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Sample records for unipedal stance time

  1. Frontal plane hip and ankle sensorimotor function, not age, predicts unipedal stance time

    PubMed Central

    Allet, Lara; Kim, Hogene; Ashton-Miller, James; De Mott, Trina; Richardson, James K.

    2011-01-01

    Introduction Changes occur in muscles and nerves with aging. This study aimed to explore the relationship between unipedal stance time (UST) and frontal plane hip and ankle sensorimotor function in subjects with diabetic neuropathy. Methods UST, quantitative measures of frontal plane ankle proprioceptive thresholds, and ankle and hip motor function were tested in forty-one persons with a spectrum of lower limb sensorimotor function, ranging from healthy to moderately severe diabetic neuropathy. Results Frontal plane hip and ankle sensorimotor function demonstrated significant relationships with UST. Multivariate analysis identified only composite hip strength, composite ankle proprioceptive threshold, and age to be significant predictors of UST (R2=0.73); they explained 46%, 24% and 3% of the variance, respectively. Discussion/Conclusions Frontal plane hip strength was the single best predictor of UST and appeared to compensate for less precise ankle proprioceptive thresholds. This finding is clinically relevant given the possibility of strengthening the hip, even in patients with significant PN. . PMID:22431092

  2. Effects of external pelvic compression on electromyographic activity of the hamstring muscles during unipedal stance in sportsmen with and without hamstring injuries.

    PubMed

    Arumugam, Ashokan; Milosavljevic, Stephan; Woodley, Stephanie; Sole, Gisela

    2015-06-01

    There is some evidence that hamstring function can be influenced by interventions focusing on the pelvis via an anatomic and neurophysiologic link between these two segments. Previous research demonstrated increased electromyographic activity from injured hamstrings during transition from bipedal to unipedal stance (BUS). The aim of this study was to investigate the effects of a pelvic compression belt (PCB) on electromyographic activity of selected muscles during BUS in sportsmen with and without hamstring injury. Electromyographic amplitudes (normalised to maximum voluntary isometric contraction [MVIC]) of the hamstrings, gluteus maximus, gluteus medius and lumbar multifidus were obtained during BUS from 20 hamstring-injured participants (both sides) and 30 healthy participants (one side, randomly selected). There was an increase in biceps femoris (by 1.23 ± 2.87 %MVIC; p = 0.027) and gluteus maximus (by 0.63 ± 1.13 %MVIC; p = 0.023) electromyographic activity for the hamstring-injured side but no significant differences other than a decrease in multifidus activity (by 1.36 ± 2.92 %MVIC; p = 0.023) were evident for healthy participants while wearing the PCB. However, the effect sizes for these findings were small. Wearing the PCB did not significantly change electromyographic activity of other muscles in either participant group (p > 0.050). Moreover, the magnitude of change induced by the PCB was not significantly different between groups (p > 0.050) for the investigated muscles. Thus, application of a PCB to decrease electromyographic activity of injured hamstrings during BUS is likely to have little effect. Similar research is warranted in participants with acute hamstring injury. PMID:25466292

  3. Do Ankle Orthoses Improve Ankle Proprioceptive Thresholds or Unipedal Balance in Older Persons with Peripheral Neuropathy?

    PubMed Central

    Son, Jaebum; Ashton-Miller, James A.; Richardson, James K.

    2010-01-01

    Objective To determine whether ankle orthoses that provide medial and lateral support, and have been found to decrease gait variability in older persons with peripheral neuropathy, decrease (improve) frontal plane ankle proprioceptive thresholds or increase unipedal stance time in that same population. Design Observational study in which unipedal stance time was determined with a stopwatch, and frontal plane ankle (inversion and eversion) proprioceptive thresholds were quantified during bipedal stance with and without the ankle orthoses, in 11 older diabetic subjects with peripheral neuropathy (8 men; age 72 ± 7.1 years) using a foot cradle system which presented a series of 100 rotational stimuli. Results The subjects demonstrated no change in combined frontal plane (inversion + eversion) proprioceptive thresholds or unipedal stance time with versus without the orthoses (1.06 ± 0.56 versus 1.13 ± 0.39 degrees, respectively; p = 0.955 and 6.1 ± 6.5 versus 6.2 ± 5.4 seconds, respectively; p = 0.922). Conclusion Ankle orthoses which provide medial-lateral support do not appear to change ankle inversion/eversion proprioceptive thresholds or unipedal stance time in older persons with diabetic peripheral neuropathy. Previously identified improvements in gait variability using orthoses in this population are therefore likely related to an orthotically-induced stiffening of the ankle rather than a change in ankle afferent function. PMID:20407302

  4. Frontal plane ankle proprioceptive thresholds and unipedal balance

    PubMed Central

    Son, Jaebum; Ashton-Miller, James A.; Richardson, James K.

    2012-01-01

    Reliable unipedal balance is fundamental to safe ambulation. Accordingly, older persons with peripheral neuropathy (PN), who are at increased risk for falls, demonstrate impaired unipedal balance. To explore the relationship between afferent function and unipedal balance, frontal plane proprioceptive thresholds at the ankle were quantified in 22 subjects (72.5 ± 6.3 years; 11 with PN and 11 matched controls) while they were standing using a foot cradle system and a staircase series of 100 rotational stimuli. PN subjects, as compared to controls, demonstrated shorter median unipedal balance times (3.4 ± 2.7 versus 14.3 ± 8.9 seconds; p = 0.0017) and greater (less precise) combined ankle inversion/eversion proprioceptive thresholds (1.17 ± 0.36 versus 0.65 ± 0.37 degrees; p = 0.0055). Combined ankle inversion/eversion proprioceptive thresholds explained approximately half the variance in unipedal balance time (R2 = 0.5138; p = 0.0004). Given prior work demonstrating a similarly strong relationship between ankle torque generation and unipedal balance, neuropathy-associated impairments in ankle frontal plane afferent and efferent function appear to be equally responsible for the inability of older persons with PN to reliably balance on one foot. They therefore provide distinct targets for intervention. PMID:19145650

  5. Unipedal Postural Balance and Countermovement Jumps After a Warm-up and Plyometric Training Session: A Randomized Controlled Trial.

    PubMed

    Romero-Franco, Natalia; Jiménez-Reyes, Pedro

    2015-11-01

    The purpose of this study was to analyze the immediate effects of a plyometric training protocol on unipedal postural balance and countermovement jumps. In addition, we analyzed the effects of a warm-up on these parameters. Thirty-two amateur male sprinters (24.9 ± 4.1 years; 72.3 ± 10.7 kg; 1.78 ± 0.05 m; 22.6 ± 3.3 kg·m) were randomly sorted into a control group (n = 16) (they did not perform any physical activity) and a plyometric training group (n = 16) (they performed a 15-minute warm-up and a high-intensity plyometric protocol consisting of 10 sets of 15 vertical jumps). Before and after the warm-up, and immediately after and 5 minutes after the plyometric protocol, all athletes indicated the perceived exertion on calf and quad regions on a scale from 0 (no exertion) to 10 (maximum exertion). They also carried out a maximum countermovement jump and a unipedal postural balance test (athletes would remain as still as possible for 15 seconds in a left leg and right leg support stance). Results showed that, in the plyometric group, length and velocity of center-of-pressure movement in right leg support stance increased compared with baseline (p = 0.001 and p = 0.004, respectively) and to the control group (p = 0.035 and p = 0.029, respectively) immediately after the plyometric protocol. In addition, the countermovement jump height decreased right after the plyometric protocol (p < 0.001). The perceived exertion on calf and quad regions increased after the plyometry (p < 0.001). Five minutes later, these parameters remained deteriorated despite a slight recovery (length: p = 0.044; velocity: p = 0.05; countermovement jump height: p < 0.001; local exertion: p < 0.001). Data also showed that countermovement jump height improved after the warm-up (p = 0.021), but unipedal postural balance remained unaltered. As a conclusion, high-intensity plyometric exercises blunt unipedal postural balance and countermovement jump performance. The deterioration lasts at least 5 minutes, which may influence future exercises in the training session. Coaches should plan the training routine according to the immediate effects of plyometry on postural balance and vertical jumps, which play a role in injury prevention and sports performance. PMID:26506062

  6. Intensive Abdominal Drawing-In Maneuver After Unipedal Postural Stability in Nonathletes With Core Instability

    PubMed Central

    Lee, Nam G.; You, Joshua (Sung) H.; Kim, Tae H.; Choi, Bong S.

    2015-01-01

    Context: The exact neuromechanical nature and relative contribution of the abdominal drawing-in maneuver (ADIM) to postural instability warrants further investigation in uninjured and injured populations. Objective: To determine the effects of the ADIM on static core and unipedal postural stability in nonathletes with core instability. Design: Controlled laboratory study. Setting: University research laboratory. Patients or Other Participants: A total of 19 nonathletes (4 women: age = 22.3 ± 1.3 years, height = 164.0 ± 1.7 cm, mass = 56.0 ± 4.6 kg; 15 men: age = 24.6 ± 2.8 years, height = 172.6 ± 4.7 cm, mass = 66.8 ± 7.6 kg) with core instability. Intervention(s): Participants received ADIM training with visual feedback 20 minutes each day for 7 days each week over a 2-week period. Main Outcome Measures(s): Core instability was determined using a prone formal test and measured by a pressure biofeedback unit. Unipedal postural stability was determined by measuring the center-of-pressure sway and associated changes in the abdominal muscle-thickness ratios. Electromyographic activity was measured concurrently in the external oblique, erector spinae, gluteus medius, vastus medialis oblique, tibialis anterior, and medial gastrocnemius muscles. Results: All participants initially were unable to complete the formal test. However, after the 2-week ADIM training period, all participants were able to reduce the pressure biofeedback unit by a range of 4 to 10 mm Hg from an initial 70 mm Hg and maintain it at 60 to 66 mm Hg with minimal activation of the external oblique (t18 = 3.691, P = .002) and erector spinae (t18 = 2.823, P = .01) muscles. Monitoring of the pressure biofeedback unit and other muscle activations confirmed that the correct muscle contraction defining the ADIM was accomplished. This core stabilization was well maintained in the unipedal-stance position, as evidenced by a decrease in the center-of-pressure sway measures (t18 range, 3.953–5.775, P < .001), an increased muscle-thickness ratio for the transverse abdominis (t18 = −2.327, P = .03), and a reduction in external oblique muscle activity (t18 = 3.172, P = .005). Conclusions: We provide the first evidence to highlight the positive effects of ADIM training on core and postural stability in nonathletes with core instability. PMID:25531145

  7. Asymmetric balance control between legs for quiet but not for perturbed stance.

    PubMed

    Vieira, Osvaldo; Coelho, Daniel Boari; Teixeira, Luis Augusto

    2014-10-01

    Interlateral performance asymmetry in upright balance control was evaluated in this investigation by comparing unipedal stance on the right versus the left leg. Participants were healthy young adults, hand-foot congruent preference for the right body side. Balance performance was evaluated in unperturbed quiet stance and in the recovery of balance stability following a mechanical perturbation induced by unexpected load release. Evaluation was made under availability of full sensory information, and under deprivation of vision combined with distortion of sensory inputs from the feet soles. Results from perturbed posture revealed that muscular response latency and postural sway were symmetric between the legs. Unipedal stance was more stable when the body was supported on the right as compared with the left leg. No interaction was found between leg and sensory condition. Our findings are interpreted as resulting from specialization of the sensorimotor system controlling the right leg for continuous low-magnitude postural adjustments, while corrections to large-scale stance sway are symmetrically controlled between body sides. PMID:24954557

  8. Time-dependent influence of sensorimotor set on automatic responses in perturbed stance

    NASA Technical Reports Server (NTRS)

    Chong, R. K.; Horak, F. B.; Woollacott, M. H.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    These experiments tested the hypothesis that the ability to change sensorimotor set quickly for automatic responses depends on the time interval between successive surface perturbations. Sensorimotor set refers to the influence of prior experience or context on the state of the sensorimotor system. Sensorimotor set for postural responses was influenced by first giving subjects a block of identical backward translations of the support surface, causing forward sway and automatic gastrocnemius responses. The ability to change set quickly was inferred by measuring the suppression of the stretched antagonist gastrocnemius responses to toes-up rotations causing backward sway, following the translations. Responses were examined under short (10-14 s) and long (19-24 s) inter-trial intervals in young healthy subjects. The results showed that subjects in the long-interval group changed set immediately by suppressing gastrocnemius to 51% of translation responses within the first rotation and continued to suppress them over succeeding rotations. In contrast, subjects in the short-interval group did not change set immediately, but required two or more rotations to suppress gastrocnemius responses. By the last rotation, the short-interval group suppressed gastrocnemius responses to 33%, similar to the long-interval group of 29%. Associated surface plantarflexor torque resulting from these responses showed similar results. When rotation and translation perturbations alternated, however, the short-interval group was not able to suppress gastrocnemius responses to rotations as much as the long-interval group, although they did suppress more than in the first rotation trial after a series of translations. Set for automatic responses appears to linger, from one trial to the next. Specifically, sensorimotor set is more difficult to change when surface perturbations are given in close succession, making it appear as if set has become progressively stronger. A strong set does not mean that responses become larger over consecutive trials. Rather, it is inferred by the extent of difficulty in changing a response when it is appropriate to do so. These results suggest that the ability to change sensorimotor set quickly is sensitive to whether the change is required after a long or a short series of a prior different response, which in turn depends on the time interval between successive trials. Different rate of gastrocnemius suppression to toes-up rotation of the support surface have been reported in previous studies. This may be partially explained by different inter-trial time intervals demonstrated in this study.

  9. Effects of changing stance conditions on anticipatory postural adjustment and reaction time to voluntary arm movement in humans.

    PubMed

    Dietz, V; Kowalewski, R; Nakazawa, K; Colombo, G

    2000-04-15

    1. The effect on reaction time (RT) and anticipatory postural adjustment (APA) of unexpectedly changing stance conditions was studied using a push or pull arm movement task. The aim was to evaluate the modifiability of RT and APA by an external perturbation associated with an automatic compensatory reaction. 2. Subjects standing on a moveable platform were asked to push or pull a rigid handle as quickly and as strongly as possible in response to the 'go-signal', a visual signal from a green or red light-emitting diode. Forward and backward translations of the platform were randomly induced at four time intervals after the go-signal. In some experiments to detect unspecific arousal there were no platform translations but an acoustic signal was given before the go-signal. Surface electromyographic activity (EMG) of upper arm and lower leg muscles was analysed. 3. During the push task both RT and the duration of APA (onset of APA till the force signal indicating hand action) were shorter during backward than during forward translation. During the pull task the effect of platform translations was the reverse. The delay between go-signal and onset of APA remained constant. Consequently, RT and APA became shorter when the platform was translated in the same direction as that in which the upper body was displaced by the push or pull movement, and longer when it was translated in the opposite direction. The effects were maximal when translations were induced 250 ms after the go-signal, but a difference was detected up to 375 ms. 4. Furthermore, with forward and backward platform translations RT was shorter when the translations were induced early rather than late after the go-signal. This was associated with a shortening of the delay between the go-signal and onset of APA, while APA duration remained constant. The shortened RT was in the range of that obtained when an acoustic signal was given just before the go-signal. 5. It is concluded that (i) both the RT and the duration of APA can be modified by a translation of the support surface in a functionally appropriate way by updating the internal representation of the actual stance condition within the central nervous system. Both RT and APA are shortened when the body displacement induced by the push or pull movement and platform translation have the same direction; conversely, an inappropriate translation of the feet requires a greater APA and leads to a longer RT; (ii) both APA and RT are modifiable by platform translation for more than half the time between the go-signal and the focal push or pull movement; (iii) an unspecific effect of platform translation on RT can be identified; it may be mediated by a different neuronal substrate. PMID:10766937

  10. Patterns of muscle activation accompanying transitions in stance during rapid leg flexion.

    PubMed

    Rogers, M W; Pai, Y C

    1993-01-01

    The organization of electromyographic, ground reaction force, and total body kinematic responses accompanying dynamic transitions from bipedal to unipedal stance during rapid leg flexion movements was examined in healthy human subjects. An impulse-momentum model of motion of the centre of body mass (CM) was used to predict the patterns of muscle activation among bilateral hip abductor-adductor muscles with respect to the primary task muscle. The results indicated an intralimb and interlimb coupling of hip muscle activations which preceded and accompanied the leg flexion response and were compatible with contributing to increasing and subsequently reducing momentum of the CM in the frontal plane. Overall, the findings suggested that the coordinative interaction of postural and intended movement components may be a reflection of the mechanical constraints inherent to stance alteration function. PMID:20719626

  11. Exploring individual differences in preschoolers' causal stance.

    PubMed

    Alvarez, Aubry; Booth, Amy E

    2016-03-01

    Preschoolers, as a group, are highly attuned to causality, and this attunement is known to facilitate memory, learning, and problem solving. However, recent work reveals substantial individual variability in the strength of children's "causal stance," as demonstrated by their curiosity about and preference for new causal information. In this study, we explored the coherence and short-term stability of individual differences in children's causal stance. We also began to investigate the origins of this variability, focusing particularly on the potential role of mothers' explanatory talk in shaping the causal stance of their children. Two measures of causal stance correlated with each other, as well as themselves across time. Both also revealed internal consistency of response. The strength of children's causal stance also correlated with mother's responses on the same tasks and the frequency with which mothers emphasized causality during naturalistic joint activities with their children. Implications for theory and practice are discussed. (PsycINFO Database Record PMID:26689761

  12. "The Road to Freedom": How One Salvadoran Youth Takes an Agentive Stance to Narrate the Self across Time and Space

    ERIC Educational Resources Information Center

    McGinnis, Theresa Ann; Garcia, Andrea

    2012-01-01

    In this article, we use narrative theory to analyze and discuss how one Salvadoran youth, Thomas, constructed three different yet overlapping narratives, including a digital story, on his family's movement across borders. We describe how each telling of his narratives is situated in time and space, where Thomas reveals his understandings of…

  13. How providing more or less time to solve a cognitive task interferes with upright stance control; a posturographic analysis on healthy young adults.

    PubMed

    Rougier, Patrice R; Bonnet, Cédrick T

    2016-06-01

    Contrasted postural effects have been reported in dual-task protocols associating balance control and cognitive task that could be explained by the nature and the relative difficulty of the cognitive task and the biomechanical significance of the force platform data. To better assess their respective role, eleven healthy young adults were required to stand upright quietly on a force platform while concomitantly solving mental-calculation or mental-navigation cognitive tasks. Various levels of difficulty were applied by adjusting the velocity rate at which the instructions were provided to the subject according to his/her maximal capacities measured beforehand. A condition without any concomitant cognitive task was added to constitute a baseline behavior. Two basic components, the horizontal center-of-gravity movements and the horizontal difference between center-of-gravity and center-of-pressures were computed from the complex center-of-pressure recorded movements. It was hypothesized that increasing the delay should infer less interaction between postural control and task solution. The results indicate that both mental-calculation and mental-navigation tasks induce reduced amplitudes for the center-of-pressure minus center-of-gravity movements, only along the mediolateral axis, whereas center-of-gravity movements were not affected, suggesting that different circuits are involved in the central nervous system to control these two movements. Moreover, increasing the delays task does not infer any effect for both movements. Since center-of-pressure minus center-of-gravity expresses the horizontal acceleration communicated to the center-of-gravity, one may assume that the control of the latter should be facilitated in dual-tasks conditions, inferring reduced center-of-gravity movements, which is not seen in our results. This lack of effect should be thus interpreted as a modification in the control of these center-of-gravity movements. Taken together, these results emphasized how undisturbed upright stance control can be impacted by mental tasks requiring attention, whatever their nature (calculation or navigation) and their relative difficulty. Depending on the provided instructions, i.e. focusing our attention on body movements or on the opposite diverting this attention toward other objectives, the evaluation of upright stance control capacities might be drastically altered. PMID:26949920

  14. Statistical analysis of quiet stance sway in 2-D.

    PubMed

    Bakshi, Avijit; DiZio, Paul; Lackner, James R

    2014-04-01

    Subjects exposed to a rotating environment that perturbs their postural sway show adaptive changes in their voluntary spatially directed postural motion to restore accurate movement paths but do not exhibit any obvious learning during passive stance. We have found, however, that a variable known to characterize the degree of stochasticity in quiet stance can also reveal subtle learning phenomena in passive stance. We extended Chow and Collins (Phys Rev E 52(1):909-912, 1995) one-dimensional pinned-polymer model (PPM) to two dimensions (2-D) and then evaluated the model's ability to make analytical predictions for 2-D quiet stance. To test the model, we tracked center of mass and centers of foot pressures, and compared and contrasted stance sway for the anterior-posterior versus medio-lateral directions before, during, and after exposure to rotation at 10 rpm. Sway of the body during rotation generated Coriolis forces that acted perpendicular to the direction of sway. We found significant adaptive changes for three characteristic features of the mean square displacement (MSD) function: the exponent of the power law defined at short time scales, the proportionality constant of the power law, and the saturation plateau value defined at longer time scales. The exponent of the power law of MSD at a short time scale lies within the bounds predicted by the 2-D PPM. The change in MSD during exposure to rotation also had a power-law exponent in the range predicted by the theoretical model. We discuss the Coriolis force paradigm for studying postural and movement control and the applicability of the PPM model in 2-D for studying postural adaptation. PMID:24477760

  15. Statistical analysis of quiet stance sway in 2-D

    PubMed Central

    DiZio, Paul; Lackner, James R.

    2014-01-01

    Subjects exposed to a rotating environment that perturbs their postural sway show adaptive changes in their voluntary spatially directed postural motion to restore accurate movement paths but do not exhibit any obvious learning during passive stance. We have found, however, that a variable known to characterize the degree of stochasticity in quiet stance can also reveal subtle learning phenomena in passive stance. We extended Chow and Collins (Phys Rev E 52(1):909–912, 1995) one-dimensional pinned-polymer model (PPM) to two dimensions (2-D) and then evaluated the model’s ability to make analytical predictions for 2-D quiet stance. To test the model, we tracked center of mass and centers of foot pressures, and compared and contrasted stance sway for the anterior–posterior versus medio-lateral directions before, during, and after exposure to rotation at 10 rpm. Sway of the body during rotation generated Coriolis forces that acted perpendicular to the direction of sway. We found significant adaptive changes for three characteristic features of the mean square displacement (MSD) function: the exponent of the power law defined at short time scales, the proportionality constant of the power law, and the saturation plateau value defined at longer time scales. The exponent of the power law of MSD at a short time scale lies within the bounds predicted by the 2-D PPM. The change in MSD during exposure to rotation also had a power-law exponent in the range predicted by the theoretical model. We discuss the Coriolis force paradigm for studying postural and movement control and the applicability of the PPM model in 2-D for studying postural adaptation. PMID:24477760

  16. Using a Stance Corpus to Learn about Effective Authorial Stance-Taking: A Textlinguistic Approach

    ERIC Educational Resources Information Center

    Chang, Peichin

    2012-01-01

    Presenting a persuasive authorial stance is a major challenge for second language (L2) writers in writing academic research. Failure to present an effective authorial stance often results in poor evaluation, which compromises a writer's research potential. This study proposes a "textlinguistic" approach to advanced academic writing to complement a…

  17. Stance-Taking and Stance-Support in Students' Online Forum Discussion

    ERIC Educational Resources Information Center

    Chandrasegaran, Antonia; Kong, Kah Mun Clara

    2006-01-01

    Stance-taking and stance-support are two discourse behaviours that define the expository/argumentative essay genre, the mastery of which is the key to academic success in higher education. The aim of this study is to discover the extent to which a group of high school students from a non-native English-speaking background are capable of engaging…

  18. Exploring Individual Differences in Preschoolers' Causal Stance

    ERIC Educational Resources Information Center

    Alvarez, Aubry; Booth, Amy E.

    2016-01-01

    Preschoolers, as a group, are highly attuned to causality, and this attunement is known to facilitate memory, learning, and problem solving. However, recent work reveals substantial individual variability in the strength of children's "causal stance," as demonstrated by their curiosity about and preference for new causal information. In…

  19. Five Stances That Have Got to Go

    ERIC Educational Resources Information Center

    Zeigler, Earle F.

    1973-01-01

    The five stances in physical education that have to go are as follows: a) the shotgun approach'' to professional preparation; b) the athletics uber alles approach''; c) the women are all right in their place approach''; d) the body of knowledge approach'' and the password is treadmill' approach.''

  20. Stance in Spoken and Written University Registers

    ERIC Educational Resources Information Center

    Biber, Douglas

    2006-01-01

    Numerous studies have investigated the linguistic expression of stance and evaluation in university registers, focusing especially on academic research writing and to a lesser extent classroom teaching. The present study extends previous research in two ways: (1) it compares and contrasts the use of a wide range of lexico-grammatical features used…

  1. Narrative Stance in the Douglass Autobiographies.

    ERIC Educational Resources Information Center

    Davidson, Phebe

    To consider Frederick Douglass as an autobiographer, it is useful to examine each of his three autobiographical texts with a view to drawing some conclusion about their relation to one another, and about the relation of the author to each one. It seems likely that the shifting of Douglass' narrative stance is an index of his intellectual…

  2. Effects of stance angle on postural stability and performance with national-standard air pistol competitors.

    PubMed

    Hawkins, Richard Nelson

    2013-01-01

    The effects of stance angle on postural stability and shooting processes were studied using eight national-standard male air-pistol shooters. Each shooter performed 60 shots each in four stance angles (0°, 15°, 30° and 45° from the line of fire). Postural stability was determined by measuring change in centre of pressure with a dual-force platform system assessing centre-of-pressure (COP) excursion (average difference of the centre of pressure from the mean) and COP speed (total COP path divided by time). Shooting process measures were determined by using a NOPTEL ST-2000 optoelectronic system. Score was assessed with a Sius Ascor S10 electronic scoring system. The results revealed no significant difference among the various stance angles; COP excursion or COP speed, p>0.05. Results indicated a significant stance angle effect with the shooting process measure, hit fine (percentage of hold within an area the size of the 10-ring when centred over the actual shot; p = 0.025) and the shooting performance measure adjusted score (raw score adjusted for true zero; p=0.008). Moreover, best overall performance was with a stance angle of 15°. These findings suggest that stance angle may affect pistol stability and performance in air-pistol athletes. PMID:24050465

  3. A study on effects of and stance over tuition fees

    PubMed Central

    Karay, Yassin; Matthes, Jan

    2016-01-01

    Aim: Regarding tuition fees (that in Germany already have been abrogated) putative drawbacks like prolonged study duration have been suspected while benefits are not clearly proven. We investigated whether tuition fees (500 Euro per semester) affected the course of studies of Cologne medical students and asked for students’ stance over tuition fees. Methods: Of 1,324 students we analyzed the rate of those passing their first medical exam (“Physikum”) within minimum time and students’ discontinuation rate, respectively. Regression analysis tested for putative influences of tuition fees and demographic factors. In an additional online survey 400 students answered questions regarding the load by and their stance over tuition fees. Results: We find that fees did not affect rate of Cologne students passing their first medical exam within minimum time or students’ discontinuation rate. According to the online survey, at times of tuition fees significantly more students did not attend courses as scheduled. Time spent on earning money was significantly increased. 51% of students who had to pay tuition fees and 71% of those who never had to stated tuition fees to be not justified. More than two thirds of students did not recognize any lasting benefit from tuition fees. Conclusion: Tuition fees did not affect discontinuation rate or study duration of Cologne medical students. However, they obviously influenced the study course due to an increased need to pursue a sideline. Cologne medical students rather refused tuition fees and did not recognize their advantages in terms of enhanced quality of studies. PMID:26958654

  4. The Effects of Argument Stance on Scientific Knowledge Inquiry Skills

    ERIC Educational Resources Information Center

    Horng, Ruey-Yun; Lu, Po-Hui; Chen, Pei-Hua; Hou, Shih-Huan

    2013-01-01

    This study investigates the effects of argument stance on knowledge inquiry skills. Sixty-two participants were assigned to three argument stance conditions (proponent, opponent, or control) to receive scaffolded argumentation practice on two science issues in random order. After the argumentation treatment, participants were asked to write down…

  5. Stance, Navigation, and Reader Response in Expository Hypertext

    ERIC Educational Resources Information Center

    McEneaney, John E.; Li, Ledong; Allen, Kris; Guzniczak, Lizabeth

    2009-01-01

    This article reports on two studies investigating reader stance, navigation, and response in expository hypertext. Subjects in the studies included 69 and 147 adult readers prompted to adopt either an efferent or aesthetic stance when reading a 36-node expository hypertext. Reading was followed by recall and essay writing tasks. Results of the

  6. Soleus H-reflex modulation during receive stance in badminton players in the receive stance

    PubMed Central

    Masu, Yujiro; Muramatsu, Ken

    2015-01-01

    [Purpose] This study aimed to clarify the characteristics of motor neuron excitability by examining the soleus H-reflex in the ready position adopted immediately before making a return during badminton games. [Subjects] Sixteen individuals with (badminton group) and 16 without (control group) experience of playing badminton were studied. [Methods] Each subject was instructed to take up various stances for returning a shuttlecock to measure the H- and M-waves in the soleus. [Results] The H-wave was significantly decreased when gripping a racket was held in the dominant hand than compared to just standing in the badminton group. In contrast, in the control group, no significant differences were observed between when standing and the other stances. [Conclusion] Based on these results, the excitability of spinal motor neurons may have been reduced (H-wave suppression) by badminton training to increase the instantaneous force (power training). PMID:25642054

  7. Soleus H-reflex modulation during receive stance in badminton players in the receive stance.

    PubMed

    Masu, Yujiro; Muramatsu, Ken

    2015-01-01

    [Purpose] This study aimed to clarify the characteristics of motor neuron excitability by examining the soleus H-reflex in the ready position adopted immediately before making a return during badminton games. [Subjects] Sixteen individuals with (badminton group) and 16 without (control group) experience of playing badminton were studied. [Methods] Each subject was instructed to take up various stances for returning a shuttlecock to measure the H- and M-waves in the soleus. [Results] The H-wave was significantly decreased when gripping a racket was held in the dominant hand than compared to just standing in the badminton group. In contrast, in the control group, no significant differences were observed between when standing and the other stances. [Conclusion] Based on these results, the excitability of spinal motor neurons may have been reduced (H-wave suppression) by badminton training to increase the instantaneous force (power training). PMID:25642054

  8. Effect of stance width on multidirectional postural responses

    NASA Technical Reports Server (NTRS)

    Henry, S. M.; Fung, J.; Horak, F. B.; Peterson, B. W. (Principal Investigator)

    2001-01-01

    The effect of stance width on postural responses to 12 different directions of surface translations was examined. Postural responses were characterized by recording 11 lower limb and trunk muscles, body kinematics, and forces exerted under each foot of 7 healthy subjects while they were subjected to horizontal surface translations in 12 different, randomly presented directions. A quasi-static approach of force analysis was done, examining force integrals in three different epochs (background, passive, and active periods). The latency and amplitude of muscle responses were quantified for each direction, and muscle tuning curves were used to determine the spatial activation patterns for each muscle. The results demonstrate that the horizontal force constraint exerted at the ground was lessened in the wide, compared with narrow, stance for humans, a similar finding to that reported by Macpherson for cats. Despite more trunk displacement in narrow stance, there were no significant changes in body center of mass (CoM) displacement due to large changes in center of pressure (CoP), especially in response to lateral translations. Electromyographic (EMG) magnitude decreased for all directions in wide stance, particularly for the more proximal muscles, whereas latencies remained the same from narrow to wide stance. Equilibrium control in narrow stance was more of an active postural strategy that included regulating the loading/unloading of the limbs and the direction of horizontal force vectors. In wide stance, equilibrium control relied more on an increase in passive stiffness resulting from changes in limb geometry. The selective latency modulation of the proximal muscles with translation direction suggests that the trunk was being actively controlled in all directions. The similar EMG latencies for both narrow and wide stance, with modulation of only the muscle activation magnitude as stance width changed, suggest that the same postural synergy was only slightly modified for a change in stance width. Nevertheless, the magnitude of the trunk displacement, as well as of CoP displacement, was modified based on the degree of passive stiffness in the musculoskeletal system, which increased with stance width. The change from a more passive to an active horizontal force constraint, to larger EMG magnitudes especially in the trunk muscles and larger trunk and CoP excursions in narrow stance are consistent with a more effortful response for equilibrium control in narrow stance to perturbations in all directions.

  9. Quiet stance control is affected by prior treadmill but not overground locomotion.

    PubMed

    Zanetti, Carlo; Schieppati, Marco

    2007-06-01

    Treadmill locomotion is different with respect to overground walking and may require an adapted control mode. The relevant neural computational effort may produce lasting effects encroaching upon the performance of a subsequent postural task. The hypothesis of the present study was that, contrary to overground walking, treadmill walking has effects on quiet stance variables, in the assumption that the imposed locomotor activity is more critical to stance control than natural walking. Nine young subjects performed three different walking sessions: treadmill with eyes closed, treadmill with eyes open, overground walking with eyes open. Body sway area and sway path and the position of the centre of foot pressure during stance were recorded by a dynamometric platform under control, post-walking and post-recovery conditions, alternatively with eyes closed and eyes open. At variance with overground walking, treadmill locomotion produced an effect on body orientation in space during the subsequent stance trials. This consisted in a forward inclination of the body, not accompanied by increased body sway, lasting for a few minutes. Presence or absence of vision during treadmill locomotion did not induce differences in the amplitude or time-course of the post-effect. We argue that body inclination would be the consequence of a change in the postural reference produced by a message arising from treadmill locomotion itself, possibly connected to particularities in the control mode of this type of walking. PMID:17357791

  10. Body stability and muscle and motor cortex activity during walking with wide stance.

    PubMed

    Farrell, Brad J; Bulgakova, Margarita A; Beloozerova, Irina N; Sirota, Mikhail G; Prilutsky, Boris I

    2014-08-01

    Biomechanical and neural mechanisms of balance control during walking are still poorly understood. In this study, we examined the body dynamic stability, activity of limb muscles, and activity of motor cortex neurons [primarily pyramidal tract neurons (PTNs)] in the cat during unconstrained walking and walking with a wide base of support (wide-stance walking). By recording three-dimensional full-body kinematics we found for the first time that during unconstrained walking the cat is dynamically unstable in the forward direction during stride phases when only two diagonal limbs support the body. In contrast to standing, an increased lateral between-paw distance during walking dramatically decreased the cat's body dynamic stability in double-support phases and prompted the cat to spend more time in three-legged support phases. Muscles contributing to abduction-adduction actions had higher activity during stance, while flexor muscles had higher activity during swing of wide-stance walking. The overwhelming majority of neurons in layer V of the motor cortex, 82% and 83% in the forelimb and hindlimb representation areas, respectively, were active differently during wide-stance walking compared with unconstrained condition, most often by having a different depth of stride-related frequency modulation along with a different mean discharge rate and/or preferred activity phase. Upon transition from unconstrained to wide-stance walking, proximal limb-related neuronal groups subtly but statistically significantly shifted their activity toward the swing phase, the stride phase where most of body instability occurs during this task. The data suggest that the motor cortex participates in maintenance of body dynamic stability during locomotion. PMID:24790167

  11. Negotiating treatment preferences: Physicians' formulations of patients' stance.

    PubMed

    Landmark, Anne Marie Dalby; Svennevig, Jan; Gulbrandsen, Pål

    2016-01-01

    Eliciting patients' values and treatment preferences is an essential element in models of shared decision making, yet few studies have investigated the interactional realizations of how physicians do this in authentic encounters. Drawing on video-recorded encounters from Norwegian secondary care, the present study uses the fine-grained empirical methodology of conversation analysis (CA) to identify one conversational practice physicians use, namely, formulations of patients' stance, in which physicians summarize or paraphrase their understanding of the patient's stance towards treatment. The purpose of this study is twofold: (1) to explore what objectives formulations of patients' stance achieve while negotiating treatment and (2) to discuss these objectives in relation to core requirements in shared decision making. Our analysis demonstrates that formulating the patient's stance is a practice physicians use in order to elicit, check, and establish patients' attitudes towards treatment. This practice is in line with general recommendations for making shared decisions, such as exploring and checking patients' preferences and values. However, the formulations may function as a device for doing more than merely checking and establishing common ground and bringing up patients' preferences and views: Accompanied by subtle deprecating expressions, they work to delegitimize the patients' stances and indirectly convey the physicians' opposing stance. Once established, these positions can be used as a basis for challenging and potentially altering the patient's attitude towards the decision, thereby making it more congruent with the physician's view. Therefore, in addition to bringing up patients' views towards treatment, we argue that physicians may use formulations of patients' stance as a resource for directing the patient towards decisions that are congruent with the physician's stance in situations with potential disagreement, whilst (ostensibly) avoiding a more authoritarian or paternalistic approach. PMID:26699275

  12. Detecting Underlying Stance Adopted When Human Construe Behavior of Entities

    NASA Astrophysics Data System (ADS)

    Terada, Kazunori; Ono, Kouhei; Ito, Akira

    Whether or not humans can construe the behaviors of entities depends on their psychological stance. The philosopher Dennett proposed human cognitive strategies (three stances) in which humans construe the behavior of other animated objects, including other humans, artifacts, and physical phenomena:‘intentional’, ‘design’ and ‘physical’ stances. Detecting the psychological stance taken toward entities is difficult, because such mental state attribution is a subjective cognitive process and hard to measure. In the present study, we proposed a novel method for detecting underlying stance adopted when human construe behavior of entities. In our method the subject was asked to select the most suitable action sequence shown in three movies each of which representing Dennett’s three stances. To valid our method we have conducted an experiment in which the subjects were presented thirty short videos and asked to compare them to the three movies. The result indicated that the subjects did not focused on prior knowledge about the entity but could focused on motion characteristics per se, owing to simple and typical motion of an abstract shaped object.

  13. EMG responses to maintain stance during multidirectional surface translations

    NASA Technical Reports Server (NTRS)

    Henry, S. M.; Fung, J.; Horak, F. B.; Peterson, B. W. (Principal Investigator)

    1998-01-01

    To characterize muscle synergy organization underlying multidirectional control of stance posture, electromyographic activity was recorded from 11 lower limb and trunk muscles of 7 healthy subjects while they were subjected to horizontal surface translations in 12 different, randomly presented directions. The latency and amplitude of muscle responses were quantified for each perturbation direction. Tuning curves for each muscle were examined to relate the amplitude of the muscle response to the direction of surface translation. The latencies of responses for the shank and thigh muscles were constant, regardless of perturbation direction. In contrast, the latencies for another thigh [tensor fascia latae (TFL)] and two trunk muscles [rectus abdominis (RAB) and erector spinae (ESP)] were either early or late, depending on the perturbation direction. These three muscles with direction-specific latencies may play different roles in postural control as prime movers or as stabilizers for different translation directions, depending on the timing of recruitment. Most muscle tuning curves were within one quadrant, having one direction of maximal activity, generally in response to diagonal surface translations. Two trunk muscles (RAB and ESP) and two lower limb muscles (semimembranosus and peroneus longus) had bipolar tuning curves, with two different directions of maximal activity, suggesting that these muscle can play different roles as part of different synergies, depending on translation direction. Muscle tuning curves tended to group into one of three regions in response to 12 different directions of perturbations. Two muscles [rectus femoris (RFM) and TFL] were maximally active in response to lateral surface translations. The remaining muscles clustered into one of two diagonal regions. The diagonal regions corresponded to the two primary directions of active horizontal force vector responses. Two muscles (RFM and adductor longus) were maximally active orthogonal to their predicted direction of maximal activity based on anatomic orientation. Some of the muscles in each of the synergic regions were not anatomic synergists, suggesting a complex central organization for recruitment of muscles. The results suggest that neither a simple reflex mechanism nor a fixed muscle synergy organization is adequate to explain the muscle activation patterns observed in this postural control task. Our results are consistent with a centrally mediated pattern of muscle latencies combined with peripheral influence on muscle magnitude. We suggest that a flexible continuum of muscle synergies that are modifiable in a task-dependent manner be used for equilibrium control in stance.

  14. Direct corticospinal pathways contribute to neuromuscular control of perturbed stance.

    PubMed

    Taube, Wolfgang; Schubert, Martin; Gruber, Markus; Beck, Sandra; Faist, Michael; Gollhofer, Albert

    2006-08-01

    The antigravity soleus muscle (Sol) is crucial for compensation of stance perturbation. A corticospinal contribution to the compensatory response of the Sol is under debate. The present study assessed spinal, corticospinal, and cortical excitability at the peaks of short- (SLR), medium- (MLR), and long-latency responses (LLR) after posterior translation of the feet. Transcranial magnetic stimulation (TMS) and peripheral nerve stimulation were individually adjusted so that the peaks of either motor evoked potential (MEP) or H reflex coincided with peaks of SLR, MLR, and LLR, respectively. The influence of specific, presumably direct, corticospinal pathways was investigated by H-reflex conditioning. When TMS was triggered so that the MEP arrived in the Sol at the same time as the peaks of SLR and MLR, EMG remained unaffected. Enhanced EMG was observed when the MEP coincided with the LLR peak (P < 0.001). Similarly, conditioning of the H reflex by subthreshold TMS facilitated H reflexes only at LLR (P < 0.001). The earliest facilitation after perturbation occurred after 86 ms. The TMS-induced H-reflex facilitation at LLR suggests that increased cortical excitability contributes to the augmentation of the LLR peaks. This provides evidence that the LLR in the Sol muscle is at least partly transcortical, involving direct corticospinal pathways. Additionally, these results demonstrate that approximately 86 ms after perturbation, postural compensatory responses are cortically mediated. PMID:16601305

  15. A new method to assess passive and active ankle stiffness during quiet upright stance.

    PubMed

    Zhang, Hongbo; Nussbaum, Maury A; Agnew, Michael J

    2015-12-01

    Both passive and active ankle torque contribute to postural stability during quiet upright stance, yet directly measuring their relative contributions is difficult. Here, a new method was developed to estimate passive and active ankle stiffness (ST) and damping (DA). In contrast to earlier approaches, the proposed method does not require external mechanical or sensory perturbations. Instead, the method is based on the assumption that upright stance is intermittently controlled, and that active ankle torque is in-phase coherent with ankle angular acceleration. Thus, identifying the local maxima of ankle angular accelerations facilitates the identification of time windows that include substantial active ankle torque. After identifying these local maxima and associated windows, estimates of passive and active ankle ST and DA were obtained using linear regression analyses. Consistent with earlier work, passive ankle torque was estimated to account for 94-97% of the total ankle torque, and to have linear relationships with ankle angle and angular velocity. Predicted values of passive and active ankle stiffness were also consistent with earlier reports. This new approach may be a useful tool to efficiently investigate passive and active joint stiffness during quiet upright stance. PMID:26547842

  16. Angular-velocity control approach for stance-control orthoses.

    PubMed

    Lemaire, Edward D; Goudreau, Louis; Yakimovich, Terris; Kofman, Jonathan

    2009-10-01

    Currently, stance-control knee orthoses require external control mechanisms to control knee flexion during stance and allow free knee motion during the swing phase of gait. A new angular-velocity control approach that uses a rotary-hydraulic device to resist knee flexion when the knee angular velocity passes a preset threshold is presented. This angular-velocity approach for orthotic stance control is based on the premise that knee-flexion angular velocity during a knee-collapse event, such as a stumble or fall, is greater than that during walking. The new hydraulic knee-flexion control device does not require an external control mechanism to switch from free motion to stance control mode. Functional test results demonstrated that the hydraulic angular-velocity activated knee joint provided free knee motion during walking, engaged upon knee collapse, and supported body weight while the end-user recovered to a safe body position. The joint was tested to 51.6 Nm in single loading tests and passed 200,000 repeated loading cycles with a peak load of 88 Nm per cycle. The hydraulic, angular velocity activation approach has potential to improve safety and security for people with lower extremity weakness or when recovering from joint trauma. PMID:19497821

  17. Attributes of quiet stance in the chronic spinal cat.

    PubMed

    Fung, J; Macpherson, J M

    1999-12-01

    Standing is a dynamic task that requires antigravity support of the body mass and active regulation of the position of the body center of mass. This study examined the extent to which the chronic spinal cat can maintain postural orientation during stance and adapt to changes in stance distance (fore-hindpaw separation). Intact cats adapt to changes in stance distance by maintaining a constant horizontal orientation of the trunk and changing orientation of the limbs, while keeping intralimb geometry constant and aligning the ground reaction forces closely with the limb axes. Postural adaptation was compared in four cats before and after spinalization at the T(6) level, in terms of the forces exerted by each paw against the support, body geometry (kinematics) and electromyographic (EMG) activity recorded from chronic, indwelling electrodes, as well as the computed net torques in the fore and hindlimbs. Five fore-hindpaw distances spanning the preferred distance were tested before spinalization, with a total range of 20 cm from the shortest to the longest stance. After spinalization, the cats were trained on a daily basis to stand on the force platform, and all four cats were able to support their full body weight. Three of the four cats could adapt to changes in stance distance, but the range was smaller and biased toward the shorter distances. The fourth cat could stand only at one stance distance, which was 8 cm shorter than the preferred distance before spinalization. All cats shifted their center of pressure closer to the forelimbs after spinalization, but the amount of shift could largely be accounted for by the weight loss in the hindquarters. The three cats that could adapt to changes in stance distance used a similar strategy as the intact cat by constraining the trunk and changing orientation of the limb axes in close relation with the forces exerted by each limb. However, different postures in the fore- and hindlimbs were adopted, particularly at the scapula (more extended) and pelvis (tipped more anteriorly). Other changes from control included a redistribution of net extensor torque across the joints of the forelimb and of the hindlimb. We concluded that the general form of body axis orientation is relatively conserved in the spinal cat, suggesting that the lumbosacral spinal circuitry includes rudimentary set points for hindlimb geometry. Both mechanical and neural elements can contribute toward maintaining body geometry through stiffness regulation and spinal reflexes. PMID:10601441

  18. Observational stance as a predictor of subjective and genital sexual arousal in men and women.

    PubMed

    Bossio, Jennifer A; Spape, Jessica; Lykins, Amy D; Chivers, Meredith L

    2014-01-01

    Observational stance refers to the perspective a person takes while viewing a sexual stimulus, either as a passive observer (observer stance) or an active participant (participant stance). The objective of the current study was to examine the relationship between observational stance and sexual arousal (subjective and genital) across a range of sexual stimuli that do or do not correspond with a participant's sexual attraction (preferred or nonpreferred stimuli, respectively). Regression analyses revealed that, for men (n = 44), participant stance significantly predicted subjective and genital arousal. Women's (n = 47) observer and participant stance predicted subjective arousal but not genital arousal. Analysis of variance showed that participant stance was greatest under preferred sexual stimuli conditions for all groups of participants, while observer stance scores revealed a less consistent pattern of response. This was particularly true for opposite-sex-attracted women, whose ratings of observer stance were lowest for preferred stimuli. Observational stance does not appear to account for gender differences in specificity of sexual arousal; for men, however, participant stance uniquely predicted genital response after controlling for sexual attractions. Similarities in the relationships between men's and women's observational stance and sexual responses challenge previous claims of gender differences in how men and women view erotica. PMID:23514448

  19. Situating Reader Stance within and beyond the Efferent-Aesthetic Continuum

    ERIC Educational Resources Information Center

    Paulson, Eric J.; Armstrong, Sonya L.

    2010-01-01

    The purpose of this theoretical essay is to encourage critical reflection of the relationship of specific reading events to traditional conceptualizations of reader stance. While conventional models of reader stance are useful for considering many aspects of reading, there are reading events that engender stances that appear to lie outside of the…

  20. Perceptions of Same-Versus Cross-Sex-Typed Physical Stance.

    ERIC Educational Resources Information Center

    Fling, Sheila; And Others

    1986-01-01

    Undergraduates (N=75) did semantic differential ratings on four pictures: a male or female in a "masculine" or "feminine" stance. The "masculine" stance was perceived as more masculine, potent, happy, and well-adjusted than the "feminine" stance. Cross-sex-typed males were rated less favorably and cross-sex-typed females more favorably than their

  1. Balance in Astronauts Performing Jumps, Walking and Quiet Stance Following Spaceflight

    NASA Technical Reports Server (NTRS)

    Reschke, Millard F.; Bloomberg, J. J.; Wood, S. J.; Harm, D. L.

    2011-01-01

    Introduction: Both balance and locomotor ataxia is severe in astronauts returning from spaceflight with serious implications for unassisted landings. As a part of an ongoing effort to demonstrate the functional significance of the postflight ataxia problem our laboratory has evaluated jumping, walking heel-to-toe and quite stance balance immediately following spaceflight. Methods: Six astronauts from 12-16 day flights and three from 6-month flights were asked to perform three self-initiated two-footed jumps from a 30-cm-high platform, walking for 10 steps (three trials) placing the feet heel to toe in tandem, arms folded across the chest and the eyes closed, and lastly, recover from a simulated fall by standing from a prone position on the floor and with eyes open maintain a quiet stance for 3 min with arms relaxed along the side of the body and feet comfortably positioned on a force plate. Crewmembers were tested twice before flight, on landing day (short-duration), and days 1, 6, and 30 following all flight durations. Results/Conclusions: Many of astronauts tested fell on their first postflight jump but recovered by the third jump showing a rapid learning progression. Changes in take-off strategy were clearly evident in duration of time in the air between the platform and the ground (significant reduction in time to land), and also in increased asymmetry in foot latencies on take-off postflight. During the tandem heel-to-toe walking task there was a significant decrease in percentage of correct steps on landing day (short-duration crew) and on first day following landing (long-duration) with only partial recovery the following day. Astronauts for both short and long duration flight times appeared to be unaware of foot position relative to their bodies or the floor. During quite stance most of crewmembers tested exhibited increased stochastic activity (larger short-term COP diffusion coefficients postflight in all planes and increases in mean sway speed).

  2. The analyst's stance and the method of free association.

    PubMed

    Kris, A O

    1990-01-01

    The concept of the analyst's stance is employed to organize a number of ideas about psychoanalytic work, past and present, especially from the viewpoint of the method of free association. Beginning with an emphasis on the intrinsic uncertainties and paradoxes of the analytic process, the author reviews the importance of words, the aim of mastering resistances (i.e., promoting freedom of association), and functional neutrality on the analyst's part. The problem of anonymity is considered from a number of angles. Two traditions of transference are described, deriving from Freud's overlapping early formulations. The distinction between old and new determinants in the two kinds of transference is useful and important in the analyst's stance. Attitudes toward insight, resistance, and conflict resolution are considered from the perspective of the distinction between divergent and convergent conflicts, with special emphasis on the role of punitive, unconscious self-criticism. PMID:2251309

  3. A robotic cadaveric flatfoot analysis of stance phase.

    PubMed

    Jackson, Lyle T; Aubin, Patrick M; Cowley, Matthew S; Sangeorzan, Bruce J; Ledoux, William R

    2011-05-01

    The symptomatic flatfoot deformity (pes planus with peri-talar subluxation) can be a debilitating condition. Cadaveric flatfoot models have been employed to study the etiology of the deformity, as well as invasive and noninvasive surgical treatment strategies, by evaluating bone positions. Prior cadaveric flatfoot simulators, however, have not leveraged industrial robotic technologies, which provide several advantages as compared with the previously developed custom fabricated devices. Utilizing a robotic device allows the researcher to experimentally evaluate the flatfoot model at many static instants in the gait cycle, compared with most studies, which model only one to a maximum of three instances. Furthermore, the cadaveric tibia can be statically positioned with more degrees of freedom and with a greater accuracy, and then a custom device typically allows. We created a six degree of freedom robotic cadaveric simulator and used it with a flatfoot model to quantify static bone positions at ten discrete instants over the stance phase of gait. In vivo tibial gait kinematics and ground reaction forces were averaged from ten flatfoot subjects. A fresh frozen cadaveric lower limb was dissected and mounted in the robotic gait simulator (RGS). Biomechanically realistic extrinsic tendon forces, tibial kinematics, and vertical ground reaction forces were applied to the limb. In vitro bone angular position of the tibia, calcaneus, talus, navicular, medial cuneiform, and first metatarsal were recorded between 0% and 90% of stance phase at discrete 10% increments using a retroreflective six-camera motion analysis system. The foot was conditioned flat through ligament attenuation and axial cyclic loading. Post-flat testing was repeated to study the pes planus deformity. Comparison was then made between the pre-flat and post-flat conditions. The RGS was able to recreate ten gait positions of the in vivo pes planus subjects in static increments. The in vitro vertical ground reaction force was within ± 1 standard deviation (SD) of the in vivo data. The in vitro sagittal, coronal, and transverse plane tibial kinematics were almost entirely within ± 1 SD of the in vivo data. The model showed changes consistent with the flexible flatfoot pathology including the collapse of the medial arch and abduction of the forefoot, despite unexpected hindfoot inversion. Unlike previous static flatfoot models that use simplified tibial degrees of freedom to characterize only the midpoint of the stance phase or at most three gait positions, our simulator represented the stance phase of gait with ten discrete positions and with six tibial degrees of freedom. This system has the potential to replicate foot function to permit both noninvasive and surgical treatment evaluations throughout the stance phase of gait, perhaps eliciting unknown advantages or disadvantages of these treatments at other points in the gait cycle. PMID:21599096

  4. The cat vertebral column: stance configuration and range of motion

    NASA Technical Reports Server (NTRS)

    Macpherson, J. M.; Ye, Y.; Peterson, B. W. (Principal Investigator)

    1998-01-01

    This study examined the configuration of the vertebral column of the cat during independent stance and in various flexed positions. The range of motion in the sagittal plane is similar across most thoracic and lumbar joints, with the exception of a lesser range at the transition region from thoracic-type to lumbar-type vertebrae. The upper thoracic column exhibits most of its range in dorsiflexion and the lower thoracic and lumbar in ventroflexion. Lateral flexion is limited to less than 5 degrees at all segments. The range in torsion is almost 180 degrees and occurs primarily in the midthoracic region, T4-T11. Contrary to the depiction in most atlases, the standing cat exhibits several curvatures, including a mild dorsiflexion in the lower lumbar segments, a marked ventroflexion in the lower thoracic and upper lumbar segments, and a profound dorsiflexion in the upper thoracic (above T9) and cervical segments. The curvatures are not significantly changed by altering stance distance but are affected by head posture. During stance, the top of the scapula lies well above the spines of the thoracic vertebrae, and the glenohumeral joint is just below the bodies of vertebrae T3-T5. Using a simple static model of the vertebral column in the sagittal plane, it was estimated that the bending moment due to gravity is bimodal with a dorsiflexion moment in the lower thoracic and lumbar region and a ventroflexion moment in the upper thoracic and cervical region. Given the bending moments and the position of the scapula during stance, it is proposed that two groups of scapular muscles provide the major antigravity support for the head and anterior trunk. Levator scapulae and serratus ventralis form the lateral group, inserting on the lateral processes of cervical vertebrae and on the ribs. The major and minor rhomboids form the medial group, inserting on the spinous tips of vertebrae from C4 to T4. It is also proposed that the hypaxial muscles, psoas major, minor, and quadratus lumborum could support the lumbar trunk during stance.

  5. The influence of ankle muscle activation on postural sway during quiet stance.

    PubMed

    Warnica, Meagan J; Weaver, Tyler B; Prentice, Stephen D; Laing, Andrew C

    2014-04-01

    Although balance during quiet standing is postulated to be influenced by multiple factors, including ankle stiffness, it is unclear how different mechanisms underlying increases in stiffness affect balance control. Accordingly, this study examined the influence of muscle activation and passive ankle stiffness increases on the magnitude and frequency of postural sway. Sixteen young adults participated in six quiet stance conditions including: relaxed standing, four muscle active conditions (10%, 20%, 30% and 40% maximum voluntary contraction (MVC)), and one passive condition wearing an ankle foot orthotic (AFO). Kinetics were collected from a force plate, while whole-body kinematics were collected with a 12-sensor motion capture system. Bilateral electromyographic signals were recorded from the tibialis anterior and medial gastrocnemius muscles. Quiet stance sway amplitude (range and root mean square) and frequency (mean frequency and velocity) in the sagittal plane were calculated from time-varying centre of gravity (COG) and centre of pressure (COP) data. Compared to the relaxed standing condition, metrics of sway amplitude were significantly increased (between 37.5 and 63.2%) at muscle activation levels of 30% and 40% MVC. Similarly, frequency measures increased between 30.5 and 154.2% in the 20-40% MVC conditions. In contrast, passive ankle stiffness, induced through the AFO, significantly decreased sway amplitude (by 23-26%), decreased COG velocity by 13.8%, and increased mean COP frequency by 24.9%. These results demonstrate that active co-contraction of ankle musculature (common in Parkinson's Disease patients) may have differential effects on quiet stance balance control compared to the use of an ankle foot orthotic (common for those recovering from stroke). PMID:24613374

  6. Limb-Bone Scaling Indicates Diverse Stance and Gait in Quadrupedal Ornithischian Dinosaurs

    PubMed Central

    Maidment, Susannah C. R.; Linton, Deborah H.; Upchurch, Paul; Barrett, Paul M.

    2012-01-01

    Background The most primitive ornithischian dinosaurs were small bipeds, but quadrupedality evolved three times independently in the clade. The transition to quadrupedality from bipedal ancestors is rare in the history of terrestrial vertebrate evolution, and extant analogues do not exist. Constraints imposed on quadrupedal ornithischians by their ancestral bipedal bauplan remain unexplored, and consequently, debate continues about their stance and gait. For example, it has been proposed that some ornithischians could run, while others consider that none were cursorial. Methodology/Principal Findings Drawing on biomechanical concepts of limb bone scaling and locomotor theory developed for extant taxa, we use the largest dataset of ornithischian postcranial measurements so far compiled to examine stance and gait in quadrupedal ornithischians. Differences in femoral midshaft eccentricity in hadrosaurs and ceratopsids may indicate that hadrosaurs placed their feet on the midline during locomotion, while ceratopsids placed their feet more laterally, under the hips. More robust humeri in the largest ceratopsids relative to smaller taxa may be due to positive allometry in skull size with body mass in ceratopsids, while slender humeri in the largest stegosaurs may be the result of differences in dermal armor distribution within the clade. Hadrosaurs are found to display the most cursorial morphologies of the quadrupedal ornithischian cades, indicating higher locomotor performance than in ceratopsids and thyreophorans. Conclusions/Significance Limb bone scaling indicates that a previously unrealised diversity of stances and gaits were employed by quadrupedal ornithischians despite apparent convergence in limb morphology. Grouping quadrupedal ornithischians together as a single functional group hides this disparity. Differences in limb proportions and scaling are likely due to the possession of display structures such as horns, frills and dermal armor that may have affected the center of mass of the animal, and differences in locomotor behaviour such as migration, predator escape or home range size. PMID:22666333

  7. Stability and the maintenance of balance following a perturbation from quiet stance

    NASA Astrophysics Data System (ADS)

    Stirling, J. R.; Zakynthinaki, M. S.

