WorldWideScience

Sample records for force override rate

  1. Three Axis Force Override Rate Control of a PUMA 560 Manipulator

    Science.gov (United States)

    1993-03-01

    and Intelligence, p. 242, McGraw-Hill, New York, 1987. 8. Whitney, D.E., "Historical Perspective and State of the Art in Robot Force Control ," Proceedings... Force Control ," Proceedings of the IEEE Conference on Robotics and Automation, (1987), pp.904-909. 12. Syvertsen, J. M., Force Override Rate...the IEEE Conference on Robotics and Automation, (1989), p. 102. 110 11. Eppinger, S.D., and Seering, W.P., "Understanding Bandwidth Limitations in Robot

  2. Drug Interaction Alert Override Rates in the Meaningful Use Era

    Science.gov (United States)

    Bryant, A.D.; Fletcher, G.S.

    2014-01-01

    Summary Background Interruptive drug interaction alerts may reduce adverse drug events and are required for Stage I Meaningful Use attestation. For the last decade override rates have been very high. Despite their widespread use in commercial EHR systems, previously described interventions to improve alert frequency and acceptance have not been well studied. Objectives (1) To measure override rates of inpatient medication alerts within a commercial clinical decision support system, and assess the impact of local customization efforts. (2) To compare override rates between drug-drug interaction and drug-allergy interaction alerts, between attending and resident physicians, and between public and academic hospitals. (3) To measure the correlation between physicians’ individual alert quantities and override rates as an indicator of potential alert fatigue. Methods We retrospectively analyzed physician responses to drug-drug and drug-allergy interaction alerts, as generated by a common decision support product in a large teaching hospital system. Results (1) Over four days, 461 different physicians entered 18,354 medication orders, resulting in 2,455 visible alerts; 2,280 alerts (93%) were overridden. (2) The drug-drug alert override rate was 95.1%, statistically higher than the rate for drug-allergy alerts (90.9%) (p < 0.001). There was no significant difference in override rates between attendings and residents, or between hospitals. (3) Physicians saw a mean of 1.3 alerts per day, and the number of alerts per physician was not significantly correlated with override rate (R2 = 0.03, p = 0.41). Conclusions Despite intensive efforts to improve a commercial drug interaction alert system and to reduce alerting, override rates remain as high as reported over a decade ago. Alert fatigue does not seem to contribute. The results suggest the need to fundamentally question the premises of drug interaction alert systems. PMID:25298818

  3. Drug interaction alert override rates in the Meaningful Use era: no evidence of progress.

    Science.gov (United States)

    Bryant, A D; Fletcher, G S; Payne, T H

    2014-01-01

    Interruptive drug interaction alerts may reduce adverse drug events and are required for Stage I Meaningful Use attestation. For the last decade override rates have been very high. Despite their widespread use in commercial EHR systems, previously described interventions to improve alert frequency and acceptance have not been well studied. (1) To measure override rates of inpatient medication alerts within a commercial clinical decision support system, and assess the impact of local customization efforts. (2) To compare override rates between drug-drug interaction and drug-allergy interaction alerts, between attending and resident physicians, and between public and academic hospitals. (3) To measure the correlation between physicians' individual alert quantities and override rates as an indicator of potential alert fatigue. We retrospectively analyzed physician responses to drug-drug and drug-allergy interaction alerts, as generated by a common decision support product in a large teaching hospital system. (1) Over four days, 461 different physicians entered 18,354 medication orders, resulting in 2,455 visible alerts; 2,280 alerts (93%) were overridden. (2) The drug-drug alert override rate was 95.1%, statistically higher than the rate for drug-allergy alerts (90.9%) (p < 0.001). There was no significant difference in override rates between attendings and residents, or between hospitals. (3) Physicians saw a mean of 1.3 alerts per day, and the number of alerts per physician was not significantly correlated with override rate (R2 = 0.03, p = 0.41). Despite intensive efforts to improve a commercial drug interaction alert system and to reduce alerting, override rates remain as high as reported over a decade ago. Alert fatigue does not seem to contribute. The results suggest the need to fundamentally question the premises of drug interaction alert systems.

  4. High Override Rate for Opioid Drug-allergy Interaction Alerts: Current Trends and Recommendations for Future.

    Science.gov (United States)

    Topaz, Maxim; Seger, Diane L; Lai, Kenneth; Wickner, Paige G; Goss, Foster; Dhopeshwarkar, Neil; Chang, Frank; Bates, David W; Zhou, Li

    2015-01-01

    This study examined trends in drug-allergy interaction (DAI) alert overrides for opioid medications - the most commonly triggered alerts in the computerized provider order entry (CPOE). We conducted an observational analysis of the DAI opioid alerts triggered over the last decade (2004-2013, n=342,338) in two large academic hospitals in Boston (United States). We found an increasing rate of DAI alert overrides culminating in 89.7% in 2013. Allergic reactions included a high proportion (38.2%) of non-immune mediated opioid reactions (e.g. gastrointestinal upset). The DAI alert override rate was high for immune mediated (88.6%) and life threatening reactions (87.8%). Exact allergy-medication matches were overridden less frequently (about 70%) compared to non-exact matches within allergy groups (over 90%). About one-third of the alert override reasons pointed to irrelevant alerts (i.e."Patient has tolerated the medication before") and 44.9% were unknown. Those findings warrant further investigation into providers' reasons for high override rate. User interfaces should evolve to enable less interruptive and more accurate alerts to decrease alert fatigue.

  5. Labor Force Participation Rate

    Data.gov (United States)

    City and County of Durham, North Carolina — This thematic map presents the labor force participation rate of working-age people in the United States in 2010. The 2010 Labor Force Participation Rate shows the...

  6. Rate of force development

    DEFF Research Database (Denmark)

    Maffiuletti, Nicola A; Aagaard, Per; Blazevich, Anthony J

    2016-01-01

    The evaluation of rate of force development during rapid contractions has recently become quite popular for characterising explosive strength of athletes, elderly individuals and patients. The main aims of this narrative review are to describe the neuromuscular determinants of rate of force...... development and to discuss various methodological considerations inherent to its evaluation for research and clinical purposes. Rate of force development (1) seems to be mainly determined by the capacity to produce maximal voluntary activation in the early phase of an explosive contraction (first 50-75 ms......), particularly as a result of increased motor unit discharge rate; (2) can be improved by both explosive-type and heavy-resistance strength training in different subject populations, mainly through an improvement in rapid muscle activation; (3) is quite difficult to evaluate in a valid and reliable way...

  7. Overriding Faulty Circuit Breakers

    Science.gov (United States)

    Robbins, Richard L.; Pierson, Thomas E.

    1987-01-01

    Retainer keeps power on in emergency. Simple mechanical device attaches to failed aircraft-type push/pull circuit breaker to restore electrical power temporarily until breaker replaced. Device holds push/pull button in closed position; unnecessary for crewmember to hold button in position by continual finger pressure. Sleeve and plug hold button in, overriding mechanical failure in circuit breaker. Windows in sleeve show button position.

  8. 3D Thermochemical Numerical Model of a Convergent Zone With an Overriding Plate

    Science.gov (United States)

    Mason, W. G.; Moresi, L.; Betts, P. G.

    2008-12-01

    We have created a new three dimensional thermochemical numerical model of a convergent zone, in which a viscoplastic oceanic plate subducts beneath a viscous overriding plate, using the finite element Geoscience research code Underworld. Subduction is initiated by mantle flow induced by the gravitational instability of a slab tip, and buoyancy of the overriding plate. A cold thermal boundary layer envelopes both plates, and is partially dragged into the mantle along with the subducting slab. The trench rolls back as the slab subducts, and the overriding plate follows the retreating trench without being entrained into the upper mantle. The model is repeated with the overriding plate excluded, to analyse the influence of the overriding plate. The overriding plate retards the rate of subduction. Maximum strain rates, evident along the trench in the absence of an overriding plate, extend to a greater depth within the subducted portion of the slab in the presence of an overriding plate.

  9. Overriding information issues. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hein, Vibeke

    1998-04-01

    The Nordic project on overriding information issues focus on why an information project, how to inform about a difficult subject in a modern society, how to provide advance information, how to inform when the accident has occurred and how to inform about NKS and projects. (au)

  10. Early and Late Rate of Force Development

    DEFF Research Database (Denmark)

    Andersen, Lars L; Andersen, Jesper L; Zebis, Mette K

    2010-01-01

    The objective of this study is to investigate the potentially opposing influence of qualitative and quantitative muscular adaptations in response to high-intensity resistance training on contractile rate of force development (RFD) in the early (200 ms) of rising muscle force. Fifteen healthy young...... the vastus lateralis. The main findings were that RFD in the late phase of rising muscle force increased in response to resistance training whereas early RFD remained unchanged and early relative RFD (i.e., RFD/MVC) decreased. Quantitatively, muscle fiber cross-sectional area and MVC increased whereas......-intensity resistance training due to differential influences of qualitative and quantitative muscular adaptations on early and later phases of rising muscle force....

  11. Relations between plate kinematics, slab geometry and overriding plate deformation in subduction zones: insights from statistical observations and laboratory modelling

    Science.gov (United States)

    Heuret, A.; Funiciello, F.; Faccenna, C.; Lallemand, S.

    2005-12-01

    3-D laboratory models have been performed in order to investigate the way plates kinematics (subducting and overriding plate absolute motions and the resulting plate convergence rate) influences the geometry of the slab and the overriding plate deformation in subduction zones. In the experiments a viscous plate of silicone (subducting plate) is pushed beneath another plate, which is itself pushed toward or pulled away from the trench (overriding plate), and sinks into a viscous layer of glucose syrup (upper mantle). The subducting and overriding plate velocities explored the variability field of natural subduction plates kinematics. The overriding plate motion exerts a primary role in the control of slab geometries and overriding plate deformation rates. The experiments have revealed two different subduction behaviours: (Style I) the overriding plate moves toward the trench and shortens at high rates, the slab is flat and deflected when reaching the bottom of the box in a forward direction; (Style II) the overriding plates moves away from the trench and shortens at low rates the slab is steep and deflected on the box bottom in a backward direction. To a lesser extent, increasing subducting plate motion is associated to increasing slab dips and overriding plate shortening. Slab geometry and overriding plate deformation are less sensitive to the overall plate convergence rate. These laboratory models behaviours are consistent with statistical analysis performed on natural subduction zones, and enlighten the first order control exerted by the overriding plate absolute motion, on the geometry adopted by the slab and the way the overriding plate deforms.

  12. A Video Recall Study of In-session Changes in Sentiment Override.

    Science.gov (United States)

    Johnson, Lee N; Tambling, Rachel B; Anderson, Shayne R

    2015-09-01

    This study examines in-session changes in sentiment override over the first three sessions of couple therapy. Couples viewed a video recording of therapy sessions immediately after each of the first three sessions and continuously rated their level of sentiment override. Ninety-eight changes were randomly chosen for analysis. Three talk turns prior to each change was coded using the Family Relational Communication Control Coding System. Results show that changes in sentiment override occur frequently. Repeated incidents of communication control were related to negative change in sentiment override for females. Repeated incidents of being left out of the conversation were related to negative changes in sentiment override for females and positive changes for males. © 2014 Family Process Institute.

  13. Specific cerebellar regions are related to force amplitude and rate of force development.

    Science.gov (United States)

    Spraker, M B; Corcos, D M; Kurani, A S; Prodoehl, J; Swinnen, S P; Vaillancourt, D E

    2012-01-16

    The human cerebellum has been implicated in the control of a wide variety of motor control parameters, such as force amplitude, movement extent, and movement velocity. These parameters often covary in both movement and isometric force production tasks, so it is difficult to resolve whether specific regions of the cerebellum relate to specific parameters. In order to address this issue, the current study used two experiments and SUIT normalization to determine whether BOLD activation in the cerebellum scales with the amplitude or rate of change of isometric force production or both. In the first experiment, subjects produced isometric pinch-grip force over a range of force amplitudes without any constraints on the rate of force development. In the second experiment, subjects varied the rate of force production, but the target force amplitude remained constant. The data demonstrate that BOLD activation in separate sub-areas of cerebellar regions lobule VI and Crus I/II scales with both force amplitude and force rate. In addition, BOLD activation in cerebellar lobule V and vermis VI was specific to force amplitude, whereas BOLD activation in lobule VIIb was specific to force rate. Overall, cerebellar activity related to force amplitude was located superior and medial, whereas activity related to force rate was inferior and lateral. These findings suggest that specific circuitry in the cerebellum may be dedicated to specific motor control parameters such as force amplitude and force rate.

