity and fast rotating clinostat. This may suggest that randomization of the cell orientation performed by slow rotating clinostat has

Bodily pleasure matters: Velocity of touch modulates body ownership during the rubber hand illusion

Directory of Open Access Journals (Sweden)

Laura eCrucianelli

2013-10-01

Full Text Available The sense of body ownership represents a fundamental aspect of our self-consciousness. Influential experimental paradigms, such as the rubber hand illusion (RHI, in which a seen rubber hand is experienced as part of one’s body when one’s own unseen hand receives congruent tactile stimulation, have extensively examined the role of exteroceptive, multisensory integration on body ownership. However, remarkably, despite the more general current interest in the nature and role of interoception in emotion and consciousness, no study has investigated how the illusion may be affected by interoceptive bodily signals, such as affective touch. Here, we recruited 52 healthy, adult participants and we investigated for the first time, whether applying slow velocity, light tactile stimuli, known to elicit interoceptive feelings of pleasantness, would influence the illusion more than faster, emotionally-neutral, tactile stimuli. We also examined whether seeing another person’s hand versus a rubber hand would reduce the illusion in slow versus fast stroking conditions, as interoceptive signals are used to represent one’s own body from within and it is unclear how they would be integrated with visual signals from another person’s hand. We found that slow velocity touch was perceived as more pleasant and it produced higher levels of subjective embodiment during the RHI compared with fast touch. Moreover, this effect applied irrespective of whether the seen hand was a rubber or a confederate’s hand. These findings provide support for the idea that affective touch, and more generally interoception, may have a unique contribution to the sense of body ownership, and by implication to our embodied psychological self.

[Research progress of Chinese herbal medicine and traditional Chinese medicine resulting in liver injury].

Science.gov (United States)

Wang, Jingli; Zhou, Chaofan

2011-12-01

The adverse reactions caused by Chinese herbal medicine and traditional Chinese medicine are reported increased in recent years, among which the acute liver injury caused by Chinese herbal medicine accounts for 21.5% of total liver injuries. Despite the misuse of traditional Chinese medicine not in accordance with differentiation of symptoms and signs, the adverse reaction of Chinese herbal medicine itself can't be little to these adverse events. The paper summarizes the most common categories of traditional Chinese medicine resulting in liver injury, the mechanism, pathological characteristics, clinical symptom of liver injury, the reasons of the reaction and how to prevent. The research aims to enhance the clinical physician recognition of liver injury caused by Chinese herbal medicine, in order to ensure the safe and rational usage of traditional Chinese medicine.

Slow Earthquake Hunters: A New Citizen Science Project to Identify and Catalog Slow Slip Events in Geodetic Data

Science.gov (United States)

Bartlow, N. M.

2017-12-01

Slow Earthquake Hunters is a new citizen science project to detect, catalog, and monitor slow slip events. Slow slip events, also called "slow earthquakes", occur when faults slip too slowly to generate significant seismic radiation. They typically take between a few days and over a year to occur, and are most often found on subduction zone plate interfaces. While not dangerous in and of themselves, recent evidence suggests that monitoring slow slip events is important for earthquake hazards, as slow slip events have been known to trigger damaging "regular" earthquakes. Slow slip events, because they do not radiate seismically, are detected with a variety of methods, most commonly continuous geodetic Global Positioning System (GPS) stations. There is now a wealth of GPS data in some regions that experience slow slip events, but a reliable automated method to detect them in GPS data remains elusive. This project aims to recruit human users to view GPS time series data, with some post-processing to highlight slow slip signals, and flag slow slip events for further analysis by the scientific team. Slow Earthquake Hunters will begin with data from the Cascadia subduction zone, where geodetically detectable slow slip events with a duration of at least a few days recur at regular intervals. The project will then expand to other areas with slow slip events or other transient geodetic signals, including other subduction zones, and areas with strike-slip faults. This project has not yet rolled out to the public, and is in a beta testing phase. This presentation will show results from an initial pilot group of student participants at the University of Missouri, and solicit feedback for the future of Slow Earthquake Hunters.

Zero-Dispersion Slow Light with Wide Bandwidth in Photonic Crystal Coupled Waveguides

International Nuclear Information System (INIS)

Xiao-Yu, Mao; Geng-Yan, Zhang; Yi-Dong, Huang; Wei, Zhang; Jiang-De, Peng

2008-01-01

By introducing an adjustment waveguide besides the incident waveguide, zero-dispersion slow light with wide bandwidth can be realized due to anticrossing of the incident waveguide mode and the adjustment waveguide mode. The width of the adjustment waveguide (W 2 ) and the hole radii of the coupling region (r') will change the dispersion of incident waveguide mode. Theoretical investigation reveals that zero dispersion at various low group velocity ν g in incident waveguide can be achieved. In particular, proper W 2 and r' can lead to the lowest ν g of 0.0085c at 1550 nm with wide bandwidth of 202 GHz for zero dispersion

A slowing-down problem

Energy Technology Data Exchange (ETDEWEB)

Carlvik, I; Pershagen, B

1958-06-15

An infinitely long circular cylinder of radius a is surrounded by an infinite moderator. Both media are non-capturing. The cylinder emits neutrons of age zero with a constant source density of S. We assume that the ratios of the slowing-down powers and of the diffusion constants are independent of the neutron energy. The slowing-down density is calculated for two cases, a) when the slowing-down power of the cylinder medium is very small, and b) when the cylinder medium is identical with the moderator. The ratios of the slowing-down density at the age {tau} and the source density in the two cases are called {psi}{sub V}, and {psi}{sub M} respectively. {psi}{sub V} and {psi}{sub M} are functions of y=a{sup 2}/4{tau}. These two functions ({psi}{sub V} and {psi}{sub M}) are calculated and tabulated for y = 0-0.25.

Digital health is a cultural transformation of traditional healthcare

OpenAIRE

Meskó, Bertalan; Drobni, Zsófia; Bényei, Éva; Gergely, Bence; Győrffy, Zsuzsanna

2017-01-01

Under the term “digital health”, advanced medical technologies, disruptive innovations and digital communication have gradually become inseparable from providing best practice healthcare. While the cost of treating chronic conditions is increasing and doctor shortages are imminent worldwide, the needed transformation in the structure of healthcare and medicine fails to catch up with the rapid progress of the medical technology industry. This transition is slowed down by strict regulations; th...

Frictional properties of the Nankai frontal thrust explain recurring shallow slow slip events

Science.gov (United States)

Saffer, D. M.; Ikari, M.; Kopf, A.; Roesner, A.

2017-12-01

Recent observations provide evidence for shallow slip reaching to the trench on subduction megathrusts, both in earthquakes and slow slip events (SSE). This is at odds with existing friction studies, which report primarily velocity-strengthening behavior (friction increases with slip velocity) for subduction fault material and synthetic analogs, which leads only to stable sliding. We report on direct shearing experiments on fault rocks from IODP Site C0007, which sampled the frontal thrust of the Nankai accretionary prism. This fault has been implicated in both coseimic slip and recurring SSE. We focus on material from 437.2 meters below seafloor, immediately above a localized shear zone near the base of the fault. In our experiments, a 25 mm diameter cylindrical specimen is loaded in an assembly of two steel plates. After application of normal stress (3, 10, or 17 MPa) and subsequent equilibration, the lower plate is driven at a constant velocity while the upper plate remains stationary; this configuration forces shear to localize between the two plates. After reaching a steady state residual friction coefficient (µss), we conducted velocity-stepping tests to measure the friction rate parameter (a-b), defined as the change in friction for a change in velocity: (a-b) = Δuss/ln(V/Vo), over a range of velocities from 0.1-100 µm s-1. We find that µss ranges from 0.26 to 0.32 and exhibits a slight decrease with normal stress. We observe velocity-weakening behavior at low normal stresses (3-10 MPa) and for low sliding velocities (30 µm s-1. At higher normal stress (17 MPa), we observe dominantly velocity-strengthening, consistent with previously reported measurements for 25 MPa normal stress. Our observation of rate weakening at slip rates matching those of SSE in the outer Nankai forearc provide a potential explanation for periodic strain accumulation and subsequent release during SSE near the trench. The observation of rate weakening behavior only at low normal

Rotating Hele-Shaw cell with a time-dependent angular velocity

Science.gov (United States)

Anjos, Pedro H. A.; Alvarez, Victor M. M.; Dias, Eduardo O.; Miranda, José A.

2017-12-01

Despite the large number of existing studies of viscous flows in rotating Hele-Shaw cells, most investigations analyze rotational motion with a constant angular velocity, under vanishing Reynolds number conditions in which inertial effects can be neglected. In this work, we examine the linear and weakly nonlinear dynamics of the interface between two immiscible fluids in a rotating Hele-Shaw cell, considering the action of a time-dependent angular velocity, and taking into account the contribution of inertia. By using a generalized Darcy's law, we derive a second-order mode-coupling equation which describes the time evolution of the interfacial perturbation amplitudes. For arbitrary values of viscosity and density ratios, and for a range of values of a rotational Reynolds number, we investigate how the time-dependent angular velocity and inertia affect the important finger competition events that traditionally arise in rotating Hele-Shaw flows.

Plasma heating and confinement in toroidal magnetic bottle by means of microwave slowing-down structure

International Nuclear Information System (INIS)

Datlov, J.; Klima, R.; Kopecky, V.; Musil, J.; Zacek, F.

1977-01-01

An invention is described concerning high-frequency plasma heating and confinement in toroidal magnetic vessels. Microwave energy is applied to the plasma via one or more slowing-down structures exciting low phase velocity waves whose energy may be efficiently absorbed by plasma electrons. The wave momentum transfer results in a toroidal electrical current whose magnetic field together with an external magnetic field ensure plasma confinement. The low-frequency modulation of microwave energy may also be used for heating the ion plasma component. (J.U.)

Rapidly Progressive Quadriplegia and Encephalopathy.

Science.gov (United States)

Wynn, DonRaphael; McCorquodale, Donald; Peters, Angela; Juster-Switlyk, Kelsey; Smith, Gordon; Ansari, Safdar

2016-11-01

A woman aged 77 years was transferred to our neurocritical care unit for evaluation and treatment of rapidly progressive motor weakness and encephalopathy. Examination revealed an ability to follow simple commands only and abnormal movements, including myoclonus, tongue and orofacial dyskinesias, and opsoclonus. Imaging study findings were initially unremarkable, but when repeated, they demonstrated enhancement of the cauda equina nerve roots, trigeminal nerve, and pachymeninges. Cerebrospinal fluid examination revealed mildly elevated white blood cell count and protein levels. Serial electrodiagnostic testing demonstrated a rapidly progressive diffuse sensory motor axonopathy, and electroencephalogram findings progressed from generalized slowing to bilateral periodic lateralized epileptiform discharges. Critical details of her recent history prompted a diagnostic biopsy. Over time, the patient became completely unresponsive with no further abnormal movements and ultimately died. The differential diagnosis, pathological findings, and diagnosis are discussed with a brief review of a well-known yet rare diagnosis.

Velocity-specific strength recovery after a second bout of eccentric exercise.

Science.gov (United States)

Barss, Trevor S; Magnus, Charlene R A; Clarke, Nick; Lanovaz, Joel L; Chilibeck, Philip D; Kontulainen, Saija A; Arnold, Bart E; Farthing, Jonathan P

2014-02-01

A bout of eccentric exercise (ECC) has the protective effect of reducing muscle damage during a subsequent bout of ECC known as the "repeated bout effect" (RBE). The purpose of this study was to determine if the RBE is greater when both bouts of ECC are performed using the same vs. different velocity of contraction. Thirty-one right-handed participants were randomly assigned to perform an initial bout of either fast (3.14 rad·s [180°·s]) or slow (0.52 rad·s [30°·s]) maximal isokinetic ECCs of the elbow flexors. Three weeks later, the participants completed another bout of ECC at the same velocity (n = 16), or at a different velocity (n = 15). Indirect muscle damage markers were measured before, immediately after, and at 24, 48, and 72 hours postexercise. Measures included maximal voluntary isometric contraction (MVC) strength (dynamometer), muscle thickness (MT; ultrasound), delayed onset muscle soreness (DOMS; visual analog scale), biceps and triceps muscle activation amplitude (electromyography), voluntary activation (interpolated twitch), and twitch torque. After the repeated bout, MVC strength recovered faster compared with the same time points after the initial bout for only the same velocity group (p = 0.017), with no differences for all the other variables. Irrespective of velocity, MT and DOMS were reduced after the repeated bout compared with that of the initial bout at 24, 48, and 72 hours with a corresponding increase in TT at 72 hours (p effects contribute to the RBE. The current findings support the idea of multiple mechanisms contributing to the RBE.

Activated-Lignite-Based Super Large Granular Slow-Release Fertilizers Improve Apple Tree Growth: Synthesis, Characterizations, and Laboratory and Field Evaluations.

Science.gov (United States)

Tang, Yafu; Wang, Xinying; Yang, Yuechao; Gao, Bin; Wan, Yongshan; Li, Yuncong C; Cheng, Dongdong

2017-07-26

In this work, lignite, a low-grade coal, was modified using the solid-phase activation method with the aid of a Pd/CeO 2 nanoparticle catalyst to improve its pore structure and nutrient absorption. Results indicate that the adsorption ability of the activated lignite to NO 3 - , NH 4 + , H 2 PO 4 - , and K + was significantly higher than that of raw lignite. The activated lignite was successfully combined with the polymeric slow-release fertilizer, which exhibits typical slow-release behavior, to prepare the super large granular activated lignite slow-release fertilizer (SAF). In addition to the slow-release ability, the SAF showed excellent water-retention capabilities. Soil column leaching experiments further confirmed the slow-release characteristics of the SAF with fertilizer nutrient loss greatly reduced in comparison to traditional and slow-release fertilizers. Furthermore, field tests of the SAF in an orchard showed that the novel SAF was better than other tested fertilizers in improve the growth of young apple trees. Findings from this study suggest that the newly developed SAF has great potential to be used in apple cultivation and production systems in the future.

Effect of biologic therapy on radiological progression in rheumatoid arthritis: what does it add to methotrexate?

Directory of Open Access Journals (Sweden)

Jones G

2012-07-01

Full Text Available Graeme Jones, Erica Darian-Smith, Michael Kwok, Tania WinzenbergMenzies Research Institute, University of Tasmania, Tasmania, AustraliaAbstract: There have been substantial advances in the treatment of rheumatoid arthritis in recent years. Traditional disease-modifying antirheumatic drugs (DMARDs have been shown to have small effects on the progression of radiographic damage. This quantitative overview summarizes the evidence for biologic DMARDS and radiographic damage either alone or in combination with methotrexate. Two outcomes were used (standardized mean difference and odds of progression. A total of 21 trials were identified of which 18 had useable data. For biologic monotherapy, tocilizumab, adalimumab, and etanercept were significantly better than methotrexate, with tocilizumab ranking first in both outcomes while golimumab was ineffective in both outcomes. For a biologic in combination with methotrexate compared with methotrexate alone, most therapies studied (etanercept, adalimumab, infliximab, certolizumab, tocilizumab, and rituximab were effective at slowing X-ray progression using either outcome, with infliximab ranking first in both outcomes. The exceptions to this were golimumab (no effect on standardized mean difference and abatacept (no effect on odds of progression. This effect was additional to methotrexate; thus, the overall benefit is moderate to large in magnitude, which is clearly of major clinical significance for sufferers of rheumatoid arthritis and supports the use of biologic DMARDs in those with a poor disease prognosis.Keywords: rheumatoid, trials, meta-analysis, radiographs, biologic, disease-modifying antirheumatic drugs, DMARDs

"Paideia," Progress, Puzzlement

Science.gov (United States)

Hrachovec, Herbert

2018-01-01

Platonic "paideia" is a mainstream concept in traditional philosophy and humanistic circles generally. It is closely connected with social progress brought about by the dynamics of enlightenment and self-fulfillment, symbolized by the allegory of the cave. The main contention of this paper is that the philosophical grammar of this simile…

Progression of emphysema evaluated by MRI using hyperpolarized (3)He (HP (3)He) measurements in patients with alpha-1-antitrypsin (A1AT) deficiency compared with CT and lung function tests

DEFF Research Database (Denmark)

Stavngaard, T; Søgaard, L Vejby; Batz, M

2009-01-01

BACKGROUND: The progression of emphysema is traditionally measured by pulmonary function test, with forced expiratory volume in 1 s (FEV(1)) being the most accepted and used measurement. However, FEV(1) is insensitive in detecting mild/slow progression of emphysema because of low reproducibility...... as compared to yearly decline. PURPOSE: To investigate the progression of emphysema over a period of 2 years using diffusion-weighted hyperpolarized (HP) (3)He magnetic resonance imaging (MRI) in patients with alpha-1-antitrypsin (A1AT) deficiency. MATERIAL AND METHODS: Nine patients with severe A1AT...... density [CT-PD15] and relative area of emphysema below -910 HU [CT-RA-910]). RESULTS: Seven patients were scanned three times, one patient two times, and one patient only at baseline. The mean increase in ADC values from first to last HP (3)He MR scanning was 3.8% (0.014 cm(2)/s [SD 0.024 cm(2)/s...

[Progress of sulfur fumigation and modern processing technology of Chinese traditional medicines].

Science.gov (United States)

Lu, Tu-Lin; Shan, Xin; Li, Lin; Mao, Chun-Qin; Ji, De; Yin, Fang-Zhou; Lang, Yong-Ying

2014-08-01

Infestation, moldy and other phenomenon in the processing and storage of Chinese herbal medicines is a problem that faced in the production of Chinese traditional medicine. The low productivity of traditional processing methods can not guarantee the quality of Chinese herbal medicines. Sulfur fumigation is the first choice of grassroots to process the Chinese herbal medicine with its low cost and easy operation. Sulfur fumigation can solve some problems in the processing and storage of Chinese herbal medicines, but modern pharmacological studies show that long-term use of Chinese traditional medicine which is fumigated by sulfur can cause some serious harm to human liver, kidney and other organs. This paper conducts a review about the application history of sulfur fumigation, its influence to the quality of Chinese herbal medicines as well as domestic and foreign limits to sulfur quantity, and a brief introduction of the status of modern processing technologies in the processing of food and some Chinese herbal medicines, the problems ex- isting in the Chinese herbal medicines processing, which can provide a reference basis for the further research, development and application of investigating alternative technologies of sulfur fumigation.

Quantitative muscle MRI as an assessment tool for monitoring disease progression in LGMD2I

DEFF Research Database (Denmark)

Willis, Tracey A; Hollingsworth, Kieren G; Coombs, Anna

2013-01-01

Outcome measures for clinical trials in neuromuscular diseases are typically based on physical assessments which are dependent on patient effort, combine the effort of different muscle groups, and may not be sensitive to progression over short trial periods in slow-progressing diseases. We hypoth...

Slow-wave metamaterial open panels for efficient reduction of low-frequency sound transmission

Science.gov (United States)

Yang, Jieun; Lee, Joong Seok; Lee, Hyeong Rae; Kang, Yeon June; Kim, Yoon Young

2018-02-01

Sound transmission reduction is typically governed by the mass law, requiring thicker panels to handle lower frequencies. When open holes must be inserted in panels for heat transfer, ventilation, or other purposes, the efficient reduction of sound transmission through holey panels becomes difficult, especially in the low-frequency ranges. Here, we propose slow-wave metamaterial open panels that can dramatically lower the working frequencies of sound transmission loss. Global resonances originating from slow waves realized by multiply inserted, elaborately designed subwavelength rigid partitions between two thin holey plates contribute to sound transmission reductions at lower frequencies. Owing to the dispersive characteristics of the present metamaterial panels, local resonances that trap sound in the partitions also occur at higher frequencies, exhibiting negative effective bulk moduli and zero effective velocities. As a result, low-frequency broadened sound transmission reduction is realized efficiently in the present metamaterial panels. The theoretical model of the proposed metamaterial open panels is derived using an effective medium approach and verified by numerical and experimental investigations.

Aggregate Settling Velocities in San Francisco Estuary Margins

Science.gov (United States)

Allen, R. M.; Stacey, M. T.; Variano, E. A.

2015-12-01

One way that humans impact aquatic ecosystems is by adding nutrients and contaminants, which can propagate up the food web and cause blooms and die-offs, respectively. Often, these chemicals are attached to fine sediments, and thus where sediments go, so do these anthropogenic influences. Vertical motion of sediments is important for sinking and burial, and also for indirect effects on horizontal transport. The dynamics of sinking sediment (often in aggregates) are complex, thus we need field data to test and validate existing models. San Francisco Bay is well studied and is often used as a test case for new measurement and model techniques (Barnard et al. 2013). Settling velocities for aggregates vary between 4*10-5 to 1.6*10-2 m/s along the estuary backbone (Manning and Schoellhamer 2013). Model results from South San Francisco Bay shoals suggest two populations of settling particles, one fast (ws of 9 to 5.8*10-4 m/s) and one slow (ws of Brand et al. 2015). While the open waters of San Francisco Bay and other estuaries are well studied and modeled, sediment and contaminants often originate from the margin regions, and the margins remain poorly characterized. We conducted a 24 hour field experiment in a channel slough of South San Francisco Bay, and measured settling velocity, turbulence and flow, and suspended sediment concentration. At this margin location, we found average settling velocities of 4-5*10-5 m/s, and saw settling velocities decrease with decreasing suspended sediment concentration. These results are consistent with, though at the low end of, those seen along the estuary center, and they suggest that the two population model that has been successful along the shoals may also apply in the margins.

Impacts into Coarse-Grained Spheres at Moderate Impact Velocities: Implications for Cratering on Asteroids and Planets

Science.gov (United States)

Barnouin, Olivier S.; Daly, R. Terik; Cintala, Mark J.; Crawford, David A.

2018-01-01

The surfaces of many planets and asteroids contain coarsely fragmental material generated by impacts or other geologic processes. The presence of such pre-existing structures may affect subsequent impacts, particularly when the width of the shock is comparable to or smaller than the size of pre-existing structures. Reasonable theoretical predictions and low speed (<300m/s) impact experiments suggest that in such targets the cratering process should be highly dissipative, which would reduce cratering efficiencies and cause a rapid decay in ejection velocity as a function of distance from the impact point. In this study, we assess whether these results apply at higher impact speeds between 0.5 and 2.5 km s-1. This study shows little change in cratering efficiency when 3.18 mm diameter glass beads are launched into targets composed of these same beads. These impacts are very efficient, and ejection velocity decays slowly as function of distance from the impact point. This slow decay in ejection velocity probably indicates a correspondingly slow decay of the shock stresses. However, these experiments reveal that initial interactions between projectile and target strongly influence the cratering process and lead to asymmetries in crater shape and ejection angles, as well as significant variations in ejection velocity at a given launch position. Such effects of asymmetric coupling could be further enhanced by heterogeneity in the initial distribution of grains in the target and by mechanical collisions between grains. These experiments help to explain why so few craters are seen on the rubble-pile asteroid Itokawa: impacts into its coarsely fragmental surface by projectiles comparable to or smaller than the size of these fragments likely yield craters that are not easily recognizable.

A new state-of-the-art tool to investigate rock friction under extreme slip velocities and accelerations: SHIVA

Science.gov (United States)

Niemeijer, André; di Toro, Giulio; Nielsen, Stefan; Scarlato, Piergiorgio; Romeo, Gianni; di Stefano, Giuseppe; Smith, Steven; di Felice, Fabio; Mariano, Sofia

2010-05-01

Despite considerable effort over the past several decades, the mechanics of earthquakes rupture remain largely unknown. In order to complement fault drilling projects and field and seismological observations, recent friction experiments strive to reproduce as closely as possible in-situ (natural) conditions of slip velocity and acceleration on intact and fault rocks. In this contribution, we present a novel state-of-the-art experimental rotary shear apparatus (SHIVA or Slow to HIgh Velocity Apparatus) capable of shearing samples at sliding velocities up to 10 m/s, accelerations of ~ 40 m/s2 and normal stresses up to 50 MPa. In comparison with existing high speed friction machines, this apparatus extends the range of sliding velocities, normal stresses, sample size and, more importantly, accelerations. The apparatus consists of a pair of brushless electric motors (a low velocity motor, 10-6-10-3 m/s, power 5 kW, and a high velocity motor, 10-3 - 10 m/s, power 270 kW), that are connected by a gear system that allows a switch between motors without loss of velocity and force. The motors drive a rotary shaft which clamps ring-shaped samples (diameter 40- 50 mm). On the other side of the rotary shaft, a stationary shaft holds the other half of the sample assembly. The shaft is held stationary by a pair of stainless steel arms, one of which is attached to the side of the concrete-filled base where torque is measured by a tension cell. Axial force (maximum 37 kN) is applied on this side by a piston-cylinder couple with an arm to increase the force. The entire machine measures by 3.5 by 1.2 meters and weighs 3700 kg. We aim to perform experiments on rock samples of a variety of compositions using slip velocities and accelerations that simulate slip velocity functions that occur during earthquakes. In addition, we plan to develop a pore fluid system and a pressure vessel in order to perform experiments that include the physical-chemical processes that occur during slow

Effect of movement velocity on the relationship between training load and the number of repetitions of bench press.

Science.gov (United States)

Sakamoto, Akihiro; Sinclair, Peter J

2006-08-01

This study investigated the effect of movement velocity on the relationship between loading intensity and the number of repetitions of bench press. Thirteen healthy men (age = 21.7 +/- 1.0 years; weight = 76.8 +/- 2.5 kg; 1 repetition maximum [1RM] = 99.5 +/- 6.0 kg), who were involved in regular weight training, voluntarily participated in the experiment. Subjects performed bench presses on a Smith machine at 5 different intensities (40-80% 1RM), repeated for 4 velocity conditions (slow: 0.15 +/- 0.03 m.s(-1); medium: 0.32 +/- 0.07 m.s(-1); fast: 0.52 +/- 0.12 m.s(-1); ballistic: maximum velocity), which were randomly assigned over 5 experimental sessions after a 1RM test. Velocity significantly changed the relationship between intensity (%1RM) and the number of reps performed (p velocities producing a higher number of reps. A significant interaction between intensity and velocity meant that velocity had a much greater effect on repetitions at lower intensities. These results suggest that the benefits of using a stretch-shortening cycle during faster movements outweigh the associated disadvantages from the force-velocity relationship. The practical applications of this study are that, when trainees are assigned a resistance training with specific RM values, the lifted intensity (%1RM) or weights will not be consistent unless velocity is controlled during training.

Integrated Photonics Enabled by Slow Light

DEFF Research Database (Denmark)

Mørk, Jesper; Chen, Yuntian; Ek, Sara

2012-01-01

In this talk we will discuss the physics of slow light in semiconductor materials and in particular the possibilities offered for integrated photonics. This includes ultra-compact slow light enabled optical amplifiers, lasers and pulse sources.......In this talk we will discuss the physics of slow light in semiconductor materials and in particular the possibilities offered for integrated photonics. This includes ultra-compact slow light enabled optical amplifiers, lasers and pulse sources....

Fast and slow spindles during the sleep slow oscillation: disparate coalescence and engagement in memory processing.