    2004-03-01

    We investigate stability and the maintenance of balance with the use of tools from dynamical systems. In particular we investigate the application of such tools to the study of the ground reaction forces resulting from an athlete being perturbed from quiet stance. We develop a nonlinear model consisting of a set of coupled vector fields for the derivative with respect to time of the angles between the resultant ground reaction forces and the vertical in the anteroposterior and mediolateral directions. This model contains a basin of attraction bound by a closed curve which we call the critical curve. It is only inside this curve that perturbations can be corrected, with the orbit spiraling onto an attractor corresponding to quiet stance. We show how the critical curve and also the strength of the attractor found in the basin of attraction can be fit to model the experimental data (time series) for an individual athlete. We also discuss how our model can be used to identify nonsymmetric behavior caused by muscle imbalances and differences in the ranges of motion on either side of the body.

  8. Influence of body position on fibularis longus and soleus Hoffmann reflexes.

    PubMed

    Kim, Kyung-Min; Hart, Joseph M; Hertel, Jay

    2013-01-01

    It is widely accepted that Hoffmann (H) reflex amplitudes of the soleus decrease as complexity of body positions increases, but it is not known if this same mechanism of postural control is seen in other ankle muscles such as fibularis longus (FL). Our purpose was to assess if FL H-reflex changed in different body positions and if the adaptations were correlated to soleus H-reflex modulation. Fifteen healthy subjects had their FL and soleus H-reflexes measured in three positions (prone, bipedal, unipedal). Maximal H-reflexes (H-max) and motor responses (M-max) were collected bilaterally. The average H-max and M-max were used to calculate H(max)/M(max) ratios. To control influences of background muscle activity on H-reflex measures, the ratios were normalized to their corresponding mean EMG amplitudes over a 50-ms time epoch. H-reflex amplitudes of both muscles were significantly lower in unipedal stance than other positions. Additionally, there were strong correlations (R(2)>0.7) in H-reflex modulation between the two muscles when transitioning from prone to either bipedal or unipedal stance. Down-modulation of H-reflex when transitioning to unipedal stance was present in both FL and soleus suggesting that H-reflex modulation of both muscles may play a similar role in control of upright posture. PMID:22795783

  9. Modelling 3D control of upright stance using an optimal control strategy.

    PubMed

    Qu, Xingda; Nussbaum, Maury A

    2012-01-01

    A 3D balance control model of quiet upright stance is presented, based on an optimal control strategy, and evaluated in terms of its ability to simulate postural sway in both the anterior-posterior and medial-lateral directions. The human body was represented as a two-segment inverted pendulum. Several assumptions were made to linearise body dynamics, for example, that there was no transverse rotation during upright stance. The neural controller was presumed to be an optimal controller that generates ankle control torque and hip control torque according to certain performance criteria. An optimisation procedure was used to determine the values of unspecified model parameters including random disturbance gains and sensory delay times. This model was used to simulate postural sway behaviours characterised by centre-of-pressure (COP)-based measures. Confidence intervals for all normalised COP-based measures contained unity, indicating no significant differences between any of the simulated COP-based measures and corresponding experimental references. In addition, mean normalised errors for the traditional measures were < 8%, and those for most statistical mechanics measures were ∼3-66%. On the basis these results, the proposed 3D balance control model appears to have the ability to accurately simulate 3D postural sway behaviours. PMID:21598131

  10. Climate Literacy for Kids: Finding Medium, Message, and Stance

    NASA Astrophysics Data System (ADS)

    Fisher, D. K.; Leon, N.; Jackson, R.; Greene, M. P.

    2011-12-01

    As part of NASA's Global Climate Change (climate.nasa.gov) website (winner of the 2011Webby Award for Best Science Site), Climate Kids (climate.nasa.gov/kids) presents positive role models for green careers and encourages kids to be good climate citizens. But before they will care, they must understand. Climate Kids helps kids understand climate science by communicating at their own science awareness and maturity level, and by giving them concrete ways to start helping Earth now. Climate Kids, as informal education, speaks to upper-elementary-school-age kids in their own language and using some of their favorite media. In addition to simple, liberally illustrated text explanations of the basic science concepts, cartoons and games reinforce the concepts in a fun way. A growing section on green careers interviews enthusiastic individuals currently practicing their professions. In explaining what they do, these individuals reinforce the climate science concepts and "how to help" suggestions elsewhere on the site. The games also reinforce the green career choices. "Green Careers" currently features a "green" general contractor, a home energy auditor, a water-wise landscaper, a recycling program educator, and a renewable energy scientist. The message of the scientist, who designs wind energy farms and "architectural wind" arrays, is reinforced by the "Power-up" game. In this game, players move a wind turbine up or down to capture the wind and move a solar array back and forth to stay out of cloud shadows. Depending on how many "windows" of the game's "city" light up using these alternative energy sources, the player earns a bronze, silver, gold, or platinum "medal." A recycling game reinforces the messages of the recycling program educator about the importance of recycling in saving energy, what can and cannot be recycled, and how long trash items remain in a landfill before decomposing. In the game, a variety of throw-away objects rains down from the top of the screen. Various recycling bins (glass, plastic, metal, and paper) are lined up on the left and right sides of the screen, with a trash bin at the bottom. As an item drops, the player must quickly decide what kind of material it is made of and whether it is recyclable, then guide it into the appropriate bin. As the rate of items entering play increases, any missed items fall into the trash and stay there for a length of time proportional to their decomposition time. If the trash bin gets full, the game is over. While enjoying the increasing challenge of the game, players learn to identify many items as recyclable that they may not have recognized as recyclable before. Another feature on Climate Kids is "Climate Tales," a slightly edgy animated cartoon series (two episodes so far) about the adventures of a blundering polar bear, a chirpy tamarin monkey, and a grumpy old fish as "accidental tourists" around the planet, observing and dealing with the environmental conditions they encounter. Fairly complex concepts (such as reasons and implications of the declining abundance of phytoplankton) are woven into the tales. Climate Kids is a fun site for kids, educational and realistic, and yet positive and hopeful-the only reasonable stance to present to this young audience.

  11. Effect of foot deformity on conventional mechanical axis deviation and ground mechanical axis deviation during single leg stance and two leg stance in genu varum.

    PubMed

    Desai, Sameer Shrikrishna; Shetty, Gautam M; Song, Hae-Ryong; Lee, Seok Hyun; Kim, Tae Young; Hur, Chung Yong

    2007-12-01

    We assessed the effect of foot deformity on the loading axis of lower limbs in 33 patients with genu varum (25 bilateral and eigth unilateral) caused by varying etiologies including achondroplasia, cerebral palsy, prior trauma, rickets, metaphyseal chondrodysplasia and primary osteoarthritis using single leg stance and both leg stance radiographs. Deviation at the knee from the hip ankle line (conventional) and hip foot line (centre of hip to centre of heel) was calculated. A comparison was made between single leg stance and two leg stance for tibiocalcaneal angle, mechanical axis angle, knee and ankle joint line convergence angle, conventional mechanical axis deviation (MADC) and ground mechanical axis deviation (MADG). In addition comparisons were also made among three groups formed depending on the tibiocalcaneal angle and MADC-MADG difference for all the above measurements. Mechanical axis deviation (calculated using the two methods) varied with the talocalcaneal angle and single leg stance. Patients with a fixed subtalar varus and with severe genu varum, where the normal compensatory subtalar eversion could not compensate showed that conventional mechanical axis deviation was significantly higher by 3.4+/-2.4 mm and ground mechanical axis deviation degrees was significantly higher by 3.8+/-3.2 mm in single leg stance when compared to two leg stance (p<.0001). Foot deformity should be included during preoperative evaluation and planning for knee deformity correction. PMID:17825567

  12. Stance and swing phase costs in human walking

    PubMed Central

    Umberger, Brian R.

    2010-01-01

    Leg swing in human walking has historically been viewed as a passive motion with little metabolic cost. Recent estimates of leg swing costs are equivocal, covering a range from 10 to 33 per cent of the net cost of walking. There has also been a debate as to whether the periods of double-limb support during the stance phase dominate the cost of walking. Part of this uncertainty is because of our inability to measure metabolic energy consumption in individual muscles during locomotion. Therefore, the purpose of this study was to investigate the metabolic cost of walking using a modelling approach that allowed instantaneous energy consumption rates in individual muscles to be estimated over the full gait cycle. At a typical walking speed and stride rate, leg swing represented 29 per cent of the total muscular cost. During the stance phase, the double-limb and single-limb support periods accounted for 27 and 44 per cent of the total cost, respectively. Performing step-to-step transitions, which encompasses more than just the double-support periods, represented 37 per cent of the total cost of walking. Increasing stride rate at a constant speed led to greater double-limb support costs, lower swing phase costs and no change in single-limb support costs. Together, these results provide unique insight as to how metabolic energy is expended over the human gait cycle. PMID:20356877

  13. Using Metrics to Describe the Participative Stances of Members Within Discussion Forums

    PubMed Central

    Sharkey, Siobhan; Smithson, Janet; Ford, Tamsin; Emmens, Tobit; Hewis, Elaine; Sheaves, Bryony; Owens, Christabel

    2011-01-01

    Background Researchers using forums and online focus groups need to ensure they are safe and need tools to make best use of the data. We explored the use of metrics that would allow better forum management and more effective analysis of participant contributions. Objective To report retrospectively calculated metrics from self-harm discussion forums and to assess whether metrics add to other methods such as discourse analysis. We asked (1) which metrics are most useful to compare and manage forums, and (2) how metrics can be used to identify the participative stances of members to help manage discussion forums. Methods We studied the use of metrics in discussion forums on self-harm. SharpTalk comprised five discussion forums, all using the same software but with different forum compositions. SharpTalk forums were similar to most moderated forums but combined support and general social chat with online focus groups discussing issues on self-harm. Routinely recorded time-stamp data were used to derive metrics of episodes, time online, pages read, and postings. We compared metrics from the forums with views from discussion threads and from moderators. We identified patterns of participants’ online behavior by plotting scattergrams and identifying outliers and clusters within different metrics. Results In comparing forums, important metrics seem to be number of participants, number of active participants, total time of all participants logged on in each 24 hours, and total number of postings by all participants in 24 hours. In examining participative stances, the important metrics were individuals’ time logged per 24 hours, number of episodes, mean length of episodes, number of postings per 24 hours, and location within the forum of those postings. Metric scattergrams identified several participative stances: (1) the “caretaker,” who was “always around,” logged on for a much greater time than most other participants, posting but mainly in response to others and rarely initiating threads, (2) the “butterfly,” who “flitted in and out,” had a large number of short episodes, (3) two “discussants,” who initiated many more discussion threads than anybody else and posted proportionately less in the support room, (4) “here for you,” who posted frequently in the support room in response to other participants’ threads, and (5) seven “people in distress,” who posted many comments in the support room in comparison with their total postings and tended to post on their own threads. Conclusions Real-time metrics may be useful: (1) by offering additional ways of comparing different discussion forums helping with their management, and (2) by identifying participative stances of individuals so allowing better moderation and support of forums, and more effective use of the data collected. For this to happen, researchers need to publish metrics for their discussion forums and software developers need to offer more real-time metrics facilities. PMID:21239373

  14. Risk Taking in Late Adolescence: Relations between Sociomoral Reasoning, Risk Stance, and Behavior

    ERIC Educational Resources Information Center

    Shaw, Leigh A.; Amsel, Eric; Schillo, Joshua

    2011-01-01

    This study explored relations among late adolescents' sociomoral reasoning about risk taking, risk stance, and behavior. One-hundred and thirty-two participants (18-20-year-olds) were surveyed about their own risk stance (Avoidant, Opportunistic, Curious, Risk Seeking) and behavior in three realms (Alcohol Use, Drug Use, Reckless Driving), and…

  15. Linguistic Markers of Stance in Early and Advanced Academic Writing: A Corpus-Based Comparison

    ERIC Educational Resources Information Center

    Aull, Laura L.; Lancaster, Zak

    2014-01-01

    This article uses corpus methods to examine linguistic expressions of stance in over 4,000 argumentative essays written by incoming first-year university students in comparison with the writing of upper-level undergraduate students and published academics. The findings reveal linguistic stance markers shared across the first-year essays despite…

  16. A Cross-Cultural Analysis of Stance in Disaster News Reports

    ERIC Educational Resources Information Center

    Liu, Lian; Stevenson, Marie

    2013-01-01

    This study examines stance in cross-cultural media discourse by comparing disaster news reports on the Sichuan earthquake of May 2008 in a Chinese, an Australian Chinese, and an Australian newspaper. The stance taken in the news reports is examined using the Attitude sub-system of Martin and White's (2005) Appraisal framework. The analysis…

  17. Embracing the Inherent Tensions in Teaching Mathematics from an Equity Stance

    ERIC Educational Resources Information Center

    Gutierrez, Rochelle

    2009-01-01

    Rather than delineating a list of practices that are important for ensuring that mathematics prepares students for a more democratic citizenship, the author has outlined in this article three tensions in teaching that she argues are important in developing an equity stance in mathematics education. This focus on a "stance" suggests that the kinds…

  18. Ninth Grade Students' Negotiation of Aesthetic, Efferent, and Critical Stances in Response to a Novel Set in Afghanistan

    ERIC Educational Resources Information Center

    Taliaferro, Cheryl

    2011-01-01

    This qualitative, action research study was guided by two primary research questions. First, how do students negotiate aesthetic, efferent, and critical stances when reading a novel set in Afghanistan? Second, how do aesthetic and efferent stances contribute to or hinder the adoption of a critical stance? A large body of research exists that…

  19. Modulation of tibialis anterior muscle activity changes with upright stance width.

    PubMed

    Lemos, Thiago; Imbiriba, Luís A; Vargas, Claudia D; Vieira, Taian M

    2015-02-01

    When individuals stand with their feet apart, activation of tibialis anterior (TA) muscle seems to slightly exceed rest levels. In narrow stances, conversely, the stabilization of body lateral sways may impose marked, active demand on ankle inversors/eversors. In this study we investigate how much the modulation in TA activity, associated to center of pressure (COP) lateral sways, changes when stance width reduces. Surface EMG and COP coordinates were collected from 17 subjects at three different stances: feet apart, feet together and tandem. Pearson correlation analysis was applied to check whether the expected greater modulations in TA activity corresponded to a stronger association between fluctuations in EMG amplitude and COP lateral sways. When standing at progressively narrower stances participants showed larger fluctuations in COP lateral sways (p<0.01) and higher EMG-COP association (p<0.01); marked increases in TA activity were only observed in tandem stance (p<0.001). Interestingly, more pronounced modulations in TA activity were observed for subjects showing greater association between EMG amplitude and COP sways in feet together and tandem stance (Pearson R>0.56, p<0.02), though not when standing with feet apart (R=-0.22, p=0.40). These results indicate that the contribution of TA activity to lateral sway control increases for narrower stances. PMID:25156446

  20. Calcaneal Plantar Flexion During the Stance Phase of Gait.

    PubMed

    Stamm, Stacy E; Chiu, Loren Z

    2016-04-01

    When the rear- and forefoot are constrained, calcaneal plantar flexion may occur, deforming the longitudinal arch. Previous research has reported calcaneal motion relative to the tibia or forefoot; these joint rotations may not accurately describe rotation of the calcaneus alone. This investigation: (1) characterized the calcaneus and leg segment and ankle joint rotations during stance in gait, and (2) described the range of calcaneal plantar flexion in different structural arch types. Men (n = 14) and women (n = 16) performed gait in a motion analysis laboratory. From heel strike to heel off, the leg rotated forward while the calcaneus plantar flexed. Before foot flat, calcaneal plantar flexion was greater than forward leg rotation, resulting in ankle plantar flexion. After foot flat, forward leg rotation was greater than calcaneal plantar flexion, resulting in ankle dorsiflexion. Structural arch type was classified using the longitudinal arch angle. The range of calcaneal plantar flexion from foot flat to heel off was small in low (-2° to -8°), moderate in high (-3° to -12°), and large in normal (-2° to -20°) structural arches. Calcaneal plantar flexion in gait during midstance may reflect functional arch characteristics, which vary depending on structural arch type. PMID:26398966

  1. Stance Postural Strategies in Patients with Chronic Inflammatory Demyelinating Polyradiculoneuropathy

    PubMed Central

    Missori, Paolo; Trompetto, Carlo; Fattapposta, Francesco

    2016-01-01

    Introduction Polyneuropathy leads to postural instability and an increased risk of falling. We investigated how impaired motor impairment and proprioceptive input due to neuropathy influences postural strategies. Methods Platformless bisegmental posturography data were recorded in healthy subjects and patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Each subject stood on the floor, wore a head and a hip electromagnetic tracker. Sway amplitude and velocity were recorded and the mean direction difference (MDD) in the velocity vector between trackers was calculated as a flexibility index. Results Head and hip postural sway increased more in patients with CIDP than in healthy controls. MDD values reflecting hip strategies also increased more in patients than in controls. In the eyes closed condition MDD values in healthy subjects decreased but in patients remained unchanged. Discussion Sensori-motor impairment changes the balance between postural strategies that patients adopt to maintain upright quiet stance. Motor impairment leads to hip postural strategy overweight (eyes open), and prevents strategy re-balancing when the sensory context predominantly relies on proprioceptive input (eyes closed). PMID:26977594

  2. Stance limb kinetics of older male athletes endurance running performance.

    PubMed

    Diss, Ceri; Gittoes, Marianne J; Tong, Richard; Kerwin, David G

    2015-09-01

    The aim of this study was to examine the age-based, lower limb kinetics of running performances of endurance athletes. Six running trials were performed by 24 male athletes, who were distinguished by three age groupings (S35: 26-32 years, M50: 50-54 years, M60+: 60-68 years). Lower limb coordinate and ground reaction force data were collected using a nine camera infra-red system synchronised with a force plate. A slower anteroposterior (M ± SD S35 = 4.13 ± 0.54 m/s: M60+ = 3.34 ± 0.40 m/s, p < 0.05) running velocity was associated with significant (p < 0.05) decreases in step length and discrete vertical ground contact force between M60+and S35 athletes. The M60+athletes simultaneously generated a 32% and 42% reduction (p < 0.05) in ankle joint moment when compared to the M50 and S35 athletes and 72% (p < 0.05) reduction in knee joint stiffness when compared to S35 athletes. Age-based declines in running performance were associated with reduced stance phase force tolerance and generation that may be accounted for due to an inhibited force-velocity muscular function of the lower limb. Joint-specific coaching strategies customised to athlete age are warranted to maintain/enhance athletes' dynamic performance. PMID:26208084

  3. Tibial torque generation in a flexed weight-bearing stance.

    PubMed

    Shoemaker, S C; Markolf, K L; Dorey, F J; Zager, S; Namba, R

    1988-03-01

    Internal and external torque generated about the long axis of the lower extremity was measured in 18 male subjects who were instructed to twist with maximal effort against a fixed footplate containing an instrumented torque cell. Mean torque values ranged from 30 to 71 newton meters (Nm) depending upon the test conditions. Torques recorded during the flexed single-leg stance were 19% to 49% higher than those measured while seated. Values at 45 degrees of knee flexion were 11% to 16% greater than those at 20 degrees. Torques generated while wearing a ski boot were 8% to 11% greater than those recorded in an athletic shoe. When movement of the pelvis and upper torso was allowed, torque values were 17% to 49% higher than those recorded when the hips and shoulders were restrained which allowed only lower leg musculature to act in an isolated fashion. There were no differences between internal versus external generated torques when the hips and torso were restrained. When the hips and shoulders were unrestrained, internal torque was 12% greater than external torque. There were no strong correlations between generated torque and body weight or height. These generated torque values suggest that if ski bindings are set to American Society for Testing and Materials (ASTM) standards for twist-release torque, then upper torso and pelvic movement in conjunction with tensed knee musculature (i.e., a "locked knee") may be necessary to accomplish binding release. Use of the lower leg musculature alone (i.e., ankle twist) may not generate sufficient torque for release. PMID:3342561

  4. A quasi-passive compliant stance control Knee-Ankle-Foot Orthosis.

    PubMed

    Shamaei, Kamran; Napolitano, Paul C; Dollar, Aaron M

    2013-06-01

    In this paper, we present the design of a novel quasi-passive stance-control orthosis that implements a natural amount of knee compliance during the weight acceptance phase and potentially the entire stance phase of the gait, and allows for free motion during the rest of the gait. We explain that the unaffected knee behaves close to a linear torsional spring in stance and hypothesize that an assistive device that places a linear spring of appropriate stiffness in parallel with the knee can help restore the natural behavior of the joint in stance. We present the design of a friction-based latching mechanism and a control algorithm that engages the spring in parallel with the knee in stance and disengages it during the swing phase of gait, and explain how this module is implemented into a brace in order to create a novel class of compliant stance control orthosis. The device is quasi-passive in that a small actuator serves to lock and unlock the spring module, but the device otherwise requires no actuation and very little power, computation, and control to operate. PMID:24187288

  5. Organization position statements and the stance of "studied neutrality" on euthanasia in palliative care.

    PubMed

    Johnstone, Megan-Jane

    2012-12-01

    In recent years, palliative care and related organizations have increasingly adopted a stance of "studied neutrality" on the question of whether euthanasia should be legalized as a bona fide medical regimen in palliative care contexts. This stance, however, has attracted criticism from both opponents and proponents of euthanasia. Pro-euthanasia activists see the stance as an official position of indecision that is fundamentally disrespectful of a patient's right to "choose death" when life has become unbearable. Some palliative care constituents, in turn, are opposed to the stance, contending that it reflects an attitude of "going soft" on euthanasia and as weakening the political resistance that has hitherto been successful in preventing euthanasia from becoming more widely legalized. In this article, attention is given to examining critically the notion and possible unintended consequences of adopting a stance of studied neutrality on euthanasia in palliative care. It is argued that although palliative care and related organizations have an obvious stake in the outcome of the euthanasia debate, it is neither unreasonable nor inconsistent for such organizations to be unwilling to take a definitive stance on the issue. It is further contended that, given the long-standing tenets of palliative care, palliative care organizations have both a right and a responsibility to defend the integrity of the principles and practice of palliative care and to resist demands for euthanasia to be positioned either as an integral part or logical extension of palliative care. PMID:22771130

  6. The default mode of human brain function primes the intentional stance.

    PubMed

    Spunt, Robert P; Meyer, Meghan L; Lieberman, Matthew D

    2015-06-01

    Humans readily adopt an intentional stance to other people, comprehending their behavior as guided by unobservable mental states such as belief, desire, and intention. We used fMRI in healthy adults to test the hypothesis that this stance is primed by the default mode of human brain function present when the mind is at rest. We report three findings that support this hypothesis. First, brain regions activated by actively adopting an intentional rather than nonintentional stance to a social stimulus were anatomically similar to those demonstrating default responses to fixation baseline in the same task. Second, moment-to-moment variation in default activity during fixation in the dorsomedial PFC was related to the ease with which participants applied an intentional--but not nonintentional--stance to a social stimulus presented moments later. Finally, individuals who showed stronger dorsomedial PFC activity at baseline in a separate task were generally more efficient when adopting the intentional stance and reported having greater social skills. These results identify a biological basis for the human tendency to adopt the intentional stance. More broadly, they suggest that the brain's default mode of function may have evolved, in part, as a response to life in a social world. PMID:25603027

  7. Development of a mechatronic platform and validation of methods for estimating ankle stiffness during the stance phase of walking.

    PubMed

    Rouse, Elliott J; Hargrove, Levi J; Perreault, Eric J; Peshkin, Michael A; Kuiken, Todd A

    2013-08-01

    The mechanical properties of human joints (i.e., impedance) are constantly modulated to precisely govern human interaction with the environment. The estimation of these properties requires the displacement of the joint from its intended motion and a subsequent analysis to determine the relationship between the imposed perturbation and the resultant joint torque. There has been much investigation into the estimation of upper-extremity joint impedance during dynamic activities, yet the estimation of ankle impedance during walking has remained a challenge. This estimation is important for understanding how the mechanical properties of the human ankle are modulated during locomotion, and how those properties can be replicated in artificial prostheses designed to restore natural movement control. Here, we introduce a mechatronic platform designed to address the challenge of estimating the stiffness component of ankle impedance during walking, where stiffness denotes the static component of impedance. The system consists of a single degree of freedom mechatronic platform that is capable of perturbing the ankle during the stance phase of walking and measuring the response torque. Additionally, we estimate the platform's intrinsic inertial impedance using parallel linear filters and present a set of methods for estimating the impedance of the ankle from walking data. The methods were validated by comparing the experimentally determined estimates for the stiffness of a prosthetic foot to those measured from an independent testing machine. The parallel filters accurately estimated the mechatronic platform's inertial impedance, accounting for 96% of the variance, when averaged across channels and trials. Furthermore, our measurement system was found to yield reliable estimates of stiffness, which had an average error of only 5.4% (standard deviation: 0.7%) when measured at three time points within the stance phase of locomotion, and compared to the independently determined stiffness values of the prosthetic foot. The mechatronic system and methods proposed in this study are capable of accurately estimating ankle stiffness during the foot-flat region of stance phase. Future work will focus on the implementation of this validated system in estimating human ankle impedance during the stance phase of walking. PMID:23719922

  8. Prediction of walking speed using single stance force or pressure measurements in healthy subjects.

    PubMed

    Keijsers, N L W; Stolwijk, N M; Renzenbrink, G J; Duysens, J

    2016-01-01

    Walking speed is one of the best measures of overall walking capacity. In plantar pressure measurements, walking speed can be assessed using contact time, but it is only moderately correlated with walking speed. The center of pressure might be of more value to indicate walking speed since walking speed alters foot loading. Therefore, the purpose of this study is to assess walking speed using the velocity of the center of pressure (VCOP). Thirty-three subjects walked over a Footscan pressure plate at three speed conditions; slow, preferred, and fast. Walking speed was measured by a motion analysis system. (Multiple) linear regression analysis was used to indicate the relation between walking speed and independent variables derived from the pressure plate such as mean VCOP and stance time for all walking conditions separately and together. The mean VCOP had the highest correlation coefficient value with walking speed for all walking conditions combined (0.94) and for the preferred walking condition (0.80). The multiple regression analysis, based on a number of additional parameters, revealed a small to modest increase in the performance of predicting walking speed (r=0.98 for combined and r=0.93 for preferred). The mean VCOP was the best predictor for walking speed when using a plantar pressure plate. The mean VCOP predicts the walking speed with a 95% accuracy of 0.20m/s when healthy subjects walk at their preferred walking speed. PMID:26669958

  9. Single stance stability and proprioceptive control in older adults living at home: gender and age differences.

    PubMed

    Riva, Dario; Mamo, Carlo; Fanì, Mara; Saccavino, Patrizia; Rocca, Flavio; Momenté, Manuel; Fratta, Marianna

    2013-01-01

    In developed countries, falls in older people represent a rising problem. As effective prevention should start before the risk becomes evident, an early predictor is needed. Single stance instability would appear as a major risk factor. Aims of the study were to describe single stance stability, its sensory components, and their correlation with age and gender. A random sample of 597 older adults (319 men, 278 women) living at home, aged 65-84, was studied. Stability tests were performed with an electronic postural station. The single stance test showed the impairment of single stance stability in older individuals (75-84 yrs). The significant decline of stability in the older subjects may be explained by the impairment of proprioceptive control together with the decrease in compensatory visual stabilization and emergency responses. Younger subjects (65-74 yrs) exhibited better, but still inadequate, proprioceptive control with compensatory visual stabilization. Gender differences appeared in older subjects: women were significantly less stable than men. The measurement of the sensory components of single stance stability could aid in the early detection of a decay in antigravity movements many years before the risk of falling becomes evident. Adequate proprioceptive control could mitigate the effects of all other risks of falling. PMID:23984068

  10. Double-leg stance and dynamic balance in individuals with functional ankle instability.

    PubMed

    Groters, S; Groen, B E; van Cingel, R; Duysens, J

    2013-09-01

    To investigate whether double-leg stance could reveal balance deficits in subjects with functional ankle instability (FAI) and whether such an assessment of static balance would be correlated with measures of dynamic instability, 16 individuals with FAI and 16 healthy controls participated in this study. Static postural control was tested using double-leg stance (either with the eyes open (EO) or closed (EC)) on a dual-plate force platform. Dynamic balance was evaluated using the Multiple Hop Test (MHT) and a weight-shifting task. FAI subjects were significantly less stable in the anteroposterior direction during double-leg stance (as assessed by velocity of centre of pressure, VCP), both for the EO and EC condition. In the mediolateral direction the VCP values were also higher in FAI, but significance was only found for the EC condition (p=.02). FAI subjects made significantly more balance errors compared to healthy controls (p<.001) on both the affected and less affected leg during MHT. There were no significant differences between FAI and healthy subjects during the weight-shifting task. No relationship was found between double-leg stance and MHT measures (all correlations (rs) less than .30). This study suggests that static postural control during double-leg stance is impaired in FAI subjects. Although dynamic balance during MHT is also affected, no significant relationship was found between static and dynamic measurements, which indicate that they are most probably related to different aspects of postural control. PMID:23810093

  11. Single Stance Stability and Proprioceptive Control in Older Adults Living at Home: Gender and Age Differences

    PubMed Central

    Riva, Dario; Mamo, Carlo; Fanì, Mara; Saccavino, Patrizia; Rocca, Flavio; Momenté, Manuel; Fratta, Marianna

    2013-01-01

    In developed countries, falls in older people represent a rising problem. As effective prevention should start before the risk becomes evident, an early predictor is needed. Single stance instability would appear as a major risk factor. Aims of the study were to describe single stance stability, its sensory components, and their correlation with age and gender. A random sample of 597 older adults (319 men, 278 women) living at home, aged 65–84, was studied. Stability tests were performed with an electronic postural station. The single stance test showed the impairment of single stance stability in older individuals (75–84 yrs). The significant decline of stability in the older subjects may be explained by the impairment of proprioceptive control together with the decrease in compensatory visual stabilization and emergency responses. Younger subjects (65–74 yrs) exhibited better, but still inadequate, proprioceptive control with compensatory visual stabilization. Gender differences appeared in older subjects: women were significantly less stable than men. The measurement of the sensory components of single stance stability could aid in the early detection of a decay in antigravity movements many years before the risk of falling becomes evident. Adequate proprioceptive control could mitigate the effects of all other risks of falling. PMID:23984068

  12. Motor strategies used by rats spinalized at birth to maintain stance in response to imposed perturbations

    PubMed Central

    Giszter, Simon F; Davies, Michelle R; Graziani, Virginia

    2010-01-01

    Some rats spinalized P1/P2 achieve autonomous weight supported locomotion and quiet stance as adults. We used force platforms and robot applied perturbations to test such spinalized rats (n=6) which exhibited both weight supporting locomotion and stance, and also normal rats (n=8). Ground reaction forces in individual limbs, and the animals center of pressure were examined. In normal rats, both forelimbs and hindlimbs participated actively to control horizontal components of ground reaction forces. Rostral perturbations increased forelimb ground reaction forces, and caudal perturbations increased hindlimb ground reaction forces. Operate rats carried 60% body weight on the forelimbs and had a more rostral center of pressure placement. Normal rats pattern was to carry significantly more weight on the hindlimbs in quiet stance (~60%). Operate rats strategy of compensation for perturbations was entirely in forelimbs; as a result, the hind-limbs were largely isolated from the perturbation. Stiffness magnitude of the whole body was measured: its magnitude was hourglass shaped, with the principal axis oriented rostrocaudally. Operate rats were significantly less stiff; only 60-75% of normal rats stiffness. The injured rats adopt a stance strategy that isolates the hindlimbs from perturbation and may thus prevent hindlimb loadings. Such loadings could initiate reflex stepping, which we observed. This might activate lumbar pattern generators used in their locomotion. Adult spinalized rats never achieve independent hindlimb weight supported stance. The stance strategy of the P1 spinalized rats differed strongly from the behavior of intact rats and may be difficult for rats spinalized as adults to master. PMID:17287444

  13. Constructing Language Normativity through the Animation of Stance in Spanish Language Medical Consultations

    PubMed Central

    Vickers, Caroline H.; Deckert, Sharon K.; Goble, Ryan

    2013-01-01

    The purpose of this study is to examine the construction of language normativity as medical providers interact with patients and animate stance within Spanish language medical consultations. The context of the study is a clinic in which providers use Spanish to communicate with monolingual Spanish-speaking patients. This clinic is in the United States, an English-speaking macro-societal context. Findings indicate that providers who are second language users of Spanish animate stance and interact with patients in ways that English is constructed as normative and Spanish as marked. Implications include the need to consider how the construction of language normativity within medical consultations affects health outcomes. PMID:24156518

  14. Fatigue-Induced Balance Impairment in Young Soccer Players

    PubMed Central

    Pau, Massimiliano; Ibba, Gianfranco; Attene, Giuseppe

    2014-01-01

    Context: Although balance is generally recognized to be an important feature in ensuring good performance in soccer, its link with functional performance remains mostly unexplored, especially in young athletes. Objective: To investigate changes in balance induced by fatigue for unipedal and bipedal static stances in young soccer players. Design: Crossover study. Setting: Biomechanics laboratory and outdoor soccer field. Patients or Other Participants: Twenty-one male soccer players (age = 14.5 ± 0.2 years, height = 164.5 ± 5.6 cm, mass = 56.8 ± 6.8 kg). Intervention(s): Static balance was assessed with postural-sway analysis in unipedal and bipedal upright stance before and after a fatigue protocol consisting of a repeated sprint ability (RSA) test (2 × 15-m shuttle sprint interspersed with 20 seconds of passive recovery, repeated 6 times). Main Outcome Measure(s): On the basis of the center-of-pressure (COP) time series acquired during the experimental tests, we measured sway area, COP path length, and COP maximum displacement and velocity in the anteroposterior and mediolateral directions. Results: Fatigue increased all sway values in bipedal stance and all values except COP velocity in the mediolateral direction in unipedal stance. Fatigue index (calculated on the basis of RSA performance) was positively correlated with fatigue/rest sway ratio for COP path length and COP velocity in the anteroposterior and mediolateral directions for nondominant single-legged stance. Conclusions: Fatigued players exhibited reduced performance of the postural-control system. Participants with better performance in the RSA test appeared less affected by balance impairment, especially in single-legged stance. PMID:24568227

  15. Movement strategies and sensory reweighting in tandem stance: differences between trained tightrope walkers and untrained subjects.

    PubMed

    Honegger, F; Tielkens, R J M; Allum, J H J

    2013-12-19

    Does skill with a difficult task, such as tightrope walking, lead to improved balance through altered movement strategies or through altered weighting of sensory inputs? We approached this question by comparing tandem stance (TS) data between seven tightrope walkers and 12 untrained control subjects collected under different sensory conditions. All subjects performed four TS tasks with eyes open or closed, on a normal firm or foam surface (EON, ECN, EOF, ECF); tightrope walkers were also tested on a tightrope (EOR). Head, upper trunk and pelvis angular velocities were measured with gyroscopes in pitch and roll. Power spectral densities (PSDs) ratios, and transfer function gains (TFG) between these body segments were calculated. Center of mass (CoM) excursions and its virtual time to contact a virtual base of support boundary (VTVBS) were also estimated. Gain nonlinearities, in the form of decreased trunk to head and trunk to pelvis PSD ratios and TFGs, were present with increasing sensory task difficulty for both groups. PSD ratios and TFGs were less in trained subjects, though, in absolute terms, trained subjects moved their head, trunk, pelvis and CoM faster than controls, and had decreased VTVBS. Head roll amplitudes were unchanged with task or training, except above 3Hz. CoM amplitude deviations were not less for trained subjects. For the trained subjects, EOR measures were similar to those of ECF. Training standing on a tightrope induces a velocity modification of the same TS movement strategy used by untrained controls. More time is spent exploring the limits of the base of support with an increased use of fast trunk movements to control balance. Our evidence indicates an increased reliance on neck and pelvis proprioceptive inputs. The similarity of TS on foam to that on the tightrope suggests that the foam tasks are useful for effective training of tightrope walking. PMID:24090964

  16. Controlling Posture and Vergence Eye Movements in Quiet Stance: Effects of Thin Plantar Inserts

    PubMed Central

    Foisy, A.; Gaertner, C.; Matheron, E.; Kapoula, Z.

    2015-01-01

    The purpose of this study was to assess properties of vergence and saccade eye movements as well as posture in quiet stance, and the effects of thin plantar inserts upon postural and oculomotor control. The performances of 36 young healthy subjects were recorded by a force platform and an eye tracker in three testing conditions: without plantar stimulation, with a 3 millimetre-thick plantar insert, either a Medial or a Lateral Arch Support (MAS / LAS). The results showed a decrease of the Surface and Variance of Speed and a more posterior position of the CoP with either stimulation compared with the control condition. The fractal analysis showed a decrease with MAS. Wavelet analysis in the time-frequency domain revealed an increase in the Cancelling Time of the low frequency band with MAS. These results suggest a better stability for a lower energy cost. Concerning eye movements, the inserts influenced only vergence (not saccades): MAS caused an increase of the phasic amplitude of divergence, and conversely a decrease of the tonic amplitude. In contrast, LAS caused an increase of the tonic amplitude of convergence. Thus, MAS renders divergence less visually driven, while LAS renders convergence more visually driven. We conclude that the CNS uses the podal signal for both postural and vergence control via specific mechanisms. Plantar inserts have an influence upon posture and vergence movements in a different way according to the part of the foot sole being stimulated. These results can be useful to clinicians interested in foot or eye. PMID:26637132

  17. EFL Doctoral Students' Conceptions of Authorial Stance in Academic Knowledge Claims and the Tie to Epistemic Beliefs

    ERIC Educational Resources Information Center

    Chang, Peichin; Tsai, Chin-Chung

    2014-01-01

    Taking an effective authorial stance in research argumentation has been designated as both vitally important and challenging. The study investigated English as a foreign language (EFL) doctoral students' conceptions of authorial stance, the role of domains in affecting their conceptions, and the ties of the conceptions to the…

  18. Divergent Effects of Cognitive Load on Quiet Stance and Task-Linked Postural Coordination

    ERIC Educational Resources Information Center

    Mitra, Suvobrata; Knight, Alec; Munn, Alexandra

    2013-01-01

    Performing a cognitive task while maintaining upright stance can lead to increased or reduced body sway depending on tasks and experimental conditions. Because greater sway is commonly taken to indicate loosened postural control, and vice versa, the precise impact of cognitive load on postural stability has remained unclear. In much of the large…

  19. Reported Thought as a Stance-Taking Device in Korean Conversation

    ERIC Educational Resources Information Center

    Kim, Mary Shin

    2014-01-01

    Analyses of 34 cases of direct reported thought found in ordinary Korean conversations illustrate a routine practice in the use of reported thought-reenacting a prior thought to demonstrate how the speaker's current stance originated. Often, such thoughts are not simply momentary, isolated thoughts in passing but are consequential thoughts

  20. Reported Thought as a Stance-Taking Device in Korean Conversation

    ERIC Educational Resources Information Center

    Kim, Mary Shin

    2014-01-01

    Analyses of 34 cases of direct reported thought found in ordinary Korean conversations illustrate a routine practice in the use of reported thought-reenacting a prior thought to demonstrate how the speaker's current stance originated. Often, such thoughts are not simply momentary, isolated thoughts in passing but are consequential thoughts…

  1. Stance and Engagement in Pure Mathematics Research Articles: Linking Discourse Features to Disciplinary Practices

    ERIC Educational Resources Information Center

    McGrath, Lisa; Kuteeva, Maria

    2012-01-01

    Recent ESP research into academic writing has shown how writers convey their stance and interact with readers across different disciplines. However, little research has been carried out into the disciplinary writing practices of the pure mathematics academic community from an ESP genre analysis perspective. This study begins to address this gap by…

  2. Pedagogical Stances of High School ESL Teachers: "Huelgas" in High School ESL Classrooms

    ERIC Educational Resources Information Center

    del Carmen Salazar, Maria

    2010-01-01

    This article presents a qualitative case study of the pedagogical stances of high school English as a Second Language (ESL) teachers, and the subsequent responses of resistance or conformity by their English Language Learners (ELLs). The participants include three high school ESL teachers and 60 high school ESL students of Mexican origin. Findings…

  3. Changing and Changed Stance toward Norm Selection in Philippine Universities: Its Pedagogical Implications

    ERIC Educational Resources Information Center

    Bernardo, Alejandro S.

    2014-01-01

    This paper reports the results of a survey which involved College English teachers from three leading universities in the Philippines. The results point to one conclusion--College English teachers now have a changing and changed stance toward norm selection in Philippine Universities. The results give the impression that a good number of College…

  4. Stylizing Voices, Stances, and Identities Related to Medium of Education in India

    ERIC Educational Resources Information Center

    Sandhu, Priti

    2015-01-01

    This study analyzes the narrative-based interview data of three Indian women to examine the manner in which they utilize stylization to construct identity-rich, ideological stances related to discriminatory discourses of Hindi and English medium education in the linguistically rich, albeit complex, present-day context of India. Stylization is

  5. Stance control knee mechanism for lower-limb support in hybrid neuroprosthesis

    PubMed Central

    To, Curtis S.; Kobetic, Rudi; Bulea, Thomas C.; Audu, Musa L.; Schnellenberger, John R.; Pinault, Gilles; Triolo, Ronald J.

    2014-01-01

    A hydraulic stance control knee mechanism (SCKM) was developed to fully support the knee against flexion during stance and allow uninhibited motion during swing for individuals with paraplegia using functional neuromuscular stimulation (FNS) for gait assistance. The SCKM was optimized for maximum locking torque for body-weight support and minimum resistance when allowing for free knee motion. Ipsilateral and contralateral position and force feedback were used to control the SCKM. Through bench and nondisabled testing, the SCKM was shown to be capable of supporting up to 70 N-m, require no more than 13% of the torque achievable with FNS to facilitate free motion, and responsively and repeatedly unlock under an applied flexion knee torque of up to 49 N-m. Preliminary tests of the SCKM with an individual with paraplegia demonstrated that it could support the body and maintain knee extension during stance without the stimulation of the knee extensor muscles. This was achieved without adversely affecting gait, and knee stability was comparable to gait assisted by knee extensor stimulation during stance. PMID:21938668

  6. Turkish Language Teachers' Stance Taking Movements in the Discourse on Globalization and Language

    ERIC Educational Resources Information Center

    Coskun, Ibrahim

    2013-01-01

    This study investigates how Turkish teachers take and give stances in the discourse on globalization and language by using linguistic resources. According to the findings obtained through the discourse analysis of the corpus that consisted of 36 h of recording of the discussion among 4 teachers with 5 to 10 years of teaching experience, the…

  7. From Tununak to Beaufort: Taking a Critical Inquiry Stance as a First Year Teacher

    ERIC Educational Resources Information Center

    Fecho, Bob; Price, Kim; Read, Chris

    2004-01-01

    In this article, the authors show how two first year teachers a continent apart--Kim in the village of Tununak on the Bering Sea in Alaska and Chris in Beaufort, South Carolina, on the Atlantic Ocean--were able to take inquiry stances on their classrooms. In particular, through analysis of e-mails written in Chris' and Kim's first years of…

  8. Communicating Epistemic Stance: How Speech and Gesture Patterns Reflect Epistemicity and Evidentiality

    ERIC Educational Resources Information Center

    Roseano, Paolo; González, Montserrat; Borràs-Comes, Joan; Prieto, Pilar

    2016-01-01

    This study investigates how epistemic stance is encoded and perceived in face-to-face communication when language is regarded as comprised by speech and gesture. Two studies were conducted with this goal in mind. The first study consisted of a production task in which participants performed opinion reports. Results showed that speakers communicate…

  9. In-vivo Tibiofemoral Cartilage Deformation during the Stance Phase of Gait

    PubMed Central

    Liu, Fang; Kozanek, Michal; Hosseini, Ali; Van de Velde, Samuel K.; Gill, Thomas J.; Rubash, Harry E.; Li, Guoan

    2009-01-01

    The knowledge of articular cartilage contact biomechanics in the knee joint is important for understanding the joint function and cartilage pathology. However, the in-vivo tibiofemoral articular cartilage contact biomechanics during gait remains unknown. The objective of this study was to determine the in vivo tibiofemoral cartilage contact biomechanics during the stance phase of treadmill gait. Eight healthy knees were magnetic resonance (MR) scanned and imaged with a dual fluoroscopic system during gait on a treadmill. The tibia, femur and associated cartilage were constructed from the MR images and combined with the dual fluoroscopic images to determine in vivo cartilage contact deformation during the stance phase of gait. Throughout the stance phase of gait, the magnitude of peak compartmental contact deformation ranged between 7% and 23% of the resting cartilage thickness and occurred at regions with thicker cartilage. Its excursions in the anteroposterior direction were greater in the medial tibiofemoral compartment as compared to those in the lateral compartment. The contact areas throughout the stance phase were greater in the medial compartment than in the lateral compartment. The information on in vivo tibiofemoral cartilage contact biomechanics during gait could be used to provide physiological boundaries for in vitro testing of cartilage. Also, the data on location and magnitude of deformation among non-diseased knees during gait could identify where loading and later injury might occur in diseased knees. PMID:19896131

  10. Elementary Students' Roles and Epistemic Stances during Document-Based History Lessons

    ERIC Educational Resources Information Center

    Nokes, Jeffery D.

    2014-01-01

    This article reports on a study that repositioned elementary students in new roles as active, critical participants in historical inquiry--roles that required a more mature epistemic stance. It reports 5th-grade students' responses to instructional methods intended to help them understand the nature of historical knowledge, appreciate the…

  11. Effect of a Wide Stance on Block Start Performance in Sprint Running

    PubMed Central

    Otsuka, Mitsuo; Kurihara, Toshiyuki; Isaka, Tadao

    2015-01-01

    This study aimed to clarify the effect of widened stance width at the set position during the block start phase in sprint running on kinematics and kinetics at the hip joint and block-induced power. Fourteen male sprinters volunteered to participate in this study. They performed three block-start trials with a normal stance width (25 ± 1 cm, normal condition) and a widened stance width (45 ± 2 cm, widened condition) at the set position. The block start movements were recorded at 250 Hz with high-speed cameras and the ground reaction forces at 1250 Hz with force plates. During the block phase in the widened condition, the hip abduction and external rotation angles in both legs were significantly larger and smaller, respectively, than those in the normal condition. The positive peak value of the hip power in the rear leg was significantly greater in the widened condition than that in the normal condition. However, no significant difference was seen in the normalized block-induced power between the widened and normal conditions. We conclude that a widened stance width at the set position affects the hip-joint kinematics and rear hip power generation during the block start phase, but no effect on the block-induced power when considering sprinting performance during the whole block start phase. PMID:26544719

  12. Temporal Resolution Requirements For The Double Stance Period Of Human Gait

    NASA Astrophysics Data System (ADS)

    Baumann, Juerg U.; Procter, Philip; Schaer, Alex

    1983-07-01

    Study of transient force phenomena in the double stance period of normal gait suggests that high temporal resolution is required in concommittant movement analysis. The present study concludes that at least 300 pictures per second are necessary to resolve kinematic transients associated with heel strike.

  13. Changing and Changed Stance toward Norm Selection in Philippine Universities: Its Pedagogical Implications

    ERIC Educational Resources Information Center

    Bernardo, Alejandro S.

    2014-01-01

    This paper reports the results of a survey which involved College English teachers from three leading universities in the Philippines. The results point to one conclusion--College English teachers now have a changing and changed stance toward norm selection in Philippine Universities. The results give the impression that a good number of College

  14. Inquiry as Stance: Practitioner Research for the Next Generation. Practitioners Inquiry

    ERIC Educational Resources Information Center

    Cochran-Smith, Marilyn; Lytle, Susan L.

    2009-01-01

    In this long-awaited sequel to "Inside/Outside: Teacher Research and Knowledge", two leaders in the field of practitioner research offer a radically different view of the relationship of knowledge and practice and of the role of practitioners in educational change. In their new book, the authors put forward the notion of inquiry as stance as a…

  15. Stylizing Voices, Stances, and Identities Related to Medium of Education in India

    ERIC Educational Resources Information Center

    Sandhu, Priti

    2015-01-01

    This study analyzes the narrative-based interview data of three Indian women to examine the manner in which they utilize stylization to construct identity-rich, ideological stances related to discriminatory discourses of Hindi and English medium education in the linguistically rich, albeit complex, present-day context of India. Stylization is…

  16. Argument or Evidence? Disciplinary Variation in the Use of the Noun "that" Pattern in Stance Construction

    ERIC Educational Resources Information Center

    Charles, Maggie

    2007-01-01

    This paper uses a corpus approach to investigate disciplinary variation in the construction of stance using nouns which are followed by "that" and a complement clause, "e.g. the argument that the Justices exhibit strategic behaviour..." Two corpora of theses written in English are examined: approximately 190,000 words in politics/international

  17. Argument or Evidence? Disciplinary Variation in the Use of the Noun "that" Pattern in Stance Construction

    ERIC Educational Resources Information Center

    Charles, Maggie

    2007-01-01

    This paper uses a corpus approach to investigate disciplinary variation in the construction of stance using nouns which are followed by "that" and a complement clause, "e.g. the argument that the Justices exhibit strategic behaviour..." Two corpora of theses written in English are examined: approximately 190,000 words in politics/international…

  18. Ethical Considerations for Psychologists Taking a Public Stance on Controversial Issues: The Balance Between Personal and Professional Life

    PubMed Central

    Haeny, Angela M.

    2014-01-01

    Previous literature has documented the general issues psychologists often face while balancing their personal and professional lives. The struggle stems from attempting to satisfy the need to maintain a life outside of work while having the professional obligation to follow the American Psychological Association’s (APA’s) Ethical Principles of Psychologists and Code of Conduct (Ethics Code) to prevent their personal lives from interfering with their professional roles and relationships. The present paper analyzes the subject of psychologists taking a public position on controversial public issues. Although the APA Ethics Code does not restrict how psychologists conduct themselves during their personal time, taking a public stance on a controversial issue could potentially strain professional relationships and inadvertently reflect negatively on the profession. The present paper examines ethical issues that a) should be taken into account before psychologists take a public position on a controversial issue, and b) are in conflict with APA’s Ethics Code or current research. PMID:25342876

  19. Brain activation patterns during imagined stance and locomotion in functional magnetic resonance imaging.

    PubMed

    Jahn, Klaus; Deutschländer, Angela; Stephan, Thomas; Strupp, Michael; Wiesmann, Martin; Brandt, Thomas

    2004-08-01

    Posture and gait are sensorimotor actions that involve peripheral, spinal, and supraspinal structures. To investigate brain activity during stance and locomotion, 13 healthy subjects were asked to stand, walk, run, and lie down; subsequently, they were trained to imagine standing, walking, running, and lying [imagined lying as rest condition in functional magnetic resonance imaging (fMRI)]. Separate and distinct activation/deactivation patterns were found for the three imagined conditions: (1) standing imagery was associated with activation in the thalamus, basal ganglia, and cerebellar vermis; (2) walking imagery was associated with activation in the parahippocampal and fusiform gyri (areas involved in visuospatial navigation), occipital visual areas, and in the cerebellum; (3) running imagery caused a predominantly cerebellar activation in the vermis and adjacent hemispheres (six times larger than during imagination of walking or standing), but activations in the parahippocampal and fusiform gyri were smaller than during walking. Deactivations were found for walking and running, but not for standing imagery. They were located in the vestibular (posterior insula, superior temporal gyrus, supramarginal gyrus) and somatosensory (postcentral gyrus) cortex with right-hemispheric dominance. These findings support the concept of a hierarchical organization of posture and locomotion. Automated locomotion, for example, running, is based on spinal generators whose pace is driven by the cerebellar locomotor region. Deactivation in the vestibular and somatosensory cortex prevents adverse interactions with the optimized spinal pattern and sensory signals; this confirms earlier findings of a multisensory inhibition during unhindered locomotion. During slow walking, spatial navigation, mediated by the parahippocampal cortex, becomes more important. Postural control during standing involves a low intensity cerebellar activity and sensorimotor control via the thalamus and basal ganglia. PMID:15275928

  20. Evaluation of the EMG activity of the long back muscle during induced back movements at stance.

    PubMed

    Peham, C; Frey, A; Licka, T; Scheidl, M

    2001-04-01

    In this study we investigated the activity of the main back muscle (Musculus longissimus) by surface electromyography (EMG) during induced extension and lateral flexion at stance. Measurements were taken of 15 horses (age 5-20 years, 450-700 kg bwt) without signs of back pain. Reflecting markers were placed on the head, spinous processes of T5, T12, T16, L3 and on 2 of the sacral bones. The surface EMG electrodes were situated on the Musculus longissimus on both sides of the dorsal spinous processes of T12, T16 and L3. In all horses and all movements (extension, lateral flexion to the left and right), the EMG on both sides of the dorsal spinous process of T12 had the highest, and the EMG on both sides of the spinous process of L3, the lowest amplitude (30% of T12). At T16 the amplitude of the EMG signal was 60% of that at T12. There was no time shift between the EMG signals at the different locations (T12, T16, L3). There was a very high correlation between motion and amplitude of the EMG signal of extension, with correlation coefficients of 0.78 at L3, 0.80 at T16 and 0.75 at T12. The correlation of the lateral flexion between amplitude of the EMG and motion was lower, with 0.38 at L3, 0.43 at T16 and 0.39 at T12. This investigation showed that the EMG of the Musculus longissimus during spinal reflexes should be derived on both sides of T12, because this is important for the clinical use of surface EMG. PMID:11721561

  1. Neural Correlates of Task Cost for Stance Control with an Additional Motor Task: Phase-Locked Electroencephalogram Responses

    PubMed Central

    Hwang, Ing-Shiou; Huang, Cheng-Ya

    2016-01-01

    With appropriate reallocation of central resources, the ability to maintain an erect posture is not necessarily degraded by a concurrent motor task. This study investigated the neural control of a particular postural-suprapostural procedure involving brain mechanisms to solve crosstalk between posture and motor subtasks. Participants completed a single posture task and a dual-task while concurrently conducting force-matching and maintaining a tilted stabilometer stance at a target angle. Stabilometer movements and event-related potentials (ERPs) were recorded. The added force-matching task increased the irregularity of postural response rather than the size of postural response prior to force-matching. In addition, the added force-matching task during stabilometer stance led to marked topographic ERP modulation, with greater P2 positivity in the frontal and sensorimotor-parietal areas of the N1-P2 transitional phase and in the sensorimotor-parietal area of the late P2 phase. The time-frequency distribution of the ERP primary principal component revealed that the dual-task condition manifested more pronounced delta (1–4 Hz) and beta (13–35 Hz) synchronizations but suppressed theta activity (4–8 Hz) before force-matching. The dual-task condition also manifested coherent fronto-parietal delta activity in the P2 period. In addition to a decrease in postural regularity, this study reveals spatio-temporal and temporal-spectral reorganizations of ERPs in the fronto-sensorimotor-parietal network due to the added suprapostural motor task. For a particular set of postural-suprapostural task, the behavior and neural data suggest a facilitatory role of autonomous postural response and central resource expansion with increasing interregional interactions for task-shift and planning the motor-suprapostural task. PMID:27010634

  2. Dominant side in single-leg stance stability during floor oscillations at various frequencies

    PubMed Central

    2014-01-01

    Background We investigated lateral dominance in the postural stability of single-leg stance with anteroposterior floor oscillations at various frequencies. Methods Thirty adults maintained a single-leg stance on a force platform for 20 seconds per trial. Trials were performed with no oscillation (static condition) and with anteroposterior floor oscillations (2.5-cm amplitude) at six frequencies: 0.25, 0.5, 0.75, 1.0, 1.25 and 1.5 Hz (dynamic condition). A set of three trials was performed on each leg in each oscillation frequency in random order. The mean speed of the center of pressure in the anteroposterior direction (CoPap) was calculated as an index of postural stability, and frequency analysis of CoPap sway was performed. Footedness for carrying out mobilizing activities was assessed with a questionnaire. Results CoPap speed exponentially increased as oscillation frequency increased in both legs. The frequency analysis of CoPap showed a peak <0.3 Hz at no oscillation. The frequency components at 0.25-Hz oscillation included common components with no oscillation and those at 1.5-Hz oscillation showed the maximum amplitude among all conditions. Postural stability showed no significant difference between left- and right-leg stance at no oscillation and oscillations ≤1.25 Hz, but at 1.5-Hz oscillation was significantly higher in the right-leg stance than in the left-leg stance. For the lateral dominance of postural stability at individual levels, the lateral difference in postural stability at no oscillation was positively correlated with that at 0.25-Hz oscillation (r = 0.51) and negatively correlated with that at 1.5-Hz oscillation (r = -0.53). For 70% of subjects, the dominant side of postural stability was different at no oscillation and 1.5-Hz oscillation. In the subjects with left- or right-side dominance at no oscillation, 94% or 38% changed their dominant side at 1.5-Hz oscillation, with a significant difference between these percentages. In the 1.5-Hz oscillation, 73% of subjects had concordance between the dominant side of postural stability and that of mobilizing footedness. Conclusion In static conditions, there was no lateral dominance of stability during single-leg stance. At 1.5-Hz oscillation, the highest frequency, right-side dominance of postural stability was recognized. Functional role in supporting leg may be divided between left and right legs according to the change of balance condition from static to dynamic. PMID:25127541

  3. Speaking "Common Sense" about the Soviet Threat: Reagan's Rhetorical Stance.

    ERIC Educational Resources Information Center

    Ivie, Robert L.