  14. A thermo-mechanical model of horizontal subduction below an overriding plate

    NARCIS (Netherlands)

    Hunen, Jeroen van; Berg, A.P. van den; Vlaar, N.J.

    2000-01-01

    Subduction of young oceanic lithosphere cannot be explained by the gravitational driving mechanisms of slab pull and ridge push. This deficiency of driving forces can be overcome by obduction of an actively overriding plate, which forces the young plate either to subduct or to collide. This

  15. A thermo-mechanical model of horizontal subduction below an overriding plate

    NARCIS (Netherlands)

    Hunen, Jeroen van; Berg, A.P. van den; Vlaar, N.J.

    2001-01-01

    Subduction of young oceanic lithosphere cannot be explained by the gravitational driving mechanisms of slab pull and ridge push. This deficiency of driving forces can be overcome by obduction of an actively overriding plate, which forces the young plate either to subduct or to collide. This mechanis

  16. Neuromuscular rate of force development deficit in Parkinson disease.

    Science.gov (United States)

    Hammond, Kelley G; Pfeiffer, Ronald F; LeDoux, Mark S; Schilling, Brian K

    2017-06-01

    Bradykinesia and reduced neuromuscular force exist in Parkinson disease. The interpolated twitch technique has been used to evaluate central versus peripheral manifestations of neuromuscular strength in healthy, aging, and athletic populations, as well as moderate to advanced Parkinson disease, but this method has not been used in mild Parkinson disease. This study aimed to evaluate quadriceps femoris rate of force development and quantify potential central and peripheral activation deficits in individuals with Parkinson disease. Nine persons with mild Parkinson Disease (Hoehn & Yahr≤2, Unified Parkinson Disease Rating Scale total score=mean 19.1 (SD 5.0)) and eight age-matched controls were recruited in a cross-sectional investigation. Quadriceps femoris voluntary and stimulated maximal force and rate of force development were evaluated using the interpolated twitch technique. Thirteen participants satisfactorily completed the protocol. Individuals with early Parkinson disease (n=7) had significantly slower voluntary rate of force development (p=0.008; d=1.97) and rate of force development ratio (p=0.004; d=2.18) than controls (n=6). No significant differences were found between groups for all other variables. Persons with mild-to-moderate Parkinson disease display disparities in rate of force development, even without deficits in maximal force. The inability to produce force at a rate comparable to controls is likely a downstream effect of central dysfunction of the motor pathway in Parkinson disease. Copyright © 2017. Published by Elsevier Ltd.

  17. Unilateral arm strength training improves contralateral peak force and rate of force development.

    Science.gov (United States)

    Adamson, Michael; Macquaide, Niall; Helgerud, Jan; Hoff, Jan; Kemi, Ole Johan

    2008-07-01

    Neural adaptation following maximal strength training improves the ability to rapidly develop force. Unilateral strength training also leads to contralateral strength improvement, due to cross-over effects. However, adaptations in the rate of force development and peak force in the contralateral untrained arm after one-arm training have not been determined. Therefore, we aimed to detect contralateral effects of unilateral maximal strength training on rate of force development and peak force. Ten adult females enrolled in a 2-month strength training program focusing of maximal mobilization of force against near-maximal load in one arm, by attempting to move the given load as fast as possible. The other arm remained untrained. The training program did not induce any observable hypertrophy of any arms, as measured by anthropometry. Nevertheless, rate of force development improved in the trained arm during contractions against both submaximal and maximal loads by 40-60%. The untrained arm also improved rate of force development by the same magnitude. Peak force only improved during a maximal isometric contraction by 37% in the trained arm and 35% in the untrained arm. One repetition maximum improved by 79% in the trained arm and 9% in the untrained arm. Therefore, one-arm maximal strength training focusing on maximal mobilization of force increased rapid force development and one repetition maximal strength in the contralateral untrained arm. This suggests an increased central drive that also crosses over to the contralateral side.

  18. Rate of force development: physiological and methodological considerations.

    Science.gov (United States)

    Maffiuletti, Nicola A; Aagaard, Per; Blazevich, Anthony J; Folland, Jonathan; Tillin, Neale; Duchateau, Jacques

    2016-06-01

    The evaluation of rate of force development during rapid contractions has recently become quite popular for characterising explosive strength of athletes, elderly individuals and patients. The main aims of this narrative review are to describe the neuromuscular determinants of rate of force development and to discuss various methodological considerations inherent to its evaluation for research and clinical purposes. Rate of force development (1) seems to be mainly determined by the capacity to produce maximal voluntary activation in the early phase of an explosive contraction (first 50-75 ms), particularly as a result of increased motor unit discharge rate; (2) can be improved by both explosive-type and heavy-resistance strength training in different subject populations, mainly through an improvement in rapid muscle activation; (3) is quite difficult to evaluate in a valid and reliable way. Therefore, we provide evidence-based practical recommendations for rational quantification of rate of force development in both laboratory and clinical settings.

  19. OPTIMAL CONVERGENCE RATE OF THE LANDAU EQUATION WITH FRICTIONAL FORCE

    Institute of Scientific and Technical Information of China (English)

    Liu Shuangqian; Liu Hongxia

    2012-01-01

    The Cauchy problem of the Landau equation with frictional force is investigated.Based on Fourier analysis and nonlinear energy estimates,the optimal convergence rate to the steady state is obtained under some conditions on initial data.

  20. Interaction of Rate of Force Development and Duration of Rate in Isometric Force.

    Science.gov (United States)

    Siegel, Donald

    A study attempted to determine whether force and duration parameters are programmed in an interactive or independent fashion prior to executing ballistic type isometric contractions of graded intensities. Four adult females each performed 360 trials of producing ballistic type forces representing 25, 40, 55, and 75 percent of their maximal…

  1. The relationship of motor unit size, firing rate and force.

    Science.gov (United States)

    Conwit, R A; Stashuk, D; Tracy, B; McHugh, M; Brown, W F; Metter, E J

    1999-07-01

    Using a clinical electromyographic (EMG) protocol, motor units were sampled from the quadriceps femoris during isometric contractions at fixed force levels to examine how average motor unit size and firing rate relate to force generation. Mean firing rates (mFRs) and sizes (mean surface-detected motor unit action potential (mS-MUAP) area) of samples of active motor units were assessed at various force levels in 79 subjects. MS-MUAP size increased linearly with increased force generation, while mFR remained relatively constant up to 30% of a maximal force and increased appreciably only at higher force levels. A relationship was found between muscle force and mS-MUAP area (r2 = 0.67), mFR (r2 = 0.38), and the product of mS-MUAP area and mFR (mS-MUAP x mFR) (r2 = 0.70). The results support the hypothesis that motor units are recruited in an orderly manner during forceful contractions, and that in large muscles only at higher levels of contraction ( > 30% MVC) do mFRs increase appreciably. MS-MUAP and mFR can be assessed using clinical EMG techniques and they may provide a physiological basis for analyzing the role of motor units during muscle force generation.

  2. Two dimensional eye tracking: Sampling rate of forcing function

    Science.gov (United States)

    Hornseth, J. P.; Monk, D. L.; Porterfield, J. L.; Mcmurry, R. L.

    1978-01-01

    A study was conducted to determine the minimum update rate of a forcing function display required for the operator to approximate the tracking performance obtained on a continuous display. In this study, frequency analysis was used to determine whether there was an associated change in the transfer function characteristics of the operator. It was expected that as the forcing function display update rate was reduced, from 120 to 15 samples per second, the operator's response to the high frequency components of the forcing function would show a decrease in gain, an increase in phase lag, and a decrease in coherence.

  3. Quantifying plyometric intensity via rate of force development, knee joint, and ground reaction forces.

    Science.gov (United States)

    Jensen, Randall L; Ebben, William P

    2007-08-01

    Because the intensity of plyometric exercises usually is based simply upon anecdotal recommendations rather than empirical evidence, this study sought to quantify a variety of these exercises based on forces placed upon the knee. Six National Collegiate Athletic Association Division I athletes who routinely trained with plyometric exercises performed depth jumps from 46 and 61 cm, a pike jump, tuck jump, single-leg jump, countermovement jump, squat jump, and a squat jump holding dumbbells equal to 30% of 1 repetition maximum (RM). Ground reaction forces obtained via an AMTI force plate and video analysis of markers placed on the left hip, knee, lateral malleolus, and fifth metatarsal were used to estimate rate of eccentric force development (E-RFD), peak ground reaction forces (GRF), ground reaction forces relative to body weight (GRF/BW), knee joint reaction forces (K-JRF), and knee joint reaction forces relative to body weight (K-JRF/BW) for each plyometric exercise. One-way repeated measures analysis of variance indicated that E-RFD, K-JRF, and K-JRF/BW were different across the conditions (p 0.05). Results indicate that there are quantitative differences between plyometric exercises in the rate of force development during landing and the forces placed on the knee, though peak GRF forces associated with landing may not differ.

  4. Override of spontaneous respiratory pattern generator reduces cardiovascular parasympathetic influence

    Science.gov (United States)

    Patwardhan, A. R.; Vallurupalli, S.; Evans, J. M.; Bruce, E. N.; Knapp, C. F.

    1995-01-01

    We investigated the effects of voluntary control of breathing on autonomic function in cardiovascular regulation. Variability in heart rate was compared between 5 min of spontaneous and controlled breathing. During controlled breathing, for 5 min, subjects voluntarily reproduced their own spontaneous breathing pattern (both rate and volume on a breath-by-breath basis). With the use of this experimental design, we could unmask the effects of voluntary override of the spontaneous respiratory pattern generator on autonomic function in cardiovascular regulation without the confounding effects of altered respiratory pattern. Results from 10 subjects showed that during voluntary control of breathing, mean values of heart rate and blood pressure increased, whereas fractal and spectral powers in heart rate in the respiratory frequency region decreased. End-tidal PCO2 was similar during spontaneous and controlled breathing. These results indicate that the act of voluntary control of breathing decreases the influence of the vagal component, which is the principal parasympathetic influence in cardiovascular regulation.

  5. Labour Force Participation Rates of Older Persons: An International Comparison.

    Science.gov (United States)

    Clark, Robert L.; Anker, Richard

    1990-01-01

    Using data from 151 countries, labor force participation of older men and women was analyzed and related to economic, demographic, and policy variables. Reduced participation rates are related to increased income levels, structural changes, social security programs, and, for men, the ratio of older persons to persons of standard working age. (SK)

  6. Effect of combined variation of force amplitude and rate of force development on the modulation characteristics of muscle activation during rapid isometric aiming force production.

    Science.gov (United States)

    Park, Jin-Hoon; Stelmach, George E

    2006-01-01

    Studies of rapid target-directed limb movements have suggested that various control schemes can be defined by the modulation pattern of the muscle activity. The present study was aimed to address the question regarding the extent to which a simultaneous control of force amplitude, and rate of force development influences the modulation characteristics of muscle activation associated with producing rapid isometric aiming forces at the elbow joint. The subjects were instructed to produce rapid isometric force pulses to three different force amplitudes (15, 35, and 55% of their maximal voluntary contractions) under systematically varied force-rate conditions ranging from a fast and accurate force-rate to the fastest force-rate possible. The results showed that larger force amplitudes were achieved by increasing the rate of force development (d F/d t) while the time to peak force remained relatively constant. The magnitude of the electromyographic (EMG) burst systematically increased as a function of force amplitude at all force-rate conditions. The primary finding was that the characteristic of the EMG burst duration associated with different force amplitudes showed a significant difference among force-rate conditions. Under a fast and accurate force-rate condition, the duration of the agonist burst increased linearly with force amplitude. A gradual transition into a fixed duration of the agonist burst then was observed over the remaining three force-rate requirements. With increasingly faster force-rates, there were no changes in the agonist burst duration over three force amplitudes. These results indicate that the combined variations in force amplitude and force-rate examined relative to the most rapid force-rate influence the control patterns for the muscle activation during the fast isometric force production. Changes in the EMG modulation patterns observed are likely due to the constraints imposed by muscle contractile properties.