Science.gov (United States)

Mölle, Matthias; Bergmann, Til O; Marshall, Lisa; Born, Jan

2011-10-01

Thalamo-cortical spindles driven by the up-state of neocortical slow (memory consolidation during sleep. We examined interactions between SOs and spindles in human slow wave sleep, focusing on the presumed existence of 2 kinds of spindles, i.e., slow frontocortical and fast centro-parietal spindles. Two experiments were performed in healthy humans (24.5 ± 0.9 y) investigating undisturbed sleep (Experiment I) and the effects of prior learning (word paired associates) vs. non-learning (Experiment II) on multichannel EEG recordings during sleep. Only fast spindles (12-15 Hz) were synchronized to the depolarizing SO up-state. Slow spindles (9-12 Hz) occurred preferentially at the transition into the SO down-state, i.e., during waning depolarization. Slow spindles also revealed a higher probability to follow rather than precede fast spindles. For sequences of individual SOs, fast spindle activity was largest for "initial" SOs, whereas SO amplitude and slow spindle activity were largest for succeeding SOs. Prior learning enhanced this pattern. The finding that fast and slow spindles occur at different times of the SO cycle points to disparate generating mechanisms for the 2 kinds of spindles. The reported temporal relationships during SO sequences suggest that fast spindles, driven by the SO up-state feed back to enhance the likelihood of succeeding SOs together with slow spindles. By enforcing such SO-spindle cycles, particularly after prior learning, fast spindles possibly play a key role in sleep-dependent memory processing.

Light storage via slow-light four-wave mixing

International Nuclear Information System (INIS)

Fan, Yun-Fei; Wang, Hai-Hua; Wei, Xiao-Gang; Li, Ai-Jun; Kang, Zhi-Hui; Wu, Jin-Hui; Zhang, Han-Zhuang; Xu, Huai-Liang; Gao, Jin-Yue

2012-01-01

We experimentally demonstrate a light storage via slow-light four-wave mixing in a solid-state medium with a four-level double lambda scheme. Using slow light based on electromagnetically induced transparency, we obtain a slowed four-wave mixing signal pulse together with the slowed probe pulse. During the propagation of light pulses, the storage and retrieval of both the slowed four-wave mixing pulse and the slowed probe pulse are studied by manipulating the intensities of the control fields. -- Highlights: ► A light storage via slow-light four-wave mixing is observed in a solid. ► The probe pulse is slowed under electromagnetically induced transparency. ► A slowed four-wave mixing pulse is obtained by slow light. ► The storage of slowed double pulses is studied.

Effects space velocity and gas velocity on DeNOx catalyst with HC reductant; HC tenka NOx kangen shokubai no kukan sokudo oyobi gas ryusoku no eikyo

Energy Technology Data Exchange (ETDEWEB)

Niimura, K.; Tsujimura, K.

1995-04-20

Discussions were given on the hydrocarbon added reduction catalyst method to reduce NOx in diesel engine exhaust gas. An experiment was carried out with actual exhaust gas from a diesel engine by using a copper ion exchanged zeolite catalyst that has been coated on a honeycomb type substrate, and using propylene as a reductant. When the catalyst volume was changed with the exhaust gas space velocity kept constant, the NOx conversion ratio decreased as the catalyst length is decreased, and the activity shifted to the lower temperature side. The NOx reduction efficiency increased if the faster the gas flow velocity. On the other hand, if the gas flow velocity is slow, the NOx reduction can be carried out with relatively small amount of the reductant. When the catalyst volume was changed with the passing gas amount kept constant, the NOx conversion ratio decreased largely if the catalyst length is decreased. Further, the NOx reduction characteristics shift to the higher temperature side. In the catalyst length direction, the NOx reduction activity shows a relatively uniform action. However, a detailed observation reveals that the reaction heat in the catalyst is transmitted to the wake improving the activity, hence the further down the flow, the NOx conversion ratio gets higher in efficiency. 5 refs., 5 figs., 3 tabs.

Synthetic spectral analysis of a kinetic model for slow-magnetosonic waves in solar corona

Energy Technology Data Exchange (ETDEWEB)

Ruan, Wenzhi; He, Jiansen; Tu, Chuanyi; Wang, Linghua [School of Earth and Space Sciences, Peking University, Beijing, 100871, China, E-mail: jshept@gmail.com (China); Zhang, Lei [State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190 (China); Vocks, Christian [Leibniz-Institut für Astrophysik Potsdam, 14482, Potsdam (Germany); Marsch, Eckart [Institute for Experimental and Applied Physics, Christian-Albrechts-Universität zu Kiel, 24118 Kiel (Germany); Peter, Hardi [Max Plank Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen (Germany)

2016-03-25

We propose a kinetic model of slow-magnetosonic waves to explain various observational features associated with the propagating intensity disturbances (PIDs) occurring in the solar corona. The characteristics of slow mode waves, e.g, inphase oscillations of density, velocity, and thermal speed, are reproduced in this kinetic model. Moreover, the red-blue (R-B) asymmetry of the velocity distribution as self-consistently generated in the model is found to be contributed from the beam component, as a result of the competition between Landau resonance and Coulomb collisions. Furthermore, we synthesize the spectral lines and make the spectral analysis, based on the kinetic simulation data of the flux tube plasmas and the hypothesis of the surrounding background plasmas. It is found that the fluctuations of parameters of the synthetic spectral lines are basically consistent with the observations: (1) the line intensity, Doppler shift, and line width are fluctuating in phase; (2) the R-B asymmetry usually oscillate out of phase with the former three parameters; (3) the blueward asymmetry is more evident than the redward asymmetry in the R-B fluctuations. The oscillations of line parameters become weakened for the case with denser surrounding background plasmas. Similar to the observations, there is no doubled-frequency oscillation of the line width for the case with flux-tube plasmas flowing bulkly upward among the static background plasmas. Therefore, we suggest that the “wave + beam flow” kinetic model may be a viable interpretation for the PIDs observed in the solar corona.

CONSTRAINING THE NFW POTENTIAL WITH OBSERVATIONS AND MODELING OF LOW SURFACE BRIGHTNESS GALAXY VELOCITY FIELDS

International Nuclear Information System (INIS)

Kuzio de Naray, Rachel; McGaugh, Stacy S.; Mihos, J. Christopher

2009-01-01

We model the Navarro-Frenk-White (NFW) potential to determine if, and under what conditions, the NFW halo appears consistent with the observed velocity fields of low surface brightness (LSB) galaxies. We present mock DensePak Integral Field Unit (IFU) velocity fields and rotation curves of axisymmetric and nonaxisymmetric potentials that are well matched to the spatial resolution and velocity range of our sample galaxies. We find that the DensePak IFU can accurately reconstruct the velocity field produced by an axisymmetric NFW potential and that a tilted-ring fitting program can successfully recover the corresponding NFW rotation curve. We also find that nonaxisymmetric potentials with fixed axis ratios change only the normalization of the mock velocity fields and rotation curves and not their shape. The shape of the modeled NFW rotation curves does not reproduce the data: these potentials are unable to simultaneously bring the mock data at both small and large radii into agreement with observations. Indeed, to match the slow rise of LSB galaxy rotation curves, a specific viewing angle of the nonaxisymmetric potential is required. For each of the simulated LSB galaxies, the observer's line of sight must be along the minor axis of the potential, an arrangement that is inconsistent with a random distribution of halo orientations on the sky.

A study of the river velocity measurement techniques and analysis methods

Science.gov (United States)

Chung Yang, Han; Lun Chiang, Jie

2013-04-01

Velocity measurement technology can be traced back to the pitot tube velocity measurement method in the 18th century and today's velocity measurement technology use the acoustic and radar technology, with the Doppler principle developed technology advances, in order to develop the measurement method is more suitable for the measurement of velocity, the purpose is to get a more accurate measurement data and with the surface velocity theory, the maximum velocity theory and the indicator theory to obtain the mean velocity. As the main research direction of this article is to review the literature of the velocity measurement techniques and analysis methods, and to explore the applicability of the measurement method of the velocity measurement instruments, and then to describe the advantages and disadvantages of the different mean velocity profiles analysis method. Adequate review of the references of this study will be able to provide a reference for follow-up study of the velocity measurement. Review velocity measurement literature that different velocity measurement is required to follow the different flow conditions measured be upgraded its accuracy, because each flow rate measurement method has its advantages and disadvantages. Traditional velocity instrument can be used at low flow and RiverRAD microwave radar or imaging technology measurement method may be applied in high flow. In the tidal river can use the ADCP to quickly measure river vertical velocity distribution. In addition, urban rivers may be used the CW radar to set up on the bridge, and wide rivers can be used RiverRAD microwave radar to measure the velocities. Review the relevant literature also found that using Ultrasonic Doppler Current Profiler with the Chiu's theory to the velocity of observing automation work can save manpower and resources to improve measurement accuracy, reduce the risk of measurement, but the great variability of river characteristics in Taiwan and a lot of drifting floating

Ice Velocity Variations of the Polar Record Glacier (East Antarctica Using a Rotation-Invariant Feature-Tracking Approach

Directory of Open Access Journals (Sweden)

Tingting Liu

2017-12-01

Full Text Available In this study, the ice velocity changes from 2004 to 2015 of the Polar Record Glacier (PRG in East Antarctica were investigated based on a feature-tracking method using Landsat-7 enhanced thematic mapper plus (ETM+ and Landsat-8 operational land imager (OLI images. The flow field of the PRG curves make it difficult to generate ice velocities in some areas using the traditional normalized cross-correlation (NCC-based feature-tracking method. Therefore, a rotation-invariant parameter from scale-invariant feature transform (SIFT is introduced to build a novel rotation-invariant feature-tracking approach. The validation was performed based on multi-source images and the making earth system data records for use in research environments (MEaSUREs interferometric synthetic aperture radar (InSAR-based Antarctica ice velocity map data set. The results indicate that the proposed method is able to measure the ice velocity in more areas and performs as well as the traditional NCC-based feature-tracking method. The sequential ice velocities obtained present the variations in the PRG during this period. Although the maximum ice velocity of the frontal margin of the PRG and the frontal iceberg reached about 900 m/a and 1000 m/a, respectively, the trend from 2004 to 2015 showed no significant change. Under the interaction of the Polar Times Glacier and the Polarforschung Glacier, both the direction and the displacement of the PRG were influenced. This impact also led to higher velocities in the western areas of the PRG than in the eastern areas. In addition, elevation changes and frontal iceberg calving also impacted the ice velocity of the PRG.

Remote determination of the velocity index and mean streamwise velocity profiles

Science.gov (United States)

Johnson, E. D.; Cowen, E. A.

2017-09-01

When determining volumetric discharge from surface measurements of currents in a river or open channel, the velocity index is typically used to convert surface velocities to depth-averaged velocities. The velocity index is given by, k=Ub/Usurf, where Ub is the depth-averaged velocity and Usurf is the local surface velocity. The USGS (United States Geological Survey) standard value for this coefficient, k = 0.85, was determined from a series of laboratory experiments and has been widely used in the field and in laboratory measurements of volumetric discharge despite evidence that the velocity index is site-specific. Numerous studies have documented that the velocity index varies with Reynolds number, flow depth, and relative bed roughness and with the presence of secondary flows. A remote method of determining depth-averaged velocity and hence the velocity index is developed here. The technique leverages the findings of Johnson and Cowen (2017) and permits remote determination of the velocity power-law exponent thereby, enabling remote prediction of the vertical structure of the mean streamwise velocity, the depth-averaged velocity, and the velocity index.

Graphene based silicon–air grating structure to realize electromagnetically-induced-transparency and slow light effect

Energy Technology Data Exchange (ETDEWEB)

Wei, Buzheng; Liu, Huaiqing [Key Lab of All Optical Network & Advanced Telecommunication Network of EMC, Beijing Jiaotong University, Beijing 100044 (China); Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044 (China); Ren, Guobin, E-mail: gbren@bjtu.edu.cn [Key Lab of All Optical Network & Advanced Telecommunication Network of EMC, Beijing Jiaotong University, Beijing 100044 (China); Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044 (China); Yang, Yuguang; Ye, Shen; Pei, Li; Jian, Shuisheng [Key Lab of All Optical Network & Advanced Telecommunication Network of EMC, Beijing Jiaotong University, Beijing 100044 (China); Institute of Lightwave Technology, Beijing Jiaotong University, Beijing 100044 (China)

2017-01-23

Highlights: • The EIT and slow light effect are achieved by our novel graphene based structure. • Excellent tunability of wide wavelength range can be obtained only by a small change in Fermi energy level. • The group velocity of incident light is reduced to more than 1/600 of that in vacuum. • Position control is realized by designing a graded period grating. - Abstract: A broad band tunable graphene based silicon–air grating structure is proposed. Electromagnetically-induced-transparency (EIT) window can be successfully tuned by virtually setting the desired Fermi energy levels on graphene sheets. Carrier mobility plays an important role in modulating the resonant depth. Furthermore, by changing the grating periods, light can be trapped at corresponding resonant positions where slow down factor is relatively larger than in the previous works. This structure can be used as a highly tunable optoelectronic device such as optical filter, broad-band modulator, plasmonic switches and buffers.

On the role of memory effects for dissipation and diffusion in slow collective nuclear motion

International Nuclear Information System (INIS)

Cassing, W.; Noerenberg, W.

1983-01-01

The energy dissipation in slow collective nuclear motion is viewed as a combined effect of a diabatic production of particle-hole excitations, leading to a conservative storage of collective energy, and a subsequent equilibration due to residual two-body collisions. The effective equation of motion for the collective degree of freedom turns out to be nonlocal in time due to the large mean free path of the nucleons and allows for a simultaneous description of two different attitudes of nuclear matter. The elastic response of heavy nuclei for ''fast'' collective motion switches over to pure friction for very slow collective motion. The time development of the fluctuations in the velocities may show oscillations for times comparable to the local equilibration time and hence, is qualitatively different from the classical limit. A first application of the diabatic dynamical approach is made for the quadrupole motion within a diabatic deformed harmonic oscillator basis. (orig.)

Final Technical Report for DOE Award DE-FG02-07ER64403 [Modeling of Microbially Induced Calcite Precipitation for the Immobilization of Strontium-90 Using a Variable Velocity Streamtube Ensemble

Energy Technology Data Exchange (ETDEWEB)

Ginn, Timothy R. [University of California, Davis; Weathers, Tess [University of California, Davis

2013-08-26

Biogeochemical modeling using PHREEQC2 and a streamtube ensemble approach is utilized to understand a well-to-well subsurface treatment system at the Vadose Zone Research Park (VZRP) near Idaho Falls, Idaho. Treatment involves in situ microbially-mediated ureolysis to induce calcite precipitation for the immobilization of strontium-90. PHREEQC2 is utilized to model the kinetically-controlled ureolysis and consequent calcite precipitation. Reaction kinetics, equilibrium phases, and cation exchange are used within PHREEQC2 to track pH and levels of calcium, ammonium, urea, and calcite precipitation over time, within a series of one-dimensional advective-dispersive transport paths creating a streamtube ensemble representation of the well-to-well transport. An understanding of the impact of physical heterogeneities within this radial flowfield is critical for remediation design; we address this via the streamtube approach: instead of depicting spatial extents of solutes in the subsurface we focus on their arrival distribution at the control well(s). Traditionally, each streamtube maintains uniform velocity; however in radial flow in homogeneous media, the velocity within any given streamtube is spatially-variable in a common way, being highest at the input and output wells and approaching a minimum at the midpoint between the wells. This idealized velocity variability is of significance in the case of ureolytically driven calcite precipitation. Streamtube velocity patterns for any particular configuration of injection and withdrawal wells are available as explicit calculations from potential theory, and also from particle tracking programs. To approximate the actual spatial distribution of velocity along streamtubes, we assume idealized radial non-uniform velocity associated with homogeneous media. This is implemented in PHREEQC2 via a non-uniform spatial discretization within each streamtube that honors both the streamtube’s travel time and the idealized “fast-slow

Thermistor based, low velocity isothermal, air flow sensor

International Nuclear Information System (INIS)

Cabrita, Admésio A C M; Mendes, Ricardo; Quintela, Divo A

2016-01-01

The semiconductor thermistor technology is applied as a flow sensor to measure low isothermal air velocities (<2 ms −1 ). The sensor is subjected to heating and cooling cycles controlled by a multifunctional timer. In the heating stage, the alternating current of a main AC power supply source guarantees a uniform thermistor temperature distribution. The conditioning circuit assures an adequate increase of the sensors temperature and avoids the thermal disturbance of the flow. The power supply interruption reduces the consumption from the source and extends the sensors life time. In the cooling stage, the resistance variation of the flow sensor is recorded by the measuring chain. The resistive sensor parameters proposed vary significantly and feature a high sensitivity to the flow velocity. With the aid of a computer, the data transfer, storage and analysis provides a great advantage over the traditional local anemometer readings. The data acquisition chain has a good repeatability and low standard uncertainties. The proposed method measures isothermal air mean velocities from 0.1 ms −1 to 2 ms −1 with a standard uncertainty error less than 4%. (paper)

Antioxidant vitamin and mineral supplements for slowing the progression of age-related macular degeneration.

Science.gov (United States)

Evans, Jennifer R; Lawrenson, John G

2017-07-31

It has been proposed that antioxidants may prevent cellular damage in the retina by reacting with free radicals that are produced in the process of light absorption. Higher dietary levels of antioxidant vitamins and minerals may reduce the risk of progression of age-related macular degeneration (AMD). The objective of this review was to assess the effects of antioxidant vitamin or mineral supplementation on the progression of AMD in people with AMD. We searched CENTRAL (2017, Issue 2), MEDLINE Ovid (1946 to March 2017), Embase Ovid (1947 to March 2017), AMED (1985 to March 2017), OpenGrey (System for Information on Grey Literature in Europe, the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 29 March 2017. We included randomised controlled trials (RCTs) that compared antioxidant vitamin or mineral supplementation (alone or in combination) to placebo or no intervention, in people with AMD. Both review authors independently assessed risk of bias in the included studies and extracted data. One author entered data into RevMan 5; the other author checked the data entry. We graded the certainty of the evidence using GRADE. We included 19 studies conducted in USA, Europe, China, and Australia. We judged the trials that contributed data to the review to be at low or unclear risk of bias.Nine studies compared multivitamins with placebo (7 studies) or no treatment (2 studies) in people with early and moderate AMD. The duration of supplementation and follow-up ranged from nine months to six years; one trial followed up beyond two years. Most evidence came from the Age-Related Eye Disease Study (AREDS) in the USA. People taking antioxidant vitamins were less likely to progress to late AMD (odds ratio

The modified connection formulae for the rotational transition cross sections in diatomic molecules for slow collisions

International Nuclear Information System (INIS)

Ostrovsky, V.N.; Ustimov, V.I.

1984-01-01

The formulae connecting the cross sections for various rotational transitions in diatomic molecules colliding with atomic particles are valid in the framework of the sudden approximation. In order to extend the applicability domain of these formulae to the slow-collision region a semi-empirical correction factor is introduced with an exponential dependence on the translation rotation energy transfer and on the inverse collision velocity. The modified connection formulae are applied to the rotational transitions in an HD molecule colliding with an H 2 molecule. (author)

Slow cryopreservation is not superior to vitrification in human spermatozoa; an experimental controlled study

Directory of Open Access Journals (Sweden)

Mohamed Shehata Ali Mohamed

2015-10-01

Full Text Available Background: Spermatozoa cryopreservation is used for the management of infertility and some other medical conditions. The routinely applied cryopreservation technique depends on permeating cryoprotectants, whose toxic effects have raised the attention towards permeating cryoprotectants-free vitrification technique. Objective: To compare between the application of slow cryopreservation and vitrification on human spermatozoa. Materials and Methods: This was an experimental controlled study involving 33 human semen samples, where each sample was divided into three equal parts; fresh control, conventional slow freezing, and permeating cryoprotectants-free vitrification. Viability and mitochondrial membrane potential (MMP of control and post-thawing spermatozoa were assessed with the sperm viability kit and the JC-1 kit, respectively, using fluorescence-activated cell sorting analysis. Results: Significant reduction of the progressive motility, viability and MMP was observed by the procedure of freezing and thawing, while there was not any significant difference between both cryopreservation techniques. Cryopreservation resulted in 48% reduction of the percentage of viable spermatozoa and 54.5% rise in the percentage of dead spermatozoa. In addition, high MMP was reduced by 24% and low MMP was increased by 34.75% in response to freezing and thawing. Progressive motility of spermatozoa was correlated significantly positive with high MMP and significantly negative with low MMP in control as well as post-thawing specimens (r=0.8881/ -0.8412, 0.7461/ -0.7510 and 0.7603/ -0.7839 for control, slow and vitrification respectively, p=0.0001. Conclusion: Although both cryopreservation techniques have similar results, vitrification is faster, easier and associated with less toxicity and costs. Thus, vitrification is recommended for the clinical application.

HYLIFE-2 progress report

International Nuclear Information System (INIS)

Moir, R.W.; Adamson, M.G.; Bangerter, R.O.; Bieri, R.L.; Condit, R.H.; Hartman, C.W.; House, P.A.; Langdon, A.B.; Logan, B.G.; Orth, C.D.; Petzoldt, R.W.; Pitts, J.H.; Post, R.F.; Sacks, R.A.; Tobin, M.T.; Williams, W.H.; Dolan, T.J.; Longhurst, G.R.; Hoffman, M.A.; Meier, W.R.

1991-12-01

LIFE-II inertial confinement fusion power plant design study uses a liquid fall, in the form of jets to protect the first structural wall from neutron damage, x rays, and blast to provide a 30-y lifetime. This is a progress report of an incomplete and ongoing study. HYLIFE-I used liquid lithium. HYLIFE-11 avoids the fire hazard of lithium by using a molten salt composed of fluorine, lithium, and beryllium (Li 2 Be 4 ) called Flibe. Access for heavy-ion beams is provided. Calculations for assumed heavy-ion beam performance show a nominal gain of 70 at 5 MJ producing 350 MJ, about 5.2 times less yield than the 1.8 GJ from a driver energy of 4.5 MJ with gain of 400 for HYLIFE-I. The nominal 1 GWe of power can be maintained by increasing the repetition rate by a factor of about 5.2, from 1.5 to 8 Hz. A higher repetition rate requires faster re-establishment of the jets after a shot, which can be accomplished in part by decreasing the jet fall height and increasing the jet flow velocity. Multiple chambers may be required.In addition, although not considered for HYLIFE-I there is undoubtedly liquid splash that must be forcibly cleared because gravity is too slow, especially at high repetition rates. Splash removal can be accomplished by either pulsed or oscillating jet flows. The cost of electricity is estimated to be 0.10 $/kW· in constant 1990 dollars, about twice that of future coal and light water reactor nuclear power. The driver beam cost is about one-half the total cost

Interaction of slow electrons with surfaces. II

International Nuclear Information System (INIS)

Komolov, S.A.; Chadderton, L.T.

1976-01-01

Total current spectroscopy (TCS) has been used to study the growth of films of gold and silver on (100) vanadium surfaces. A slow transition from TCS curves characteristic of vanadium to curves characteristic of the noble metals is observed, accompanied by an increase in the net work function - more rapid for silver than for gold. Vanadium characteristics are lost from the TCS curves for mean overlayer thicknesses > approximately 15A, and a simple analysis shows that the thickness of the surface zone from which TCS signals originate is approximately given by the electron mean free path. Observations of progressive attenuation of a characteristic vanadium feature with increasing mean thickness of overlayer permits separation into stages of nucleation and growth. There is a critical nucleus size of approximately 2A for silver and approximately 4A for gold. (Auth.)

First Imaging Observation of Standing Slow Wave in Coronal Fan Loops

International Nuclear Information System (INIS)

Pant, V.; Tiwari, A.; Banerjee, D.; Yuan, D.

2017-01-01

We observe intensity oscillations along coronal fan loops associated with the active region AR 11428. The intensity oscillations were triggered by blast waves that were generated due to X-class flares in the distant active region AR 11429. To characterize the nature of oscillations, we created time–distance maps along the fan loops and noted that the intensity oscillations at two ends of the loops were out of phase. As we move along the fan loop, the amplitude of the oscillations first decreased and then increased. The out-of-phase nature together with the amplitude variation along the loop implies that these oscillations are very likely to be standing waves. The period of the oscillations is estimated to be ∼27 minutes, damping time to be ∼45 minutes, and phase velocity projected in the plane of sky to be ∼65–83 km s"−"1. The projected phase speeds were in the range of the acoustic speed of coronal plasma at about 0.6 MK, which further indicates that these are slow waves. To the best of our knowledge, this is the first report on the existence of the standing slow waves in non-flaring fan loops.

First Imaging Observation of Standing Slow Wave in Coronal Fan Loops

Energy Technology Data Exchange (ETDEWEB)

Pant, V.; Tiwari, A.; Banerjee, D. [Indian Institute of Astrophysics, Bangalore 560 034 (India); Yuan, D. [Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen 518000 (China)

2017-09-20

We observe intensity oscillations along coronal fan loops associated with the active region AR 11428. The intensity oscillations were triggered by blast waves that were generated due to X-class flares in the distant active region AR 11429. To characterize the nature of oscillations, we created time–distance maps along the fan loops and noted that the intensity oscillations at two ends of the loops were out of phase. As we move along the fan loop, the amplitude of the oscillations first decreased and then increased. The out-of-phase nature together with the amplitude variation along the loop implies that these oscillations are very likely to be standing waves. The period of the oscillations is estimated to be ∼27 minutes, damping time to be ∼45 minutes, and phase velocity projected in the plane of sky to be ∼65–83 km s{sup −1}. The projected phase speeds were in the range of the acoustic speed of coronal plasma at about 0.6 MK, which further indicates that these are slow waves. To the best of our knowledge, this is the first report on the existence of the standing slow waves in non-flaring fan loops.

On the wall-normal velocity of the compressible boundary-layer equations

Science.gov (United States)

Pruett, C. David

1991-01-01

Numerical methods for the compressible boundary-layer equations are facilitated by transformation from the physical (x,y) plane to a computational (xi,eta) plane in which the evolution of the flow is 'slow' in the time-like xi direction. The commonly used Levy-Lees transformation results in a computationally well-behaved problem for a wide class of non-similar boundary-layer flows, but it complicates interpretation of the solution in physical space. Specifically, the transformation is inherently nonlinear, and the physical wall-normal velocity is transformed out of the problem and is not readily recovered. In light of recent research which shows mean-flow non-parallelism to significantly influence the stability of high-speed compressible flows, the contribution of the wall-normal velocity in the analysis of stability should not be routinely neglected. Conventional methods extract the wall-normal velocity in physical space from the continuity equation, using finite-difference techniques and interpolation procedures. The present spectrally-accurate method extracts the wall-normal velocity directly from the transformation itself, without interpolation, leaving the continuity equation free as a check on the quality of the solution. The present method for recovering wall-normal velocity, when used in conjunction with a highly-accurate spectral collocation method for solving the compressible boundary-layer equations, results in a discrete solution which is extraordinarily smooth and accurate, and which satisfies the continuity equation nearly to machine precision. These qualities make the method well suited to the computation of the non-parallel mean flows needed by spatial direct numerical simulations (DNS) and parabolized stability equation (PSE) approaches to the analysis of stability.