    Although for the 15 years preceding his election as President of the United States Ronald Reagan muted his anti-Soviet rhetoric in order to achieve political power, since his election he has returned to anti-Sovietism in an effort to redirect American foreign policy against the Soviets. At the same time, however, he employs a rhetorical strategy…

  4. Postural stability deficits during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects.

    PubMed

    Dingenen, Bart; Janssens, Luc; Claes, Steven; Bellemans, Johan; Staes, Filip F

    2015-06-01

    The goal of this study was to evaluate postural stability during the transition from double-leg stance (DLS) to single-leg stance (SLS) in anterior cruciate ligament reconstructed (ACLR) (n=20) and non-injured control subjects (n=20). All ACLR subjects had fully returned to their pre-injury sport participation. Both groups were similar for age, gender, height, weight, body mass index and activity level. Spatiotemporal center of pressure outcomes of both legs of each subject were measured during the transition from DLS to SLS in eyes open and eyes closed conditions. Movement speed was standardized. The center of pressure displacement after a new stability point was reached during the SLS phase was significantly increased in the ACLR group compared to the control group in the eyes closed condition (P=.001). No significant different postural stability outcomes were found between the operated and non-operated legs. In conclusion, the ACLR group showed postural stability deficits, indicating that these persons may have a decreased ability to stabilize their body after the internal postural perturbation created by the transition from DLS to SLS. The non-operated leg may not be the best reference when evaluating postural stability of the operated leg after ACLR, as no differences were found between legs. PMID:25744596

  5. Constructing language normativity through the animation of stance in Spanish-language medical consultations.

    PubMed

    Vickers, Caroline H; Deckert, Sharon K; Goble, Ryan

    2014-01-01

    The purpose of this study is to examine the construction of language normativity as medical providers interact with patients and animate stance within Spanish-language medical consultations. The context of the study is a clinic in which providers use Spanish to communicate with monolingual Spanish-speaking patients. This clinic is in the United States, an English-speaking macro-societal context. Findings indicate that providers who are second-language users of Spanish animate stance and interact with patients in ways such that English is constructed as normative and Spanish as marked. Implications include the need to consider how the construction of language normativity within medical consultations affects health outcomes. PMID:24156518

  6. Unilateral Stance Strategies of Athletes With ACL Deficiency

    PubMed Central

    Di Stasi, Stephanie L.; Hartigan, Erin H.; Snyder-Mackler, Lynn

    2013-01-01

    Aberrant movement strategies are characteristic of ACL-deficient athletes with recurrent knee instability (non-copers), and may instigate premature or accelerate joint degradation. Biomechanical evaluation of kinematic changes over time may elucidate noncopers’ responses to neuromuscular intervention and ACL reconstruction (ACLR). Forty noncopers were randomized into a perturbation group or a strength training only group. We evaluated the effects of perturbation training, and then gender on knee angle and tibial position during a unilateral standing task before and after ACLR. No statistically significant interactions were found. Before surgery, the strength training only group demonstrated knee angle asymmetry, but 6 months after ACLR, both groups presented with similar knee flexion between limbs. Aberrant and asymmetrical tibial position was found only in females following injury and ACLR. Neither treatment group showed distinct unilateral standing strategies following intervention; however, males and female noncopers appear to respond uniquely to physical therapy and surgery. PMID:22983931

  7. The influence of gait stance on pedestrian lower limb injury risk.

    PubMed

    Li, Guibing; Yang, Jikuang; Simms, Ciaran

    2015-12-01

    The effect of pedestrian gait on lower limb kinematics and injuries has not been analyzed. The purpose of this paper was therefore to investigate the effect of pedestrian gait on kinematics and injury risk to the lower limbs using the Total Human Model for Safety adult male pedestrian model together with FE models of vehicle front structures. The modeling results indicate that the tibia and femur cortical bone von-Mises stress and the lateral knee bending angle of an adult pedestrian are strongly dependent on the gait stance when struck by both a sedan car and an SUV at 40km/h. The gait analysis shows that generally the leg of an adult pedestrian has lower injury risk when the knee is flexed and linear regressions show high negative correlation between knee flexion angle during impact and knee lateral bending angle and also high negative correlation between lower leg axial rotation during impact and knee lateral bending angle. Furthermore, in some gait stances a self-contact between the legs occurs, and the peak bones stresses and knee shearing displacement in the leg are then increased. Assessment of pedestrian lower limb injury should take account of these gait stance effects. PMID:26397198

  8. DOES RECTUS FEMORIS TRANSFER INCREASE KNEE FLEXION DURING STANCE PHASE IN CEREBRAL PALSY?

    PubMed Central

    de Morais, Mauro César; Blumetti, Francesco Camara; Kawamura, Cátia Miyuki; Lopes, José Augusto Fernandes; Neves, Daniella Lins; Cardoso, Michelle de Oliveira

    2016-01-01

    ABSTRACT Objective: To evaluate whether distal rectus femoris transfer (DRFT) is related to postoperative increase of knee flexion during the stance phase in cerebral palsy (CP). Methods: The inclusion criteria were Gross Motor Function Classification System (GMFCS) levels I-III, kinematic criteria for stiff-knee gait at baseline, and individuals who underwent orthopaedic surgery and had gait analyses performed before and after intervention. The patients included were divided into the following two groups: NO-DRFT (133 patients), which included patients who underwent orthopaedic surgery without DRFT, and DRFT (83 patients), which included patients who underwent orthopaedic surgery that included DRFT. The primary outcome was to evaluate in each group if minimum knee flexion in stance phase (FMJFA) changed after treatment. Results: The mean FMJFA increased from 13.19° to 16.74° (p=0.003) and from 10.60° to 14.80° (p=0.001) in Groups NO-DRFT and DRFT, respectively. The post-operative FMJFA was similar between groups NO-DRFT and DRFT (p=0.534). The increase of FMJFA during the second exam (from 13.01° to 22.51°) was higher among the GMFCS III patients in the DRFT group (p<0.001). Conclusion: In this study, DRFT did not generate additional increase of knee flexion during stance phase when compared to the control group. Level of Evidence III, Retrospective Comparative Study. PMID:26997910

  9. From relational ontology to transformative activist stance on development and learning: expanding Vygotsky's (CHAT) project

    NASA Astrophysics Data System (ADS)

    Stetsenko, Anna

    2008-07-01

    This paper offers steps towards overcoming current fragmentation within sociocultural approaches by expansively reconstructing a broad dialectical view on human development and learning (drawing on Vygotsky's project) underwritten by ideology of social justice. The common foundation for sociocultural approaches is developed by dialectically supplanting relational ontology with the notion that collaborative purposeful transformation of the world is the core of human nature and the principled grounding for learning and development. An activist transformative stance suggests that people come to know themselves and their world as well as ultimately come to be human in and through (not in addition to) the processes of collaboratively transforming the world in view of their goals. This means that all human activities (including psychological processes and the self) are instantiations of contributions to collaborative transformative practices that are contingent on both the past and the vision for the future and therefore are profoundly imbued with ideology, ethics, and values. And because acting, being, and knowing are seen from a transformative activist stance as all rooted in, derivative of, and instrumental within a collaborative historical becoming, this stance cuts across and bridges the gaps (a) between individual and social and (b) among ontological, epistemological, and moral-ethical (ideological) dimensions of activity.

  10. Postural Instability Detection: Aging and the Complexity of Spatial-Temporal Distributional Patterns for Virtually Contacting the Stability Boundary in Human Stance

    PubMed Central

    Kilby, Melissa C.; Slobounov, Semyon M.; Newell, Karl M.

    2014-01-01

    Falls among the older population can severely restrict their functional mobility and even cause death. Therefore, it is crucial to understand the mechanisms and conditions that cause falls, for which it is important to develop a predictive model of falls. One critical quantity for postural instability detection and prediction is the instantaneous stability of quiet upright stance based on motion data. However, well-established measures in the field of motor control that quantify overall postural stability using center-of-pressure (COP) or center-of-mass (COM) fluctuations are inadequate predictors of instantaneous stability. For this reason, 2D COP/COM virtual-time-to-contact (VTC) is investigated to detect the postural stability deficits of healthy older people compared to young adults. VTC predicts the temporal safety margin to the functional stability boundary ( =  limits of the region of feasible COP or COM displacement) and, therefore, provides an index of the risk of losing postural stability. The spatial directions with increased instability were also determined using quantities of VTC that have not previously been considered. Further, Lempel-Ziv-Complexity (LZC), a measure suitable for on-line monitoring of stability/instability, was applied to explore the temporal structure or complexity of VTC and the predictability of future postural instability based on previous behavior. These features were examined as a function of age, vision and different load weighting on the legs. The primary findings showed that for old adults the stability boundary was contracted and VTC reduced. Furthermore, the complexity decreased with aging and the direction with highest postural instability also changed in aging compared to the young adults. The findings reveal the sensitivity of the time dependent properties of 2D VTC to the detection of postural instability in aging, availability of visual information and postural stance and potential applicability as a predictive model of postural instability during upright stance. PMID:25295589

  11. The intentional stance as structure learning: a computational perspective on mindreading.

    PubMed

    Dindo, Haris; Donnarumma, Francesco; Chersi, Fabian; Pezzulo, Giovanni

    2015-10-01

    Recent theories of mindreading explain the recognition of action, intention, and belief of other agents in terms of generative architectures that model the causal relations between observables (e.g., observed movements) and their hidden causes (e.g., action goals and beliefs). Two kinds of probabilistic generative schemes have been proposed in cognitive science and robotics that link to a "theory theory" and "simulation theory" of mindreading, respectively. The former compares perceived actions to optimal plans derived from rationality principles and conceptual theories of others' minds. The latter reuses one's own internal (inverse and forward) models for action execution to perform a look-ahead mental simulation of perceived actions. Both theories, however, leave one question unanswered: how are the generative models - including task structure and parameters - learned in the first place? We start from Dennett's "intentional stance" proposal and characterize it within generative theories of action and intention recognition. We propose that humans use an intentional stance as a learning bias that sidesteps the (hard) structure learning problem and bootstraps the acquisition of generative models for others' actions. The intentional stance corresponds to a candidate structure in the generative scheme, which encodes a simplified belief-desire folk psychology and a hierarchical intention-to-action organization of behavior. This simple structure can be used as a proxy for the "true" generative structure of others' actions and intentions and is continuously grown and refined - via state and parameter learning - during interactions. In turn - as our computational simulations show - this can help solve mindreading problems and bootstrap the acquisition of useful causal models of both one's own and others' goal-directed actions. PMID:26168854

  12. Non-Gaussian center-of-pressure velocity distribution during quiet stance

    NASA Astrophysics Data System (ADS)

    Santos, E. S. D.; Picoli, S.; Deprá, P. P.; Mendes, R. S.

    2015-02-01

    In the present study, we investigate patterns in the postural sway that characterize the static balance in human beings. To measure the postural sway, sixteen healthy young subjects performed quiet stance tasks providing the center-of-pressure (COP) trajectories. From these trajectories, we obtained the COP velocities. We verified that the velocity distributions exhibit non-normal behavior and can be approximated by generalized Gaussians with fat tails. We also discuss possible implications of modeling COP velocity by using generalized Fokker-Planck equations related to Tsallis statistics and Richardson anomalous diffusion.

  13. Development of a sliding mode control model for quiet upright stance.

    PubMed

    Zhang, Hongbo; Nussbaum, Maury A; Agnew, Michael J

    2016-02-01

    Human upright stance appears maintained or controlled intermittently, through some combination of passive and active ankle torques, respectively representing intrinsic and contractile contributions of the ankle musculature. Several intermittent postural control models have been proposed, though it has been challenging to accurately represent actual kinematics and kinetics and to separately estimate passive and active ankle torque components. Here, a simplified single-segment, 2D (sagittal plane) sliding mode control model was developed for application to track kinematics and kinetics during upright stance. The model was implemented and evaluated using previous experimental data consisting of whole body angular kinematics and ankle torques. Tracking errors for the whole-body center-of-mass (COM) angle and angular velocity, as well as ankle torque, were all within ∼10% of experimental values, though tracking performance for COM angular acceleration was substantially poorer. The model also enabled separate estimates of the contributions of passive and active ankle torques, with overall contributions estimated here to be 96% and 4% of the total ankle torque, respectively. Such a model may have future utility in understanding human postural control, though additional work is needed, such as expanding the model to multiple segments and to three dimensions. PMID:26810735

  14. Tandem Stance Avoidance Using Adaptive and Asymmetric Admittance Control for Fall Prevention.

    PubMed

    Nakagawa, Shotaro; Hasegawa, Yasuhisa; Fukuda, Toshio; Kondo, Izumi; Tanimoto, Masanori; Di, Pei; Huang, Jian; Huang, Qiang

    2016-05-01

    Fall prevention is one of the most important functions of walking assistance devices for user's safety. It is preferable that these devices prevent the user from being in the state where the risk of falling is high rather than helping them recovering from falling motion. During turning, when the user is in the tandem stance, a state where both legs form a line along walking direction, a support base that is surrounded by two legs becomes small, and a stability margin becomes small. This paper therefore aims to prevent the tandem stance by using nonwearable robot "intelligent cane" for the elderly or physically challenged person. Generally, the behavior of the lower limb follows the upper body turning. This paper therefore introduces a cane robot control method which constrains the behavior of user's upper body. By adjusting an admittance parameter of the robot according to the positions of a support leg, the robot resists to turn while a support leg is on the same side of the turning direction. A swing leg on the turning direction side therefore freely moves to the turning direction, while a swing leg on the opposite direction side of turning hardly move to the turning direction. PMID:25955991

  15. Unexpected Fascicle Length Changes In Denervated Feline Soleus Muscle During Stance Phase Of Walking

    PubMed Central

    Mehta, Ricky; Maas, Huub; Gregor, Robert J.; Prilutsky, Boris I.

    2015-01-01

    After surgical repair of traumatically severed peripheral nerves, associated muscles are paralyzed for weeks. Little is known about fascicle length changes in paralyzed muscles during locomotion. The aim of this study was to investigate to what extent, if any, muscle fascicles of denervated feline soleus (SO) change length during stance of walking when intact SO synergists are actively contracting. Hindlimb kinematics, SO fascicle and muscle-tendon unit (MTU) length, and EMG activity of SO, lateral gastrocnemius (LG) and medial gastrocnemius (MG) were measured during level and slope walking in adult cats. Measurements were taken before and 1–2 weeks following SO-LG denervation. Unexpectedly, SO fascicle lengthening and shortening during stance in all walking conditions were evident after denervation. The greatest SO fascicle shortening (17.3 ± 2.2% of a reference length) and least fascicle lengthening (1.5 ± 0.8%) after denervation were found during upslope walking, where MG EMG activity was greatest across slopes (P < 0.05) and greatest discrepancies between post denervation SO fascicle and MTU length changes occurred. These findings suggest that myofascial linkages between denervated SO and its active synergists might affect its fascicle length changes. Further studies are needed to directly test this suggestion. PMID:26635206

  16. The Effect of Continuous and Discretized Presentations of Concurrent Augmented Visual Biofeedback on Postural Control in Quiet Stance.

    PubMed

    D'Anna, Carmen; Schmid, Maurizio; Bibbo, Daniele; Bertollo, Maurizio; Comani, Silvia; Conforto, Silvia

    2015-01-01

    The purpose of this study was to evaluate the effect of a continuous and a discretized Visual Biofeedback (VBF) on balance performance in upright stance. The coordinates of the Centre of Pressure (CoP), extracted from a force plate, were processed in real-time to implement the two VBFs, administered to two groups of 12 healthy participants. In the first group, a representation of the CoP was continuously shown, while in the second group, the discretized VBF was provided at an irregular frequency (that depended on the subject's performance) by displaying one out of a set of five different emoticons, each corresponding to a specific area covered by the current position of the CoP. In the first case, participants were asked to maintain a white spot within a given square area, whereas in the second case they were asked to keep the smiling emoticon on. Trials with no VBF were administered as control. The effect of the two VBFs on balance was studied through classical postural parameters and a subset of stabilogram diffusion coefficients. To quantify the amount of time spent in stable conditions, the percentage of time during which the CoP was inside the stability area was calculated. Both VBFs improved balance maintainance as compared to the absence of any VBF. As compared to the continuous VBF, in the discretized VBF a significant decrease of sway path, diffusion and Hurst coefficients was found. These results seem to indicate that a discretized VBF favours a more natural postural behaviour by promoting a natural intermittent postural control strategy. PMID:26196518

  17. The Effect of Continuous and Discretized Presentations of Concurrent Augmented Visual Biofeedback on Postural Control in Quiet Stance

    PubMed Central

    D’Anna, Carmen; Schmid, Maurizio; Bibbo, Daniele; Bertollo, Maurizio; Comani, Silvia; Conforto, Silvia

    2015-01-01

    The purpose of this study was to evaluate the effect of a continuous and a discretized Visual Biofeedback (VBF) on balance performance in upright stance. The coordinates of the Centre of Pressure (CoP), extracted from a force plate, were processed in real-time to implement the two VBFs, administered to two groups of 12 healthy participants. In the first group, a representation of the CoP was continuously shown, while in the second group, the discretized VBF was provided at an irregular frequency (that depended on the subject's performance) by displaying one out of a set of five different emoticons, each corresponding to a specific area covered by the current position of the CoP. In the first case, participants were asked to maintain a white spot within a given square area, whereas in the second case they were asked to keep the smiling emoticon on. Trials with no VBF were administered as control. The effect of the two VBFs on balance was studied through classical postural parameters and a subset of stabilogram diffusion coefficients. To quantify the amount of time spent in stable conditions, the percentage of time during which the CoP was inside the stability area was calculated. Both VBFs improved balance maintainance as compared to the absence of any VBF. As compared to the continuous VBF, in the discretized VBF a significant decrease of sway path, diffusion and Hurst coefficients was found. These results seem to indicate that a discretized VBF favours a more natural postural behaviour by promoting a natural intermittent postural control strategy. PMID:26196518

  18. Assessment of AK (Above Knee) Prosthesis with Different Ankle Assembly Using GRF Pattern in Stance Phase

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Min; Kim, Sung-Jae; Bae, Ha-Suk

    In this study, ground reaction force (GRF), absolute symmetry index (ASI) and coefficient of variation (CV) of fixed, single-axis and multi-axis prosthetic ankle assemblies were investigated by biomechanical evaluation of above knee amputees. In the experiments, 37 normal male volunteers, two male and two female Above Knee (AK) amputees GRF data were tested with fixed, single-axis and multi-axis prosthetic ankle assembly. A gait analysis was carried out to derive the ratio of GRF to weight as the percentage of total stance phase for ten points. The results showed that fixed-axis ankle assembly was superior to other two ankle assemblies for forwarding and braking forces. Multi-axis ankle was relatively superior to other two ankle assemblies for gait balancing and movement of the mass center. Single-axis ankle was relatively superior to the other two ankle assemblies for CV and ASI of GRF.

  19. Recovery from a Simulated Fall and Quiet Stance Stability After Long-Duration Space Flight

    NASA Technical Reports Server (NTRS)

    Kofman, I. S.; Reschke, M. F.; Cerisano, J. M.; Fisher, E. A.; May-Phillips, T. R.; Rukavishnikov, I. V.; Kitov, V. V.; Lysova, N. Yu; Lee, S. M. C.; Stenger, M. B.; Bloomberg, J. J.; Mulavara, A. P.; Tomilovskaya, E. S.; Kozlovskaya, I. B.

    2016-01-01

    Most of the ISS crew members who attempted the demanding RFF task within1-5 hours after landing were able to complete it and perform the remaining PFT tasks. This finding was important as it allowed us to transition from PFT to the full up Field Test study which includes all of PFT and several additional objectives. Long-duration spaceflight impairs crewmembers' locomotion and balance functions, which will significantly limit their abilities to perform complex tasks during the early adaptation period. Crewmember safety may also be affected if they have to spend additional 10-15 seconds to get up during an emergency egress, for example. Performance of the RFF task (both the transition and quiet stance parts) improves at a fast rate during the first day after flight. We believe that the PFT tasks performed by the crewmembers, actually accelerate the recovery of their sensorimotor function. Additional data mining and analysis will need to be conducted to confirm this hypothesis

  20. Knowing When to Doubt: Developing a Critical Stance When Learning From Others

    PubMed Central

    Mills, Candice M.

    2013-01-01

    Children may be biased towards accepting information as true, but the fact remains that children are exposed to misinformation from many sources, and mastering the intricacies of doubt is necessary. The current article examines this issue, focusing on understanding developmental changes and consistencies in children’s ability to take a critical stance towards information. Research is reviewed on children’s ability to detect ignorance, inaccuracy, incompetence, deception, and distortion. Particular emphasis is placed on what this research indicates about how children are reasoning about when to trust and when to doubt. The remainder of the article proposes a framework to evaluate preexisting research and encourage further research, closing with a discussion of several other overarching questions that need to be considered in order to develop a model to explain developmental, individual, and situational differences in children’s ability to evaluate information. PMID:22889395

  1. COORDINATED, MULTI-JOINT, FATIGUE-RESISTANT FELINE STANCE PRODUCED WITH INTRAFASCICULAR HIND LIMB NERVE STIMULATION

    PubMed Central

    Normann, R A; Dowden, B R; Frankel, M A; Wilder, A M; Hiatt, S D; Ledbetter, N M; Warren, D A; Clark, G A

    2012-01-01

    The production of graceful skeletal movements requires coordinated activation of multiple muscles that produce torques around multiple joints. The work described herein is focused on one such movement, stance, that requires coordinated activation of extensor muscles acting around the hip, knee and ankle joints. The forces evoked in these muscles by external stimulation all have a complex dependence on muscle length and shortening velocities, and some of these muscles are bi-articular. In order to recreate sit-to-stand maneuvers in the anesthetized feline, we excited the hind limb musculature using intrafascicular multielectrode stimulation (IFMS) of the muscular branch of the sciatic nerve, the femoral nerve, and the main branch of the sciatic nerve. Stimulation was achieved with either acutely or chronically implanted Utah Slanted Electrode Arrays (USEAs) via subsets of electrodes 1) that activated motor units in the extensor muscles of the hip, knee, and ankle joints, 2) that were able to evoke large extension forces, and 3) that manifested minimal coactivation of the targeted motor units. Three hind limb force-generation strategies were investigated, including sequential activation of independent motor units to increase force, and interleaved or simultaneous IFMS of three sets of six or more USEA electrodes that excited the hip, knee, and ankle extensors. All force-generation strategies evoked stance, but the interleaved IFMS strategy also reduced muscle fatigue produced by repeated sit-to-stand maneuvers compared with fatigue produced by simultaneous activation of different motor neuron pools. These results demonstrate the use of interleaved IFMS as a means to recreate coordinated, fatigue-resistant multi-joint muscle forces in the unilateral hind limb. This muscle activation paradigm could provide a promising neuroprosthetic approach for the restoration of sit-to-stand transitions in individuals who are paralyzed by spinal cord injury, stroke, or disease. PMID:22414699

  2. Coordinated, multi-joint, fatigue-resistant feline stance produced with intrafascicular hind limb nerve stimulation

    NASA Astrophysics Data System (ADS)

    Normann, R. A.; Dowden, B. R.; Frankel, M. A.; Wilder, A. M.; Hiatt, S. D.; Ledbetter, N. M.; Warren, D. A.; Clark, G. A.

    2012-04-01

    The production of graceful skeletal movements requires coordinated activation of multiple muscles that produce torques around multiple joints. The work described herein is focused on one such movement, stance, that requires coordinated activation of extensor muscles acting around the hip, knee and ankle joints. The forces evoked in these muscles by external stimulation all have a complex dependence on muscle length and shortening velocities, and some of these muscles are biarticular. In order to recreate sit-to-stand maneuvers in the anesthetized feline, we excited the hind limb musculature using intrafascicular multielectrode stimulation (IFMS) of the muscular branch of the sciatic nerve, the femoral nerve and the main branch of the sciatic nerve. Stimulation was achieved with either acutely or chronically implanted Utah Slanted Electrode Arrays (USEAs) via subsets of electrodes (1) that activated motor units in the extensor muscles of the hip, knee and ankle joints, (2) that were able to evoke large extension forces and (3) that manifested minimal coactivation of the targeted motor units. Three hind limb force-generation strategies were investigated, including sequential activation of independent motor units to increase force, and interleaved or simultaneous IFMS of three sets of six or more USEA electrodes that excited the hip, knee and ankle extensors. All force-generation strategies evoked stance, but the interleaved IFMS strategy also reduced muscle fatigue produced by repeated sit-to-stand maneuvers compared with fatigue produced by simultaneous activation of different motor neuron pools. These results demonstrate the use of interleaved IFMS as a means to recreate coordinated, fatigue-resistant multi-joint muscle forces in the unilateral hind limb. This muscle activation paradigm could provide a promising neuroprosthetic approach for the restoration of sit-to-stand transitions in individuals who are paralyzed by spinal cord injury, stroke or disease.

  3. Adaptive behaviour of the spinal cord in the transition from quiet stance to walking

    PubMed Central

    2012-01-01

    Background Modulation of nociceptive withdrawal reflex (NWR) excitability was evaluated during gait initiation in 10 healthy subjects to investigate how load- and movement-related joint inputs activate lower spinal centres in the transition from quiet stance to walking. A motion analysis system integrated with a surface EMG device was used to acquire kinematic, kinetic and EMG variables. Starting from a quiet stance, subjects were asked to walk forward, at their natural speed. The sural nerve was stimulated and EMG responses were recorded from major hip, knee and ankle muscles. Gait initiation was divided into four subphases based on centre of pressure and centre of mass behaviours, while joint displacements were used to categorise joint motion as flexion or extension. The reflex parameters were measured and compared between subphases and in relation to the joint kinematics. Results The NWR was found to be subphase-dependent. NWR excitability was increased in the hip and knee flexor muscles of the starting leg, just prior to the occurrence of any movement, and in the knee flexor muscles of the same leg as soon as it was unloaded. The NWR was hip joint kinematics-dependent in a crossed manner. The excitability of the reflex was enhanced in the extensor muscles of the standing leg during the hip flexion of the starting leg, and in the hip flexors of the standing leg during the hip extension of the starting leg. No notable reflex modulation was observed in the ankle muscles. Conclusions Our findings show that the NWR is modulated during the gait initiation phase. Leg unloading and hip joint motion are the main sources of the observed modulation and work in concert to prepare and assist the starting leg in the first step while supporting the contralateral leg, thereby possibly predisposing the lower limbs to the cyclical pattern of walking. PMID:22800397

  4. Postflight Quiet Stance Stability of Astronauts Following Recovery From a Simulated Fall

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Kofman, I. S.; Fisher, E. A.; Cerisano, J. M.; Lawrence, E. L.; Peters, B. T.; Harm, D. L.; Kulecz, W.; Mulavara, A. P.; Fiedler, M. J.; Bloomberg, J. J.

    2010-01-01

    INTRODUCTION: Astronauts returning from space flight universally present with postural ataxia. Throughout the Space Shuttle Program, measurement of ataxia has concentrated on sway in the anterior-posterior plane. Implementation of an interdisciplinary pre- and postflight study (Functional Task Test, FTT) designed to evaluate both astronaut postflight functional performance and related physiological changes has allowed the investigation of postural instability by characterizing dynamic stabilographic sway patterns. METHODS: Six astronauts from short-duration (Shuttle) and three from long-duration (ISS) flights were required to recover from a simulated fall. Subjects with eyes open, wearing running shoes lay prone on the floor for 2 minutes and then quickly stood up, maintained a quiet stance for 3 minutes, arms relaxed along the side of the body, and feet comfortably placed on the force plate. Crewmembers were tested twice before flight, on landing day (Shuttle only), and 1, 6, and 30 days after flight. Anterior-posterior (AP) and medial-lateral (ML) center-of-pressure (COP) coordinates were calculated from the ground reaction forces collected at 500 Hz. The 3-minute quiet stance trial was broken into three 1-minute segments for stabilogram diffusion analysis. A mean sway speed (rate of change of COP displacement) was also calculated as an additional postural stability parameter. RESULTS/CONCLUSION: While there was considerable variation, most of crewmembers tested exhibited increased stochastic activity evidenced by larger short-term COP diffusion coefficients postflight in both the AP and ML planes, suggesting significant changes in postural control mechanisms, particularly control of lower limb muscle function. As expected, postural instability of ISS astronauts on the first day postflight was similar to that of Shuttle crewmembers on landing day. Recoveries of stochastic activity and mean sway speed to baseline levels were typically observed by the 30th day postflight for both long-duration and short-duration crewmembers. Dynamic postural stability characteristics obtained in this low-impact study complement the data measured with computerized dynamic posturography.

  5. A longitudinal study of impact and early stance loads during gait following arthroscopic partial meniscectomy.

    PubMed

    Hall, Michelle; Wrigley, Tim V; Metcalf, Ben R; Hinman, Rana S; Dempsey, Alasdair R; Mills, Peter M; Cicuttini, Flavia M; Lloyd, David G; Bennell, Kim L

    2014-09-22

    People following arthroscopic partial medial meniscectomy (APM) are at increased risk of developing knee osteoarthritis. High impact loading and peak loading early in the stance phase of gait may play a role in the pathogenesis of knee osteoarthritis. This was a secondary analysis of longitudinal data to investigate loading-related indices at baseline in an APM group (3 months post-surgery) and a healthy control group, and again 2 years later (follow-up). At baseline, 82 participants with medial APM and 38 healthy controls were assessed, with 66 and 23 re-assessed at follow-up, respectively. Outcome measures included: (i) heel strike transient (HST) presence and magnitude, (ii) maximum loading rate, (iii) peak vertical force (Fz) during early stance. At baseline, maximum loading rate was lower in the operated leg (APM) and non-operated leg (non-APM leg) compared to controls (p ≤ 0.03) and peak Fz was lower in the APM leg compared to non-APM leg (p ≤ 0.01). Over 2 years, peak Fz increased in the APM leg compared to the non-APM leg and controls (p ≤ 0.01). Following recent APM, people may adapt their gait to protect the operated knee from excessive loads, as evidenced by a lower maximum loading rate in the APM leg compared to controls, and a reduced peak Fz in the APM leg compared to the non-APM leg. No differences at follow-up may suggest an eventual return to more typical gait. However, the increase in peak Fz in the APM leg may be of concern for long-term joint health given the compromised function of the meniscus. PMID:25169661

  6. Study of stress variations in single-stance and sideways fall using image-based finite element analysis.

    PubMed

    Faisal, Tanvir R; Luo, Yunhua

    2016-05-12

    Image-based finite element analysis (FEA) has been considered an effective computational tool to predict hip fracture risk. The patient specific FEA gives an insight into the inclusive effect of three-dimensional (3D) complex bone geometry, and the distribution of inhomogeneous isotropic material properties in conjunction with loading conditions. The neck region of a femur is primarily the weakest in which fracture is likely to happen, when someone falls. A sideways fall results in the development of greater tensile and compressive stresses, respectively, in the inferior and superior aspects of the femoral neck, whereas the state of stress is reversed in usual gait or stance configuration. Herein, the variations of stresses have been investigated at the femoral neck region considering both single-stance and sideways fall. Finite element models of ten human femora have been generated using Quantitative Computed Tomography (QCT) scan datasets and have been simulated with an equal magnitude of load applied to the aforementioned configurations. Fracture risk indicator, defined as the ratio of the maximum compressive or tensile stress computed at the superior and inferior surfaces to the corresponding yield stress, has been used in this work to measure the variations of fracture risk between single-stance and sideways fall. The average variations of the fracture risk indicators between the fall and stance are at least 24.3% and 8% at the superior and inferior surfaces, respectively. The differences may interpret why sideways fall is more dangerous for the elderly people, causing hip fracture. PMID:27175463

  7. Government Stance and Internal Diversity of Protest: A Comparative Study of Protest against the War in Iraq in Eight Countries

    ERIC Educational Resources Information Center

    Walgrave, Stefaan; Verhulst, Joris

    2009-01-01

    This study tackles the question to what extent the composition of protest events is determined by the stance of governments. Established contextual theories do not formulate propositions on how context affects individual protesters. The article engages in empirically testing whether the macro-context affects the internal diversity of the crowds…

  8. Participation in Peer Response as Activity: An Examination of Peer Response Stances from an Activity Theory Perspective

    ERIC Educational Resources Information Center

    Zhu, Wei; Mitchell, Deborah A.

    2012-01-01

    This article reports a case study that examined English as a Second Language students' peer response stances from an activity theory perspective. More specifically, the study was guided by the constructs of activity and motive/object in Leont'ev's theory. Multiple sources of data were collected from two native Spanish-speaking students enrolled in…

  9. Taking an Evaluative Stance to Decision-Making about Professional Development Options in Early Childhood Education and Care

    ERIC Educational Resources Information Center

    Brownlee, Joanne Lunn; Sumsion, Jennifer; Irvine, Susan; Berthelsen, Donna; Farrell, Ann; Walsh, Kerryann; Ryan, Sharon; Mulhearn, Gerry

    2015-01-01

    This article builds on our ongoing work in conceptualising an "evaluative stance" framework to assist in understanding how leaders in the field of early childhood education and care (ECEC) make decisions about the selection of professional development options for themselves and their staff. It introduces the notion that evaluative…

  10. Reading Sacred Texts in the Classroom: The Alignment between Students and Their Teacher's Interpretive Stances When Reading the Hebrew Bible

    ERIC Educational Resources Information Center

    Hassenfeld, Ziva R.

    2016-01-01

    This study investigated the voices of students interpreting Hebrew Bible texts in one fourth-grade classroom. Through think-alouds on the Biblical text with each student, exit interviews, teacher interviews, and classroom observations, this study found that those students whose interpretive stances were more aligned with the teacher's were given…

  11. The Transformative Power of Taking an Inquiry Stance on Practice: Practitioner Research as Narrative and Counter-Narrative

    ERIC Educational Resources Information Center

    Ravitch, Sharon M.

    2014-01-01

    Within the ever-developing, intersecting, and overlapping contexts of globalization, top-down policy, mandates, and standardization of public and higher education, many conceptualize and position practitioner research as a powerful stance and a tool of social, communal, and educational transformation, a set of methodological processes that…

  12. Connecting Learning and Identity Development through a Transformative Activist Stance: Application in Adolescent Development in a Child Welfare Program

    ERIC Educational Resources Information Center

    Vianna, Eduardo; Stetsenko, Anna

    2011-01-01

    This paper addresses the relationship between identity and learning and how their integration in adolescence is an important part of short- and long-term developmental dynamics. We discuss how social practice theories can be expanded from a position termed "transformative activist stance" that puts emphasis on collaborative practice aimed at…

  13. What Keeps Oncologists From Addressing Palliative Care Early on With Incurable Cancer Patients? An Active Stance Seems Key

    PubMed Central

    Pfeil, Timo A.; Laryionava, Katsiaryna; Reiter-Theil, Stella; Hiddemann, Wolfgang

    2015-01-01

    Background. Sympathetic and frank communication about the terminal nature of advanced cancer is important to improve patients’ prognostic understanding and, thereby, to allow for adjustment of treatment intensity to realistic goals; however, decisions against aggressive treatments are often made only when death is imminent. This qualitative study explores the factors that hinder such communication and reconstructs how physicians and nurses in oncology perceive their roles in preparing patients for end-of-life (EOL) decisions. Methods. Qualitative in-depth interviews were conducted with physicians (n = 12) and nurses (n = 6) working at the Department of Hematology/Oncology at the university hospital in Munich, Germany. The data were analyzed using grounded theory methodology and discussed from a medical ethics perspective. Results. Oncologists reported patients with unrealistic expectations to be a challenge for EOL communication that is especially prominent in comprehensive cancer centers. Oncologists responded to this challenge quite differently by either proactively trying to facilitate advanced care planning or passively leaving the initiative to address preferences for care at the EOL to the patient. A major impediment to the proactive approach was uncertainty about the right timing for EOL discussions and about the balancing the medical evidence against the physician’s own subjective emotional involvement and the patient’s wishes. Conclusion. These findings provide explanations of why EOL communication is often started rather late with cancer patients. For ethical reasons, a proactive stance should be promoted, and oncologists should take on the task of preparing patients for their last phase of life. To do this, more concrete guidance on when to initiate EOL communication is necessary to improve the quality of decision making for advanced cancer patients. PMID:25361623

  14. Sample entropy characteristics of movement for four foot types based on plantar centre of pressure during stance phase

    PubMed Central

    2013-01-01

    Background Motion characteristics of CoP (Centre of Pressure, the point of application of the resultant ground reaction force acting on the plate) are useful for foot type characteristics detection. To date, only few studies have investigated the nonlinear characteristics of CoP velocity and acceleration during the stance phase. The aim of this study is to investigate whether CoP regularity is different among four foot types (normal foot, pes valgus, hallux valgus and pes cavus); this might be useful for classification and diagnosis of foot injuries and diseases. To meet this goal, sample entropy, a measure of time-series regularity, was used to quantify the CoP regularity of four foot types. Methods One hundred and sixty five subjects that had the same foot type bilaterally (48 subjects with healthy feet, 22 with pes valgus, 47 with hallux valgus, and 48 with pes cavus) were recruited for this study. A Footscan® system was used to collect CoP data when each subject walked at normal and steady speed. The velocity and acceleration in medial-lateral (ML) and anterior-posterior (AP) directions, and resultant velocity and acceleration were derived from CoP. The sample entropy is the negative natural logarithm of the conditional probability that a subseries of length m that matches pointwise within a tolerance r also matches at the next point. This was used to quantify variables of CoP velocity and acceleration of four foot types. The parameters r (the tolerance) and m (the matching length) for sample entropy calculation have been determined by an optimal method. Results It has been found that in order to analyze all CoP parameters of velocity and acceleration during the stance phase of walking gait, for each variable there is a different optimal r value. On the contrary, the value m=4 is optimal for all variables. Sample entropies of both velocity and acceleration in AP direction were highly correlated with their corresponding resultant variables for r>0.91. The sample entropy of the velocity in AP direction was moderately correlated with the one of the acceleration in the same direction (r≥0.673), as well as with the resultant acceleration (r≥0.660). The sample entropy of resultant velocity was moderately correlated with the one of the acceleration in AP direction, as well as with the resultant acceleration (for the both r≥0.689). Moderate correlations were found between variables for the left foot and their corresponding variables for the right foot. Sample entropies of AP velocity, resultant velocity, AP acceleration, and resultant acceleration of the right foot as well as AP velocity and resultant velocity of the left foot were, respectively, significantly different among the four foot types. Conclusions It can be concluded that the sample entropy of AP velocity (or the resultant velocity) of the left foot, ML velocity, resultant velocity, ML acceleration and resultant acceleration could serve for evaluation of foot types or selection of appropriate footwear. PMID:24112763

  15. Kinematics and Kinetics of Squat and Deadlift Exercises with Varying Stance Widths

    NASA Technical Reports Server (NTRS)

    DeWitt, John K.; Fincke, Renita S.; Logan, Rachel L.

    2011-01-01

    The primary motion of squat and deadlift exercise involves flexion and extension of the hips, knees, and ankles, but each exercise can be performed with variations in stance width. These variations may result in differing kinematics and ground reaction forces (GRF), which may in turn affect joint loading. PURPOSE: The purpose of this investigation was to compare ankle, knee, and hip kinematics and kinetics of normal squat (NS), wide-stance squat (WS), normal deadlift (ND), and sumo deadlift (SD). We hypothesized that hip joint kinematics and work at each joint would differ between exercise variations. METHODS: Six subjects (3 m/3 f; 70.0 plus or minus 13.7 kg; 168 plus or minus 9.9 cm) performed each lift in normal gravity on the ground-based version of the Advanced Resistive Exercise Device (ARED) used on the International Space Station. The ARED provided resistance with a combination vacuum tube/flywheel mechanism designed to replicate the gravitational and inertial forces of free weights. Subjects completed each lift with their 10-repetition maximum load. Kinematic data were collected at 250 Hz by a 12-camera motion-capture system (Smart-D, BTS Bioengineering, Milan, Italy), and GRF data were collected at 1000 Hz with independent force platforms for each leg (Model 9261, Kistler Instruments AG, Winterhur, Switzerland). All data were captured simultaneously on a single workstation. The right leg of a single lift for each motion was analyzed. Modeling software (OpenSim 2.2.0, Simbios, Palo Alto, CA) determined joint kinematics and net positive and negative work at each lower extremity joint. Total work was found as the sum of work across all joints and was normalized by system mass. Effect sizes and their 95% confidence intervals were computed between conditions. RESULTS: Peak GRF were similar for each lift. There were no differences between conditions in hip flexion range of motion (ROM). For hip adduction ROM, there were no differences between the NS, WS, and SD. However, hip adduction ROM was greater during the NS and SD than during the ND. Hip rotation ROM was greater during the WS than during the NS and SD, and was greater during the SD than during the ND. For knee and ankle flexion ROM, the ND, WS, and SD were not different, but ROM was greater during the NS than the ND and greater during the WS than the SD. Total eccentric work was greater during the WS than the SD. Otherwise, there were no differences in eccentric or concentric work between conditions. CONCLUSIONS: Although squat and deadlift exercises consist of similar motions, there are kinematic differences between them that depend on stance width. Total eccentric and concentric work are similar for different lifts, but differing kinematics may require activation of different musculature for each variation. With respect to each condition, in the ND the ROM of each joint tended to be less, and the WS tended to trade knee motion for hip motion. PRACTICAL APPLICATIONS: Knowledge of differences in kinematics and kinetics between different squat and deadlift variations is important for coaches and rehabilitation personnel to understand when prescribing exercise. Our results suggest that each variation of the squat and deadlift should be considered a separate exercise that may induce different long-term training effects.

  16. Relative contribution of the pressure variations under the feet and body weight distribution over both legs in the control of upright stance.

    PubMed

    Rougier, P R

    2007-01-01

    The resultant centre of pressure (CP(Res)) trajectories are aimed at controlling body movements in upright stance. When standing on two legs, these trajectories are generated by exerting reaction forces under each foot and by loading-unloading mechanisms intervening at the hip level. To assess the respective contribution of each of these factors in stance maintenance, a group of healthy individuals were tested in several conditions including standing quietly and voluntarily producing under each foot larger CP displacements in phase and in opposite phase along medio-lateral (ML) and antero-posterior (AP) axes. The results, based on the computation of coefficients of correlation between CP(Res) trajectories and various time series including the relative body weight applied to one leg and plantar CP trajectories, highlight some differences according to the axes along which the displacements take place and the amplitudes of the movements. Furthermore, the comparison of the CP(Res) trajectories resulting from each one of these two factors reveals the predominant role played by the loading-unloading mechanisms intervening at the hip level for the movements along the ML axis and those of the plantar CP displacements along the AP axis. Increasing the plantar CP displacements in phase or in opposite phase substantially modifies these contributions although without inferring a shift to the benefit of the other mechanism. The specific morphology of the ankle and hip joints implicated in this postural task plainly explains this postural control organisation. In particular, the link between the segmental configuration of the lower limbs and these mechanisms are discussed. PMID:17196210

  17. Dynamics of quiet human stance: computer simulations of a triple inverted pendulum model.

    PubMed

    Günther, Michael; Wagner, Heiko

    2016-06-01

    For decades, the biomechanical description of quiet human stance has been dominated by the single inverted pendulum (SIP) paradigm. However, in the past few years, the SIP model family has been falsified as an explanatory approach. Double inverted pendulum models have recently proven to be inappropriate. Human topology with three major leg joints suggests in a natural way to examine triple inverted pendulum (TIP) models as an appropriate approach. In this study, we focused on formulating a TIP model that can synthesise stable balancing attractors based on minimalistic sensor information and actuation complexity. The simulated TIP oscillation amplitudes are realistic in vertical direction. Along with the horizontal ankle, knee and hip positions, though, all simulated joint angle amplitudes still exceed the measured ones about threefold. It is likely that they could be eventually brought down to the physiological range by using more sensor information. The TIP systems' eigenfrequency spectra come out as another major result. The eigenfrequencies spread across about [Formula: see text]. Our main result is that joint stiffnesses can be reduced even below statically required values by using an active hip torque balancing strategy. When reducing mono- and bi-articular stiffnesses further down to levels threatening dynamic stability, the spectra indicate a change from torus-like (stable) to strange (chaotic) attractors. Spectra of measured ground reaction forces appear to be strange-attractor-like. We would conclude that TIP models are a suitable starting point to examine more deeply the dynamic character of and the essential structural properties behind quiet human stance. Abbreviations and technical terms Inverted pendulum body exposed to gravity and pivoting in a joint around position of unstable equilibrium (operating point) SIP single inverted pendulum: one rigid body pivoting around fixation to the ground (external joint) DIP double inverted pendulum: two bodies; external and internal joint operate around instability TIP triple inverted pendulum: three bodies; external and both internal joints operate around instability QIP quadruple inverted pendulum: four bodies, foot replaces external joint; all three internal joints operate around instability Eigenfrequency characteristic frequency that a physical system is oscillating at when externally excited at a limited energy level DOF degree of freedom; in mechanics: linear displacement or angle or combination thereof Mono-articular stiffness: coefficient of proportionality between mechanical displacement of a DOF and restoring force/torque component in the respective DOF Bi-articular stiffness coefficient of proportionality between mechanical displacement of a DOF and restoring force/torque component in another DOF GRF ground reaction force HAT segment including head, arms and trunk COM centre of mass COP centre of pressure in the plane of the force platform surface. PMID:26214594

  18. Adopting the ritual stance: The role of opacity and context in ritual and everyday actions.

    PubMed

    Kapitány, Rohan; Nielsen, Mark

    2015-12-01

    Rituals are a pervasive and ubiquitous aspect of human culture, but when we naïvely observe an opaque set of ritual actions, how do we come to understand its significance? To investigate this, across two experiments we manipulated the degree to which actions were ritualistic or ordinary, and whether or not they were accompanied with context. In Experiment 1, 474 adult participants were presented with videos of novel rituals (causally opaque actions) or control actions (causally transparent) performed on a set of objects accompanied with neutral-valance written context. Experiment 2 presented the same video stimuli but with negative and aversive written context. In both experiments ritualized objects were rated as physically unchanged, but more 'special' and more 'desirable' than objects subjected to control actions, with context amplifying this effect. Results are discussed with reference to the Ritual Stance and the Social-Action hypothesis. Implications for both theories are discussed, as are methodological concerns regarding the empirical investigation of ritual cognition. We argue that causally opaque ritual actions guide the behavior of naïve viewers because such actions are perceived as socially normative, rather than with reference to supernatural intervention or causation. PMID:26298423

  19. Enhancing stance phase propulsion during level walking by combining FES with a powered exoskeleton for persons with paraplegia.

    PubMed

    Ha, Kevin H; Quintero, Hugo A; Farris, Ryan J; Goldfarb, Michael

    2012-01-01

    This paper describes the design and implementation of a cooperative controller that combines functional electrical stimulation (FES) with a powered lower limb exoskeleton to provide enhanced hip extension during the stance phase of walking in persons with paraplegia. The controller utilizes two sources of actuation: the electric motors of the powered exoskeleton and the user's machine (FSM), a set of FES. It consists of a finite-state machine (FSM), a set of proportional-derivative (PD) controllers for the exoskeleton and a cycle-to-cycle adaptive controller for muscle stimulation. Level ground walking is conducted on a single subject with complete T10 paraplegia. Results show a 34% reduction in electrical power requirements at the hip joints during the stance phase of the gait cycle with the cooperative controller compared to using electric motors alone. PMID:23365900

  20. The effect of prosthetic feedback on the strategies and synergies used by vestibular loss subjects to control stance

    PubMed Central

    2013-01-01

    Background This study investigated changes in stance movement strategies and muscle synergies when bilateral peripheral vestibular loss (BVL) subjects are provided feedback of pelvis sway angle. Methods Six BVL (all male) and 7 age-matched male healthy control (HC) subjects performed 3 stance tasks: standing feet hip width apart, eyes closed, on a firm and foam surface, and eyes open on foam. Pelvis and upper trunk movements were recorded in the roll and pitch planes. Surface EMG was recorded from pairs of antagonistic muscles at the lower leg, trunk and upper arm. Subjects were first assessed without feedback. Then, they received training with vibrotactile, auditory, and fall-warning visual feedback during stance tasks before being reassessed with feedback. Results Feedback reduced pelvis sway angle displacements to values of HCs for all tasks. Movement strategies were reduced in amplitude but not otherwise changed by feedback. These strategies were not different from those of HCs before or after use of feedback. Low frequency motion was in-phase and high frequency motion anti-phasic. Feedback reduced amplitudes of EMG, activity ratios (synergies) of antagonistic muscle pairs and slightly reduced baseline muscle activity. Conclusions This is the first study demonstrating how vestibular loss subjects achieve a reduction of sway during stance with prosthetic feedback. Unchanged movement strategies with reduced amplitudes are achieved with improved antagonistic muscle synergies. This study suggests that both body movement and muscle measures could be explored when choosing feedback variables, feedback location, and patient groups for prosthetic devices which reduce sway of those with a tendency to fall. PMID:24354579

  1. A dynamic model of the windlass mechanism of the foot: evidence for early stance phase preloading of the plantar aponeurosis.

    PubMed

    Caravaggi, Paolo; Pataky, Todd; Goulermas, John Y; Savage, Russel; Crompton, Robin

    2009-08-01

    In the present study we have estimated the temporal elongation of the plantar aponeurosis (PA) during normal walking using a subject-specific multi-segment rigid-body model of the foot. As previous studies have suggested that muscular forces at the ankle can pre-load the PA prior to heel-strike, the main purpose of the current study was to test, through modelling, whether there is any tension present in the PA during early stance phase. Reflective markers were attached to bony landmarks to track the kinematics of the calcaneus, metatarsus and toes during barefoot walking. Ultrasonography measurements were performed on three subjects to determine both the location of the origin of the PA on the plantar aspect of the calcaneus, and the radii of the metatarsal heads. Starting with the foot in a neutral, unloaded position, inverse kinematics allowed calculation of the tension in the five slips of the PA during the whole duration of the stance phase. The results show that the PA experienced tension significantly above rest during early stance phase in all subjects (P<0.01), thus providing support for the PA-preloading hypothesis. The amount of preloading and the maximum elongation of the slips of the PA decreased from medial to lateral. The mean maximum tension exerted by the PA was 1.5 BW (body weight) over the three subjects. PMID:19617443

  2. Balance in single-limb stance after surgically treated ankle fractures: a 14-month follow-up

    PubMed Central

    Nilsson, Gertrud; Ageberg, Eva; Ekdahl, Charlotte; Eneroth, Magnus

    2006-01-01

    Background The maintenance of postural control is fundamental for different types of physical activity. This can be measured by having subjects stand on one leg on a force plate. Many studies assessing standing balance have previously been carried out in patients with ankle ligament injuries but not in patients with ankle fractures. The aim of this study was to evaluate whether patients operated on because of an ankle fracture had impaired postural control compared to an uninjured age- and gender-matched control group. Methods Fifty-four individuals (patients) operated on because of an ankle fracture were examined 14 months postoperatively. Muscle strength, ankle mobility, and single-limb stance on a force-platform were measured. Average speed of centre of pressure movements and number of movements exceeding 10 mm from the mean value of centre of pressure were registered in the frontal and sagittal planes on a force-platform. Fifty-four age- and gender-matched uninjured individuals (controls) were examined in the single-limb stance test only. The paired Student t-test was used for comparisons between patients' injured and uninjured legs and between side-matched legs within the controls. The independent Student t-test was used for comparisons between patients and controls. The Chi-square test, and when applicable, Fisher's exact test were used for comparisons between groups. Multiple logistic regression was performed to identify factors associated with belonging to the group unable to complete the single-limb stance test on the force-platform. Results Fourteen of the 54 patients (26%) did not manage to complete the single-limb stance test on the force-platform, whereas all controls managed this (p < 0.001). Age over 45 years was the only factor significantly associated with not managing the test. When not adjusted for age, decreased strength in the ankle plantar flexors and dorsiflexors was significantly associated with not managing the test. In the 40 patients who managed to complete the single-limb stance test no differences were found between the results of patients' injured leg and the side-matched leg of the controls regarding average speed and the number of centre of pressure movements. Conclusion One in four patients operated on because of an ankle fracture had impaired postural control compared to an age- and gender-matched control group. Age over 45 years and decreased strength in the ankle plantar flexors and dorsiflexors were found to be associated with decreased balance performance. Further, longitudinal studies are required to evaluate whether muscle and balance training in the rehabilitation phase may improve postural control. PMID:16597332

  3. Recalibration of somesthetic plantar information in the control of undisturbed upright stance maintenance.

    PubMed

    Bernard-Demanze, L; Burdet, C; Berger, L; Rougier, P

    2004-12-01

    To assess the effects of changes in somesthetic plantar information on upright quiet stance, a rotary plantar massage was applied under the feet of healthy subjects for ten minutes. The controlling variable, the centre of pressure (CP) displacements, were recorded, before and after massage, through a force platform and decomposed into two elementary motions: the vertical projection of the centre of gravity (CG(v)) and the difference between the latter and the CP (CP-CG(v)) along medio-lateral ML and antero-posterior AP directions. These motions were processed through frequency analysis and modelled as fractional Brownian motion. For CP-CG(v) motions, the frequency analysis shows that massage under the plantar soles induces a decrease of the amplitudes along the ML direction suggesting reduced overall muscular activity (abductor-adductor muscles of the hip according to Winter et al.). A general trend is that the CG(v) amplitudes are also diminished after massage especially in the ML direction, indicating a better distribution of the body weight on the two supports. On the other hand, the effects tend to vanish after about 8 minutes. Conversely, when the massage was given under the toes, no particular effect on any elementary motion was observed, suggesting that the plantar mechanoreceptors under the toes necessitate stronger stimulation to respond significantly and/or that the greater sensitivity obtained was not used by the CNS. Overall, this data emphasises the fact that a recalibration of somesthetic cues may occur when enhanced afferent information is fed to the postural system. PMID:15657978

  4. Reliability of the Achilles tendon tap reflex evoked during stance using a pendulum hammer.

    PubMed

    Mildren, Robyn L; Zaback, Martin; Adkin, Allan L; Frank, James S; Bent, Leah R

    2016-01-01

    The tendon tap reflex (T-reflex) is often evoked in relaxed muscles to assess spinal reflex circuitry. Factors contributing to reflex excitability are modulated to accommodate specific postural demands. Thus, there is a need to be able to assess this reflex in a state where spinal reflex circuitry is engaged in maintaining posture. The aim of this study was to determine whether a pendulum hammer could provide controlled stimuli to the Achilles tendon and evoke reliable muscle responses during normal stance. A second aim was to establish appropriate stimulus parameters for experimental use. Fifteen healthy young adults stood on a forceplate while taps were applied to the Achilles tendon under conditions in which postural sway was constrained (by providing centre of pressure feedback) or unconstrained (no feedback) from an invariant release angle (50°). Twelve participants repeated this testing approximately six months later. Within one experimental session, tap force and T-reflex amplitude were found to be reliable regardless of whether postural sway was constrained (tap force ICC=0.982; T-reflex ICC=0.979) or unconstrained (tap force ICC=0.968; T-reflex ICC=0.964). T-reflex amplitude was also reliable between experimental sessions (constrained ICC=0.894; unconstrained ICC=0.890). When a T-reflex recruitment curve was constructed, optimal mid-range responses were observed using a 50° release angle. These results demonstrate that reliable Achilles T-reflexes can be evoked in standing participants without the need to constrain posture. The pendulum hammer provides a simple method to allow researchers and clinicians to gather information about reflex circuitry in a state where it is involved in postural control. PMID:26454702

  5. Estimation of Quasi-Stiffness of the Human Hip in the Stance Phase of Walking

    PubMed Central

    Shamaei, Kamran; Sawicki, Gregory S.; Dollar, Aaron M.

    2013-01-01

    This work presents a framework for selection of subject-specific quasi-stiffness of hip orthoses and exoskeletons, and other devices that are intended to emulate the biological performance of this joint during walking. The hip joint exhibits linear moment-angular excursion behavior in both the extension and flexion stages of the resilient loading-unloading phase that consists of terminal stance and initial swing phases. Here, we establish statistical models that can closely estimate the slope of linear fits to the moment-angle graph of the hip in this phase, termed as the quasi-stiffness of the hip. Employing an inverse dynamics analysis, we identify a series of parameters that can capture the nearly linear hip quasi-stiffnesses in the resilient loading phase. We then employ regression analysis on experimental moment-angle data of 216 gait trials across 26 human adults walking over a wide range of gait speeds (0.75–2.63 m/s) to obtain a set of general-form statistical models that estimate the hip quasi-stiffnesses using body weight and height, gait speed, and hip excursion. We show that the general-form models can closely estimate the hip quasi-stiffness in the extension (R2 = 92%) and flexion portions (R2 = 89%) of the resilient loading phase of the gait. We further simplify the general-form models and present a set of stature-based models that can estimate the hip quasi-stiffness for the preferred gait speed using only body weight and height with an average error of 27% for the extension stage and 37% for the flexion stage. PMID:24349136

  6. Lateral orientation and stabilization of human stance: static versus dynamic visual cues.

    PubMed

    Amblard, B; Crémieux, J; Marchand, A R; Carblanc, A

    1985-01-01

    The differential contributions of static versus dynamic visual cues to postural control were studied in human subjects. Lateral body oscillations were measured with accelerometers located at head, hips and ankle levels, while subjects righted their balance under various mechanical conditions: on either a soft (foam rubber) support or a hard one, and in either the classical or the sharpened Romberg stance. The visual pattern (horizontal or vertical rectangular grating) was illuminated with either a stroboscopic bulb or a normal one, and control measurements were also taken in darkness for each mechanical condition. Acceleration signals were processed into their frequency power spectra, the mean area and shape of which were taken to characterize the postural skills involved and the effects of either the visual suppressions or the mechanical destabilizations. Although dynamic visual cues have already been found to play a major role in the control of lateral body sway (Amblard and Crémieux 1976), we demonstrate here that static visual cues, the only ones available under stroboscopic illumination, also make a clear though minor contribution. Hence we suggest the existence of two modes of visual control of lateral balance in man, which are well separated in terms of the frequency range of body sway: the first mechanism, which operates below 2 Hz and is strobe-resistant, seems to control the orientation of the upper part of the body; the second mechanism, which operates above 4 Hz, centers on about 7 Hz and is strobe-vulnerable, seems to immobilize the body working upwards from the feet. Thus static visual cues may slowly control re-orientation or displacement, whereas dynamic visual cues may contribute to fast stabilization of the body. In between the frequency ranges at which these two visuomotor mechanisms come into play, at about 3 Hz, there is what we call a "blind frequency", a visually neutral sway frequency which may arise from the incompatibility of visual reorientation with visual stabilization, and where vision appears unable to reduce postural sway to any marked extent. Transmission of the destabilization produced by suppression of visual cues or by mechanical methods from one anatomical level to another is also briefly discussed in terms of bio-mechanical constraints, and the correlations between various pairs of levels are considered. PMID:4085597

  7. Using Argument-Driven Inquiry to enhance students' argument sophistication when supporting a stance in the context of Socioscientific Issues

    NASA Astrophysics Data System (ADS)

    Grooms, Jonathon A.