  7. An Improved Steam Injection Model with the Consideration of Steam Override

    Directory of Open Access Journals (Sweden)

    He Congge

    2017-01-01

    Full Text Available The great difference in density between steam and liquid during wet steam injection always results in steam override, that is, steam gathers on the top of the pay zone. In this article, the equation for steam override coefficient was firstly established based on van Lookeren’s steam override theory and then radius of steam zone and hot fluid zone were derived according to a more realistic temperature distribution and an energy balance in the pay zone. On this basis, the equation for the reservoir heat efficiency with the consideration of steam override was developed. Next, predicted results of the new model were compared with these of another analytical model and CMG STARS (a mature commercial reservoir numerical simulator to verify the accuracy of the new mathematical model. Finally, based on the validated model, we analyzed the effects of injection rate, steam quality and reservoir thickness on the reservoir heat efficiency. The results show that the new model can be simplified to the classic model (Marx-Langenheim model under the condition of the steam override being not taken into account, which means the Marx-Langenheim model is corresponding to a special case of this new model. The new model is much closer to the actual situation compared to the Marx-Langenheim model because of considering steam override. Moreover, with the help of the new model, it is found that the reservoir heat efficiency is not much affected by injection rate and steam quality but significantly influenced by reservoir thickness, and to ensure that the reservoir can be heated effectively, the reservoir thickness should not be too small.

  8. Fatigue-induced dissociation between rate of force development and maximal force across repeated rapid contractions.

    Science.gov (United States)

    Boccia, Gennaro; Dardanello, Davide; Tarperi, Cantor; Festa, Luca; La Torre, Antonio; Pellegrini, Barbara; Schena, Federico; Rainoldi, Alberto

    2017-08-01

    We examined whether the presence of fatigue induced by prolonged running influenced the time courses of force generating capacities throughout a series of intermittent rapid contractions. Thirteen male amateur runners performed a set of 15 intermittent isometric rapid contractions of the knee extensor muscles, (3s/5s on/off) the day before (PRE) and immediately after (POST) a half marathon. The maximal voluntary contraction force, rate of force development (RFDpeak), and their ratio (relative RFDpeak) were calculated. At POST, considering the first (out of 15) repetition, the maximal force and RFDpeak decreased (p<0.0001) at the same extent (by 22±6% and 24±22%, respectively), resulting in unchanged relative RFDpeak (p=0.6). Conversely, the decline of RFDpeak throughout the repetitions was more pronounced at POST (p=0.02), thus the decline of relative RFDpeak was more pronounced (p=0.007) at POST (-25±13%) than at PRE (-3±13%). The main finding of this study was that the fatigue induced by a half-marathon caused a more pronounced impairment of rapid compared to maximal force in the subsequent intermittent protocol. Thus, the fatigue-induced impairment in rapid muscle contractions may have a greater effect on repeated, rather than on single, attempts of maximal force production. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. 19 CFR 102.19 - NAFTA preference override.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false NAFTA preference override. 102.19 Section 102.19... TREASURY RULES OF ORIGIN Rules of Origin § 102.19 NAFTA preference override. (a) Except in the case of... single NAFTA country, the country of origin of such good is the last NAFTA country in which that good...

  10. Three-dimensional miscible displacement simulations in homogeneous porous media with gravity override

    Science.gov (United States)

    Riaz, A.; Meiburg, E.

    2003-11-01

    High-accuracy three-dimensional numerical simulations of miscible displacements with gravity override in homogeneous porous media are carried out for the quarter five-spot configuration. Special emphasis is placed on describing the influence of viscous and gravitational effects on the overall displacement dynamics in terms of the vorticity variable. Even for neutrally buoyant displacements, three-dimensional effects are seen to change the character of the flow significantly, in contrast to earlier findings for rectilinear displacements. At least in part this can be attributed to the time dependence of the most dangerous vertical instability mode. Density differences influence the flow primarily by establishing a narrow gravity layer, in which the effective Péclet number is enhanced owing to the higher flow rate. However, buoyancy forces of a certain magnitude can lead to a pinch-off of the gravity layer, thereby slowing it down. Overall, an increase of the gravitational parameter is found to enhance mostly the vertical perturbations, while larger Pe values act towards amplifying horizontal disturbances. The asymptotic rate of growth of the mixing length varies only with Péclet number. For large Péclet numbers, an asymptotic value of 0.7 is observed. A scaling law for the thickness of the gravity layer is obtained as well. In contrast to immiscible flow displacements, it is found to increase with the gravity parameter.

  11. Forced-air warming discontinued: periprosthetic joint infection rates drop

    Directory of Open Access Journals (Sweden)

    Scott D. Augustine

    2017-06-01

    Full Text Available Several studies have shown that the waste heat from forced-air warming (FAW escapes near the floor and warms the contaminated air resident near the floor. The waste heat then forms into convection currents that rise up and contaminate the sterile field above the surgical table. It has been shown that a single airborne bacterium can cause a periprosthetic joint infection (PJI following joint replacement surgery. We retrospectively compared PJI rates during a period of FAW to a period of air-free conductive fabric electric warming (CFW at three hospitals. Surgical and antibiotic protocols were held constant. The pooled multicenter data showed a decreased PJI rate of 78% following the discontinuation of FAW and a switch to air-free CFW (n=2034; P=0.002. The 78% reduction in joint implant infections observed when FAW was discontinued suggests that there is a link between the waste FAW heat and PJIs.

  12. Modulation of post‐movement beta rebound by contraction force and rate of force development

    Science.gov (United States)

    Fry, Adam; Mullinger, Karen J.; O'Neill, George C.; Barratt, Eleanor L.; Morris, Peter G.; Bauer, Markus; Folland, Jonathan P.

    2016-01-01

    Abstract Movement induced modulation of the beta rhythm is one of the most robust neural oscillatory phenomena in the brain. In the preparation and execution phases of movement, a loss in beta amplitude is observed [movement related beta decrease (MRBD)]. This is followed by a rebound above baseline on movement cessation [post movement beta rebound (PMBR)]. These effects have been measured widely, and recent work suggests that they may have significant importance. Specifically, they have potential to form the basis of biomarkers for disease, and have been used in neuroscience applications ranging from brain computer interfaces to markers of neural plasticity. However, despite the robust nature of both MRBD and PMBR, the phenomena themselves are poorly understood. In this study, we characterise MRBD and PMBR during a carefully controlled isometric wrist flexion paradigm, isolating two fundamental movement parameters; force output, and the rate of force development (RFD). Our results show that neither altered force output nor RFD has a significant effect on MRBD. In contrast, PMBR was altered by both parameters. Higher force output results in greater PMBR amplitude, and greater RFD results in a PMBR which is higher in amplitude and shorter in duration. These findings demonstrate that careful control of movement parameters can systematically change PMBR. Further, for temporally protracted movements, the PMBR can be over 7 s in duration. This means accurate control of movement and judicious selection of paradigm parameters are critical in future clinical and basic neuroscientific studies of sensorimotor beta oscillations. Hum Brain Mapp 37:2493–2511, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc PMID:27061243

  13. Modulation of post-movement beta rebound by contraction force and rate of force development.

    Science.gov (United States)

    Fry, Adam; Mullinger, Karen J; O'Neill, George C; Barratt, Eleanor L; Morris, Peter G; Bauer, Markus; Folland, Jonathan P; Brookes, Matthew J

    2016-07-01

    Movement induced modulation of the beta rhythm is one of the most robust neural oscillatory phenomena in the brain. In the preparation and execution phases of movement, a loss in beta amplitude is observed [movement related beta decrease (MRBD)]. This is followed by a rebound above baseline on movement cessation [post movement beta rebound (PMBR)]. These effects have been measured widely, and recent work suggests that they may have significant importance. Specifically, they have potential to form the basis of biomarkers for disease, and have been used in neuroscience applications ranging from brain computer interfaces to markers of neural plasticity. However, despite the robust nature of both MRBD and PMBR, the phenomena themselves are poorly understood. In this study, we characterise MRBD and PMBR during a carefully controlled isometric wrist flexion paradigm, isolating two fundamental movement parameters; force output, and the rate of force development (RFD). Our results show that neither altered force output nor RFD has a significant effect on MRBD. In contrast, PMBR was altered by both parameters. Higher force output results in greater PMBR amplitude, and greater RFD results in a PMBR which is higher in amplitude and shorter in duration. These findings demonstrate that careful control of movement parameters can systematically change PMBR. Further, for temporally protracted movements, the PMBR can be over 7 s in duration. This means accurate control of movement and judicious selection of paradigm parameters are critical in future clinical and basic neuroscientific studies of sensorimotor beta oscillations. Hum Brain Mapp 37:2493-2511, 2016. © 2016 Wiley Periodicals, Inc.

  14. The effect of rate of force development on maximal force production: acute and training-related aspects.

    Science.gov (United States)

    Holtermann, Andreas; Roeleveld, Karin; Vereijken, Beatrix; Ettema, Gertjan

    2007-04-01

    The force generated during a maximal voluntary contraction (MVC) is known to increase by resistance training. Although this increase cannot be solely attributed to changes in the muscle itself, many studies examining muscle activation at peak force failed to detect neural adaptations with resistance training. However, the activation prior to peak force can have an impact on maximal force generation. This study aims at investigating the role of rate of force development (RFD) on maximal force during resistance training. Fourteen subjects carried out 5 days of isometric resistance training with dorsiflexion of the ankle with the instruction to generate maximal force. In a second experiment, 18 subjects performed the same task with the verbal instruction to generate maximal force (instruction I) and to generate force as fast and forcefully as possible (instruction II). The main findings were that RFD increased twice as much as the 16% increase in maximal force with training, with a positive association between RFD and force within the last session of training and between training sessions. Instruction II generated a higher RFD than instruction I, with no difference in maximal force. These findings suggest that the positive association between RFD and maximal force is not causal, but is mediated by a third factor. In the discussion, we argue for the third factor to be physiological changes affecting both aspects of a MVC or different processes affecting RFD and maximal force separately, rather than a voluntary strategic change of both aspects of MVC.

  15. Somatosensory Gating Is Dependent on the Rate of Force Recruitment in the Human Orofacial System

    Science.gov (United States)

    Andreatta, Richard D.; Barlow, Steven M.

    2009-01-01

    Purpose: Functional orofacial behaviors vary in their force endpoint and rate of recruitment. This study assessed the gating of orofacial cutaneous somatosensation during different cyclic lip force recruitment rates. Understanding how differences in the rate of force recruitment influences trigeminal system function is an important step toward…

  16. Somatosensory Gating Is Dependent on the Rate of Force Recruitment in the Human Orofacial System

    Science.gov (United States)

    Andreatta, Richard D.; Barlow, Steven M.