Removing Activity-Related Radial Velocity Noise to Improve Extrasolar Planet Searches

Science.gov (United States)

Saar, Steven; Lindstrom, David M. (Technical Monitor)

2004-01-01

We have made significant progress towards the proposal goals of understanding the causes and effects of magnetic activity-induced radial velocity (v_r) jitter and developing methods for correcting it. In the process, we have also made some significant discoveries in the fields of planet-induced stellar activity, planet detection methods, M dwarf convection, starspot properties, and magnetic dynamo cycles. We have obtained super high resolution (R approximately 200,000), high S / N (greater than 300) echelle study of joint line bisector and radial velocity variations using the McDonald 2-D coude. A long observing run in October 2002 in particular was quite successful (8 clear nights). We now have close to three years of data, which begins to sample a good fraction of the magnetic cycle timescales for some of our targets (e.g., kappa Ceti; P_cyc = 5.6 yrs). This will be very helpful in unraveling the complex relationships between plage and radial velocity (v-r) changes which we have uncovered. Preliminary analysis (Saar et al. 2003) of the data in hand, reveals correlations between median line bisector displacement and v_r. The correlation appears to be specific the the particular star being considered, probably since it is a function of both spectral type and rotation rate. Further analysis and interpretation will be in the context of evolving plage models and is in progress.

Implication of Broadband Dispersion Measurements in Constraining Upper Mantle Velocity Structures

Science.gov (United States)

Kuponiyi, A.; Kao, H.; Cassidy, J. F.; Darbyshire, F. A.; Dosso, S. E.; Gosselin, J. M.; Spence, G.

2017-12-01

Dispersion measurements from earthquake (EQ) data are traditionally inverted to obtain 1-D shear-wave velocity models, which provide information on deep earth structures. However, in many cases, EQ-derived dispersion measurements lack short-period information, which theoretically should provide details of shallow structures. We show that in at least some cases short-period information, such as can be obtained from ambient seismic noise (ASN) processing, must be combined with EQ dispersion measurements to properly constrain deeper (e.g. upper-mantle) structures. To verify this, synthetic dispersion data are generated using hypothetical velocity models under four scenarios: EQ only (with and without deep low-velocity layers) and combined EQ and ASN data (with and without deep low-velocity layers). The now "broadband" dispersion data are inverted using a trans-dimensional Bayesian framework with the aim of recovering the initial velocity models and assessing uncertainties. Our results show that the deep low-velocity layer could only be recovered from the inversion of the combined ASN-EQ dispersion measurements. Given this result, we proceed to describe a method for obtaining reliable broadband dispersion measurements from both ASN and EQ and show examples for real data. The implication of this study in the characterization of lithospheric and upper mantle structures, such as the Lithosphere-Asthenosphere Boundary (LAB), is also discussed.

Exercise and disease progression in multiple sclerosis: can exercise slow down the progression of multiple sclerosis?

DEFF Research Database (Denmark)

Dalgas, Ulrik; Stenager, Egon

2012-01-01

studies evaluating the effects on clinical outcome measures, (2) cross-sectional studies evaluating the relationship between fitness status and MRI findings, (3) cross-sectional and longitudinal studies evaluating the relationship between exercise/physical activity and disability/relapse rate and, finally......, (4) longitudinal exercise studies applying the experimental autoimmune encephalomyelitis (EAE) animal model of MS. Data from intervention studies evaluating disease progression by clinical measures (1) do not support a disease-modifying effect of exercise; however, MRI data (2), patient-reported data...... (3) and data from the EAE model (4) indicate a possible disease-modifying effect of exercise, but the strength of the evidence limits definite conclusions. It was concluded that some evidence supports the possibility of a disease-modifying potential of exercise (or physical activity) in MS patients...

Slow-tonic muscle fibers and their potential innervation in the turtle, Pseudemys (Trachemys) scripta elegans.

Science.gov (United States)

Callister, Robert J; Pierce, Patricia A; McDonagh, Jennifer C; Stuart, Douglas G

2005-04-01

A description is provided of the ratio of slow-tonic vs. slow- and fast-twitch fibers for five muscles in the adult turtle, Pseudemys (Trachemys) scripta elegans. The cross-sectional area of each fiber type and an estimation of the relative (weighted) cross-sectional area occupied by the different fiber types are also provided. Two hindlimb muscles (flexor digitorum longus, FDL; external gastrocnemius, EG) were selected on the basis of their suitability for future motor-unit studies. Three neck muscles (the fourth head of testo-cervicis, TeC4; the fourth head of retrahens capitus collique, RCCQ4; transversalis cervicis, TrC) were chosen for their progressively decreasing oxidative capacity. Serial sections were stained for myosin adenosine triphosphatase (ATPase), NADH-diaphorase, and alpha-glycerophosphate dehydrogenase (alpha-GPDH). Conventional fiber-type classification was then performed using indirect markers for contraction speed and oxidative (aerobic) vs. glycolytic (anaerobic) metabolism: i.e., slow oxidative (SO, including slow-twitch and possibly slow-tonic fibers), fast-twitch, oxidative-glycolytic (FOG), and fast-twitch glycolytic (Fg) fibers. Slow-tonic fibers in the SO class were then revealed by directing the monoclonal antibody, ALD-58 (raised against the slow-tonic fiber myosin heavy chain of chicken anterior latissimus dorsi), to additional muscle cross sections. All five of the tested muscles contained the four fiber types, with the ATPase-stained fibers including both slow-tonic and slow-twitch fibers. The extreme distributions of SO fibers were in the predominately glycolytic TrC vs. the predominately oxidative TeC4 muscle (TrC-SO, 9%; FOG, 20%; Fg, 71% vs. TeC4-SO, 58%: FOG, 16%; Fg, 25%). Across the five muscles, the relative prevalence of slow-tonic fibers (4-47%) paralleled that of the SO fibers (9-58%). TeC4 had the highest prevalence of slow-tonic fibers (47%). The test muscles exhibited varying degrees of regional concentration of each

Development of an optimal velocity selection method with velocity obstacle

Energy Technology Data Exchange (ETDEWEB)

Kim, Min Geuk; Oh, Jun Ho [KAIST, Daejeon (Korea, Republic of)

2015-08-15

The Velocity obstacle (VO) method is one of the most well-known methods for local path planning, allowing consideration of dynamic obstacles and unexpected obstacles. Typical VO methods separate a velocity map into a collision area and a collision-free area. A robot can avoid collisions by selecting its velocity from within the collision-free area. However, if there are numerous obstacles near a robot, the robot will have very few velocity candidates. In this paper, a method for choosing optimal velocity components using the concept of pass-time and vertical clearance is proposed for the efficient movement of a robot. The pass-time is the time required for a robot to pass by an obstacle. By generating a latticized available velocity map for a robot, each velocity component can be evaluated using a cost function that considers the pass-time and other aspects. From the output of the cost function, even a velocity component that will cause a collision in the future can be chosen as a final velocity if the pass-time is sufficiently long enough.

Midwives׳ decision making about transfers for 'slow' labour in rural New Zealand.

Science.gov (United States)

Patterson, Jean; Skinner, Joan; Foureur, Maralyn

2015-06-01

Midwives who provided Lead Maternity Care (LMC) to women in rural areas were invited to share their experiences of decision making around transfer in labour. Ethics approval was obtained from the NZ National Ethics Committee. to explore midwives׳ decision making processes when making transfer decisions for slow labour progress from rural areas to specialist care. individual and group interviews were conducted with a purposive sample of rural midwives. The recalled decision processes of the midwives were subjected to a content and thematic analysis to expose experiences in common and to highlight aspects of probabilistic (normative), heuristic (behavioural), and group decision making theory within the rural context. New Zealand. 15 midwives who provided LMC services to women in their rural areas. 'making the mind shift', 'sitting on the boundary', 'timing the transfer' and 'the community interest' emerged as key themes. The decision processes were also influenced by the woman׳s preferences and the distance and time involved in the transfer. the findings contribute insights into the challenge of making transfer decisions in rural units; particularly for otherwise well women who were experiencing slow labour progress. Knowledge of the fallibility of our heuristic decision making strategies may encourage the practitioner to step back and take a more deliberative, probabilistic view of the situation. In addition to the clinical picture, this process should include the relational and aspirational aspects for the woman, and any logistical challenges of the particular rural context. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improving the Material Response for Slow Heat of Energetic Materials

Energy Technology Data Exchange (ETDEWEB)

Nichols, A L

2010-03-08

The goal of modern high explosive slow heat cookoff modeling is to understand the level of mechanical violence. This requires understanding the coupled thermal-mechanical-chemical system that such an environment creates. Recent advances have improved our ability to predict the time to event, and we have been making progress on predicting the mechanical response. By adding surface tension to the product gas pores in the high explosive, we have been able to reduce the current model's tendency to overpressurize confinement vessels. We describe the model and demonstrate how it affects a LX-10 STEX experiment. Issues associated with current product gas equations of state are described and examined.

Positron emission tomography suggests that the rate of progression of idiopathic parkinsonism is slow

International Nuclear Information System (INIS)

Bhatt, M.H.; Snow, B.J.; Martin, W.R.; Pate, B.D.; Ruth, T.J.; Calne, D.B.

1991-01-01

The authors performed sequential positron emission tomography scans with 6-[18F]fluoro-L-dopa in 9 patients with idiopathic parkinsonism and 7 age-matched normal control subjects to compare changes in the nigrostriatal dopaminergic pathway over time. The mean interval between the scans was 3.3 years for the group with idiopathic parkinsonism and 3.9 years for the control subjects. The scans were analyzed by calculating the ratio of striatal to background radioactivity. Both groups showed statistically significant reductions of striatal uptake over the interval. The rate of decrease was almost identical in each group (p = 0.6). They infer that the usual rate of loss of integrity of the dopaminergic nigrostriatal pathway in patients with idiopathic parkinsonism is slow and the rate of change between the two groups was comparable

Velocity Building by Reflection Waveform Inversion without Cycle-skipping

KAUST Repository

Guo, Qiang

2017-05-26

Reflection waveform inversion (RWI) provides estimation of low wavenumber model components using reflections generated from a migration/demigration process. The resulting model tends to be a good initial model for FWI. In fact, the optimization images to combine the migration velocity analysis (MVA) objectives (given here by RWI) and the FWI ones. However, RWI may still encounter cycle-skipping at far offsets if the velocity model is highly inaccurate. Similar to MVA, RWI is devoted to focusing reflection data to its true image positions, yet because of the cycle skipping potential we tend to initially use only near offsets. To make the inversion procedure more robust, we introduce the extended image into our RWI. Extending the model perturbations (or image) allows us to better fit the data at larger offsets even with an inaccurate velocity. Thus, we implement a nested approach to optimize the velocity and extended image simultaneously using the objective function of RWI. We slowly reduce the extension, as the image becomes focused, to allow wavepath updates from far offsets to near as a natural progression from long wavelength updates to shorter ones. Applications on synthetic data demonstrate the effectiveness of our method without much additional cost to RWI.

Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples

Science.gov (United States)

Milsch, Harald; Priegnitz, Mike

2012-12-01

We report on changes in P and S-wave velocities and rock microstructure induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air, at ambient pressure, and temperatures between 378 and 423 K. Dehydration did not proceed homogeneously but via a reaction front moving sample inwards separating an outer highly porous rim from the remaining gypsum which, above approximately 393 (±5) K, concurrently decomposed into hemihydrate. Overall porosity was observed to continuously increase with reaction progress from approximately 2% for fully hydrated samples to 30% for completely dehydrated ones. Concurrently, P and S-wave velocities linearly decreased with porosity from 5.2 and 2.7 km/s to 1.0 and 0.7 km/s, respectively. It is concluded that a linearized empirical Raymer-type model extended by a critical porosity term and based on the respective time dependent mineral and pore volumes reasonably replicates the P and S-wave data in relation to reaction progress and porosity.

A study of the impact properties of adhesively-bonded aluminum alloy based on impact velocity

Energy Technology Data Exchange (ETDEWEB)

Gao, Teng; Cheon, Seong Sik; Cho, Jae Ung [Kongju National University, Cheonan (Korea, Republic of); Kinloch, Anthony J.; Blackman, Bamber R. K.; Sanchez, F. S. Rodriguez [Imperial College London, London (United Kingdom); Bang, Hye Jin; Lee, Sang Kyo; Cho, Chong Du [Inha University, Seoul (Korea, Republic of)

2015-02-15

In this study, an experiment and a simulation were carried out on colliding an adhesively-bonded tapered double cantilever beam (TDCB) at the impact velocities of 5 m/s, 7.5 m/s and 12.5 m/s. The analysis method of the corrected beam theory (CBT) was used to obtain the rate of energy release in the bonded area according to the crack progression, and a simulation was performed to determine the maximum strain energy during the impact analysis as a means to examine the mechanical properties of aluminium alloy. The experimental data were found to be higher than the simulation data. This is deemed to explicable by the fact that the adhesive strength was maintained even after the specimen separated in the experiment. Crack progression occurred, irrespective of the impact velocity, and high strain energy occurred at the end of the bonded region, thereby causing the strain energy to increase in the final stages. Also, the maximum load applied on the pin and the maximum strain energy in the bonded area were shown increase at higher impact velocities. The results of the experiment and simulation performed in this study are expected to serve as important data in developing a safety design for composite materials that can help prevent the progression of cracks caused by impact.

Hidden power system inflexibilities imposed by traditional unit commitment formulations

International Nuclear Information System (INIS)

Morales-España, Germán; Ramírez-Elizondo, Laura; Hobbs, Benjamin F.

2017-01-01

Highlights: • Quality and accuracy of traditional-energy- and power-based UCs are evaluated. • Real-time performance evaluation simulating “perfect” stochastic UCs. • Ideal energy-based stochastic UC formulations impose hidden system inflexibilities. • A deterministic power-based UC may outperform an ideal energy-based stochastic UC. • Power-based UC overcomes flaws of energy-based UC: lower cost and wind curtailment. - Abstract: Approximations made in traditional day-ahead unit commitment model formulations can result in suboptimal or even infeasible schedules for slow-start units and inaccurate predictions of actual costs and wind curtailment. With increasing wind penetration, these errors will become economically more significant. Here, we consider inaccuracies from three approximations: the use of hourly intervals in which energy production from each generator is modeled as being constant; the disregarding of startup and shutdown energy trajectories; and optimization based on expected wind profiles. The results of unit commitment formulations with those assumptions are compared to models that: (1) use a piecewise-linear power profiles of generation, load and wind, instead of the traditional stepwise energy profiles; (2) consider startup/shutdown trajectories; and (3) include many possible wind trajectories in a stochastic framework. The day-ahead hourly schedules of slow-start generators are then evaluated against actual wind and load profiles using a model real-time dispatch and quick-start unit commitment with a 5 min time step. We find that each simplification usually causes expected generation costs to increase by several percentage points, and results in significant understatement of expected wind curtailment and, in some cases, load interruptions. The inclusion of startup and shutdown trajectories often yielded the largest improvements in schedule performance.

Radial Velocity Survey of T Tauri Stars in Taurus-Auriga

Science.gov (United States)

Crockett, Christopher; Mahmud, N.; Huerta, M.; Prato, L.; Johns-Krull, C.; Hartigan, P.; Jaffe, D.

2009-01-01

Is the frequency of giant planet companions to young stars similar to that seen around old stars? Is the "brown dwarf desert" a product of how low-mass companion objects form, or of how they evolve? Some models indicate that both giant planets and brown dwarfs should be common at young ages within 3 AU of a primary star, but migration induced by massive disks drive brown dwarfs into the parent stars, leaving behind proportionally more giant planets. Our radial velocity survey of young stars will provide a census of the young giant planet and brown dwarf population in Taurus-Auriga. In this poster we present our progress in quantifying how spurious radial velocity signatures are caused by stellar activity and in developing models to help distinguish between companion induced and spot induced radial velocity variations. Early results stress the importance of complementary observations in both visible light and NIR. We present our technique to determine radial velocities by fitting telluric features and model stellar features to our observed spectra. Finally, we discuss ongoing observations at McDonald Observatory, KPNO, and the IRTF, and several new exoplanet host candidates.

Clearance rate of Mytilus edulis (L.) as a function of current velocity and mussel aggregation

DEFF Research Database (Denmark)

Nielsen, Pernille; Vismann, Bent

2014-01-01

by current velocities up to 1.4 m/sec, whereas experiments with 3 mussels showed that clearance of the mussels decreased progressively at current velocities greater than 0.2 m/sec, and reached 0 L/h per individual at current velocities greater than 0.6 m/sec. The constant feeding at all current velocities......The aim of the current study was to investigate the effect of water current velocities on the clearance rate of Mytilus edulis when different numbers of mussels were used in the experiments. An automatic setup, which controlled and monitored the algal concentration continually, was used to measure...... the effect of increasing current velocity (0.05-1.4 m/sec) on the M. edulis clearance rate. Clearance rate measurements were performed under constant food concentrations of 3,000 cells/mL of Rhodomonas salina on either 3 mussels or 20 mussels. We found that the clearance rate of 20 mussels was unaffected...

Velocity storage contribution to vestibular self-motion perception in healthy human subjects.

Science.gov (United States)

Bertolini, G; Ramat, S; Laurens, J; Bockisch, C J; Marti, S; Straumann, D; Palla, A

2011-01-01

Self-motion perception after a sudden stop from a sustained rotation in darkness lasts approximately as long as reflexive eye movements. We hypothesized that, after an angular velocity step, self-motion perception and reflexive eye movements are driven by the same vestibular pathways. In 16 healthy subjects (25-71 years of age), perceived rotational velocity (PRV) and the vestibulo-ocular reflex (rVOR) after sudden decelerations (90°/s(2)) from constant-velocity (90°/s) earth-vertical axis rotations were simultaneously measured (PRV reported by hand-lever turning; rVOR recorded by search coils). Subjects were upright (yaw) or 90° left-ear-down (pitch). After both yaw and pitch decelerations, PRV rose rapidly and showed a plateau before decaying. In contrast, slow-phase eye velocity (SPV) decayed immediately after the initial increase. SPV and PRV were fitted with the sum of two exponentials: one time constant accounting for the semicircular canal (SCC) dynamics and one time constant accounting for a central process, known as velocity storage mechanism (VSM). Parameters were constrained by requiring equal SCC time constant and VSM time constant for SPV and PRV. The gains weighting the two exponential functions were free to change. SPV were accurately fitted (variance-accounted-for: 0.85 ± 0.10) and PRV (variance-accounted-for: 0.86 ± 0.07), showing that SPV and PRV curve differences can be explained by a greater relative weight of VSM in PRV compared with SPV (twofold for yaw, threefold for pitch). These results support our hypothesis that self-motion perception after angular velocity steps is be driven by the same central vestibular processes as reflexive eye movements and that no additional mechanisms are required to explain the perceptual dynamics.

Differences in the Load-Velocity Profile Between 4 Bench-Press Variants.

Science.gov (United States)

García-Ramos, Amador; Pestaña-Melero, Francisco Luis; Pérez-Castilla, Alejandro; Rojas, Francisco Javier; Haff, Guy Gregory

2018-03-01

To compare the load-velocity relationship between 4 variants of the bench-press (BP) exercise. The full load-velocity relationship of 30 men was evaluated by means of an incremental loading test starting at 17 kg and progressing to the individual 1-repetition maximum (1RM) in 4 BP variants: concentric-only BP, concentric-only BP throw (BPT), eccentric-concentric BP, and eccentric-concentric BPT. A strong and fairly linear relationship between mean velocity (MV) and %1RM was observed for the 4 BP variants (r 2  > .96 for pooled data and r 2  > .98 for individual data). The MV associated with each %1RM was significantly higher in the eccentric-concentric technique than in the concentric-only technique. The only significant difference between the BP and BPT variants was the higher MV with the light to moderate loads (20-70%1RM) in the BPT using the concentric-only technique. MV was significantly and positively correlated between the 4 BP variants (r = .44-.76), which suggests that the subjects with higher velocities for each %1RM in 1 BP variant also tend to have higher velocities for each %1RM in the 3 other BP variants. These results highlight the need for obtaining specific equations for each BP variant and the existence of individual load-velocity profiles.

Recent progress of research on medicinal mushrooms, foods, and other herbal products used in traditional Chinese medicine

Directory of Open Access Journals (Sweden)

Kuo-Hsiung Lee

2012-04-01

Full Text Available This article will review selected herbal products used in traditional Chinese medicine, including medicinal mushrooms (巴西蘑菇 bā xī mó gū; Agaricus blazei, 雲芝 yún zhī; Coriolus versicolor, 靈芝 líng zhī; Ganoderma lucidum, 香蕈 xiāng xùn; shiitake, Lentinus edodes, 牛樟芝 niú zhāng zhī; Taiwanofungus camphoratus, Cordyceps (冬蟲夏草 dōng chóng xià cǎo, pomegranate (石榴 shí liú; Granati Fructus, green tea (綠茶 lǜ chá; Theae Folium Non Fermentatum, garlic (大蒜 dà suàn; Allii Sativi Bulbus, turmeric (薑黃 jiāng huáng; Curcumae Longae Rhizoma, and Artemisiae Annuae Herba (青蒿 qīng hāo; sweet wormwood. Many of the discussed herbal products have gained popularity in their uses as dietary supplements for health benefits. The review will focus on the active constituents of the herbs and their bioactivities, with emphasis on the most recent progress in research for the period of 2003 to 2011.

Ultrasonic velocity measurements- a potential sensor for intelligent processing of austenitic stainless steels

International Nuclear Information System (INIS)

Venkadesan, S.; Palanichamy, P.; Vasudevan, M.; Baldev Raj

1996-01-01

Development of sensors based on Non-Destructive Evaluation (NDE) techniques for on-line sensing of microstructure and properties requires a thorough knowledge on the relation between the sensing mechanism/measurement of an NDE technique and the microstructure. As a first step towards developing an on-line sensor for studying the dynamic microstructural changes during processing of austenitic stainless steels, ultrasonic velocity measurements have been carried out to study the microstructural changes after processing. Velocity measurements could follow the progress of annealing starting from recovery, onset and completion of recrystallization, sense the differences in the microstructure obtained after hot deformation and estimate the grain size. This paper brings out the relation between the sensing method based on ultrasonic velocity measurements and the microstructure in austenitic stainless steel. (author)

Structure of intermediate shocks and slow shocks in a magnetized plasma with heat conduction

International Nuclear Information System (INIS)

Tsai, C.L.; Wu, B.H.; Lee, L.C.

2005-01-01

The structure of slow shocks and intermediate shocks in the presence of a heat conduction parallel to the local magnetic field is simulated from the set of magnetohydrodynamic equations. This study is an extension of an earlier work [C. L. Tsai, R. H. Tsai, B. H. Wu, and L. C. Lee, Phys. Plasmas 9, 1185 (2002)], in which the effects of heat conduction are examined for the case that the tangential magnetic fields on the two side of initial current sheet are exactly antiparallel (B y =0). For the B y =0 case, a pair of slow shocks is formed as the result of evolution of the initial current sheet, and each slow shock consists of two parts: the isothermal main shock and the foreshock. In the present paper, cases with B y ≠0 are also considered, in which the evolution process leads to the presence of an additional pair of time-dependent intermediate shocks (TDISs). Across the main shock of the slow shock, jumps in plasma density, velocity, and magnetic field are significant, but the temperature is continuous. The plasma density downstream of the main shock decreases with time, while the downstream temperature increases with time, keeping the downstream pressure constant. The foreshock is featured by a smooth temperature variation and is formed due to the heat flow from downstream to upstream region. In contrast to the earlier study, the foreshock is found to reach a steady state with a constant width in the slow shock frame. In cases with B y ≠0, the plasma density and pressure increase and the magnetic field decreases across TDIS. The TDIS initially can be embedded in the slow shock's foreshock structure, and then moves out of the foreshock region. With an increasing B y , the propagation speed of foreshock leading edge tends to decrease and the foreshock reaches its steady state at an earlier time. Both the pressure and temperature downstreams of the main shock decrease with increasing B y . The results can be applied to the shock heating in the solar corona and

Acoustic radiation force impulse elastography of the kidneys: is shear wave velocity affected by tissue fibrosis or renal blood flow?

Science.gov (United States)

Asano, Kenichiro; Ogata, Ai; Tanaka, Keiko; Ide, Yoko; Sankoda, Akiko; Kawakita, Chieko; Nishikawa, Mana; Ohmori, Kazuyoshi; Kinomura, Masaru; Shimada, Noriaki; Fukushima, Masaki

2014-05-01

The aim of this study was to identify the main influencing factor of the shear wave velocity (SWV) of the kidneys measured by acoustic radiation force impulse elastography. The SWV was measured in the kidneys of 14 healthy volunteers and 319 patients with chronic kidney disease. The estimated glomerular filtration rate was calculated by the serum creatinine concentration and age. As an indicator of arteriosclerosis of large vessels, the brachial-ankle pulse wave velocity was measured in 183 patients. Compared to the degree of interobserver and intraobserver deviation, a large variance of SWV values was observed in the kidneys of the patients with chronic kidney disease. Shear wave velocity values in the right and left kidneys of each patient correlated well, with high correlation coefficients (r = 0.580-0.732). The SWV decreased concurrently with a decline in the estimated glomerular filtration rate. A low SWV was obtained in patients with a high brachial-ankle pulse wave velocity. Despite progression of renal fibrosis in the advanced stages of chronic kidney disease, these results were in contrast to findings for chronic liver disease, in which progression of hepatic fibrosis results in an increase in the SWV. Considering that a high brachial-ankle pulse wave velocity represents the progression of arteriosclerosis in the large vessels, the reduction of elasticity succeeding diminution of blood flow was suspected to be the main influencing factor of the SWV in the kidneys. This study indicates that diminution of blood flow may affect SWV values in the kidneys more than the progression of tissue fibrosis. Future studies for reducing data variance are needed for effective use of acoustic radiation force impulse elastography in patients with chronic kidney disease.

Retrospective analysis of factors affecting the progression of Chronic Renal Failure in Adult Polycystic Kidney Disease

International Nuclear Information System (INIS)

Ahmed, E.R.; Tashkandi, Muhammed A.; Nahrir, S.; Maulana, A.

2006-01-01

Autosomal dominant polycystic kidney disease (ADPKD) is the commonest congenital cystic renal disease. Factors such as hypertension, urinary tract infection, hematuria and proteinuria may effect the progression to chronic renal failure in ADPKD patients. Therapeutic interventions, such as the use of angiotensin converting enzyme inhibitors (ACEI) or diet modification, may impact the natural progression of the disease. We aim in this study to review a registry of ADPKD patients in order to compare the slow and fast progressors and identify possible predictors of progression and interventions that slow the progression of this disease. Sheffield Kidney Institute (SKI), one of the largest kidney institutes in Northern Europe, has registered a large number of ADPKD patients since 1981. SKI's computer network contains a wide range of information on these patients. We selected 94 adult polycystic patients from the SKI for retrospective analysis of factors affecting progression to chronic renal failure. Patients who doubled their s. creatinine in 3 6 months were considered fast progressors (FP), while those who doubled their s. creatinine in > 36 months were regarded as slow progressors (SP). There 70 patients in the FP group and 24 patients in the SP group. A third group of 137 patients consisted of non-progressors (NP) who ha d stable s. creatinine levels during the same period. We found that the incidence of hypertension, UTI, macroscopic and microscopic hematuria, and overt proteinuria in the FP group was higher than in SP and NP groups. Modification of some factors, such as hypertension and UTI, may decrease the rate of the deterioration of renal function. (author)

Theoretical considerations concerning the effect of relativistic velocities on the rate of biological processes.