    This quasi-experimental study assesses the extent to which the Argument-Driven Inquiry (ADI) instructional model enhances undergraduate students' abilities to generate quality arguments supporting their stance in the context of a Socioscientific Issue (SSI) as compared to students experiencing a traditional style of instruction. Enhancing the quality of undergraduate students' arguments in the context of SSI can serve as an indirect measure of their scientific literacy and their ability to make sound decisions on issues that are inherently scientific but also involve social implications. Data collected in this study suggest that the undergraduate students experiencing the ADI instruction more readily provide rationales in their arguments supporting their decisions regarding two SSI-tasks as compared to a group of undergraduate students experiencing traditional instruction. This improvement in argument quality and gain in scientific literacy was achieved despite the overall lower SSI related content knowledge of the ADI students. Furthermore, the gap between the argument quality of those students with high versus low SSI related content knowledge was closed within the ADI group, while the same gap persisted post-intervention within the traditional instruction students. The role of students' epistemological sophistication was also investigated, which showed that neither instructional strategy was effective at shifting students' epistemological sophistication toward an evaluativist stance. However, the multiplists within the ADI group were able to significantly increase the sophistication of their arguments whereas the traditional students were not. There were no differences between the quality of arguments generated by the evaluativist students with either the treatment or comparison groups. Finally, the nature of the justifications used by the students revealed that the students (both comparison and treatment groups) did not invoke science-based justifications when supporting their stance, despite students' self-reports that scientific content knowledge accounted for the greatest influence on their stance, related to the SSI tasks. The results of this study suggest that the scientific habits of mind the students learned in the context of ADI investigations are transferred to the novel SSI contexts. Implications for the use of argument-based instructional models to enhance the generation of socioscientific arguments and to promote the development of scientific literacy are also discussed.

  8. Force-sensitive afferents recruited during stance encode sensory depression in the contralateral swinging limb during locomotion

    PubMed Central

    Hochman, Shawn; Hayes, Heather Brant; Speigel, Iris; Chang, Young-Hui

    2013-01-01

    Afferent feedback alters muscle activity during locomotion and must be tightly controlled. As primary afferent depolarization-induced presynaptic inhibition (PAD-PSI) regulates afferent signaling, we investigated hind limb PAD-PSI during locomotion in an in vitro rat spinal cord-hind limb preparation. We compared the relation of PAD-PSI, measured as dorsal root potentials (DRPs), to observed ipsilateral and contralateral limb endpoint forces. Afferents activated during stance-phase force strongly and proportionately influenced DRP magnitude in the swinging limb. Responses increased with locomotor frequency. Electrical stimulation of contralateral afferents also preferentially evoked DRPs in the opposite limb during swing (flexion). Nerve lesioning in conjunction with kinematic results support a prominent contribution from toe Golgi tendon organ afferents. Thus, force-dependent afferent feedback during stance binds interlimb sensorimotor state to a proportional PAD-PSI in the swinging limb, presumably to optimize interlimb coordination. These results complement known actions of ipsilateral afferents on PAD-PSI during locomotion. PMID:23531008

  9. Gait modification strategies of trunk over left stance phase in patients with right anterior cruciate ligament deficiency

    PubMed Central

    Shi, Dongliang; Li, Nannan; Wang, Yubin; Jiang, Shuyun; Li, Jinglong; Zhu, Wenhui

    2015-01-01

    Purpose: To investigate the gait modification strategies of trunk over left stance phase in patients with right anterior cruciate ligament deficiency (ACL-D). Methods: Thirty-six patients with right ACL-D and thirty-six health subjects (control) were recruited to undergo a 3-dimensional (3D) gait analysis. Coordinate data from 26 reflective markers positioned on the body surface of participants were recorded with a 3D optical video motion capture system, as they walked on the ground, ascended and descended a custom-built staircase. Angle changes in the 3-planes under different walking conditions were analyzed. Results: There were statistically significant differences between the two groups in the trunk at the transverse plane angle in most measurements. With the walk pattern of stair descent, the trunk at all 3-plane angles, at the maximum value of the left knee sagittal/coronal/transverse plane moment, was significantly different between the two groups (P ≤ 0.03). Conclusions: Our findings suggested that special gait modification of trunk is apparent over stance of left (healthy) side in patients with right ACL-D. The results of this study may supply more insight with respect to improving the diagnosis and rehabilitation of ACL-D. This information may also be helpful for a better use of walk and stair tasks as part of a rehabilitation program and provide a safe guideline for the patients. PMID:26550279

  10. Altered postural modulation of Hoffmann reflex in the soleus and fibularis longus associated with chronic ankle instability.

    PubMed

    Kim, Kyung-Min; Ingersoll, Christopher D; Hertel, Jay

    2012-12-01

    Our purpose was to assess Hoffmann (H) reflex modulations of the soleus and fibularis longus in three body positions (prone, bipedal and unipedal stances) in subjects with and without chronic ankle instability (CAI). Sixteen subjects with unilateral CAI and 15 healthy controls participated. Maximum H-reflexes and motor (M) waves were recorded bilaterally from the soleus and fibularis longus while subjects lied prone and then stood in quiet bipedal and unipedal stances. Maximum H-reflexes were normalized to maximum M waves to obtain H(max):M(max) ratios for the three positions. H-reflex modulations, for each muscle, were quantified as the percent change scores in H(max):M(max) ratios between each pair of positions: prone to bipedal, bipedal to unipedal, and prone to unipedal. There were significant group by limb interactions found for all three modulations (P < 0.05) for the soleus. In the CAI group, soleus modulations in involved limbs were significantly lower than in uninvolved limbs and both limbs in the controls. For the fibularis longus, similar results were found for the bipedal to unipedal and prone to unipedal modulations. Constrained ability of the sensorimotor system to down regulate H-reflex in more demanding postures may represent a potential mechanism of postural control deficits associated with CAI. PMID:22795679

  11. Restoration of Stance Phase Knee Flexion during Walking after Spinal Cord Injury using a Variable Impedance Orthosis

    PubMed Central

    Bulea, Thomas C.; Kobetic, Rudi; Triolo, Ronald. J.

    2013-01-01

    A hybrid neuroprosthesis (HNP) combines lower extremity bracing with functional neuromuscular stimulation (FNS) to restore walking function and enhance the efficiency of ambulation. This report details the development of a novel HNP containing a variable impedance knee mechanism (VIKM) capable of supporting the knee against collapse while allowing controlled stance phase knee flexion. The design of a closed loop, finite state controller for coordination of VIKM activity with FNS-driven gait is presented. The controller is verified in testing during able bodied gait. The improved functionality provided by this system has the potential to delay the onset of fatigue and to expand FNS driven gait to allow walking over uneven terrains and down stairs. PMID:22254383

  12. Gait modification strategies in trunk over right stance phase in patients with right anterior cruciate ligament deficiency.

    PubMed

    Shi, Dongliang; Li, Nannan; Wang, Yubin; Jiang, Shuyun; Lin, Jianping; Zhu, Wenhui

    2016-05-01

    This study aimed to investigate the gait modification strategies of trunk over right stance phase in patients with right anterior cruciate ligament deficiency (ACL-D). Thirty-six patients with right chronic ACL-D were recruited, as well as 36 controls. A 3D optical video motion capture system was used during gait and stair ambulation. Kinematic variables of the trunk and kinematic and kinetic variables of the knee were calculated. Patients with chronic right ACL-D exhibited many significant abnormalities compared with controls. Trunk rotation with right shoulder trailing over the right stance phase was lower in all five motion patterns (P<0.05). Compared with controls, trunk posterior lean was higher from descending stairs to walking when the knee sagittal plane moment ended (P<0.01). Trunk lateral flexion to the left was higher when ascending stairs at the start of right knee coronal plane moment (P=0.01), when descending stairs at the maximal knee coronal plane moment (P<0.01), and when descending stairs at the end of the knee coronal plane moment (P=0.03). Trunk rotation with right shoulder forward was higher at the minimal knee transverse plane moment (P<0.01) and when the knee transverse plane moment ended (P<0.01); during walking, trunk rotation with right shoulder trailing was lower at other knee moments during other walking patterns (all P<0.01). In conclusion, gait modification strategies of the trunk were apparent in patients with ACL-D. These results provide new insights about diagnosis and rehabilitation of chronic ACL-D (better use of walking and stair tasks as part of a rehabilitation program). PMID:27131179

  13. Talk and Conceptual Change at Work: Adequate Representation and Epistemic Stance in a Comparative Analysis of Statistical Consulting and Teacher Workgroups

    ERIC Educational Resources Information Center

    Hall, Rogers; Horn, Ilana Seidel

    2012-01-01

    In this article we ask how concepts that organize work in two professional disciplines change during moments of consultation, which represent concerted efforts by participants to work differently now and in the future. Our analysis compares structures of talk, the adequacy of representations of practice, and epistemic and moral stances deployed…

  14. Origins of Children's Externalizing Behavior Problems in Low-Income Families: Toddlers’ Willing Stance toward their Mothers as the Missing Link

    PubMed Central

    Kochanska, Grazyna; Kim, Sanghag; Boldt, Lea J.

    2013-01-01

    Although children's active role in socialization has been long acknowledged, relevant research has typically focused on children's difficult temperament or negative behaviors that elicit coercive and adversarial processes, largely overlooking their capacity to act as positive, willing, even enthusiastic, active socialization agents. We studied the willing, receptive stance toward their mothers in 186 24-44-month-old children in a low-income sample. Confirmatory Factor Analysis supported a latent construct of willing stance, manifested as children's responsiveness to mothers in naturalistic interactions, responsive imitation in teaching contexts, and committed compliance with maternal prohibitions, all observed in the laboratory. Structural Equation Modeling analyses confirmed that ecological adversity undermined maternal responsiveness and responsiveness, in turn, was linked to children's willing stance. A compromised willing stance predicted externalizing behavior problems, assessed 10 months later, and fully mediated the links between maternal responsiveness and those outcomes. Ecological adversity had a direct, unmediated effect on internalizing behavior problems. Considering children's active role as willing, receptive agents capable of embracing parental influence can lead to a more complete understanding of detrimental mechanisms that link ecological adversity with antisocial developmental pathways. It can also inform research on the normative socialization process, consistent with the objectives of developmental psychopathology. PMID:24229537

  15. Taking an Effective Authorial Stance in Academic Writing: Making the Linguistic Resources Explicit for L2 Writers in the Social Sciences

    ERIC Educational Resources Information Center

    Chang, Peichin; Schleppegrell, Mary

    2011-01-01

    Taking an assertive stance toward research being reviewed or reported is a challenging task for second language writers. This aspect of interpersonal meaning is especially difficult to address through direct instruction, as attention to particular grammatical and lexical choices outside of contexts of use is not enough to help students develop the…

  16. "How Do I Do It if I Don't Like Writing?": Adolescents' Stances toward Writing across Disciplines

    ERIC Educational Resources Information Center

    Jeffery, Jill V.; Wilcox, Kristen

    2014-01-01

    This research embedded in the National Study of Writing Instruction examines higher- and lower-achieving adolescents' stances toward content-area writing through a qualitative discourse analysis of interviews with 40 students in California, Kentucky, New York, and Texas secondary schools. The study asked: (1) How do students' stances…

  17. Time

    ERIC Educational Resources Information Center

    Circle, David

    2005-01-01

    When a teacher gives their time to a student, it is more significant to that student than anything else one could do for him or her. Music teachers deal with time all the time. Someone once said that "time is like money: we never have enough." This may seem true; however, time is not like money. One can make more money, but one cannot "make time."…

  18. The influence of visual information on multi-muscle control during quiet stance: a spectral analysis approach.

    PubMed

    Danna-Dos-Santos, Alessander; Degani, Adriana M; Boonstra, Tjeerd W; Mochizuki, Luis; Harney, Allison M; Schmeckpeper, Megan M; Tabor, Lori C; Leonard, Charles T

    2015-02-01

    Standing upright requires the coordination of neural drives to a large set of muscles involved in controlling human bipedal stance (i.e., postural muscles). The coordination may deteriorate in situations where standing is performed under more challenging circumstances, such as standing on a smaller base of support or not having adequate visual information. The present study investigates the role of common neural inputs in the organization of multi-muscle synergies and the effects of visual input disruption to this mechanism of control. We analyzed the strength and distribution of correlated neural inputs (measured by intermuscular coherence) to six postural muscles previously recognized as components of synergistic groups involved in the maintenance of the body's vertical positioning. Two experimental conditions were studied: quiet bipedal stance performed with opened eyes (OEs) and closed eyes (CEs). Nine participants stood quietly for 30 s while the activity of the soleus, biceps femoris, lumbar erector spinae, tibialis anterior, rectus femoris, and rectus abdominis muscles were recorded using surface electrodes. Intermuscular (EMG-EMG) coherence was estimated for 12 muscle pairs formed by these muscles, including pairs formed solely by either posterior, anterior, or mixed (one posterior and one anterior) muscles. Intermuscular coherence was only found to be significant for muscle pairs formed solely by either posterior or anterior muscles, and no significant coherence was found for mixed muscle pairs. Significant intermuscular coherence was only found within a distinct frequency interval bounded between 1 and 10 Hz when visual input was available (OEs trials). The strength of correlated neural inputs was similar across muscle pairs located in different joints but executing a similar function (pushing body either backward or forward) suggesting that synergistic postural groups are likely formed based on their functional role instead of their anatomical location. Absence of visual information caused a significant decrease in intermuscular coherence. These findings are consistent with the hypothesis that correlated neural inputs are a mechanism used by the CNS to assemble synergistic muscle groups. Further, this mechanism is affected by interruption of visual input. PMID:25407521

  19. Evaluative Decision-Making for High-Quality Professional Development: Cultivating an Evaluative Stance

    ERIC Educational Resources Information Center

    Sumsion, Jennifer; Lunn Brownlee, Joanne; Ryan, Sharon; Walsh, Kerryann; Farrell, Ann; Irvine, Susan; Mulhearn, Gerry; Berthelsen, Donna

    2015-01-01

    Unprecedented policy attention to early childhood education internationally has highlighted the crucial need for a skilled early years workforce. Consequently, professional development of early years educators has become a global policy imperative. At the same time, many maintain that professional development research has reached an impasse. In…

  20. Therapeutic Experience on Stance Control Knee-Ankle-Foot Orthosis With Electromagnetically Controlled Knee Joint System in Poliomyelitis

    PubMed Central

    Kim, Jung-Hwan; Ji, Sang-Goo; Jung, Kang-Jae

    2016-01-01

    A 54-year-old man with poliomyelitis had been using a conventional, passive knee-ankle-foot orthosis (KAFO) with a drop ring lock knee joint for about 40 years. A stance control KAFO (SCKAFO) with an electromagnetically controlled (E-MAG) knee joint system was prescribed. To correct his gait pattern, he also underwent rehabilitation therapy, which included muscle re-education, neuromuscular electrical stimulation, strengthening exercises for the lower extremities, and balance training twice a week for about 4 months. Both before and after rehabilitation, we conducted a gait analysis and assessed the physiological cost index in energy expended during walking in a locked-knee state and while he wore a SCKAFO with E-MAG. When compared with the pre-rehabilitation data, the velocity, step length, stride length, and knee kinematic data were improved after rehabilitation. Although the SCKAFO with E-MAG system facilitated the control of knee motion during ambulation, appropriate rehabilitative therapy was also needed to achieve a normal gait pattern. PMID:27152288

  1. Therapeutic Experience on Stance Control Knee-Ankle-Foot Orthosis With Electromagnetically Controlled Knee Joint System in Poliomyelitis.

    PubMed

    Kim, Jung-Hwan; Ji, Sang-Goo; Jung, Kang-Jae; Kim, Jae-Hyung

    2016-04-01

    A 54-year-old man with poliomyelitis had been using a conventional, passive knee-ankle-foot orthosis (KAFO) with a drop ring lock knee joint for about 40 years. A stance control KAFO (SCKAFO) with an electromagnetically controlled (E-MAG) knee joint system was prescribed. To correct his gait pattern, he also underwent rehabilitation therapy, which included muscle re-education, neuromuscular electrical stimulation, strengthening exercises for the lower extremities, and balance training twice a week for about 4 months. Both before and after rehabilitation, we conducted a gait analysis and assessed the physiological cost index in energy expended during walking in a locked-knee state and while he wore a SCKAFO with E-MAG. When compared with the pre-rehabilitation data, the velocity, step length, stride length, and knee kinematic data were improved after rehabilitation. Although the SCKAFO with E-MAG system facilitated the control of knee motion during ambulation, appropriate rehabilitative therapy was also needed to achieve a normal gait pattern. PMID:27152288

  2. Activation of the gluteus medius according to load during horizontal hip abduction in a one-leg stance

    PubMed Central

    Lee, Jae-Woong; Kim, Yeong-Ju; Koo, Hyun-Mo

    2015-01-01

    [Purpose] This study researched the influences of different loads on muscle activity of the posterior fibers of the gluteus medius in a one-leg standing position. [Subjects] Twenty-four healthy adult men participated in this study. [Methods] All participants performed the one-leg standing position under four conditions: the standard no-load condition, in which the non-weight-bearing leg was lifted and kept parallel to the back and then pelvic or lumbar rotation was performed without thorax rotation, and the 0 kg, 1 kg, and 3 kg load conditions, in which horizontal shoulder abduction was performed with a load of 0 kg, 1 kg, or 3 kg added to the hand. The electromyographic activity of the posterior fibers of the gluteus medius was measured using a wireless surface electromyography under all conditions. The electromyographic activity of each muscle under the four conditions during the one-leg stance was analyzed using one-way analysis of variance. [Results] The electromyographic activity of the posterior fiber of the gluteus medius was significantly increased under the 3 kg load condition compared with the no-load, 0 kg load, and 1 kg load conditions. [Conclusion] These findings indicated that muscle activation is affected by increases in load in the one-leg standing position. The load on the upper extremity influences the muscle activity of the contralateral lower extremity. PMID:26356544

  3. The effects of dual-channel functional electrical stimulation on stance phase sagittal kinematics in patients with hemiparesis.

    PubMed

    Springer, Shmuel; Vatine, Jean-Jacques; Wolf, Alon; Laufer, Yocheved

    2013-04-01

    Sixteen subjects (aged 54.2 ± 14.1 years) with hemiparesis (7.9 ± 7.1 years since diagnosis) demonstrating a foot-drop and hamstrings muscle weakness were fitted with a dual-channel functional electrical stimulation (FES) system activating the dorsiflexors and hamstrings muscles. Measurements of gait performance were collected after a conditioning period of 6 weeks, during which the subjects used the system throughout the day. Gait was assessed with and without the dual-channel FES system, as well as with peroneal stimulation alone. Outcomes included lower limb kinematics and the step length taken with the non-paretic leg. Results with the dual-channel FES indicate that in the subgroup of subjects who demonstrated reduced hip extension but no knee hyperextension (n = 9), hamstrings FES increased hip extension during terminal stance without affecting the knee. Similarly, in the subgroup of subjects who demonstrated knee hyperextension but no limitation in hip extension (n = 7), FES restrained knee hyperextension without having an impact on hip movement. Additionally, step length was increased in all subjects. The peroneal FES had a positive effect only on the ankle. The results suggest that dual-channel FES for the dorsiflexors and hamstrings muscles may affect lower limb control beyond that which can be attributed to peroneal stimulation alone. PMID:23231828

  4. Time?

    NASA Astrophysics Data System (ADS)

    Amoroso, Richard L.

    2013-09-01

    The concept of time in the `clockwork' Newtonian world was irrelevant; and has generally been ignored until recently by several generations of physicists since the implementation of quantum mechanics. We will set aside the utility of time as a property relating to physical calculations of events relating to a metrics line element or as an aspect of the transformation of a particles motion/interaction in a coordinate system or in relation to thermodynamics etc., i.e. we will discard all the usual uses of time as a concept used to circularly define physical parameters in terms of other physical parameters; concentrating instead on time as an aspect of the fundamental cosmic topology of our virtual reality especially as it inseparably relates to the nature and role of the observer in natural science.

  5. Clarification of functional differences between the hallux and lesser toes during the single leg stance: immediate effects of conditioning contraction of the toe plantar flexion muscles

    PubMed Central

    Saeki, Junya; Tojima, Michio; Torii, Suguru

    2015-01-01

    [Purpose] The purpose of this study was to determine the functional differences of the plantar flexion muscles of the hallux and lesser toes during the single leg stance by comparing postural sway in different conditioning contraction interventions. [Subjects] Thirty-four healthy, young males and females participated in this study. [Methods] The front-back and right-left direction components of maximal displacement and postural sway velocity during the single leg stance were measured in various conditioning contraction interventions for the plantar flexion muscles of the hallux or lessor toes. [Results] The main findings of this study were as follows: 1) the front-back direction component of maximal displacement was reduced by conditioning contraction of the plantar flexion muscles of the hallux, and 2) the front-back direction component of the postural sway velocity was reduced by conditioning contraction of the plantar flexion muscles of the lesser toes during the single leg stance. [Conclusion] The plantar flexion muscles of the lesser toes control the postural sway velocity. Furthermore, the plantar flexion muscles of the hallux appear to control the amplitude of postural sway. PMID:26504272

  6. (Positive) Power to the Child: The Role of Children's Willing Stance toward Parents in Developmental Cascades from Toddler Age to Early Preadolescence

    PubMed Central

    Kochanska, Grazyna; Kim, Sanghag; Boldt, Lea J.

    2015-01-01

    In contrast to once dominant views of children as passive in the parent-led process of socialization, they are now seen as active agents who can considerably influence that process. But those newer perspectives typically focus on the child's antagonistic influence, due either to a difficult temperament or aversive, resistant, negative behaviors that elicit adversarial responses from the parent and lead to future coercive cascades in the relationship. Children's capacity to act as receptive, willing, even enthusiastic, active socialization agents is largely overlooked. Informed by attachment theory and other relational perspectives, we depict children as able to adopt an active willing stance and to exert robust positive influence in the mutually cooperative socialization enterprise. A longitudinal study of 100 community families (mothers, fathers, and children) demonstrates that willing stance (a) is a latent construct, observable in diverse parent-child contexts parallel at 38, 52, and 67 months, and longitudinally stable, (b) originates within an early secure parent-child relationship at 25 months, and (c) promotes a positive future cascade toward adaptive outcomes at age 10. The outcomes include the parent's observed and child-reported positive, responsive behavior, as well as child-reported internal obligation to obey the parent and parent-reported low level of child behavior problems. The construct of willing stance has implications for basic research in typical socialization and in developmental psychopathology, and for prevention and intervention. PMID:26439058

  7. (Positive) power to the child: The role of children's willing stance toward parents in developmental cascades from toddler age to early preadolescence.

    PubMed

    Kochanska, Grazyna; Kim, Sanghag; Boldt, Lea J

    2015-11-01

    In a change from the once-dominant view of children as passive in the parent-led process of socialization, children are now seen as active agents who can considerably influence that process. However, these newer perspectives typically focus on the child's antagonistic influence, due either to a difficult temperament or aversive, resistant, negative behaviors that elicit adversarial responses from the parent and lead to future coercive cascades in the relationship. Children's capacity to act as receptive, willing, even enthusiastic, active socialization agents is largely overlooked. Informed by attachment theory and other relational perspectives, we depict children as able to adopt an active willing stance and to exert robust positive influence in the mutually cooperative socialization enterprise. A longitudinal study of 100 community families (mothers, fathers, and children) demonstrates that willing stance (a) is a latent construct, observable in diverse parent-child contexts, parallel at 38, 52, and 67 months and longitudinally stable; (b) originates within an early secure parent-child relationship at 25 months; and (c) promotes a positive future cascade toward adaptive outcomes at age 10. The outcomes include the parent's observed and child-reported positive, responsive behavior, as well as child-reported internal obligation to obey the parent and parent-reported low level of child behavior problems. The construct of willing stance has implications for basic research in typical socialization and in developmental psychopathology as well as for prevention and intervention. PMID:26439058

  8. Effect of using poles on foot-ground kinetics during stance phase in trail running.

    PubMed

    Daviaux, Yannick; Hintzy, Frédérique; Samozino, Pierre; Horvais, Nicolas

    2013-01-01

    The aim of this study was to investigate the effect of using poles on foot-ground interaction during trail running with slopes of varying incline. Ten runners ran on a loop track representative of a trail running field situation with uphill (+9°), level and downhill (-6°) sections at fixed speed (3.2 m.s(-1)). Experimental conditions included running with (WP) and without (NP) the use of poles for each of the three slopes. Several quantitative and temporal foot-ground interaction parameters were calculated from plantar pressure data measured with a portable device. Using poles induced a decrease in plantar pressure intensity even when the running velocity stayed constant. However, the localisation and the magnitude of this decrease depended on the slope situations. During WP level running, regional analysis of the foot highlighted a decrease of the force time integral (FTI) for absolute (FTIabs; -12.6%; P<0.05) and relative values (FTIrel; -14.3%; P<0.05) in the medial forefoot region. FTIabs (-14.2%; P<0.05) and duration of force application (Δt; -13.5%; P<0.05) also decreased in the medial heel region when WP downhill running. These results support a facilitating effect of pole use for propulsion during level running and for the absorption phase during downhill running. PMID:24050463

  9. US definitions, current use, and FDA stance on use of platelet-rich plasma in sports medicine.

    PubMed

    Beitzel, Knut; Allen, Donald; Apostolakos, John; Russell, Ryan P; McCarthy, Mary Beth; Gallo, Gregory J; Cote, Mark P; Mazzocca, Augustus D

    2015-02-01

    With increased utilization of platelet-rich plasma (PRP), it is important for clinicians to understand the United States, the Food and Drug Administration (FDA) regulatory role and stance on PRP. Blood products such as PRP fall under the prevue of FDA's Center for Biologics Evaluation and Research (CBER). CBER is responsible for regulating human cells, tissues, and cellular and tissue-based products. The regulatory process for these products is described in the FDA's 21 CFR 1271 of the Code of Regulations. Under these regulations, certain products including blood products such as PRP are exempt and therefore do not follow the FDA's traditional regulatory pathway that includes animal studies and clinical trials. The 510(k) application is the pathway used to bring PRP preparation systems to the market. The 510(k) application allows devices that are "substantially equivalent" to a currently marketed device to come to the market. There are numerous PRP preparation systems on the market today with FDA clearance; however, nearly all of these systems have 510(k) clearance for producing platelet-rich preparations intended to be used to mix with bone graft materials to enhance bone graft handling properties in orthopedic practices. The use of PRP outside this setting, for example, an office injection, would be considered "off label." Clinicians are free to use a product off-label as long as certain responsibilities are met. Per CBER, when the intent is the practice of medicine, clinicians "have the responsibility to be well informed about the product, to base its use on firm scientific rationale and on sound medical evidence, and to maintain records of the product's use and effects." Finally, despite PRP being exempted, the language in 21 CFR 1271 has caused some recent concern over activated PRP; however to date, the FDA has not attempted to regulate activated PRP. Clinicians using activated PRP should be mindful of these concerns and continued to stay informed. PMID:25268794

  10. Age-related influence of vision and proprioception on Ia presynaptic inhibition in soleus muscle during upright stance.

    PubMed

    Baudry, Stphane; Duchateau, Jacques

    2012-11-01

    This study investigated the modulation of Ia afferent input in young and elderly adults during quiet upright stance in normal and modified visual and proprioceptive conditions. The surface EMG of leg muscles, recruitment curve of the soleus (SOL) Hoffmann (H) reflex and presynaptic inhibition of Ia afferents from SOL, assessed with the D1 inhibition and single motor unit methods, were recorded when young and elderly adults stood with eyes open or closed on two surfaces (rigid vs. foam) placed over a force platform. The results showed that elderly adults had a longer path length for the centre of pressure and larger antero-posterior body sway across balance conditions (P < 0.05). Muscle EMG activities were greater in elderly compared with young adults (P < 0.05), whereas the H(max) expressed as a percentage of the H(max) was lower (P = 0.048) in elderly (38 16%) than young adults (58 16%). The conditioned H reflex/test H reflex ratio (D1 inhibition method) increased with eye closure and when standing on foam (P < 0.05), with greater increases for elderly adults (P = 0.019). These changes were accompanied by a reduced peak motor unit discharge probability when standing on rigid and foam surfaces (P 0.001), with a greater effect for elderly adults (P = 0.026). Based on these latter results, the increased conditioned H reflex/test H reflex ratio in similar sensory conditions is likely to reflect occlusion at the level of presynaptic inhibitory interneurones. Together, these findings indicate that elderly adults exhibit greater modulation of Ia presynaptic inhibition than young adults with variation in the sensory conditions during upright standing. PMID:22946095

  11. Naturalness as an ethical stance: idea(l)s and practices of care in western herbal medicine in the UK.

    PubMed

    Nissen, Nina

    2015-01-01

    An association of non-biomedical healthcare with appeals to nature and naturalness, and an invocation of a rhetoric of gentleness, goodness, purity and moral power has been noted previously, and some scholars argue that nature has taken on a meaning broadly opposed to the rational scientific order of modernity. Drawing on an ethnographic study of women's practice and use of western herbal medicine (WHM) in the UK, the intertwining of the perceived naturalness of WHM with distinct care practices points to a further avenue for exploration. To examine patients' and herbalists' discourses of the naturalness of WHM and associated idea(l)s and practices of care, understandings of nature and a feminist ethics of care are utilized as analytical frameworks. The analysis presented suggests that, through WHM, patients and herbalists become embedded in a complex spatio-temporal wholeness and web of care that intertwines past, present and future, self and others, and local and global concerns. In the emerging 'ordinary ethics of care', naturalness constitutes a sign of goodness and of a shared humanity within the organic world, while care, underpinned by idea(l)s of natural and holistic care practices, links human and non-human others. Thus, the naturalness of WHM, as perceived by some patients and herbalists, engages and blends with a continually unfolding field of relationships in the lifeworld(s), where care practices, caring relations and collective wellbeing may constitute an ethical stance that raises deeper questions about the significance of relationality, the values of care/caring and the mutual involvement of nature and human being(s). PMID:26001272

  12. Estimation of Quasi-Stiffness and Propulsive Work of the Human Ankle in the Stance Phase of Walking

    PubMed Central

    Shamaei, Kamran; Sawicki, Gregory S.; Dollar, Aaron M.

    2013-01-01

    Characterizing the quasi-stiffness and work of lower extremity joints is critical for evaluating human locomotion and designing assistive devices such as prostheses and orthoses intended to emulate the biological behavior of human legs. This work aims to establish statistical models that allow us to predict the ankle quasi-stiffness and net mechanical work for adults walking on level ground. During the stance phase of walking, the ankle joint propels the body through three distinctive phases of nearly constant stiffness known as the quasi-stiffness of each phase. Using a generic equation for the ankle moment obtained through an inverse dynamics analysis, we identify key independent parameters needed to predict ankle quasi-stiffness and propulsive work and also the functional form of each correlation. These parameters include gait speed, ankle excursion, and subject height and weight. Based on the identified form of the correlation and key variables, we applied linear regression on experimental walking data for 216 gait trials across 26 subjects (speeds from 0.75–2.63 m/s) to obtain statistical models of varying complexity. The most general forms of the statistical models include all the key parameters and have an R2 of 75% to 81% in the prediction of the ankle quasi-stiffnesses and propulsive work. The most specific models include only subject height and weight and could predict the ankle quasi-stiffnesses and work for optimal walking speed with average error of 13% to 30%. We discuss how these models provide a useful framework and foundation for designing subject- and gait-specific prosthetic and exoskeletal devices designed to emulate biological ankle function during level ground walking. PMID:23555839

  13. Influence of Electrotactile Tongue Feedback on Controlling Upright Stance during Rotational and/or Translational Sway-referencing with Galvanic Vestibular Stimulation

    NASA Technical Reports Server (NTRS)

    Wood, Scott J.; Tyler, Mitchell E.; Bach-y-Rita, Paul; MacDougall, Hamish G.; Moore, Steven T.; Stallings, Valerie L.; Paloski, William H.; Black, F. Owen

    2007-01-01

    Integration of multi-sensory inputs to detect tilts relative to gravity is critical for sensorimotor control of upright orientation. Displaying body orientation using electrotactile feedback to the tongue has been developed by Bach-y-Rita and colleagues as a sensory aid to maintain upright stance with impaired vestibular feedback. MacDougall et al. (2006) recently demonstrated that unpredictably varying Galvanic vestibular stimulation (GVS) significantly increased anterior-posterior (AP) sway during rotational sway referencing with eyes closed. The purpose of this study was to assess the influence of electrotactile feedback on postural control performance with pseudorandom binaural bipolar GVS. Postural equilibrium was measured with a computerized hydraulic platform in 10 healthy adults (6M, 4F, 24-65 y). Tactile feedback (TF) of pitch and roll body orientation was derived from a two-axis linear accelerometer mounted on a torso belt and displayed on a 144-point electrotactile array held against the anterior dorsal tongue (BrainPort, Wicab, Inc., Middleton, WI). Subjects were trained to use TF by voluntarily swaying to draw figures on their tongue, both with and without GVS. Subjects were required to keep the intraoral display in their mouths on all trials, including those that did not provide TF. Subjects performed 24 randomized trials (20 s duration with eyes closed) including four support surface conditions (fixed, rotational sway-referenced, translating the support surface proportional to AP sway, and combined rotational-translational sway-referencing), each repeated twice with and without GVS, and with combined GVS and TF. Postural performance was assessed using deviations from upright (peak-to-peak and RMS sway) and convergence toward stability limits (time and distance to base of support boundaries). Postural stability was impaired with GVS in all platform conditions, with larger decrements in performance during trials with rotation sway-referencing. Electrotactile feedback improved performance with GVS toward non-GVS levels, again with the greatest improvement during trials with rotation sway-referencing. These results demonstrate the effectiveness of tongue electrotactile feedback in providing sensory substitution to maintain postural stability with distorted vestibular input.

  14. Frontal Plane Motion of the Pelvis and Hip during Gait Stance Discriminates Children with Diplegia Levels I and II of the GMFCS

    PubMed Central

    Kirkwood, Renata Noce; Franco, Rosa de Lourdes Lima Dias; Furtado, Sheyla Cavalcanti; Barela, Ana Maria Forti; Deluzio, Kevin John; Mancini, Marisa Cotta

    2012-01-01

    Objective. To determine if gait waveform could discriminate children with diplegic cerebral palsy of the GMFCS levels I and II. Patients. Twenty-two children with diplegia, 11 classified as level I and 11 as level II of the GMFCS, aged 7 to 12 years. Methods. Gait kinematics included angular displacement of the pelvis and lower limb joints during the stance phase. Principal components (PCs) analyses followed by discriminant analysis were conducted. Results. PC1s of the pelvis and hip in the frontal plane differ significantly between groups and captured 80.5% and 86.1% of the variance, respectively. PC1s captured the magnitude of the pelvic obliquity and hip adduction angle during the stance phase. Children GMFCS level II walked with reduced pelvic obliquity and hip adduction angles, and these variables could discriminate the groups with a cross-validation of 95.5%. Conclusion. Reduced pelvic obliquity and hip adduction were observed between children GMFCS level II compared to level I. These results could help the classification process of mild-to-moderate children with diplegia. In addition, it highlights the importance of rehabilitation programs designed to improve pelvic and hip mobility in the frontal plane of diplegic cerebral palsy children level II of the GMFCS. PMID:22792478

  15. Effects of interactive video-game based system exercise on the balance of the elderly.

    PubMed

    Lai, Chien-Hung; Peng, Chih-Wei; Chen, Yu-Luen; Huang, Ching-Ping; Hsiao, Yu-Ling; Chen, Shih-Ching

    2013-04-01

    This study evaluated the effects of interactive video-game based (IVGB) training on the balance of older adults. The participants of the study included 30 community-living persons over the age of 65. The participants were divided into 2 groups. Group A underwent IVGB training for 6 weeks and received no intervention in the following 6 weeks. Group B received no intervention during the first 6 weeks and then participated in training in the following 6 weeks. After IVGB intervention, both groups showed improved balance based on the results from the following tests: the Berg Balance Scale (BBS), Modified Falls Efficacy Scale (MFES), Timed Up and Go (TUG) test, and the Sway Velocity (SV) test (assessing bipedal stance center pressure with eyes open and closed). Results from the Sway Area (SA) test (assessing bipedal stance center pressure with eyes open and closed) revealed a significant improvement in Group B after IVGB training. Group A retained some training effects after 6 weeks without IVGB intervention. Additionally, a moderate association emerged between the Xavix measured step system stepping tests and BBS, MFES, Unipedal Stance test, and TUG test measurements. In conclusion, IVGB training improves balance after 6 weeks of implementation, and the beneficial effects partially remain after training is complete. Further investigation is required to determine if this training is superior to traditional physical therapy. PMID:23177921

  16. The effect of time-of-day on static and dynamic balance in recreational athletes.

    PubMed

    Heinbaugh, Erika M; Smith, Derek T; Zhu, Qin; Wilson, Margaret A; Dai, Boyi

    2015-09-01

    The purpose of this study was to investigate the effect of time-of-day (morning vs. afternoon) on static and dynamic balance in recreational athletes. A total of 34 recreational athletes completed the single-leg stance test with or without eyes open, lower quarter Y-balance test, upper quarter Y-balance test, and single-leg landing balance test in a random order in the morning (7:00-10:00 am) and afternoon (3:00-6:00 pm) for two consecutive days. Compared with the morning, participants demonstrated decreased centre of pressure (COP) sway areas (p = 0.002; Cohen's d (d) = 0.28) and sway speeds (p = 0.002; d = 0.17) during the eyes-open single-leg stance test, increased stance time (p = 0.031; d = 0.16) and decreased COP sway areas (p = 0.029; d = 0.22) during the eyes-closed single-leg stance test, and increased reaching distances (p = 0.024; d = 0.10) during the upper quarter Y-balance test in the afternoon. The between-day effect (day 1 vs. day 2) was observed for several parameters. Time-of-day had a minimal effect on dynamic balance and a noticeable effect on static balance. Time-of-day may be considered as a factor in designing balance training programmes and intervention studies for recreational athletes. PMID:26517605

  17. Behavioral data and neural correlates for postural prioritization and flexible resource allocation in concurrent postural and motor tasks.

    PubMed

    Huang, Cheng-Ya; Hwang, Ing-Shiou

    2013-03-01

    This study was undertaken to investigate the reciprocity effect between postural and suprapostural performances and its underlying neural mechanisms wherein subjects executed a perceptual-motor suprapostural task and maintained steady upright postures. Fourteen healthy individuals conducted force-matching maneuvers (static vs. dynamic) under two stance conditions (bipedal stance vs. unipedal stance); meanwhile, force-matching error, center of pressure dynamics, event-related potentials (ERPs), and the movement-related potential (MRP) were monitored. The behavioral results showed that force-matching error and postural sway were differently modulated by variations in stance pattern and force-matching version. Increase in postural challenge undermined the precision of static force-matching but facilitated a dynamic force-matching task. Both static and dynamic force-matching tasks improved postural control of unipedal stance but not of bipedal stance, in reference to the control conditions. ERP results revealed a stance-dependent N1 response, which was greater around the parietal cortex in the unipedal stance conditions. Instead, P2 was modulated by the effect of the suprapostural motor task, with a smaller P2 in the right parietal cortex for dynamic force-matching. Spatiotemporal evolution of the MRP commenced at the left frontal-central area and spread bilaterally over the frontal-central and parietal cortex. MRP onset was subject to an analogous interaction effect on force-matching performance. Our findings suggest postural prioritization and a structural alternation effect of stance pattern on postural performance, relevant to implicit expansion and selective allocation of central resources for relative task-loads of a postural-suprapostural task. PMID:22109987

  18. Comparison of a laboratory grade force platform with a Nintendo Wii Balance Board on measurement of postural control in single-leg stance balance tasks.

    PubMed

    Huurnink, Arnold; Fransz, Duncan P; Kingma, Idsart; van Dieën, Jaap H

    2013-04-26

    Training and testing of balance have potential applications in sports and medicine. Laboratory grade force plates (FP) are considered the gold standard for the measurement of balance performance. Measurements in these systems are based on the parameterization of center of pressure (CoP) trajectories. Previous research validated the inexpensive, widely available and portable Nintendo Wii Balance Board (WBB). The novelty of the present study is that FP and WBB are compared on CoP data that was collected simultaneously, by placing the WBB on the FP. Fourteen healthy participants performed ten sequences of single-leg stance tasks with eyes open (EO), eyes closed (EC) and after a sideways hop (HOP). Within trial comparison of the two systems showed small root-mean-square differences for the CoP trajectories in the x and y direction during the three tasks (mean±SD; EO: 0.33±0.10 and 0.31±0.16 mm; EC: 0.58±0.17 and 0.63±0.19 mm; HOP: 0.74±0.34 and 0.74±0.27 mm, respectively). Additionally, during all 420 trials, comparison of FP and WBB revealed very high Pearson's correlation coefficients (r) of the CoP trajectories (x: 0.999±0.002; y: 0.998±0.003). A general overestimation was found on the WBB compared to the FP for 'CoP path velocity' (EO: 5.3±1.9%; EC: 4.0±1.4%; HOP: 4.6±1.6%) and 'mean absolute CoP sway' (EO: 3.5±0.7%; EC: 3.7±0.5%; HOP: 3.6±1.0%). This overestimation was highly consistent over the 140 trials per task (r>0.996). The present findings demonstrate that WBB is sufficiently accurate in quantifying CoP trajectory, and overall amplitude and velocity during single-leg stance balance tasks. PMID:23528845

  19. Philip Morris's website and television commercials use new language to mislead the public into believing it has changed its stance on smoking and disease

    PubMed Central

    Friedman, Lissy C

    2007-01-01

    Objectives This paper analyses Philip Morris's evolving website and the legal strategies employed in its creation and dissemination. Methods Internal tobacco documents were searched and examined and their substance verified and triangulated using media accounts, legal and public health research papers, and visits to Philip Morris's website. Various drafts of website language, as well as informal discussion of the website's creation, were located in internal Philip Morris documents. I compared website statements pertaining to Philip Morris's stance on cigarette smoking and disease with statements made in tobacco trials. Results Philip Morris created and disseminated its website's message that it agreed that smoking causes disease and is addictive in an effort to sway public opinion, while maintaining in a litigation setting its former position that it cannot be proved that smoking causes disease or is addictive. Conclusions Philip Morris has not changed its position on smoking and health or addiction in the one arena where it has the most to lose—in the courtroom, under oath. PMID:18048599

  20. The effect of subtalar inversion/eversion on the dynamic function of the tibialis anterior, soleus, and gastrocnemius during the stance phase of gait.

    PubMed

    Wang, Ruoli; Gutierrez-Farewik, Elena M

    2011-05-01

    The purpose of this study was to determine how gait deviation in one plane (i.e. excessive subtalar inversion/eversion) can affect the dynamic function of the tibialis anterior, gastrocnemius, and soleus to accelerate the subtalar, ankle, knee and hip joints, as well as the body center of mass. Induced acceleration analysis was performed based on a subject-specific three-dimensional linkage model configured by stance phase gait data and driven by one unit of muscle force. Eight healthy adult subjects were examined in gait analysis. The subtalar inversion/eversion was modeled by offsetting up to 20° from the normal subtalar angle while other configurations remained unaltered. This study showed that the gastrocnemius, soleus and tibialis anterior generally functioned as their anatomical definition in normal gait, but counterintuitive function was occasionally found in the bi-articular gastrocnemius. The plantarflexors play important roles in the body support and forward progression. Excessive subtalar eversion was found to enlarge the plantarflexors and tibialis anterior's function. Induced acceleration analysis demonstrated its ability to isolate the contributions of individual muscle to a given factor, and as a means of studying effect of pathological gait on the dynamic muscle functions. PMID:21474318

  1. Higher Knee Flexion Moment During the Second Half of the Stance Phase of Gait Is Associated With the Progression of Osteoarthritis of the Patellofemoral Joint on Magnetic Resonance Imaging

    PubMed Central

    Teng, Hsiang-Ling; Macleod, Toran D.; Link, Thomas M.; Majumdar, Sharmila; Souza, Richard B.

    2016-01-01

    STUDY DESIGN Controlled laboratory study, longitudinal design. OBJECTIVE To examine whether baseline knee flexion moment or impulse during walking is associated with the progression of osteoarthritis (OA) with magnetic resonance imaging of the patellofemoral joint (PFJ) at 1 year. BACKGROUND Patellofemoral joint OA is highly prevalent and a major source of pain and dysfunction. The biomechanical factors associated with the progression of PFJ OA remain unclear. METHODS Three-dimensional gait analyses were performed at baseline. Magnetic resonance imaging of the knee (high-resolution, 3-D, fast spin-echo sequence) was used to identify PFJ cartilage and bone marrow edema–like lesions at baseline and a 1-year follow-up. The severity of PFJ OA progression was defined using the modified Whole-Organ Magnetic Resonance Imaging Score when new or increased cartilage or bone marrow edema–like lesions were observed at 1 year. Peak external knee flexion moment and flexion moment impulse during the first and second halves of the stance phase of gait were compared between progressors and nonprogressors, and used to predict progression after adjusting for age, sex, body mass index, and presence of baseline PFJ OA. RESULTS Sixty-one participants with no knee OA or isolated PFJ OA were included. Patellofemoral joint OA progressors (n = 10) demonstrated significantly higher peak knee flexion moment (P = .01) and flexion moment impulse (P = .04) during the second half of stance at baseline compared to nonprogressors. Logistic regression showed that higher peak knee flexion moment during the second half of the stance phase was significantly associated with progression at 1 year (adjusted odds ratio = 3.3, P = .01). CONCLUSION Peak knee flexion moment and flexion moment impulse during the second half of stance are related to the progression of PFJ OA and may need to be considered when treating individuals who are at risk of or who have PFJ OA. PMID:26161626

  2. Influence of visual feedback on successive control mechanisms in upright quiet stance in humans assessed by fractional Brownian motion modelling.

    PubMed

    Rougier, P

    1999-05-14

    An up-to-date way to model the centre of pressure (CP) trajectories may consist in using fractional Brownian motion (fBm). By doing so, one may note that standing still is in fact controlled by two separate and successive mechanisms. The point raised in this study concerns the nature of these control mechanisms and their level of interaction. Following this idea, visual feedback (VFB), which is known to affect postural control by significantly decreasing sway magnitudes, was used. Twelve healthy adults, instructed to stand as still as possible, were tested under this VFB protocol (via a PC screen). In order to model the CP trajectories as fBm, variograms (mean square distances, MSD, expressed as a function of increasing time intervals deltat) were bi-logarithmically plotted. The main visual effect of VFB on these variograms concerns longest latency scaling regimes which reveal less stochastic and consequently more accurate control (P < 0.05 and P < 0.01 for X and Y components, respectively). An increase in the MSD of the transition point, which corresponds to the switch between the two control mechanisms, is also noted (P < 0.05). Overall, evidence is provided from this data that long latency scaling regimes do operate through a feedback process. Interestingly, this improved determinism in feedback control in turn induces a similar effect on the control operating over the shortest deltat. Thus, by privileging a control strategy based on feedback mechanisms, VFB in turn would make the subjects quicker in their initial displacement in order to reach a position capable of initiating a feedback mechanism. PMID:10465697

  3. How does postural stability following a single leg drop jump landing task relate to postural stability during a single leg stance balance task?

    PubMed

    Fransz, Duncan P; Huurnink, Arnold; Kingma, Idsart; van Dieën, Jaap H

    2014-09-22

    We aimed to verify whether the static phase after a single leg drop jump (DJ) landing on a force plate may serve as a proxy for a single leg stance (SLS) balance task, as this would increase the application possibilities of landing tasks in the evaluation of sensorimotor function in relation to injury rehabilitation or performance assessment. Twenty-five healthy participants performed two sessions of five valid trials for both tasks in a reproducibility-agreement design. Three postural stability outcome measures ('COP speed', 'COP sway' and 'Horizontal GRF') were calculated for DJ (5-20s after landing) and for SLS (15s), and were averaged per session. Paired T-tests revealed a learning effect of SLS for postural stability (4.6-6.1%; P-values <0.03), in contrast to DJ (P-values >0.27). Only session 2 resulted in superior postural stability for SLS compared to DJ for 'COP speed' (5.0%; P=0.017) and 'Horizontal GRF' (8.2%; P=0.001). Bland and Altman methods demonstrated inter-session SD's of difference for DJ of 11-12% and for SLS of 10-12%, while inter-task SD's of difference ranged 10-17%. Precision ('SD within') was better for SLS concerning 'COP speed' (14-15% vs 13%) and 'Horizontal GRF' (18-20% vs 14-15%). In conclusion, postural stability during DJ and SLS cannot be considered interchangeable, due to a learning effect for SLS and inferior precision for DJ. However, a DJ task may be used as a proxy for static postural stability, although more than three trials are needed to achieve individual errors similar to SLS for 'COP speed' (4) and 'Horizontal GRF' (5). PMID:25016486

  4. Balance failure in single limb stance due to ankle sprain injury: an analysis of center of pressure using the fractal dimension method.

    PubMed

    Doherty, Cailbhe; Bleakley, Chris; Hertel, Jay; Caulfield, Brian; Ryan, John; Delahunt, Eamonn

    2014-01-01

    Instrumented postural control analysis plays an important role in evaluating the effects of injury on dynamic stability during balance tasks, and is often conveyed with measures based on the displacement of the center-of-pressure (COP) assessed with a force platform. However, the desired outcome of the task is frequently characterized by a loss of dynamic stability, secondary to injury. Typically, these failed trials are discarded during research investigations, with the potential loss of informative data pertaining to task success. The novelty of the present study is that COP characteristics of failed trials in injured participants are compared to successful trial data in another injured group, and a control group of participants, using the fractal dimension (FD) method. Three groups of participants attempted a task of eyes closed single limb stance (SLS): twenty-nine participants with acute ankle sprain successfully completed the task on their non-injured limb (successful injury group); twenty eight participants with acute ankle sprain failed their attempt on their injured limb (failed injury group); sixteen participants with no current injury successfully completed the task on their non-dominant limb (successful non-injured group). Between trial analyses of these groups revealed significant differences in COP trajectory FD (successful injury group: 1.58±0.06; failed injury group: 1.54±0.07; successful non-injured group: 1.64±0.06) with a large effect size (0.27). These findings demonstrate that successful eyes-closed SLS is characterized by a larger FD of the COP path when compared to failed trials, and that injury causes a decrease in COP path FD. PMID:24746034

  5. Time-Limited Psychotherapy With Adolescents

    PubMed Central

    Shefler, Gaby

    2000-01-01

    Short-term dynamic therapies, characterized by abbreviated lengths (10–40 sessions) and, in many cases, preset termination dates, have become more widespread in the past three decades. Short-term therapies are based on rapid psychodynamic diagnosis, a therapeutic focus, a rapidly formed therapeutic alliance, awareness of termination and separation processes, and the directive stance of the therapist. The emotional storm of adolescence, stemming from both developmental and psychopathological sources, leaves many adolescents in need of psychotherapy. Many adolescents in need of therapy resist long-term attachment and involvement in an ambiguous relationship, which they experience as a threat to their emerging sense of independence and separateness. Short-term dynamic therapy can be the treatment of choice for many adolescents because it minimizes these threats and is more responsive to their developmental needs. The article presents treatment and follow-up of a 17-year-old youth, using James Mann's time-limited psychotherapy method. PMID:10793128

  6. Leg Strength or Velocity of Movement Which Is More Influential on the Balance of Mobility Limited Elders?

    PubMed Central

    Mayson, Douglas J.; Kiely, Dan K.; LaRose, Sharon I.; Bean, Jonathan F.

    2009-01-01

    Objective To determine which component of leg power (maximal limb strength or limb velocity) is more influential on balance performance in mobility limited elders. Design In this cross-sectional analysis we evaluated 138 community-dwelling older adults with mobility limitation. Balance was measured using the Unipedal Stance Test, the Berg Balance Test (BERG), the Dynamic Gait Index, and the performance-oriented mobility assessment. We measured one repetition maximum strength and power at 40% one repetition maximum strength, from which velocity was calculated. The associations between maximal estimated leg strength and velocity with balance performance were examined using separate multivariate logistic regression models. Results Strength was found to be associated [odds ratio of 1.06 (95% confidence interval, 1.011.11)] with performance on the Unipedal Stance Test, whereas velocity showed no statistically significant association. In contrast, velocity was consistently associated with performance on all composite measures of balance [BERG 14.23 (1.84109.72), performance-oriented mobility assessment 33.92 (3.69312.03), and Dynamic Gait Index 35.80 (4.77268.71))]. Strength was only associated with the BERG 1.08 (1.011.14). Conclusions Higher leg press velocity is associated with better performance on the BERG, performance-oriented mobility assessment, and Dynamic Gait Index, whereas greater leg strength is associated with better performance on the Unipedal Stance Test and the BERG. These findings are likely related to the intrinsic qualities of each test and emphasize the relevance of limb velocity. PMID:19033758

  7. Educators' Stances toward Gender Issues in Literacy.

    ERIC Educational Resources Information Center

    Commeyras, Michelle; And Others

    A study examined literacy professionals' interest in gender issues in literacy education. A total of 1,519 K-12 teachers; reading specialists; teacher educators in reading, language arts, and related fields; library media specialists; and school administrators who make policy decisions related to literacy education completed a survey. Results…

  8. Stance and the Subjunctive in Isleno Spanish

    ERIC Educational Resources Information Center

    Coles, Felice A.

    2012-01-01

    Isleno Spanish speakers maintain few contexts firmly in the subjunctive (for example, adverbial clauses with the conjunctions "para que" and "antes que" and nominal clauses with "querer"), with most other semantic or syntactic categories optionally licensing the subjunctive. This study will outline the obligatory and optional uses of present and

  9. Error Correction: A Cognitive-Affective Stance

    ERIC Educational Resources Information Center

    Saeed, Aziz Thabit

    2007-01-01

    This paper investigates the application of some of the most frequently used writing error correction techniques to see the extent to which this application takes learners' cognitive and affective characteristics into account. After showing how unlearned application of these styles could be discouraging and/or damaging to students, the paper…

  10. Stance and the Subjunctive in Isleno Spanish

    ERIC Educational Resources Information Center

    Coles, Felice A.

    2012-01-01

    Isleno Spanish speakers maintain few contexts firmly in the subjunctive (for example, adverbial clauses with the conjunctions "para que" and "antes que" and nominal clauses with "querer"), with most other semantic or syntactic categories optionally licensing the subjunctive. This study will outline the obligatory and optional uses of present and…

  11. Mentoring Matters: Taking an Empathic Stance

    ERIC Educational Resources Information Center

    McCann, Thomas M.

    2011-01-01

    Too often, the school leaders who construct a school's master schedule and decide the teaching assignments for new teachers assign the newcomers the most difficult schedules. The difficulty might include multiple preparations for classes with the neediest and most-challenging students, and moves to three or four different classrooms throughout the…

  12. Taking a Democratic Stance toward Knowledge

    ERIC Educational Resources Information Center

    Traugh, Cecelia

    2009-01-01

    One of the major priorities that should guide teacher education programs in preparing teachers for their work in a democratic society is to develop a commitment to knowledge that embraces complexity and to place this knowledge into competition with the mainstream vision, which results from a deep reliance on standardized testing and controls much

  13. Phytol in a pharma-medico-stance.

    PubMed

    Islam, Md Torequl; de Alencar, Marcus Vinícius Oliveira Barros; da Conceição Machado, Katia; da Conceição Machado, Keylla; de Carvalho Melo-Cavalcante, Ana Amélia; de Sousa, Damiao Pergentino; de Freitas, Rivelilson Mendes

    2015-10-01

    This study aims to review phytol (PYT), through published articles, periodicals, magazines and patents, which were retrieved from the PM, SD, WS, SP; DII, WIPO, CIPO, USPTO and INPI databases. Among the 149 articles and 62 patents, 27.52% articles and 87.09% patients were found on the searched topic, PYT and its sources and synthesis and metabolism; then followed by 15.44% and 14.77% articles on PYT in cytotoxicity/cancer/mutagenicity/teratogenicity and PYT in neurological diseases, respectively. In the pharma-medico viewpoint, PYT and its derivatives have been evident to have antimicrobial, cytotoxic, antitumorous, antimutagenic, anti-teratogenic, antibiotic-chemotherapeutic, antidiabetic, lipid lowering, antispasmodic, anticonvulsant, antinociceptive, antioxidant, anti-inflammatory, anxiolytic, antidepressant, immunoadjuvancy, hair growth facilitator, hair fall defense and antidandruff activities. Otherwise, the important biometebolite of PYT is phytanic acid (PA). Evidence shows PA to have cytotoxic, anticancer, antidiabetic, lipid lowering and aniteratogenic activities. In addition, it may be considered as an important biomarker for some diseases such as Refsum's Disease (RD), Sjögren Larsson syndrome (SLS), rhizomelic chondrodysplasia punctata (RZCP), chronic polyneuropathy (CP), Zellweger's disease hyperpipecolic academia (ZDHA) and related diseases. Thus, phytol may be considered as a new drug candidate. PMID:26296761

  14. Time scale dependence of the center of pressure entropy: What characteristics of the neuromuscular postural control system influence stabilographic entropic half-life?