    2009-01-01

    Purpose: Functional orofacial behaviors vary in their force endpoint and rate of recruitment. This study assessed the gating of orofacial cutaneous somatosensation during different cyclic lip force recruitment rates. Understanding how differences in the rate of force recruitment influences trigeminal system function is an important step toward…

  17. Climate forcing growth rates: doubling down on our Faustian bargain

    Science.gov (United States)

    Hansen, James; Kharecha, Pushker; Sato, Makiko

    2013-03-01

    Rahmstorf et al 's (2012) conclusion that observed climate change is comparable to projections, and in some cases exceeds projections, allows further inferences if we can quantify changing climate forcings and compare those with projections. The largest climate forcing is caused by well-mixed long-lived greenhouse gases. Here we illustrate trends of these gases and their climate forcings, and we discuss implications. We focus on quantities that are accurately measured, and we include comparison with fixed scenarios, which helps reduce common misimpressions about how climate forcings are changing. Annual fossil fuel CO2 emissions have shot up in the past decade at about 3% yr-1, double the rate of the prior three decades (figure 1). The growth rate falls above the range of the IPCC (2001) 'Marker' scenarios, although emissions are still within the entire range considered by the IPCC SRES (2000). The surge in emissions is due to increased coal use (blue curve in figure 1), which now accounts for more than 40% of fossil fuel CO2 emissions. Figure 1. Figure 1. CO2 annual emissions from fossil fuel use and cement manufacture, an update of figure 16 of Hansen (2003) using data of British Petroleum (BP 2012) concatenated with data of Boden et al (2012). The resulting annual increase of atmospheric CO2 (12-month running mean) has grown from less than 1 ppm yr-1 in the early 1960s to an average ~2 ppm yr-1 in the past decade (figure 2). Although CO2 measurements were not made at sufficient locations prior to the early 1980s to calculate the global mean change, the close match of global and Mauna Loa data for later years suggests that Mauna Loa data provide a good approximation of global change (figure 2), thus allowing a useful estimate of annual global change beginning with the initiation of Mauna Loa measurements in 1958 by Keeling et al (1973). Figure 2. Figure 2. Annual increase of CO2 based on data from the NOAA Earth System Research Laboratory (ESRL 2012). CO2 change

  18. Rate of force development as a measure of muscle damage.

    Science.gov (United States)

    Peñailillo, L; Blazevich, A; Numazawa, H; Nosaka, K

    2015-06-01

    This study tested the hypothesis that rate of force development (RFD) would be a more sensitive indirect marker of muscle damage than maximum voluntary isometric contraction (MVC) peak torque. Ten men performed one concentric cycling and two eccentric cycling (ECC1, ECC2) bouts for 30 min at 60% of maximal concentric power output with 2 weeks between bouts. MVC peak torque, RFD, and vastus lateralis electromyogram amplitude and mean frequency were measured during a knee extensor MVC before, immediately after and 1-2 days after each bout. The magnitude of decrease in MVC peak torque after exercise was greater (P < 0.05) for ECC1 (11-25%) than concentric cycling (2-12%) and ECC2 (0-16%). Peak RFD and RFD from 0-30 ms, 0-50 ms, 0-100 ms, to 0-200 ms decreased (P < 0.05) immediately after all cycling bouts without significant differences between bouts, but RFD at 100-200 ms interval (RFD(100-200)) decreased (P < 0.05) at all time points after ECC1 (24-32%) and immediately after ECC2 (23%), but did not change after CONC. The magnitude of decrease in RFD(100-200) was 7-19% greater than that of MVC peak torque after ECC1 (P < 0.05). It is concluded that RFD(100-200) is a more specific and sensitive indirect marker of eccentric exercise-induced muscle damage than MVC peak torque.

  19. Confidence in Forced-Choice Recognition: What Underlies the Ratings?

    Science.gov (United States)

    Zawadzka, Katarzyna; Higham, Philip A.; Hanczakowski, Maciej

    2017-01-01

    Two-alternative forced-choice recognition tests are commonly used to assess recognition accuracy that is uncontaminated by changes in bias. In such tests, participants are asked to endorse the studied item out of 2 presented alternatives. Participants may be further asked to provide confidence judgments for their recognition decisions. It is often…

  20. Confidence in Forced-Choice Recognition: What Underlies the Ratings?

    Science.gov (United States)

    Zawadzka, Katarzyna; Higham, Philip A; Hanczakowski, Maciej

    2016-09-29

    Two-alternative forced-choice recognition tests are commonly used to assess recognition accuracy that is uncontaminated by changes in bias. In such tests, participants are asked to endorse the studied item out of 2 presented alternatives. Participants may be further asked to provide confidence judgments for their recognition decisions. It is often assumed that both recognition decisions and confidence judgments in 2-alternative forced-choice recognition tests depend on participants' assessments of a difference in strength of memory evidence supporting the 2 alternatives-the relative account. In the present study we focus on the basis of confidence judgments and we assess the relative account of confidence against the absolute account of confidence, by which in assigning confidence participants consider only strength of memory evidence supporting the chosen alternative. The results of the study show that confidence in 2-alternative forced-choice recognition decisions is higher when memory evidence is stronger for the chosen alternative and also when memory evidence is stronger for the unchosen alternative. These patterns of results are consistent with the absolute account of confidence in 2-alternative forced-choice recognition but they are inconsistent with the relative account. (PsycINFO Database Record

  1. Specific cerebellar regions are related to force amplitude and rate of force development

    OpenAIRE

    Spraker, M B.; Corcos, D.M.; Kurani, A.S.; Prodoehl, J; Swinnen, S.P.; Vaillancourt, D E

    2011-01-01

    The human cerebellum has been implicated in the control of a wide variety of motor control parameters, such as force amplitude, movement extent, and movement velocity. These parameters often covary in both movement and isometric force production tasks, so it is difficult to resolve whether specific regions of the cerebellum relate to specific parameters. In order to address this issue, the current study used two experiments and SUIT normalization to determine whether BOLD activation in the ce...

  2. Forecasting Foreign Currency Exchange Rates for Air Force Budgeting

    Science.gov (United States)

    2015-03-26

    Corte et al., 2008). Artificial neural networks (self- learning algorithms trained on historical data) show robust exchange rate predictions in midst...original study. Auction theory provides another method of forecasting exchange rates. The international exchange market for currencies acts as an... auction , and the future options on currencies may give insight into forecasting the exchange rate. If there are many traders for the currency, the

  3. Program participation, labor force dynamics, and accepted wage rates

    DEFF Research Database (Denmark)

    Munch, Jakob Roland; Skipper, Lars

    2008-01-01

    transition rate from unemployment to employment upon completion. Most programs, therefore, increase the expected duration of unemployment spells. However, we find that the training undertaken while unemployed successfully increases the expected duration of subsequent spells of employment for many...... subpopulations. These longer spells of employment come at a cost of lower accepted hourly wage rates...

  4. The differential effect of metabolic alkalosis on maximum force and rate of force development during repeated, high-intensity cycling.

    Science.gov (United States)

    Siegler, Jason C; Marshall, Paul W M; Raftry, Sean; Brooks, Cristy; Dowswell, Ben; Romero, Rick; Green, Simon

    2013-12-01

    The purpose of this investigation was to assess the influence of sodium bicarbonate supplementation on maximal force production, rate of force development (RFD), and muscle recruitment during repeated bouts of high-intensity cycling. Ten male and female (n = 10) subjects completed two fixed-cadence, high-intensity cycling trials. Each trial consisted of a series of 30-s efforts at 120% peak power output (maximum graded test) that were interspersed with 30-s recovery periods until task failure. Prior to each trial, subjects consumed 0.3 g/kg sodium bicarbonate (ALK) or placebo (PLA). Maximal voluntary contractions were performed immediately after each 30-s effort. Maximal force (F max) was calculated as the greatest force recorded over a 25-ms period throughout the entire contraction duration while maximal RFD (RFD max) was calculated as the greatest 10-ms average slope throughout that same contraction. F max declined similarly in both the ALK and PLA conditions, with baseline values (ALK: 1,226 ± 393 N; PLA: 1,222 ± 369 N) declining nearly 295 ± 54 N [95% confidence interval (CI) = 84-508 N; P force vs. maximum rate of force development during a whole body fatiguing task.

  5. Program participation, labor force dynamics, and accepted wage rates

    DEFF Research Database (Denmark)

    Munch, Jakob Roland; Skipper, Lars

    2008-01-01

    We apply a recently suggested econometric approach to measure the effects of active labor market programs on employment, unemployment, and wage histories among participants. We find that participation in most of these training programs produces an initial locking-in effect and for some even a lower...... subpopulations. These longer spells of employment come at a cost of lower accepted hourly wage rates...

  6. Rates of change in natural and anthropogenic radiative forcing over the past 20,000 years.

    Science.gov (United States)

    Joos, Fortunat; Spahni, Renato

    2008-02-05

    The rate of change of climate codetermines the global warming impacts on natural and socioeconomic systems and their capabilities to adapt. Establishing past rates of climate change from temperature proxy data remains difficult given their limited spatiotemporal resolution. In contrast, past greenhouse gas radiative forcing, causing climate to change, is well known from ice cores. We compare rates of change of anthropogenic forcing with rates of natural greenhouse gas forcing since the Last Glacial Maximum and of solar and volcanic forcing of the last millennium. The smoothing of atmospheric variations by the enclosure process of air into ice is computed with a firn diffusion and enclosure model. The 20th century increase in CO(2) and its radiative forcing occurred more than an order of magnitude faster than any sustained change during the past 22,000 years. The average rate of increase in the radiative forcing not just from CO(2) but from the combination of CO(2), CH(4), and N(2)O is larger during the Industrial Era than during any comparable period of at least the past 16,000 years. In addition, the decadal-to-century scale rate of change in anthropogenic forcing is unusually high in the context of the natural forcing variations (solar and volcanoes) of the past millennium. Our analysis implies that global climate change, which is anthropogenic in origin, is progressing at a speed that is unprecedented at least during the last 22,000 years.

  7. Refinement of the Air Force Systems Command Production Rate Model

    Science.gov (United States)

    1989-09-01

    the recommended modified formulations. The relationship between production rate and production ratio has a definite influence on the model’s ability to...1984 7 36 21.954 370.00 1985 8 48 21.017 412.00 A- 3 Table A.2.8 F-15E Cost/Quantity Data Fiscal Year Lot Quntit Recurring Unit Cost LPP 1986 1 60

  8. Rate of force generation in muscle: correlation with actomyosin ATPase activity in solution.

    OpenAIRE

    Brenner, B; Eisenberg, E

    1986-01-01

    Crossbridge models of muscle contraction based on biochemical studies predict that there may be a relationship between the rate-limiting step in the actomyosin ATPase cycle in vitro and the rate of force development in vivo. In the present study, we measured the rate of force redevelopment in skinned rabbit muscle fibers following unloaded isotonic shortening and a rapid restretch. For comparison, ATPase activity was measured under identical conditions, using myosin subfragment-1 chemically c...

  9. Paddling Force Profiles at Different Stroke Rates in Elite Sprint Kayaking.

    Science.gov (United States)

    Gomes, Beatriz B; Ramos, Nuno V; Conceição F, A V; Sanders, Ross H; Vaz, Mário A; Vilas-Boas, João Paulo

    2015-08-01

    In sprint kayaking the role that paddling technique plays in optimizing paddle forces and resultant kayak kinematics is still unclear. The aim of this study was to analyze the magnitude and shape of the paddle force-time curve at different stroke rates, and their implications for kayak performance. Ten elite kayak paddlers (5 males and 5 females) were analyzed while performing 2000-m on-water trials, at 4 different paces (60, 80, and 100 strokes per minute, and race pace). The paddle and kayak were instrumented with strain gauges and accelerometers, respectively. For both sexes, the force-time curves were characterized at training pace by having a bell shape and at race pace by a first small peak, followed by a small decrease in force and then followed by a main plateau. The force profile, represented by the mean force/peak force ratio, became more rectangular with increasing stroke rate (F[3,40] = 7.87, P kayak paddlers should seek a stronger water phase with a rapid increase in force immediately after blade entry, and a quick exit before the force dropping far below the maximum force. This pattern should be sought when training at race pace and in competition.

  10. Is the Labour Force Participation Rate Non-Stationary in Romania?

    Directory of Open Access Journals (Sweden)

    Tiwari Aviral Kumar

    2015-01-01

    Full Text Available The purpose of this paper is to test hysteresis of the Romanian labour force participation rate, by using time series data, with quarterly frequency, covering the period 1999Q1-2013Q4. The main results reveal that the Romanian labour force participation rate is a nonlinear process and has a partial unit root (i.e. it is stationary in the first regime and non-stationary in the second one, the main breaking point being registered around year 2005. In this context, the value of using unemployment rate as an indicator for capturing joblessness in this country is debatable. Starting from 2005, the participation rate has not followed long-term changes in unemployment rate, the disturbances having permanent effects on labour force participation rate.

  11. Stereotypes override grammar: Social knowledge in sentence comprehension.

    Science.gov (United States)

    Molinaro, Nicola; Su, Jui-Ju; Carreiras, Manuel

    2016-01-01

    Many studies have provided evidence for the automaticity and immediacy with which stereotypical knowledge affects our behavior. However, less is known about how such social knowledge interacts with linguistic cues during comprehension. In this ERP sentence processing study we took advantage of the rich grammatical gender morphology of Spanish to explore the processing of role nouns in which stereotype and grammatical cues were simultaneously manipulated, in a factorial design. We show that stereotypical knowledge overrides syntactic cues, highlighting the immediacy with which stereotype knowledge is activated during language comprehension and supporting proposals claiming that social knowledge impacts on language processing differently from other forms of semantics.