Science.gov (United States)

Heneine, I F

1997-06-01

Theoretical considerations were advanced on the reaction rate of biological systems in a rocket accelerated at fractional levels of the velocity of light. The values of mass increase in reacting molecules and length contraction of space under these relativistic velocities attained by the hypothetical rocket were inserted in equations of the absolute reaction rate theory. The equations employed were for the frequency of collisions, and for the internal kinetic energy of molecular reactions. Results of both sets of equations indicated that reduction of reaction rates were correlated to the mass increase. This would imply a general slowing of all chemical, biochemical and biological processes taking place. A human would suffer a related decrease in metabolic rate. Contrary to what is generally accepted, the biological aging of the space traveler under velocities bearable by humans, namely under 0.50c, would follow a pace very similar to that of an observer remaining in the resting frame of reference. With increased increments of the velocity, the space traveler would display a more intense lowering of the metabolic rate, with signs and symptoms comparable to body core hypothermia. Metabolic rates at insufficient levels to maintain the vital functions would be attained at 0.70c and higher, leading swiftly to coma and death. The presence of an endocrine dysfunction such as hypothyroidism or obesity in the space traveler would aggravate the signs and symptoms. Space travel at efficient velocities would be unbearable for a warm-blooded animal.

Chaotic behavior in a relativistic electron beam interacting with a transverse slow electromagnetic wave

International Nuclear Information System (INIS)

Serbeto, A.; Alves, M.V.

1993-01-01

Using a nonlinear set of equations which describes the excitation of a purely transverse slow electromagnetic wave by a relativistic electron beam, it is shown that the system runs from chaotic behavior to a regular stable state due to crisis phenomenon and from stabilized soliton and repeated stabilized explosive solutions to a temporal chaos. These behaviors suggest that the primary mechanism for the saturation of the explosive instability is not only the cubic nonlinear frequency shift as pointed out by many authors until now. The inclusion of the velocity perturbation in the beam charge initial equilibrium state leads the system to these strange behaviors. (author)

Calculation of coupling to slow and fast waves in the LHRF from phased waveguide arrays

International Nuclear Information System (INIS)

Pinsker, R.I.; Duvall, R.E.; Fortgang, C.M.; Colestock, P.L.

1986-04-01

A previously reported algorithm for solving the problem of coupling electromagnetic energy in the LHRF from a phased array of identical rectangular waveguides to a plane-stratified, magnetized cold plasma is numerically implemented. The resulting computer codes are sufficiently general to allow for an arbitrary number of waveguides with finite dimensions in both poloidal and toroidal directions, and are thus capable of computing coupling to both slow and fast waves in the plasma. Some of the details of the implementation and the extension of the algorithm to allow study of the Fourier spectrum of slow and fast waves launched by the array are discussed. Good agreement is found with previously reported, less general work for the slow wave launching case. The effect of phasing multirow arrays in the poloidal direction is studied, and an asymmetry between phasing 'up' and 'down' is found that persists in the case where the plasma adjacent to the array is uniform. A 4 x 3 array designed to launch fast waves of high phase velocity is studied. By using the optimal poloidal phasing, low reflection coefficients (absolute value of R 2 less than or equal to 20%) are found under some not unrealistic edge plasma conditions, but most of the input power is trapped in the outermost layer of the plasma. Implications of our results for fast wave current drive experiments are discussed

A multi-time-step noise reduction method for measuring velocity statistics from particle tracking velocimetry

Science.gov (United States)

Machicoane, Nathanaël; López-Caballero, Miguel; Bourgoin, Mickael; Aliseda, Alberto; Volk, Romain

2017-10-01

We present a method to improve the accuracy of velocity measurements for fluid flow or particles immersed in it, based on a multi-time-step approach that allows for cancellation of noise in the velocity measurements. Improved velocity statistics, a critical element in turbulent flow measurements, can be computed from the combination of the velocity moments computed using standard particle tracking velocimetry (PTV) or particle image velocimetry (PIV) techniques for data sets that have been collected over different values of time intervals between images. This method produces Eulerian velocity fields and Lagrangian velocity statistics with much lower noise levels compared to standard PIV or PTV measurements, without the need of filtering and/or windowing. Particle displacement between two frames is computed for multiple different time-step values between frames in a canonical experiment of homogeneous isotropic turbulence. The second order velocity structure function of the flow is computed with the new method and compared to results from traditional measurement techniques in the literature. Increased accuracy is also demonstrated by comparing the dissipation rate of turbulent kinetic energy measured from this function against previously validated measurements.

Current Status and Future Perspective in the Globalization of Traditional Chinese Medicines

Directory of Open Access Journals (Sweden)

Wan-Ying Wu

2015-01-01

Full Text Available Globalization of traditional Chinese medicines started around 1996, which was initiated by the Chinese government. However, substantial progress was only achieved in recent years including the adoption of TCM quality monographs in the western pharmacopoeias (United States Pharmacopoeia and European Pharmacopoeia and registration in main stream drug regulatory agencies such as US Food and Drug Administration (FDA and European Medicines Agency (EMA. So far, several TCM herbal quality monographs were adopted by the United States Pharmacopoeia including Chinese Salvia, Ganoderma lucidum and Panax notoginseng, etc. Over 45 TCM quality monographs were recorded in the European Pharmacopoeia with 20 more in progress. After the successful registration of the first TCM product named Diao Xin Xue Kang as traditional medicine via the Medicines Evaluation Board of the Netherlands, several other TCM herbal products are in the registration process in several European member states. So far, there has been still not any TCM product authorized as a drug by the FDA regardless of a few TCM products in phase III or phase II clinical trials. This review summarizes the progress made in the globalization of traditional Chinese medicines in recent years and future issues in this regard.

Measurements of the toroidal plasma rotation velocity in TFTR major-radius compression experiments with auxiliary neutral beam heating

International Nuclear Information System (INIS)

Bitter, M.; Scott, S.; Wong, K.L.

1986-07-01

The time history of the central toroidal plasma rotation velocity in Tokamak Fusion Test Reactor (TFTR) experiments with auxiliary heating by neutral deuterium beam injection and major-radius compression has been measured from the Doppler shift of the emitted TiXXI-Kα line radiation. The experiments were conducted for neutral beam powers in the range from 2.1 to 3.8 MW and line-averaged densities in the range from 1.8 to 3.0 x 10 19 m -2 . The observed rotation velocity increase during compression is in agreement with results from modeling calculations which assume classical slowing-down of the injected fast deuterium ions and momentum damping at the rate established in the precompression plasma

The association of brain structure with gait velocity in older adults: a quantitative volumetric analysis of brain MRI

Energy Technology Data Exchange (ETDEWEB)

Ezzati, Ali [Albert Einstein College of Medicine of Yeshiva University, Saul B. Korey Department of Neurology, Bronx, NY (United States); Montefiore Medical Center, Department of Neurology, Bronx, NY (United States); Katz, Mindy J. [Albert Einstein College of Medicine of Yeshiva University, Saul B. Korey Department of Neurology, Bronx, NY (United States); Lipton, Michael L. [Albert Einstein College of Medicine of Yeshiva University, The Gruss Magnetic Resonance Research Center and Departments of Radiology, Psychiatry and Behavioral Sciences and the Dominick P. Purpura Department of Neuroscience, Bronx, NY (United States); Montefiore Medical Center, The Department of Radiology, Bronx, NY (United States); Lipton, Richard B. [Albert Einstein College of Medicine of Yeshiva University, Saul B. Korey Department of Neurology, Bronx, NY (United States); Albert Einstein College of Medicine of Yeshiva University, Department of Epidemiology and Population Health, Bronx, NY (United States); Verghese, Joe [Albert Einstein College of Medicine of Yeshiva University, Saul B. Korey Department of Neurology, Bronx, NY (United States); Albert Einstein College of Medicine, Division of Cognitive and Motor Aging, Bronx, NY (United States)

2015-08-15

While cortical processes play an important role in controlling locomotion, the underlying structural brain changes associated with slowing of gait in aging are not yet fully established. Our study aimed to examine the relationship between cortical gray matter volume (GM), white matter volume (WM), ventricular volume (VV), hippocampal and hippocampal subfield volumes, and gait velocity in older adults free of dementia. Gait and cognitive performance was tested in 112 community-residing adults, age 70 years and over, participating in the Einstein Aging Study. Gait velocity (cm/s) was obtained using an instrumented walkway. Volumetric MRI measures were estimated using a FreeSurfer software. We examined the cross-sectional relationship of GM, WM, VV, and hippocampal total and subfield volumes and gait velocity using linear regression models. In complementary models, the effect of memory performance on the relationship between gait velocity and regional volumes was evaluated. Slower gait velocity was associated with smaller cortical GM and total hippocampal volumes. There was no association between gait velocity and WM or VV. Among hippocampal subfields, only smaller presubiculum volume was significantly associated with decrease in gait velocity. Addition of the memory performance to the models attenuated the association between gait velocity and all volumetric measures. Our findings indicate that total GM and hippocampal volumes as well as specific hippocampal subfield volumes are inversely associated with locomotor function. These associations are probably affected by cognitive status of study population. (orig.)

The association of brain structure with gait velocity in older adults: a quantitative volumetric analysis of brain MRI

International Nuclear Information System (INIS)

Ezzati, Ali; Katz, Mindy J.; Lipton, Michael L.; Lipton, Richard B.; Verghese, Joe

2015-01-01

While cortical processes play an important role in controlling locomotion, the underlying structural brain changes associated with slowing of gait in aging are not yet fully established. Our study aimed to examine the relationship between cortical gray matter volume (GM), white matter volume (WM), ventricular volume (VV), hippocampal and hippocampal subfield volumes, and gait velocity in older adults free of dementia. Gait and cognitive performance was tested in 112 community-residing adults, age 70 years and over, participating in the Einstein Aging Study. Gait velocity (cm/s) was obtained using an instrumented walkway. Volumetric MRI measures were estimated using a FreeSurfer software. We examined the cross-sectional relationship of GM, WM, VV, and hippocampal total and subfield volumes and gait velocity using linear regression models. In complementary models, the effect of memory performance on the relationship between gait velocity and regional volumes was evaluated. Slower gait velocity was associated with smaller cortical GM and total hippocampal volumes. There was no association between gait velocity and WM or VV. Among hippocampal subfields, only smaller presubiculum volume was significantly associated with decrease in gait velocity. Addition of the memory performance to the models attenuated the association between gait velocity and all volumetric measures. Our findings indicate that total GM and hippocampal volumes as well as specific hippocampal subfield volumes are inversely associated with locomotor function. These associations are probably affected by cognitive status of study population. (orig.)

Crustal surface wave velocity structure of the east Albany-Fraser Orogen, Western Australia, from ambient noise recordings

Science.gov (United States)

Sippl, C.; Kennett, B. L. N.; Tkalčić, H.; Gessner, K.; Spaggiari, C. V.

2017-09-01

Group and phase velocity maps in the period range 2-20 s for the Proterozoic east Albany-Fraser Orogen, Western Australia, are extracted from ambient seismic noise recorded with the 70-station ALFREX array. This 2 yr temporary installation provided detailed coverage across the orogen and the edge of the Neoarchean Yilgarn Craton, a region where no passive seismic studies of this scale have occurred to date. The surface wave velocities are rather high overall (>3 km s-1 nearly everywhere), as expected for exposed Proterozoic basement rocks. No clear signature of the transition between Yilgarn Craton and Albany-Fraser Orogen is observed, but several strong anomalies corresponding to more local geological features were obtained. A prominent, NE-elongated high-velocity anomaly in the northern part of the array is coincident with a Bouguer gravity high caused by the upper crustal metamorphic rocks of the Fraser Zone. This feature disappears towards longer periods, which hints at an exclusively upper crustal origin for this anomaly. Further east, the limestones of the Cenozoic Eucla Basin are clearly imaged as a pronounced low-velocity zone at short periods, but the prevalence of low velocities to periods of ≥5 s implies that the uppermost basement in this area is likewise slow. At longer periods, slightly above-average surface wave velocities are imaged below the Eucla Basin.

Does lowering cholesterol have an impact on the progression of aortic stenosis?

DEFF Research Database (Denmark)

Greve, A.M.; Wachtell, K.

2008-01-01

reviews the pathophysiological mechanisms of calcific AS, reviews current clinical trials of statin use in aortic stenosis and reports on on-going trials, evaluating whether cholesterol lowering therapy can slow disease progression in different populations. Finally, we review if computerized tomography...

Controls on slow-moving landslides revealed by satellite and airborne InSAR

Science.gov (United States)

Handwerger, Alexander L.; Fielding, Eric J.

2017-04-01

Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. To better constrain the mechanisms that control landslide motion, we use recent SAR data collected by Copernicus Sentinel-1A/B, NASA UAVSAR, JAXA ALOS-2, and DLR TerraSAR-X to quantify the time-dependent kinematics of over 200 slow-moving landslides in the Central and Northern California Coast Ranges. These landslides are ideally suited for InSAR investigations due to their size (up to 5 km in length and 0.5 km in width), persistent downslope motion with low velocities (m/yr), and sparse vegetation. We quantify the seasonal and multi-year changes in velocity driven by changes in precipitation and find that landslide velocity varies over both timescales. Over seasonal timescales, each landslide displays a period of acceleration that occurs within weeks of the onset of seasonal rainfall suggesting that motion is governed by precipitation-induced changes in pore-water pressure. We also examine the effects of multi-year climate variations (i.e., recent historic California drought and the possible wet period that began in late 2016) on the activity of landslides. We find that the drought has led to a decrease in annual displacement over the past several years and predict that a resurgence in annual displacement will occur with an increase in annual rainfall. Lastly, we use UAVSAR data acquired at 4 different look directions to quantify 3D surface displacement of multiple landslides and invert for their subsurface geometry (i.e. basal slip surface) using recently developed 3D mass conservation techniques. The application of NASA's UAVSAR data represents a major advance from previous InSAR studies on landslides in this region and provides one of the first 3D dataset that contains

Measurement of thermal plasma jet temperature and velocity by laser light lineshape analysis

International Nuclear Information System (INIS)

Snyder, S.C.; Reynolds, L.D.

1991-01-01

Two important parameters of thermal plasma jets are kinetic or gas temperatures and flow velocity. Gas temperatures have been traditionally measured using emission spectroscopy, but this method depends on either the generally unrealistic assumption of the existence of local thermodynamic equilibrium (LTE) within the plasma, or the use of various non-LTE or partial LTE models to relate the intensity of the emission lines to the gas temperature. Plasma jet velocities have been measured using laser Doppler velocimetry on particles injected into the plasma. However, this method is intrusive and it is not known how well the particle velocities represent the gas velocity. Recently, plasma jet velocities have been measured from the Doppler shift of laser light scattered by the plasma. In this case, the Doppler shift was determined from the difference in the transmission profile of a high resolution monochromator between red shifted and blue shifted scattered light. A direct approach to measuring localized temperatures and velocities is afforded by high resolution scattered light lineshape measurements. The linewidth of laser light scattered by atoms and ions can be related to the kinetic temperature without LTE assumptions, while a shift in the peak position relative to the incident laser lineshape yields the gas velocity. We report in this paper work underway to measure gas temperatures and velocities in an argon thermal plasma jet using high resolution lineshape analysis of scattered laser light

Plants traditionally used to make Cantonese slow-cooked soup in China.

Science.gov (United States)

Liu, Yujing; Liu, Qi; Li, Ping; Xing, Deke; Hu, Huagang; Li, Lin; Hu, Xuechen; Long, Chunlin

2018-01-15

Lǎo huǒ liàng tāng (Cantonese slow-cooked soup, CSCS) is popular in Guangdong, China, and is consumed by Cantonese people worldwide as a delicious appetizer. Because CSCS serves as an important part of family healthcare, medicinal plants and plant-derived products are major components of CSCS. However, a collated record of the diverse plant species and an ethnobotanical investigation of CSCS is lacking. Because of globalization along with a renewed interest in botanical and food therapy, CSCS has attracted a growing attention in soup by industries, scientists, and consumers. This study represents the first attempt to document the plant species used for CSCS in Guangdong, China, and the associated ethnomedical function of plants, including their local names, part(s) used, flavors, nature, preparation before cooking, habitats, and conservation status. In 2014-2017, participatory approaches, open-ended conversations, and semi-structured interviews were conducted with 63 local people and 48 soup restaurant owners (111 interviews) to better understand the biocultural context of CSCS, emphasizing ethnobotanical uses of plants in Guangdong Province, China. Product samples and voucher specimens were collected for taxonomic identification. Mention Index (QI), frequency of use index (FUI), and economic index (EI) were adopted to evaluate the significance of each plant in the food supply. A total of 97 plant species belonging to 46 families and 90 genera were recorded as having been used in CSCS in the study area. Recorded menus consisted of one or several plant species, with each one used for different purposes. They were classified into 11 functions, with clearing heat being the most common medicinal function. Of the 97 species, 19 grew only in the wild, 8 species were both wild and cultivated, and 70 species were cultivated. Roots and fruits were the most commonly used plant parts in the preparation of CSCS. According to the national evaluation criteria, six of these

Sport-Specific Training Targeting the Proximal Segments and Throwing Velocity in Collegiate Throwing Athletes

Science.gov (United States)

Palmer, Thomas; Uhl, Timothy L.; Howell, Dana; Hewett, Timothy E.; Viele, Kert; Mattacola, Carl G.

2015-01-01

Context The ability to generate, absorb, and transmit forces through the proximal segments of the pelvis, spine, and trunk has been proposed to influence sport performance, yet traditional training techniques targeting the proximal segments have had limited success improving sport-specific performance. Objective To investigate the effects of a traditional endurance-training program and a sport-specific power-training program targeting the muscles that support the proximal segments and throwing velocity. Design Randomized controlled clinical trial. Setting University research laboratory and gymnasium. Patients or Other Participants A total of 46 (age = 20 ± 1.3 years, height = 175.7 ± 8.7 cm) healthy National Collegiate Athletic Association Division III female softball (n = 17) and male baseball (n = 29) players. Intervention(s) Blocked stratification for sex and position was used to randomly assign participants to 1 of 2 training groups for 7 weeks: a traditional endurance-training group (ET group; n = 21) or a power-stability–training group (PS group; n = 25). Mean Outcome Measure(s) The change score in peak throwing velocity (km/h) normalized for body weight (BW; kilograms) and change score in tests that challenge the muscles of the proximal segments normalized for BW (kilograms). We used 2-tailed independent-samples t tests to compare differences between the change scores. Results The peak throwing velocity (ET group = 0.01 ± 0.1 km/h/kg of BW, PS group = 0.08 ± 0.03 km/h/kg of BW; P < .001) and muscle power outputs for the chop (ET group = 0.22 ± 0.91 W/kg of BW, PS group = 1.3 ± 0.91 W/kg of BW; P < .001) and lift (ET group = 0.59 ± 0.67 W/kg of BW, PS group = 1.4 ± 0.87 W/kg of BW; P < .001) tests were higher at postintervention in the PT than in the ET group. Conclusions An improvement in throwing velocity occurred simultaneously with measures of muscular endurance and power after a sport-specific training regimen targeting the proximal segments

The influence of slip velocity and temperature on permeability during and after high-velocity fault slip

Science.gov (United States)

Tanikawa, W.; Mukoyoshi, H.; Tadai, O.; Hirose, T.; Lin, W.

2011-12-01

Fluid transport properties in fault zones play an important role in dynamic processes during large earthquakes. If the permeability in a fault zone is low, high pore-fluid pressures caused by thermal pressurization (Sibson, 1973) or shear-induced compaction (Blanpied et al., 1992) can lead to an apparent reduction of fault strength. Changes in porosity and permeability of fault rocks within a fault zone during earthquakes and the subsequent progressive recovery of these properties may have a large influence on earthquake recurrence (Sleep and Blanpied, 1992). A rotary shear apparatus was used to investigate changes of fluid transport properties in a fault zone by real-time measurement of gas flow rates during and after shearing of hollow sandstone and granite cylinders at various slip rates. Our apparatus measures permeability parallel to the slip plane in both the slip zone and wall rocks. In all cases, permeability decreased rapidly with an increase of friction, but recovered soon after slip, reaching a steady state within several tens of minutes. The rate of reduction of permeability increased with increasing slip velocity. Permeability did not recover to pre-slip levels after low-velocity tests but recovered to exceed them after high-velocity tests. Frictional heating of gases at the slip surface increased gas viscosity, which increased gas flow rate to produce an apparent permeability increase. The irreversible permeability changes of the low-velocity tests were caused by gouge formation due to wearing and smoothing of the slip surface. The increase of permeability after high-velocity tests was caused by mesoscale fracturing in response to rapid temperature rise. Changes of pore fluid viscosity contributed more to changes of flow rate than did permeability changes caused by shear deformation, although test results from different rocks and pore fluids might be different. References Blanpied, M.L., Lockner, D.A., Byerlee, J.D., 1992. An earthquake mechanism

Rainbow particle imaging velocimetry for dense 3D fluid velocity imaging

KAUST Repository

Xiong, Jinhui

2017-07-21

Despite significant recent progress, dense, time-resolved imaging of complex, non-stationary 3D flow velocities remains an elusive goal. In this work we tackle this problem by extending an established 2D method, Particle Imaging Velocimetry, to three dimensions by encoding depth into color. The encoding is achieved by illuminating the flow volume with a continuum of light planes (a

Research progress on high altitude retinopathy and application of Traditional Chinese Medicine

Directory of Open Access Journals (Sweden)

Hai-Xiang Huang

2014-11-01

Full Text Available High altitude retinopathy(HARrefers to the body which can't adapt to the hypobaric hypoxia environment at high altitude leading to retinal diseases, which typically manifested as retinal hemorrhages, optic disc edema and cotton wool spots. With the development of high altitude medicine, HAR become a hot topic of eye research in recent years. New researches show a significantly higher incidence of HAR, and HAR has a close contact with acute mountain sickness, high altitude cerebral edema and high altitude pulmonary edema. A further study in pathogenesis and prevention measures of HAR will promote the prevention of altitude sickness. Traditional Chinese Medicine has achieved good effects in the prevention of altitude sickness, but the effect and mechanism of herbs on HAR has not been reported. Through read and summarize the relevant literatures and reports, the author will give an overview of the research advances on HAR's pathogenesis and application of Traditional Chinese Medicine.

Progress in reforming chemical engineering education.

Science.gov (United States)

Wankat, Phillip C

2013-01-01

Three successful historical reforms of chemical engineering education were the triumph of chemical engineering over industrial chemistry, the engineering science revolution, and Engineering Criteria 2000. Current attempts to change teaching methods have relied heavily on dissemination of the results of engineering-education research that show superior student learning with active learning methods. Although slow dissemination of education research results is probably a contributing cause to the slowness of reform, two other causes are likely much more significant. First, teaching is the primary interest of only approximately one-half of engineering faculty. Second, the vast majority of engineering faculty have no training in teaching, but trained professors are on average better teachers. Significant progress in reform will occur if organizations with leverage-National Science Foundation, through CAREER grants, and the Engineering Accreditation Commission of ABET-use that leverage to require faculty to be trained in pedagogy.

Slow movement execution in event-related potentials (P300).

Science.gov (United States)

Naruse, Kumi; Sakuma, Haruo; Hirai, Takane

2002-02-01

We examined whether slow movement execution has an effect on cognitive and information processing by measuring the P300 component. 8 subjects performed a continuous slow forearm rotational movement using 2 task speeds. Slow (a 30-50% decrease from the subject's Preferred speed) and Very Slow (a 60-80% decrease). The mean coefficient of variation for rotation speed under Very Slow was higher than that under Slow, showing that the subjects found it difficult to perform the Very Slow task smoothly. The EEG score of alpha-1 (8-10 Hz) under Slow Condition was increased significantly more than under the Preferred Condition; however, the increase under Very Slow was small when compared with Preferred. After performing the task. P300 latency under Very Slow increased significantly as compared to that at pretask. Further, P300 amplitude decreased tinder both speed conditions when compared to that at pretask, and a significant decrease was seen under the Slow Condition at Fz, whereas the decrease under the Very Slow Condition was small. These differences indicated that a more complicated neural composition and an increase in subjects' attention might have been involved when the task was performed under the Very Slow Condition. We concluded that slow movement execution may have an influence on cognitive function and may depend on the percentage of decrease from the Preferred speed of the individual.

Variable Resistance Training Promotes Greater Strength and Power Adaptations Than Traditional Resistance Training in Elite Youth Rugby League Players.

Science.gov (United States)

Rivière, Maxence; Louit, Loic; Strokosch, Alasdair; Seitz, Laurent B

2017-04-01

Rivière, M, Louit, L, Strokosch, A, and Seitz, LB. Variable resistance training promotes greater strength and power adaptations than traditional resistance training in elite youth rugby league players. J Strength Cond Res 31(4): 947-955, 2017-The purpose of this study was to examine the strength, velocity, and power adaptations in youth rugby league players in response to a variable resistance training (VRT) or traditional free-weight resistance training (TRAD) intervention. Sixteen elite youth players were assigned to a VRT or TRAD group and completed 2 weekly upper- and lower-body strength and power sessions for 6 weeks. Training programs were identical except that the VRT group trained the bench press exercise with 20% of the prescribed load coming from elastic bands. Bench press 1 repetition maximum (1RM) and bench press mean velocity and power at 35, 45, 65, 75, and 85% of 1RM were measured before and after the training intervention, and the magnitude of the changes was determined using effect sizes (ESs). The VRT group experienced larger increases in both absolute (ES = 0.46 vs. 0.20) and relative (ES = 0.41 vs. 0.19) bench press 1RM. Similar results were observed for mean velocity as well as both absolute and relative mean power at 35, 45, 65, 75, and 85% of 1RM. Furthermore, both groups experienced large gains in both velocity and power in the heavier loads but small improvements in the lighter loads. The improvements in both velocity and power against the heavier loads were larger for the VRT group, whereas smaller differences existed between the 2 groups in the lighter loads. Variable resistance training using elastic bands may offer a greater training stimulus than traditional free-weight resistance training to improve upper-body strength, velocity, and power in elite youth rugby league players.

Using UAVSAR Interferometry to Quantify the Geometry and Sediment Flux of Slow-moving Landslides in the Eel River Catchment, Northern California

Science.gov (United States)

Handwerger, A. L.; Huang, M. H.; Booth, A. M.; Fielding, E. J.