    PubMed

    Federolf, Peter; Zandiyeh, Payam; von Tscharner, Vinzenz

    2015-12-01

    The center of pressure (COP) movement in studies of postural control reveals a highly regular structure (low entropy) over short time periods and a highly irregular structure over large time scales (high entropy). Entropic half-life (EnHL) is a novel measure that quantifies the time over which short-term temporal correlations in a time series deteriorate to an uncorrelated, random structure. The current study suggested and tested three hypotheses about how characteristics of the neuromuscular postural control system may affect stabilometric EnHL: (H1) control system activity hypothesis: EnHL decreases with increased frequency of control system interventions adjusting COP motion; (H2) abundance of states hypothesis: EnHL decreases with increased number of mechanically equivalent states available to the postural system; and (H3) neurologic process hierarchy hypothesis: EnHL increases if postural control functions shift from the spinal level to the motor cortex. Thirty healthy participants performed quiet stance tests for 90 s in 18 different conditions: stance (bipedal, one-legged, and tandem); footwear (bare foot, regular sports shoe, and rocker sole shoes); and simultaneous cognitive task (two-back working memory task, no challenge). A four-way repeated-measures ANOVA revealed significant changes in EnHL for the different stance positions and for different movement directions (medio-lateral, anterior-posterior). These changes support H1 and H2. Significant differences were also found between rocker sole shoes and normal or barefoot standing, which supports H3. This study contributes to the understanding of how and why EnHL is a useful measure to monitor neuromuscular control of balance. PMID:26303025

  15. Flushing Time

    EPA Science Inventory

    The flushing time of an estuary is generally defined as the turnover time of fresh water in the estuary, that is, the time required to replace the fresh water contained in the estuary with freshwater inflow. Thus, the flushing time of an estuary is the ratio of the volume of fres...

  16. Reinventing Time

    ERIC Educational Resources Information Center

    Technology Teacher, 2004

    2004-01-01

    What do planet Earth, a swinging pendulum, a quartz crystal, and a Cesium atom have in common? They have all been used by humans to measure time. They represent humanity's progress through time in measuring time itself. But what is it, really, that humans set out to measure? Before time could be measured, somebody had to decide what to actually…

  17. Chua's Time

    NASA Astrophysics Data System (ADS)

    Buscarino, Arturo; Fortuna, Luigi; Frasca, Mattia

    2013-01-01

    We discuss the relationship between the idea of time of the philosopher Bergson and the concept of time recurrence in chaotic systems. By taking into account the Chua's circuit, we saw that the "Chua's time", i.e., the average recurrence time of trajectories in the Chua's circuit, is able to qualitatively represent the features of the Bergon's time. Numerical and experimental results are presented.

  18. Receiving shadows: governance and liminality in the night-time economy.

    PubMed

    Hobbs, D; Lister, S; Hadfield, P; Winlow, S; Hall, S

    2000-12-01

    This paper focuses upon the emergence of the night-time economy both materially and culturally as a powerful manifestation of post-industrial society. This emergence features two key processes: firstly a shift in economic development from the industrial to the post-industrial; secondly a significant orientation of urban governance involving a move away from the traditional managerial functions of local service provision, towards an entrepreneurial stance primarily focused on the facilitation of economic growth. Central to this new economic era is the identification and promotion of liminality. The State's apparent inability to control these new leisure zones constitutes the creation of an urban frontier that is governed by commercial imperatives. PMID:11140891

  19. Time out

    MedlinePlus

    ... punishing children may help them learn that physical violence or inflicting physical pain does NOT bring desired results. Children learn to avoid time out by stopping the behaviors that have caused time outs, or warnings of ...

  20. Bleeding time

    MedlinePlus

    Bleeding time is a medical test that measures how fast small blood vessels in the skin stop bleeding. ... until the bleeding stops. The provider records the time it takes for the cuts to stop bleeding.

  1. Managing time.

    PubMed

    Wachs, J E

    1993-06-01

    Managing time puts the occupational health nurse manager in control of health services and personal goals. Articulating those goals and appropriately delegating some of the outcomes needed to meet those goals should result in accomplishing the goals in less time. Strategies to control time expenditures on a daily basis include developing a "to do" list, avoiding procrastination, time wasters, and paper shuffling, creating an environment conducive to work, and rewarding self and staff for a job well done. PMID:8512614

  2. Time Honoured

    ERIC Educational Resources Information Center

    Campbell, Mora; Timmerman, Peter

    2007-01-01

    The vast majority of literature and practices in environmental education focuses on places and spaces. Little attention has been paid to time and temporalities as elements of environments, and the ways in which how we experience time affects our experience of place. This paper is an examination of the ways in which reflection on time can be…

  3. Time Out for Measuring Time.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1983-01-01

    The ability to measure time means being able to arrange events in logical sequences, predict which kinds of events take longer than others, and understand different divisions of time. Teaching methods and class activities that will help children develop skills and concepts concerning time usage are presented. (PP)

  4. TIMING APPARATUS

    DOEpatents

    Bennett, A.E.; Geisow, J.C.H.

    1956-04-17

    The timing device comprises an escapement wheel and pallet, a spring drive to rotate the escapement wheel to a zero position, means to wind the pretensioned spring proportional to the desired signal time, and a cam mechanism to control an electrical signal switch by energizing the switch when the spring has been wound to the desired position, and deenergizing it when it reaches the zero position. This device produces an accurately timed signal variably witain the control of the operator.

  5. Geologic time

    USGS Publications Warehouse

    Newman, William L.

    2000-01-01

    The Earth is very old 4 1/2 billion years or more according to recent estimates. This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for the key led to the beginning and nourished the growth of geologic science.

  6. Reaction time in gait initiation depends on the time available for affective processing.

    PubMed

    Gélat, Thierry; Chapus, Carole Ferrel

    2015-11-16

    Previous studies have reported that reaction time in gait initiation was affected by emotion eliciting pictures. This study examined the effect of a change in the delay between image onset and the imperative "go" on reaction time. From a standing posture, 19 young adults had to walk (several steps) toward pleasant or unpleasant images in two conditions. In the short condition, the word "go" appeared 500ms after image onset and participants were instructed to initiate gait as soon as possible after the word go appeared. In the long condition, the same procedure was used but the word "go" appeared 3000ms after image onset. Results demonstrated that motor responses were faster for pleasant pictures than unpleasant ones in the short condition. In contrast, no significant difference was found between both categories of pictures in the long condition. Moreover, we found that self ratings of valence of unpleasant pictures were less unpleasant in the long condition than in the short one whereas there was no difference for pleasant pictures between both conditions. This result reflected a change in the affective significance of unpleasant pictures in the long condition. We also found in the long condition, that the body was inclined forward and to the stance limb during the standing posture and importantly with a similar extent for pleasant and unpleasant pictures. This change clearly reflected a facilitation of the gait initiation process. Overall, results suggested that this gait facilitation when confronted to unpleasant pictures resulted from emotional regulation processes enabling to reappraise these pictures and to override the initial avoidance tendency that they caused. PMID:26455865

  7. Time Management

    ERIC Educational Resources Information Center

    Stoilov, Todor, Ed.

    2012-01-01

    The time management is worthy goal of many human activities. It concerns variety problems related to goals definition, assessment of available resources, control of management policies, scheduling of decisions. This book is an attempt to illustrate the decision making process in time management for different success stories, which can be used as

  8. Managing Time.

    ERIC Educational Resources Information Center

    Murphy, Linda; Della Corte, Suzanne

    1991-01-01

    This newsletter issue discusses time management techniques for parents of special needs children. Techniques include changing one's attitudes about perfection, prioritizing tasks, having a back-up plan, learning to say "no," asking for help, keeping things simple, hiring others, using waiting time wisely, and doing two things at once. Household…

  9. Time Management

    ERIC Educational Resources Information Center

    Stoilov, Todor, Ed.

    2012-01-01

    The time management is worthy goal of many human activities. It concerns variety problems related to goals definition, assessment of available resources, control of management policies, scheduling of decisions. This book is an attempt to illustrate the decision making process in time management for different success stories, which can be used as…

  10. Managing Time.

    ERIC Educational Resources Information Center

    Murphy, Linda; Della Corte, Suzanne

    1991-01-01

    This newsletter issue discusses time management techniques for parents of special needs children. Techniques include changing one's attitudes about perfection, prioritizing tasks, having a back-up plan, learning to say "no," asking for help, keeping things simple, hiring others, using waiting time wisely, and doing two things at once. Household

  11. Turnover Time

    EPA Science Inventory

    Ecosystems contain energy and materials such as carbon, nitrogen, phosphorus, and water, and are open to their flow-through. Turnover time refers to the amount of time required for replacement by flow-through of the energy or substance of interest contained in the system, and is ...

  12. Time ephemeris

    NASA Astrophysics Data System (ADS)

    Fukushima, T.

    1995-02-01

    The location-independent part of barycentric coordinate time and geocentric coordinate time (TCB-TCG), the difference between the two new time scales adopted by the IAU, was integrated numerically for three JPL planetary/lunar ephemerides; DE102, DE200, and DE245. The differences among these three integrations were mostly explained by the difference in the adopted constants of the ephemerides. It was shown that the post-Newtonian correction and the perturbation by asteroids are negligible except for the mean rate, LC. The comparison of these numerical integrations with the analytical formulas of Hirayama et al. (1987) and Fairhead & Bretagnon (1990) as well as their extended versions lead to the best estimate of LC as 1.480 826 845 7 x 10-8 + or - 1.0 x 10-17. Combining this with the recent value of the geoid potential in Bursa et al. (1992), we estimate the value of LB, the scale difference between TCB and terrestrial time (TT), as 1.550 519 748 x 10-8 + or - 4 x 10-17. This will be useful in converting the numerical values of some astronomical constants determined in the old IAU time scale barycentric dynamic time (TDB) to those in TCB. Also the paper will be useful when converting between TCB and TDB, i.e. the time scales themselves.

  13. Thrombin Time

    MedlinePlus

    ... monitor unfractionated heparin therapy and to detect heparin contamination in a blood sample. While it is still ... thrombin time may sometimes be ordered when heparin contamination of a sample is suspected or when a ...

  14. Time outs

    MedlinePlus

    ... Time-out technique for discipline. Children's Health Network web site. http://www.childrenshealthnetwork.org/CRS/CRS/pa_ ... a break from negative behavior. Massachusetts Medical Society web site. http://www.massmed.org/patient-care/health- ...

  15. About time

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1990-01-01

    Time has historically been a measure of progress of recurrent physical processes. Coordination of future actions, prediction of future events, and assigning order to events are three practical reasons for implementing clocks and signalling mechanisms. In large networks of computers, these needs lead to the problem of synchronizing the clocks throughout the network. Recent methods allow this to be done in large networks with precision around 1 millisecond despite mean message exchange times near 5 milliseconds. These methods are discussed.

  16. Number Time

    ERIC Educational Resources Information Center

    Herrera, Terese A.

    2004-01-01

    This article features Number Time, a site developed by the British Broadcasting Corporation (BBC) for young mathematics learners, located at www.bbc.co.uk/schools/numbertime. The site uses interactive animation to help children in pre-K through grade 2 understand and practice number basics. Users will find online games, videos that tell number…

  17. Time Out or Time Change?

    ERIC Educational Resources Information Center

    Anderson, Genan T.

    2001-01-01

    Recommends identifying elements in the physical classroom and the daily schedule that may contribute to children's aggressive behaviors. Suggests observing the child and looking at the daily routine as the basis for creating a suitable environment. Lists ways to reduce stimulation and stress, and identifies benefits of extended play time. (DLH)

  18. No Time for Time Out.

    ERIC Educational Resources Information Center

    Hannon, Jean

    2002-01-01

    Young students can benefit when teachers address behavior in positive, rather than punitive, ways. This paper describes how one teacher stopped using punitive time outs and instead developed a program in which working together on learning and having class responsibilities was meaningful enough that instances of troublesome behavior would be…

  19. Nurses' daily life: gender relations from the time spent in hospital1

    PubMed Central

    Pereira, Audrey Vidal

    2015-01-01

    Objective: to analyze the everyday life of nurses through the sexual work division as well as through interdependence relations and the time in hospital. Method: quanti-qualitative study, based on the Time Use Survey and in Norbert Elias's Configuration Theory of Interdependencies. Daily shifts distribution record, directed by 42 participants - with self-confrontation - by interviews which drew dialogues on subjective aspects of the everyday experiences related to use of time, based on a job at a university hospital. The theoretical intake that founded data analysis was based on concepts of conflicts of interest, power struggles, sexual work division and polychronic-monochronic concepts - whether the work environment demands multitasking nurses or not. Results: time records allowed to observe differences between the groups studied, useful to identify conflicts, tensions, power struggles and gender inequalities in interviewees' everyday affairs that do not only affect physical and mental health, but also their way of life. Conclusion: the analytical path pointed out the need for public policies that promote equity in gender relations, keeping at sight the exercise of plural discourses and tolerant stances capable to respect differences between individual and collective time. PMID:26487146

  20. Importance timing

    NASA Astrophysics Data System (ADS)

    Skilling, John

    2013-08-01

    Bayesian evidence Z = ? L(x)d?(x) is defined as likelihood L integrated over prior ?, and is often computed in that form with nested sampling as the preferred algorithm for passing from prior to posterior in large or complicated applications. However, a user may suspect that some locations x are more useful than others, and wish to guide the computation by using a suitable weight function w(x). In conventional importance sampling, such weights are incorporated by re-writing Z as ?(L/w)(wd?), using a weighted prior w? and correspondingly de-weighted likelihood L/w. Unfortunately, w cannot be updated during a run without altering the likelihood surfaces (which nested sampling requires to be fixed). Also, the normalization ? wd? must be known if the value of Z is to be retrieved. Importance timing removes those disadvantages by preserving the likelihood unchanged. Excess prior weight w is cancelled, not through L, but by adjusting the rate of the MCMC clock which defines termination of a trial exploration. This preserves the evidence value and enables the weights to be (slowly) learned as iterations proceed.

  1. Doing Time

    PubMed Central

    Yang, Suzanne; Kadouri, Alane; Révah-Lévy, Anne; Mulvey, Edward P.; Falissard, Bruno

    2009-01-01

    Once convicted, the perpetrator of serious crime embarks upon a new journey: the challenge of adjusting to long-term imprisonment. Prisoners’ views of incarceration and the meaning of this experience may affect their later adjustment to life in the community. On the basis of brief narrative responses collected during an epidemiological survey of the psychological health of prisoners in France, this study examined the impact of incarceration on psychological state in a group of 59 inmates serving long sentences. Qualitative content analysis and computer-assisted linguistic analysis (using ALCESTE software) were performed on the textual data of open responses to three standard questions. Using a combination of these two approaches, seven categories of the subjective experience of prisoners in the sample were identified: the Outside World, Others, Punishment, Time, Affects and Impulses, Self-Concept, and Speech. Further qualitative analyses were then performed to compare the responses of Severely Mentally Ill (SMI) subjects and subjects with no psychiatric disorder. These analyses revealed contrasting attitudes towards incarceration. SMI subjects spoke in more hostile and persecutory terms about their experience in prison, attributing suffering to external circumstances, while subjects with no psychiatric disorder evoked similar themes, but with an introspective attitude. The themes evoked by mentally ill individuals in our sample suggest that their reactions to the prison environment arise in part from aspects of their psychiatric symptoms, and this may have relevance to future mental health policy and practices in criminal corrections. PMID:19619895

  2. A study of the relationship between depression symptom and physical performance in elderly women.

    PubMed

    Lee, Yang Chool

    2015-12-01

    Depression is a general public health problem; there is an association between regular exercise or vigorous physical activity and depression. Physical activity has positive physical, mental, and emotional effects. The purpose of this study was to examine the relationship between depression symptom and physical performance in elderly women. A total of 173 elderly women aged 65 to 80 participated in this study. We evaluated elderly women using the 6-min walk, grip-strength, 30-sec arm curl, 30-sec chair stand, 8-foot up and go, back scratch, and chair sit and reach, and unipedal stance, measured the body mass index (BMI), and depression symptom assessed using Korean version of the Geriatric Depression Scale (GDS-K). The collected data were analyzed using descriptive statistics, correlation analysis, paired t-tests, and simple linear regression using IBM SPSS Statistics ver. 21.0. There were significant correlations between GDS-K and the 6-min walk, 30-sec chair stand, 30-sec arm curl, chair sit and reach, 8-foot up and go, and grip strength tests (P<0.05), but not BMI, back strength, and unipedal stance. When divided into two groups (GDS-K score≥14 and GDS-K score<14), there was a difference between the two groups in the 6-min walk, 30-sec chair stand, 30-sec arm curl test, chair sit and reach, 8-foot up and go test, and grip strength test performances. Physical performance factors were strongly associated with depression symptom, suggesting that physical performance improvements may play an important role in preventing depression. PMID:26730389

  3. A study of the relationship between depression symptom and physical performance in elderly women

    PubMed Central

    Lee, Yang Chool

    2015-01-01

    Depression is a general public health problem; there is an association between regular exercise or vigorous physical activity and depression. Physical activity has positive physical, mental, and emotional effects. The purpose of this study was to examine the relationship between depression symptom and physical performance in elderly women. A total of 173 elderly women aged 65 to 80 participated in this study. We evaluated elderly women using the 6-min walk, grip-strength, 30-sec arm curl, 30-sec chair stand, 8-foot up and go, back scratch, and chair sit and reach, and unipedal stance, measured the body mass index (BMI), and depression symptom assessed using Korean version of the Geriatric Depression Scale (GDS-K). The collected data were analyzed using descriptive statistics, correlation analysis, paired t-tests, and simple linear regression using IBM SPSS Statistics ver. 21.0. There were significant correlations between GDS-K and the 6-min walk, 30-sec chair stand, 30-sec arm curl, chair sit and reach, 8-foot up and go, and grip strength tests (P<0.05), but not BMI, back strength, and unipedal stance. When divided into two groups (GDS-K score≥14 and GDS-K score<14), there was a difference between the two groups in the 6-min walk, 30-sec chair stand, 30-sec arm curl test, chair sit and reach, 8-foot up and go test, and grip strength test performances. Physical performance factors were strongly associated with depression symptom, suggesting that physical performance improvements may play an important role in preventing depression. PMID:26730389

  4. A Rhetorical Stance on the Archives of Civic Action.

    ERIC Educational Resources Information Center

    Miller, Thomas P.; Bowdon, Melody

    1999-01-01

    Contextualizes the rhetorical archive and moves beyond composition to the traditions of civic discourse, classical rhetorical theory, and moral philosophy. Wonders what kind of archive of actual historical practices would enable rhetoricians to confirm or qualify the existence of a genuine tradition of civic discourse. (RS)

  5. Investigating Asynchronous Online Communication: A Connected Stance Revealed

    ERIC Educational Resources Information Center

    Wegmann, Susan J.; McCauley, Joyce K.

    2014-01-01

    This research project explores the effects of altering the structure of discussion board formats to increase students' engagement and participation. This paper will present the findings of a two-university, two-class research project in which asynchronous discussion board entries were analyzed for substance. By using oral discourse analysis…

  6. Toward an Intercultural Stance: Teaching German and English through Telecollaboration

    ERIC Educational Resources Information Center

    Ware, Paige D.; Kramsch, Claire

    2005-01-01

    We discuss the challenges of Web-based teaching for language teachers and then describe in detail an extended episode of misunderstanding that occurred between 2 students discussing their versions of history during a classroom-based, asynchronous telecollaborative project between learners of German in the United States and learners of English in…

  7. Taking the Intentional Stance at 12 Months of Age.

    ERIC Educational Resources Information Center

    Gergely, Gyorgy; And Others

    1995-01-01

    In a visual habituation experiment, infants watched a circle (the "agent") move toward another circle by jumping over a barrier or jumping without a barrier present, and then watched a circle move straight to another circle. Found that infants were able to identify the agent's spatial goal and to interpret the agent's actions causally in relation…

  8. Place-based education: a transformative activist stance

    NASA Astrophysics Data System (ADS)

    Coughlin, Christine A.; Kirch, Susan A.

    2010-12-01

    The ethnography presented by van Eijck and Roth focuses on the activities of people involved in a government funded internship program in conservation and restoration, which was offered by a `multidisciplinary research center' through a local First Nation adult education center. The internship was designed, in partnership with a local non-profit conservation society (OceanHealth), to appeal to First Nation men and women considering career change, returning to school, or re-entering the work place. The primary aim of the internship was to `provide authentic science for diverse student populations (and their teachers), with particular attention to the needs of students from First Nations, to become scientifically literate to the extent that it prepares them for participating in public debates, community decision-making, and personal living consistent with long-term environmentally sustainable forms of life'. The authors report that at least one of the two interns was not interested in science and a WSÁNEC elder expressed dissatisfaction with the efforts to establish the nature park and its current approved uses. Van Eijck and Roth argue that the divergence between the project aims and the goals of the participants are a result of how `place' is viewed in place-based education and that disagreements like these can be resolved if place is theorized as chronotope. There are many interesting ideas raised and directions taken in the article by van Eijck and Roth. After several discussions during the review process, we decided to focus our forum response on the meaning of `place' in place-based education, the utility of theorizing place as a chronotope, the implications for teaching-learning (`education'), and musings on what remains unclear.

  9. Making the Turn: Fostering an Inquiry Stance in Teacher Education

    ERIC Educational Resources Information Center

    Hulburt, Kevin J.; Knotts, Michelle

    2012-01-01

    In this article, the authors describe how an examination of teacher candidate inquiry projects led to an examination of their own experiences as teacher education practitioner-researchers and competing narratives about education research. They describe how in the process of doing research, they came to recognise how their experiences and…

  10. Teachers' Stances towards Chinese International Students: An Australian Case Study

    ERIC Educational Resources Information Center

    Love, Kristina; Arkoudis, Sophie

    2006-01-01

    The international marketing of school education has gathered momentum in the Asia Pacific region, where an English medium education is prized by many parents. This paper investigates the responses of a group of teachers in Australia to the needs of international students in their school. The analysis of a 1 h professional discussion between four

  11. Teachers' Stances towards Chinese International Students: An Australian Case Study

    ERIC Educational Resources Information Center

    Love, Kristina; Arkoudis, Sophie

    2006-01-01

    The international marketing of school education has gathered momentum in the Asia Pacific region, where an English medium education is prized by many parents. This paper investigates the responses of a group of teachers in Australia to the needs of international students in their school. The analysis of a 1 h professional discussion between four…

  12. Pleasure, Learning, Video Games, and Life: The Projective Stance

    ERIC Educational Resources Information Center

    Gee, James Paul

    2005-01-01

    This article addresses three questions. First, what is the deep pleasure that humans take from video games? Second, what is the relationship between video games and real life? Third, what do the answers to these questions have to do with learning? Good commercial video games are deep technologies for recruiting learning as a form of profound…

  13. Contemplating a Constructivist Stance for Active Learning within Music Education

    ERIC Educational Resources Information Center

    Scott, Sheila

    2011-01-01

    This article examines constructivist philosophies for learning with an emphasis on student-centered environments in education and the active involvement of students in learning as they relate new understanding to what they already know and refine previous skills in terms of newly acquired proficiencies. Active learning is explored from a…

  14. Place-Based Education: A Transformative Activist Stance

    ERIC Educational Resources Information Center

    Coughlin, Christine A.; Kirch, Susan A.

    2010-01-01

    The ethnography presented by van Eijck and Roth focuses on the activities of people involved in a government funded internship program in conservation and restoration, which was offered by a "multidisciplinary research center" through a local First Nation adult education center. The internship was designed, in partnership with a local non-profit…

  15. Reasons Given by UK Churchgoers for Their Stance on Evolution

    ERIC Educational Resources Information Center

    Village, Andrew; Baker, Sylvia

    2013-01-01

    A sample of 661 churchgoers from a range of Christian denominations in the United Kingdom was asked about Darwinian evolution (defined as the common origin of all species, including humans). Respondents were categorised as those who accepted the idea, those who rejected it, and those who were unsure or neutral. People in each category were given a

  16. Taking someone else's spatial perspective: Natural stance or effortful decentring?

    PubMed

    Arnold, Gabriel; Spence, Charles; Auvray, Malika

    2016-03-01

    When perceiving stimuli, self-centred and decentred perspectives can be adopted. In the present study, we investigate whether perceivers have a natural perspective that constrains their spatial perception, with some people perceiving better with self-centred than decentred perspectives and vice versa for other people. We used a recognition task of tactile ambiguous letters (b, d, p, and q) presented on the stomach, for which three perspectives can be adopted (trunk-centred, head-centred, and decentred). At first, the participants were free to adopt any perspective they wanted. Then, either the same or a different perspective was imposed on them. Without constraints, 80% of the participants adopted a self-centred perspective (50% trunk-centred, 30% head-centred) and 20% a decentred one. The perspective adopted freely appears to be natural as recognition performance decreases with a different perspective and returns to its previous high level with the same perspective. Thus, to perceive space, some perceivers adopt naturally a perspective centred on themselves whereas others take naturally others' perspective. PMID:26722709

  17. Expression of Epistemic Stance in EFL Chinese University Students' Writing

    ERIC Educational Resources Information Center

    Chen, Zhenzhen

    2012-01-01

    This paper reported findings on a contrastive analysis of epistemic expressions in argumentative essays between NS and NNS Chinese L2 writers. Based on an examination of a NS corpus and a NNS learner corpus across four proficiency levels, the study shows there is great similarity in the total number of epistemic devices used per thousand words…

  18. Conveying a Stance of Religious Pluralism in Children's Literature

    ERIC Educational Resources Information Center

    Sanders, Jennifer; Foyil, Kris; Graff, Jennifer M.

    2010-01-01

    Religious discrimination is a global concern, as social dissonance and devastating violence result from religious intolerance. In order to develop socially competent, global citizens and create a peaceful society, religious diversity must be explored in public school classrooms; yet it remains a controversial and seldom addressed topic. Children's…

  19. Illuminating a Dialectical Transformative Activist Stance in Education

    ERIC Educational Resources Information Center

    Ritchie, Stephen M.

    2008-01-01

    In this essay I comment on Stetsenko's (2008) essay that draws together the work of Vygotsky, Piaget and Dewey, as she attempts to counter the "new" reductionist synthesis in public educational policy. While this theoretical work is helpful, it could be enhanced further by illuminating everyday practices of learners. I pose some questions that…

  20. Human Genetic Engineering: A Survey of Student Value Stances

    ERIC Educational Resources Information Center

    Wilson, Sara McCormack; And Others

    1975-01-01

    Assesses the values of high school and college students relative to human genetic engineering and recommends that biology educators explore instructional strategies merging human genetic information with value clarification techniques. (LS)

  1. Dialogic Teaching: Talk in Service of a Dialogic Stance

    ERIC Educational Resources Information Center

    Boyd, Maureen Patricia; Markarian, William C.

    2011-01-01

    We consider what it means to be a dialogic teacher as characterized by Paulo Freire and Robin Alexander, and utilizing discourse analysis, we explicate how one elementary teacher's talk reflects these characteristics. We provide context for and analysis of a seven-minute discussion selected as a cumulative achievement the focal nine-year-olds are…

  2. [Nursing stance in the face of Jinn possession in Mayotte].

    PubMed

    Gillard-Berthod, Claire

    2013-01-01

    Caregivers and nursing students practising in Mayotte can find themselves in a difficult position when faced with patients believing themselves to be possessed by spirits called Jinn. Through a multidisciplinary roundtable, different perspectives and practices can be shared leading to a more enlightened treatment of patients which respects their beliefs, blending traditional and modern medicine. PMID:24245404

  3. Reasons Given by UK Churchgoers for Their Stance on Evolution

    ERIC Educational Resources Information Center

    Village, Andrew; Baker, Sylvia

    2013-01-01

    A sample of 661 churchgoers from a range of Christian denominations in the United Kingdom was asked about Darwinian evolution (defined as the common origin of all species, including humans). Respondents were categorised as those who accepted the idea, those who rejected it, and those who were unsure or neutral. People in each category were given a…

  4. Links between Parents' Epistemological Stance and Children's Evidence Talk

    ERIC Educational Resources Information Center

    Luce, Megan R.; Callanan, Maureen A.; Smilovic, Sarah

    2013-01-01

    Recent experimental research highlights young children's selectivity in learning from others. Little is known, however, about the patterns of information that children actually encounter in conversations with adults. This study investigated variation in parents' tendency to focus on testable evidence as a way to answer science-related questions…

  5. Urban Teacher Education in Partnership: An Inquiry Stance Sustains Collaboration

    ERIC Educational Resources Information Center

    Stairs, Andrea J.

    2010-01-01

    The relationship between Brighton High School (BHS) and Boston College (BC) spans several decades. Professors from multiple departments at the university--not only teacher educators but professors of psychology, measurement, and arts and sciences--have walked, as regular parts of the school community, the halls of the gothic-style high school…

  6. Dialogic Teaching: Talk in Service of a Dialogic Stance

    ERIC Educational Resources Information Center

    Boyd, Maureen Patricia; Markarian, William C.

    2011-01-01

    We consider what it means to be a dialogic teacher as characterized by Paulo Freire and Robin Alexander, and utilizing discourse analysis, we explicate how one elementary teacher's talk reflects these characteristics. We provide context for and analysis of a seven-minute discussion selected as a cumulative achievement the focal nine-year-olds are

  7. Assisted dying - should the UK change its stance?

    PubMed

    Gordon, Daniel; Raphael, Claire E; Vassiliou, Vassilios

    2015-04-01

    Along with an increasing interest in assisted dying by many European and North American countries, some of which have already modified their existing laws to accommodate this, the interest in assisted dying in the UK has increased once again following Lord Falconer's Assisted Dying for the Terminally Ill Bill. Drawing on examples from countries where similar assisted dying laws are already in place, this article analyses and contextualises the proposed bill and discusses its potential pitfalls and benefits for the UK. PMID:25628340

  8. Illuminating a dialectical transformative activist stance in education

    NASA Astrophysics Data System (ADS)

    Ritchie, Stephen M.

    2008-07-01

    In this essay I comment on Stetsenko's (2008) essay that draws together the work of Vygotsky, Piaget and Dewey, as she attempts to counter the `new' reductionist synthesis in public educational policy. While this theoretical work is helpful, it could be enhanced further by illuminating everyday practices of learners. I pose some questions that might provoke ongoing discussions by researchers as they transform collaboratively cultural-historical activity theory.

  9. Pleasure, Learning, Video Games, and Life: The Projective Stance

    ERIC Educational Resources Information Center

    Gee, James Paul

    2005-01-01

    This article addresses three questions. First, what is the deep pleasure that humans take from video games? Second, what is the relationship between video games and real life? Third, what do the answers to these questions have to do with learning? Good commercial video games are deep technologies for recruiting learning as a form of profound

  10. Statistical Parametric Mapping (SPM) for alpha-based statistical analyses of multi-muscle EMG time-series.

    PubMed

    Robinson, Mark A; Vanrenterghem, Jos; Pataky, Todd C

    2015-02-01

    Multi-muscle EMG time-series are highly correlated and time dependent yet traditional statistical analysis of scalars from an EMG time-series fails to account for such dependencies. This paper promotes the use of SPM vector-field analysis for the generalised analysis of EMG time-series. We reanalysed a publicly available dataset of Young versus Adult EMG gait data to contrast scalar and SPM vector-field analysis. Independent scalar analyses of EMG data between 35% and 45% stance phase showed no statistical differences between the Young and Adult groups. SPM vector-field analysis did however identify statistical differences within this time period. As scalar analysis failed to consider the multi-muscle and time dependence of the EMG time-series it exhibited Type II error. SPM vector-field analysis on the other hand accounts for both dependencies whilst tightly controlling for Type I and Type II error making it highly applicable to EMG data analysis. Additionally SPM vector-field analysis is generalizable to linear and non-linear parametric and non-parametric statistical models, allowing its use under constraints that are common to electromyography and kinesiology. PMID:25465983

  11. Time-to-contact and multiscale entropy identify differences in postural control in adolescent idiopathic scoliosis.

    PubMed

    Gruber, Allison H; Busa, Michael A; Gorton Iii, George E; Van Emmerik, Richard E A; Masso, Peter D; Hamill, Joseph

    2011-05-01

    Previous reports on changes in postural control in adolescent idiopathic scoliosis (AIS) compared to healthy controls have been inconsistent. This may suggest center of pressure (COP) sway parameters are not sufficient for determining the ability to maintain quiet upright stance indicating more complex measures may be needed to examine postural control in AIS. The purpose of this investigation was to compare postural control between AIS of different severity levels and healthy controls using time-to-contact (TtC), the complexity index of multiscale entropy (C(r)), and COP sway parameters. Thirty-six AIS patients were classified as pre-bracing or pre-operative and compared to 10 healthy control subjects. Overall, the AIS patients showed significantly greater COP sway in mediolateral direction, but deficits with respect to the anteroposterior direction were only systematically identified with the time-to-contact and entropy measures. The multiscale entropy (C(r)) results indicate that those with AIS utilize a different control strategy from healthy controls in the mediolateral direction that is more constrained, less complex and less adaptable. AIS severity further reduced this adaptability in the anteroposterior direction. These results indicate it is necessary to examine both planes of motion when investigating postural control in AIS. Additionally, the application of the measures used to assess the nature of the postural control changes in AIS should also be considered. PMID:21478018

  12. Evidence for a Time-Invariant Phase Variable in Human Ankle Control

    PubMed Central

    Gregg, Robert D.; Rouse, Elliott J.; Hargrove, Levi J.; Sensinger, Jonathon W.

    2014-01-01

    Human locomotion is a rhythmic task in which patterns of muscle activity are modulated by state-dependent feedback to accommodate perturbations. Two popular theories have been proposed for the underlying embodiment of phase in the human pattern generator: a time-dependent internal representation or a time-invariant feedback representation (i.e., reflex mechanisms). In either case the neuromuscular system must update or represent the phase of locomotor patterns based on the system state, which can include measurements of hundreds of variables. However, a much simpler representation of phase has emerged in recent designs for legged robots, which control joint patterns as functions of a single monotonic mechanical variable, termed a phase variable. We propose that human joint patterns may similarly depend on a physical phase variable, specifically the heel-to-toe movement of the Center of Pressure under the foot. We found that when the ankle is unexpectedly rotated to a position it would have encountered later in the step, the Center of Pressure also shifts forward to the corresponding later position, and the remaining portion of the gait pattern ensues. This phase shift suggests that the progression of the stance ankle is controlled by a biomechanical phase variable, motivating future investigations of phase variables in human locomotor control. PMID:24558485

  13. Age-related differences in postural reaction time and coordination during voluntary sway movements.

    PubMed

    Tucker, Murray G; Kavanagh, Justin J; Barrett, Rod S; Morrison, Steven

    2008-10-01

    The elderly are known to exhibit declines in postural control during standing and walking, however little is known about how the elderly react under time-critical and challenging postural situations. The purpose of this study was to examine age-related differences in reaction time (RT) and the pattern of temporal coordination between center of pressure (COP), trunk and head motion during voluntary postural sway movements. Healthy young (n=10; mean=24 years; SD=5 years) and elderly men (n=8; mean=75 years; SD=2 years) stood on a force plate with tri-axial accelerometers attached to the head and lower trunk. Participants were required to generate sway in the anterior-posterior (AP) or medial-lateral (ML) direction in response to an auditory cue during two different testing conditions called Static reaction and Dynamic reaction. Static reactions involved the initiation of voluntary sway in either the AP or ML direction from quiet stance. Dynamic reactions involved an orthogonal switch of voluntary sway between the AP and ML directions. Compared to the young, elderly individuals exhibited slower RT during both Static and Dynamic reaction, and smaller differences in RT and phasing between COP, trunk, and head motion. The results of this study suggest that the elderly adopted more rigid coordination strategies compared to the young when executing a rapid change in direction of whole body motion. The rigid movement strategy of the elderly was presumably generated in an effort to compensate for increased challenge to the maintenance of stability. PMID:18513814

  14. A robust real-time gait event detection using wireless gyroscope and its application on normal and altered gaits.

    PubMed

    Gouwanda, Darwin; Gopalai, Alpha Agape

    2015-02-01

    Gait events detection allows clinicians and biomechanics researchers to determine timing of gait events, to estimate duration of stance phase and swing phase and to segment gait data. It also aids biomedical engineers to improve the design of orthoses and FES (functional electrical stimulation) systems. In recent years, researchers have resorted to using gyroscopes to determine heel-strike (HS) and toe-off (TO) events in gait cycles. However, these methods are subjected to significant delays when implemented in real-time gait monitoring devices, orthoses, and FES systems. Therefore, the work presented in this paper proposes a method that addresses these delays, to ensure real-time gait event detection. The proposed algorithm combines the use of heuristics and zero-crossing method to identify HS and TO. Experiments involving: (1) normal walking; (2) walking with knee brace; and (3) walking with ankle brace for overground walking and treadmill walking were designed to verify and validate the identified HS and TO. The performance of the proposed method was compared against the established gait detection algorithms. It was observed that the proposed method produced detection rate that was comparable to earlier reported methods and recorded reduced time delays, at an average of 100 ms. PMID:25619613

  15. The Time-Pressure Illusion: Discretionary Time vs. Free Time

    ERIC Educational Resources Information Center

    Goodin, Robert E.; Rice, James Mahmud; Bittman, Michael; Saunders, Peter

    2005-01-01

    People's welfare is a function of both time and money. People can--and, it is said, increasingly do--suffer time-poverty as well as money-poverty. It is undeniably true that people feel increasingly time pressured, particularly in dual-earner households. But much of the time devoted to paid and unpaid tasks is over and above that which is strictly…

  16. Being, doing, knowing, and becoming: Science and opportunities for learning in the out-of-school-time setting

    NASA Astrophysics Data System (ADS)

    Bevan, Bronwyn

    This dissertation addresses the question of how structured out-of-school-time settings, such as afterschool programs and summer camps, are positioned to support children's engagement and learning in science. This study addresses a gap in the research literature that does not fully specify the nature of the out-of-school-time (OST) setting and that generally does not position learning and development in relationship to one another, instead focusing on one or the other. As a result of an incomplete conceptualization of the OST setting as a site for learning and development, the OST field is becoming increasingly academicized, and its developmental qualities and benefits for children are under siege. A transformative activist stance (Stetsenko, 2008) guides my goals in undertaking this study -- to produce knowledge that can inform the design and implementation of OST science programs -- and it also guides my analysis of what constitutes learning in OST science. A transformative activist stance is a perspective on cultural-historical theory that understands individual development as occurring through agentive, goal-directed efforts to change one's self and one's world. These goals and actions are always developed and enacted in cultural-historical context. Learning, which occurs through the appropriation of cultural tools and schema to achieve one's purposes, and which leads human development, is understood broadly, as entailing processes of being, doing, knowing and becoming (see Herrenkohl & Mertl, in press). I also draw on bioecological theory (Bronfenbrenner, 1979) to analyze the proximal processes that support and sustain children's participation in the OST setting. In this study, I analyze the structural, developmental, and conceptual features of three different OST science programs to understand how they create opportunities for learning and engagement in science. The contributions of this study are to better specify the nature of the OST science program setting and to better conceptualize how learning and development relate to one another in the context of OST science. I draw on my analysis to make recommendations for ways in which OST science learning can be expanded and enriched for more children in more settings.

  17. Time as a Resource.

    ERIC Educational Resources Information Center

    Saxby, K. L.

    1984-01-01

    Outlines the organization of time in a British secondary school, including class scheduling and time allocation. The author believes that effective time organization produces effective learning environments. (MD)

  18. Neuropsychology of Timing and Time Perception

    ERIC Educational Resources Information Center

    Meck, W.H.

    2005-01-01

    Interval timing in the range of milliseconds to minutes is affected in a variety of neurological and psychiatric populations involving disruption of the frontal cortex, hippocampus, basal ganglia, and cerebellum. Our understanding of these distortions in timing and time perception are aided by the analysis of the sources of variance attributable…

  19. Time on Your Hands: Modeling Time

    ERIC Educational Resources Information Center

    Finson, Kevin; Beaver, John

    2007-01-01

    Building physical models relative to a concept can be an important activity to help students develop and manipulate abstract ideas and mental models that often prove difficult to grasp. One such concept is "time". A method for helping students understand the cyclical nature of time involves the construction of a Time Zone Calculator through a…

  20. Prothrombin time (PT)

    MedlinePlus

    PT; Pro-time; Anticoagulant-prothrombin time; Clotting time: protime; INR; International normalized ratio ... PT is measured in seconds. Most of the time, results are given as what is called INR ( ...

  1. Intelligence, Inspection Time, and Decision Time.

    ERIC Educational Resources Information Center

    Bates, Timothy C.; Eysenck, Hans J.

    1993-01-01

    Relationships among Multidimensional Aptitude Battery scores, inspection time, choice reaction time, and the odd-man procedure were investigated for 63 female and 25 male adults. No significant relationships were found for these mental speed measures and the Eysenck Personality Questionnaire-Revised dimensions of extraversion, neuroticism, and…

  2. History without time: Buffon's natural history as a nonmathematical physique.

    PubMed

    Hoquet, Thierry

    2010-03-01

    While "natural history" is practically synonymous with the name of Buffon, the term itself has been otherwise overlooked by historians of science. This essay attempts to address this omission by investigating the meanings of "physique," "natural philosophy," and "history," among other terms, with the purpose of understanding Buffon's actual objectives. It also shows that Buffon never claimed to be a Newtonian and should not be considered as such; the goal is to provide a historical analysis that resituates Buffon's thought within his own era. This is done, primarily, by eschewing the often-studied question of time in Buffon. Instead, this study examines the nontemporal meanings of the word "history" within the naturalist's theory and method. The title of his Natural History is examined both as an indicator of the kind of science that Buffon was hoping to achieve and as a source of great misinterpretation among his peers. Unlike Buffon, many of his contemporaries actually envisioned the study of nature from a Baconian perspective where history was restricted to the mere collection of facts and where philosophy, which was the implicit and ultimate goal of studying nature, was seen, at least for the present, as unrealizable. Buffon confronts this tendency insofar as his Histoire naturelle claims to be the real physique that, along with describing nature, also sought to identify general laws and provide clear insight into what true knowledge of nature is or should be. According to Buffon, history (both natural and civil) is not analogous to mathematics; it is a nonmathematical method whose scope encompasses both nature and society. This methodological stance gives rise to the "physicization" of certain moral concepts--a gesture that was interpreted by his contemporaries as Epicurean and atheist. In addition, Buffon reduces a number of metaphysically tainted historical concepts (e.g., antediluvian monuments) to objects of physical analysis, thereby confronting the very foundation of natural theology. In Buffon, as this essay makes clear, natural history is paving the way for a new physique (science of natural beings), independent from mathematics and from God, that treats naturalia in a philosophical and "historical" manner that is not necessarily "temporal." PMID:20575489

  3. Make time to move

    MedlinePlus

    Exercise - time to move; Weight loss - time to move; Obesity - time to move ... Getting regular exercise benefits your health in many ways: Strengthens your heart and lungs Lowers your risk for heart disease and ...

  4. Toddler Reading Time

    MedlinePlus

    ... a day of quality programming. previous continue Choosing Books for Toddlers Toddlers want to feel included and ... story time turns into sing-along time. Keeping Books Available Read-aloud time isn't the only ...

  5. Time's Arrows Today

    NASA Astrophysics Data System (ADS)

    Savitt, Steven F.

    1997-06-01

    Introduction; Part I. Cosmology and Time's Arrow: 1. Time, gravity, and quantum mechanics W. Unruh; 2. Cosmology, time's arrow, and that old double standard H. Price; Part II. Quantum Theory and Time's Arrow: 3. Time's arrow and the quantum measurement problem A. Leggett; 4. Time, decoherence, and 'reversible' measurements P. Stamp; 5. Time flows, non-locality, and measurement in quantum mechanics S. McCall; 6. Stochastically branching spacetime topology R. Douglas; Part III. Thermodynamics and Time's Arrow: 7. The elusive object of desire: in pursuit of the kinetic equations and the second law L. Sklar; 8. Time in experience and in theoretical description of the world L. Sklar; 9. When and why does entropy increase? M. Barrett and E. Sober; Part IV. Time Travel and Time's Arrow: 10. Closed causal chains P Horwich; 11. Recent work on time travel J. Earman.

  6. From Time to Time: Processing Time Reference Violations in Dutch

    ERIC Educational Resources Information Center

    Dragoy, Olga; Stowe, Laurie A.; Bos, Laura S.; Bastiaanse, Roelien

    2012-01-01

    Time reference in Indo-European languages is marked on the verb. With tensed verb forms, the speaker can refer to the past (wrote, has written), present (writes, is writing) or future (will write). Reference to the past through verb morphology has been shown to be particularly vulnerable in agrammatic aphasia and both agrammatic and…

  7. On Time-II: Newton's Time.

    ERIC Educational Resources Information Center

    Raju, C. K.

    1991-01-01

    A study of time in Newtonian physics is presented. Newton's laws of motion, falsifiability and physical theories, laws of motion and law of gravitation, and Laplace's demon are discussed. Short bibliographic sketches of Laplace and Karl Popper are included. (KR)

  8. Time domain reflectometry in time variant plasmas

    NASA Technical Reports Server (NTRS)

    Scherner, Michael J.

    1992-01-01

    The effects of time-dependent electron density fluctuations on a synthesized time domain reflectometry response of a one-dimensional cold plasma sheath are considered. Numerical solutions of the Helmholtz wave equation, which describes the electric field of a normally incident plane wave in a specified static electron density profile, are used. A study of the effects of Doppler shifts resulting from moving density fluctuations in the electron density profile of the sheath is included. Varying electron density levels corrupt time domain and distance measurements. Reducing or modulating the electron density levels of a given electron density profile affects the time domain response of a plasma and results in motion of the turning point, and the effective motion has a significant effect on measuring electron density locations.

  9. Occupational Cohort Time Scales

    PubMed Central

    Roth, H. Daniel

    2015-01-01

    Purpose: This study explores how highly correlated time variables (occupational cohort time scales) contribute to confounding and ambiguity of interpretation. Methods: Occupational cohort time scales were identified and organized through simple equations of three time scales (relational triads) and the connections between these triads (time scale web). The behavior of the time scales was examined when constraints were imposed on variable ranges and interrelationships. Results: Constraints on a time scale in a triad create high correlations between the other two time scales. These correlations combine with the connections between relational triads to produce association paths. High correlation between time scales leads to ambiguity of interpretation. Conclusions: Understanding the properties of occupational cohort time scales, their relational triads, and the time scale web is helpful in understanding the origins of otherwise obscure confounding bias and ambiguity of interpretation. PMID:25647318

  10. Time Management for Directors

    ERIC Educational Resources Information Center

    Jaffe, Ellen Hofstetter

    2005-01-01

    Time management is a skill. Like any new skill, it takes time and commitment to develop. A frequent complaint of center directors is not having enough time. Most work extremely long hours and still feel they are not getting enough done. This article presents ideas on how to manage time and work smarter, not harder. These ideas are the following:

  11. Time and Teaching

    ERIC Educational Resources Information Center

    McEwan, Anna E.

    2012-01-01

    This essay invites reflection on the phenomena of time as it impacts the day-to-day life of teachers. It also explores assumptions about time and teaching in three areas: first, beliefs about the force of time and the teacher's struggle to control it; second, beliefs about the potential of time and the benefits of its passing for teachers and

  12. Time Management for Directors

    ERIC Educational Resources Information Center

    Jaffe, Ellen Hofstetter

    2005-01-01

    Time management is a skill. Like any new skill, it takes time and commitment to develop. A frequent complaint of center directors is not having enough time. Most work extremely long hours and still feel they are not getting enough done. This article presents ideas on how to manage time and work smarter, not harder. These ideas are the following:…

  13. Time and Teaching

    ERIC Educational Resources Information Center

    McEwan, Anna E.

    2012-01-01

    This essay invites reflection on the phenomena of time as it impacts the day-to-day life of teachers. It also explores assumptions about time and teaching in three areas: first, beliefs about the force of time and the teacher's struggle to control it; second, beliefs about the potential of time and the benefits of its passing for teachers and…

  14. Review of time scales. [Universal Time-Ephemeris Time-International Atomic Time

    NASA Technical Reports Server (NTRS)

    Guinot, B.

    1974-01-01

    The basic time scales are presented: International Atomic Time, Universal Time, and Universal Time (Coordinated). These scales must be maintained in order to satisfy specific requirements. It is shown how they are obtained and made available at a very high level of precision.

  15. Rhythm, Timing and the Timing of Rhythm

    PubMed Central

    Arvaniti, Amalia

    2009-01-01

    This article reviews the evidence for rhythmic categorization that has emerged on the basis of rhythm metrics, and argues that the metrics are unreliable predictors of rhythm which provide no more than a crude measure of timing. It is further argued that timing is distinct from rhythm and that equating them has led to circularity and a psychologically questionable conceptualization of rhythm in speech. It is thus proposed that research on rhythm be based on the same principles for all languages, something that does not apply to the widely accepted division of languages into stress- and syllable-timed. The hypothesis is advanced that these universal principles are grouping and prominence and evidence to support it is provided. PMID:19390230

  16. Effect of a Vocal Choice Reaction Time Task on the Kinematics of the First Recovery Step after a Sudden Underfoot Perturbation during Gait

    PubMed Central

    Kim, Hogene; Ashton-Miller, James A.

    2012-01-01

    Thirty-two healthy young adults (15 women) were tested for their ability to maintain their comfortable step pattern following an unpredictable underfoot perturbation in the presence and absence of a concurrent vocal choice reaction time task. Custom instrumented shoes were used to randomly deliver an unexpected medial or lateral forefoot perturbation that inverted the mid-foot an average of 10 degrees or everted the midfoot an average of 9 degrees during one stance phase of a gaittrial. Medial and lateral perturbations were randomized between left and right feet in 12 of 30 gait trials. The results of the repeated measures analyses of variance show that, compared to the step parameters of unperturbed gait, the administration of the unexpected underfoot perturbation did not significantly lead to alterations in the step length or width of the first recovery step. In addition, the simultaneous administration of a vocal choice reaction time task with the underfoot perturbation did not significantly affect the kinematics of the first recovery step. We conclude that in young healthy adults an unexpected 9–10 degree underfoot perturbation, with or without a vocal reaction time task, will not affect their recovery step kinematics when walking at a comfortable gait speed. PMID:22795474

  17. Effect of a vocal choice reaction time task on the kinematics of the first recovery step after a sudden underfoot perturbation during gait.

    PubMed

    Nnodim, Joseph O; Kim, Hogene; Ashton-Miller, James A

    2013-01-01

    Thirty-two healthy young adults (15 women) were tested for their ability to maintain their comfortable step pattern following an unpredictable underfoot perturbation in the presence and absence of a concurrent vocal choice reaction time task. Custom instrumented shoes were used to randomly deliver an unexpected medial or lateral forefoot perturbation that inverted the mid-foot an average of 10° or everted the midfoot an average of 9° during one stance phase of a gait trial. Medial and lateral perturbations were randomized between left and right feet in 12 of 30 gait trials. The results of the repeated measures analyses of variance show that, compared to the step parameters of unperturbed gait, the administration of the unexpected underfoot perturbation did not significantly lead to alterations in the step length or width of the first recovery step. In addition, the simultaneous administration of a vocal choice reaction time task with the underfoot perturbation did not significantly affect the kinematics of the first recovery step. We conclude that in young healthy adults an unexpected 9-10° underfoot perturbation, with or without a vocal reaction time task, will not affect their recovery step kinematics when walking at a comfortable gait speed. PMID:22795474

  18. GNSS times and UTC

    NASA Astrophysics Data System (ADS)

    Lewandowski, W.; Arias, E. F.

    2011-08-01

    Global Navigation Satellite Systems (GNSSs) use internal reference time scales: GPS Time, GLONASS Time, Galileo System Time and BeiDou System Time. Constructed from a clock ensemble, they are designed for internal system synchronization, necessary to produce a navigation solution. They are usually steered to an external stable reference time scale, for example UTC(USNO), modulo 1 s, for GPS time. To achieve safe operation of a GNSS, a system time should preferably be a uniform time scale not affected by the leap seconds of Coordinated Universal Time (UTC). But this is not compatible with international recommendations that radio broadcast time signals should conform as closely as possible to UTC. This paper describes the various approaches chosen by GNSS providers and the relation between GNSS system times and UTC in terms of numbering of seconds. Different solutions for numbering seconds do not help the GNSS interoperability. This paper also explains why, on some occasions, GNSS system times play a role of alternative time scales with the consequent risk of confusion.

  19. Physiologic time: A hypothesis

    NASA Astrophysics Data System (ADS)

    West, Damien; West, Bruce J.

    2013-06-01

    The scaling of respiratory metabolism with body size in animals is considered by many to be a fundamental law of nature. One apparent consequence of this law is the scaling of physiologic time with body size, implying that physiologic time is separate and distinct from clock time. Physiologic time is manifest in allometry relations for lifespans, cardiac cycles, blood volume circulation, respiratory cycle, along with a number of other physiologic phenomena. Herein we present a theory of physiologic time that explains the allometry relation between time and total body mass averages as entailed by the hypothesis that the fluctuations in the total body mass are described by a scaling probability density.

  20. Time Management in College.

    ERIC Educational Resources Information Center

    Cranney, A. Garr; Kirby, Alan F.

    Time management may be the most important study skill. The effects of a specific teaching technique designed to alter the time management skills of undergraduate students in a voluntary study skills course were assessed. Of the 95 subjects, 34 were enrolled in the course and were exposed to time management instruction, 31 were future course…

  1. Expectancy, Attention, and Time.

    ERIC Educational Resources Information Center

    Barnes, Ralph; Jones, Mari Riess

    2000-01-01

    Examined the influence of contextual timing manipulations on prospective time judgments through 7 experiments involving a total of 199 college students. Discusses results in terms of various stimulus-based models of prospective time judgments, including those that appeal to attentional periodicities and entrainment. (SLD)

  2. Commission 31: Time

    NASA Astrophysics Data System (ADS)

    Defraigne, Pascale; Manchester, Richard N.; Matsakis, Demetrios; Hosokawa, Mizuhiko; Leschiutta, Sigfrido; Matsakis, Demetrios; Petit, Gérard; Zao-Cheng, Zhai

    The realization and dissemination of the international time scales is the responsibility of the section on Time, Frequency and Gravimetry of the BIPM. Commission 31 supports and coordinates investigations associated with Time definitions, realizations, astronomical data relevant to atomic timekeeping, such as pulsar data. The major developments achieved during the period 2005-2008 in that domain are reported here.

  3. Pushing for Part Time.

    ERIC Educational Resources Information Center

    Geber, Beverly

    1987-01-01

    More employees are choosing to work part time. Although this trend started because of working women, some men are choosing part-time positions. Part-time employees forfeit salary and promotion potential, yet most feel the trade is fair and that they are more productive during their working hours. (CH)

  4. Time Is Money

    ERIC Educational Resources Information Center

    Oxley, Diana; Baete, Glenn

    2012-01-01

    One has heard it before: time is money, especially when it comes to adding time for instruction to the school day. When budgets are tight and relief is nowhere in sight, how can schools afford to implement a reform as costly as adding instructional time? It's a daunting task, yet current federal educational priorities tied to federal funding…

  5. Time Management for Educators.

    ERIC Educational Resources Information Center

    Burden, Paul R.

    Time management principles can help teachers become more aware of ways in which time can be used to the greatest advantage. An exploration of personal time perspectives is a step toward establishing effective patterns of behavior. Productivity may be high in the morning and low in the late afternoon, for example, and organizing some activities to…

  6. Parametric Timing Analysis

    SciTech Connect

    Vivancos, E; Healy, C; Mueller, F; Whalley, D

    2001-05-09

    Embedded systems often have real-time constraints. Traditional timing analysis statically determines the maximum execution time of a task or a program in a real-time system. These systems typically depend on the worst-case execution time of tasks in order to make static scheduling decisions so that tasks can meet their deadlines. Static determination of worst-case execution times imposes numerous restrictions on real-time programs, which include that the maximum number of iterations of each loop must be known statically. These restrictions can significantly limit the class of programs that would be suitable for a real-time embedded system. This paper describes work-in-progress that uses static timing analysis to aid in making dynamic scheduling decisions. For instance, different algorithms with varying levels of accuracy may be selected based on the algorithm's predicted worst-case execution time and the time allotted for the task. We represent the worst-case execution time of a function or a loop as a formula, where the unknown values affecting the execution time are parameterized. This parametric timing analysis produces formulas that can then be quickly evaluated at run-time so dynamic scheduling decisions can be made with little overhead. Benefits of this work include expanding the class of applications that can be used in a real-time system, improving the accuracy of dynamic scheduling decisions, and more effective utilization of system resources. This paper describes how static timing analysis can be used to aid in making dynamic scheduling decisions. The WCET of a function or a loop is represented as a formula, where the values affecting the execution time are parameterized. Such formulas can then be quickly evaluated at run-time so dynamic scheduling decisions can be made when scheduling a task or choosing algorithms within a task. Benefits of this parametric timing analysis include expanding the class of applications that can be used in a real-time system, improving the accuracy of dynamic scheduling decisions, and more effective utilization of system resources.

  7. Changes in cortical activity associated with adaptive behavior during repeated balance perturbation of unpredictable timing

    PubMed Central

    Mierau, Andreas; Hülsdünker, Thorben; Strüder, Heiko K.