  12. Microfluidic multifunctional probe array dielectrophoretic force spectroscopy with wide loading rates.

    Science.gov (United States)

    Park, In Soo; Eom, Kilho; Son, Jongsang; Chang, Woo-Jin; Park, Kidong; Kwon, Taeyun; Yoon, Dae Sung; Bashir, Rashid; Lee, Sang Woo

    2012-10-23

    The simultaneous investigation of a large number of events with different types of intermolecular interactions, from nonequilibrium high-force pulling assays to quasi-equilibrium unbinding events in the same environment, can be very important for fully understanding intermolecular bond-rupture mechanisms. Here, we describe a novel dielectrophoretic force spectroscopy technique that utilizes microsized beads as multifunctional probes for parallel measurement of intermolecular forces with an extremely wide range of force rate (10(-4) to 10(4) pN/s) inside a microfluidic device. In our experiments, various forces, which broadly form the basis of all molecular interactions, were measured across a range of force loading rates by multifunctional probes of various diameters with a throughput of over 600 events per mm(2), simultaneously and in the same environment. Furthermore, the individual bond-rupture forces, the parameters for the characterization of entire energy landscapes, and the effective stiffness of the force spectroscopy were determined on the basis of the measured results. This method of determining intermolecular forces could be very useful for the precise and simultaneous examination of various molecular interactions, as it can be easily and cost-effectively implemented within a microfluidic device for a range of applications including immunoassays, molecular mechanics, chemical and biological screening, and mechanobiology.

  13. The effects of stretching exercise for upper trapezius on the asymmetric rate of bite force.

    Science.gov (United States)

    Lee, Bomjin; Lee, Joongsook; Yang, Jeongok; Heo, Kwangjin; Hwang, Hojin; Kim, Boyoung; Han, Dongwook

    2015-07-01

    [Purpose] The purpose of this study was to observe the effects of stretching the upper trapezius muscle on the asymmetric rate of bite force. [Subjects] Forty-seven female university students who had all their original teeth, had no disorders in the temporomandibular joints, and had never worn braces; participated in this study. [Methods] An occlusometer was used to measure biting forces. Subsequently, stretching exercises of the upper trapezius were performed. The subjects were divided into 3 groups at the start of the testing: the asymmetric rate of the first group was less than 10%; the asymmetric rate of the second group was between 10% and 20%; and the asymmetric rate of the third group was more than 20%. The stretching exercises were done on the dominant side of the upper trapezius. [Results] After the stretching exercises of the upper trapezius, the results showed that for the first group, whose asymmetric rate of biting force was less than 10%, there was a significant increase in asymmetric rate (from 5.1% to 10.3%). For the second group, whose asymmetric rate of biting force was measured to be between 10% and 20%, the asymmetric rate decreased from 14.7% to 14.3%, but the change was not statistically significant. For the third group, whose asymmetric rate of biting force was more than 20%, there was a significant decrease in asymmetric rate (from 27.8% to 12.6%). [Conclusion] We concluded that stretching exercises of the upper trapezius muscle had a direct effect on the asymmetric rate of biting force.

  14. Within- and between-session reliability of power, force, and rate of force development during the power clean.

    Science.gov (United States)

    Comfort, Paul

    2013-05-01

    Although there has been extensive research regarding the power clean, its application to sports performance, and use as a measure of assessing changes in performance, no research has determined the reliability assessing the kinetics of the power clean across testing session. The aim of this study was to determine the within- and between-session reliability of kinetic variables during the power clean. Twelve professional rugby league players (age 24.5 ± 2.1 years; height 182.86 ± 6.97 cm; body mass 92.85 ± 5.67 kg; 1 repetition maximum [1RM] power clean 102.50 ± 10.35 kg) performed 3 sets of 3 repetitions of power cleans at 70% of their 1RM, while standing on a force plate, to determine within-session reliability and repeated on 3 separate occasions to determine reliability between sessions. Intraclass correlation coefficients revealed a high reliability within- (r ≥ 0.969) and between-sessions (r ≥ 0.988). Repeated-measures analysis of variance showed no significant difference (p > 0.05) in peak vertical ground reaction force, rate of force development, and peak power between sessions, with small standard error of the measurements and smallest detectable differences for each kinetic variable (3.13 and 8.68 N; 84.39 and 233.93 N·s; 24.54 and 68.01 W, respectively). Therefore, to identify a meaningful change in performance, the strength and conditioning coach should look for a change in peak force ≥8.68 N, rate of force development ≥24.54 N·s, and a change in peak power ≥68.01 W to signify an adaptive response to training, which is greater than the variance between sessions, in trained athletes proficient at performing the power clean.

  15. Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

    Directory of Open Access Journals (Sweden)

    Martínez-Valencia María Asunción

    2015-06-01

    Full Text Available Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak, a peak rate of force development (RFDpeak and time to RFD (TRFD in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001 in sprint times (20 and 30 m sprint for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s−1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s−1, p ≤ 0.01. Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration.

  16. Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

    Science.gov (United States)

    Martínez-Valencia, María Asunción; Romero-Arenas, Salvador; Elvira, José L.L.; González-Ravé, José María; Navarro-Valdivielso, Fernando; Alcaraz, Pedro E.

    2015-01-01

    Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s−1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s−1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration. PMID:26240657

  17. Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase.

    Science.gov (United States)

    Martínez-Valencia, María Asunción; Romero-Arenas, Salvador; Elvira, José L L; González-Ravé, José María; Navarro-Valdivielso, Fernando; Alcaraz, Pedro E

    2015-06-27

    Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s-1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s-1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration.

  18. Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis

    Science.gov (United States)

    2015-03-26

    required and expected . Additionally, the experience they gather throughout their careers is invaluable to the success of the Air Force and cannot be...The service commitments and career paths tend to be relatively equal within this group, so the attrition behavior was expected to be approximately the... females , given that they are in the same yeargroup, career field, etc. Although the actual reason cannot be determined based on this data, one can attribute

  19. Rate enhancement in microfabricated chemical reactors under fast forced temperature oscillations

    DEFF Research Database (Denmark)

    Hansen, Heine Anton; Olsen, Jakob L.; Jensen, Søren;

    2006-01-01

    Oxidation of CO under fast forced temperature oscillations shows increased reaction rate compared to steady state. A maximum increase of 40% is observed relative to steady state. The reaction rate is investigated for varying mean temperature, amplitude and frequency. As function of mean temperature...

  20. Effects of series elastic compliance on muscle force summation and the rate of force rise.

    Science.gov (United States)

    Mayfield, Dean L; Cresswell, Andrew G; Lichtwark, Glen A

    2016-10-15

    Compliant tendons permit mechanically unfavourable fascicle dynamics during fixed-end contractions. The purpose of this study was to reduce the effective compliance of tendon and investigate how small reductions in active shortening affect twitch kinetics and contractile performance in response to a second stimulus. The series elastic element (SEE) of the human triceps surae (N=15) was effectively stiffened by applying a 55 ms rotation to the ankle, through a range of 5 deg, at the onset of twitch and doublet [interstimulus interval (ISI) of 80 ms] stimulation. Ultrasonography was employed to quantify lateral gastrocnemius and soleus fascicle lengths. Rotation increased twitch torque (40-75%), rate of torque development (RTD; 124-154%) and torque-time integral (TTI; 70-110%) relative to constant-length contractions at the initial and final joint positions, yet caused only modest reductions in shortening amplitude and velocity. The torque contribution of the second pulse increased when stimulation was preceded by rotation, a finding unable to be explained on the basis of fascicle length or SEE stiffness during contraction post-rotation. A further increase in torque contribution was not demonstrated, nor was an increase in doublet TTI, when the second pulse was delivered during rotation and shortly after the initial pulse (ISI of 10 ms). The depressant effect of active shortening on subsequent torque generation suggests that compliant tendons, by affording large length changes, may limit torque summation. Our findings indicate that changes in tendon compliance shown to occur in response to resistance training or unloading are likely sufficient to considerably alter contractile performance, particularly maximal RTD.

  1. Along-strike variation in subducting plate velocity induced by along-strike variation in overriding plate structure: Insights from 3D numerical models

    Science.gov (United States)

    Rodríguez-González, Juan; Billen, Magali I.; Negredo, Ana M.; Montesi, Laurent G. J.

    2016-10-01

    Subduction dynamics can be understood as the result of the balance between driving and resisting forces. Previous work has traditionally regarded gravitational slab pull and viscous mantle drag as the main driving and resistive forces for plate motion respectively. However, this paradigm fails to explain many of the observations in subduction zones. For example, subducting plate velocity varies significantly along-strike in many subduction zones and this variation is not correlated to the age of subducting lithosphere. Here we present three-dimensional and time-dependent numerical models of subduction. We show that along-strike variations of the overriding plate thermal structure can lead to along-strike variations in subducting plate velocity. In turn, velocity variations lead to significant migration of the Euler pole over time. Our results show that the subducting plate is slower beneath the colder portion of the overriding plate due to two related mechanisms. First, the mantle wedge beneath the colder portion of the overriding plate is more viscous, which increases mantle drag. Second, where the mantle wedge is more viscous, hydrodynamic suction increases, leading to a lower slab dip. Both factors contribute to decreasing subducting plate velocity in the region; therefore, if the overriding plate is not uniform, the resulting velocity varies significantly along-strike, which causes the Euler pole to migrate closer to the subducting plate. We present a new mechanism to explain observations of subducting plate velocity in the Cocos and Nazca plates. These results shed new light on the balance of forces that control subduction dynamics and prove that future studies should take into consideration the three-dimensional structure of the overriding plate.

  2. Firing rate modulation of human motor units in different muscles during isometric contraction with various forces.

    Science.gov (United States)

    Seki, K; Narusawa, M

    1996-05-06

    To examine the factors affecting the control of human motor units, rate coding strategies of the motor units were investigated in upper limb and intrinsic hand muscles during voluntary isometric contraction of steady force levels up to 80% of maximal voluntary contraction. Numerous spike trains from single motor units were recorded from the m. first dorsal interosseous (FDI) and the m. biceps brachii (BB) of eight human subjects by means of tungsten micro-electrodes, and the mean firing rate (MFR) was calculated for each subject and inter-individual comparisons made. The MFRs of the FDI were larger than that of the BB at the higher force level, and substantial differences were not found between these muscles at the lower force level. The slope of the linear regression line of MFRs vs. exerted forces for the FDI was more than twice that for the BB. Therefore, isometric force control of the FDI depends more on the rate coding strategy. The difference in rate coding between the FDI and BB motor units may be determined by factors other than muscle fiber composition, because both muscles are known to possess a similar composition of fiber types. Possible mechanisms underlying these characteristics of rate coding strategy are considered in this report.

  3. Increased rate of force development of elbow flexors by antagonist conditioning contraction.

    Science.gov (United States)

    Kamimura, Takashi; Yoshioka, Koichi; Ito, Susumu; Kusakabe, Tatsumi

    2009-08-01

    The effects of isometric antagonist conditioning contraction (ACC) at various durations and intensities on the contractile force, electromyographic (EMG) amplitude, and their rates of rise of elbow flexor muscles were examined in healthy participants. In particular, we focused on the change in the maximum rate of initial force development of agonists (dFagonist/dt(max)), which was evaluated by subtracting antagonist force decaying from apparent initial force development. While the ACC caused no statistically significant effect on the average force during elbow flexion, dFagonist/dt(max) was significantly increased by the ACC of short durations (1-2s) and large intensities. Similarly, the ACC did not affect the root mean square EMG amplitude of biceps brachii during elbow flexion, but significantly increased the maximum rate of rise of the absolute EMG amplitude (dE/dt(max)). These results suggested that facilitating effects of the ACC could be observed in the initial phase of agonist action in healthy participants, and ACC of shorter durations might be more effective. The increased dE/dt(max) suggested that increased neural activities might contribute to the antagonist conditioned facilitation of force development.