2017-12-01

Slow-moving, deep-seated landslides are highly erosive features that can remain active for periods of decades to centuries, playing a major role in landscape evolution. In the Eel River catchment, Northern California, slow-moving landslides are the primary contributor of sediment to the channel network, delivering >50% of the regional sediment flux despite occupying mass conservation techniques to 1) invert for landslide thickness and 2) solve for landslide rheology (i.e. depth-averaged velocity), which enables us to better constrain both volume and sediment flux. Our preliminary results indicate that the landslide thickness is highly variable with changes up to tens of meters along the landslide body. We also find that the landslides have a power law rheology with a plug-flow vertical velocity profile. Estimates of sediment flux contributed by individual landslides ranges from 103 to 104 m3/yr. The application of UAVSAR data represents a major advance from previous InSAR studies in this region and provides one of the first datasets containing 3D displacement measurements for multiple landslides occurring under nearly identical environmental conditions. Future work is aimed at using these subsurface and kinematic data to calculate landslide erosion rates and regional sediment flux and to better understand the controls on landslide dynamics over short- and long-timescales.

Coexistence and transition between shear zones in slow granular flows.

Science.gov (United States)

Moosavi, Robabeh; Shaebani, M Reza; Maleki, Maniya; Török, János; Wolf, Dietrich E; Losert, Wolfgang

2013-10-04

We report experiments on slow granular flows in a split-bottom Couette cell that show novel strain localization features. Nontrivial flow profiles have been observed which are shown to be the consequence of simultaneous formation of shear zones in the bulk and at the boundaries. The fluctuating band model based on a minimization principle can be fitted to the experiments over a large variation of morphology and filling height with one single fit parameter, the relative friction coefficient μ(rel) between wall and bulk. The possibility of multiple shear zone formation is controlled by μ(rel). Moreover, we observe that the symmetry of an initial state, with coexisting shear zones at both side walls, breaks spontaneously below a threshold value of the shear velocity. A dynamical transition between two asymmetric flow states happens over a characteristic time scale which depends on the shear strength.

Relating seismicity to the velocity structure of the San Andreas Fault near Parkfield, CA

Science.gov (United States)

Lippoldt, Rachel; Porritt, Robert W.; Sammis, Charles G.

2017-06-01

The central section of the San Andreas Fault (SAF) displays a range of seismic phenomena including normal earthquakes, low-frequency earthquakes (LFE), repeating microearthquakes (REQ) and aseismic creep. Although many lines of evidence suggest that LFEs are tied to the presence of fluids, their geological setting is still poorly understood. Here, we map the seismic velocity structures associated with LFEs beneath the central SAF using surface wave tomography from ambient seismic noise to provide constraints on the physical conditions that control LFE occurrence. Fault perpendicular sections show that the SAF, as revealed by lateral contrasts in relative velocities, is contiguous to depths of 50 km and appears to be relatively localized at depths between about 15 and 30 km. This is consistent with the hypothesis that LFEs are shear-slip events on a deep extension of the SAF. We find that along strike variations in seismic behaviour correspond to changes in the seismic structure, which support proposed connections between fluids and seismicity. LFEs and REQs occur within low-velocity structures, suggesting that the presence of fluids, weaker minerals, or hydrous phase minerals may play an important role in the generation of slow-slip phenomena.

Auditory velocity discrimination in the horizontal plane at very high velocities.

Science.gov (United States)

Frissen, Ilja; Féron, François-Xavier; Guastavino, Catherine

2014-10-01

We determined velocity discrimination thresholds and Weber fractions for sounds revolving around the listener at very high velocities. Sounds used were a broadband white noise and two harmonic sounds with fundamental frequencies of 330 Hz and 1760 Hz. Experiment 1 used velocities ranging between 288°/s and 720°/s in an acoustically treated room and Experiment 2 used velocities between 288°/s and 576°/s in a highly reverberant hall. A third experiment addressed potential confounds in the first two experiments. The results show that people can reliably discriminate velocity at very high velocities and that both thresholds and Weber fractions decrease as velocity increases. These results violate Weber's law but are consistent with the empirical trend observed in the literature. While thresholds for the noise and 330 Hz harmonic stimulus were similar, those for the 1760 Hz harmonic stimulus were substantially higher. There were no reliable differences in velocity discrimination between the two acoustical environments, suggesting that auditory motion perception at high velocities is robust against the effects of reverberation. Copyright © 2014 Elsevier B.V. All rights reserved.

The effect of angiotensin-converting-enzyme inhibitors on progression of advanced polycystic kidney disease

DEFF Research Database (Denmark)

Jafar, Tazeen H; Stark, Paul C; Schmid, Christopher H

2005-01-01

BACKGROUND: It is not known whether angiotensin-converting-enzyme (ACE) inhibitors slow the progression of polycystic kidney disease (PKD). We performed a patient-level meta-analysis to compare the effect of antihypertensive regimens, including ACE inhibitors, to those without ACE inhibitors...... of doubling of baseline serum creatinine or onset of kidney failure). We also performed multivariable linear regression and Cox proportional hazards analyses. Based on previous findings, we searched for interactions between the treatment effect (effect of ACE inhibitors vs. controls) and baseline urine......%) in the ACE inhibitor group and 30 patients (41%) in the control group (P= 0.17). ACE inhibitors had a greater effect on lowering urine protein excretion and slowing kidney disease progression in patients with higher levels of baseline urine protein excretion (interaction P

ECTRIMS/ACTRIMS 2017: Closing in on neurorepair in progressive multiple sclerosis.

Science.gov (United States)

Kremer, David; Küry, Patrick; Hartung, Hans-Peter

2018-04-01

While there is now a multitude of potent medications for relapsing-remitting multiple sclerosis (RRMS), effective therapies targeting neurodegeneration in progressive multiple sclerosis types are still lacking. Stimulation of neurorepair in this disease remains a pathogenetically defined treatment goal. However, therapeutic progress is slowed by the still inadequate tool set to capture "regeneration/repair" in MS and to define appropriate outcomes in clinical trials. In this review, we discuss studies investigating promising regenerative agents for progressive MS which were recently presented during the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS)/Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) 2017 meeting in Paris.

Development of a robotic evaluation system for the ability of proprioceptive sensation in slow hand motion.

Science.gov (United States)

Tanaka, Yoshiyuki; Mizoe, Genki; Kawaguchi, Tomohiro

2015-01-01

This paper proposes a simple diagnostic methodology for checking the ability of proprioceptive/kinesthetic sensation by using a robotic device. The perception ability of virtual frictional forces is examined in operations of the robotic device by the hand at a uniform slow velocity along the virtual straight/circular path. Experimental results by healthy subjects demonstrate that percentage of correct answers for the designed perceptual tests changes in the motion direction as well as the arm configuration and the HFM (human force manipulability) measure. It can be supposed that the proposed methodology can be applied into the early detection of neuromuscular/neurological disorders.

Uremic Solutes in Chronic Kidney Disease and Their Role in Progression.

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Jan A J G van den Brand

Full Text Available To date, over 150 possible uremic solutes have been listed, but their role in the progression of CKD is largely unknown. Here, the association between a selected panel of uremic solutes and progression in CKD patients was investigated.Patients from the MASTERPLAN study, a randomized controlled trial in CKD patients with a creatinine clearance between 20 and 70 ml/min per 1.73m2, were selected based on their rate of eGFR decline during the first five years of follow-up. They were categorized as rapid (decline >5 ml/min per year or slow progressors. Concentrations of eleven uremic solutes were obtained at baseline and after one year of follow-up. Logistic regression was used to compare the odds for rapid to slow progression by uremic solute concentrations at baseline. Variability in uremic solute levels was assessed using scatter plots, and limits of variability were calculated.In total, 40 rapidly and 40 slowly progressing patients were included. Uremic solutes were elevated in all patients compared to reference values for healthy persons. The serum levels of uremic solutes were not associated with rapid progression. Moreover, we observed substantial variability in solute levels over time.Elevated concentrations of uremic solutes measured in this study did not explain differences in rate of eGFR decline in CKD patients, possibly due to lack of power as a result of the small sample size, substantial between patient variability, and variability in solute concentrations over time. The etiology of intra-individual variation in uremic solute levels remains to be elucidated.

Uremic Solutes in Chronic Kidney Disease and Their Role in Progression.

Science.gov (United States)

van den Brand, Jan A J G; Mutsaers, Henricus A M; van Zuilen, Arjan D; Blankestijn, Peter J; van den Broek, Petra H; Russel, Frans G M; Masereeuw, Rosalinde; Wetzels, Jack F M

2016-01-01

To date, over 150 possible uremic solutes have been listed, but their role in the progression of CKD is largely unknown. Here, the association between a selected panel of uremic solutes and progression in CKD patients was investigated. Patients from the MASTERPLAN study, a randomized controlled trial in CKD patients with a creatinine clearance between 20 and 70 ml/min per 1.73m2, were selected based on their rate of eGFR decline during the first five years of follow-up. They were categorized as rapid (decline >5 ml/min per year) or slow progressors. Concentrations of eleven uremic solutes were obtained at baseline and after one year of follow-up. Logistic regression was used to compare the odds for rapid to slow progression by uremic solute concentrations at baseline. Variability in uremic solute levels was assessed using scatter plots, and limits of variability were calculated. In total, 40 rapidly and 40 slowly progressing patients were included. Uremic solutes were elevated in all patients compared to reference values for healthy persons. The serum levels of uremic solutes were not associated with rapid progression. Moreover, we observed substantial variability in solute levels over time. Elevated concentrations of uremic solutes measured in this study did not explain differences in rate of eGFR decline in CKD patients, possibly due to lack of power as a result of the small sample size, substantial between patient variability, and variability in solute concentrations over time. The etiology of intra-individual variation in uremic solute levels remains to be elucidated.

Recent progress on the traditional Chinese medicines that regulate the blood

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Hsin-Yi Hung

2016-04-01

Full Text Available In traditional Chinese medicine, the herbs that regulate blood play a vital role. Here, nine herbs including Typhae Pollen, Notoginseng Root, Common Bletilla Tuber, India Madder Root and Rhizome, Chinese Arborvitae Twig, Lignum Dalbergiae Oderiferae, Chuanxiong Rhizoma, Corydalis Tuber, and Motherwort Herb were selected and reviewed for their recent studies on anti-tumor, anti-inflammatory and cardiovascular effects. Besides, the analytical methods developed to qualify or quantify the active compounds of the herbs are also summarized.

Dynamically tunable slow light based on plasmon induced transparency in disk resonators coupled MDM waveguide system

International Nuclear Information System (INIS)

Han, Xu; Wang, Tao; Liu, Bo; He, Yu; Tang, Jian; Li, Xiaoming

2015-01-01

Ultrafast and low-power dynamically tunable single channel and multichannel slow light based on plasmon induced transparencies (PITs) in disk resonators coupled to a metal-dielectric-metal (MDM) waveguide system with a nonlinear optical Kerr medium is investigated both numerically and analytically. A coupled-mode theory (CMT) is introduced to analyze this dynamically tunable single channel slow light structure. Multichannel slow light is realized in this plasmonic waveguide structure based on a bright–dark mode coupling mechanism. In order to reduce the pump intensity and obtain ultrafast response time, the traditional nonlinear Kerr material is replaced by monolayer graphene. It is found that the magnitude of the single PIT window can be controlled between 0.08 and 0.48, while the corresponding group index is controlled between 14.5 and 2.0 by dynamically decreasing pump intensity from 11.7 to 4.4 MW cm −2 . Moreover, the phase shift multiplication effect is found in this structure. This work paves a new way towards the realization of highly integrated optical circuits and networks, especially for wavelength-selective, all-optical storage and nonlinear devices. (paper)

Application of Planar Broadband Slow-Wave Systems

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Edvardas Metlevskis

2012-04-01

Full Text Available Different types of planar broadband slow-wave systems are used for designing microwave devices. The papers published by Lithuanian scientists analyze and investigate the models of helical and meander slow-wave systems. The article carefully examines the applications of meander slow-wave systems and presents the areas where similar systems, e.g. mobile devices, RFID, wireless technologies are used and reviewed nowadays. The paper also focuses on the examples of the papers discussing antennas, filters and couplers that contain designed and fabricated meander slow-wave systems.Article in Lithuanian

The 2011 Tohoku-oki Earthquake related to a large velocity gradient within the Pacific plate

Science.gov (United States)

Matsubara, Makoto; Obara, Kazushige

2015-04-01

We conduct seismic tomography using arrival time data picked by the high sensitivity seismograph network (Hi-net) operated by National Research Institute for Earth Science and Disaster Prevention (NIED). We used earthquakes off the coast outside the seismic network around the source region of the 2011 Tohoku-oki Earthquake with the centroid depth estimated from moment tensor inversion by NIED F-net (broadband seismograph network) as well as earthquakes within the seismic network determined by Hi-net. The target region, 20-48N and 120-148E, covers the Japanese Islands from Hokkaido to Okinawa. A total of manually picked 4,622,346 P-wave and 3,062,846 S-wave arrival times for 100,733 earthquakes recorded at 1,212 stations from October 2000 to August 2009 is available for use in the tomographic method. In the final iteration, we estimate the P-wave slowness at 458,234 nodes and the S-wave slowness at 347,037 nodes. The inversion reduces the root mean square of the P-wave traveltime residual from 0.455 s to 0.187 s and that of the S-wave data from 0.692 s to 0.228 s after eight iterations (Matsubara and Obara, 2011). Centroid depths are determined using a Green's function approach (Okada et al., 2004) such as in NIED F-net. For the events distant from the seismic network, the centroid depth is more reliable than that determined by NIED Hi-net, since there are no stations above the hypocenter. We determine the upper boundary of the Pacific plate based on the velocity structure and earthquake hypocentral distribution. The upper boundary of the low-velocity (low-V) oceanic crust corresponds to the plate boundary where thrust earthquakes are expected to occur. Where we do not observe low-V oceanic crust, we determine the upper boundary of the upper layer of the double seismic zone within high-V Pacific plate. We assume the depth at the Japan Trench as 7 km. We can investigate the velocity structure within the Pacific plate such as 10 km beneath the plate boundary since the

Prevalence and Pattern of Traditional and Complementary Alternative Medicine Use in Diabetic Patients in Dubai, UAE

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Usama ALAlami

2017-12-01

Full Text Available Background: The current study explored the prevalence and pattern of traditional and complementary alternative medicine (TCAM use, its perceived benefits and possible impact on health outcomes amongst diabetics in Dubai, UAE. Objectives: Diabetes is highly prevalent in the UAE, with diabetics potentially not complying with the prescribed conventional medicines, or preferring to use of traditional and complementary alternative medicines. The current study therefore sheds light on these two areas. Methods: A descriptive cross-sectional pilot study was conducted in 4 healthcare facilities in Dubai using quantitative data collection methods. Using a systematic random sampling method, 145 diabetic participants completed a self-reported questionnaire. Measures in the questionnaire included traditional and complementary alternative medicine use, and perceived benefits. SPSS version 21 was used for result analysis. Chi-square test was used to confirm significance amongst various groups. Results: Amongst 145 diabetic participants recruited, 66.9% were female, and 57.9% had undergraduate degree. Majority of participants (95.2% had type II diabetes. Participants age was between 20 to 79 years. The prevalence of TCAM use amongst the participants was 21.4%, with the majority of users being female (27.8%. TCAM use was more common amongst housewives (28.6%. None of the TCAM users had the intervention prescribed by a health specialist, and the majority (51.6% used it for the purpose of slowing the progression of the disease. More than half (58.1% of TCAM users reported receiving the desired effect, and 77.4% used TCAM in combination with the prescribed conventional medicine. Conclusion: The current study confirmed the un-prescribed use of TCAM amongst participants in Dubai, UAE. Further studies are required to elaborate on the interaction between TCAM and prescribed conventional medicines.

Research on the Application of Traditional Embroidery Technology in Modern Jewelry Creation

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Min Li

2017-10-01

Full Text Available Tradition and modernity are the eternal topics of art, especially in the age of information.Efficient mechanical production methods to improve the traditional jewelry production process, which achieved the demand for mass production of jewelry.However, with the development of society and the progress of science and technology,  many traditional arts and crafts are lost.From the traditional culture, this paper analyzes the work of embroidery jewelry by studying the traditional Chinese embroidery culture and technique, summarizes the traditional embroidery technology and modern jewelry design techniques combined approach to guide the creative practice.On the basis of studying the theoretical method of combining traditional embroidery technology with modern jewelry, this paper focuses on the application of traditional embroidery techniques in jewelry creation, inspire the potential of traditional craft, to provide reference for modern jewelry design rich Chinese characteristics and attract the attention of  Chinese jewelry industry and inherit the traditional arts.

Slow, stopped and stored light

International Nuclear Information System (INIS)

Welch, G.; Scully, M.

2005-01-01

Light that can been slowed to walking pace could have applications in telecommunications, optical storage and quantum computing. Whether we use it to estimate how far away a thunderstorm is, or simply take it for granted that we can have a conversation with someone on the other side of the world, we all know that light travels extremely fast. Indeed, special relativity teaches us that nothing in the universe can ever move faster than the speed of light in a vacuum: 299 792 458 ms sup - sup 1. However, there is no such limitation on how slowly light can travel. For the last few years, researchers have been routinely slowing light to just a few metres per second, and have recently even stopped it dead in its tracks so that it can be stored for future use. Slow-light has considerable popular appeal, deriving perhaps from the importance of the speed of light in relativity and cosmology. If everyday objects such as cars or people can travel faster than 'slow' light, for example, then it might appear that relativistic effects could be observed at very low speeds. Although this is not the case, slow light nonetheless promises to play an important role in optical technology because it allows light to be delayed for any period of time desired. This could lead to all-optical routers that would increase the bandwidth of the Internet, and applications in optical data storage, quantum information and even radar. (U.K.)

miRNA targeted signaling pathway in the early stage of denervated fast and slow muscle atrophy

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Gang Li

2016-01-01

Full Text Available Denervation often results in skeletal muscle atrophy. Different mechanisms seem to be involved in the determination between denervated slow and fast skeletal muscle atrophy. At the epigenetic level, miRNAs are thought to be highly involved in the pathophysiological progress of denervated muscles. We used miRNA microarrays to determine miRNA expression profiles from a typical slow muscle (soleus muscle and a typical fast muscle (tibialis anterior muscle at an early denervation stage in a rat model. Results showed that miR-206, miR-195, miR-23a, and miR-30e might be key factors in the transformation process from slow to fast muscle in denervated slow muscles. Additionally, certain miRNA molecules (miR-214, miR-221, miR-222, miR-152, miR-320, and Let-7e could be key regulatory factors in the denervated atrophy process involved in fast muscle. Analysis of signaling pathway networks revealed the miRNA molecules that were responsible for regulating certain signaling pathways, which were the final targets (e.g., p38 MAPK pathway; Pax3/Pax7 regulates Utrophin and follistatin by HDAC4; IGF1/PI3K/Akt/mTOR pathway regulates atrogin-1 and MuRF1 expression via FoxO phosphorylation. Our results provide a better understanding of the mechanisms of denervated skeletal muscle pathophysiology.

Time limit and VO2 slow component at intensities corresponding to VO2max in swimmers.

Science.gov (United States)

Fernandes, R J; Cardoso, C S; Soares, S M; Ascensão, A; Colaço, P J; Vilas-Boas, J P

2003-11-01

The purpose of this study was to measure, in swimming pool conditions and with high level swimmers, the time to exhaustion at the minimum velocity that elicits maximal oxygen consumption (TLim at vVO(2)max), and the corresponding VO(2) slow component (O(2)SC). The vVO(2)max was determined through an intermittent incremental test (n = 15). Forty-eight hours later, TLim was assessed using an all-out swim at vVO(2)max until exhaustion. VO(2) was measured through direct oximetry and the swimming velocity was controlled using a visual light-pacer. Blood lactate concentrations and heart rate values were also measured. Mean VO(2)max for the incremental test was 5.09 +/- 0.53 l/min and the corresponding vVO(2)max was 1.46 +/- 0.06 m/s. Mean TLim value was 260.20 +/- 60.73 s and it was inversely correlated with the velocity of anaerobic threshold (r = -0.54, p energy cost of the respiratory muscles (r = 0.51), for p swimming pool, in high level swimmers performing at vVO(2)max, and that higher TLim seems to correspond to higher expected O(2)SC amplitude. These findings seem to bring new data with application in middle distance swimming.

Exploring cultural drivers for wildlife trade via an ethnoprimatological approach: a case study of slender and slow lorises (Loris and Nycticebus) in South and Southeast Asia.

Science.gov (United States)

Nekaris, K A I; Shepherd, C R; Starr, C R; Nijman, V

2010-09-01

Illegal and unsustainable trade in wildlife is a major conservation challenge. For Asian primates, economic and cultural traditions, and increased forest access mean that trade may have become detrimental for certain species. Slow and slender lorises (Nycticebus and Loris) are primates particularly prevalent in trade, determined until now by focused counts of lorises in regional markets. Here, we use international trade statistics and a participant-observer approach to assess culturally specific drivers for trade in lorises in South and Southeast Asia, to provide a broader context to help mitigate this practice. Analysis of international records for the last 30 years revealed that live animal trade was more prevalent than trade in body parts (slow lorises, 86.4%; slender lorises, 91.4%), with Laos, Cambodia, and Thailand the largest exporters. We then examine drivers of international and domestic trade based on long-term data from 1994-2009 in Sri Lanka, Cambodia, and Indonesia. We show that slender lorises are important in Sri Lankan folklore, but their use as pets and for traditional medicine is rare. Trade in Bengal slow and pygmy lorises in Cambodia for use in traditional medicines, a practice with deeply historical roots, is widespread. Despite its own set of myths about the magical and curative properties of lorises, trade in Javan, Bornean, and greater slow lorises in Indonesia is largely for pets. Conservation practices in Asia are often generalized and linked with the region's major religions and economies. We show here that, in the case of wildlife trade, culturally specific patterns are evident among different ethnic groups, even within a country. Revealing such patterns is the foundation for developing conservation management plans for each species. We suggest some participatory methods for each country that may aid in this process. 2010 Wiley-Liss, Inc.

Superconducting RF for Low-Velocity and Intermediate-Velocity Beams

CERN Document Server

Grimm, Terry L

2005-01-01

Existing superconducting radio frequency (SRF) linacs are used to accelerate ions (protons through uranium) with velocities less than about 15% the speed of light, or electrons with velocities approximately equal to the speed of light. In the last ten years, prototype SRF cavities have completely covered the remaining range of velocities. They have demonstrated that SRF linacs will be capable of accelerating electrons from rest up to the speed of light, and ions from less than 1% up to the speed of light. When the Spallation Neutron Source is operational, SRF ion linacs will have covered the full range of velocities except for v/c ~ 0.15 to v/c ~ 0.5. A number of proposed projects (RIA, EURISOL) would span the latter range of velocities. Future SRF developments will have to address the trade-offs associated with a number of issues, including high gradient operation, longitudinal and transverse acceptance, microphonics, Lorentz detuning, operating temperature, cryogenic load, number of gaps or cells per cavity...

Effect of core stability training on throwing velocity in female handball players.

Science.gov (United States)

Saeterbakken, Atle H; van den Tillaar, Roland; Seiler, Stephen

2011-03-01

The purpose was to study the effect of a sling exercise training (SET)-based core stability program on maximal throwing velocity among female handball players. Twenty-four female high-school handball players (16.6 ± 0.3 years, 63 ± 6 kg, and 169 ± 7 cm) participated and were initially divided into a SET training group (n = 14) and a control group (CON, n = 10). Both groups performed their regular handball training for 6 weeks. In addition, twice a week, the SET group performed a progressive core stability-training program consisting of 6 unstable closed kinetic chain exercises. Maximal throwing velocity was measured before and after the training period using photocells. Maximal throwing velocity significantly increased 4.9% from 17.9 ± 0.5 to 18.8 ± 0.4 m·s in the SET group after the training period (p core stability training using unstable, closed kinetic chain movements can significantly improve maximal throwing velocity. A stronger and more stable lumbopelvic-hip complex may contribute to higher rotational velocity in multisegmental movements. Strength coaches can incorporate exercises exposing the joints for destabilization force during training in closed kinetic chain exercises. This may encourage an effective neuromuscular pattern and increase force production and can improve a highly specific performance task such as throwing.

Critical velocities in He II for independently varied superfluid and normal fluid velocities

International Nuclear Information System (INIS)

Baehr, M.L.

1984-01-01

Experiments were performed to measure the critical velocity in pure superflow and compare to the theoretical prediction; to measure the first critical velocity for independently varied superfluid and normal fluid velocities; and to investigate the propagation of the second critical velocity from the thermal counterflow line through the V/sub n/,-V/sub s/ quadrant. The experimental apparatus employed a thermal counterflow heater to adjust the normal fluid velocity, a fountain pump to vary the superfluid velocity, and a level sensing capacitor to measure the superfluid velocity. The results of the pure superfluid critical velocity measurements indicate that this velocity is temperature independent contrary to Schwarz's theory. It was found that the first critical velocity for independently varied V/sub n/ and V/sub s/ could be described by a linear function of V/sub n/ and was otherwise temperature independent. It was found that the second critical velocity could only be distinguished near the thermal counterflow line

Hierarchical cluster analysis of progression patterns in open-angle glaucoma patients with medical treatment.

Science.gov (United States)

Bae, Hyoung Won; Rho, Seungsoo; Lee, Hye Sun; Lee, Naeun; Hong, Samin; Seong, Gong Je; Sung, Kyung Rim; Kim, Chan Yun

2014-04-29

To classify medically treated open-angle glaucoma (OAG) by the pattern of progression using hierarchical cluster analysis, and to determine OAG progression characteristics by comparing clusters. Ninety-five eyes of 95 OAG patients who received medical treatment, and who had undergone visual field (VF) testing at least once per year for 5 or more years. OAG was classified into subgroups using hierarchical cluster analysis based on the following five variables: baseline mean deviation (MD), baseline visual field index (VFI), MD slope, VFI slope, and Glaucoma Progression Analysis (GPA) printout. After that, other parameters were compared between clusters. Two clusters were made after a hierarchical cluster analysis. Cluster 1 showed -4.06 ± 2.43 dB baseline MD, 92.58% ± 6.27% baseline VFI, -0.28 ± 0.38 dB per year MD slope, -0.52% ± 0.81% per year VFI slope, and all "no progression" cases in GPA printout, whereas cluster 2 showed -8.68 ± 3.81 baseline MD, 77.54 ± 12.98 baseline VFI, -0.72 ± 0.55 MD slope, -2.22 ± 1.89 VFI slope, and seven "possible" and four "likely" progression cases in GPA printout. There were no significant differences in age, sex, mean IOP, central corneal thickness, and axial length between clusters. However, cluster 2 included more high-tension glaucoma patients and used a greater number of antiglaucoma eye drops significantly compared with cluster 1. Hierarchical cluster analysis of progression patterns divided OAG into slow and fast progression groups, evidenced by assessing the parameters of glaucomatous progression in VF testing. In the fast progression group, the prevalence of high-tension glaucoma was greater and the number of antiglaucoma medications administered was increased versus the slow progression group. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Traditional Malian Solid Foods Made from Sorghum and Millet Have Markedly Slower Gastric Emptying than Rice, Potato, or Pasta

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Fatimata Cisse

2018-01-01

Full Text Available From anecdotal evidence that traditional African sorghum and millet foods are filling and provide sustained energy, we hypothesized that gastric emptying rates of sorghum and millet foods are slow, particularly compared to non-traditional starchy foods (white rice, potato, wheat pasta. A human trial to study gastric emptying of staple foods eaten in Bamako, Mali was conducted using a carbon-13 (13C-labelled octanoic acid breath test for gastric emptying, and subjective pre-test and satiety response questionnaires. Fourteen healthy volunteers in Bamako participated in a crossover design to test eight starchy staples. A second validation study was done one year later in Bamako with six volunteers to correct for endogenous 13C differences in the starches from different sources. In both trials, traditional sorghum and millet foods (thick porridges and millet couscous had gastric half-emptying times about twice as long as rice, potato, or pasta (p < 0.0001. There were only minor changes due to the 13C correction. Pre-test assessment of millet couscous and rice ranked them as more filling and aligned well with postprandial hunger rankings, suggesting that a preconceived idea of rice being highly satiating may have influenced subjective satiety scoring. Traditional African sorghum and millet foods, whether viscous in the form of a thick porridge or as non-viscous couscous, had distinctly slow gastric emptying, in contrast to the faster emptying of non-traditional starchy foods, which are popular among West African urban consumers.