    2015-01-01

    The compensation for a sudden balance perturbation, unpracticed and unpredictable in timing and magnitude is accompanied by pronounced postural instability that is suggested to be causal to falls. However, subsequent presentations of an identical perturbation are characterized by a marked decrease of the amplitude of postural reactions; a phenomenon called adaptation or habituation. This study aimed to identify cortical characteristics associated with adaptive behavior during repetitive balance perturbations based on single-trial analyses of the P1 and N1 perturbation-evoked potentials. Thirty-seven young men were exposed to ten transient balance perturbations while balancing on the dominant leg. Thirty two-channel electroencephalography (EEG), surface electromyography (EMG) of the ankle plantar flexor muscles and postural sway (i.e., Euclidean distance of the supporting platform) were recorded simultaneously. The P1 and N1 potentials were localized and the amplitude/latency was analyzed trial by trial. The best match sources for P1 and N1 potentials were located in the parietal (Brodmann area (BA) 5) and midline fronto-central cortex (BA 6), respectively. The amplitude and latency of the P1 potential remained unchanged over trials. In contrast, a significant adaptation of the N1 amplitude was observed. Similar adaptation effects were found with regard to postural sway and ankle plantarflexors EMG activity of the non-dominant (free) leg; i.e., an indicator for reduced muscular co-contraction and/or less temporary bipedal stance to regain stability. Significant but weak correlations were found between N1 amplitude and postural sway as well as EMG activity. These results highlight the important role of the midline fronto-central cortex for adaptive behavior associated with balance control. PMID:26528154

  8. When time matters.

    PubMed

    Theadore, Jason C

    2011-01-01

    The most important organizational resource is energy. The most important resource in time management is energy. Managing energy, not time, can help create encouraging time management skills and appropriate work life balance. Once a leader understands that time should be spent on things that are important instead of everything that is urgent, you can begin to develop a balance that will support your values, your family, and your organization. When leaders find meaningful ways to add a sense of purpose to their work they can personally improve themselves and their organizations. If your personal values do not align with the values of your organization you will never work with a true sense of purpose. Make the time to manage your energy. You will be surprised how much free time you find. PMID:21793462

  9. On Time Performance Pressure

    NASA Technical Reports Server (NTRS)

    Connell, Linda; Wichner, David; Jakey, Abegael

    2013-01-01

    Within many operations, the pressures for on-time performance are high. Each month, on-time statistics are reported to the Department of Transportation and made public. There is a natural tendency for employees under pressure to do their best to meet these objectives. As a result, pressure to get the job done within the allotted time may cause personnel to deviate from procedures and policies. Additionally, inadequate or unavailable resources may drive employees to work around standard processes that are seen as barriers. However, bypassing practices to enable on-time performance may affect more than the statistics. ASRS reports often highlight on-time performance pressures which may result in impact across all workgroups in an attempt to achieve on-time performance. Reporters often provide in-depth insights into their experiences which can be used by industry to identify and focus on the implementation of systemic fixes.

  10. It's About Time!

    NASA Technical Reports Server (NTRS)

    Clark, Tom

    2000-01-01

    Everything we do in VLBI is connected to time. In this contribution, we review 28 orders of magnitude of the spectrum of time ranging from a few hundred femtoseconds (i.e. one degree of phase at X-band - Pi x 10(exp -13) seconds) upwards to tens of millions of years (i.e. ten million years Pi x 10(exp 14) seconds). In this discussion, we will pay special attention to the relation between the underlying oscillator (the frequency standard that defines a clock's rate) and the time kept by the clock (which counts the oscillations of the frequency standard). We will consider two different types of time - time kept by counting an atomic frequency standard (Hydrogen Maser or Cesium), and time reckoned by the rotation of the Earth underneath the stars and sun.

  11. Time card entry system

    SciTech Connect

    Montierth, B.S.

    1996-05-01

    The Time Card Entry System was developed to interface with the DOE Headquarters Electronic Time and Attendance (ETA) system. It features pop-up window pick lists for Work Breakdown Structure Numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills US Government/OMB requirements before Timekeepers process the data at the end of the two week payroll cycle using ETA. Tours of Duty (e.g. ten hour day, four day week with Friday through Sunday off), established in the ETA system, are imported into the Time Card Entry System by the Timekeepers. An individual`s Tour of Duty establishes the basis for validation of time of day and number of hours worked per day. At the end of the two week cycle, data is exported by the Timekeepers from the Time Card Entry System into ETA data files.

  12. [Time perceptions and representations].

    PubMed

    Tordjman, S

    2015-09-01

    Representations of time and time measurements depend on subjective constructs that vary according to changes in our concepts, beliefs, societal needs and technical advances. Similarly, the past, the future and the present are subjective representations that depend on each individual's psychic time and biological time. Therefore, there is no single, one-size-fits-all time for everyone, but rather a different, subjective time for each individual. We need to acknowledge the existence of different inter-individual times but also intra-individual times, to which different functions and different rhythms are attached, depending on the system of reference. However, the construction of these time perceptions and representations is influenced by objective factors (physiological, physical and cognitive) related to neuroscience which will be presented and discussed in this article. Thus, studying representation and perception of time lies at the crossroads between neuroscience, human sciences and philosophy. Furthermore, it is possible to identify several constants among the many and various representations of time and their corresponding measures, regardless of the system of time reference. These include the notion of movements repeated in a stable rhythmic pattern involving the recurrence of the same interval of time, which enables us to define units of time of equal and invariable duration. This rhythmicity is also found at a physiological level and contributes through circadian rhythms, in particular the melatonin rhythm, to the existence of a biological time. Alterations of temporality in mental disorders will be also discussed in this article illustrated by certain developmental disorders such as autism spectrum disorders. In particular, the hypothesis will be developed that children with autism would need to create discontinuity out of continuity through stereotyped behaviors and/or interests. This discontinuity repeated at regular intervals could have been fundamentally lacking in their physiological development due to possibly altered circadian rhythms, including arhythmy and asynchrony. Time measurement, based on the repetition of discontinuity at regular intervals, involves also a spatial representation. It is our own trajectory through space-time, and thus our own motion, including the physiological process of aging, that affords us a representation of the passing of time, just as the countryside seems to be moving past us when we travel in a vehicle. Chinese and Indian societies actually have circular representations of time, and linear representations of time and its trajectory through space-time are currently a feature of Western societies. Circular time is collective time, and its metaphysical representations go beyond the life of a single individual, referring to the cyclical, or at least nonlinear, nature of time. Linear time is individual time, in that it refers to the scale of a person's lifetime, and it is physically represented by an arrow flying ineluctably from the past to the future. An intermediate concept can be proposed that acknowledges the existence of linear time involving various arrows of time corresponding to different lifespans (human, animal, plant, planet lifespans, etc.). In fact, the very notion of time would depend on the trajectory of each arrow of time, like shooting stars in the sky with different trajectory lengths which would define different time scales. The time scale of these various lifespans are very different (for example, a few decades for humans and a few days or hours for insects). It would not make sense to try to understand the passage of time experienced by an insect which may live only a few hours based on a human time scale. One hour in an insect's life cannot be compared to one experienced by a human. Yet again, it appears that there is a coexistence of different clocks based here on different lifespans. Finally, the evolution of our society focused on the present moment and choosing the cesium atom as the international reference unit of time measurement (cesium has a transition frequency of 9.192.631.77000 oscillations per second), will be questioned. We can consider that focusing on the present moment, in particular on instantaneity rather than infinity, prevents us from facing our own finitude. In conclusion, the question is raised that the current representation of time might be a means of managing our fear of death, giving us the illusion of controlling the uncontrollable, in particular the passage of time, and a means of avoiding to represent what many regard as non-representable, namely our own demise. PMID:26746317

  13. Making Time for Feedback

    ERIC Educational Resources Information Center

    Fisher, Douglas; Frey, Nancy

    2012-01-01

    Ask any teacher what he or she needs more of, and it is a good bet that time will top the list. Anything that promises to recoup a little bit of their workday time is sure to be a best seller. One overlooked time-saver is in how they use feedback. Teachers know that feedback is important for teaching and learning. Unfortunately, most secondary…

  14. Time-varying BRDFs.

    PubMed

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials. PMID:17356224

  15. Variable camshaft timing system

    SciTech Connect

    Butterfield, R.P.; Smith, F.R.

    1989-09-05

    This patent describes an improvement in a variable camshaft timing system for an internal combustion engine having intake and exhaust valves and a camshaft for each of the intake and exhaust valves, an intake sprocket and an exhaust sprocket keyed to their respective camshaft, only one of the camshafts being directly driven by an engine crankshaft, and a timing chain engaging both sprockets. The improvement comprising a single bracket carrying at least one idler sprocket engaging the timing chain, the bracket being mounted for movement to alter the timing relationship between the intake and exhaust sprockets.

  16. Time estimation in flight

    NASA Technical Reports Server (NTRS)

    Awe, Cynthia A.; Johnson, Walter W.

    1991-01-01

    Experiments were performed to determine whether edge rate and flow rate impact the perception of time during an active control task and to further examine the relationship between edge rate or flow rate and time perception. One experiment also examined the extent to which time perception is driven by: (1) the temporal structure of the world, i.e., edge rate/flow rate changes, and (2) the amount of activity involved in accomplishing a task. The second factor was varied by examining time estimations made while subjects passively viewed the simulated flight and while also actively engaged in controlling lateral craft disturbances.

  17. Intrinsic time quantum geometrodynamics

    NASA Astrophysics Data System (ADS)

    Ita, Eyo Eyo; Soo, Chopin; Yu, Hoi-Lai

    2015-08-01

    Quantum geometrodynamics with intrinsic time development and momentric variables is presented. An underlying SU(3) group structure at each spatial point regulates the theory. The intrinsic time behavior of the theory is analyzed, together with its ground state and primordial quantum fluctuations. Cotton-York potential dominates at early times when the universe was small; the ground state naturally resolves Penrose's Weyl curvature hypothesis, and thermodynamic and gravitational "arrows of time" point in the same direction. Ricci scalar potential corresponding to Einstein's general relativity emerges as a zero-point energy contribution. A new set of fundamental commutation relations without Planck's constant emerges from the unification of gravitation and quantum mechanics.

  18. Initial Sensorimotor and Cardiovascular Data Acquired from Soyuz Landings: Establishing a Functional Performance Recovery Time Constant

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Kozlovskaya, I. B.; Kofman, I. S.; Tomilovskaya, E. S.; Cerisano, J. M.; Bloomberg, J. J.; Stenger, M. B.; Platts, S. H.; Rukavishnikov, I. V.; Fomina, E. V.; Lee, S. M. C.; Wood, S. J.; Mulavara, A. P.; Feiveson, A. H.; Fisher, E. A.

    2015-01-01

    INTRODUCTION Testing of crew responses following long-duration flights has not been previously possible until a minimum of more than 24 hours after landing. As a result, it has not been possible to determine the trend of the early recovery process, nor has it been possible to accurately assess the full impact of the decrements associated with long-duration flight. To overcome these limitations, both the Russian and U.S. programs have implemented joint testing at the Soyuz landing site. This International Space Station research effort has been identified as the functional Field Test, and represents data collect on NASA, Russian, European Space Agency, and Japanese Aerospace Exploration Agency crews. RESEARCH The primary goal of this research is to determine functional abilities associated with long-duration space flight crews beginning as soon after landing as possible on the day of landing (typically within 1 to 1.5 hours). This goal has both sensorimotor and cardiovascular elements. To date, a total of 15 subjects have participated in a 'pilot' version of the full 'field test'. The full version of the 'field test' will assess functional sensorimotor measurements included hand/eye coordination, standing from a seated position (sit-to-stand), walking normally without falling, measurement of dynamic visual acuity, discriminating different forces generated with the hands (both strength and ability to judge just noticeable differences of force), standing from a prone position, coordinated walking involving tandem heel-to-toe placement (tested with eyes both closed and open), walking normally while avoiding obstacles of differing heights, and determining postural ataxia while standing (measurement of quiet stance). Sensorimotor performance has been obtained using video records, and data from body worn inertial sensors. The cardiovascular portion of the investigation has measured blood pressure and heart rate during a timed stand test in conjunction with postural ataxia testing (quiet stance sway) as well as cardiovascular responses during sensorimotor testing on all of the above measures. We have also collected motion sickness data associated with each of the postflight tests. When possible rudimentary cerebellar assessment was undertaken. In addition to the immediate post-landing collection of data, postflight data has been acquired twice more within 24 hours after landing and measurements continue until sensorimotor and cardiovascular responses have returned to preflight normative values (approximately 60 days postflight). SUMMARY The level of functional deficit observed in the crew tested to date is more severe than expected, clearly triggered by the acquisition of gravity loads immediately after landing when the demands for crew intervention in response to emergency operations will be greatest. Measureable performance parameters such as ability to perform a seat egress, recover from a fall or the ability to see clearly when walking, and related physiologic data (orthostatic responses) are required to provide an evidence base for characterizing programmatic risks and the degree of variability among crewmembers for exploration missions where the crew will be unassisted after landing. Overall, these early functional and related physiologic measurements will allow the estimation of nonlinear sensorimotor and cardiovascular recovery trends that have not been previously captured.

  19. Time Functions as Utilities

    NASA Astrophysics Data System (ADS)

    Minguzzi, E.

    2010-09-01

    Every time function on spacetime gives a (continuous) total preordering of the spacetime events which respects the notion of causal precedence. The problem of the existence of a (semi-)time function on spacetime and the problem of recovering the causal structure starting from the set of time functions are studied. It is pointed out that these problems have an analog in the field of microeconomics known as utility theory. In a chronological spacetime the semi-time functions correspond to the utilities for the chronological relation, while in a K-causal (stably causal) spacetime the time functions correspond to the utilities for the K + relation (Seifert’s relation). By exploiting this analogy, we are able to import some mathematical results, most notably Peleg’s and Levin’s theorems, to the spacetime framework. As a consequence, we prove that a K-causal (i.e. stably causal) spacetime admits a time function and that the time or temporal functions can be used to recover the K + (or Seifert) relation which indeed turns out to be the intersection of the time or temporal orderings. This result tells us in which circumstances it is possible to recover the chronological or causal relation starting from the set of time or temporal functions allowed by the spacetime. Moreover, it is proved that a chronological spacetime in which the closure of the causal relation is transitive (for instance a reflective spacetime) admits a semi-time function. Along the way a new proof avoiding smoothing techniques is given that the existence of a time function implies stable causality, and a new short proof of the equivalence between K-causality and stable causality is given which takes advantage of Levin’s theorem and smoothing techniques.

  20. Biomechanical evaluation of the relationship between postural control and body mass index.

    PubMed

    Ku, P X; Abu Osman, N A; Yusof, A; Wan Abas, W A B

    2012-06-01

    Postural stability is crucial in maintaining body balance during quiet standing, locomotion, and any activities that require a high degree of balance performance, such as participating in sports and dancing. Research has shown that there is a relationship between stability and body mass. The aims of this study were to examine the impact that two variables had on static postural control: body mass index (BMI) and gender. Eighty healthy young adults (age=21.7±1.8 yr; height=1.65±0.09 m; mass=67.5±19.0 kg) participated in the study and the static postural control was assessed using the Biodex Balance System, with a 20 Hz sampling rate in the bipedic stance (BLS) and unipedic stance (ULS) for 30s. Five test evaluations were performed for each balance test. Postural control was found to be negatively correlated with increased adiposity, as the obese BMI group performed significantly poorer than the underweight, normal weight and overweight groups during BLS and ULS tests. The underweight, normal weight and overweight groups exhibited greater anterior-posterior stability in postural control during quiet stance. In addition, female displayed a trend of having a greater postural sway than male young adults, although it was evidenced in only some BMI groups. This study revealed that BMI do have an impact on postural control during both BLS and ULS. As such, BMI and gender-specific effects should be taken into consideration when selecting individuals for different types of sporting activities, especially those that require quiet standing. PMID:22507349

  1. General principles of the measure of time: astronomical time.

    NASA Astrophysics Data System (ADS)

    Guinot, B.

    Contents: 1. Introduction: conception; definition; realization. 2. General remarks on time scales: structure of a time scale; the concepts of the measure of time; stability of time scales; notation of dates and time differences; main dates of the history of the measure of time. 3. The times of dynamical models: the mean solar time and the universal time considered as a measure of time; ephemeris time; pulsar time.

  2. Providing library services in a time of fiscal crisis: alternatives.

    PubMed Central

    Cheshier, R G

    1977-01-01

    The nature of the fiscal crisis in health science libraries in the United States is in part due to the style of management in these libraries, in part due to the lack of user identification, in part due to the lack of economically valid fees for service, and in part due to the success of the Biomedical Communications Network. These issues are discussed in terms of how they might be approached. A pragmatic stance is advocated for practitioners, the MLA, the NLM, and library schools to jointly address the questions raised. PMID:901951

  3. The metrology of time.

    PubMed

    Arias, Elisa Felicitas

    2005-09-15

    Measuring time is a continuous activity, an international and restless enterprise hidden in time laboratories spread all over the planet. The Bureau International des Poids et Mesures is charged with coordinating activities for international timekeeping and it makes use of the world's capacity to produce a remarkably stable and accurate reference time-scale. Commercial atomic clocks beating the second in national laboratories can reach a stability of one part in 10(14) over a 5 day averaging time, compelling us to research the most highly performing methods of remote clock comparison. The unit of the international time-scale is the second of the International System of Units, realized with an uncertainty of the order 10(-15) by caesium fountains. Physicists in a few time laboratories are making efforts to gain one order of magnitude in the uncertainty of the realization of the second, and more refined techniques of time and frequency transfer are in development to accompany this progress. Femtosecond comb technology will most probably contribute in the near future to enhance the definition of the second with the incorporation of optical clocks. We will explain the evolution of the measuring of time, current state-of-the-art measures and future challenges. PMID:16147510

  4. TIME CALIBRATED OSCILLOSCOPE SWEEP

    DOEpatents

    Owren, H.M.; Johnson, B.M.; Smith, V.L.

    1958-04-22

    The time calibrator of an electric signal displayed on an oscilloscope is described. In contrast to the conventional technique of using time-calibrated divisions on the face of the oscilloscope, this invention provides means for directly superimposing equal time spaced markers upon a signal displayed upon an oscilloscope. More explicitly, the present invention includes generally a generator for developing a linear saw-tooth voltage and a circuit for combining a high-frequency sinusoidal voltage of a suitable amplitude and frequency with the saw-tooth voltage to produce a resultant sweep deflection voltage having a wave shape which is substantially linear with respect to time between equal time spaced incremental plateau regions occurring once each cycle of the sinusoidal voltage. The foregoing sweep voltage when applied to the horizontal deflection plates in combination with a signal to be observed applied to the vertical deflection plates of a cathode ray oscilloscope produces an image on the viewing screen which is essentially a display of the signal to be observed with respect to time. Intensified spots, or certain other conspicuous indications corresponding to the equal time spaced plateau regions of said sweep voltage, appear superimposed upon said displayed signal, which indications are therefore suitable for direct time calibration purposes.

  5. More Recess Time, Please!

    ERIC Educational Resources Information Center

    Chang, Rong; Coward, Fanni Liu

    2015-01-01

    Students in Shanghai, China, get much more recess time than their U.S. counterparts throughout their education. As U.S. education reform efforts seek ways of raising achievement, they have begun replacing recess with academic time. The lesson from Shanghai is that this may not be the best strategy. But whether the Shanghai system of more and

  6. Part-Time Faculty.

    ERIC Educational Resources Information Center

    Clery, Suzanne B.

    2001-01-01

    This study relates information regarding the role part-time faculty members fill in colleges and universities. Data are from the U.S. Department of Education's National Survey of Postsecondary Faculty, 1999. In that year, 2 of every 5 faculty members taught on a part-time basis, and they taught nearly 40% of all classes and students that were

  7. Prisoners of Time.

    ERIC Educational Resources Information Center

    National Education Commission on Time and Learning, Washington, DC.

    The Education Council Act of 1991 (Public Law 102-62) established the National Education Commission on Time and Learning as an independent advisory body charged to do a comprehensive review of the relationship between time and learning in U.S. schools. Based on its 24-month investigation, the Commission found that American students spend an…

  8. Time and Teaching

    NASA Astrophysics Data System (ADS)

    Zielinski, Theresa Julia; Brooks, David W.; Crippen, Kent J.; March, Joe L.

    2001-06-01

    Time management is an important issue for teachers and students. This article discusses teachers' use of time from the perspective of curriculum and instruction. Average high school students spend fewer than 5 hours per week in outside-of-class study; average college students spend about 20 hours. Procrastination, often viewed in a negative light by teachers, usually pays off so well for college students that seniors become better at it than freshmen. Three suggestions for designing instruction are: test early and often; do not waste the best students' time in an effort to improve overall performance; and use engaging activities that motivate students to give of their time. The impact of computers on curricula is a double-edged sword. Time must be devoted to teaching the use of applications, but the programs reduce busywork. Will this turn out to be a simple tradeoff, or will the programs make us much more efficient so that less time is required? Will computer programs ultimately lead to an expanded criterion for expertise, thus demanding even more time to become an expert? These issues are described and suggestions for controlling time during instruction are provided.

  9. Time - A Traveler's Guide

    NASA Astrophysics Data System (ADS)

    Pickover, Clifford A.

    1999-09-01

    "Bucky Fuller thought big," Wired magazine recently noted, "Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." In his newest book, Cliff Pickover outdoes even himself, probing a mystery that has baffled mystics, philosophers, and scientists throughout history--What is the nature of time?In Time: A Traveler's Guide , Pickover takes readers to the forefront of science as he illuminates the most mysterious phenomenon in the universe--time itself. Is time travel possible? Is time real? Does it flow in one direction only? Does it have a beginning and an end? What is eternity? Pickover's book offers a stimulating blend of Chopin, philosophy, Einstein, and modern physics, spiced with diverting side-trips to such topics as the history of clocks, the nature of free will, and the reason gold glitters. Numerous diagrams ensure readers will have no trouble following along.By the time we finish this book, we understand a wide variety of scientific concepts pertaining to time. And most important, we will understand that time travel is, indeed, possible.

  10. Time for Bed Game

    MedlinePlus

    ... a Friend Who Cuts? Babysitting: Time for Bed Game KidsHealth > For Teens > Babysitting: Time for Bed Game Print A A A Text Size What Kids ... kids to bed can be tough sometimes! This game introduces children to the concept of getting enough ...

  11. Time Here, Time There, Time Everywhere: Teaching Young Children Time through Daily Routine

    ERIC Educational Resources Information Center

    Lee, Joohi; Lee, Joo Ok; Fox, Jill

    2009-01-01

    According to Piaget, 5- or 6-year-old children gradually acquire the concept of time based on events (Piaget, 1969). In his experiment of investigating children's time concepts, Piaget found that children of these ages were able to place pictures based on sequential events with some errors; the younger children made more errors. The National…

  12. Survivability Versus Time

    NASA Technical Reports Server (NTRS)

    Joyner, James J., Sr.

    2014-01-01

    Develop Survivability vs Time Model as a decision-evaluation tool to assess various emergency egress methods used at Launch Complex 39B (LC 39B) and in the Vehicle Assembly Building (VAB) on NASAs Kennedy Space Center. For each hazard scenario, develop probability distributions to address statistical uncertainty resulting in survivability plots over time and composite survivability plots encompassing multiple hazard scenarios.

  13. Task Time Tracker

    Energy Science and Technology Software Center (ESTSC)

    2013-07-24

    This client-side web app tracks the amount of time spent on arbitrary tasks. It allosw the creation of an unlimited number of arbitrarily named tasks ans via simple interactions, tracks the amount of time spent working on the drfined tasks.

  14. ZERO-TIME INDICATOR

    DOEpatents

    Sander, H.H.

    1960-08-30

    The travel time of a nuclear shock wave from its point of origin to a location can be determined accurately by an apparatus for noting and comparably recording both zerotime, as indicated by the electromagnetic transient associated with the nuclear detonation, and shock wave arrival time.

  15. More Recess Time, Please!

    ERIC Educational Resources Information Center

    Chang, Rong; Coward, Fanni Liu

    2015-01-01

    Students in Shanghai, China, get much more recess time than their U.S. counterparts throughout their education. As U.S. education reform efforts seek ways of raising achievement, they have begun replacing recess with academic time. The lesson from Shanghai is that this may not be the best strategy. But whether the Shanghai system of more and…

  16. Babies Need Tummy Time

    MedlinePlus

    ... Facts ​​​​​​​​​​​​​​​​​​​​​​​​​​​ Printer-Friendly Email Page Skip sharing on social media links Babies Need Tummy Time! Page Content Tummy Time is not only an ...

  17. Prime Time School Television.

    ERIC Educational Resources Information Center

    Ittelson, John C.

    The complete text and pictures of a slide/tape and videotape presentation explain Prime Time School Television (PTST), a non-profit organization, with emphasis on the active role of participants in utilizing prime time programs in everyday teaching-learning situations. PTST encourages teachers to recommend and use evening television programs as…

  18. Timely Warning Update

    ERIC Educational Resources Information Center

    Stafford, Dolores

    2011-01-01

    A complaint received by the Department of Education alleged that Virginia Tech violated the "timely warning" requirements of the Clery Act on April 16, 2007, by not issuing specific campus-wide alerts once senior officials knew of the immediate threat to health and safety. The complaint also alleged that the University's timely warning policy, as

  19. Time for Learning

    ERIC Educational Resources Information Center

    Johnston, J. Howard

    2009-01-01

    The amount of time allocated for learning and the way that time is used is one of the few variables that can be influenced rather directly by school leaders. Fortunately, it is also a variable that has shown consistent links to student performance. Now that schools are focused directly, and in some cases exclusively, on student achievement, there…

  20. Tips for Taming Time

    ERIC Educational Resources Information Center

    LaBelle, Sandy

    2006-01-01

    This article shares seven easy ideas to help teachers tame their time-management problems. To reduce the amount of mail that makes it to one's desk, the author suggests using the "Chicken Pox" technique to limit the number of times a piece of mail is handled. With this technique, it is not necessary to make an immediate decision regarding the…

  1. Timely Warning Update

    ERIC Educational Resources Information Center

    Stafford, Dolores

    2011-01-01

    A complaint received by the Department of Education alleged that Virginia Tech violated the "timely warning" requirements of the Clery Act on April 16, 2007, by not issuing specific campus-wide alerts once senior officials knew of the immediate threat to health and safety. The complaint also alleged that the University's timely warning policy, as…

  2. Tips for Taming Time

    ERIC Educational Resources Information Center

    LaBelle, Sandy

    2006-01-01

    This article shares seven easy ideas to help teachers tame their time-management problems. To reduce the amount of mail that makes it to one's desk, the author suggests using the "Chicken Pox" technique to limit the number of times a piece of mail is handled. With this technique, it is not necessary to make an immediate decision regarding the

  3. Time, money, and morality.

    PubMed

    Gino, Francesca; Mogilner, Cassie

    2014-02-01

    Money, a resource that absorbs much daily attention, seems to be involved in much unethical behavior, which suggests that money itself may corrupt. This research examined a way to offset such potentially deleterious effects-by focusing on time, a resource that tends to receive less attention than money but is equally ubiquitous in daily life. Across four experiments, we examined whether shifting focus onto time can salvage individuals' ethicality. We found that implicitly activating the construct of time, rather than money, leads individuals to behave more ethically by cheating less. We further found that priming time reduces cheating by making people reflect on who they are. Implications for the use of time primes in discouraging dishonesty are discussed. PMID:24317421

  4. TIMING OF SHOCK WAVES

    DOEpatents

    Tuck, J.L.

    1955-03-01

    This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

  5. The Payoff Time

    PubMed Central

    Braithwaite, R. Scott; Fiellin, David; Justice, Amy C.

    2011-01-01

    Background Practice guidelines rarely consider comorbid illness, and resulting overuse of health services may increase costs without conferring benefit. Objective To individualize a framework for inferring when patients with comorbid illness are not likely to benefit from colorectal cancer screening guidelines. Methods We modified the “payoff time” framework (the minimum time until a guideline’s cumulative benefits exceed its cumulative harms) to increase its applicability to a wide range of primary care patients. We show how it may inform colorectal (CR) cancer screening decisions for 3 typical patients in general practice for whom CR screening would be recommended by current guidelines: (1) 60-year-old man with diabetes, congestive heart failure, lung disease, stroke, and substantial frailty; (2) 60-year-old woman with diabetes and obesity, without other comorbidity or frailty; and (3) 50-year-old woman with inflammatory bowel disease. Results For patient 1, the payoff time for CR screening (minimum time until benefits exceed harms) is 7.3 years, and for patient 2, the payoff time for CR screening is 5.4 years. Evidence is insufficient to estimate the payoff time for patient 3. Because patient 1’s estimated life expectancy is 3.7 years (less than his payoff time), he is unlikely to benefit from CR screening. Because patient 2’s estimated life expectancy exceeds 10 years (greater than her payoff time), she may benefit from CR screening. Because evidence is insufficient to estimate the payoff time for patient 3, the payoff time framework does not inform decision making. Conclusion The payoff time framework may identify patients for whom particular clinical guidelines are unlikely to confer benefit, and has the potential to decrease unnecessary health care. PMID:19433991

  6. Parallel time integration software

    SciTech Connect

    2014-07-01

    This package implements an optimal-scaling multigrid solver for the (non) linear systems that arise from the discretization of problems with evolutionary behavior. Typically, solution algorithms for evolution equations are based on a time-marching approach, solving sequentially for one time step after the other. Parallelism in these traditional time-integrarion techniques is limited to spatial parallelism. However, current trends in computer architectures are leading twards system with more, but not faster. processors. Therefore, faster compute speeds must come from greater parallelism. One approach to achieve parallelism in time is with multigrid, but extending classical multigrid methods for elliptic poerators to this setting is a significant achievement. In this software, we implement a non-intrusive, optimal-scaling time-parallel method based on multigrid reduction techniques. The examples in the package demonstrate optimality of our multigrid-reduction-in-time algorithm (MGRIT) for solving a variety of parabolic equations in two and three sparial dimensions. These examples can also be used to show that MGRIT can achieve significant speedup in comparison to sequential time marching on modern architectures.

  7. Parallel time integration software

    Energy Science and Technology Software Center (ESTSC)

    2014-07-01

    This package implements an optimal-scaling multigrid solver for the (non) linear systems that arise from the discretization of problems with evolutionary behavior. Typically, solution algorithms for evolution equations are based on a time-marching approach, solving sequentially for one time step after the other. Parallelism in these traditional time-integrarion techniques is limited to spatial parallelism. However, current trends in computer architectures are leading twards system with more, but not faster. processors. Therefore, faster compute speeds mustmore » come from greater parallelism. One approach to achieve parallelism in time is with multigrid, but extending classical multigrid methods for elliptic poerators to this setting is a significant achievement. In this software, we implement a non-intrusive, optimal-scaling time-parallel method based on multigrid reduction techniques. The examples in the package demonstrate optimality of our multigrid-reduction-in-time algorithm (MGRIT) for solving a variety of parabolic equations in two and three sparial dimensions. These examples can also be used to show that MGRIT can achieve significant speedup in comparison to sequential time marching on modern architectures.« less

  8. Time synchronized video systems

    NASA Technical Reports Server (NTRS)

    Burnett, Ron

    1994-01-01

    The idea of synchronizing multiple video recordings to some type of 'range' time has been tried to varying degrees of success in the past. Combining this requirement with existing time code standards (SMPTE) and the new innovations in desktop multimedia however, have afforded an opportunity to increase the flexibility and usefulness of such efforts without adding costs over the traditional data recording and reduction systems. The concept described can use IRIG, GPS or a battery backed internal clock as the master time source. By converting that time source to Vertical Interval Time Code or Longitudinal Time Code, both in accordance with the SMPTE standards, the user will obtain a tape that contains machine/computer readable time code suitable for use with editing equipment that is available off-the-shelf. Accuracy on playback is then determined by the playback system chosen by the user. Accuracies of +/- 2 frames are common among inexpensive systems and complete frame accuracy is more a matter of the users' budget than the capability of the recording system.

  9. Digital time delay

    DOEpatents

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay provides a first output signal at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits latch the high resolution data to form a first synchronizing data set. A selected time interval has been preset to internal counters and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses count down the counters to generate an internal pulse delayed by an internal which is functionally related to the preset time interval. A second LCD corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD to generate a second set of synchronizing data which is complementary with the first set of synchronizing data for presentation to logic circuits. The logic circuits further delay the internal output signal with the internal pulses. The final delayed output signal thereafter enables the output pulse generator to produce the desired output pulse at the preset time delay interval following input of the trigger pulse.

  10. Time Asymmetric Quantum Mechanics

    NASA Astrophysics Data System (ADS)

    Bohm, Arno R.; Gadella, Manuel; Kielanowski, Piotr

    2011-09-01

    The meaning of time asymmetry in quantum physics is discussed. On the basis of a mathematical theorem, the Stone-von Neumann theorem, the solutions of the dynamical equations, the Schrödinger equation (1) for states or the Heisenberg equation (6a) for observables are given by a unitary group. Dirac kets require the concept of a RHS (rigged Hilbert space) of Schwartz functions; for this kind of RHS a mathematical theorem also leads to time symmetric group evolution. Scattering theory suggests to distinguish mathematically between states (defined by a preparation apparatus) and observables (defined by a registration apparatus (detector)). If one requires that scattering resonances of width Γ and exponentially decaying states of lifetime τ=h/Γ should be the same physical entities (for which there is sufficient evidence) one is led to a pair of RHS's of Hardy functions and connected with it, to a semigroup time evolution t0≤t<∞, with the puzzling result that there is a quantum mechanical beginning of time, just like the big bang time for the universe, when it was a quantum system. The decay of quasi-stable particles is used to illustrate this quantum mechanical time asymmetry. From the analysis of these processes, we show that the properties of rigged Hilbert spaces of Hardy functions are suitable for a formulation of time asymmetry in quantum mechanics.

  11. The Time Series Toolbox

    NASA Astrophysics Data System (ADS)

    Božić, Bojan; Havlik, Denis

    2010-05-01

    Many applications commonly used in sensor service networks operate on the same type of data repeatedly over time. This kind of data is most naturally represented in the form of "time series". In its simplest form, a time series may consist of a single floating point number (e.g. temperature), that is recorded at regular intervals. More complex forms of time series include time series of complex observations (e.g. aggregations of related measurements, spectra, 2D coverages/images, ...), and time series recorded at irregular intervals. In addition, the time series may contain meta-information describing e.g. the provenance, uncertainty, and reliability of observations. The Time Series Toolbox (TS Toolbox) provides a set of software components and application programming interfaces that simplify recording, storage, processing and publishing of time series. This includes (1) "data connector" components implementing access to data using various protocols and data formats; (2) core components interfacing with the connector components and providing specific additional functionalities like data processing or caching; and (3) front-end components implementing interface functionality (user interfaces or software interfaces). The functionalities implemented by TS Toolbox components provide application developers with higher-level building blocks than typical general purpose libraries, and allow rapid development of fully fledged applications. The TS Toolbox also includes example applications that can be either used as they are, or as a basis for developing more complex applications. The TS-Toolbox, which was initially developed by the Austrian Institute of Technology in the scope of SANY "Sensors Anywhere", is written in Java, published under the terms of the GPL, and available for download on the SANY web site.

  12. VARIABLE TIME DELAY MEANS

    DOEpatents

    Clemensen, R.E.

    1959-11-01

    An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

  13. Time, Temporality, Now

    NASA Astrophysics Data System (ADS)

    Atmanspacher, Harald; Ruhnau, Eva

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

  14. Screen time and children

    MedlinePlus

    ... watching TV, working on a computer, or playing video games. Screen time is sedentary activity, meaning you are ... over. Suggest other activities, such as family board games, puzzles, ... active. Be a good role model as a parent. Decrease your own ...

  15. Timing control system

    NASA Technical Reports Server (NTRS)

    Wiker, Gordon A. (Inventor); Wells, Jr., George H. (Inventor)

    1989-01-01

    A timing control system is disclosed which is particularly useful in connection with simulated mortar shells. Special circuitry is provided to assure that the shell does not overshoot, but rather detonates early in case of an improper condition; this ensures that ground personnel will not be harmed by a delayed detonation. The system responds to an externally applied frequency control code which is configured to avoid any confusion between different control modes. A premature detonation routine is entered in case an improper time-setting signal is entered, or if the shell is launched before completion of the time-setting sequence. Special provisions are also made for very early launch situations and improper detonator connections. An alternate abort mode is provided to discharge the internal power supply without a detonation in a manner that can be externally monitored, thereby providing a mechanism for non-destructive testing. The abort mode also accelerates the timing function for rapid testing.

  16. Timing Control System

    NASA Technical Reports Server (NTRS)

    Wiker, Gordon A. (Inventor); Wells, George H., Jr. (Inventor)

    1987-01-01

    A timing control system is disclosed which is particularly useful in connection with simulated mortar shells. Special circuitry is provided to assure that the shell does not over shoot, but rather detonates early in case of an improper condition; this ensures that ground personnel will not be harmed by a delayed detonation. The system responds to an externally applied frequency control code which is configured to avoid any confusion between different control modes. A premature detonation routine is entered in case an improper time-setting signal is entered, or if the shell is launched before completion of the time-setting sequence. Special provisions are also made for very early launch situations and improper detonator connections. An alternate abort mode is provided to discharge the internal power supply without a detonation in a manner that can be externally monitored, thereby providing a mechanism for non-destructive testing. The abort mode also accelerates the timing function for rapid testing.

  17. Angles, Time, and Proportion

    ERIC Educational Resources Information Center

    Pagni, David L.

    2005-01-01

    This article describes an investigation making connections between the time on an analog clock and the angle between the minute hand and the hour hand. It was posed by a middle school mathematics teacher. (Contains 8 tables and 6 figures.)

  18. Drug Retention Times

    SciTech Connect

    Center for Human Reliability Studies

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user

  19. Drug Retention Times

    SciTech Connect

    Center for Human Reliability Studies

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user.

  20. Time to Go Local!

    MedlinePlus

    ... Bar Home Current Issue Past Issues Time to Go Local! Past Issues / Winter 2007 Table of Contents ... MedlinePlus.gov health topic pages, you will find "Go Local" links that take you to information about ...

  1. Managing Time and Tasks.

    ERIC Educational Resources Information Center

    Handy, Alice Evans; Yucht, Alice H.

    1993-01-01

    Includes two articles that discuss time management and mail management strategies for librarians. Highlights include identifying personal work styles; planning and prioritizing; using calendars and computers; reexamining traffic patterns; delegating; and sorting and handling mail. (Contains eight references.) (LRW)

  2. Imagining Deep Time (Invited)

    NASA Astrophysics Data System (ADS)

    Talasek, J.

    2013-12-01

    Imagining Deep Time '...the mind seemed to grow giddy by looking so far into the abyss of time.' John Playfair (1748 -1819), scientist and mathematician "Man cannot afford to conceive of nature and exclude himself." Emmit Gowin, photographer 'A person would have to take themselves out of the human context to begin to think in terms of geologic time. They would have to think like a rock.' Terry Falke, photographer The term Deep Time refers to the vastness of the geological time scale. First conceived in the 18th century, the development of this perspective on time has been pieced together like a jigsaw puzzle of information and observations drawn from the study of the earth's structure and discovered fossilized flora and fauna. Deep time may possibly be the greatest contribution made by the discipline of geology forever impacting our perception of earth and our relationship to it. How do we grasp such vast concepts as deep time which relates to the origins of the earth or cosmic time which relates to the origins of the universe - concepts that exist far beyond the realm of human experience? Further more how do we communicate this? The ability to visualize is a powerful tool of discovery and communication for the scientist and it is part and parcel of the work of visual artists. The scientific process provides evidence yet it is imagination on the part of the scientists and artists alike that is needed to interpret that information. This exhibition represents an area where both rational and intuitive thinking come together to explore this question of how we relate to the vastness of time. The answer suggested by the combination of art work assembled here suggests that we do so through a combination of visual metaphors (cycles, circles, arrows, trajectories) and visual evidence (rock formations, strata, fossils of fauna and flora) while being mediated through various technologies. One provides factual and empirical evidence while the other provides a way of grasping and relating to a vast concept on a personal level. This exhibition explores the usefulness as well as the limitations of the visualization of deep time.

  3. Time Scales: Terrestrial

    NASA Astrophysics Data System (ADS)

    Petit, G.; Murdin, P.

    2000-11-01

    Terrestrial time is at present derived from atomic clocks. The SI second, the unit of time of the international system of units, has been defined since 1967 in terms of a hyperfine transition of the cesium atom and the best primary frequency standards now realize it with a relative uncertainty of a few parts in 1015, which makes it the most accurately measurable physical quantity. INTERNATIONAL A...

  4. Commission 31: Time

    NASA Astrophysics Data System (ADS)

    Manchester, Richard; Hosokawa, Mizuhiko; Defraigne, Pascale; Arias, Felicitas; Zhang, ShouGang; Tuckey, Philip; Zharov, Vladimir

    2012-04-01

    IAU Commission 31 ``Time'' is part of Division I of the IAU. It currently has 103 members, a net increase of about 15% over the triennium, and 9 Consultants. The Commission web page is: www.atnf.csiro.au/iau-comm31/. It maintains a current membership list, with links to the IAU membership database, links to past and up-coming meetings related to Time and links to relevant websites and documents.

  5. Time, action, and consciousness.

    PubMed

    Cleeremans, Axel; Sarrazin, Jean-Christophe

    2007-04-01

    Time plays a central role in consciousness, at different levels and in different aspects of information processing. Subliminal perception experiments demonstrate that stimuli presented too briefly to enter conscious awareness are nevertheless processed to some extent. Implicit learning, implicit memory, and conditioning studies suggest that the extent to which memory traces are available for verbal report and for cognitive control is likewise dependent on the time available for processing during acquisition. Differences in the time available for processing also determine not only the extent to which one becomes conscious of action, but also provides the basis for making attributions of authorship to experienced acts. In this paper, we offer a brief overview of these different findings and suggest that they can all be understood based on the fact that consciousness takes time. From this perspective, the availability of representations to conscious awareness depends on the quality of these representations - the extent to which they are strong, stable in time, and distinctive. High-quality representations occur when processes of global competition have had sufficient time to operate so as to make the system settle into the best possible interpretation of the input. Such processes implement global constraint satisfaction and critically depend on reentrant processing, through which representations can be further enriched by high-level constraints. We discuss these ideas in light of current theories of consciousness, emphasizing the fact that consciousness should be viewed as a process rather than as a static property associated with some states and not with others. PMID:17346837

  6. Time Card Entry System

    Energy Science and Technology Software Center (ESTSC)

    1996-05-07

    The Time Card Entry System was developed for the Department of Enegy, Idaho Operations Office (DOE-ID) to interface with the DOE headquarters (DOE-HQ) Electronic Time and Attendance (ETA) system for payroll. It features pop-up window pick lists for Work Breakdown Structure numbers and Hour Codes and has extensive processing that ensures that time and attendance reported by the employee fulfills U.S. Government/OMB requirements before Timekeepers process the data at the end of the two weekmore » payroll cycle using ETA. A tour of duty profile (e.g., ten hour day, four day week with Sunday, friday and Saturday off), previously established in the ETA system, is imported into the Time Card Entry System by the timekeepers. An individual''s profile establishes the basis for validation of time of day and number of hours worked per day. At the end of the two cycle, data is exported by the timekeepers from the Time Card Entry System into ETA files.« less

  7. Time-Distance Helioseismology

    NASA Technical Reports Server (NTRS)

    Duvall, Thomas L., Jr.

    2010-01-01

    Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the characteristic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

  8. Fossils, rocks, and time

    USGS Publications Warehouse

    Edwards, Lucy E.; Pojeta, John

    1999-01-01

    We study our Earth for many reasons: to find water to drink or oil to run our cars or coal to heat our homes, to know where to expect earthquakes or landslides or floods, and to try to understand our natural surroundings. Earth is constantly changing--nothing on its surface is truly permanent. Rocks that are now on top of a mountain may once have been at the bottom of the sea. Thus, to understand the world we live on, we must add the dimension of time. We must study Earth's history. When we talk about recorded history, time is measured in years, centuries, and tens of centuries. When we talk about Earth history, time is measured in millions and billions of years. Time is an everyday part of our lives. We keep track of time with a marvelous invention, the calendar, which is based on the movements of Earth in space. One spin of Earth on its axis is a day, and one trip around the Sun is a year. The modern calendar is a great achievement, developed over many thousands of years as theory and technology improved. People who study Earth's history also use a type of calendar, called the geologic time scale. It looks very different from the familiar calendar. In some ways, it is more like a book, and the rocks are its pages. Some of the pages are torn or missing, and the pages are not numbered, but geology gives us the tools to help us read this book.

  9. Fossils, rocks, and time

    USGS Publications Warehouse

    Edwards, Lucy E.; Pojeta, John, Jr.

    1993-01-01

    We study out Earth for many reasons: to find water to drink or oil to run our cars or coal to heat our homes, to know where to expect earthquakes or landslides or floods, and to try to understand our natural surroundings. Earth is constantly changing--nothing on its surface is truly permanent. Rocks that are not on top of a mountain may once have been on the bottom of the sea. Thus, to understand the world we live on, we must add the dimension of time. We must study Earth's history. When we talk about recorded history, time is measured in years, centuries, and tens of centuries. When we talk about Earth history, time is measured in millions and billions of years. Time is an everyday part of our lives. We keep track of time with a marvelous invention, the calendar, which is based on the movements of the Earth in space. One spin of Earth on its axis is a day, and one trip around the sun is a year. The modern calendar is a great achievement, developed over many thousands of years as theory and technology improved. People who study Earth's history also use a type of calendar, called the geologic time scale. It looks very different from the familiar calendar. In some ways, it is more like a book, and the rocks are its pages. Some of the pages are torn or missing, and the pages are not numbered, but geology gives us the tools to help us read this book.

  10. Time-domain imaging

    NASA Technical Reports Server (NTRS)

    Tolliver, C. L.

    1989-01-01

    The quest for the highest resolution microwave imaging and principle of time-domain imaging has been the primary motivation for recent developments in time-domain techniques. With the present technology, fast time varying signals can now be measured and recorded both in magnitude and in-phase. It has also enhanced our ability to extract relevant details concerning the scattering object. In the past, the interface of object geometry or shape for scattered signals has received substantial attention in radar technology. Various scattering theories were proposed to develop analytical solutions to this problem. Furthermore, the random inversion, frequency swept holography, and the synthetic radar imaging, have two things in common: (1) the physical optic far-field approximation, and (2) the utilization of channels as an extra physical dimension, were also advanced. Despite the inherent vectorial nature of electromagnetic waves, these scalar treatments have brought forth some promising results in practice with notable examples in subsurface and structure sounding. The development of time-domain techniques are studied through the theoretical aspects as well as experimental verification. The use of time-domain imaging for space robotic vision applications has been suggested.

  11. Future Coordinated Universal Time

    NASA Astrophysics Data System (ADS)

    McCarthy, Dennis D.

    Coordinated Universal Time (UTC), created by adjusting International Atomic Time (TAI) by the appropriate number of leap seconds, is the uniform time scale that is the basis of most civil timekeeping in the world. The concept of a leap second was introduced to ensure that UTC would not differ by more than 0.9 seconds from UT1, the time determined by the rotation of the Earth. The principal reason for this was to meet the requirements of celestial navigation. However, with the proliferation in the use of satellite navigation, it is appropriate to reconsider this historical position. In view of emerging problems with the current definition of UTC in navigation and communications, user dissatisfaction with leap seconds is beginning to surface. Even with accurate estimates of the deceleration of the Earth's rotation there remain significant variations in the Earth's rate of rotation, which prevent the prediction of leap seconds beyond a few months in advance. The inability to predict leap seconds coupled with the growing urgency for a uniform time scale without discontinuities make it appropriate to examine the future definition of UTC.

  12. Discrete-Time Goldfishing

    NASA Astrophysics Data System (ADS)

    Calogero, Francesco

    2011-08-01

    The original continuous-time ''goldfish'' dynamical system is characterized by two neat formulas, the first of which provides the N Newtonian equations of motion of this dynamical system, while the second provides the solution of the corresponding initial-value problem. Several other, more general, solvable dynamical systems ''of goldfish type'' have been identified over time, featuring, in the right-hand (''forces'') side of their Newtonian equations of motion, in addition to other contributions, a velocity-dependent term such as that appearing in the right-hand side of the first formula mentioned above. The solvable character of these models allows detailed analyses of their behavior, which in some cases is quite remarkable (for instance isochronous or asymptotically isochronous). In this paper we introduce and discuss various discrete-time dynamical systems, which are as well solvable, which also display interesting behaviors (including isochrony and asymptotic isochrony) and which reduce to dynamical systems of goldfish type in the limit when the discrete-time independent variable l=0,1,2,... becomes the standard continuous-time independent variable t, 0≤t<∞.

  13. Time and moral judgment.

    PubMed

    Suter, Renata S; Hertwig, Ralph

    2011-06-01

    Do moral judgments hinge on the time available to render them? According to a recent dual-process model of moral judgment, moral dilemmas that engage emotional processes are likely to result in fast deontological gut reactions. In contrast, consequentialist responses that tot up lives saved and lost in response to such dilemmas would require cognitive control to override the initial response. Cognitive control, however, takes time. In two experiments, we manipulated the time available to arrive at moral judgments in two ways: by allotting a fixed short or large amount of time, and by nudging people to answer swiftly or to deliberate thoroughly. We found that faster responses indeed lead to more deontological responses among those moral dilemmas in which the killing of one to save many necessitates manhandling an innocent person and in which this action is depicted as a means to an end. Thus, our results are the first demonstration that inhibiting cognitive control through manipulations of time alters moral judgments. PMID:21354557

  14. Time rate collision matrix

    SciTech Connect

    Stoenescu, M.L.; Smith, T.M.

    1980-02-01

    The collision integral terms in Boltzmann equation are reformulated numerically leading to the substitution of the multiple integrals with a multiplicative matrix of the two colliding species velocity distribution functions which varies with the differential collision cross section. A matrix of lower rank may be constructed when one of the distribution functions is specified, in which case the matrix elements represent kinetic transition probabilities in the velocity space and the multiplication of the time rate collision matrix with the unknown velocity distribution function expresses the time rate of change of the distribution. The collision matrix may be used to describe the time evolution of systems in nonequilibrium conditions, to evaluate the rate of momentum and energy transfer between given species, or to generate validity criteria for linearized kinetic equations.

  15. Real-time radiography

    SciTech Connect

    Bossi, R.H.; Oien, C.T.

    1981-02-26

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components.

  16. Real-Time Simulation

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Coryphaeus Software, founded in 1989 by former NASA electronic engineer Steve Lakowske, creates real-time 3D software. Designer's Workbench, the company flagship product, is a modeling and simulation tool for the development of both static and dynamic 3D databases. Other products soon followed. Activation, specifically designed for game developers, allows developers to play and test the 3D games before they commit to a target platform. Game publishers can shorten development time and prove the "playability" of the title, maximizing their chances of introducing a smash hit. Another product, EasyT, lets users create massive, realistic representation of Earth terrains that can be viewed and traversed in real time. Finally, EasyScene software control the actions among interactive objects within a virtual world. Coryphaeus products are used on Silican Graphics workstation and supercomputers to simulate real-world performance in synthetic environments. Customers include aerospace, aviation, architectural and engineering firms, game developers, and the entertainment industry.

  17. Agency, time, and causality

    PubMed Central

    Widlok, Thomas

    2014-01-01

    Cognitive Scientists interested in causal cognition increasingly search for evidence from non-Western Educational Industrial Rich Democratic people but find only very few cross-cultural studies that specifically target causal cognition. This article suggests how information about causality can be retrieved from ethnographic monographs, specifically from ethnographies that discuss agency and concepts of time. Many apparent cultural differences with regard to causal cognition dissolve when cultural extensions of agency and personhood to non-humans are taken into account. At the same time considerable variability remains when we include notions of time, linearity and sequence. The article focuses on ethnographic case studies from Africa but provides a more general perspective on the role of ethnography in research on the diversity and universality of causal cognition. PMID:25414683

  18. Timing is everything

    PubMed Central

    Faulk, Christopher

    2011-01-01

    Environmental influence on developmental plasticity impacts a wide diversity of animal life from insects to humans. We now understand the epigenetic basis for many of these altered phenotypes. The five environmental factors of nutrition, behavior, stress, toxins and stochasticity work individually and in concert to affect the developing epigenome. During early embryogenesis, epigenetic marks, such as DNA methylation, are reset at specific times. Two waves of global demethylation and reestablishment of methylation frame the sensitive times for early environmental influences and will be the focus of this review. Gene transcription, translation and post-translational modification of chromatin remodeling complexes are three mechanisms affected by developmental exposure to environmental factors. To illustrate how changes in the early environment profoundly affect these mechanisms, we provide examples throughout the animal kingdom. Herein we review the history, time points and mechanisms of epigenetic gene-environment interaction. PMID:21636976

  19. Time and language.

    PubMed

    Scharf, J H

    1982-01-01

    It is very interesting question whether time if a priori in mankind's thinking or whether it is a category which results from experience. Each human being has a memory so that he is able to distinguish between the past and the present, but not every language has a word expressing the common idea of time. In hunting and gathering populations such as Bushmen and Yumbri no one can state his own age. In chronobiology, the most important zeitgebers are the sun and the moon. Certain peasant peoples, such as the Santals and Mundas in India, even today use the same word to express sun, Sun-God, daylight, day, day-time, and hour. The first generalized idea of "time" seems to have arisen in the civilization of Old Mesopotamia. While the general meaning was still unknown to Sumerian, Accadian priest-astronomers presumably created the conception by generalization of the (Sumerian) foreign word itu(d) "mouth" and its mingling with the Accadian ittu(m) "sign (as an eclipse, monstrous birth, etc.), term, moment". We find the same root in the Etruscan itus "ides" from which it came as a loan-word into Latin (idus "ides"). Newton's term duratio can be found in earliest Iranian as yav- "yoke" and Vedic Indian as yugam "yoke" (i.e., a "bound" time). Some remarks are made concerning mankind's earliest chronobiological thinking where menstruation serves as a model. West African Kwa languages (predominantly Ewe), Old Indian, and early-classical chinese are evaluated. A brief survey is given of prehistoric peoples' migrations in terms of languages. The presentation concludes with an attempt to define time as an abstraction of abstractions, a fussy set (of ideas and definitions) in terms of post-classical set theory. PMID:7129063

  20. Optimal Switching Time

    NASA Astrophysics Data System (ADS)

    Klich, Israel; Levitov, Leonid

    2005-03-01

    We discuss the noise produced in the process of switching mesoscopic conductors between two noiseless states: perfectly connected and disconnected, in the presence of a bias voltage V. We show that there are two main contributions to the noise: a switching noise logarithmic in the time of observation T, and a quantum shot noise accumulated during the process of switching and proportional to V, this leads to a minimization problem for the optimal switching time. Switching noise is expected to be a fundamental parameter in nano-circuits. We also discuss the relation of this result to an estimation of entangelment entropy of a Fermi sea.

  1. Laboratory Turnaround Time

    PubMed Central

    Hawkins, Robert C

    2007-01-01

    Turnaround time (TAT) is one of the most noticeable signs of laboratory service and is often used as a key performance indicator of laboratory performance. This review summarises the literature regarding laboratory TAT, focusing on the different definitions, measures, expectations, published data, associations with clinical outcomes and approaches to improve TAT. It aims to provide a consolidated source of benchmarking data useful to the laboratory in setting TAT goals and to encourage introduction of TAT monitoring for continuous quality improvement. A 90% completion time (sample registration to result reporting) of <60 minutes for common laboratory tests is suggested as an initial goal for acceptable TAT. PMID:18392122

  2. Predicting chaotic time series

    SciTech Connect

    Farmer, J.D.; Sidorowich, J.J.

    1987-08-24

    We present a forecasting technique for chaotic data. After embedding a time series in a state space using delay coordinates, we ''learn'' the induced nonlinear mapping using local approximation. This allows us to make short-term predictions of the future behavior of a time series, using information based only on past values. We present an error estimate for this technique, and demonstrate its effectiveness by applying it to several examples, including data from the Mackey-Glass delay differential equation, Rayleigh-Benard convection, and Taylor-Couette flow.

  3. Time, Chance, and Reduction

    NASA Astrophysics Data System (ADS)

    Ernst, Gerhard; Httemann, Andreas

    2010-01-01

    List of contributors; 1. Introduction Gerhard Ernst and Andreas Htteman; Part I. The Arrows of Time: 2. Does a low-entropy constraint prevent us from influencing the past? Mathias Frisch; 3. The part hypothesis meets gravity Craig Callender; 4. Quantum gravity and the arrow of time Claus Kiefer; Part II. Probability and Chance: 5. The natural-range conception of probability Jacob Rosenthal; 6. Probability in Boltzmannian statistical mechanics Roman Frigg; 7. Humean mechanics versus a metaphysics of powers Michael Esfeld; Part III. Reduction: 8. The crystallisation of Clausius's phenomenological thermodynamics C. Ulises Moulines; 9. Reduction and renormalization Robert W. Batterman; 10. Irreversibility in stochastic dynamics Jos Uffink; Index.

  4. Times for interplanetary trips

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1976-01-01

    The times required to travel to the various planets at an acceleration of one g are calculated. Surrounding gravitational fields are neglected except for a relatively short distance near take-off or landing. The orbit consists of an essentially straight line with the thrust directed toward the destination up to the halfway point, but in the opposite direction for the remainder so that the velocity is zero on arrival. A table lists the approximate times required, and also the maximum velocities acquired in light units v/c for the various planets.

  5. Science of Time

    NASA Astrophysics Data System (ADS)

    Vedavyas

    A Multi-disciplinary Research into the Chronologies of Ancient Nations -- like the Vedas of India Rishies, the Chaldeans, Babylonians, Egyptians and the Chinese. Which traces how the "Measurement of Time" -- which began with the observations of sunrise and Sunset, Full-Moons, eclipses, the movement of stars and the Discovery of the Zodiac that starry pathway of sun in his annual Cycle of the 12-Zodiacal months, the Measurement of Time by planetary Cycles the Discovery of Astronomy and Symbolic or Kabalistic Astrology of the Bible's Old Testament; the Epics of Babylonians and 'Cosmic Cycles' of Chaldeans and Egyptians also the Ancient "Four Yugas" or Hindu Vedic Cycles.