  4. Override the controversy: Analytic thinking predicts endorsement of evolution.

    Science.gov (United States)

    Gervais, Will M

    2015-09-01

    Despite overwhelming scientific consensus, popular opinions regarding evolution are starkly divided. In the USA, for example, nearly one in three adults espouse a literal and recent divine creation account of human origins. Plausibly, resistance to scientific conclusions regarding the origins of species-like much resistance to other scientific conclusions (Bloom & Weisberg, 2007)-gains support from reliably developing intuitions. Intuitions about essentialism, teleology, agency, and order may combine to make creationism potentially more cognitively attractive than evolutionary concepts. However, dual process approaches to cognition recognize that people can often analytically override their intuitions. Two large studies (total N=1324) found consistent evidence that a tendency to engage analytic thinking predicted endorsement of evolution, even controlling for relevant demographic, attitudinal, and religious variables. Meanwhile, exposure to religion predicted reduced endorsement of evolution. Cognitive style is one factor among many affecting opinions on the origin of species. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Comparisons of peak ground reaction force and rate of force development during variations of the power clean.

    Science.gov (United States)

    Comfort, Paul; Allen, Mark; Graham-Smith, Phillip

    2011-05-01

    The aim of this investigation was to determine the differences in vertical ground reaction forces and rate of force development (RFD) during variations of the power clean. Elite rugby league players (n = 11; age 21 ± 1.63 years; height 181.56 ± 2.61 cm; body mass 93.65 ± 6.84 kg) performed 1 set of 3 repetitions of the power clean, hang-power clean, midthigh power clean, or midthigh clean pull, using 60% of 1-repetition maximum power clean, in a randomized order, while standing on a force platform. Differences in peak vertical ground reaction forces (F(z)) and instantaneous RFD between lifts were analyzed via 1-way analysis of variance and Bonferroni post hoc analysis. Statistical analysis revealed a significantly (p < 0.001) greater peak F(z) during the midthigh power clean (2,801.7 ± 195.4 N) and the midthigh clean pull (2,880.2 ± 236.2 N) compared to both the power clean (2,306.24 ± 240.47 N) and the hang-power clean (2,442.9 ± 293.2 N). The midthigh power clean (14,655.8 ± 4,535.1 N·s⁻¹) and the midthigh clean pull (15,320.6 ± 3,533.3 N·s⁻¹) also demonstrated significantly (p < 0.001) greater instantaneous RFD when compared to both the power clean (8,839.7 ± 2,940.4 N·s⁻¹) and the hang-power clean (9,768.9 ± 4,012.4 N·s⁻¹). From the findings of this study, when training to maximize peak F(z) and RFD the midthigh power clean and midthigh clean pull appear to be the most advantageous variations of the power clean to perform.

  6. Extraction of time and frequency features from grip force rates during dexterous manipulation.

    Science.gov (United States)

    Mojtahedi, Keivan; Fu, Qiushi; Santello, Marco

    2015-05-01

    The time course of grip force from object contact to onset of manipulation has been extensively studied to gain insight into the underlying control mechanisms. Of particular interest to the motor neuroscience and clinical communities is the phenomenon of bell-shaped grip force rate (GFR) that has been interpreted as indicative of feedforward force control. However, this feature has not been assessed quantitatively. Furthermore, the time course of grip force may contain additional features that could provide insight into sensorimotor control processes. In this study, we addressed these questions by validating and applying two computational approaches to extract features from GFR in humans: 1) fitting a Gaussian function to GFR and quantifying the goodness of the fit [root-mean-square error, (RMSE)]; and 2) continuous wavelet transform (CWT), where we assessed the correlation of the GFR signal with a Mexican Hat function. Experiment 1 consisted of a classic pseudorandomized presentation of object mass (light or heavy), where grip forces developed to lift a mass heavier than expected are known to exhibit corrective responses. For Experiment 2, we applied our two techniques to analyze grip force exerted for manipulating an inverted T-shaped object whose center of mass was changed across blocks of consecutive trials. For both experiments, subjects were asked to grasp the object at either predetermined or self-selected grasp locations ("constrained" and "unconstrained" task, respectively). Experiment 1 successfully validated the use of RMSE and CWT as they correctly distinguished trials with versus without force corrective responses. RMSE and CWT also revealed that grip force is characterized by more feedback-driven corrections when grasping at self-selected contact points. Future work will examine the application of our analytical approaches to a broader range of tasks, e.g., assessment of recovery of sensorimotor function following clinical intervention, interlimb

  7. Ground Forces Battle Casualty Rate Patterns: Current Rate Projections Compared to the Empirical Evidence.

    Science.gov (United States)

    1990-05-01

    in terms of rate severity levels. The first kind of disrupted front may be illustrated by the German Kharkov and Donbas defensives in early 1943...kind of disrupted front is an exploitation phase which does not witness serious encirclement. At Donbas , two German divisions were briefly...Sandomierz [2nd 10 days] Kharkov Donbas 10 10 10 All < 9-14 DF-1 DF-1 DF-1 Ardennes ("Bulge") [1st 10 days] 10 CF (Def) Central Europe [November

  8. Biomechanics of ant adhesive pads: frictional forces are rate- and temperature-dependent.

    Science.gov (United States)

    Federle, Walter; Baumgartner, Werner; Hölldobler, Bert

    2004-01-01

    Tarsal adhesive pads enable insects to hold on to smooth plant surfaces. Using a centrifuge technique, we tested whether a "wet adhesion" model of a thin film of liquid secreted between the pad and the surface can explain adhesive and frictional forces in Asian Weaver ants (Oecophylla smaragdina). When forces are acting parallel to the surface, pads in contact with the surface can slide smoothly. Force per unit pad contact area was strongly dependent on sliding velocity and temperature. Seemingly consistent with the effect of a thin liquid film in the contact zone, (1) frictional force linearly increased with sliding velocity, (2) the increment was greater at lower temperatures and (3) no temperature dependence was detected for low-rate perpendicular detachment forces. However, we observed a strong, temperature-independent static friction that was inconsistent with a fully lubricated contact. Static friction was too large to be explained by the contribution of other (sclerotized) body parts. Moreover, the rate-specific increase of shear stress strongly exceeded predictions derived from estimates of the adhesive liquid film's thickness and viscosity. Both lines of evidence indicate that the adhesive secretion alone is insufficient to explain the observed forces and that direct interaction of the soft pad cuticle with the surface ("rubber friction") is involved.

  9. Force

    CERN Document Server

    Graybill, George

    2007-01-01

    Forces are at work all around us. Discover what a force is, and different kinds of forces that work on contact and at a distance. We use simple language and vocabulary to make this invisible world easy for students to ""see"" and understand. Examine how forces ""add up"" to create the total force on an object, and reinforce concepts and extend learning with sample problems.

  10. Inferring kinetic pathways, rates, and force dependence from nonprocessive optical tweezers experiments: a maximum likelihood approach

    Science.gov (United States)

    Kalafut, Bennett; Visscher, Koen

    2008-10-01

    Optical tweezers experiments allow us to probe the role of force and mechanical work in a variety of biochemical processes. However, observable states do not usually correspond in a one-to-one fashion with the internal state of an enzyme or enzyme-substrate complex. Different kinetic pathways yield different distributions for the dwells in the observable states. Furthermore, the dwell-time distribution will be dependent upon force, and upon where in the biochemical pathway force acts. I will present a maximum-likelihood method for identifying rate constants and the locations of force-dependent transitions in transcription initiation by T7 RNA Polymerase. This method is generalizable to systems with more complicated kinetic pathways in which there are two observable states (e.g. bound and unbound) and an irreversible final transition.

  11. Early and late rate of force development: differential adaptive responses to resistance training?

    DEFF Research Database (Denmark)

    Andersen, L L; Andersen, Jesper Løvind; Zebis, M K

    2010-01-01

    The objective of this study is to investigate the potentially opposing influence of qualitative and quantitative muscular adaptations in response to high-intensity resistance training on contractile rate of force development (RFD) in the early (200 ms) of rising muscle force. Fifteen healthy young...... the vastus lateralis. The main findings were that RFD in the late phase of rising muscle force increased in response to resistance training whereas early RFD remained unchanged and early relative RFD (i.e., RFD/MVC) decreased. Quantitatively, muscle fiber cross-sectional area and MVC increased whereas......-intensity resistance training due to differential influences of qualitative and quantitative muscular adaptations on early and later phases of rising muscle force....

  12. Effect of Strength Training on Rate of Force Development in Older Women

    Science.gov (United States)

    Gurjao, Andre Luiz Demantova; Gobbi, Lilian Teresa Bucken; Carneiro, Nelson Hilario; Goncalves, Raquel; Ferreira de Moura, Rodrigo; Cyrino, Edilson Serpeloni; Altimari, Leandro Ricardo; Gobbi, Sebastiao

    2012-01-01

    We analyzed the effect of an 8-week strength training (ST) program on the rate of force development (RFD) and electromyographic activity (EMG) in older women. Seventeen women (M age = 63.4 years, SD = 4.9) without previous ST experience were randomly assigned to either a control (n = 7) or training (n = 10) group. A leg-press isometric test was…

  13. Effects of fast-velocity eccentric resistance training on early and late rate of force development

    DEFF Research Database (Denmark)

    Oliveira, Anderson S.C.; Corvino, Rogério Bulhões; Caputo, Fabrizio

    2016-01-01

    This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (100 ms) of rising torque. Twenty healthy men were...

  14. An attempt to bridge muscle architecture dynamics and its instantaneous rate of force development using ultrasonography.

    Science.gov (United States)

    Li, Jizhou; Zhou, Yongjin; Zheng, Yong-Ping; Li, Guanglin

    2015-08-01

    Muscle force output is an essential index in rehabilitation assessment or physical exams, and could provide considerable insights for various applications such as load monitoring and muscle assessment in sports science or rehabilitation therapy. Besides direct measurement of force output using a dynamometer, electromyography has earlier been used in several studies to quantify muscle force as an indirect means. However, its spatial resolution is easily compromised as a summation of the action potentials from neighboring motor units of electrode site. To explore an alternative method to indirectly estimate the muscle force output, and with better muscle specificity, we started with an investigation on the relationship between architecture dynamics and force output of triceps surae. The muscular architecture dynamics is captured in ultrasonography sequences and estimated using a previously reported motion estimation method. Then an indicator named as the dorsoventrally averaged motion profile (DAMP) is employed. The performance of force output is represented by an instantaneous version of the rate of force development (RFD), namely I-RFD. From experimental results on ten normal subjects, there were significant correlations between the I-RFD and DAMP for triceps surae, both normalized between 0 and 1, with the sum of squares error at 0.0516±0.0224, R-square at 0.7929±0.0931 and root mean squared error at 0.0159±0.0033. The statistical significance results were less than 0.01. The present study suggested that muscle architecture dynamics extracted from ultrasonography during contraction is well correlated to the I-RFD and it can be a promising option for indirect estimation of muscle force output.

  15. Influence of forced respiration on nonlinear dynamics in heart rate variability

    DEFF Research Database (Denmark)

    Kanters, J K; Højgaard, M V; Agner, E;

    1997-01-01

    of this study was to test whether the known nonlinear input from spontaneous respiration is a source for the nonlinearities in heart rate variability. Twelve healthy subjects were examined in supine position with 3-h electrocardiogram recordings during both spontaneous and forced respiration in accordance...... expressed as the nonlinear prediction error did not differ between spontaneous respiration, 32.3 +/- 3.4 ms, and forced respiration, 31.9 +/- 5.7. It is concluded that the origin of the nonlinear dynamics in heart rate variability is not a nonlinear input from the respiration into the cardiovascular...... oscillator. Additional studies are needed to elucidate the mechanisms behind the nonlinear dynamics in heart rate variability....

  16. Optimal control of an influenza model with seasonal forcing and age-dependent transmission rates.

    Science.gov (United States)

    Lee, Jeehyun; Kim, Jungeun; Kwon, Hee-Dae

    2013-01-21

    This study considers an optimal intervention strategy for influenza outbreaks. Variations in the SEIAR model are considered to include seasonal forcing and age structure, and control strategies include vaccination, antiviral treatment, and social distancing such as school closures. We formulate an optimal control problem by minimizing the incidence of influenza outbreaks while considering intervention costs. We examine the effects of delays in vaccine production, seasonal forcing, and age-dependent transmission rates on the optimal control and suggest some optimal strategies through numerical simulations.