Political determinants of progress in the MDGs in Sub-Saharan Africa.

Science.gov (United States)

Atti, Emma; Gulis, Gabriel

2017-11-01

Sub-Saharan Africa (SSA) lagged furthest behind in achieving targets for the millennium development goals (MDG). We investigate the hypothesis that its slow progress is influenced by political factors. Longitudinal data on three health MDG indicators: under-five mortality, maternal mortality and HIV prevalence rates were collated from 1990 to 2012 in 48 countries. Countries were grouped into geo-political and eco-political groups. Groupings were based on conflict trends in geographical regions and the International Monetary Fund's classification of SSA countries based on gross national income and development assistance respectively. Cumulative progress in each group was derived and main effects tested using ANOVA. Correlation analysis was conducted between political variables - POLITY 2, fragile state index (FSI), voter turnout rates, civil liberty scores (CLS) and the health variables. Our results suggest a significant main effect of eco-political and geo-political groups on some of the health variables. Political conflict as measured by FSI and political participation as measured by CLS were stronger predictors of slow progress in reducing under-five mortality rates and maternal mortality ratios. Our findings highlight the need for further research on political determinants of mortality in SSA. Cohesive effort should focus on strengthening countries' political, economic and social capacities in order to achieve sustainable goals beyond 2015.

Experimental demonstration of spinor slow light

Science.gov (United States)

Lee, Meng-Jung; Ruseckas, Julius; Lee, Chin-Yuan; Kudriašov, Viačeslav; Chang, Kao-Fang; Cho, Hung-Wen; JuzeliÅ«nas, Gediminas; Yu, Ite A.

2016-03-01

Over the last decade there has been a continuing interest in slow and stored light based on the electromagnetically induced transparency (EIT) effect, because of their potential applications in quantum information manipulation. However, previous experimental works all dealt with the single-component slow light which cannot be employed as a qubit. In this work, we report the first experimental demonstration of two-component or spinor slow light (SSL) using a double tripod (DT) atom-light coupling scheme. The oscillations between the two components, similar to the Rabi oscillation of a two-level system or a qubit, were observed. Single-photon SSL can be considered as two-color qubits. We experimentally demonstrated a possible application of the DT scheme as quantum memory and quantum rotator for the two-color qubits. This work opens up a new direction in the slow light research.

Mechanism and application of a newly developed pressure casting process: horizontal squeeze casting

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Li Peijie

2014-07-01

Full Text Available Compared to traditional high-pressure die casting (HPDC, horizontal squeeze casting (HSC is a more promising way to fabricate high-integrity castings, owing to a reduced number of gas and shrinkage porosities produced in the casting. In this paper, the differences between HSC and HPDC are assessed, through which it is shown that the cavity filling velocity and the size of the gating system to be the most notable differences. Equipment development and related applications are also reviewed. Furthermore, numerical simulation is used to analyze the three fundamental characteristics of HSC: slow cavity filling, squeeze feeding and slow sleeve filling. From this, a selection principle is given based on the three related critical casting parameters: cavity filling velocity, gate size and sleeve filling velocity. Finally, two specific applications of HSC are introduced, and the future direction of HSC development is discussed.

Measuring the Angular Velocity of a Propeller with Video Camera Using Electronic Rolling Shutter

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Yipeng Zhao

2018-01-01

Full Text Available Noncontact measurement for rotational motion has advantages over the traditional method which measures rotational motion by means of installing some devices on the object, such as a rotary encoder. Cameras can be employed as remote monitoring or inspecting sensors to measure the angular velocity of a propeller because of their commonplace availability, simplicity, and potentially low cost. A defect of the measurement with cameras is to process the massive data generated by cameras. In order to reduce the collected data from the camera, a camera using ERS (electronic rolling shutter is applied to measure angular velocities which are higher than the speed of the camera. The effect of rolling shutter can induce geometric distortion in the image, when the propeller rotates during capturing an image. In order to reveal the relationship between the angular velocity and the image distortion, a rotation model has been established. The proposed method was applied to measure the angular velocities of the two-blade propeller and the multiblade propeller. The experimental results showed that this method could detect the angular velocities which were higher than the camera speed, and the accuracy was acceptable.

Reciprocity in the electronic stopping of slow ions in matter

International Nuclear Information System (INIS)

Sigmund, P.

2008-01-01

The principle of reciprocity, i.e., the invariance of the inelastic excitation in ion-atom collisions against interchange of projectile and target, has been applied to the electronic stopping cross section of low-velocity ions and tested empirically on ion-target combinations supported by a more or less adequate amount of experimental data. Reciprocity is well obeyed (within ∼10%) for many systems studied, and deviations exceeding ∼20% are exceptional. Systematic deviations such as gas-solid or metal-insulator differences have been looked for but not identified on the present basis. A direct consequence of reciprocity is the equivalence of Z 1 with Z 2 structure for random slowing down. This feature is reasonably well supported empirically for ion-target combinations involving carbon, nitrogen, aluminium and argon. Reciprocity may be utilized as a criterion to reject questionable experimental data. In cases where a certain stopping cross section has not been or cannot be measured, the stopping cross section for the inverted system may be available and serve as a first estimate. It is suggested to build in reciprocity as a fundamental requirement into empirical interpolation schemes directed at the stopping of low-velocity ions. Examination of the SRIM and MSTAR codes reveals cases where reciprocity is obeyed accurately, but deviations of up to a factor of two are common. In case of heavy ions such as gold, electronic stopping cross sections predicted by SRIM are asserted to be almost an order of magnitude too high. (authors)

Reciprocity in the electronic stopping of slow ions in matter

Science.gov (United States)

Sigmund, P.

2008-04-01

The principle of reciprocity, i.e., the invariance of the inelastic excitation in ion-atom collisions against interchange of projectile and target, has been applied to the electronic stopping cross section of low-velocity ions and tested empirically on ion-target combinations supported by a more or less adequate amount of experimental data. Reciprocity is well obeyed (within ~10%) for many systems studied, and deviations exceeding ~20% are exceptional. Systematic deviations such as gas-solid or metal-insulator differences have been looked for but not identified on the present basis. A direct consequence of reciprocity is the equivalence of Z1 with Z2 structure for random slowing down. This feature is reasonably well supported empirically for ion-target combinations involving carbon, nitrogen, aluminium and argon. Reciprocity may be utilized as a criterion to reject questionable experimental data. In cases where a certain stopping cross section has not been or cannot be measured, the stopping cross section for the inverted system may be available and serve as a first estimate. It is suggested to build in reciprocity as a fundamental requirement into empirical interpolation schemes directed at the stopping of low-velocity ions. Examination of the SRIM and MSTAR codes reveals cases where reciprocity is obeyed accurately, but deviations of up to a factor of two are common. In case of heavy ions such as gold, electronic stopping cross sections predicted by SRIM are asserted to be almost an order of magnitude too high.

Mean Velocity vs. Mean Propulsive Velocity vs. Peak Velocity: Which Variable Determines Bench Press Relative Load With Higher Reliability?

Science.gov (United States)

García-Ramos, Amador; Pestaña-Melero, Francisco L; Pérez-Castilla, Alejandro; Rojas, Francisco J; Gregory Haff, G

2018-05-01

García-Ramos, A, Pestaña-Melero, FL, Pérez-Castilla, A, Rojas, FJ, and Haff, GG. Mean velocity vs. mean propulsive velocity vs. peak velocity: which variable determines bench press relative load with higher reliability? J Strength Cond Res 32(5): 1273-1279, 2018-This study aimed to compare between 3 velocity variables (mean velocity [MV], mean propulsive velocity [MPV], and peak velocity [PV]): (a) the linearity of the load-velocity relationship, (b) the accuracy of general regression equations to predict relative load (%1RM), and (c) the between-session reliability of the velocity attained at each percentage of the 1-repetition maximum (%1RM). The full load-velocity relationship of 30 men was evaluated by means of linear regression models in the concentric-only and eccentric-concentric bench press throw (BPT) variants performed with a Smith machine. The 2 sessions of each BPT variant were performed within the same week separated by 48-72 hours. The main findings were as follows: (a) the MV showed the strongest linearity of the load-velocity relationship (median r = 0.989 for concentric-only BPT and 0.993 for eccentric-concentric BPT), followed by MPV (median r = 0.983 for concentric-only BPT and 0.980 for eccentric-concentric BPT), and finally PV (median r = 0.974 for concentric-only BPT and 0.969 for eccentric-concentric BPT); (b) the accuracy of the general regression equations to predict relative load (%1RM) from movement velocity was higher for MV (SEE = 3.80-4.76%1RM) than for MPV (SEE = 4.91-5.56%1RM) and PV (SEE = 5.36-5.77%1RM); and (c) the PV showed the lowest within-subjects coefficient of variation (3.50%-3.87%), followed by MV (4.05%-4.93%), and finally MPV (5.11%-6.03%). Taken together, these results suggest that the MV could be the most appropriate variable for monitoring the relative load (%1RM) in the BPT exercise performed in a Smith machine.

A system and method for online high-resolution mapping of gastric slow-wave activity.

Science.gov (United States)

Bull, Simon H; O'Grady, Gregory; Du, Peng; Cheng, Leo K

2014-11-01

High-resolution (HR) mapping employs multielectrode arrays to achieve spatially detailed analyses of propagating bioelectrical events. A major current limitation is that spatial analyses must currently be performed "off-line" (after experiments), compromising timely recording feedback and restricting experimental interventions. These problems motivated development of a system and method for "online" HR mapping. HR gastric recordings were acquired and streamed to a novel software client. Algorithms were devised to filter data, identify slow-wave events, eliminate corrupt channels, and cluster activation events. A graphical user interface animated data and plotted electrograms and maps. Results were compared against off-line methods. The online system analyzed 256-channel serosal recordings with no unexpected system terminations with a mean delay 18 s. Activation time marking sensitivity was 0.92; positive predictive value was 0.93. Abnormal slow-wave patterns including conduction blocks, ectopic pacemaking, and colliding wave fronts were reliably identified. Compared to traditional analysis methods, online mapping had comparable results with equivalent coverage of 90% of electrodes, average RMS errors of less than 1 s, and CC of activation maps of 0.99. Accurate slow-wave mapping was achieved in near real-time, enabling monitoring of recording quality and experimental interventions targeted to dysrhythmic onset. This work also advances the translation of HR mapping toward real-time clinical application.

The effect of cluster loading on force, velocity, and power during ballistic jump squat training.

Science.gov (United States)

Hansen, Keir T; Cronin, John B; Newton, Michael J

2011-12-01

The purpose of this study was to investigate the effect of set structure, in terms of repetition work:rest ratios on force, velocity, and power during jump squat training. Twenty professional and semiprofessional rugby players performed training sessions comprising four sets of 6 repetitions of a jump squat using four different set configurations. The first involved a traditional configuration (TR) of 4 × 6 repetitions with 3 min of rest between sets, the second (C1) 4 × 6 × singles (1 repetition) with 12 s of rest between repetitions, the third (C2) 4 × 3 × doubles (2 repetitions) with 30 s of rest between pairs, and the third (C3) 4 × 2 × triples (3 repetitions) with 60 s of rest between triples. A spreadsheet for the analysis of controlled trials that calculated the P-value, and percent difference and Cohen's effect size from log-transformed data was used to investigate differences in repetition force, velocity, and power profiles among configurations. Peak power was significantly lower (P < .05) for the TR condition when compared with C1 and C3 for repetition 4, and all cluster configurations for repetitions 5 and 6. Peak velocity was significantly lower (P < .05) for the TR condition compared with C3 at repetition 4, significantly lower compared with C2 and C3 at repetition 5, and significantly lower compared with all cluster conditions for repetition 6. Providing inter-repetition rest during a traditional set of six repetitions can attenuate decreases in power and velocity of movement through the set.

Progressive multifocal leukoencephalopathy limited to the brain stem

Energy Technology Data Exchange (ETDEWEB)

Kastrup, O.; Maschke, M.; Diener, H.C. [Neurologische Universitaetsklinik, University of Essen (Germany); Wanke, I. [Department of Neuroradiology, University of Essen (Germany)

2002-03-01

Progressive multifocal leukoencephalopathy (PML) is a subacute demyelinating slow-virus encephalitis caused by the JC polyomavirus in 2-5% of patients with AIDS. MRI typically shows multiple lesions in the cerebral hemispheres. We present a rare case of rapidly evolving and lethal PML with a severe bulbar syndrome and spastic tetraparesis in a patient with AIDS. MRI showed high-signal lesions on T2-weighted images confined to the brain stem, extending from the medulla oblongata to the midbrain. JC virus polymerase chain reaction in cerebrospinal fluid was positive, and neuropathology showed the findings of PML. This case was also notable because of the rapid progression despite improved immune status with antiretroviral therapy. (orig.)

Slow-light effects in photonic crystal membrane lasers

DEFF Research Database (Denmark)

Xue, Weiqi; Yu, Yi; Ottaviano, Luisa

2015-01-01

In this paper, we present a systematic investigation of photonic crystal cavity laser operating in the slow-light regime. The dependence of lasing threshold on the effect of slow-light will be particularly highlighted.......In this paper, we present a systematic investigation of photonic crystal cavity laser operating in the slow-light regime. The dependence of lasing threshold on the effect of slow-light will be particularly highlighted....

Slow potentials in a melody recognition task.

Science.gov (United States)

Verleger, R; Schellberg, D

1990-01-01

In a previous study, slow negative shifts were found in the EEG of subjects listening to well-known melodies. The two experiments reported here were designed to investigate the variables to which these slow potentials are related. In the first experiment, two opposite hypotheses were tested: The slow shifts might express subjects' acquaintance with the melodies or, on the contrary, the effort invested to identify them. To this end, some of the melodies were presented in the rhythms of other melodies to make recognition more difficult. Further, melodies rated as very well-known and as very unknown were analysed separately. However, the slow shifts were not affected by these experimental variations. Therefore in the second experiment, on the one hand the purely physical parameters intensity and duration were varied, but this variation had no impact on the slow shifts either. On the other hand, recognition was made more difficult by monotonously repeating the pitch of the 4th tone for the rest of some melodies. The slow negative shifts were enhanced with these monotonous melodies. This enhancement supports the "effort" hypothesis. Accordingly, the ofter shifts obtained in both experiments might likewise reflect effort. But since the task was not demanding, it is suggested that these constant shifts reflect the effort invested for coping with the entire underarousing situation rather than with the task. Frequently, slow eye movements occurred in the same time range as the slow potentials, resulting in EOG potentials spreading to the EEG recording sites. Yet results did not change substantially when the EEG recordings were corrected for the influence of EOG potentials.

VELOCITY FIELD OF COMPRESSIBLE MAGNETOHYDRODYNAMIC TURBULENCE: WAVELET DECOMPOSITION AND MODE SCALINGS

International Nuclear Information System (INIS)

Kowal, Grzegorz; Lazarian, A.

2010-01-01

We study compressible magnetohydrodynamic turbulence, which holds the key to many astrophysical processes, including star formation and cosmic-ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid, we use wavelet decomposition of the turbulent velocity field into Alfven, slow, and fast modes, which presents an extension of the Cho and Lazarian decomposition approach based on Fourier transforms. The wavelets allow us to follow the variations of the local direction of the magnetic field and therefore improve the quality of the decomposition compared to the Fourier transforms, which are done in the mean field reference frame. For each resulting component, we calculate the spectra and two-point statistics such as longitudinal and transverse structure functions as well as higher order intermittency statistics. In addition, we perform a Helmholtz- Hodge decomposition of the velocity field into incompressible and compressible parts and analyze these components. We find that the turbulence intermittency is different for different components, and we show that the intermittency statistics depend on whether the phenomenon was studied in the global reference frame related to the mean magnetic field or in the frame defined by the local magnetic field. The dependencies of the measures we obtained are different for different components of the velocity; for instance, we show that while the Alfven mode intermittency changes marginally with the Mach number, the intermittency of the fast mode is substantially affected by the change.

Premotor neurons encode torsional eye velocity during smooth-pursuit eye movements

Science.gov (United States)

Angelaki, Dora E.; Dickman, J. David

2003-01-01

Responses to horizontal and vertical ocular pursuit and head and body rotation in multiple planes were recorded in eye movement-sensitive neurons in the rostral vestibular nuclei (VN) of two rhesus monkeys. When tested during pursuit through primary eye position, the majority of the cells preferred either horizontal or vertical target motion. During pursuit of targets that moved horizontally at different vertical eccentricities or vertically at different horizontal eccentricities, eye angular velocity has been shown to include a torsional component the amplitude of which is proportional to half the gaze angle ("half-angle rule" of Listing's law). Approximately half of the neurons, the majority of which were characterized as "vertical" during pursuit through primary position, exhibited significant changes in their response gain and/or phase as a function of gaze eccentricity during pursuit, as if they were also sensitive to torsional eye velocity. Multiple linear regression analysis revealed a significant contribution of torsional eye movement sensitivity to the responsiveness of the cells. These findings suggest that many VN neurons encode three-dimensional angular velocity, rather than the two-dimensional derivative of eye position, during smooth-pursuit eye movements. Although no clear clustering of pursuit preferred-direction vectors along the semicircular canal axes was observed, the sensitivity of VN neurons to torsional eye movements might reflect a preservation of similar premotor coding of visual and vestibular-driven slow eye movements for both lateral-eyed and foveate species.

THE REFINED SHOCK VELOCITY OF THE X-RAY FILAMENTS IN THE RCW 86 NORTHEAST RIM

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, Hiroya; Castro, Daniel; Williams, Brian J.; Petre, Robert [NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Katsuda, Satoru [Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Lopez, Laura A. [Department of Astronomy and Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States); Slane, Patrick O.; Smith, Randall K., E-mail: hiroya.yamaguchi@nasa.gov [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2016-03-20

A precise measurement of shock velocities is crucial for constraining the mechanism and efficiency of cosmic-ray (CR) acceleration at supernova remnant (SNR) shock fronts. The northeastern rim of the SNR RCW 86 is thought to be a particularly efficient CR acceleration site, owing to the recent result in which an extremely high shock velocity of ∼6000 km s{sup −1} was claimed. Here, we revisit the same SNR rim with the Chandra X-ray Observatory, 11 years after the first observation. This longer baseline than previously available allows us to determine a more accurate proper motion of the nonthermal X-ray filament, revealing a much lower velocity of 3000 ± 340 km s{sup −1} (and even slower at a brighter region). Although the value has dropped to one-half of that from the previous X-ray measurement, it is still higher than the mean velocity of the Hα filaments in this region (∼1200 km s{sup −1}). This discrepancy implies that the filaments bright in nonthermal X-rays and Hα emission trace different velocity components, and thus a CR pressure constrained by combining the X-ray kinematics and the Hα spectroscopy can easily be overestimated. We also measure the proper motion of the thermal X-ray filament immediately to the south of the nonthermal one. The inferred velocity (720 ± 360 km s{sup −1}) is significantly lower than that of the nonthermal filament, suggesting the presence of denser ambient material, possibly a wall formed by a wind from the progenitor, which has drastically slowed down the shock.

Traditional Chinese medicines and Alzheimer's disease.

Science.gov (United States)

Wu, Tzong-Yuan; Chen, Chih-Ping; Chen, Chip-Ping; Jinn, Tzyy-Rong

2011-06-01

Traditional Chinese medicines have been widely investigated for the treatment of Alzheimer's disease (AD) because none of the current therapies-either the cholinesterase inhibitors or antagonist of N-methyl-d-aspartate receptors-has profound effects on halting the progression of AD. In recent years, scientists have isolated many active compounds from herbs, which can alleviate dementia and neurodegenerative syndrome with fewer side effects than conventional drugs and, thus, are regarded as promising drug candidates for AD therapy. In this review, we summarize the latest research progress on six herbs for AD therapy-Huperzia serrata, Amaryllidaceae family, Ginkgo biloba, Uncaria rhynchophylla, Polygala tenuifolia, and Salvia officinalis-and focus on the analysis of their active components and possible mechanisms of pharmacological actions on AD. Copyright © 2011. Published by Elsevier B.V.

Traditional Tibetan Physical Culture as Seen from A Culturological Perspective

Institute of Scientific and Technical Information of China (English)

DING LINGHUI

2011-01-01

@@ Traditional Tibetan physical culture is an important part of Tibetan culture.It has rich cultural connotations, its own characteristics, and inherent development laws.From prehistoric times to the Kingdom of Tufan to the Qing period, physical culture promoted civilization and progress in Tibet.

Velocity loss as an indicator of neuromuscular fatigue during resistance training.

Science.gov (United States)

Sánchez-Medina, Luis; González-Badillo, Juan José

2011-09-01

This study aimed to analyze the acute mechanical and metabolic response to resistance exercise protocols (REP) differing in the number of repetitions (R) performed in each set (S) with respect to the maximum predicted number (P). Over 21 exercise sessions separated by 48-72 h, 18 strength-trained males (10 in bench press (BP) and 8 in squat (SQ)) performed 1) a progressive test for one-repetition maximum (1RM) and load-velocity profile determination, 2) tests of maximal number of repetitions to failure (12RM, 10RM, 8RM, 6RM, and 4RM), and 3) 15 REP (S × R[P]: 3 × 6[12], 3 × 8[12], 3 × 10[12], 3 × 12[12], 3 × 6[10], 3 × 8[10], 3 × 10[10], 3 × 4[8], 3 × 6[8], 3 × 8[8], 3 × 3[6], 3 × 4[6], 3 × 6[6], 3 × 2[4], 3 × 4[4]), with 5-min interset rests. Kinematic data were registered by a linear velocity transducer. Blood lactate and ammonia were measured before and after exercise. Mean repetition velocity loss after three sets, loss of velocity pre-post exercise against the 1-m·s load, and countermovement jump height loss (SQ group) were significant for all REP and were highly correlated to each other (r = 0.91-0.97). Velocity loss was significantly greater for BP compared with SQ and strongly correlated to peak postexercise lactate (r = 0.93-0.97) for both SQ and BP. Unlike lactate, ammonia showed a curvilinear response to loss of velocity, only increasing above resting levels when R was at least two repetitions higher than 50% of P. Velocity loss and metabolic stress clearly differs when manipulating the number of repetitions actually performed in each training set. The high correlations found between mechanical (velocity and countermovement jump height losses) and metabolic (lactate, ammonia) measures of fatigue support the validity of using velocity loss to objectively quantify neuromuscular fatigue during resistance training.

Precision medicine and traditional chinese medicine of dialogue

Directory of Open Access Journals (Sweden)

Lou Xin

2017-01-01

Full Text Available The precision medicine is more precise individualized medicine, based on the patient’s genes or physiological to formulate the specific treatment plan, for the realization of individualized treatment of various diseases to provide valuable information.But with the progress of modern science and technology, modern medicine dependence on medical instruments are too serious, traditional ways are gradually forgotten.If the machine depends on the instrument test results too serious which don’t combined with the actual diagnosis, the cause of misdiagnosis, so we should pay attention to the overall analysis of diseases and systematic diagnosis and examination, use of the overall treatment concept traced back to find the cause of Traditional Chinese Medicine, finally decide to select a best treatment plan.We should use the dialectical attitude to look at the precise medical. Not blindly requirements according to the road of precision medicine of Traditional Chinese Medicine to go, to shine in himself field, form of self characteristic of Traditional Chinese Medicine.Can learn some of the advantages of accurate concept, the good and rejecting the bad, hope the Traditional Chinese Medicine in the modern environment more walk more far.

Application of railgun principle to high-velocity hydrogen pellet injection for magnetic fusion reactor refueling: Technical progress report

International Nuclear Information System (INIS)

Kim, K.

1986-01-01

A detailed experimental study successfully demonstrates the acceleration of frozen hydrogen pellets by means of a fuseless two-stage electromagnetic railgun system. This system consists of a pneumatic hydrogen pellet injector, which freezes and pneumatically pre-accelerates (with high-pressure helium as the propellant gas) cylindrical 1.6-mm-dia by 2.15-mm-long hydrogen pellets, and a 60-cm-long, 1.6-mm-dia circular-bore electromagnetic railgun. The pellet is introduced into the railgun by means of a coupling piece, and a plasma-arc armature is created from the propellant gas by means of a very unique, fuseless, arc-initiation scheme. Railgun-accelerated hydrogen pellet velocities in excess of 1.6 km/s are achieved from pneumatically accelerated injection velocities of 800 m/s. Streak-camera and current-probe data show that the plasma-arc armature moves at a velocity proportional to the railgun current, I. Insight to this I-dependence is gained through the use of streak photography and current probes for varying bore geometries and gas pressures

Diffraction imaging and velocity analysis using oriented velocity continuation

KAUST Repository

Decker, Luke

2014-08-05

We perform seismic diffraction imaging and velocity analysis by separating diffractions from specular reflections and decomposing them into slope components. We image slope components using extrapolation in migration velocity in time-space-slope coordinates. The extrapolation is described by a convection-type partial differential equation and implemented efficiently in the Fourier domain. Synthetic and field data experiments show that the proposed algorithm is able to detect accurate time-migration velocities by automatically measuring the flatness of events in dip-angle gathers.

Effect of Core Training on Male Handball Players' Throwing Velocity.

Science.gov (United States)

Manchado, Carmen; García-Ruiz, José; Cortell-Tormo, Juan Manuel; Tortosa-Martínez, Juan

2017-02-01

In handball, throwing velocity is considered to be one of the essential factors in achieving the ultimate aim of scoring a goal. The objective of the present study was to analyze the effect of a core training program on throwing velocity in 30 handball players (age 18.7 ± 3.4 years, body height 179.3 ± 7.0 cm, body mass 78.9 ± 7.7 kg), 16 of whom were in the junior category and 14 of whom were in the senior category. The 30 players were randomly divided into two groups, the control group (n = 15) and the experimental group (n = 15). For a period of ten weeks, both groups attended their regular handball training sessions (four per week), but in addition, the experimental group participated in a program specifically aimed at progressively strengthening the lumbo-pelvic region and consisting of seven exercises performed after the general warm-up in each regular session. Pre- and post-tests were carried out to analyze each player's throwing velocity from different throwing positions and thus assess the effects of this specific training program. Statistically significant differences (p ≤ 0.05) in throwing velocity were observed between the experimental group, which presented a percentage improvement of 4.5%, and the control group, which did not show any improvement. The results seem to indicate that an increase in the strength and stability of the lumbo-pelvic region can contribute to an improvement in the kinetic chain of the specific movement of throwing in handball, thus, increasing throwing velocity.