  6. Video time encoding machines.

    PubMed

    Lazar, Aurel A; Pnevmatikakis, Eftychios A

    2011-03-01

    We investigate architectures for time encoding and time decoding of visual stimuli such as natural and synthetic video streams (movies, animation). The architecture for time encoding is akin to models of the early visual system. It consists of a bank of filters in cascade with single-input multi-output neural circuits. Neuron firing is based on either a threshold-and-fire or an integrate-and-fire spiking mechanism with feedback. We show that analog information is represented by the neural circuits as projections on a set of band-limited functions determined by the spike sequence. Under Nyquist-type and frame conditions, the encoded signal can be recovered from these projections with arbitrary precision. For the video time encoding machine architecture, we demonstrate that band-limited video streams of finite energy can be faithfully recovered from the spike trains and provide a stable algorithm for perfect recovery. The key condition for recovery calls for the number of neurons in the population to be above a threshold value. PMID:21296708

  7. Time for Reading?

    ERIC Educational Resources Information Center

    Fowler, William R.

    1989-01-01

    Reading for pleasure and enlightenment is a critical, and endangered, element in a well-informed citizenry. As a basis for intellectual growth, reading is threatened by media misuse and lack of encouragement of recreational reading. Solutions include emphasis on integrated skills, improved time allocation, and cooperation among parents, teachers,…

  8. Time Series Database

    Energy Science and Technology Software Center (ESTSC)

    2007-11-02

    TSDB is a Python module for storing large volumes of time series data. TSDB stores data in binary files indexed by a timestamp. Aggregation functions (such as rate, sum, avg, etc.) can be performed on the data, but data is never discarded. TSDB is presently best suited for SNMP data but new data types are easily added.

  9. Time and Moral Judgment

    ERIC Educational Resources Information Center

    Suter, Renata S.; Hertwig, Ralph

    2011-01-01

    Do moral judgments hinge on the time available to render them? According to a recent dual-process model of moral judgment, moral dilemmas that engage emotional processes are likely to result in fast deontological gut reactions. In contrast, consequentialist responses that tot up lives saved and lost in response to such dilemmas would require…

  10. The SIM Time Network.

    PubMed

    Lombardi, Michael A; Novick, Andrew N; Lopez R, J Mauricio; Jimenez, Francisco; de Carlos Lopez, Eduardo; Boulanger, Jean-Simon; Pelletier, Raymond; de Carvalho, Ricardo J; Solis, Raul; Sanchez, Harold; Quevedo, Carlos Andres; Pascoe, Gregory; Perez, Daniel; Bances, Eduardo; Trigo, Leonardo; Masi, Victor; Postigo, Henry; Questelles, Anthony; Gittens, Anselm

    2011-01-01

    The Sistema Interamericano de Metrologia (SIM) is a regional metrology organization (RMO) whose members are the national metrology institutes (NMIs) located in the 34 nations of the Organization of American States (OAS). The SIM/OAS region extends throughout North, Central, and South America and the Caribbean Islands. About half of the SIM NMIs maintain national standards of time and frequency and must participate in international comparisons in order to establish metrological traceability to the International System (SI) of units. The SIM time network (SIMTN) was developed as a practical, cost effective, and technically sound way to automate these comparisons. The SIMTN continuously compares the time standards of SIM NMIs and produces measurement results in near real-time by utilizing the Internet and the Global Positioning System (GPS). Fifteen SIM NMIs have joined the network as of December 2010. This paper provides a brief overview of SIM and a technical description of the SIMTN. It presents international comparison results and examines the measurement uncertainties. It also discusses the metrological benefits that the network provides to its participants. PMID:26989584

  11. Where in Time?

    ERIC Educational Resources Information Center

    Pecore, John; Sacks, David

    2005-01-01

    In this article, the authors describe an activity developed to assist students with constructing their own understanding of Earth's history and provide questions to help teach the geologic time scale. The lesson is aligned to the following National Science Education Standards: Science as Inquiry, Earth's History, and Nature of Science. While

  12. A Walk through Time.

    ERIC Educational Resources Information Center

    Renfroe, Mark; Letendre, Wanda

    1996-01-01

    Describes a seventh-grade class project where students constructed a "time tunnel" (a walk-through display with models and exhibits illustrating various themes and eras). Beginning modestly, the tunnel grew over seven years to include 11 different display scenes. Discusses the construction of the project and benefits to the school. (MJP)

  13. Decay Time of Cathodoluminescence

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2009-01-01

    Simple measurements of the decay time of cathodoluminescence are described. Cathodoluminescence is used in many devices, including computer monitors, oscilloscopes, radar displays and television tubes. The experimental setup is simple and easy to build. Two oscilloscopes, a function generator, and a fast photodiode are needed for the experiments.

  14. Bootstrapping Time Dilation Decoherence

    NASA Astrophysics Data System (ADS)

    Gooding, Cisco; Unruh, William G.

    2015-10-01

    We present a general relativistic model of a spherical shell of matter with a perfect fluid on its surface coupled to an internal oscillator, which generalizes a model recently introduced by the authors to construct a self-gravitating interferometer (Gooding and Unruh in Phys Rev D 90:044071, 2014). The internal oscillator evolution is defined with respect to the local proper time of the shell, allowing the oscillator to serve as a local clock that ticks differently depending on the shell's position and momentum. A Hamiltonian reduction is performed on the system, and an approximate quantum description is given to the reduced phase space. If we focus only on the external dynamics, we must trace out the clock degree of freedom, and this results in a form of intrinsic decoherence that shares some features with a proposed "universal" decoherence mechanism attributed to gravitational time dilation (Pikovski et al in Nat Phys, 2015). We note that the proposed decoherence remains present in the (gravity-free) limit of flat spacetime, emphasizing that the effect can be attributed entirely to proper time differences, and thus is not necessarily related to gravity. Whereas the effect described in (Pikovski et al in Nat Phys, 2015) vanishes in the absence of an external gravitational field, our approach bootstraps the gravitational contribution to the time dilation decoherence by including self-interaction, yielding a fundamentally gravitational intrinsic decoherence effect.

  15. This Time It's Personal

    ERIC Educational Resources Information Center

    Demski, Jennifer

    2012-01-01

    Educators have known for some time now that a one-size-fits-all approach to learning does not lead to the level of student engagement and academic success that schools strive to achieve. In their search for a more customized approach to delivering instruction, they've explored project-based learning, addressed different learning styles, and…

  16. It's Time to Reassess.

    ERIC Educational Resources Information Center

    Van Groningen, Tom

    In light of recent changes in social and cultural values and the effects these changes have had on higher education, community college leaders must take the time to reassess the mission and function of the California community colleges. Shifts away from traditional values toward an increased emphasis on personal needs and aspirations may explain…

  17. Timing and throttle linkage

    SciTech Connect

    Wenstadt, T.D.; Hagen, M.W.

    1986-11-18

    This patent describes a timing throttle control for a spark ignition internal combustion engine having a fuel/air mixing device and a spark timing device. The control comprises a first pivot on the engine, a first lever mounted on the pivot and including a cam slot having a first portion which has a substantially uniform radius about the pivot and a second portion which has a non-constant radii about the first pivot. A control means is connected to the first lever to actuate the first lever about the first pivot, a second pivot on the engine in non-parallel relation to the first pivot. A second lever is mounted on the second pivot and operative to control the timing of the spark timing device, a spherical cam follower is mounted on the second lever and engaged with the cam slot. A third lever is mounted on the third pivot and operatively connected to the fuel/air mixing device. A link interconnects the first level and the third lever.

  18. A Moment in Time

    ERIC Educational Resources Information Center

    Lonergan, David

    2013-01-01

    There is a growing literature on the disappearance of the traditional model of higher education. Fewer courses are taught now than was the case just a few years ago by a full-time, permanent instructor in a single location, to students that the instructor has actually met in person. Another very real threat to the range of education is the growing

  19. Time reversal communication system

    DOEpatents

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  20. Lessons: Math. It's Time.

    ERIC Educational Resources Information Center

    Krech, Bob

    2000-01-01

    Describes how to use a one-handed clock for teaching time telling: make a one-handed clock (hour hand only); discuss clock history; have students use approximate language to describe where the hour hand is; have students practice with their own clocks; introduce the minute hand; have students compare the clocks; and have students add minute hands

  1. This Time It's Personal

    ERIC Educational Resources Information Center

    Demski, Jennifer

    2012-01-01

    Educators have known for some time now that a one-size-fits-all approach to learning does not lead to the level of student engagement and academic success that schools strive to achieve. In their search for a more customized approach to delivering instruction, they've explored project-based learning, addressed different learning styles, and

  2. The First Time

    ERIC Educational Resources Information Center

    Black, Beth

    2011-01-01

    In this article, the author narrates her experience of meeting a Montessori kid for the first time and shares the characteristics she observed in Montessori students. The author was working as director of academic resources in university housing at the University of Wisconsin-Madison and met Jason, a pre-med sophomore who was the resident…

  3. A Moment in Time

    ERIC Educational Resources Information Center

    Lonergan, David

    2013-01-01

    There is a growing literature on the disappearance of the traditional model of higher education. Fewer courses are taught now than was the case just a few years ago by a full-time, permanent instructor in a single location, to students that the instructor has actually met in person. Another very real threat to the range of education is the growing…

  4. Leadership in Challenging Times

    ERIC Educational Resources Information Center

    City, Elizabeth A.

    2013-01-01

    In spite of tough financial times, resourceful school leaders devise ways to overcome challenges and improve education. To do this, they make strategic use of the resources they have. And they also cultivate learning communities. In this article, Elizabeth A. City describes how school leaders can make more strategic use of three essential

  5. HAWC Timing Calibration

    NASA Astrophysics Data System (ADS)

    Kelley-Hoskins, Nathan; Huentemeyer, Petra; Matthews, John; Dingus, Brenda; HAWC Collaboration

    2011-04-01

    The High-Altitude Water Cherenkov (HAWC) Experiment is a second-generation high sensitivity gamma-ray and cosmic-ray detector that builds on the experience and technology of the Milagro observatory. HAWC utilizes the water Cherenkov technique to measure extensive air showers. Instead of a pond filled with water (as in Milagro), an array of closely packed water tanks with 3 PMTs each is used. The cosmic ray's direction will be reconstructed using the times when the PMTs in each tank are triggered. Therefore, the timing calibration will be crucial for reaching an angular resolution as low as 0.1 degrees. We propose to use a laser calibration system, patterned after the calibration system in Milagro. The HAWC optical calibration system uses less than 1 ns laser light pulses, directed into two optical fiber networks. Each network will use optical fan-outs and switches to direct light to specific tanks. The first network is used to measure the light transit time out to each pair of tanks, and the second network sends light to each tank, calibrating each tank's 3 PMTs. Time slewing corrections will be made using neutral density filters to control the light intensity over 4 orders of magnitude. This system is envisioned to run both continuously at a low rate, or at a high rate with many intensity levels. In this presentation, we present the design of the calibration system and first measurements of its performance.

  6. The SIM Time Network

    PubMed Central

    Lombardi, Michael A.; Novick, Andrew N.; Lopez R, J. Mauricio; Jimenez, Francisco; de Carlos Lopez, Eduardo; Boulanger, Jean-Simon; Pelletier, Raymond; de Carvalho, Ricardo J.; Solis, Raul; Sanchez, Harold; Quevedo, Carlos Andres; Pascoe, Gregory; Perez, Daniel; Bances, Eduardo; Trigo, Leonardo; Masi, Victor; Postigo, Henry; Questelles, Anthony; Gittens, Anselm

    2011-01-01

    The Sistema Interamericano de Metrologia (SIM) is a regional metrology organization (RMO) whose members are the national metrology institutes (NMIs) located in the 34 nations of the Organization of American States (OAS). The SIM/OAS region extends throughout North, Central, and South America and the Caribbean Islands. About half of the SIM NMIs maintain national standards of time and frequency and must participate in international comparisons in order to establish metrological traceability to the International System (SI) of units. The SIM time network (SIMTN) was developed as a practical, cost effective, and technically sound way to automate these comparisons. The SIMTN continuously compares the time standards of SIM NMIs and produces measurement results in near real-time by utilizing the Internet and the Global Positioning System (GPS). Fifteen SIM NMIs have joined the network as of December 2010. This paper provides a brief overview of SIM and a technical description of the SIMTN. It presents international comparison results and examines the measurement uncertainties. It also discusses the metrological benefits that the network provides to its participants. PMID:26989584

  7. Leadership in Challenging Times

    ERIC Educational Resources Information Center

    City, Elizabeth A.

    2013-01-01

    In spite of tough financial times, resourceful school leaders devise ways to overcome challenges and improve education. To do this, they make strategic use of the resources they have. And they also cultivate learning communities. In this article, Elizabeth A. City describes how school leaders can make more strategic use of three essential…

  8. Decay Time of Cathodoluminescence

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2009-01-01

    Simple measurements of the decay time of cathodoluminescence are described. Cathodoluminescence is used in many devices, including computer monitors, oscilloscopes, radar displays and television tubes. The experimental setup is simple and easy to build. Two oscilloscopes, a function generator, and a fast photodiode are needed for the experiments.…

  9. Part-Time Employment.

    ERIC Educational Resources Information Center

    Guichard, Gus; And Others

    The employment of community college instructors on a part-time basis provides the opportunity for students to study under outstanding instructors whose primary employment may be in industry or in other postsecondary institutions and permits colleges to respond better to community needs with the financial resources available to them. Along with…

  10. Equal Time for Women.

    ERIC Educational Resources Information Center

    Kolata, Gina

    1984-01-01

    Examines social influences which discourage women from pursuing studies in computer science, including monopoly of computer time by boys at the high school level, sexual harassment in college, movies, and computer games. Describes some initial efforts to encourage females of all ages to study computer science. (JM)

  11. Time-Encoded Imagers.

    SciTech Connect

    Marleau, Peter; Brubaker, Erik

    2014-11-01

    This report provides a short overview of the DNN R&D funded project, Time-Encoded Imagers. The project began in FY11 and concluded in FY14. The Project Description below provides the overall motivation and objectives for the project as well as a summary of programmatic direction. It is followed by a short description of each task and the resulting deliverables.

  12. Asymmetry through time dependency

    NASA Astrophysics Data System (ADS)

    Mantzaris, Alexander V.; Higham, Desmond J.

    2016-03-01

    Given a single network of interactions, asymmetry arises when the links are directed. For example, if protein A upregulates protein B and protein B upregulates protein C, then (in the absence of any further relationships between them) A may affect C but not vice versa. This type of imbalance is reflected in the associated adjacency matrix, which will lack symmetry. A different type of imbalance can arise when interactions appear and disappear over time. If A meets B today and B meets C tomorrow, then (in the absence of any further relationships between them) A may pass a message or disease to C, but not vice versa. Hence, even when each interaction is a two-way exchange, the effect of time ordering can introduce asymmetry. This observation is very closely related to the fact that matrix multiplication is not commutative. In this work, we describe a method that has been designed to reveal asymmetry in static networks and show how it may be combined with a measure that summarizes the potential information flow between nodes in the temporal case. This results in a new method that quantifies the asymmetry arising through time ordering. We show by example that the new tool can be used to visualize and quantify the amount of asymmetry caused by the arrow of time.

  13. TIME PROJECT: AN OVERVIEW

    EPA Science Inventory

    The TIME (Temporally Integrated Monitoring of Ecosystems) project has been in the conceptual and design stage for approximately two years. elays in implementation have allowed careful attention to many aspects of network design not usually covered prior to field implementation. h...

  14. Video Time Encoding Machines

    PubMed Central

    Lazar, Aurel A.; Pnevmatikakis, Eftychios A.

    2013-01-01

    We investigate architectures for time encoding and time decoding of visual stimuli such as natural and synthetic video streams (movies, animation). The architecture for time encoding is akin to models of the early visual system. It consists of a bank of filters in cascade with single-input multi-output neural circuits. Neuron firing is based on either a threshold-and-fire or an integrate-and-fire spiking mechanism with feedback. We show that analog information is represented by the neural circuits as projections on a set of band-limited functions determined by the spike sequence. Under Nyquist-type and frame conditions, the encoded signal can be recovered from these projections with arbitrary precision. For the video time encoding machine architecture, we demonstrate that band-limited video streams of finite energy can be faithfully recovered from the spike trains and provide a stable algorithm for perfect recovery. The key condition for recovery calls for the number of neurons in the population to be above a threshold value. PMID:21296708

  15. Time and Moral Judgment

    ERIC Educational Resources Information Center

    Suter, Renata S.; Hertwig, Ralph

    2011-01-01

    Do moral judgments hinge on the time available to render them? According to a recent dual-process model of moral judgment, moral dilemmas that engage emotional processes are likely to result in fast deontological gut reactions. In contrast, consequentialist responses that tot up lives saved and lost in response to such dilemmas would require

  16. Proper time physics.

    NASA Astrophysics Data System (ADS)

    Montanus, J. M. C.

    1999-12-01

    It is argued that Minkowski's implementation of distances is not unique. An alternative implementation is proposed. If Einstein's prescription for light speed measurements is applied to the new implementation, the special theory of relativity is recovered. Yet, the present model is based on a spacetime with a preferred frame of reference. A clock at rest with respect to the preferred frame is used for the parameterisation of events. The proper time of an object is taken as its fourth coordinate. Distances are measured according to the Euclidean metric. In the present approach mass is a constant of motion. A mass is ascribed to photons and neutrinos. Mechanics, gravitational dynamics and electrodynamics are reformulated in close correspondence with classical physics. The new gravitational dynamics leads to the correct predictions for the deflection of light and the precession of perihelia, while it is based on a flat spacetime. A new conservation law emerges from the new mechanics: the conservation of proper time momentum. It allows for a mechanical explanation for Compton scattering and pair annihilation. In the new electrodynamics the electric field is proportional to the proper time velocity. Intriguing consequences are discussed. The equation of motion for the proper time momentum turns out to be very powerful. In the classical limit it reduces to the classical law for the conservation of energy. The Bohr model for the atom is given a new explanation. As is discussed briefly, the present approach gives a new notion to matters as energy, the structure of spacetime, antiparticles and the arrow of time. In fact, the contents of the present paper will have extreme implications for the foundations of physics in general.

  17. Stop wasting valuable time.

    PubMed

    Mankins, Michael C

    2004-09-01

    Companies routinely squander their most precious resource--the time of their top executives. In the typical company, senior executives meet to discuss strategy for only three hours a month. And that time is poorly spent in diffuse discussions never even meant to result in any decision. The price of misused executive time is high. Delayed strategic decisions lead to overlooked waste and high costs, harmful cost reductions, missed new product and business development opportunities, and poor long-term investments. But a few deceptively simple changes in the way top management teams set agendas and structure team meetings can make an enormous difference in their effectiveness. Efficient companies use seven techniques to make the most of the time their top executives spend together. They keep strategy meetings separate from meetings focused on operations. They explore issues through written communications before they meet, so that meeting time is used solely for reaching decisions. In setting agendas, they rank the importance of each item according to its potential to create value for the company. They seek to get issues not only on, but also off, the agenda quickly, keeping to a clear implementation timetable. They make sure they have considered all viable alternatives before deciding a course of action. They use a common language and methodology for reaching decisions. And they insist that, once a decision is made, they stick to it--that there be no more debate or mere grudging compliance. Once leadership teams get the basics right, they can make more fundamental changes in the way they work together. Strategy making can be transformed from a series of fragmented and unproductive events into a streamlined, effective, and continuing management dialogue. In companies that have done this, management meetings aren't a necessary evil; they're a source of real competitive advantage. PMID:15449855

  18. Time Dependent Volcano Deformation

    NASA Astrophysics Data System (ADS)

    Segall, P.

    2006-12-01

    Time varying deformation can arise due to changes in magma pressure, evolution of the source geometry (e.g., dike propagation), or time dependent response of the surrounding crust. It is important to understand the signatures of these processes in order to distinguish between them. Here I explore time dependent surface deformation due to viscoelastic and poroelastic relaxation of the crust surrounding simplified magma chambers. Viscoelastic deformation is considered in a shell surrounding a spherical magma chamber in a half-space (as analyzed numerically by Newman et al, 2001). The full space solution for a Maxwell rheology was given by Dragoni and Magnanensi (PEPI, 1989). An approximate half-space solution is simply constructed following the approach of McTigue (JGR, 1987) as long as the outer radius R2 is small compared to the depth d. The surface displacements are scaled, time-dependent versions of the Mogi solution in an elastic half-space. For a step increase in magma pressure (other source histories are also simply constructed) uz (ρ, z=0, t) = (1 - ν) p0 R13 / μ d2 [ e-t/tR + R23 / R13 ( 1 - e-t/tR ) ] 1 / (1 + ρ2)3/2 where R1 is the magma chamber radius, ρ is the normalized radial distance from the center of the source, and the characteristic relaxation time is tR = (3η/μ)(1-ν)/(1+ν)(R2/R1)3, where η is viscosity and μ is shear modulus. The post-intrusion displacements scale with (R2/R1)3 - 1 and can be significant. For example, a viscoelastic shell of only 20% the radius of the magma chamber leads to time dependent displacements that are 70% of the instantaneous elastic displacements. An approximate fully time-dependent solution for a cylindrical (plane strain) magma chamber in a homogeneous poro-elastic half-space is constructed as the superposition of the solution due to an expanding chamber in a full plane, and distributed shear and normal loads on a poroelastic half-space. The full-space solution is pure shear and thus induces no change in pore pressure. Consequently, the distributed loads necessary to cancel the imposed tractions on the free surface are time invariant. The surface displacements due to the applied surface loads are found using displacement potentials in the Fourier-Laplace domain; the Laplace transforms are inverted analytically. The vertical velocity resulting from the instantaneous inflation of the magma chamber is 2 μ vz(z=0,t) = β (1-ν) [ N? - i sgn(k) T? ] √ c/π t e- c k2 t - c k √1-β e-β c k2 terfc( √c (1-β) k2 t) where k is horizontal wavenumber, c is hydraulic diffusivity, √{1-β} = 1-2γ2, γ2 = νu - ν/1-ν , νu is the undrained Poisson's ratio, and N? and T? are the Fourier transformed normal N and shear T tractions acting on the plane z = 0, N = (μ Δ V/π ) (x2- d2) /(d2 + x2)2, T = (2μ Δ V/ π )dx/(d2 + x2)2. The displacement immediately above the source increases monotonically, however the flanking regions subside for some time following the initial elastic uplift before further uplifting. This arises because pore fluid flows from the flanking region to the center of uplift. The final uplift is identical to the initial elastic uplift but increased by a factor of νu-ν.

  19. Time Varying Feature Data

    NASA Astrophysics Data System (ADS)

    Echterhoff, J.; Simonis, I.; Atkinson, R.

    2012-04-01

    The infrastructure to gather, store and access information about our environment is improving and growing rapidly. The increasing amount of information allows us to get a better understanding of the current state of our environment, historical processes and to simulate and predict the future state of the environment. Finer grained spatial and temporal data and more reliable communications make it easier to model dynamic states and ephemeral features. The exchange of information within and across geospatial domains is facilitated through the use of harmonized information models. The Observations & Measurements (O&M) developed through OGC and standardised by ISO is an example of such a cross-domain information model. It is used in many domains, including meteorology, hydrology as well as the emergency management. O&M enables harmonized representation of common metadata that belong to the act of determining the state of a feature property, whether by sensors, simulations or humans. In addition to the resulting feature property value, information such as the result quality but especially the time that the result applies to the feature property can be represented. Temporal metadata is critical to modelling past and future states of a feature. The features, and the semantics of each property, are defined in domain specific Application Schema using the General Feature Model (GFM) from ISO 19109 and usually encoded following ISO 19136. However, at the moment these standards provide only limited support for the representation and handling of time varying feature data. Features like rivers, wildfires or gas plumes have a defined state - for example geographic extent - at any given point in time. To keep track of changes, a more complex model for example using time-series coverages is required. Furthermore, the representation and management of feature property value changes via the service interfaces defined by OGC and ISO - namely: WFS and WCS - would be rather complex. Keeping track of feature property value corrections or even feature (state change) cancellations for auditing purposes is also not easy to achieve. The aviation domain has strong requirements to represent and manage the state of aeronautical features through time. Being able to efficiently encode and manage feature state changes, keeping track of all changes for auditing purposes and being able to determine the future state of an aeronautical feature as currently known to the system are vital for aeronautical applications. In order to support these requirements, the Aeronautical Information Exchange Model (AIXM) which has been developed by the aviation domain is based on the so called AIXM Temporality Model (AIXM-TM). The AIXM-TM defines various rules for modeling, representing and handling the state of aeronautical features through time. This is a promising approach that can be incorporated into the GFM so that ultimately the modeling and management of time varying feature data is supported in an interoperable and harmonized way in all geospatial domains. This presentation gives an introduction to the main concepts of the AIXM-TM. It also shows how the GFM can be extended to support time varying feature data. Finally, the relationship of O&M and time varying features is discussed.

  20. Researching participant recruitment times.

    PubMed

    O'Brien, Rachel; Black, Polly

    2015-11-01

    Conducting research in emergency departments is relatively new, and there are a number of ethical and practical challenges to recruiting patients in these settings. In 2008, the Emergency Medicine Research Group Edinburgh (EMERGE) was set up at the Royal Infirmary of Edinburgh emergency department to support researchers and encourage the growth of research in emergency medicine. As part of a review of their working methods, the group's clinical nurse researchers undertook a small study to identify participant recruitment times. The results showed a significant difference between perceived and actual recruitment times, which has implications for planning staff numbers and budgets. This article describes the evaluation process and methods of data collection, and discusses the results. PMID:26542924

  1. Tevatron injection timing

    SciTech Connect

    Saritepe, S.; Annala, G.

    1993-06-01

    Bunched beam transfer from one accelerator to another requires coordination and synchronization of many ramped devices. During collider operation timing issues are more complicated since one has to switch from proton injection devices to antiproton injection devices. Proton and antiproton transfers are clearly distinct sequences since protons and antiprotons circulate in opposite directions in the Main Ring (MR) and in the Tevatron. The time bumps are different, the kicker firing delays are different, the kickers and lambertson magnets are different, etc. Antiprotons are too precious to be used for tuning purposes, therefore protons are transferred from the Tevatron back into the Main Ring, tracing the path of antiprotons backwards. This tuning operation is called ``reverse injection.`` Previously, the reverse injection was handled in one supercycle. One batch of uncoalesced bunches was injected into the Tevatron and ejected after 40 seconds. Then the orbit closure was performed in the MR. In the new scheme the lambertson magnets have to be moved and separator polarities have to be switched, activities that cannot be completed in one supercycle. Therefore, the reverse injection sequence was changed. This involved the redefinition of TVBS clock event $D8 as MRBS $D8 thus making it possible to inject 6 proton batches (or coalesced bunches) and eject them one at a time on command, performing orbit closure each time in the MR. Injection devices are clock event driven. The TCLK is used as the reference clock. Certain TCLK events are triggered by the MR beam synchronized clock (MRBS) events. Some delays are measured in terms of MRBS ticks and MR revolutions. See Appendix A for a brief description of the beam synchronized clocks.

  2. Hard Times Hit Schools

    ERIC Educational Resources Information Center

    McNeil, Michele

    2008-01-01

    Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,…

  3. Music in Galileo's Time

    NASA Astrophysics Data System (ADS)

    Petrobelli, P.

    2011-06-01

    Claudio Monteverdi appears as the key personality of the music in Galileo's time. His revolution in format and function of the musical language-from an essentially edonistic creation of purely sonorous images to a musical language consciously "expressive" of the content of the words on which it is based-is similar in character to the influential innovations in scientific thinking operated by Galileo.

  4. Real Time Baseball Database

    NASA Astrophysics Data System (ADS)

    Fukue, Yasuhiro

    The author describes the system outline, features and operations of "Nikkan Sports Realtime Basaball Database" which was developed and operated by Nikkan Sports Shimbun, K. K. The system enables to input numerical data of professional baseball games as they proceed simultaneously, and execute data updating at realtime, just-in-time. Other than serving as supporting tool for prepareing newspapers it is also available for broadcasting media, general users through NTT dial Q2 and others.

  5. Running out of time.

    PubMed

    Zigmond, Jessica

    2013-10-21

    After a glitch-plagued rollout of state and federal healthcare exchanges, officials are scrambling to fix the marketplaces before a crucial mid-November deadline. If the problems can't be fixed in time for consumers to get enrolled by Jan. 1, it will hand ammunition to Republicans who want to delay the ACA's individual mandate. "If you can't enroll people, how can you penalize them?" asks Tom Miller of the American Enterprise Institute. PMID:24340853

  6. Time at the beginning

    SciTech Connect

    Michael S. Turner

    2002-10-11

    Age consistency for the Universe today has been an important cosmological test. Even more powerful consistency tests at times as early as 10{sup -32} sec lie ahead in the precision era of cosmology. I outline tests based upon cosmic microwave background (CMB) anisotropy, big-bang nucleosynthesis (BBN), particle dark matter, phase transitions, and inflation. The ultimate cosmic timescale--the fate of the Universe--will be in doubt until the mystery of the dark energy is unraveled.

  7. NASA PERT time II

    NASA Technical Reports Server (NTRS)

    Bainbridge, R. C.; Funicelli, F.; Hirsch, D. J.; Pallat, E. A.; Ryan, E.; Walker, J. D.; Bremmer, H.

    1980-01-01

    Program Evaulation and Review Technique (PERT) is disciplined management technique involving computer processing. NASA PERT Time 11 gives project manager insight into current and future project development and forewarns of potential problems. Program utilizes modular technique. Module is "fragnet"; once aspects of project are described in terms of fragnets, control network is automatically generated. Program is written in FORTRAN IV and OS Assembler for batch execution and has been implemented on IBM 370.

  8. Gravity, Time, and Lagrangians

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2010-01-01

    Feynman mentioned to us that he understood a topic in physics if he could explain it to a college freshman, a high school student, or a dinner guest. Here we will discuss two topics that took us a while to get to that level. One is the relationship between gravity and time. The other is the minus sign that appears in the Lagrangian. (Why would one…

  9. Improving Hospital Discharge Time

    PubMed Central

    El-Eid, Ghada R.; Kaddoum, Roland; Tamim, Hani; Hitti, Eveline A.

    2015-01-01

    Abstract Delays in discharging patients can impact hospital and emergency department (ED) throughput. The discharge process is complex and involves setting specific challenges that limit generalizability of solutions. The aim of this study was to assess the effectiveness of using Six Sigma methods to improve the patient discharge process. This is a quantitative pre and post-intervention study. Three hundred and eighty-six bed tertiary care hospital. A series of Six Sigma driven interventions over a 10-month period. The primary outcome was discharge time (time from discharge order to patient leaving the room). Secondary outcome measures included percent of patients whose discharge order was written before noon, percent of patients leaving the room by noon, hospital length of stay (LOS), and LOS of admitted ED patients. Discharge time decreased by 22.7% from 2.2 hours during the preintervention period to 1.7 hours post-intervention (P < 0.001). A greater proportion of patients left their room before noon in the postintervention period (P < 0.001), though there was no statistical difference in before noon discharge. Hospital LOS dropped from 3.4 to 3.1 days postintervention (P < 0.001). ED mean LOS of patients admitted to the hospital was significantly lower in the postintervention period (6.9 ± 7.8 vs 5.9 ± 7.7 hours; P < 0.001). Six Sigma methodology can be an effective change management tool to improve discharge time. The focus of institutions aspiring to tackle delays in the discharge process should be on adopting the core principles of Six Sigma rather than specific interventions that may be institution-specific. PMID:25816029

  10. Timing, Remembering, and Discrimination

    ERIC Educational Resources Information Center

    Sargisson, Rebecca J.; White, K. Geoffrey

    2007-01-01

    Four pigeons were first trained in a timing procedure. In one condition, each trial began with the presentation of an X on the center key, followed by a delay (short or long), after which two side keys were lit. If the delay was short, pecks to the red side key were reinforced. If the delay was long, pecks to the green side key were reinforced. In…

  11. Time processing in dyscalculia.

    PubMed

    Cappelletti, Marinella; Freeman, Elliot D; Butterworth, Brian L

    2011-01-01

    To test whether atypical number development may affect other types of quantity processing, we investigated temporal discrimination in adults with developmental dyscalculia (DD). This also allowed us to test whether number and time may be sub-served by a common quantity system or decision mechanisms: if they do, both should be impaired in dyscalculia, but if number and time are distinct they should dissociate. Participants judged which of two successively presented horizontal lines was longer in duration, the first line being preceded by either a small or a large number prime ("1" or "9") or by a neutral symbol ("#"), or in a third task participants decided which of two Arabic numbers (either "1," "5," "9") lasted longer. Results showed that (i) DD's temporal discriminability was normal as long as numbers were not part of the experimental design, even as task-irrelevant stimuli; however (ii) task-irrelevant numbers dramatically disrupted DD's temporal discriminability the more their salience increased, though the actual magnitude of the numbers had no effect; in contrast (iii) controls' time perception was robust to the presence of numbers but modulated by numerical quantity: therefore small number primes or numerical stimuli seemed to make durations appear shorter than veridical, but longer for larger numerical prime or numerical stimuli. This study is the first to show spared temporal discrimination - a dimension of continuous quantity - in a population with a congenital number impairment. Our data reinforce the idea of a partially shared quantity system across numerical and temporal dimensions, which supports both dissociations and interactions among dimensions; however, they suggest that impaired number in DD is unlikely to originate from systems initially dedicated to continuous quantity processing like time. PMID:22194731

  12. The sun in time

    NASA Technical Reports Server (NTRS)

    Sonett, Charles P. (Editor); Giampapa, Mark S. (Editor); Matthews, Mildred S. (Editor)

    1991-01-01

    Various papers on solar science are presented. The optics considered include: variability of solar irradiance, sunspot number, solar diameter, and solar wind properties; theory of luminosity and radius variations; standard solar models; the sun and the IMF; variations of cosmic-ray flux with time; accelerated particles in solar flares; solar cosmic ray fluxes during the last 10 million yrs; solar neutrinos and solar history; time variations of Be-10 and solar activity; solar and terrestrial components of the atmospheric C-14 variation spectrum; solar flare heavy-ion tracks in extraterrestrial objects. Also addressed are: the faint young sun problem; atmospheric responses to solar irradiation; quaternary glaciations; solar-terrestrial relationships in recent sea sediments; magnetic history of the sun; pre- and main-sequence evolution of solar activity; magnetic activity in pre-main-sequence stars; classical T Tauri stars; relict magnetism of meteorites; luminosity variability of solar-type stars; evolution of angular momentum in solar-mass stars; time evolution of magnetic fields on solarlike stars.

  13. Real-Time PCR

    NASA Astrophysics Data System (ADS)

    Evrard, A.; Boulle, N.; Lutfalla, G. S.

    Over the past few years there has been a considerable development of DNA amplification by polymerase chain reaction (PCR), and real-time PCR has now superseded conventional PCR techniques in many areas, e.g., the quantification of nucleic acids and genotyping. This new approach is based on the detection and quantification of a fluorescent signal proportional to the amount of amplicons generated by PCR. Real-time detection is achieved by coupling a thermocycler with a fluorimeter. This chapter discusses the general principles of quantitative real-time PCR, the different steps involved in implementing the technique, and some examples of applications in medicine. The polymerase chain reaction (PCR) provides a way of obtaining a large number of copies of a double-stranded DNA fragment of known sequence. This DNA amplification technique, developed in 1985 by K. Mullis (Cetus Corporation), saw a spectacular development over the space of a few years, revolutionising the methods used up to then in molecular biology. Indeed, PCR has many applications, such as the detection of small amounts of DNA, cloning, and quantitative analysis (assaying), each of which will be discussed further below.

  14. Time Reversal Violation

    SciTech Connect

    Quinn, H; /SLAC

    2009-01-27

    This talk briefly reviews three types of time-asymmetry in physics, which I classify as universal, macroscopic and microscopic. Most of the talk is focused on the latter, namely the violation of T-reversal invariance in particle physics theories. In sum tests of microscopic T-invariance, or observations of its violation, are limited by the fact that, while we can measure many processes, only in very few cases can we construct a matched pair of process and inverse process and observe it with sufficient sensitivity to make a test. In both the cases discussed here we can achieve an observable T violation making use of flavor tagging, and in the second case also using the quantum properties of an antisymmetric coherent state of two B mesons to construct a CP-tag. Both these tagging properties depend only on very general properties of the flavor and/or CP quantum numbers and so provide model independent tests for T-invariance violations. The microscopic laws of physics are very close to T-symmetric. There are small effects that give CP- and T-violating processes in three-generation-probing weak decays. Where a T-violating observable can be constructed we see the relationships between T-violation and CP-violation expected in a CPT conserving theory. These microscopic effects are unrelated to the 'arrow of time' that is defined by increasing entropy, or in the time direction defined by the expansion of our Universe.

  15. Generalized Canonical Time Warping.

    PubMed

    Zhou, Feng; De la Torre, Fernando

    2016-02-01

    Temporal alignment of human motion has been of recent interest due to its applications in animation, tele-rehabilitation and activity recognition. This paper presents generalized canonical time warping (GCTW), an extension of dynamic time warping (DTW) and canonical correlation analysis (CCA) for temporally aligning multi-modal sequences from multiple subjects performing similar activities. GCTW extends previous work on DTW and CCA in several ways: (1) it combines CCA with DTW to align multi-modal data (e.g., video and motion capture data); (2) it extends DTW by using a linear combination of monotonic functions to represent the warping path, providing a more flexible temporal warp. Unlike exact DTW, which has quadratic complexity, we propose a linear time algorithm to minimize GCTW. (3) GCTW allows simultaneous alignment of multiple sequences. Experimental results on aligning multi-modal data, facial expressions, motion capture data and video illustrate the benefits of GCTW. The code is available at http://humansensing.cs.cmu.edu/ctw. PMID:26761734

  16. Funding Full-Time Study through Part-Time Work

    ERIC Educational Resources Information Center

    Richardson, Mark; Evans, Carl; Gbadamosi, Gbolahan

    2009-01-01

    Full-time students engaged in part-time studies have been a subject of increasing academic attention. This study extends work in this area by examining: the extent to which full-time undergraduate students undertake part-time employment, the reasons for working whilst studying full-time and the extent to which students relate their part-time

  17. Commission 31: Time

    NASA Astrophysics Data System (ADS)

    Matsakis, Demetrios; Defraigne, Pascale; Hosokawa, M.; Leschiutta, S.; Petit, G.; Zhai, Z.-C.

    2007-03-01

    The most intensely discussed and controversial issue in time keeping has been the proposal before the International Telecommunications Union (ITU) to redefine Coordinated Universal Time (UTC) so as to replace leap seconds by leap hours. Should this proposal be adopted, the practice of inserting leap seconds would cease after a specific date. Should the Earth's rotation continue to de-accelerate at its historical rate, the next discontinuity in UTC would be an hour inserted several centuries from now. Advocates of this proposal cite the need to synchronize satellite and other systems, such as GPS, Galileo, and GLONASS, which did not exist and were not envisioned when the current system was adopted. They note that leap second insertions can be and have been incorrectly implemented or accounted for. Such errors have to date had localized impact, but they could cause serious mishaps involving loss of life. For example, some GPS receivers have been known to fail simply because there was no leap second after a long enough interval, other GPS receivers failed because the leap second information was broadcast more than three months in advance, and some commercial software used for internet time-transfer Network Time Protocol (NTP) could either discard all data received after a leap second or interpret it as a frequency change. The ambiguity associated with the extra second could also disrupt financial accounting and certain forms of encryption. Those opposed to the proposal question the need for a change, and also point out the costs of adjusting to the proposed change and its inconvenience to amateur astronomers and others who rely upon astronomical calculations published in advance. Reports have been circulated that the cost of checking and correcting software to accommodate the new definition of UTC would be many millions of dollars for some systems. In October 2005 American Astronomical Society asked the ITU for a year's time to study the issue. This commission has supported the efforts of the IAU' s Committee on the Leap Second to make an informed recommendation, and anticipates considerable discussion at the IAU's 26th General Assembly in 2006.

  18. Age associated differences in postural equilibrium control: a comparison between EQscore and minimum time to contact (TTC(min)).

    PubMed

    Forth, Katharine E; Metter, E Jeffrey; Paloski, William H

    2007-01-01

    Increased postural instability and the subsequent elevation in fall incidence with increasing age are important contributors for hip fractures and developing frailty. When testing for such instability, most studies characterize balance in terms of center-of-mass (COM) deviation from a finite point, the "equilibrium point", located at the center of a subject's stance. For example, the clinically accepted equilibrium score (EQscore) represents instability as the maximum peak-to-peak sway about the "equilibrium point". An alternative theory views balance as being controlled within a "stability margin" in which all corrective actions are based on the time to contact (TTC) of the body's COM with that margin. This study examines the differences offered by evaluating balance control using the EQscore and TTC approach across several age groups and sessions. Consenting subjects from the Baltimore Longitudinal Study of Aging were recruited (N=155) from each age decade (20s-80s) who were generally healthy and free from neurological diagnoses. Results showed TTC tests detected significant variations in eyes open versus eyes closed testing that were unpredictable by EQscore. Further, TTC produced differences in age-related stability threats not seen using EQscore. The TTC data also provided a discriminating difference between subjects who fell in the difficult tests and those who maintained posture. Overall, these data suggest EQscore might not sufficiently account for dynamic control components the body may be using to maintain balance. TTC may offer a more accurate estimate of postural stability (functional ability) than EQscore based on its inclusion of a velocity component to detect dynamic changes. PMID:16464595

  19. Time Warp and the Teacher.

    ERIC Educational Resources Information Center

    Hill, John C.

    1983-01-01

    Posits the idea of effective time usage, which includes not only the efficient use of time but also the positive use of different kinds of time. Provides a table for studying effective time usage. (FL)

  20. QUADRENNIAL MCNP TIMING STUDY

    SciTech Connect

    E. C. SELCOW; B. D. LANSRUD

    2000-09-01

    The Los Alamos National Laboratory Monte Carlo N-Particle radiation transport code, MCNP, is widely used around the world for many radiation protection and shielding applications. As a well-known standard it is also an excellent vehicle for assessing the relative performance of scientific computing platforms. Every three-to-four years a new version of MCNP is released internationally by the Radiation Safety Information Computational Center (RSICC) in Oak Ridge, Tennessee. For each of the past few releases, we have also done a timing study to assess the progress of scientific computing platforms and software. These quadrennial timing studies are valuable to the radiation protection and shielding community because (a) they are performed by a recognized scientific team, not a computer vendor, (b) they use an internationally recognized code for radiation protection and shielding calculations, (c) they are eminently reproducible since the code and the test problems are internationally distributed. Further, if one has a computer platform, operating system, or compiler not presented in our results, its performance is directly comparable to the ones we report because it can use the same code, data, and test problems as we used. Our results, using a single processor per platform, indicate that hardware advances during the past three years have improved performance by less than a factor of two and software improvements have had a marginal effect on performance. The most significant impacts on performance have resulted from developments in multiprocessing and multitasking. The other most significant advance in the last three years has been the accelerated improvements in personal computers. In the last timing study, the tested personal computer was approximately a factor of four slower that the fastest machine tested, a DEC Alphastation 500. In the present study, the fastest PC tested was less than a factor of two slower than the fastest platform, which is a Compaq (previously DEC) Alpha XP1000.

  1. Space-time qubits

    SciTech Connect

    Pienaar, J. L.; Myers, C. R.; Ralph, T. C.

    2011-08-15

    We construct a qubit algebra from field creation and annihilation operators acting on a global vacuum state. Particles to be used as qubits are created from the vacuum by a near-deterministic single-particle source. Our formulation makes the space-time dependence of the qubits explicit, preparing the way for quantum computation within a field framework. The method can be generalized to deal with interacting qubits whose wave packets are not perfectly matched to each other. We give an example of how to calculate the Heisenberg evolution of a simple two-qubit circuit, taking expectation values in the field vacuum state.

  2. Real time SAR processing

    NASA Technical Reports Server (NTRS)

    Premkumar, A. B.; Purviance, J. E.

    1990-01-01

    A simplified model for the SAR imaging problem is presented. The model is based on the geometry of the SAR system. Using this model an expression for the entire phase history of the received SAR signal is formulated. From the phase history, it is shown that the range and the azimuth coordinates for a point target image can be obtained by processing the phase information during the intrapulse and interpulse periods respectively. An architecture for a VLSI implementation for the SAR signal processor is presented which generates images in real time. The architecture uses a small number of chips, a new correlation processor, and an efficient azimuth correlation process.

  3. Real time Faraday spectrometer

    DOEpatents

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  4. Ecology in deep time.

    PubMed

    Conway Morris, S

    1995-07-01

    In certain cases the extrapolation into the geological past of conditions and processes relevant to present-day ecology is not automatically valid. Do anatomical designs show improvements through time? How do we treat fossil organisms with no living parallels? What might be the influence of shifts in atmospheric composition? If the end-Cretaceous extinctions are caused by bolide impact, why does ecological trauma persist for hundreds of thousands of years? What was the ecology of the 'Cambrian explosion'? Has the role of competition been seriously underplayed? Ancient ecosystems may differ from those of today in a variety of unexpected ways. PMID:21237046

  5. THEMIS and Substorm Timing

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.

    2010-01-01

    The THEMIS mission represents the culmination of many years of planning directed towards understanding the processes that drive and trigger geomagnetic substorms. Following Akasofu's discovery of the substorm cycle, it became increasingly clear that timing questions provide the key to discriminating between proposed 'inside-out' and 'outside-in' models for substorms, triggered respectively by current disruption and magnetic reconnection. THEMIS observations provide a wealth of information that is currently being investigated to resolve this question. While observations in the magnetotail generally point towards reconnection. those on the ground point towards current disruption. This talk reviews the relevant observations and recent efforts at reconciliation.

  6. Telescope Time Allocation Tool

    NASA Astrophysics Data System (ADS)

    Alves, J.

    2005-03-01

    TaToo is ESO's new Time Allocation Tool. This software scheduler is a combination of a user-friendly graphical user interface and an intelligent constraint-programming engine fine-tuned to ESO's scheduling problem. TaToo is able to produce a high quality and reliable schedule taking into consideration all constraints of the recommended programs for all telescopes in about 15 minutes. This performance allows schedulers at ESO-VISAS to simulate and evaluate different scenarios, optimize the scheduling of engineering activities at the observatories, and in the end construct the most science efficient schedule possible.

  7. Genetic Time Travel.

    PubMed

    Krause, Johannes; Pääbo, Svante

    2016-05-01

    At its core, genetics is a historical discipline. Mutations are passed on from generation to generation and accumulate as a result of chance as well as of selection within and between populations and species. However, until recently, geneticists were confined to the study of present-day genetic variation and could only indirectly make inferences about the historical processes that resulted in the variation in present-day gene pools. This "time trap" has now been overcome thanks to the ability to analyze DNA extracted from ancient remains, and this is about to revolutionize several aspects of genetics. PMID:27183562

  8. A Matter of Time

    NASA Technical Reports Server (NTRS)

    2006-01-01

    16 February 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of the south polar residual cap where the effects of sublimation are apparent. Over extended periods of time, sublimation 'eats' away at the smoother appearing material (largely composed of frozen carbon dioxide), darkening the scarps and creating the irregularly shaped depressions that are present throughout much of the scene.

    Location near: 87.1oS, 69.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  9. Moments in Time

    PubMed Central

    Wittmann, Marc

    2011-01-01

    It has been suggested that perception and action can be understood as evolving in temporal epochs or sequential processing units. Successive events are fused into units forming a unitary experience or “psychological present.” Studies have identified several temporal integration levels on different time scales which are fundamental for our understanding of behavior and subjective experience. In recent literature concerning the philosophy and neuroscience of consciousness these separate temporal processing levels are not always precisely distinguished. Therefore, empirical evidence from psychophysics and neuropsychology on these distinct temporal processing levels is presented and discussed within philosophical conceptualizations of time experience. On an elementary level, one can identify a functional moment, a basic temporal building block of perception in the range of milliseconds that defines simultaneity and succession. Below a certain threshold temporal order is not perceived, individual events are processed as co-temporal. On a second level, an experienced moment, which is based on temporal integration of up to a few seconds, has been reported in many qualitatively different experiments in perception and action. It has been suggested that this segmental processing mechanism creates temporal windows that provide a logistical basis for conscious representation and the experience of nowness. On a third level of integration, continuity of experience is enabled by working memory in the range of multiple seconds allowing the maintenance of cognitive operations and emotional feelings, leading to mental presence, a temporal window of an individual’s experienced presence. PMID:22022310

  10. Timing of cyber conflict.

    PubMed

    Axelrod, Robert; Iliev, Rumen

    2014-01-28

    Nations are accumulating cyber resources in the form of stockpiles of zero-day exploits as well as other novel methods of engaging in future cyber conflict against selected targets. This paper analyzes the optimal timing for the use of such cyber resources. A simple mathematical model is offered to clarify how the timing of such a choice can depend on the stakes involved in the present situation, as well as the characteristics of the resource for exploitation. The model deals with the question of when the resource should be used given that its use today may well prevent it from being available for use later. The analysis provides concepts, theory, applications, and distinctions to promote the understanding strategy aspects of cyber conflict. Case studies include the Stuxnet attack on Iran's nuclear program, the Iranian cyber attack on the energy firm Saudi Aramco, the persistent cyber espionage carried out by the Chinese military, and an analogous case of economic coercion by China in a dispute with Japan. The effects of the rapidly expanding market for zero-day exploits are also analyzed. The goal of the paper is to promote the understanding of this domain of cyber conflict to mitigate the harm it can do, and harness the capabilities it can provide. PMID:24474752

  11. Time-Delay Interferometry

    NASA Astrophysics Data System (ADS)

    Tinto, Massimo; Dhurandhar, Sanjeev V.

    2014-08-01

    Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers), the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI). This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA) mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  12. Physics Back in TIME

    NASA Astrophysics Data System (ADS)

    Korsunsky, Boris

    2014-03-01

    Recently, I came into possession of an unusual item: a collection of 1928 TIME magazines. I began flipping through the pages out of sheer curiosity—and was soon astonished by the scale and the depth of their physics coverage. Back then, TIME had a special "Science" section in almost every issue and devoted quite a bit of space to the events that would hardly be mentioned in any popular magazine these days. Some of them were fleeting and merely curious, some truly timeless. Many of the articles and notes were devoted to physics: the people, the discoveries, the inventions, the conventions. I found the reading both entertaining and enlightening and would like to offer a sampler here. I hope that these little tidbits of history will lighten up the classroom discussions and help inspire your students by reminding them that physics is a dynamic, ever-changing field to which they may well contribute one day. I have found that my own students love it when a little bit of history is brought up; it always generates interesting questions and seems to spark the students' interest in the topic.

  13. Multiple sclerosis: changing times.

    PubMed

    Kurtzke, J F

    1991-01-01

    Multiple sclerosis (MS) is distributed about the world in three zones of high, medium, and low frequency. All high- and medium-risk areas are among predominantly white populations. Migration studies indicate MS is already acquired by age 15 in high-risk endemic areas and that low-to-high migrants increase their risk from age 11 years. Therefore MS is an environmental disease ordinarily acquired in adolescence with a long incubation before symptom onset. Susceptibility is limited to the period from about age 11 to 47. In general, MS death rates have been declining over time while prevalence rates have increased. Incidence rates have also increased, however, in: northeastern Scotland; Turku, Finland; Hordaland, Norway; Rochester, Minn.; Lower Saxony; several areas of Italy. Incidence was unchanged in northernmost Norway. Conversely, incidence and prevalence rates have decreased in the Shetland-Orkneys; there was a cyclical pattern in incidence in Rostock, GDR; and there was a transient doubling of incidence in Iceland in the post-World War II decade. In the Faroe Islands, MS was absent before 1943 when a major point-source epidemic began, reaching an incidence rate of 10 per 100,000 population in 1945. This was followed by two consecutively smaller epidemics with respective peaks each about 12 years later, and there is now a new epidemic IV on these islands. Explanations for changing incidence of MS over time should bring us closer to solving the etiology of this disease. PMID:2062411

  14. Prime time sexual harrassment.

    PubMed

    Grauerholz, E; King, A

    1997-04-01

    This study explores the explicit and implicit messages of sexual harassment that viewers receive when viewing prime-time television in the US. A content analysis of 48 hours of prime-time television reveals that sexual harassment on television is both highly visible and invisible. Sexual harassment is rendered visible simply by its prominence in these programs. Incidents involving quid-pro-quo harassment and environmental harassment occur with regularity on television. Furthermore, about 84% of the shows studied contained at least one incident of sexual harassment; yet these acts of sexual harassment remained largely invisible because none of the behaviors were labeled as sexual harassment. These incidents are presented in humorous ways, and victims are generally unharmed and very effective at ending the harassment. Although such programs may actually reflect the reality of many women's lives in terms of prevalence of sexual harassment, they perpetuate several myths about sexual harassment, such as that sexual harassment is not serious and that victims should be able to handle the situations themselves. PMID:12294811

  15. The Sun in Time

    NASA Technical Reports Server (NTRS)

    Adams, Mitzi L.; Bero, Elizabeth; Sever, Thomas L.

    1999-01-01

    Leveraging funds from NASA's Initiative to Develop Education through Astronomy and Space Science (IDEAS) program, we combined the expertise of an archaeoastronomer, a solar scientist, and a teacher to trace humankind's view of the Sun and how that has changed, from the time of Stonehenge in about 1800 B.C.E., to the time of the Maya in 700 C.E., up to the modem era. Our program was aimed at middle-school students in an attempt to explain not only how science is done today, but how science has evolved from the observations of ancient societies. From these varied cultures, we touched on methods of observing the Sun, ideas of the composition of the Sun, and the relationship of the Sun to everyday life. Further, using the von Braun Astronomical Society's Planetarium in Huntsville, Alabama as a test-bed for the program, we illustrated concepts such as solstices, equinoxes, and local noon with approximately 800 eighth grade students from the local area. Our presentation to SEPA will include a description of NASA's IDEAS program and how to go about partnering with a NASA astronomer, some slides from our planetarium program and web-site, and some hands-on activities.

  16. DNA Replication Timing

    PubMed Central

    Rhind, Nicholas; Gilbert, David M.

    2013-01-01

    Patterns of replication within eukaryotic genomes correlate with gene expression, chromatin structure, and genome evolution. Recent advances in genome-scale mapping of replication kinetics have allowed these correlations to be explored in many species, cell types, and growth conditions, and these large data sets have allowed quantitative and computational analyses. One striking new correlation to emerge from these analyses is between replication timing and the three-dimensional structure of chromosomes. This correlation, which is significantly stronger than with any single histone modification or chromosome-binding protein, suggests that replication timing is controlled at the level of chromosomal domains. This conclusion dovetails with parallel work on the heterogeneity of origin firing and the competition between origins for limiting activators to suggest a model in which the stochastic probability of individual origin firing is modulated by chromosomal domain structure to produce patterns of replication. Whether these patterns have inherent biological functions or simply reflect higher-order genome structure is an open question. PMID:23838440

  17. Timing of cyber conflict

    PubMed Central

    Axelrod, Robert; Iliev, Rumen

    2014-01-01

    Nations are accumulating cyber resources in the form of stockpiles of zero-day exploits as well as other novel methods of engaging in future cyber conflict against selected targets. This paper analyzes the optimal timing for the use of such cyber resources. A simple mathematical model is offered to clarify how the timing of such a choice can depend on the stakes involved in the present situation, as well as the characteristics of the resource for exploitation. The model deals with the question of when the resource should be used given that its use today may well prevent it from being available for use later. The analysis provides concepts, theory, applications, and distinctions to promote the understanding strategy aspects of cyber conflict. Case studies include the Stuxnet attack on Iran’s nuclear program, the Iranian cyber attack on the energy firm Saudi Aramco, the persistent cyber espionage carried out by the Chinese military, and an analogous case of economic coercion by China in a dispute with Japan. The effects of the rapidly expanding market for zero-day exploits are also analyzed. The goal of the paper is to promote the understanding of this domain of cyber conflict to mitigate the harm it can do, and harness the capabilities it can provide. PMID:24474752

  18. Time to talk.

    PubMed

    Trubo, R

    1993-01-01

    In the US, a workshop has been developed to provide parents with accurate information about sexuality and contraception that they can convey to their children, to help parents bridge the communication gap, to deliver guidelines for fostering their children's self-esteem, and to provide a framework that parents can use to explain their own values about sexuality to their children. "Time to Talk" was launched in Houston, Texas, in 1992. The initial workshops were conducted at local hospitals and consisted of 150-minute sessions attended by parents and their children. Most of the parents had children between the ages of 11 and 14 and found the workshops to be valuable. The workshop was developed because, although teenagers consider their parents their most valuable source of sex information, only one-third of US children surveyed had discussed birth control with their parents. Without parental guidance, young teens become pregnant or acquire sexually transmitted diseases (STDs). Workshop parents are advised to begin their discussions before they are perfectly comfortable with their topic, that discomfort is perfectly acceptable. The interactive nature of the workshop is fostered by giving parents exercises designed to help them become better sex educators at home. Small group discussions followed by written assessments allow parents to share their anxieties as well as to articulate their need for information and their desire to learn techniques for conversations about sexuality. Parents are urged to give their children permission to talk and learn about sexuality at any time and any age; parents are also encouraged to take advantage of opportunities to initiate discussions. Workshop participants are told that talking about sex does not encourage early experimentation, in fact, it helps youngsters to postpone the initiation of intercourse and to show more responsibility in using contraceptives. A typical workshop includes the presentation of medical and biological information and role-playing. The parents take home comprehensive booklets and fact sheets with information on sexuality, contraception, and sexually transmitted diseases and answers to many of the questions adolescents ask. Workshop facilitators consider "Time to Talk" only the first step in a lifelong process of sex education. There is no doubt that teens will get information about sex, the only question is how and where they will get it. PMID:12318475

  19. Funding Full-Time Study through Part-Time Work

    ERIC Educational Resources Information Center

    Richardson, Mark; Evans, Carl; Gbadamosi, Gbolahan

    2009-01-01

    Full-time students engaged in part-time studies have been a subject of increasing academic attention. This study extends work in this area by examining: the extent to which full-time undergraduate students undertake part-time employment, the reasons for working whilst studying full-time and the extent to which students relate their part-time…

  20. Real time automated inspection

    DOEpatents

    Fant, K.M.; Fundakowski, R.A.; Levitt, T.S.; Overland, J.E.; Suresh, B.R.; Ulrich, F.W.