  17. CONVERGENCE RATES FOR THE COMPRESSIBLE NAVIER-STOKES EQUATIONS WITH GENERAL FORCES

    Institute of Scientific and Technical Information of China (English)

    Qian Jianzhen; Yin Hui

    2009-01-01

    For the viscous and heat-conductive fluids governed by the compressible NavierStokes equations with external force of general form in R~3, there exist nontrivial stationary solutions provided the external forces are small in suitable norms, which was studied in article[15], and there we also proved the global in time stability of the stationary solutions with respect to initial data in H~3-framework. In this article, the authors investigate the rates of convergence of nonstationary solutions to the corresponding stationary solutions when the initial data are small in H~3 and bounded in L_(6/5).

  18. Gender, threat/control-override delusions and violence.

    Science.gov (United States)

    Teasdale, Brent; Silver, Eric; Monahan, John

    2006-12-01

    This study brings together the threat/control-override perspective and the literature on gender and stress coping to argue that gender moderates the association between threat delusions and violence. We suggest that men are more likely than women to respond to stressors such as threat delusions with violence. We test these ideas using data from the MacArthur Violence Risk Assessment Study, a multi-wave study of post-discharge psychiatric patients. Within-person results from two-level hierarchical models support the idea that men and women cope with threat delusions differently. Specifically, we find that men are significantly more likely to engage in violence during periods when they experience threat delusions, compared with periods when they do not experience threat delusions. In contrast, women are significantly less likely to engage in violence during times when they experience threat delusions, compared with periods when they do not. We discuss these findings in light of the literature on gender and stress coping.

  19. Effect of aseismic ridge subduction on slab geometry and overriding plate deformation: Insights from analogue modeling

    Science.gov (United States)

    Martinod, Joseph; Guillaume, Benjamin; Espurt, Nicolas; Faccenna, Claudio; Funiciello, Francesca; Regard, Vincent

    2013-03-01

    We present analogue models simulating the subduction of a buoyant ridge oriented perpendicularly or obliquely with respect to the trench, beneath an advancing overriding plate. The convergence velocity is imposed by lateral boundary conditions in this experimental set. We analyze the three-dimensional geometry of the slab, the deformation and topography of the overriding plate. Experiments suggest that ridge subduction diminishes the dip of the slab, eventually leading to the appearance of a horizontal slab segment in case boundary conditions impose a rapid convergence. This result contrasts with that obtained in free subduction experiments, in which ridge subduction diminishes the convergence velocity which, in turn, increases the dip of the slab beneath the ridge. The slab dip decrease is accompanied by the indentation of the overriding plate by the ridge, resulting in arc curvature. Experiments suggest that indentation is larger for small convergence velocity and large slab dip. Ridge subduction also uplifts the overriding plate. Uplift first occurs close to the trench (~ fore-arc area) and is accompanied by the flexural subsidence of the overriding plate behind the uplifted area (~ back-arc subsidence). The uplifted area migrates within the overriding plate interiors following the appearance of a horizontal slab segment. These results are compared with natural examples of ridge subduction in the circum-Pacific area. They explain why ridge subduction may have contrasted effects on the overriding plate dynamics depending on the global conditions that constrain the converging system.

  20. The Effect of Minimum Wages on the Labor Force Participation Rates of Teenagers.

    Science.gov (United States)

    Wessels, Walter J.

    In light of pressure on Congress to raise the minimum wage from $5.15 to $6.15 per hour, a study looked at the effects such a raise would have on more than 10 million workers, many of them teenagers. The study used quarterly data on the labor force participation rates of teenagers from 1978 through 1999 and other studies to assess the effects of…

  1. International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wohlgemuth, J.; Kurtz, S.

    2014-10-01

    The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests are being developed for each of the selected climate zones.

  2. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease

    DEFF Research Database (Denmark)

    Rose, Martin Høyer; Løkkegaard, Annemette; Sonne-Holm, Stig

    2013-01-01

    We investigated lower-extremity isometric tremor Approximate Entropy (irregularity), torque steadiness and rate of force development (RFD) and their associations to muscle activation strategy during isometric knee extensions in patients with Parkinson's disease (PD). Thirteen male patients...... and the patients had increased muscle co-activation. A markedly lower RFD was found in PD and the decreased RFD correlated with reduced agonist muscle activation. Furthermore, patient RFD correlated with the Movement-Disorder-Society-Unified-Parkinson's-Disease-Rating-Scale 3 (motor part) scores. We concluded...

  3. The role of rate of force development on vertical jump performance.

    Science.gov (United States)

    McLellan, Christopher P; Lovell, Dale I; Gass, Gregory C

    2011-02-01

    The purpose of this study was to examine a) the relationship between rate of force development (RFD) and vertical jump (VJ) performance during a counter movement jump (CMJ), and b) the reliability of RFD recorded during the CMJ and squat jump (SJ) forms of the VJ. Twenty-three physically active men aged 23 ± 3.9 years participated in the study. Subjects completed 3 unloaded CMJ and 3 unloaded SJ in random order on a force plate. The RFD was measured during CMJ and SJ movements with vertical jump displacement (VJD) measured simultaneously during the CMJ only. Subjects incorporated arm swing to their CMJ technique to reach up as high as possible, and VJD was measured. All SJ were executed with both hands on the hips throughout the full range of movement. Peak rate of force development (PRFD), peak force (PF), and time to peak force (TPF) were significantly correlated to VJD during the CMJ (r = 0.68, r = 0.51, and r = -0.48, respectively). The RFD and TPF during the CMJ and SJ were associated with low test-retest reliability (coefficient of variation [CV]: 11.8-7.9%). Peak and average power, PF, and VJD produced high test-retest reliability (CV: 2.8-5.1%) during both the CMJ and SJ movements. Our results indicate that PRFD, a measure of explosive strength, and PF, a measure of maximal strength, are the primary contributors to VJD during the CMJ in physically active men. However, caution must be used when interpreting data using PRFD because of its low retest reliability.

  4. Reliability assessment to determine the optimal forced outage rate of components

    Directory of Open Access Journals (Sweden)

    Habib Daryabad

    2014-03-01

    Full Text Available Determining the optimal forced outage rate (FOR ofcomponents can lead to reducing the operational and maintenance costs inelectric power systems. FOR is closely associated with two factors: number ofoutages and duration of outages. Therefore, it is possible to decrease the FORthrough decreasing the number of outages or reducing the duration ofoutages. Decreasing number of outages is usually carried out throughreinforcement of the network and reducing the duration of outages is mainlyperformed through increasing the repair and maintenance groups. Both of theproposed methods to decrease the FOR possess the costs. Therefore, it is verysuitable to find the optimal rate of FOR and avoiding unnecessary costs. Thispaper presents a new methodology to find the optimal rate of FOR. In thisregard, the system reliability is assessed and evaluated from view of FOR andthe optimal rate of FOR is denoted for all components.

  5. Early and late rate of force development: differential adaptive responses to resistance training?

    Science.gov (United States)

    Andersen, L L; Andersen, J L; Zebis, M K; Aagaard, P

    2010-02-01

    The objective of this study is to investigate the potentially opposing influence of qualitative and quantitative muscular adaptations in response to high-intensity resistance training on contractile rate of force development (RFD) in the early (200 ms) of rising muscle force. Fifteen healthy young males participated in a 14-week resistance training intervention for the lower body and 10 matched subjects participated as controls. Maximal muscle strength (MVC) and RFD were measured during maximal voluntary isometric contraction of the quadriceps femoris muscle. Muscle biopsies were obtained from the vastus lateralis. The main findings were that RFD in the late phase of rising muscle force increased in response to resistance training whereas early RFD remained unchanged and early relative RFD (i.e., RFD/MVC) decreased. Quantitatively, muscle fiber cross-sectional area and MVC increased whereas, qualitatively, the relative proportion of type IIX muscle fibers decreased. Multiple regression analysis showed that while increased MVC positively influenced both early and late RFD, decreased-type IIX negatively influenced early RFD only. In conclusion, early and late RFD responded differently to high-intensity resistance training due to differential influences of qualitative and quantitative muscular adaptations on early and later phases of rising muscle force.

  6. Labour force participation rates at the regional and national levels of the European Union : An integrated analysis

    NARCIS (Netherlands)

    Elhorst, J. Paul; Zeilstra, Annette S.

    2007-01-01

    This study investigates the causes of variation in regional labour force participation rates in a cross-country perspective. A microeconomic framework of the tabour force participation decision is aggregated across individuals to obtain an explanatory rnodel of regional participation rates in which

  7. The effect of stretch rate and activation state on skeletal muscle force in the anatomical range.

    Science.gov (United States)

    Grover, Joel P; Corr, David T; Toumi, Hechmi; Manthei, David M; Oza, Ashish L; Vanderby, Ray; Best, Thomas M

    2007-03-01

    The effects of stretch rate and activation state on muscle mechanics require further clarification. This subject is of particular interest because of the role of skeletal muscle undergoing eccentric contractions in musculoskeletal injuries. The present study investigated the force-displacement behavior of rabbit tibialis anterior muscle at three stretch rates (2.5, 10, 25 cm/s) and three activation states (passive, tetanic, denervated). A phenomenological power law model and a dynamic systems model were used to describe the mechanical responses. The power law model showed excellent agreement with the passive and denervated responses to stretch (R(mean)=0.97). Repeated measures analysis of variance found a difference (P=0.042) in peak force between the passive and denervated states at a stretch rate of 2.5 cm/s. The dynamic systems model closely fit the tetanized muscle responses (R(mean)=0.95). There was no difference in the displacement at yield (P=0.83) for the three stretch rates of the tetanized muscle undergoing stretch. Differences between the passive and denervated responses suggest that mechanoreceptors may play a role in stimulating the muscle as it is stretched through the anatomical range. The displacement at yield did not change significantly over a decade range of stretch velocities, suggesting that a strain threshold exists beyond which cross bridges cannot remain bound. The power law and dynamic systems models presented offer mathematically tractable approaches to interpret the response of lengthening skeletal muscle. These findings on active, passive, and denervated muscle point to a possible role of the muscle spindle to tissue mechanical behavior that should be accounted for in future studies of force-elongation behavior of skeletal muscle.

  8. Effect of aseismic ridge subduction on slab geometry and overriding plate deformation: Insights from analogue modeling

    OpenAIRE

    Martinod, Joseph; Guillaume, Benjamin; Espurt, Nicolas; Faccenna, Claudio; Funiciello, Francesca; Regard, Vincent

    2013-01-01

    International audience; We present analogue models simulating the subduction of a buoyant ridge beneath an advancing overriding plate whose velocity is imposed by lateral boundary conditions. We analyze the 3D geometry of the slab, the deformation and topography of the overriding plate. Ridge subduction diminishes the dip of the slab, eventually leading to the appearance of a horizontal slab segment. This result contrasts with that obtained in free subduction experiments, in which ridge subdu...

  9. DESIGN THEORY FOR G-π BRIDGERELIEF VALVE WITH ZERO OVERRIDE

    Institute of Scientific and Technical Information of China (English)

    Hu Yanping; Huang Zhichu; Liu Deshun; Mao Zhengyu

    2004-01-01

    A new construction of the relief valve is presented with pilot G-( bridg hydraulic resistances network. The design theory of G-( bridge relief valve is studied and the formulas for designing the relief valve with zero static pressure override are obtained. The static performances of the relief valve are experimentally investigated. The theoretical and experimental results show that the static pressure override of the developed relief valve can be zero, i.e. when the overflow increases the control pressure is kept constant.

  10. A comparison of methods for determining the rate of force development during isometric midthigh clean pulls.

    Science.gov (United States)

    Haff, G Gregory; Ruben, Ryan P; Lider, Joshua; Twine, Corey; Cormie, Prue

    2015-02-01

    Twelve female division I collegiate volleyball players were recruited to examine the reliability of several methods for calculating the rate of force development (RFD) during the isometric midthigh clean pull. All subjects were familiarized with the isometric midthigh clean pull and participated in regular strength training. Two isometric midthigh clean pulls were performed with 2 minutes rest between each trail. All measures were performed in a custom isometric testing device that included a step-wise adjustable bar and a force plate for measuring ground reaction forces. The RFD during predetermined time zone bands (0-30, 0-50, 0-90, 0-100, 0-150, 0-200, and 0-250 milliseconds) was then calculated by dividing the force at the end of the band by the band's time interval. The peak RFD was then calculated with the use of 2, 5, 10, 20, 30, and 50 milliseconds sampling windows. The average RFD (avgRFD) was calculated by dividing the peak force (PF) by the time to achieve PF. All data were analyzed with the use of intraclass correlation alpha (ICCα) and the coefficient of variation (CV) and 90% confidence intervals. All predetermined RFD time bands were deemed reliable based on an ICCα >0.95 and a CV <4%. Conversely, the avgRFD failed to meet the reliability standards set for this study. Overall, the method used to assess the RFD during an isometric midthigh clean pull impacts the reliability of the measure and predetermined RFD time bands should be used to quantify the RFD.