Effect of Core Training on Male Handball Players’ Throwing Velocity

Science.gov (United States)

García-Ruiz, José; Cortell-Tormo, Juan Manuel; Tortosa-Martínez, Juan

2017-01-01

Abstract In handball, throwing velocity is considered to be one of the essential factors in achieving the ultimate aim of scoring a goal. The objective of the present study was to analyze the effect of a core training program on throwing velocity in 30 handball players (age 18.7 ± 3.4 years, body height 179.3 ± 7.0 cm, body mass 78.9 ± 7.7 kg), 16 of whom were in the junior category and 14 of whom were in the senior category. The 30 players were randomly divided into two groups, the control group (n = 15) and the experimental group (n = 15). For a period of ten weeks, both groups attended their regular handball training sessions (four per week), but in addition, the experimental group participated in a program specifically aimed at progressively strengthening the lumbo-pelvic region and consisting of seven exercises performed after the general warm-up in each regular session. Pre- and post-tests were carried out to analyze each player’s throwing velocity from different throwing positions and thus assess the effects of this specific training program. Statistically significant differences (p ≤ 0.05) in throwing velocity were observed between the experimental group, which presented a percentage improvement of 4.5%, and the control group, which did not show any improvement. The results seem to indicate that an increase in the strength and stability of the lumbo-pelvic region can contribute to an improvement in the kinetic chain of the specific movement of throwing in handball, thus, increasing throwing velocity. PMID:28469756

Pulsar slow-down epochs

International Nuclear Information System (INIS)

Heintzmann, H.; Novello, M.

1981-01-01

The relative importance of magnetospheric currents and low frequency waves for pulsar braking is assessed and a model is developed which tries to account for the available pulsar timing data under the unifying aspect that all pulsars have equal masses and magnetic moments and are born as rapid rotators. Four epochs of slow-down are distinguished which are dominated by different braking mechanisms. According to the model no direct relationship exists between 'slow-down age' and true age of a pulsar and leads to a pulsar birth-rate of one event per hundred years. (Author) [pt

A comparison of height and weight velocity as a part of the composite endpoint in pediatric HIV.

Science.gov (United States)

Benjamin, Daniel K; Miller, Wiliam C; Benjamin, Daniel K; Ryder, Robert W; Weber, David J; Walter, Emmanuel; McKinney, Ross E

2003-11-07

HIV adversely affects growth in children. Pediatric AIDS Clinical Trial Group (PACTG) protocols often use weight velocity [changes in weight z-score for age (WAZ)] as a part of the composite endpoint for phase II and III clinical trials. However, WAZ and height velocity (HAZ) have not been critically compared for their utility as part of the composite endpoint. HAZ and WAZ were compared to predict laboratory and clinical progression of HIV in a retrospective cohort study of HIV-infected children with data from PACTG Protocol 300. In both bivariable and multivariable analyses, changes in HAZ were more closely linked to subsequent progression than WAZ. Children with improved HAZ were somewhat less likely to exhibit virological failure [odds ratio (OR), 0.76; 95% confidence interval (CI) 0.51-1.14], than children with improved WAZ (OR, 1.45; 95% CI, 0.99,2.11). Children who had improved HAZ were less likely to exhibit immunological failure (OR, 0.7; 95% CI, 0.49-1.00), than children with improved WAZ (OR, 1.13; 95% CI, 0.82-1.57). Children who had improved HAZ were less likely to have other forms of clinical progression of HIV (OR, 0.55; 95% CI, 0.31-0.99), than children who had improved WAZ (OR, 1.0; 95% CI, 1.58-1.94). Increases in HAZ were associated with reduced risk of subsequent clinical progression and subsequent immune reconstitution and weakly associated with declines in HIV RNA. Changes in WAZ were not associated with laboratory outcomes relevant to pediatric HIV infection. Height velocity should be considered as a component of a composite clinical endpoint in future PACTG trials.

Construction report of the PF slow-positron source. 1

International Nuclear Information System (INIS)

Enomoto, Atsushi; Kurihara, Toshikazu; Kobayashi, Hitoshi

1993-12-01

The slow positron source utilizing the electron beam of the 2.5 GeV electron beam accelerator which is the synchrotron radiation injector is being constructed. The outline of the project and the present state of construction are reported. As of November, 1993, by injecting the electron beam of about 10 W to the targets for producing positrons, the slow positrons of 4 x 10 4 e + /s has been obtained in the laboratory. Finally, with the electron beam of 30 kW, it is aimed at to obtain the slow positron beam of 2 x 10 9 e + /s. In the slow positron source, the electron beam from the 2.5 GeV linear accelerator is used as the primary beam. This beam is led to the target with electromagnets. Radiation shields were strengthened, and the electrostatic lens system was attached to efficiently extract and send out slow positrons. The conveying system for slow positrons is explained. Primary electron beam, target and moderator for producing slow positrons, the change to continuous current of pulsed slow positron beam and the heightening of luminance of slow positron beam, and the experiment on the utilization of slow positron beam, and the control system for positron conveyance path are reported. (K.I.)

Seismic Velocity Structure and Depth-Dependence of Anisotropy in the Red Sea and Arabian Shield from Surface Wave Analysis

Energy Technology Data Exchange (ETDEWEB)

Hansen, S; Gaherty, J; Schwartz, S; Rodgers, A; Al-Amri, A

2007-07-25

We investigate the lithospheric and upper mantle structure as well as the depth-dependence of anisotropy along the Red Sea and beneath the Arabian Peninsula using receiver function constraints and phase velocities of surface waves traversing two transects of stations from the Saudi Arabian National Digital Seismic Network. Frequency-dependent phase delays of fundamental-mode Love and Rayleigh waves, measured using a cross-correlation procedure, require very slow shear velocities and the presence of anisotropy throughout the upper mantle. Linearized inversion of these data produce path-averaged 1D radially anisotropic models with about 4% anisotropy in the lithosphere, increasing to about 4.8% anisotropy across the lithosphere-asthenosphere boundary (LAB). Models with reasonable crustal velocities in which the mantle lithosphere is isotropic cannot satisfy the data. The lithospheric lid, which ranges in thickness from about 70 km near the Red Sea coast to about 90 km beneath the Arabian Shield, is underlain by a pronounced low-velocity zone with shear velocities as low as 4.1 km/s. Forward models, which are constructed from previously determined shear-wave splitting estimates, can reconcile surface and body wave observations of anisotropy. The low shear velocity values are similar to many other continental rift and oceanic ridge environments. These low velocities combined with the sharp velocity contrast across the LAB may indicate the presence of partial melt beneath Arabia. The anisotropic signature primarily reflects a combination of plate- and density-driven flow associated with active rifting processes in the Red Sea.

Magnon Inflation: Slow Roll with Steep Potentials

CERN Document Server

Adshead, Peter; Burgess, C P; Hayman, Peter; Patil, Subodh P

2016-01-01

We find multi-scalar effective field theories (EFTs) that can achieve a slow inflationary roll despite having a scalar potential that does not satisfy the usual slow-roll condition (d V)^2 << V^2/Mp^2. They evade the usual slow-roll conditions on $V$ because their kinetic energies are dominated by single-derivative terms rather than the usual two-derivative terms. Single derivatives dominate during slow roll and so do not require a breakdown of the usual derivative expansion that underpins calculational control in much of cosmology. The presence of such terms requires some sort of UV Lorentz-symmetry breaking during inflation (besides the usual cosmological breaking). Chromo-natural inflation provides an example of a UV theory that can generate the multi-field single-derivative terms we consider, and we argue that the EFT we find indeed captures the slow-roll conditions for the background evolution for Chromo-natural inflation. We also show that our EFT can be understood as a multi-field generalization ...

[Status of traditional Chinese medicine materials seed and seedling breeding bases].

Science.gov (United States)

Li, Ying; Huang, Lu-Qi; Zhang, Xiao-Bo; Wang, Hui; Cheng, Meng; Zhang, Tian; Yang, Guang

2017-11-01

Seeds and seedlings are the material basis of traditional Chinese medicine materials production, and the construction of traditional Chinese medicine materials seed and seedling breeding bases is beneficial to the production of high-quality traditional Chinese medicine materials. The construction of traditional Chinese medicine materials seed and seedling breeding bases is one of the major topics of Chinese medica resources census pilot. Targets, tasks of traditional Chinese medicine materials seed and seedling breeding bases based on Chinese medica resources census pilot were expounded.Construction progress including hardware construction, germplasm conservation and breeding, procedures and standardsestablishment, social servicesare presented. Development counter measures were proposed for the next step: perfect the standard and system, maintain and strengthen the breeding function, strengthen the cultivation of multi-level talents, explore market development model, joint efforts to deepen services and development. Copyright© by the Chinese Pharmaceutical Association.

Sustainable Development of Slow Fashion Businesses: Customer Value Approach

Directory of Open Access Journals (Sweden)

Sojin Jung

2016-06-01

Full Text Available As an alternative to the prevalent fast fashion model, slow fashion has emerged as a way of enhancing sustainability in the fashion industry, yet how slow fashion can enhance profitability is still largely unknown. Based on a customer value creation framework, this study empirically tested a structural model that specified the slow fashion attributes that contribute to creating perceived customer value, which subsequently increases a consumer’s intention to buy and pay a price premium for slow fashion products. An analysis of 221 U.S. consumer data revealed that delivering exclusive product value is significantly critical in creating customer value for slow fashion, and customer value, in turn, positively affects consumers’ purchase intentions. Further analysis also revealed that different slow fashion attributes distinctively affect customer value. This provides potential strategies on which slow fashion businesses can focus to secure an economically sustainable business model, thereby continuously improving environmental and social sustainability with the slow fashion ideal.

Protecting traditional knowledge of Chinese medicine: concepts and proposals.

Science.gov (United States)

Liu, Changhua; Gu, Man

2011-06-01

With the development of the knowledge economy, knowledge has become one of the most important resources for social progress and economic development. Some countries have proposed measures for the protection of their own traditional knowledge. Traditional Chinese medicine belongs to the category of intangible cultural heritage because it is an important part of Chinese cultural heritage. Today the value of traditional knowledge of Chinese medicine has been widely recognized by the domestic and international public. This paper discusses the definition of traditional knowledge of Chinese medicine and its protection, and evaluates research on its classification. We review the present status of the protection of traditional knowledge of Chinese medicine and tentatively put forward some possible ideas and methods for the protection of traditional knowledge of Chinese medicine. Our goal is to find a way to strengthen the vitality of traditional Chinese medicine and consolidate its foundation. We believe that if we could establish a suitable sui generis(sui generis is a Latin term meaning "of its own kind" and is often used in discussions about protecting the rights of indigenous peoples. Here we use it to emphasize the fact that protection of traditional knowledge of Chinese medicine cannot be achieved through existing legal means of protection alone due to its unique characteristics) system for traditional knowledge, a more favorable environment for the preservation and development of traditional Chinese medicine will ultimately be created.

Slowed ageing, welfare, and population problems.

Science.gov (United States)

Wareham, Christopher

2015-10-01

Biological studies have demonstrated that it is possible to slow the ageing process and extend lifespan in a wide variety of organisms, perhaps including humans. Making use of the findings of these studies, this article examines two problems concerning the effect of life extension on population size and welfare. The first--the problem of overpopulation--is that as a result of life extension too many people will co-exist at the same time, resulting in decreases in average welfare. The second--the problem of underpopulation--is that life extension will result in too few people existing across time, resulting in decreases in total welfare. I argue that overpopulation is highly unlikely to result from technologies that slow ageing. Moreover, I claim that the problem of underpopulation relies on claims about life extension that are false in the case of life extension by slowed ageing. The upshot of these arguments is that the population problems discussed provide scant reason to oppose life extension by slowed ageing.

The slow ionized wind and rotating disklike system that are associated with the high-mass young stellar object G345.4938+01.4677

Energy Technology Data Exchange (ETDEWEB)

Guzmán, Andrés E.; Garay, Guido; Bronfman, Leonardo; Mardones, Diego [Departamento de Astronomía, Universidad de Chile, Camino el Observatorio 1515, Las Condes, Santiago (Chile); Rodríguez, Luis F. [Centro de Radioastronomía y Astrofísica (UNAM), Morelia 58089 (Mexico); Moran, James [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA (United States); Brooks, Kate J. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, 1710 NSW (Australia); Nyman, Lars-Åke [Joint ALMA Observatory (JAO), Alonso de Córdova 3107, Vitacura, Santiago (Chile); Sanhueza, Patricio [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States)

2014-12-01

We report the detection, made using ALMA, of the 92 GHz continuum and hydrogen recombination lines (HRLs) H40α, H42α, and H50β emission toward the ionized wind associated with the high-mass young stellar object G345.4938+01.4677. This is the luminous central dominating source located in the massive and dense molecular clump associated with IRAS 16562–3959. The HRLs exhibit Voigt profiles, which is a strong signature of Stark broadening. We successfully reproduce the observed continuum and HRLs simultaneously using a simple model of a slow ionized wind in local thermodynamic equilibrium, with no need for a high-velocity component. The Lorentzian line wings imply electron densities of 5 × 10{sup 7} cm{sup –3} on average. In addition, we detect SO and SO{sub 2} emission arising from a compact (∼3000 AU) molecular core associated with the central young star. The molecular core exhibits a velocity gradient that is perpendicular to the jet-axis, which we interpret as evidence of rotation. The set of observations toward G345.4938+01.4677 are consistent with it being a young high-mass star associated with a slow photo-ionized wind.

Velocity Models of the Upper Mantle Beneath the MER, Somali Platform, and Ethiopian Highlands from Body Wave Tomography

Science.gov (United States)

Hariharan, A.; Keranen, K. M.; Alemayehu, S.; Ayele, A.; Bastow, I. D.; Eilon, Z.

2016-12-01

The Main Ethiopian Rift (MER) presents a unique opportunity to improve our understanding of an active continental rift. Here we use body wave tomography to generate compressional and shear wave velocity models of the region beneath the rift. The models help us understand the rifting process over the broader region around the MER, extending the geographic region beyond that captured in past studies. We use differential arrival times of body waves from teleseismic earthquakes and multi-channel cross correlation to generate travel time residuals relative to the global IASP91 1-d velocity model. The events used for the tomographic velocity model include 200 teleseismic earthquakes with moment magnitudes greater than 5.5 from our recent 2014-2016 deployment in combination with 200 earthquakes from the earlier EBSE and EAGLE deployments (Bastow et al. 2008). We use the finite-frequency tomography analysis of Schmandt et al. (2010), which uses a first Fresnel zone paraxial approximation to the Born theoretical kernel with spatial smoothing and model norm damping in an iterative LSQR algorithm. Results show a broad, slow region beneath the rift with a distinct low-velocity anomaly beneath the northwest shoulder. This robust and well-resolved low-velocity anomaly is visible at a range of depths beneath the Ethiopian plateau, within the footprint of Oligocene flood basalts, and near surface expressions of diking. We interpret this anomaly as a possible plume conduit, or a low-velocity finger rising from a deeper, larger plume. Within the rift, results are consistent with previous work, exhibiting rift segmentation and low-velocities beneath the rift valley.

Kinetic slow mode-type solitons

Directory of Open Access Journals (Sweden)

K. Baumgärtel

2005-01-01

Full Text Available One-dimensional hybrid code simulations are presented, carried out in order both to study solitary waves of the slow mode branch in an isotropic, collisionless, medium-β plasma (βi=0.25 and to test the fluid based soliton interpretation of Cluster observed strong magnetic depressions (Stasiewicz et al., 2003; Stasiewicz, 2004 against kinetic theory. In the simulations, a variety of strongly oblique, large amplitude, solitons are seen, including solitons with Alfvenic polarization, similar to those predicted by the Hall-MHD theory, and robust, almost non-propagating, solitary structures of slow magnetosonic type with strong magnetic field depressions and perpendicular ion heating, which have no counterpart in fluid theory. The results support the soliton-based interpretation of the Cluster observations, but reveal substantial deficiencies of Hall-MHD theory in describing slow mode-type solitons in a plasma of moderate beta.

Identifying factors contributing to slow growth in pigs.

Science.gov (United States)

He, Y; Deen, J; Shurson, G C; Wang, L; Chen, C; Keisler, D H; Li, Y Z

2016-05-01

Pigs that grow slower than their contemporaries can cause complications for animal welfare and profitability. This study was conducted to investigate factors that may contribute to slow growth of pigs. Pigs ( = 440) farrowed by 65 sows were monitored from birth to market. Pigs were categorized as slow, average, and fast growers based on market weight adjusted to 170 d of age (slow growers were 125 kg). Blood samples were collected from 48 focal pigs at 9 and 21 wk of age and analyzed for hormone and free AA concentrations. Data were analyzed using the Mixed and Logistic procedures of SAS. Slow-growing pigs accounted for 10% of pigs marketed, average growers accounted for 49% of pigs marketed, and fast growers accounted for 41% of pigs marketed. Compared with fast growers, slow growers were lighter at birth ( ratio = 2.17, 95% confidence interval = 1.19 to 3.96, = 0.01). Litter size and parity of the pigs' dam were not associated with slow growth. These results suggest that low concentrations of IGF-1, insulin, leptin, and AA may contribute to or be associated with slow growth in pigs.

Complex rehabilitation and the clinical condition of working rheumatoid arthritis patients: does cryotherapy always overtop traditional rehabilitation?

Science.gov (United States)

Księżopolska-Orłowska, Krystyna; Pacholec, Anna; Jędryka-Góral, Anna; Bugajska, Joanna; Sadura-Sieklucka, Teresa; Kowalik, Katarzyna; Pawłowska-Cyprysiak, Karolina; Łastowiecka-Moras, Elżbieta

2016-01-01

Rehabilitation slows the progress of rheumatoid arthritis (RA) and prevents progression of disability. This study aimed to compare the impact of two rehabilitation programmes on pain, disease activity, locomotor function, global health and work ability forecast in RA patients. Sixty-four employed women aged 24-65 years participated in the study. All patients underwent individual and instrumental kinesiotherapy. Thirty-two patients underwent cryogenic chamber therapy and local cryotherapy as well as non-weight-bearing, instrumental and individual kinesiotherapy. The remaining 32 patients received traditional rehabilitation in the form of electromagnetic and instrumental therapy, individual and pool-based non-weight-bearing kinesiotherapy. Rehabilitation lasted 3 weeks. Patients were examined three times: prior to rehabilitation, after 3 weeks of therapy and 3 months after completion of rehabilitation. The following study instruments were used: to assess disease activity: DAS-28; functional impairment: HAQ-DI; pain severity: VAS; patients' overall well-being: a scale from 0 to 100 (Global Health Index); and patients' own prognosis of fitness for work: the 6th question from Work Ability Index (WAI). Statistical analysis of data was performed using the STATISTICA 8.0 package. Mixed-design two-way analysis of variance was used for hypothesis testing. All patients improved after rehabilitation. The group of patients those who underwent cryotherapy had improved DAS-28, HAQ-DI, VAS and global health scores immediately following the 3-week rehabilitation programme (p cryotherapy resulted in greater improvement in disease activity DAS-28 [F(2,105) = 5.700; p = 0.007; η(2) = 0.084] and HAQ-DI locomotor function scores [F(2,109) = 6.771; p = 0.003; η(2) = 0.098] compared to traditional rehabilitation. The impact of both forms of rehabilitation on patients' own prognosis of work ability in the next 2 years was not significant. Results of patients who underwent

Slow rupture of frictional interfaces

OpenAIRE

Sinai, Yohai Bar; Brener, Efim A.; Bouchbinder, Eran

2011-01-01

The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not comple...

Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Energy Technology Data Exchange (ETDEWEB)

Durand, O.; Soulard, L. [CEA, DAM, DIF, F-91297 Arpajon (France)

2015-04-28

The mass (volume and areal densities) versus velocity as well as the size versus velocity distributions of a shock-induced cloud of particles are investigated using large scale molecular dynamics simulations. A generic three-dimensional tin crystal with a sinusoidal free surface roughness (single wavelength) is set in contact with vacuum and shock-loaded so that it melts directly on shock. At the reflection of the shock wave onto the perturbations of the free surface, two-dimensional sheets/jets of liquid metal are ejected. The simulations show that the distributions may be described by an analytical model based on the propagation of a fragmentation zone, from the tip of the sheets to the free surface, in which the kinetic energy of the atoms decreases as this zone comes closer to the free surface on late times. As this kinetic energy drives (i) the (self-similar) expansion of the zone once it has broken away from the sheet and (ii) the average size of the particles which result from fragmentation in the zone, the ejected mass and the average size of the particles progressively increase in the cloud as fragmentation occurs closer to the free surface. Though relative to nanometric scales, our model may help in the analysis of experimental profiles.

An analytical model for displacement velocity of liquid film on a hot vertical surface

International Nuclear Information System (INIS)

Yoshioka, Keisuke; Hasegawa, Shu

1975-01-01

The downward progress of the advancing front of a liquid film streaming down a heated vertical surface, as it would occur in emergency core cooling, is much slower than in the case of ordinary streaming down along a heated surface already wetted with the liquid. A two-dimensional heat conduction model is developed for evaluating this velocity of the liquid front, which takes account of the heat removal by ordinary flow boiling mechanism. In the analysis, the maximum heat flux and the calefaction temperature are taken up as parameters in addition to the initial dry heated wall temperature, the flow rate and the velocity of downward progress of the liquid front. The temperature profile is calculated for various combinations of these parameters. Two criteria are proposed for choosing the most suitable combination of the parameters. One is to reject solutions that represent an oscillating wall temperature distribution, and the second criterion requires that the length of the zone of violent boiling immediately following the liquid front should not be longer than about 1 mm, this value being determined from comparisons made between experiment and calculation. Application of the above two criteria resulted in reasonable values obtained for the calefaction temperature and the maximum heat flux, and the velocity of the liquid front derived therefrom showed good agreement with experiment. (auth.)

Referencing geostrophic velocities using ADCP data Referencing geostrophic velocities using ADCP data

Directory of Open Access Journals (Sweden)

Isis Comas-Rodríguez

2010-06-01

Full Text Available Acoustic Doppler Current Profilers (ADCPs have proven to be a useful oceanographic tool in the study of ocean dynamics. Data from D279, a transatlantic hydrographic cruise carried out in spring 2004 along 24.5°N, were processed, and lowered ADCP (LADCP bottom track data were used to assess the choice of reference velocity for geostrophic calculations. The reference velocities from different combinations of ADCP data were compared to one another and a reference velocity was chosen based on the LADCP data. The barotropic tidal component was subtracted to provide a final reference velocity estimated by LADCP data. The results of the velocity fields are also shown. Further studies involving inverse solutions will include the reference velocity calculated here.

Changes in speed skating velocity in relation to push-off effectiveness.

Science.gov (United States)

Noordhof, Dionne A; Foster, Carl; Hoozemans, Marco J M; de Koning, Jos J

2013-03-01

Speed skating posture, or technique, is characterized by the push-off angle or effectiveness (e), determined as the angle between the push-off leg and the ice; the preextension knee angle (θ(0)); and the trunk angle (θ(1)). Together with muscle-power output and environmental conditions, skating posture, or technique, determines velocity (v). To gain insight into technical variables that are important to skate efficiently and perform well, e, θ(0), θ(1), and skating v were determined every lap during a 5000-m World Cup. Second, the authors evaluated if changes (Δ) in e, θ(0), and θ(1) are associated with Δv. One camera filmed the skaters from a frontal view, from which e was determined. Another camera filmed the skaters from a sagittal view, from which θ(0) and θ(1) were determined. Radio-frequency identification tags around the ankles of the skaters measured v. During the race, e progressively increased and v progressively decreased, while θ(0) and θ(1) showed a less consistent pattern of change. Generalized estimating equations showed that Δe is significantly associated with Δv over the midsection of the race (β = -0.10, P < .001) and that Δθ(0) and Δθ(1) are not significantly associated with Δv. The decrease in skating v over the race is not due to increases in power losses to air friction, as knee and trunk angle were not significantly associated with changes in velocity. The decrease in velocity can be partly ascribed to the decrease in effectiveness, which reflects a decrease in power production associated with fatigue.

One- and two-electron processes in collisions between hydrogen molecules and slow highly charged ions

International Nuclear Information System (INIS)

Wells, E.; Carnes, K.D.; Tawara, H.; Ali, R.; Sidky, Emil Y.; Illescas, Clara; Ben-Itzhak, I.

2005-01-01

A coincidence time-of-flight technique coupled with projectile charge state analysis was used to study electron capture in collisions between slow highly charged ions and hydrogen molecules. We found single electron capture with no target excitation to be the dominant process for both C 6+ projectiles at a velocity of 0.8 atomic units and Ar 11+ projectiles at v 0.63 a.u. Double electron capture and transfer excitation, however, were found to be comparable and occur about 30% of the time relative to single capture. Most projectiles (96%) auto-ionize quickly following double capture into doubly excited states. The data are compared to classical and quantum mechanical model calculations

Free-surface velocity measurements using an optically recording velocity interferometer

International Nuclear Information System (INIS)

Lu Jianxin; Wang Zhao; Liang Jing; Shan Yusheng; Zhou Chuangzhi; Xiang Yihuai; Lu Ze; Tang Xiuzhang

2006-01-01

An optically recording velocity interferometer system (ORVIS) was developed for the free-surface velocity measurements in the equation of state experiments. The time history of free-surface velocity could be recorded by the electronic streak camera. In the experiments, ORVIS got a 179 ps time resolution, and a higher time resolution could be got by minimizing the delay time. The equation of state experiments were carried out on the high power excimer laser system called 'Heaven I' with laser wavelength of 248.4 nm, pulse duration of 25 ns and maximum energy 158 J. Free-surface velocity of 20 μm thick iron got 3.86 km/s with laser intensity of 6.24 x 10 11 W·cm -2 , and free-surface velocity of 100 μm thick aluminum with 100 μm CH foil at the front got 2.87 km/s with laser intensity 7.28 x 10 11 W·cm -2 . (authors)

Small angle scattering of X radiation and slow neutrons in structural analyses of amorphous solids

International Nuclear Information System (INIS)

Kostorz, G.