    1985-05-21

    A method and apparatus are described relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections. 43 figs.

  1. Time encoded radiation imaging

    DOEpatents

    Marleau, Peter; Brubaker, Erik; Kiff, Scott

    2014-10-21

    The various technologies presented herein relate to detecting nuclear material at a large stand-off distance. An imaging system is presented which can detect nuclear material by utilizing time encoded imaging relating to maximum and minimum radiation particle counts rates. The imaging system is integrated with a data acquisition system that can utilize variations in photon pulse shape to discriminate between neutron and gamma-ray interactions. Modulation in the detected neutron count rates as a function of the angular orientation of the detector due to attenuation of neighboring detectors is utilized to reconstruct the neutron source distribution over 360 degrees around the imaging system. Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon scintillation material in the imager, the photons generated by the scintillation material are converted to electrical energy from which the respective neutrons/gamma rays can be determined and, accordingly, a direction to, and the location of, a radiation source identified.

  2. Real time automated inspection

    DOEpatents

    Fant, Karl M.; Fundakowski, Richard A.; Levitt, Tod S.; Overland, John E.; Suresh, Bindinganavle R.; Ulrich, Franz W.

    1985-01-01

    A method and apparatus relating to the real time automatic detection and classification of characteristic type surface imperfections occurring on the surfaces of material of interest such as moving hot metal slabs produced by a continuous steel caster. A data camera transversely scans continuous lines of such a surface to sense light intensities of scanned pixels and generates corresponding voltage values. The voltage values are converted to corresponding digital values to form a digital image of the surface which is subsequently processed to form an edge-enhanced image having scan lines characterized by intervals corresponding to the edges of the image. The edge-enhanced image is thresholded to segment out the edges and objects formed by the edges are segmented out by interval matching and bin tracking. Features of the objects are derived and such features are utilized to classify the objects into characteristic type surface imperfections.

  3. Solar wind travel time

    NASA Astrophysics Data System (ADS)

    Russell, C. T.

    A useful rule of thumb in solar terrestrial studies is that the solar wind travels 4 Earth radii (RE) per minute. Long-term studies of solar wind velocity [e.g., Luhmann et al., 1993; 1994] show that the median velocity is about 420 km/s, corresponding to 3.96 RE min-1. The quartiles are about 370 km/s and 495 km/s, corresponding to 3.48 Re min-1 and 4.66 Re min-1 respectively. This number helps estimate the delays expected when observing a discontinuity at a solar wind monitor; one example is ISEE-3 when it was at the forward libration point (about 60 min). It is also helpful for estimating how much time passes before the dayside magnetosphere is compressed as denser solar wind flows by (about 2.5 min).

  4. Timing in the Testis.

    PubMed

    Bittman, Eric L

    2016-02-01

    The testis provides not just one but several models of temporal organization. The complexity of its rhythmic function arises in part from its compartmentalization and diversity of cell types: not only does the testis produce gametes, but it also serves as the major source of circulating androgens. Within the seminiferous tubules, the germ cells divide and differentiate while in intimate contact with Sertoli cells. The tubule is highly periodic: a spermatogenic wave travels along its length to determine the timing of the commitment of spermatogonia to differentiate, the phases of meiotic division, and the rate of differentiation of the postmeiotic germ cells. Recent evidence indicates that oscillations of retinoic acid play a major role in determining periodicity of the seminiferous epithelium. In the interstitial space, Leydig cells produce the steroid hormones required both for the completion of spermatogenesis and the development and maintenance of male sexual characteristics throughout the body. This endocrine output also oscillates; although the pulse generator lies outside the gonad, the steroidogenic function of Leydig cells is tuned to a regular episodic input. While the oscillations of the intratubular and interstitial cells have multihour (ultradian) and multiday (infradian) periodicities, respectively, the functions of both compartments also display dramatic seasonal rhythms. Furthermore, circadian rhythms are evident in some of the cell types, although their amplitude and pervasiveness are not as great as in many other tissues of the same organism, and their detection may require methods that recognize the heterogeneity of the testis. This review examines the periodicity of testicular function along multiple time scales. PMID:26656623

  5. Cell complexes through time

    NASA Astrophysics Data System (ADS)

    Klette, Reinhard

    2000-10-01

    The history of cell complexes is closely related to the birth and development of topology in general. Johann Benedict Listing (1802 - 1882) introduced the term 'topology' into mathematics in a paper published in 1847, and he also defined cell complexes for the first time in a paper published in 1862. Carl Friedrich Gauss (1777 - 1855) is often cited as the one who initiated these ideas, but he did not publish either on topology or on cell complexes. The pioneering work of Leonhard Euler (1707 - 1783) on graphs is also often cited as the birth of topology, and Euler's work was cited by Listing in 1862 as a stimulus for his research on cell complexes. There are different branches in topology which have little in common: point set topology, algebraic topology, differential topology etc. Confusion may arise if just 'topology' is specified, without clarifying the used concept. Topological subjects in mathematics are often related to continuous models, and therefore quite irrelevant to computer based solutions in image analysis. Compared to this, only a minority of topology publications in mathematics addresses discrete spaces which are appropriate for computer-based image analysis. In these cases, often the notion of a cell complex plays a crucial role. This paper briefly reports on a few of these publications. This paper is not intended to cover the very lively progress in cell complex studies within the context of image analysis during the last two decades. Basically it stops its historic review at the time when this subject in image analysis research gained speed in 1980 - 1990. As a general point of view, the paper indicates that image analysis contributes to a fusion of topological concepts, the geometric and the abstract cell structure approach and point set topology, which may lead towards new problems for the study of topologies defined on geometric or abstract cell complexes.

  6. Why do flamingos stand on one leg?

    PubMed

    Anderson, Matthew J; Williams, Sarah A

    2010-01-01

    A series of observational studies of captive Caribbean flamingos Phoenicopterus ruber were conducted to determine why flamingos rest on one leg. While frequently asked by the general public, this basic question has remained unanswered by the scientific community. Here we suggest that the latency of flamingos to initiate forward locomotion following resting on one leg is significantly longer than following resting on two, discounting the possibility that unipedal resting reduces muscle fatigue or enhances predatory escape. Additionally, we demonstrate that flamingos do not display lateral preferences at the individual or group levels when resting on one leg, with each bird dividing its resting time across both legs. We show that while flamingos prefer resting on one leg to two regardless of location, the percentage of birds resting on one leg is significantly higher among birds standing in the water than among those on land. Finally, we demonstrate a negative relationship between temperature and the percentage of observed birds resting on one leg, such that resting on one leg decreases as temperature rises. Results strongly suggest that unipedal resting aids flamingos in thermoregulation. PMID:19637281

  7. Engaged Time in the Classroom

    ERIC Educational Resources Information Center

    Johns E., Beverly H.; Crowley, Paula; Guetzloe, Eleanor

    2008-01-01

    Foremost in an effective curriculum for students with emotional and behavioral disorder (E/BD) is a high level of engaged time--time spent doing meaningful learning activities. Engaged time (time-on-task) is the portion of instructional time that students spend directly involved in learning activities. Walker and Severson (1992) defined the…

  8. Galaxies Across Cosmic Time

    NASA Astrophysics Data System (ADS)

    Urry, C. Megan

    2011-05-01

    The Astro2010 Science Frontier Panel Galaxies Across Cosmic Time (GCT) study encompassed the main constituents of the universe across 90 percent of its history, from the formation and evolution of structures such as galaxies, clusters of galaxies, and the "cosmic web” of intergalactic matter, to the stars, gas, dust, supermassive black holes, and dark matter of which they are composed. These elements are coupled in a complicated evolutionary progression as matter accretes into galaxies, stars form and evolve, black holes grow, supernovae and active galactic nuclei expel matter and energy into the intergalactic medium (IGM), and galaxies collide and merge. The GCT panel was charged with formulating 4 questions and identifying one area with unusual discovery potential that it believes will form the focus for research in the coming decade. The questions are: (1) How do cosmic structures form and evolve? (2) How do baryons cycle in and out of galaxies, and what do they do while they are there? (3) How do black holes grow, radiate, and influence their surroundings? (4) What were the first objects to light up the universe and when did they do it? We identified the epoch of reionization as the Discovery Area. This presentation reviews highlights from the GCT report, some of which imply a need for new observational facilities, whereas others could be done with existing facilities, possibly with a reprogramming of resources.

  9. Happiness in texting times

    PubMed Central

    Hevey, David; Hand, Karen; MacLachlan, Malcolm

    2015-01-01

    Assessing national levels of happiness has become an important research and policy issue in recent years. We examined happiness and satisfaction in Ireland using phone text messaging to collect large-scale longitudinal data from 3,093 members of the general Irish population. For six consecutive weeks, participants’ happiness and satisfaction levels were assessed. For four consecutive weeks (weeks 2–5) a different random third of the sample got feedback on the previous week’s mean happiness and satisfaction ratings. Text messaging proved a feasible means of assessing happiness and satisfaction, with almost three quarters (73%) of participants completing all assessments. Those who received feedback on the previous week’s mean ratings were eight times more likely to complete the subsequent assessments than those not receiving feedback. Providing such feedback data on mean levels of happiness and satisfaction did not systematically bias subsequent ratings either toward or away from these normative anchors. Texting is a simple and effective means to collect population level happiness and satisfaction data. PMID:26441804

  10. Real time polarimetric dehazing.

    PubMed

    Mudge, Jason; Virgen, Miguel

    2013-03-20

    Remote sensing is a rich topic due to its utility in gathering detailed accurate information from locations that are not economically feasible traveling destinations or are physically inaccessible. However, poor visibility over long path lengths is problematic for a variety of reasons. Haze induced by light scatter is one cause for poor visibility and is the focus of this article. Image haze comes about as a result of light scattering off particles and into the imaging path causing a haziness to appear on the image. Image processing using polarimetric information of light scatter can be used to mitigate image haze. An imaging polarimeter which provides the Stokes values in real time combined with a "dehazing" algorithm can automate image haze removal for instant applications. Example uses are to improve visual display providing on-the-spot detection or imbedding in an active control loop to improve viewing and tracking while on a moving platform. In addition, removing haze in this manner allows the trade space for a system operational waveband to be opened up to bands which are object matched and not necessarily restricted by scatter effects. PMID:23518739

  11. Time-Reversal Violation

    NASA Astrophysics Data System (ADS)

    Bernabéu, José; Martínez-Vidal, Fernando

    2015-10-01

    The violation of CP symmetry between matter and antimatter in the neutral K and B meson systems is well established, with a high degree of consistency between all available experimental measurements and with the Standard Model of particle physics. On the basis of the up-to-now-unbroken CPT symmetry, the violation of CP symmetry strongly suggests that the behavior of these particles under weak interactions must also be asymmetric under time reversal T. Many searches for T violation have been performed and proposed using different observables and experimental approaches. These include T-odd observables, such as triple products in weak decays, and genuine observables, such as permanent electric dipole moments of nondegenerate stationary states and the breaking of the reciprocity relation. We discuss the conceptual basis of the required exchange of initial and final states with unstable particles, using quantum entanglement and the decay as a filtering measurement, for the case of neutral B and K mesons. Using this method, the BaBar experiment at SLAC has clearly observed T violation in B mesons.

  12. [Time to be young].

    PubMed

    1997-01-01

    The project entitled "Tempo de ser jovem" (time to be young) is implemented in Campanha, in the city of Porto, Portugal, to prevent dropping out from schools, drug abuse, and adolescent pregnancy in the Elementary School of Cerco, Porto, where many pupils have problems with fitting in owing to socioeconomic disadvantages and underprivileged status. The project was developed by the professionals of the local health center and by some teachers. Youth groups were formed to perform activities in health, the environment, social communication, and sports. The prevention of rising adolescent pregnancy was a goal because 25% of all births occur to girls aged 19 and under. Family planning is also vital because of the frequency of repeated pregnancies. Psychologists render counseling assistance to young people and local employment centers also offer social and vocational assistance in gardening, cleaning and domestic work in residential quarters. In the family planning courses groups of 15-20 persons are included and practical training is carried out dealing with nutrition during pregnancy as well as for adolescents and nursing mothers. Visits to homes of parents are also made and individual consultation is also offered. Motivation is the mainstay of all activities dealing with psychosocial aspects of adolescent pregnancy and motherhood, health and disease, and social marketing. PMID:12179269

  13. Time to redefine Myeloma.

    PubMed

    Pratt, Guy; Bowcock, Stella; Chantry, Andrew; Cook, Gordon; Jackson, Graham; Lai, Maggie; Low, Eric; Mulholland, Nicola; Owen, Roger; Rabin, Neil; Ramasamy, Karthik; Snowden, John A; Streetly, Matthew; Wechalekar, Ashutosh; Yong, Kwee; Bird, Jenny

    2015-10-01

    In November 2014 the International Myeloma Working Group (IMWG) revised the definition of multiple myeloma, such that asymptomatic patients with newly diagnosed multiple myeloma without any of the traditional 'CRAB' (hypercalcaemia, renal impairment, anaemia, bone disease) end organ damage criteria but with one of three new criteria would be recommended to start treatment. Previously, the standard of care for such patients was expectant management. These three new criteria are: greater than 60% clonal plasma cells on bone marrow biopsy, a serum free light chain (sFLC) ratio of >100 (the involved sFLC must be >100 mg/l) and greater than one unequivocal focal lesion on advanced imaging (low dose whole body computerized tomography, magnetic resonance imaging, (18) F fluorodeoxyglucose positron emission tomography). Although this would appear to affect a small number of patients, the impact of these changes are broad, leading to an increased use of advanced imaging, a debate around the management of patients previously diagnosed with smouldering myeloma, changed terminology and clinical trial design and an extension of the use of biomarkers. For the first time the philosophy of treatment in myeloma will change from treatment initiation only being triggered by overt end organ damage to an era where sub clinical risk factors will also be taken into account. PMID:26221971

  14. Management Styles and Techniques: Time.

    ERIC Educational Resources Information Center

    Matthews, Priscilla J.

    1987-01-01

    Discusses strategies to improve individuals' use of time and personal satisfaction through time management. The 126-item bibliography includes citations for time management in general and special sections for career development, family and parenting, women, and home management. (CLB)

  15. Conformal gravity and time

    NASA Astrophysics Data System (ADS)

    Hazboun, Jeffrey Shafiq

    2014-10-01

    Cartan geometry provides a rich formalism from which to look at various geometrically motivated extensions to general relativity. In this manuscript, we start by motivating reasons to extend the theory of general relativity. We then introduce the reader to our technique, called the quotient manifold method, for extending the geometry of spacetime. We will specifically look at the class of theories formed from the various quotients of the conformal group. Starting with the conformal symmetries of Euclidean space, we construct a manifold where time manifests as a part of the geometry. Though there is no matter present in the geome- try studied here, geometric terms analogous to dark energy and dark matter appear when we write down the Einstein tensor. Specifically, the quotient of the conformal group of Euclidean four-space by its Weyl subgroup results in a geometry possessing many of the properties of relativistic phase space, including both a natural symplectic form and nondegenerate Killing metric. We show the general solution possesses orthogonal Lagrangian submanifolds, with the induced metric and the spin connection on the submanifolds necessarily Lorentzian, despite the Euclidean starting point. By examining the structure equations of the biconformal space in an orthonormal frame adapted to its phase space properties, we also find two new tensor fields exist in this geometry, not present in Riemannian geometry. The first is a combination of the Weyl vector with the scale factor on the metric, and determines the time-like directions on the submanifolds. The second comes from the components of the spin connection, symmetric with respect to the new metric. Though this field comes from the spin connection, it transforms ho- mogeneously. Finally, we show in the absence of Cartan curvature or sources, the configuration space has geometric terms equivalent to a perfect fluid and a cosmological constant. We complete the analysis of this homogeneous space by transforming the known, general solution of the Maurer-Cartan equations into the orthogonal, Lagrangian basis. This results in a signature-changing metric, just as in the work of Spencer and Wheeler, however without any conditions on the curvature of the momentum sector. The Riemannian curvatures of the two submanifolds are directly related. We investigate the case where the curvature on the momentum submanifold vanishes, while the curvature of the configuration submanifold gives an effective energy-momentum tensor corresponding to a perfect fluid. In the second part of this manuscript, we look at the most general curved biconformal geometry dictated by the Wehner-Wheeler action. We use the assemblage of structure equations, Bianchi identities, and field equations to show how the geometry of the manifolds self-organizes into trivial Weyl geometries, which can then be gauged to Riemannian geometries. The Bianchi identities reveal the strong relationships between the various curvatures, torsions, and cotorsions. The discussion of the curved case culminates in a number of simplifying restrictions that show general relativity as the base of the more general theory.

  16. SLH Timing Belt Powertrain

    SciTech Connect

    Schneider, Abe

    2014-04-09

    The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine—, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon-#12;fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning a timing-belt based hydroEngine —powertrain: 1. Can a belt handle the high torques and power loads demanded by the SLH? (Yes.) 2. Can the SLH blades be mounted to belt with a connection that can withstand the loads encountered in operation? (Yes.) 3. Can the belt, with blade attachments, live through the required cyclic loading? (Yes.) The research adds to the general understanding of sustainable small hydropower systems by using innovative system testing to develop and demonstrate performance of a novel powertrain solution, enabling a new type of hydroelectric turbine to be commercially developed. The technical effectiveness of the methods investigated has been shown to be positive through an extensive design and testing process accommodating many constraints and goals, with a major emphasis on high cycle fatigue life. Economic feasibility of the innovations has been demonstrated through many iterations of design for manufacturability and cost reduction. The project is of benefit to the public because it has helped to develop a solution to a major problem -- despite the large available potential for new low-head hydropower, high capital costs and high levelized cost of electricity (LCOE) continue to be major barriers to project development. The hydroEngine— represents a significant innovation, leveraging novel fluid mechanics and mechanical configuration to allow lower-cost turbine manufacture and development of low head hydropower resources.

  17. Fourteen Times the Earth

    NASA Astrophysics Data System (ADS)

    2004-08-01

    ESO HARPS Instrument Discovers Smallest Ever Extra-Solar Planet Summary A European team of astronomers [1] has discovered the lightest known planet orbiting a star other than the sun (an "exoplanet"). The new exoplanet orbits the bright star mu Arae located in the southern constellation of the Altar. It is the second planet discovered around this star and completes a full revolution in 9.5 days. With a mass of only 14 times the mass of the Earth, the new planet lies at the threshold of the largest possible rocky planets, making it a possible super Earth-like object. Uranus, the smallest of the giant planets of the Solar System has a similar mass. However Uranus and the new exoplanet differ so much by their distance from the host star that their formation and structure are likely to be very different. This discovery was made possible by the unprecedented accuracy of the HARPS spectrograph on ESO's 3.6-m telescope at La Silla, which allows radial velocities to be measured with a precision better than 1 m/s. It is another clear demonstration of the European leadership in the field of exoplanet research. PR Photo 25a/04: The HARPS Spectrograph and the 3.6m Telescope PR Photo 25b/04: Observed Velocity Variation of mu Arae (3.6m/HARPS, 1.2m Swiss/CORALIE, AAT/UCLES) PR Photo 25c/04: Velocity Variation of mu Arae Observed by HARPS (3.6m/HARPS) PR Photo 25d/04: "Velocity Curve" of mu Arae A unique planet hunting machine ESO PR Photo 25a/04 ESO PR Photo 25a/04 The HARPS Spectrograph and the 3.6m Telescope [Preview - JPEG: 602 x 400 pix - 211k] [Normal - JPEG: 1202 x 800 pix - 645k] Caption: ESO PR Photo 25a/04 represents a montage of the HARPS spectrograph and the 3.6m telescope at La Silla. The upper left shows the dome of the telescope, while the upper right illustrates the telescope itself. The HARPS spectrograph is shown in the lower image during laboratory tests. The vacuum tank is open so that some of the high-precision components inside can be seen. Since the first detection in 1995 of a planet around the star 51 Peg by Michel Mayor and Didier Queloz from the Geneva Observatory (Switzerland), astronomers have learned that our Solar System is not unique, as more than 120 giant planets orbiting other stars were discovered mostly by radial-velocity surveys (cf. ESO PR 13/00, ESO PR 07/01, and ESO PR 03/03). This fundamental observational method is based on the detection of variations in the velocity of the central star, due to the changing direction of the gravitational pull from an (unseen) exoplanet as it orbits the star. The evaluation of the measured velocity variations allows to deduce the planet's orbit, in particular the period and the distance from the star, as well as a minimum mass [2]. The continued quest for exoplanets requires better and better instrumentation. In this context, ESO undoubtedly took the leadership with the new HARPS spectrograph (High Accuracy Radial Velocity Planet Searcher) of the 3.6-m telescope at the ESO La Silla Observatory (see ESO PR 06/03). Offered in October 2003 to the research community in the ESO member countries, this unique instrument is optimized to detect planets in orbit around other stars ("exoplanets") by means of accurate (radial) velocity measurements with an unequalled precision of 1 metre per second. HARPS was built by a European Consortium [3] in collaboration with ESO. Already from the beginning of its operation, it has demonstrated its very high efficiency. By comparison with CORALIE, another well known planet-hunting optimized spectrograph installed on the Swiss-Euler 1.2-m telescope at La Silla (cf ESO PR 18/98, 12/99, 13/00), the typical observation times have been reduced by a factor one hundred and the accuracy of the measurements has been increased by a factor ten. These improvements have opened new perspectives in the search for extra-solar planets and have set new standards in terms of instrumental precision. The planetary system around mu Arae The star mu Arae is about 50 light years away. This solar-like star is located in the southern constellation Ara (the Altar) and is bright enough (5th magnitude) to be observed with the unaided eye. Mu Arae was already known to harbour a Jupiter-sized planet with a 650 days orbital period. Previous observations also hinted at the presence of another companion (a planet or a star) much further away. The new measurements obtained by the astronomers on this object, combined with data from other teams confirm this picture. But as François Bouchy, member of the team, states: "Not only did the new HARPS measurements confirm what we previously believed to know about this star but they also showed that an additional planet on short orbit was present. And this new planet appears to be the smallest yet discovered around a star other than the sun. This makes mu Arae a very exciting planetary system." "Listening" to the star ESO PR Photo 25b/04 ESO PR Photo 25b/04 Observed Velocity Variation of mu Arae [Preview - JPEG: 440 x 400 pix - 98k] [Normal - JPEG: 879 x 800 pix - 230k] ESO PR Photo 25c/04 ESO PR Photo 25c/04 Velocity Variation of mu Arae Observed by HARPS [Preview - JPEG: 460 x 400 pix - 90k] [Normal - JPEG: 919 x 800 pix - 215k] Captions: ESO PR Photo 25b/04 shows the measurements of the radial velocity of the star mu Arae obtained by HARPS on the ESO 3.6m telescope at La Silla (green triangles), CORALIE on the Swiss Leonhard Euler 1.2m telescope also on La Silla (red dots) and UCLES on the Anglo-Australian Telescope (blue circles). The solid line shows the best fit to the measurements, assuming the existence of two planets and an additional long-period companion. The fact that the line happens to have a given width is related to the existence of the newly found short period planet. The data shown span the interval from July 1998 to August 2004. ESO PR Photo 25c/04 illustrates the high-quality radial velocity measurements obtained with HARPS. Here also, the solid line shows the best fit to the measurements, assuming the existence of two planets. The data were obtained over a time span of 80 days and the first points shown are the data from the 8 nights in June. Note that the full span of the vertical axis is only 40 m/s! Error bars indicate the accuracy of the measurements. The lower part of the diagram displays the deviation of the measurements from the best fit. ESO PR Photo 25d/04 ESO PR Photo 25d/04 Observed Velocity Variation of mu Arae [Preview - JPEG: 440 x 400 pix - 78k] [Normal - JPEG: 879 x 800 pix - 171k] Caption: ESO PR Photo 25d/04 displays the HARPS radial velocity measurements phase-folded with the orbital period of the newly found exoplanet (9.5 days). The measurements have been corrected from the effect of the two longer period companions. The semi-amplitude of the curve is less than 5 m/s! Coupled with the 9.5 days orbital period, this implies a minimum mass for the newly discovered planet of 14 times the mass of the Earth. During 8 nights in June 2004, mu Arae was repeatedly observed and its radial velocity measured by HARPS to obtain information on the interior of the star. This so-called astero-seismology technique (see ESO PR 15/01) studies the small acoustic waves which make the surface of the star periodically pulsate in and out. By knowing the internal structure of the star, the astronomers aimed at understanding the origin of the unusual amount of heavy elements observed in its stellar atmosphere. This unusual chemical composition could provide unique information to the planet formation history. Says Nuno Santos, another member of the team: "To our surprise, the analysis of the new measurements revealed a radial velocity variation with a period of 9.5 days on top of the acoustic oscillation signal!" This discovery has been made possible thanks to the large number of measurements obtained during the astero-seimology campaign. From this date, the star, that was also part of the HARPS consortium survey programme, was regularly monitored with a careful observation strategy to reduce the "seismic noise" of the star. These new data confirmed both the amplitude and the periodicity of the radial velocity variations found during the 8 nights in June. The astronomers were left with only one convincing explanation to this periodic signal: a second planet orbits mu Arae and accomplishes a full revolution in 9.5 days. But this was not the only surprise: from the radial velocity amplitude, that is the size of the wobble induced by the gravitational pull of the planet on the star, the astronomers derived a mass for the planet of only 14 times the mass of the Earth! This is about the mass of Uranus, the smallest of the giant planets in the solar system. The newly found exoplanet therefore sets a new record in the smallest planet discovered around a solar type star. At the boundary The mass of this planet places it at the boundary between the very large earth-like (rocky) planets and giant planets. As current planetary formation models are still far from being able to account for all the amazing diversity observed amongst the extrasolar planets discovered, astronomers can only speculate on the true nature of the present object. In the current paradigm of giant planet formation, a core is formed first through the accretion of solid "planetesimals". Once this core reaches a critical mass, gas accumulates in a "runaway" fashion and the mass of the planet increases rapidly. In the present case, this later phase is unlikely to have happened for otherwise the planet would have become much more massive. Furthermore, recent models having shown that migration shortens the formation time, it is unlikely that the present object has migrated over large distances and remained of such small mass. This object is therefore likely to be a planet with a rocky (not an icy) core surrounded by a small (of the order of a tenth of the total mass) gaseous envelope and would therefore qualify as a "super-Earth". Further Prospects The HARPS consortium, led by Michel Mayor (Geneva Observatory, Switzerland), has been granted 100 observing nights per year during a 5-year period at the ESO 3.6-m telescope to perform one of the most ambitious systematic searches for exoplanets so far implemented worldwide. To this aim, the consortium repeatedly measures velocities of hundreds of stars that may harbour planetary systems. The detection of this new light planet after less than 1 year of operation demonstrates the outstanding potential of HARPS for detecting rocky planets on short orbits. Further analysis shows that performances achieved with HARPS make possible the detection of big "telluric" planets with only a few times the mass of the Earth. Such a capability is a major improvement compared to past planet surveys. Detection of such rocky objects strengthens the interest of future transit detections from space with missions like COROT, Eddington and KEPLER that shall be able to measure their radius. More information The research described in this Press release has been submitted for publication to the leading astrophysical journal "Astronomy and Astrophysics". A preprint is available as a postscript file at http://www.oal.ul.pt/~nuno/. Notes [1]: The team is composed of Nuno Santos (Centro de Astronomia e Astrofisica da Universidade de Lisboa, Portugal), François Bouchy and Jean-Pierre Sivan (Laboratoire d'astrophysique de Marseille, France), Michel Mayor, Francesco Pepe, Didier Queloz, Stéphane Udry, and Christophe Lovis (Observatoire de l'Université de Genève, Switzerland), Sylvie Vauclair, Michael Bazot (Toulouse, France), Gaspare Lo Curto and Dominique Naef (ESO), Xavier Delfosse (LAOG, Grenoble, France), Willy Benz and Christoph Mordasini (Physikalisches Institut der Universität Bern, Switzerland), and Jean-Louis Bertaux (Service d'Aéronomie de Verrière-le-Buisson, Paris, France). [2] A fundamental limitation of the radial-velocity method is the unknown of the inclination of the planetary orbit that only allows the determination of a lower mass limit for the planet. However, statistical considerations indicate that in most cases, the true mass will not be much higher than this value. The mass units for the exoplanets used in this text are 1 Jupiter mass = 22 Uranus masses = 318 Earth masses; 1 Uranus mass = 14.5 Earth masses. [3] HARPS has been designed and built by an international consortium of research institutes, led by the Observatoire de Genève (Switzerland) and including Observatoire de Haute-Provence (France), Physikalisches Institut der Universität Bern (Switzerland), the Service d'Aeronomie (CNRS, France), as well as ESO La Silla and ESO Garching.

  18. Group Time: Taking a "Humor Break" at Group Time

    ERIC Educational Resources Information Center

    Church, Ellen Booth

    2005-01-01

    January is a perfect time to insert a strong dose of humor into group time gatherings. Oftentimes, children have tired of the predictable pattern of group meetings and need some change. Humor-filled group time activities can be the best secret remedy. Not only will children become more interested in the group time meetings (and therefore listen…

  19. Reaction Time and Anticipation Time: Effects of Development.

    ERIC Educational Resources Information Center

    Thomas, Jerry R.; And Others

    1981-01-01

    Results of a study indicated that, as age increased from seven to 20 years, reaction time decreased, with males having a more rapid reaction time than females. Beginning at age 10 or 11, subjects developed better motor plans and relied less on rapid reaction time to achieve good anticipation time. (FG)

  20. Group Time: Taking a "Humor Break" at Group Time

    ERIC Educational Resources Information Center

    Church, Ellen Booth

    2005-01-01

    January is a perfect time to insert a strong dose of humor into group time gatherings. Oftentimes, children have tired of the predictable pattern of group meetings and need some change. Humor-filled group time activities can be the best secret remedy. Not only will children become more interested in the group time meetings (and therefore listen

  1. Improvement in the physiological function and standing stability based on kinect multimedia for older people

    PubMed Central

    Chen, Chih-Chen

    2016-01-01

    [Purpose] The increase in the Taiwanese older population is associated with age-related inconveniences. Finding adequate and simple physical activities to help the older people maintaining their physiological function and preventing them from falls has become an urgent social issue. [Subjects and Methods] This study aimed to design a virtual exercise training game suitable for Taiwanese older people. This system will allow for the maintenance of the physiological function and standing stability through physical exercise, while using a virtual reality game. The participants can easily exercise in a carefree, interactive environment. This study will use Kinect for Windows for physical movement detection and Unity software for virtual world development. [Results] Group A and B subjects were involved in the exercise training method of Kinect interactive multimedia for 12 weeks. The results showed that the functional reach test and the unipedal stance test improved significantly. [Conclusion] The physiological function and standing stability of the group A subjects were examined at six weeks post training. The results showed that these parameters remained constant. This proved that the proposed system provide substantial support toward the preservation of the Taiwanese older people’ physiological function and standing stability. PMID:27190480

  2. Improvement in the physiological function and standing stability based on kinect multimedia for older people.

    PubMed

    Chen, Chih-Chen

    2016-04-01

    [Purpose] The increase in the Taiwanese older population is associated with age-related inconveniences. Finding adequate and simple physical activities to help the older people maintaining their physiological function and preventing them from falls has become an urgent social issue. [Subjects and Methods] This study aimed to design a virtual exercise training game suitable for Taiwanese older people. This system will allow for the maintenance of the physiological function and standing stability through physical exercise, while using a virtual reality game. The participants can easily exercise in a carefree, interactive environment. This study will use Kinect for Windows for physical movement detection and Unity software for virtual world development. [Results] Group A and B subjects were involved in the exercise training method of Kinect interactive multimedia for 12 weeks. The results showed that the functional reach test and the unipedal stance test improved significantly. [Conclusion] The physiological function and standing stability of the group A subjects were examined at six weeks post training. The results showed that these parameters remained constant. This proved that the proposed system provide substantial support toward the preservation of the Taiwanese older people' physiological function and standing stability. PMID:27190480

  3. Association of exceptional parental longevity and physical function in aging.

    PubMed

    Ayers, Emmeline; Barzilai, Nir; Crandall, Jill P; Milman, Sofiya; Verghese, Joe

    2014-01-01

    Offspring of parents with exceptional longevity (OPEL), who are more likely to carry longevity-associated genotypes, may age more successfully than offspring of parents with usual survival (OPUS). Maintenance of physical function is a key attribute of successful aging. While many genetic and non-genetic factors interact to determine physical phenotype in aging, examination of the contribution of exceptional parental longevity to physical function in aging is limited. The LonGenity study recruited a relatively genetically homogenous cohort of Ashkenazi Jewish (AJ) adults age 65 and older, who were defined as either OPEL (having at least one parent who lived to age 95 or older) or OPUS (neither parent survived to age 95). Subjective and objective measures of physical function were compared between the two groups, accounting for potential confounders. Of the 893 LonGenity subjects, 365 were OPEL and 528 were OPUS. OPEL had better objective and subjective measures of physical function than OPUS, especially on unipedal stance (p = 0.009) and gait speed (p = 0.002). Results support the protective role of exceptional parental longevity in preventing decline in physical function, possibly via genetic mechanisms that should be further explored. PMID:24997018

  4. GALAXIES: SNAPSHOTS IN TIME

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This sequence of NASA Hubble Space Telescope (HST) images of remote galaxies offers tantalizing initial clues to the evolution of galaxies in the universe. [far left column] These are traditional spiral and elliptical-shaped galaxies that make up the two basic classes of island star cities that inhabit the universe we see in our current epoch (14 billion years after the birth of the universe in the Big Bang). Elliptical galaxies contain older stars, while spirals have vigorous ongoing star formation in their dusty, pancake-shaped disks. Our Milky Way galaxy is a typical spiral, or disk-shaped galaxy, on the periphery of the great Virgo cluster. Both galaxies in this column are a few tens of millions of light-years away, and therefore represent our current stage of the universe s evolution. [center left column] These galaxies existed in a rich cluster when the universe was approximately two-thirds its present age. Elliptical galaxies (top) appear fully evolved because they resemble today's descendants. By contrast, some spirals have a frothier appearance, with loosely shaped arms of young star formation. The spiral population appears more disrupted due to a variety of possible dynamical effects that result from dwelling in a dense cluster. [center right column] Distinctive spiral structure appears more vague and disrupted in galaxies that existed when the universe was nearly one-third its present age. These objects do not have the symmetry of current day spirals and contain irregular lumps of starburst activity. However, even this far back toward the beginning of time, the elliptical galaxy (top) is still clearly recognizable. However, the distinction between ellipticals and spirals grows less certain with increasing distance. [far right column] These extremely remote, primeval objects existed with the universe was nearly one-tenth its current age. The distinction between spiral and elliptical galaxies may well disappear at this early epoch. However, the object in the top frame has the light profile of a mature elliptical galaxy. This implies that ellipticals formed remarkably early in the universe while spiral galaxies took much longer to form. Credit: A. Dressler (Carnegie Institutions of Washington), M. Dickinson (STScI), D. Macchetto (ESA/STScI), M. Giavalisco (STScI), and NASA

  5. Are animals stuck in time?

    PubMed

    Roberts, William A

    2002-05-01

    People can time travel cognitively because they can remember events having occurred at particular times in the past (episodic memory) and because they can anticipate new events occurring at particular times in the future. The ability to assign points in time to events arises from human development of a sense of time and its accompanying time-keeping technology. The hypothesis is advanced that animals are cognitively stuck in time: that is, they have no sense of time and thus have no episodic memory or ability to anticipate long-range future events. Research on animals' abilities to detect time of day, track short time intervals, remember the order of a sequence of events, and anticipate future events are considered, and it is concluded that the stuck-in-time hypothesis is largely supported by the current evidence. PMID:12002698

  6. 49 CFR 236.109 - Time releases, timing relays and timing devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES... predetermined time interval, which shall be shown on the plans or marked on the time release, timing relay,...

  7. EDITORIAL: Interesting times

    NASA Astrophysics Data System (ADS)

    Dobson Honorary Editor, Ken

    1996-01-01

    `May you live in interesting times' - old Chinese curse. First, many thanks to John Avison, the retiring Honorary Editor, for his hard work over the last five years, and the steady development in style and content under his stewardship. I can only hope to live up to the standards that he set. The next five years will take us into a new millenium, an event preceded - in England and Wales at least - by a period of stability, reflection and consolidation in education. Or so we are told - but whether such a self-denying ordinance will actually be maintained by the Government both before and after an election in 1997 remains to be seen. Nevertheless, we shall be thankful for any mercies, however small, that permit forward thinking rather than instant response. One of the things that readers of a journal called Physics Education should be thinking about is the continued decline in the numbers of students studying physics post-16. This is not a purely local phenomenon; most European countries are finding a similar decline. There are exceptions, of course: in Scotland numbers studying physics for Highers are increasing. Is such a decline a good thing or a bad thing? Only a minority of post-16 physics students go on to use the bulk of what they have learned in further studies or vocations. Does a knowledge and understanding of physics contribute to the mental well-being and cultural level - let alone material comfort - of any except those who use physics professionally? Is physics defensible as a contribution to the mental armoury of the educated citizen - compared with chemistry, biology - or Latin, say? Or should one rephrase that last question as `Is physics as we teach it today defensible...?' Such questions, and many others no doubt, may well be in the mind of the new Curriculum Officer appointed by the Institute of Physics `to engage in a wide-ranging consultation throughout the entire physics community on the nature and style of post-16 physics programmes, with a view to establishing a major curriculum development exercise on the scale of the Nuffield programmes of the 1960s'. The person appointed in this challenging role is the redoubtable Bryan Chapman (see his letter on page 14). I feel that readers of this journal constitute a well-informed section of the physics community and should be able to make a significant contribution to his work. I intend to use part of the July issue of Physics Education as a forum for views on the nature and style of post-16 (and even relevant pre-l6) physics programmes, both as they are and as they should be. The aim of the forum is not to provide solutions presented in lengthy, fully researched and well-argued articles but to raise ideas (and even expectations), to stimulate debate and set physics educators thinking creatively and radically about what might be an appropriate education in physics for the 2lst century. So send in your views - brief and to the point, trenchant and opinionated (all the more likely to be appreciated by Bryan C), anecdotal and theoretical, but preferably impregnated with the smell of chalk, wet blackboards, the sounds of wobbly-wheeled mechanics trolleys, quietly sizzling resistors and where necessary the heat of close encounters with the National Curriculum (version X) and/or GNVQs and the Subject Core for A-levels. Overseas readers - and Scots - may like to proffer advice based on their own, possibly less rebarbative, experiences. Don't hesitate: there is not a moment to be lost!

  8. Setting Time Limits on Tests

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2011-01-01

    It is shown how the time limit on a test can be set to control the probability of a test taker running out of time before completing it. The probability is derived from the item parameters in the lognormal model for response times. Examples of curves representing the probability of running out of time on a test with given parameters as a function…

  9. Timing Observations of 20 Pulsars

    NASA Astrophysics Data System (ADS)

    Yuan, J.; Li, L.; Liu, Z.; Wang, J.; Wang, N.

    2016-02-01

    Pulse arrival time measurements with the Nanshan 25 m radio telescope have been used to determine timing behaviours for 20 pulsars. We present the timing ephemerides for them, show the timing residual of eight pulsars. In addition we have detected four glitches in five pulsars and provided the glitch parameters.

  10. Real-Time Benchmark Suite

    Energy Science and Technology Software Center (ESTSC)

    1992-01-17

    This software provides a portable benchmark suite for real time kernels. It tests the performance of many of the system calls, as well as the interrupt response time and task response time to interrupts. These numbers provide a baseline for comparing various real-time kernels and hardware platforms.

  11. [Psychological time, definition and challenges].

    PubMed

    Droit-Volet, Sylvie

    2012-10-01

    Psychological time comprises different forms of time. Each form of time corresponds to different psychological mechanisms. The human being is subject to distortions of time under the effect of emotions. The effectiveness of social interaction depends on our aptitude to synchronise ourselves with others. PMID:23167123

  12. Flow of Time: Perceiving the passage of time: neural possibilities

    PubMed Central

    Muller, Timothy; Nobre, Anna C

    2014-01-01

    Although the study of time has been central to physics and philosophy for millennia, questions of how time is represented in the brain and how this representation is related to time perception have only recently started to be addressed. Emerging evidence subtly yet profoundly challenges our intuitive notions of time over short scales, offering insight into the nature of the brain's representation of time. Numerous different models, specified at the neural level, of how the brain may keep track of time have been proposed. These models differ in various ways, such as whether time is represented by a centralized or distributed neural system, or whether there are neural systems dedicated to the problem of timing. This paper reviews the insight offered by behavioral experiments and how these experiments refute and guide some of the various models of the brain's representation of time. PMID:25257798

  13. Time perception and time perspective differences between adolescents and adults.

    PubMed

    Siu, Nicolson Y F; Lam, Heidi H Y; Le, Jacqueline J Y; Przepiorka, Aneta M

    2014-09-01

    The present experiment aimed to investigate the differences in time perception and time perspective between subjects representing two developmental stages, namely adolescence and middle adulthood. Twenty Chinese adolescents aged 15-25 and twenty Chinese adults aged 35-55 participated in the study. A time discrimination task and a time reproduction task were implemented to measure the accuracy of their time perception. The Zimbardo Time Perspective Inventory (Short-Form) was adopted to assess their time orientation. It was found that adolescents performed better than adults in both the time discrimination task and the time reproduction task. Adolescents were able to differentiate different time intervals with greater accuracy and reproduce the target duration more precisely. For the time reproduction task, it was also found that adults tended to overestimate the duration of the target stimuli while adolescents were more likely to underestimate it. As regards time perspective, adults were more future-oriented than adolescents, whereas adolescents were more present-oriented than adults. No significant relationship was found between time perspective and time perception. PMID:25086223

  14. The Length of Time's Arrow

    SciTech Connect

    Feng, Edward H.; Crooks, Gavin E.

    2008-08-21

    An unresolved problem in physics is how the thermodynamic arrow of time arises from an underlying time reversible dynamics. We contribute to this issue by developing a measure of time-symmetry breaking, and by using the work fluctuation relations, we determine the time asymmetry of recent single molecule RNA unfolding experiments. We define time asymmetry as the Jensen-Shannon divergencebetween trajectory probability distributions of an experiment and its time-reversed conjugate. Among other interesting properties, the length of time's arrow bounds the average dissipation and determines the difficulty of accurately estimating free energy differences in nonequilibrium experiments.

  15. Measures of time in astronomy.

    NASA Technical Reports Server (NTRS)

    Mulholland, J. D.

    1972-01-01

    Astronomically-important measures of time are discussed with their definitions, their intended purposes, and areas of viability or obsolescence. Several different kinds of year are defined. Earth rotation time is described in terms of sidereal and solar time and in terms of universal time (UT) for which four different levels are defined corresponding to different approximations of 'uniform' time. The formal definition of ephemeris time, consisting of a defined rate and epoch, is discussed and some unorthodox criticisms are presented. Uses of broadcast time are noted. In the discussion of what measure of time should be used in astronomical applications, it is stated that, at present, all dynamical applications should use a measure of time based on atomic clock time.

  16. Exploring Literacy Coaches' Relationships with Teachers: Balancing Responsive and Directive Coaching Stances

    ERIC Educational Resources Information Center

    Ippolito, Jacy C.

    2009-01-01

    Literacy coaching has become an increasingly popular form of literacy professional development in the United States based on the common assumption that strong relationships between coaches and teachers will drive instructional improvement and gains in student achievement. However, there is little empirical research describing how literacy coaches…

  17. Two Dimensions of an Inquiry Stance toward Student-Learning Data

    ERIC Educational Resources Information Center

    Nelson, Tamara Holmlund; Slavit, David; Deuel, Angie

    2012-01-01

    Background/Context: Schools and districts are increasingly emphasizing evidence-based decision making as a means for improving teaching and learning. In response, professional development efforts have shifted toward situated, sustained activities that involve groups of teachers in reflective inquiry about student learning data, instructional…

  18. Leaving Mango Street: Speech, Action and the Construction of Narrative in Britton's Spectator Stance

    ERIC Educational Resources Information Center

    Crawford-Garrett, Katherine

    2009-01-01

    This paper attempts to unite "The House on Mango Street" by Sandra Cisneros with the participant and spectator theories of James Britton and D. W. Harding in the hopes that such a union will provide new insights into each. In particular, this article explores how the speech acts of Esperanza, the novel's protagonist, are indicative of a shifting…

  19. "By the Rivers of Babylon": Deterritorialization and the Jewish Rhetorical Stance

    ERIC Educational Resources Information Center

    Bernard-Donals, Michael

    2010-01-01

    The position of the excluded other, it seems to the author, is the position that has characterized Jews since antiquity: exiled from the nation and dispersed to other nations, Jewish participation in civic life has been defined, even in modernity, by its marginalization and precariousness. The Jew, in other words, provides a salient example of the…

  20. Keep Your Eyes on the Prize: Critical Stance in the Middle School Classroom

    ERIC Educational Resources Information Center

    Lewison, Mitzi; Heffernan, Lee

    2009-01-01

    This study focuses on ways that sixth graders reacted to the question of book awards and awards in general, positioning themselves as reflective inquirers as they engaged in the regular sixth-grade beginning-of-the-year curriculum--reading books that have been nominated for the state book award. The authors focus on four dispositions of critical…

  1. Taking a Stance through Visual Texts: Novice Teachers as Educational Agents

    ERIC Educational Resources Information Center

    Orland-Barak, Lily; Maskit, Ditza

    2014-01-01

    Drawing on qualitative methodologies that integrate verbal and non-verbal texts, this study investigated novice teachers' attributions of their experiences of internship, as conveyed through a visual text. Novices were invited to design a visual text that represented their experience during internship, as part of a national call entitled

  2. Of risks and regulations: how leading U.S. nanoscientists form policy stances about nanotechnology

    PubMed Central

    Scheufele, Dietram A.; Hu, Qian

    2009-01-01

    Even though there is a high degree of scientific uncertainty about the risks of nanotechnology, many scholars have argued that policy-making cannot be placed on hold until risk assessments are complete (Faunce, Med J Aust 186(4):189–191, 2007; Kuzma, J Nanopart Res 9(1):165–182, 2007; O’Brien and Cummins, Hum Ecol Risk Assess 14(3):568–592, 2008; Powell et al., Environ Manag 42(3):426–443, 2008). In the absence of risk assessment data, decision makers often rely on scientists’ input about risks and regulation to make policy decisions. The research we present here goes beyond the earlier descriptive studies about nanotechnology regulation to explore the heuristics that the leading U.S. nanoscientists use when they make policy decisions about regulating nanotechnology. In particular, we explore the relationship between nanoscientists’ risk and benefit perceptions and their support for nanotech regulation. We conclude that nanoscientists are more supportive of regulating nanotechnology when they perceive higher levels of risks; yet, their perceived benefits about nanotechnology do not significantly impact their support for nanotech regulation. We also find some gender and disciplinary differences among the nanoscientists. Males are less supportive of nanotech regulation than their female peers and materials scientists are more supportive of nanotechnology regulation than scientists in other fields. Lastly, our findings illustrate that the leading U.S. nanoscientists see the areas of surveillance/privacy, human enhancement, medicine, and environment as the nanotech application areas that are most in need of new regulations. PMID:21170136

  3. Effects of asymmetrical stance and movement on body rotation in pushing.

    PubMed

    Lee, Yun-Ju; Aruin, Alexander S

    2015-01-21

    Pushing objects in the presence of body asymmetries could increase the risk of back injury. Furthermore, when the object is heavy, it could exacerbate the effects induced by asymmetrical posture. We investigated how the use of asymmetrical posture and/or upper extremity movement affect vertical torque (Tz) and center of pressure (COP) displacement during pushing. Ten healthy volunteers were instructed to push objects of three different weights using two hands (symmetrical hand use) or one hand (asymmetrical hand use) while standing in symmetrical or asymmetrical foot-positions. The peak values of Tz and COP displacement in the medial-lateral direction (COPML) were analyzed. In cases of isolated asymmetry, changes in the Tz were mainly linked with effects of hand-use whereas effects of foot-position dominated changes in the COPML displacement. In cases of a combined asymmetry, the magnitudes of both Tz and COPML were additive when asymmetrical hand-use and foot-position induced the rotation of the lower and upper body in the same direction or subtractive when asymmetries resulted in the rotation of the body segments in the opposite directions. Moreover, larger Tz and COP displacements were seen when pushing the heavy weight. The results point out the importance of using Tz and COPML to describe the isolated or combined effects of asymmetrical upper extremity movement and asymmetrical posture on body rotation during pushing. Furthermore, it suggests that a proper combination of unilateral arm movement and foot placements could help to reduce body rotation even when pushing heavy objects. PMID:25498915

  4. Socializing Children to Honorifics in Japanese: Identity and Stance in Interaction

    ERIC Educational Resources Information Center

    Burdelski, Matthew

    2013-01-01

    This paper examines socialization of honorifics in Japanese. Drawing upon audiovisual recordings of interaction in households and a preschool, the paper details ways caregivers use honorifics with children and ways children use honorifics with caregivers and peers. The analysis shows ways caregivers use referent and addressee honorifics within…

  5. Taking a Stance: Child Agency across the Dimensions of Early Adolescents' Environmental Involvement

    ERIC Educational Resources Information Center

    Blanchet-Cohen, Natasha

    2008-01-01

    This article examines the nature of early adolescents' environmental involvement based on a study with 10-13-year-olds. Drawing from literal and metaphorical interviews, a visual survey and visual maps, the study points to the dimensions of environmental involvement: connectedness, engagement with the environment, questioning, belief in capacity,…

  6. "Does Broca's Area Exist?:" Christofredo Jakob's 1906 Response to Pierre Marie's Holistic Stance

    ERIC Educational Resources Information Center

    Tsapkini, Kyrana; Vivas, Ana B.; Triarhou, Lazaros C.

    2008-01-01

    In 1906, Pierre Marie triggered a heated controversy and an exchange of articles with Jules Dejerine over the localization of language functions in the human brain. The debate spread internationally. One of the timeliest responses, that appeared in print 1 month after Marie's paper, came from Christofredo Jakob, a Bavarian-born neuropathologist…

  7. Lexical Bundle Analysis in Mathematics Classroom Discourse: The Significance of Stance

    ERIC Educational Resources Information Center

    Herbel-Eisenmann, Beth; Wagner, David; Cortes, Viviana

    2010-01-01

    In this article, we introduce the lexical bundle, defined by corpus linguists as a group of three or more words that frequently recur together, in a single group, in a particular register (Biber, Johansson, Leech, Conrad, & Finegan, 2006; Cortes, "English for Specific Purposes" 23:397-423, 2004). Attention to lexical bundles helps to explore…

  8. A Group of Educators' Stance on the Implementation of South Africa's Further Education and Training Curriculum

    ERIC Educational Resources Information Center

    Treu, P.; Olivier, M. A. J.; Bean, P.; Van der Walt, J. L.

    2010-01-01

    In their dealings with educators in the Southern Cape region of South Africa, the researchers observed among them a degree of negativity and pessimism about the implementation of the Further Education and Training (FET) policy and curriculum during 2006. Exploratory discussions supported the surmise that a gap existed between policy formulation

  9. Redefining Online Discussions: Using Participant Stances to Promote Collaboration and Cognitive Engagement

    ERIC Educational Resources Information Center

    Putman, S. Michael; Ford, Karen; Tancock, Susan

    2012-01-01

    Advances in technology are having a profound impact on distance education as online learning is becoming a preferred educational option. Within these online learning experiences, the asynchronous online discussion has evolved into one of the most commonly used communication tools. However, a lack of cognitive processing and interaction in the…

  10. Teachers' Emerging Stances and Repertoires towards Reconciliation: Potential and Challenges in Greek-Cypriot Education

    ERIC Educational Resources Information Center

    Zembylas, Michalinos; Charalambous, Panayiota; Charalambous, Constadina

    2011-01-01

    In this paper we examine Greek-Cypriot teachers' positions towards the--largely unfamiliar--concept of reconciliation within the Greek-Cypriot community. Looking at a set of 40 interviews conducted in spring 2009, this study is set against the broader historical context of the continuing Cyprus Problem and the development of ethnic rivalry between…

  11. Teachers' Stances on Cell Phones in the ESL Classroom: Toward a "Theoretical" Framework

    ERIC Educational Resources Information Center

    Brown, Jeff

    2014-01-01

    In the ongoing and constantly expanding discussion surrounding cell phones in the classroom, a theoretical complement to the practical side of the issue is generally lacking. This is perhaps understandable. Many teachers are still trying to deal with the simple presence of cell phones in the class, and managing a classroom in which the presence…

  12. Measuring the Institutional Stance on Matters of Student Conduct. CSE Report No. 55.

    ERIC Educational Resources Information Center

    Seligman, Richard

    This study is concerned with the initial testing of an instrument which examines student discipline in terms of four areas: goals and objectives of the discipline program, scope of the program, procedures and sanctions. This investigation by the Center for the Study of Evaluation has been undertaken as part of the Higher Education Evaluation…

  13. Becoming, Being and Having Been: Practitioner Perspectives on Temporal Stances and Participation across Children's Services

    ERIC Educational Resources Information Center

    Cross, Beth

    2011-01-01

    This article is based on a study of the changing meanings and experiences of citizenship and participation for young people in transition from primary to secondary school. One of the primary concerns of the study is to better understand how different professional practices impact upon young people's uptake of participation and adoption of civic…

  14. Taking an Investigative Stance in Using the Professional Standards in the Languages Classroom

    ERIC Educational Resources Information Center

    Farmer, Kylie

    2009-01-01

    The Professional Standards Project (PSP) is a nationally coordinated professional learning program for languages teachers, to improve the quality of languages teaching and, thereby, improve student learning. It is based on the use of the "Professional standards for accomplished teaching of languages and cultures" (hereafter, "the Standards") as a…

  15. Creating a Contrastive Rhetorical Stance: Investigating the Strategy of Problematization in Students' Argumentation

    ERIC Educational Resources Information Center

    Mei, Wu Siew

    2006-01-01

    It is often the case that undergraduates writing essays to fulfil course requirements have an academic audience (i.e. lecturer/s marking the essay) as their target readers. These texts may represent a form of academic writing by novice writers in the process of learning academic discourse and conventions. Though these texts may not be comparable…

  16. Exploring Literacy Coaches' Relationships with Teachers: Balancing Responsive and Directive Coaching Stances

    ERIC Educational Resources Information Center

    Ippolito, Jacy C.

    2009-01-01

    Literacy coaching has become an increasingly popular form of literacy professional development in the United States based on the common assumption that strong relationships between coaches and teachers will drive instructional improvement and gains in student achievement. However, there is little empirical research describing how literacy coaches

  17. Developing Inquiry-as-Stance and Repertoires of Practice: Teacher Learning across Two Settings

    ERIC Educational Resources Information Center

    Braaten, Melissa L.

    2011-01-01

    Sixteen science educators joined a science teacher video club for one school year to collaboratively inquire into each other's classroom practice through the use of records of practice including classroom video clips and samples of student work. This group was focused on developing ambitious, equitable science teaching that capitalizes on

  18. Taking a Stance through Visual Texts: Novice Teachers as Educational Agents

    ERIC Educational Resources Information Center

    Orland-Barak, Lily; Maskit, Ditza

    2014-01-01

    Drawing on qualitative methodologies that integrate verbal and non-verbal texts, this study investigated novice teachers' attributions of their experiences of internship, as conveyed through a visual text. Novices were invited to design a visual text that represented their experience during internship, as part of a national call entitled…

  19. Posture-movement responses to stance perturbations and upper limb fatigue during a repetitive pointing task.

    PubMed

    Fuller, Jason R; Fung, Joyce; Côté, Julie N

    2013-08-01

    Localized muscle fatigue and postural perturbation have separately been shown to alter whole-body movement but little is known about how humans respond when subjected to both factors combined. Here we sought to quantify the kinematics of postural control and repetitive upper limb movement during standing surface perturbations and in the presence of fatigue. Subjects stood on a motion-based platform and repetitively reached between two shoulder-height targets until noticeably fatigued (rating of perceived exertion=8/10). Every minute, subjects experienced a posterior and an anterior platform translation while reaching to the distal target. Outcomes were compared prior to and with fatigue (first vs. final minute data). When fatigued, regardless of the perturbation condition, subjects decreased their shoulder abduction and increased contralateral trunk flexion, a strategy that may relieve the load on the fatiguing upper limb musculature. During perturbations, kinematic adaptations emerged across the trunk and arm to preserve task performance. In contrast to our expectation, the kinematic response to the perturbations did not alter in the presence of fatigue. Kinematic adaptations in response to the perturbation predominantly occurred in the direction of the reach whereas fatigue adaptations occurred orthogonal to the reach. These findings suggest that during repetitive reaching, fatigue and postural perturbation compensations organize so as to minimize interaction with each other and preserve the global task characteristics of endpoint motion. PMID:24054899

  20. Emotions in the Cross-Fire: Structuralist vs. Post-Structuralist Stances in Bilingualism Research

    ERIC Educational Resources Information Center

    Kramsch, Claire

    2008-01-01

    What Aneta Pavlenko discusses in this fascinating article is so widely researched, so cogently conceptualized and so richly reflected upon, that one feels like a spoilsport to bring up a debate which the author herself claims to have avoided, namely the "universalist/relativist debate about basic emotions". If I do so in this Commentary, it is not…