1980-01-01

Small angle scattering of x radiation and slow neutrons allows to detect inhomogeneities of the dimension of ten to some thousands of Angstroem by the difference in the scattering length density. The progress made during recent years in the development of apparatusses has created the possibility of solving very complicated problems. A first outline shows that in separation processes as well as in investigating extended defects the method of small angle scattering may provide valuable contributions to the analysis of the non-crystalline state

Simultaneous velocity and pressure quantification using pressure-sensitive flow tracers in air

Science.gov (United States)

Zhang, Peng; Peterson, Sean; Porfiri, Maurizio

2017-11-01

Particle-based measurement techniques for assessing the velocity field of a fluid have advanced rapidly over the past two decades. Full-field pressure measurement techniques have remained elusive, however. In this work, we aim to demonstrate the possibility of direct simultaneous planar velocity and pressure measurement of a high speed aerodynamic flow by employing novel pressure-sensitive tracer particles for particle image velocimetry (PIV). Specifically, the velocity and pressure variations of an airflow through a converging-diverging channel are studied. Polystyrene microparticles embedded with a pressure-sensitive phosphorescent dye-platinum octaethylporphyrin (PtOEP)-are used as seeding particles. Due to the oxygen quenching effect, the emission lifetime of PtOEP is highly sensitive to the oxygen concentration, that is, the partial pressure of oxygen, in the air. Since the partial pressure of oxygen is linearly proportional to the air pressure, we can determine the air pressure through the phosphorescence emission lifetime of the dye. The velocity field is instead obtained using traditional PIV methods. The particles have a pressure resolution on the order of 1 kPa, which may be improved by optimizing the particle size and dye concentration to suit specific flow scenarios. This work was supported by the National Science Foundation under Grant Number CBET-1332204.

On linear relationship between shock velocity and particle velocity

International Nuclear Information System (INIS)

Dandache, H.

1986-11-01

We attempt to derive the linear relationship between shock velocity U s and particle velocity U p from thermodynamic considerations, taking into account an ideal gas equation of state and a Mie-Grueneisen equation of state for solids. 23 refs

Shear-wave velocities beneath the Harrat Rahat volcanic field, Saudi Arabia, using ambient seismic noise analysis

Science.gov (United States)

Civilini, F.; Mooney, W.; Savage, M. K.; Townend, J.; Zahran, H. M.

2017-12-01

We present seismic shear-velocities for Harrat Rahat, a Cenozoic bimodal alkaline volcanic field in west-central Saudi Arabia, using seismic tomography from natural ambient noise. This project is part of an overall effort by the Saudi Geological Survey and the United States Geological Survey to describe the subsurface structure and assess hazards within the Saudi Arabian shield. Volcanism at Harrat Rahat began approximately 10 Ma, with at least three pulses around 10, 5, and 2 Ma, and at least several pulses in the Quaternary from 1.9 Ma to the present. This area is instrumented by 14 broadband Nanometrics Trillium T120 instruments across an array aperture of approximately 130 kilometers. We used a year of recorded natural ambient noise to determine group and phase velocity surface wave dispersion maps with a 0.1 decimal degree resolution for radial-radial, transverse-transverse, and vertical-vertical components of the empirical Green's function. A grid-search method was used to carry out 1D shear-velocity inversions at each latitude-longitude point and the results were interpolated to produce pseudo-3D shear velocity models. The dispersion maps resolved a zone of slow surface wave velocity south-east of the city of Medina spatially correlated with the 1256 CE eruption. A crustal layer interface at approximately 20 km depth was determined by the inversions for all components, matching the results of prior seismic-refraction studies. Cross-sections of the 3D shear velocity models were compared to gravity measurements obtained in the south-east edge of the field. We found that measurements of low gravity qualitatively correlate with low values of shear-velocity below 20 km along the cross-section profile. We apply these methods to obtain preliminary tomography results on the entire Arabian Shield.

Traditional Chinese medicines and Alzheimer’s disease

Directory of Open Access Journals (Sweden)

Tzong-Yuan Wu

2011-06-01

Full Text Available Traditional Chinese medicines have been widely investigated for the treatment of Alzheimer’s disease (AD because none of the current therapies—either the cholinesterase inhibitors or antagonist of N-methyl-d-aspartate receptors—has profound effects on halting the progression of AD. In recent years, scientists have isolated many active compounds from herbs, which can alleviate dementia and neurodegenerative syndrome with fewer side effects than conventional drugs and, thus, are regarded as promising drug candidates for AD therapy. In this review, we summarize the latest research progress on six herbs for AD therapy—Huperzia serrata, Amaryllidaceae family, Ginkgo biloba, Uncaria rhynchophylla, Polygala tenuifolia, and Salvia officinalis—and focus on the analysis of their active components and possible mechanisms of pharmacological actions on AD.

Efficiency enhancement of slow-wave electron-cyclotron maser by a second-order shaping of the magnetic field in the low-gain limit

Energy Technology Data Exchange (ETDEWEB)

Liu, Si-Jia; Zhang, Yu-Fei; Wang, Kang [School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Yong-Ming [Information Science and Engineering College, XinJiang University, Urumqi XinJiang 830046 (China); Jing, Jian, E-mail: jingjian@mail.buct.edu.cn [School of Science, Beijing University of Chemical Technology, Beijing 100029 (China)

2017-03-15

Based on the anomalous Doppler effect, we put forward a proposal to enhance the conversion efficiency of the slow-wave electron cyclotron masers (ECM) under the resonance condition. Compared with previous studies, we add a second-order shaping term in the guild magnetic field. Theoretical analyses and numerical calculations show that it can enhance the conversion efficiency in the low-gain limit. The case of the initial velocity spread of electrons satisfying the Gaussian distribution is also analysed numerically.

Determination of the filtration velocities and mean velocity in ground waters using radiotracers

International Nuclear Information System (INIS)

Duran P, Oscar; Diaz V, Francisco; Heresi M, Nelida

1994-01-01

An experimental method to determine filtration, or, Darcy velocity and mean velocity in underground waters using radiotracers, is described. After selecting the most appropriate tracers, from 6 chemical compounds, to measure water velocity, a method to measure filtration velocity was developed. By fully labelling the water column with 2 radioisotopes, Br and tritium, almost identical values were obtained for the aquifer filtration velocity in the sounding S1. This value was 0.04 m/d. Field porosity was calculated at 11% and mean velocity at 0.37 m.d. With the filtration velocity value and knowing the hydraulic variation between the soundings S1 and S2 placed at 10 meters, field permeability was estimated at 2.4 x 10 m/s. (author)

Slow Earthquakes in the Alaska-Aleutian Subduction Zone Detected by Multiple Mini Seismic Arrays

Science.gov (United States)

LI, B.; Ghosh, A.; Thurber, C. H.; Lanza, F.

2017-12-01

The Alaska-Aleutian subduction zone is one of the most seismically and volcanically active plate boundaries on earth. Compared to other subduction zones, the slow earthquakes, such as tectonic tremors (TTs) and low frequency earthquakes (LFEs), are relatively poorly studied due to the limited data availability and difficult logistics. The analysis of two-months of continuous data from a mini array deployed in 2012 shows abundant tremor and LFE activities under Unalaska Island that is heterogeneously distributed [Li & Ghosh, 2017]. To better study slow earthquakes and understand their physical characteristics in the study region, we deployed a hybrid array of arrays, consisting of three well-designed mini seismic arrays and five stand alone stations, in the Unalaska Island in 2014. They were operational for between one and two years. Using the beam back-projection method [Ghosh et al., 2009, 2012], we detect continuous tremor activities for over a year when all three arrays are running. The sources of tremors are located south of the Unalaska and Akutan Islands, at the eastern and down-dip edge of the rupture zone of the 1957 Mw 8.6 earthquake, and they are clustered in several patches, with a gap between the two major clusters. Tremors show multiple migration patterns with propagation in both along-strike and dip directions and a wide range of velocities. We also identify tens of LFE families and use them as templates to search for repeating LFE events with the matched-filter method. Hundreds to thousands of LFEs for each family are detected and their activities are spatiotemporally consistent with tremor activities. The array techniques are revealing a near-continuous tremor activity in this area with remarkable spatiotemporal details. It helps us to better recognize the physical properties of the transition zone, provides new insights into the slow earthquake activities in this area, and explores their relation with the local earthquakes and the potential slow

Radial velocity asymmetries from jets with variable velocity profiles

International Nuclear Information System (INIS)

Cerqueira, A. H.; Vasconcelos, M. J.; Velazquez, P. F.; Raga, A. C.; De Colle, F.

2006-01-01

We have computed a set of 3-D numerical simulations of radiatively cooling jets including variabilities in both the ejection direction (precession) and the jet velocity (intermittence), using the Yguazu-a code. In order to investigate the effects of jet rotation on the shape of the line profiles, we also introduce an initial toroidal rotation velocity profile. Since the Yguazu-a code includes an atomic/ionic network, we are able to compute the emission coefficients for several emission lines, and we generate line profiles for the Hα, [O I]λ6300, [S II]λ6716 and [N II]λ6548 lines. Using initial parameters that are suitable for the DG Tau microjet, we show that the computed radial velocity shift for the medium-velocity component of the line profile as a function of distance from the jet axis is strikingly similar for rotating and non-rotating jet models

Threshold Characteristics of Slow-Light Photonic Crystal Lasers

DEFF Research Database (Denmark)

Xue, Weiqi; Yu, Yi; Ottaviano, Luisa

2016-01-01

The threshold properties of photonic crystal quantum dot lasers operating in the slow-light regime are investigated experimentally and theoretically. Measurements show that, in contrast to conventional lasers, the threshold gain attains a minimum value for a specific cavity length. The experimental...... results are explained by an analytical theory for the laser threshold that takes into account the effects of slow light and random disorder due to unavoidable fabrication imperfections. Longer lasers are found to operate deeper into the slow-light region, leading to a trade-off between slow-light induced...

Upper mantle low velocity heterogeneities beneath NE China revealed by source- and receiver-side converted waves

Science.gov (United States)

Guan, Z.; Niu, F.

2017-12-01

Common-conversion-point (CCP) stacking of receiver function is a powerful tool in mapping upper mantle heterogeneities. However, reverberations from shallow boundaries with large velocity contrast could contaminate the imaging profiles severely. Applying the refined Slowness Weighted CCP (SWCCP) stacking technique (Guan and Niu, 2017) on NECESSArray data, we eliminated the multiple effects and systematically imaged the upper mantle low velocity heterogeneities in NE China where there exist rich unconsolidated sediments. The SWCCP profiles reveal a 350 km low velocity heterogeneity which is possibly associated with the Changbai Mountain volcanism and interpreted as a negatively buoyant silicate melt lying atop of the 410 km discontinuity. Besides, the imaging results are also suggestive of a sporadic 580-620 km low velocity heterogeneity locating in the easternmost part of NE China with a velocity contrast comparable with the 660-km discontinuity. In addition, between 42º N and 45º N, we also found a double 660-km discontinuity at the two sides of the localized depression in the longitudinal range of 128º E to 131º E. On the other hand, we gathered USArray and Alaska regional array seismic data of deep earthquakes occurring beneath NE China and the surrounding areas and employed stacking technique to study the source side S-to-P conversions. The source-side stacking also showed a strong S-to-P conversion at 600 km deep, consistent with the SWCCP stacks. Meanwhile, we also confirmed the double 660-km discontinuity feature from the source-side conversions. The receiver- and source-side observations provide strong constraints on these low velocity anomalies that may offer insights on the subduction dynamics of the Pacific plate.

Slow brushing reduces heat pain in humans.

Science.gov (United States)

Liljencrantz, J; Strigo, I; Ellingsen, D M; Krämer, H H; Lundblad, L C; Nagi, S S; Leknes, S; Olausson, H

2017-08-01

C-tactile (CT) afferents are unmyelinated low-threshold mechanoreceptors optimized for signalling affective, gentle touch. In three separate psychophysical experiments, we examined the contribution of CT afferents to pain modulation. In total, 44 healthy volunteers experienced heat pain and CT optimal (slow brushing) and CT sub-optimal (fast brushing or vibration) stimuli. Three different experimental paradigms were used: Concurrent application of heat pain and tactile (slow brushing or vibration) stimulation; Slow brushing, applied for variable duration and intervals, preceding heat pain; Slow versus fast brushing preceding heat pain. Slow brushing was effective in reducing pain, whereas fast brushing or vibration was not. The reduction in pain was significant not only when the CT optimal touch was applied simultaneously with the painful stimulus but also when the two stimuli were separated in time. For subsequent stimulation, the pain reduction was more pronounced for a shorter time interval between brushing and pain. Likewise, the effect was more robust when pain was preceded by a longer duration of brush stimulation. Strong CT-related pain reduction was associated with low anxiety and high calmness scores obtained by a state anxiety questionnaire. Slow brushing - optimal for CT activation - is effective in reducing pain from cutaneous heating. The precise mechanisms for the pain relief are as yet unknown but possible mechanisms include inhibition of nociceptive projection neurons at the level of the dorsal horn as well as analgesia through cortical mechanisms. Slow brushing stimuli - optimal for activation of C-tactile fibres - can reduce pain from cutaneous heating. No such effect was seen with fast brushing or vibration. These observations indicate the role of C-tactile fibres in pain modulation. © 2017 European Pain Federation - EFIC®.

Tandem queue with server slow-down

NARCIS (Netherlands)

Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

2007-01-01

We study how rare events happen in the standard two-node tandem Jackson queue and in a generalization, the socalled slow-down network, see [2]. In the latter model the service rate of the first server depends on the number of jobs in the second queue: the first server slows down if the amount of

Velocity Drives Greater Power Observed During Back Squat Using Cluster Sets.

Science.gov (United States)

Oliver, Jonathan M; Kreutzer, Andreas; Jenke, Shane C; Phillips, Melody D; Mitchell, Joel B; Jones, Margaret T

2016-01-01

This investigation compared the kinetics and kinematics of cluster sets (CLU) and traditional sets (TRD) during back squat in trained (RT) and untrained (UT) men. Twenty-four participants (RT = 12, 25 ± 1 year, 179.1 ± 2.2 cm, 84.6 ± 2.1 kg; UT = 12, 25 ± 1 year, 180.1 ± 1.8 cm, 85.4 ± 3.8 kg) performed TRD (4 × 10, 120-second rest) and CLU (4 × (2 × 5) 30 seconds between clusters; 90 seconds between sets) with 70% one repetition maximum, randomly. Kinematics and kinetics were sampled through force plate and linear position transducers. Resistance-trained produced greater overall force, velocity, and power; however, similar patterns were observed in all variables when comparing conditions. Cluster sets produced significantly greater force in isolated repetitions in sets 1-3, while consistently producing greater force due to a required reduction in load during set 4 resulting in greater total volume load (CLU, 3302.4 ± 102.7 kg; TRD, 3274.8 ± 102.8 kg). Velocity loss was lessened in CLU resulting in significantly higher velocities in sets 2 through 4. Furthermore, higher velocities were produced by CLU during later repetitions of each set. Cluster sets produced greater power output for an increasing number of repetitions in each set (set 1, 5 repetitions; sets 2 and 3, 6 repetitions; set 4, 8 repetitions), and the difference between conditions increased over subsequent sets. Time under tension increased over each set and was greater in TRD. This study demonstrates greater power output is driven by greater velocity when back squatting during CLU; therefore, velocity may be a useful measure by which to assess power.

Slow-transit Constipation.

Science.gov (United States)

Bharucha, Adil E.; Philips, Sidney F.

2001-08-01

Idiopathic slow-transit constipation is a clinical syndrome predominantly affecting women, characterized by intractable constipation and delayed colonic transit. This syndrome is attributed to disordered colonic motor function. The disorder spans a spectrum of variable severity, ranging from patients who have relatively mild delays in transit but are otherwise indistinguishable from irritable bowel syndrome to patients with colonic inertia or chronic megacolon. The diagnosis is made after excluding colonic obstruction, metabolic disorders (hypothyroidism, hypercalcemia), drug-induced constipation, and pelvic floor dysfunction (as discussed by Wald ). Most patients are treated with one or more pharmacologic agents, including dietary fiber supplementation, saline laxatives (milk of magnesia), osmotic agents (lactulose, sorbitol, and polyethylene glycol 3350), and stimulant laxatives (bisacodyl and glycerol). A subtotal colectomy is effective and occasionally is indicated for patients with medically refractory, severe slow-transit constipation, provided pelvic floor dysfunction has been excluded or treated.

Velocity potential formulations of highly accurate Boussinesq-type models

DEFF Research Database (Denmark)

Bingham, Harry B.; Madsen, Per A.; Fuhrman, David R.

2009-01-01

, B., 2006. A Boussinesq-type method for fully nonlinear waves interacting with a rapidly varying bathymetry. Coast. Eng. 53, 487-504); Jamois et al. (Jamois, E., Fuhrman, D.R., Bingham, H.B., Molin, B., 2006. Wave-structure interactions and nonlinear wave processes on the weather side of reflective...... with the kinematic bottom boundary condition. The true behaviour of the velocity potential formulation with respect to linear shoaling is given for the first time, correcting errors made by Jamois et al. (Jamois, E., Fuhrman, D.R., Bingham, H.B., Molin, B., 2006. Wave-structure interactions and nonlinear wave...... processes on the weather side of reflective structures. Coast. Eng. 53, 929-945). An exact infinite series solution for the potential is obtained via a Taylor expansion about an arbitrary vertical position z=(z) over cap. For practical implementation however, the solution is expanded based on a slow...

Propagation of the Semidiurnal Internal Tide: Phase Velocity Versus Group Velocity

Science.gov (United States)

Zhao, Zhongxiang

2017-12-01

The superposition of two waves of slightly different wavelengths has long been used to illustrate the distinction between phase velocity and group velocity. The first-mode M2 and S2 internal tides exemplify such a two-wave model in the natural ocean. The M2 and S2 tidal frequencies are 1.932 and 2 cycles per day, respectively, and their superposition forms a spring-neap cycle in the semidiurnal band. The spring-neap cycle acts like a wave, with its frequency, wave number, and phase being the differences of the M2 and S2 internal tides. The spring-neap cycle and energy of the semidiurnal internal tide propagate at the group velocity. Long-range propagation of M2 and S2 internal tides in the North Pacific is observed by satellite altimetry. Along a 3,400 km beam spanning 24°-54°N, the M2 and S2 travel times are 10.9 and 11.2 days, respectively. For comparison, it takes the spring-neap cycle 21.1 days to travel over this distance. Spatial maps of the M2 phase velocity, the S2 phase velocity, and the group velocity are determined from phase gradients of the corresponding satellite observed internal tide fields. The observed phase and group velocities agree with theoretical values estimated using the World Ocean Atlas 2013 annual-mean ocean stratification.

Labor progress indices and dynamics of the individual uterine contraction during the active stage of labor.

Science.gov (United States)

Ophir, Ella; Bornstein, Jacob; Odeh, Marwan; Kaminsky, Svetlana; Shnaider, Oleg; Megel, Yuri; Barnea, Ofer

2014-03-01

To obtain and study new data on the dynamics of the labor process and to develop a contraction-based index of labor progress. This study was carried out at the Delivery Room, Department of Obstetrics and Gynecology, Western Galilee Hospital, Nahariya, Israel, using a new device (Birth Track). We continuously monitored cervical dilatation (CD) and head descent (HD) in 30 nulliparaous women during active labor with (augmented group) and without (study group) oxytocin augmentation. This led to the development and validation of progress indices based on features extracted from continuous monitoring. There were no significant differences between the average of each parameter in the study and augmented groups, except for HD velocity. Average HD velocity was faster in the study group. Linear regression analyses demonstrated that head station (HS) amplitude and Toco amplitude were the best parameters for predicting HD velocity in both groups. In the study group, average HD velocity was also significantly related to Toco rate and contraction efficiency. In the augmented group, only a weak correlation with Toco rate was seen, and no correlation with contraction efficiency. With the assistance of the Birth Track device, we can obtain continuous data on the labor process and indices to estimate the labor progress process without the use of vaginal (manual) examination. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

Research progress of traditional Chinese medicine extract for retinal ischemia-reperfusion injury

Directory of Open Access Journals (Sweden)

Qian-Yu Jia

2015-05-01

Full Text Available Retinal ischemia-reperfusion injury(RIRIis a common clinical disease, and the producing mechanism is still in research. Experimental and clinical research in recent years have showed that the mechanism of RIRI and oxygen free radicals, gene regulation, calcium overload, inflammatory cytokines and other factors are closely related. In this article, we summarized the current situation that the scholars at home and abroad study traditional Chinese medicine extract of prevention and treatment of RIRI.

Slowing and cooling of heavy or light (even with a tiny electric dipole moment) polar molecules using a novel, versatile electrostatic Stark decelerator.

Science.gov (United States)

Wang, Qin; Hou, Shunyong; Xu, Liang; Yin, Jianping

2016-02-21

To meet some demands for realizing precise measurements of an electric dipole moment of electron (eEDM) and examining cold collisions or cold chemical physics, we have proposed a novel, versatile electrostatic Stark decelerator with an array of true 3D electric potential wells, which are created by a series of horizontally-oriented, U-shaped electrodes with time-sequence controlling high voltages (± HV) and two guiding electrodes with a constant voltage. We have calculated the 2D electric field distribution, the Stark shifts of the four lowest rotational sub-levels of PbF molecules in the X1(2)Π1/2(v = 0) electronic and vibrational ground states as well as the population in the different rotational levels. We have discussed the 2D longitudinal and transverse phase-space acceptances of PbF molecules in our decelerator. Subsequently, we have simulated the dynamic processes of the decelerated PbF molecules using the 3D Monte-Carlo method, and have found that a supersonic PbF beam with a velocity of 300 m s(-1) can be efficiently slowed to about 5 m s(-1), which will greatly enhance the sensitivities to research a parity violation and measure an eEDM. In addition, we have investigated the dependences of the longitudinal velocity spread, longitudinal temperature and bunching efficiency on both the number of guiding stages and high voltages, and found that after bunching, a cold packet of PbF molecules in the J = 7/2, MΩ = -7/4 state with a longitudinal velocity spread of 0.69 m s(-1) (corresponding to a longitudinal temperature of 2.35 mK) will be produced by our high-efficient decelerator, which will generate a high energy-resolution molecular beam for studying cold collision physics. Finally, our novel decelerator can also be used to efficiently slow NO molecules with a tiny electric dipole moment (EDM) of 0.16 D from 315 m s(-1) to 28 m s(-1). It is clear that our proposed new decelerator has a good slowing performance and experimental feasibility as well as wide

A simple measuring technique of surface flow velocity to analyze the behavior of velocity fields in hydraulic engineering applications.

Science.gov (United States)

Tellez, Jackson; Gomez, Manuel; Russo, Beniamino; Redondo, Jose M.

2015-04-01

An important achievement in hydraulic engineering is the proposal and development of new techniques for the measurement of field velocities in hydraulic problems. The technological advances in digital cameras with high resolution and high speed found in the market, and the advances in digital image processing techniques now provides a tremendous potential to measure and study the behavior of the water surface flows. This technique was applied at the Laboratory of Hydraulics at the Technical University of Catalonia - Barcelona Tech to study the 2D velocity fields in the vicinity of a grate inlet. We used a platform to test grate inlets capacity with dimensions of 5.5 m long and 4 m wide allowing a zone of useful study of 5.5m x 3m, where the width is similar of the urban road lane. The platform allows you to modify the longitudinal slopes from 0% to 10% and transversal slope from 0% to 4%. Flow rates can arrive to 200 l/s. In addition a high resolution camera with 1280 x 1024 pixels resolution with maximum speed of 488 frames per second was used. A novel technique using particle image velocimetry to measure surface flow velocities has been developed and validated with the experimental data from the grate inlets capacity. In this case, the proposed methodology can become a useful tools to understand the velocity fields of the flow approaching the inlet where the traditional measuring equipment have serious problems and limitations. References DigiFlow User Guide. (2012), (June). Russo, B., Gómez, M., & Tellez, J. (2013). Methodology to Estimate the Hydraulic Efficiency of Nontested Continuous Transverse Grates. Journal of Irrigation and Drainage Engineering, 139(10), 864-871. doi:10.1061/(ASCE)IR.1943-4774.0000625 Teresa Vila (1), Jackson Tellez (1), Jesus Maria Sanchez (2), Laura Sotillos (1), Margarita Diez (3, 1), and J., & (1), M. R. (2014). Diffusion in fractal wakes and convective thermoelectric flows. Geophysical Research Abstracts - EGU General Assembly 2014

Hybrid metal-dielectric, slow wave structure with magnetic coupling and compensation

Energy Technology Data Exchange (ETDEWEB)

Smirnov, A.V., E-mail: asmirnov@radiabeam.com [RadiaBeam Systems LLC, 1713 Stewart St., Santa Monica, CA 90404 (United States); Savin, E. [RadiaBeam Systems LLC, 1713 Stewart St., Santa Monica, CA 90404 (United States); National Research Nuclear University “MEPhI”, Moscow 115409 (Russian Federation)

2016-06-01

A number of electron beam vacuum devices such as small radiofrequency (RF) linear accelerators (linacs) and microwave traveling wave tubes (TWTs) utilize slow wave structures which are usually rather complicated in production and may require multi-step brazing and time consuming tuning. Fabrication of these devices becomes challenging at centimeter wavelengths, at large number of cells, and when a series or mass production of such structures is required. A hybrid, metal-dielectric, periodic structure for low gradient, low beam current applications is introduced here as a modification of Andreev’s disk-and-washer (DaW) structure. Compensated type of coupling between even and odd TE01 modes in the novel structure results in negative group velocity with absolute values as high as 0.1c–0.2c demonstrated in simulations. Sensitivity to material imperfections and electrodynamic parameters of the disk-and-ring (DaR) structure are considered numerically using a single cell model.

Determination of velocity correction factors for real-time air velocity monitoring in underground mines.

Science.gov (United States)

Zhou, Lihong; Yuan, Liming; Thomas, Rick; Iannacchione, Anthony

2017-12-01

When there are installations of air velocity sensors in the mining industry for real-time airflow monitoring, a problem exists with how the monitored air velocity at a fixed location corresponds to the average air velocity, which is used to determine the volume flow rate of air in an entry with the cross-sectional area. Correction factors have been practically employed to convert a measured centerline air velocity to the average air velocity. However, studies on the recommended correction factors of the sensor-measured air velocity to the average air velocity at cross sections are still lacking. A comprehensive airflow measurement was made at the Safety Research Coal Mine, Bruceton, PA, using three measuring methods including single-point reading, moving traverse, and fixed-point traverse. The air velocity distribution at each measuring station was analyzed using an air velocity contour map generated with Surfer ® . The correction factors at each measuring station for both the centerline and the sensor location were calculated and are discussed.

Pedestrian Dharma: Slowness and Seeing in Tsai Ming-Liang’s Walker

Directory of Open Access Journals (Sweden)

Teng-Kuan Ng

2018-06-01

Full Text Available This paper studies the ways that Walker, a short film by the Malaysian-Taiwanese auteur Tsai Ming-Liang, visualizes the relationship between Buddhism and modernity. Via detailed film analysis as well as attention to sources in premodern Buddhist traditions, this paper argues that its filmic performance of Zen walking meditation serves two functions: To present slowness and simplicity as prophetic counterpoints against the dizzying excesses of the contemporary metropolis; and to offer contemplative attentiveness as a therapeutic resource for life in the modern world. By instantiating and cultivating critical shifts in viewerly perspective in the manner of Buddhist ritual practice, Walker invites us to envision how a place of frenetic distraction or pedestrian mundaneness might be transfigured into a site of beauty, wonder, and liberation.

Kinetic Alfven waves and electron physics. II. Oblique slow shocks

International Nuclear Information System (INIS)

Yin, L.; Winske, D.; Daughton, W.

2007-01-01