  11. A rate adaptive control method for Improving the imaging speed of atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanyan [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, 300072 Tianjin (China); Tianjin Key Laboratory of Information Sensing and Intelligent Control, Tianjin University of Technology and Education, 300222 Tianjin (China); Wan, Jiahuan [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, 300072 Tianjin (China); Hu, Xiaodong, E-mail: xdhu@tju.edu.cn [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, 300072 Tianjin (China); Xu, Linyan; Wu, Sen; Hu, Xiaotang [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, 300072 Tianjin (China)

    2015-08-15

    A simple rate adaptive control method is proposed to improve the imaging speed of the atomic force microscope (AFM) in the paper. Conventionally, the probe implemented on the AFM scans the sample surface at a constant rate, resulting in low time efficiency. Numerous attempts have been made to realize high-speed AFMs, while little efforts are put into changing the constant-rate scanning. Here we report a rate adaptive control method based on variable-rate scanning. The method automatically sets the imaging speed for the x scanner through the analysis of the tracking errors in the z direction at each scanning point, thus improving the dynamic tracking performance of the z scanner. The development and functioning of the rate adaptive method are demonstrated, as well as how the approach significantly achieves faster scans and a higher resolution AFM imaging. - Highlights: • A rate adaptive control method is proposed to improve the imaging speed ofAFM. • The new method automatically selects appropriate scanning speed in the x direction through the analysis of the tracking errors in the z direction. • The system identification is carried out to obtain the mathematical model of thevertical feedback system of AFM.

  12. Convergence Rate to Stationary Solutions for Boltzmann Equation with External Force

    Institute of Scientific and Technical Information of China (English)

    Seiji UKAI; Tong YANG; Huijiang ZHAO

    2006-01-01

    For the Boltzmann equation with an external force in the form of the gradient of a potential function in space variable, the stability of its stationary solutions as local Maxwellians was studied by S. Ukai et al. (2005) through the energy method. Based on this stability analysis and some techniques on analyzing the convergence rates to stationary solutions for the compressible Navier-Stokes equations, in this paper, we study the convergence rate to the above stationary solutions for the Boltzmann equation which is a fundamental equation in statistical physics for non-equilibrium rarefied gas. By combining the dissipation from the viscosity and heat conductivity on the fluid components and the dissipation on the non-fluid component through the celebrated H-theorem, a convergence rate of the same order as the one for the compressible Navier-Stokes is obtained by constructing some energy functionals.

  13. Effect of Sampling Rates on the Quantification of Forces, Durations, and Rates of Loading of Simulated Side Posture High-Velocity, Low-Amplitude Lumbar Spine Manipulation☆

    Science.gov (United States)

    Gudavalli, Maruti Ram; DeVocht, James; Tayh, Ali; Xia, Ting

    2013-01-01

    Objective Quantification of chiropractic high-velocity, low-amplitude spinal manipulation (HVLA-SM) may require biomechanical equipment capable of sampling data at high rates. However, there are few studies reported in the literature regarding the minimal sampling rate required to record the HVLA-SM force-time profile data accurately and precisely. The purpose of this study was to investigate the effect of different sampling rates on the quantification of forces, durations, and rates of loading of simulated side posture lumbar spine HVLA-SM delivered by doctors of chiropractic. Methods Five doctors of chiropractic (DCs) and 5 asymptomatic participants were recruited for this study. Force-time profiles were recorded during (i) 52 simulated HVLA-SM thrusts to a force transducer placed on a force plate by 2 DCs and (ii) 12 lumbar side posture HVLA-SM on 5 participants by 3 DCs. Data sampling rate of the force plate remained the same at 1000 Hz, whereas the sampling rate of the force transducer varied at 50, 100, 200, and 500 Hz. The data were reduced using custom-written MATLAB (Mathworks, Inc, Natick, MA) and MathCad (version 15; Parametric Technologies, Natick, MA) programs and analyzed descriptively. Results The average differences in the computed durations and rates of loading are smaller than 5% between 50 and 1000 Hz sampling rates. The differences in the computed preloads and peak loads are smaller than 3%. Conclusions The small differences observed in the characteristics of force-time profiles of simulated manual HVLA-SM thrusts measured using various sampling rates suggest that a sampling rate as low as 50 to 100 Hz may be sufficient. The results are applicable to the manipulation performed in this study: manual side posture lumbar spine HVLA-SM. PMID:23790603

  14. Effect of sampling rates on the quantification of forces, durations, and rates of loading of simulated side posture high-velocity, low-amplitude lumbar spine manipulation.

    Science.gov (United States)

    Gudavalli, Maruti Ram; DeVocht, James; Tayh, Ali; Xia, Ting

    2013-06-01

    Quantification of chiropractic high-velocity, low-amplitude spinal manipulation (HVLA-SM) may require biomechanical equipment capable of sampling data at high rates. However, there are few studies reported in the literature regarding the minimal sampling rate required to record the HVLA-SM force-time profile data accurately and precisely. The purpose of this study was to investigate the effect of different sampling rates on the quantification of forces, durations, and rates of loading of simulated side posture lumbar spine HVLA-SM delivered by doctors of chiropractic. Five doctors of chiropractic (DCs) and 5 asymptomatic participants were recruited for this study. Force-time profiles were recorded during (i) 52 simulated HVLA-SM thrusts to a force transducer placed on a force plate by 2 DCs and (ii) 12 lumbar side posture HVLA-SM on 5 participants by 3 DCs. Data sampling rate of the force plate remained the same at 1000 Hz, whereas the sampling rate of the force transducer varied at 50, 100, 200, and 500 Hz. The data were reduced using custom-written MATLAB (Mathworks, Inc, Natick, MA) and MathCad (version 15; Parametric Technologies, Natick, MA) programs and analyzed descriptively. The average differences in the computed durations and rates of loading are smaller than 5% between 50 and 1000 Hz sampling rates. The differences in the computed preloads and peak loads are smaller than 3%. The small differences observed in the characteristics of force-time profiles of simulated manual HVLA-SM thrusts measured using various sampling rates suggest that a sampling rate as low as 50 to 100 Hz may be sufficient. The results are applicable to the manipulation performed in this study: manual side posture lumbar spine HVLA-SM. Copyright © 2013 The Authors. Published by Mosby, Inc. All rights reserved.

  15. Age-related decreases in motor unit discharge rate and force control during isometric plantar flexion

    DEFF Research Database (Denmark)

    Kallio, J; Søgaard, Karen; Avela, J

    2012-01-01

    Aging is related to multiple changes in muscle physiology and function. Previous findings concerning the effects of aging on motor unit discharge rate (DR) and fluctuations in DR and force are somewhat contradictory. Eight YOUNG and nine OLD physically active males performed isometric ramp (RECR......) and isotonic (ISO) plantar flexions at 10 and 20% of surface EMG at MVC. Motor unit (MU) action potentials were recorded with intramuscular fine-wire electrodes and decomposed with custom build software "Daisy". DR was lower in OLD in RECR-10% (17.9%, p...

  16. Resistance training for explosive and maximal strength: effects on early and late rate of force development.

    Science.gov (United States)

    Oliveira, Felipe B D; Oliveira, Anderson S C; Rizatto, Guilherme F; Denadai, Benedito S

    2013-01-01

    The aim of the present study was to verify whether strength training designed to improve explosive and maximal strength would influence rate of force development (RFD). Nine men participated in a 6-week knee extensors resistance training program and 9 matched subjects participated as controls. Throughout the training sessions, subjects were instructed to perform isometric knee extension as fast and forcefully as possible, achieving at least 90% maximal voluntary contraction as quickly as possible, hold it for 5 s, and relax. Fifteen seconds separated each repetition (6-10), and 2 min separated each set (3). Pre- and post-training measurements were maximal isometric knee extensor (MVC), RFD, and RFD relative to MVC (i.e., %MVC·s(-1)) in different time-epochs varying from 10 to 250 ms from the contraction onset. The MVC (Nm) increased by 19% (275.8 ± 64.9 vs. 329.8 ± 60.4, p force can be differently influenced by resistance training. Thus, the resistance training programs should consider the specific neuromuscular demands of each sport.In active non-strength trained individuals, a short-term resistance training program designed to increase both explosive and maximal strength seems to reduce the adaptive response (i.e. increased RFDMAX) evoked by training with an intended ballistic effort (i.e. high-RFD contraction).

  17. Increase in rate of force development with skin cooling during isometric knee extension.

    Science.gov (United States)

    Shimose, Ryota; Ushigome, Nobuyuki; Tadano, Chigaya; Sugawara, Hitoshi; Yona, Masae; Matsunaga, Atsuhiko; Muro, Masuo

    2014-12-01

    Rate of force development (RFD) plays an important role when performing rapid and forceful movements. Cold-induced afferent input with transient skin cooling (SC) can modulate neural drive. However, the relationship between RFD and SC is unknown. The purpose of this study was to investigate whether SC increases RFD during isometric knee extension. Fifteen young healthy men (25 ± 8 yrs old) contracted their quadriceps muscle as fast and forcefully as possible with or without SC. Skin cooling was administered to the front of the thigh. Torque and electromyographic activity were measured simultaneously. Peak torque was not affected by SC. Skin cooling induced a significant increase in RFD at the phase 0-30 and 0-50 ms. The root mean square of the electromyography of vastus medialis, rectus femoris and vastus lateralis at the phases 0-30-50-100 ms increased significantly or tended to increase with SC. These results suggest that SC may increase neural drive and improve RFD in the very early phases of contraction.

  18. Age-related decline in the rate of force development scaling factor.

    Science.gov (United States)

    Bellumori, Maria; Jaric, Slobodan; Knight, Christopher A

    2013-10-01

    Physical quickness is less in older adults with implications for fall prevention, movement initiation, and activities of daily living. The purpose was to compare control of rapid contractions in young and older adults within two diverse muscle groups: powerful elbow extensors (EE) and dexterous index finger abductors (IFA). Most-rapid force pulses to a variety of levels were recorded and peak force and rate of force development (RFD) were analyzed with linear regression. The resulting slope represents the dependent variable of interest, the RFD-scaling factor (RFD-SF). RFD-SF of EE and IFA strongly correlated both overall (r = .87, p < .01) and separately in young (r = .60, p < .05) and older (r = .77, p < .01) adults. RFD-SF values were different between muscle groups (F1,28 = 19.1, p < .001) and also less in elderly (F1,28 = 32.6, p < .001). We conclude that RFD-SF provides a sensitive assessment of muscle quickness that can be used to evaluate neuromuscular function in aging humans.

  19. Are early and late rate of force development differently influenced by fast-velocity resistance training?

    Science.gov (United States)

    de Oliveira, Felipe B D; Rizatto, Guilherme F; Denadai, Benedito S

    2013-07-01

    This study examined the effect of fast-velocity concentric isokinetic resistance training (FV) on the rate of force development (RFD) at early (100 ms) of rising muscle force. Nine men participated in a 6-week resistance training intervention for the lower body, and nine matched subjects participated as controls (CON). During concentric isokinetic (180°s(-1)) knee extension training, subjects were instructed to do each contraction 'as fast and forcefully as possible'. Maximal muscle strength (MVC) and RFD (0-10, 0-20, …, 0-250 ms from the onset of contraction) were measured during maximal voluntary isometric contraction of the knee extensors (KE). There were no significant changes in MVC of KE in both groups after intervention (FV = 314·2 ± 101·1 versus 338·7 ± 88·0 N∙m, P>0·05; CON = 293·3 ± 94·8 versus 280·0 ± 72·2 N∙m, P>0·05). The RFD increased 39-71% at time intervals up to 90 ms from the onset of the contraction (Pforce.

  20. Importance of anisotropy in detachment rates for force production and cargo transport by a team of motor proteins.

    Science.gov (United States)

    Takshak, Anjneya; Kunwar, Ambarish

    2016-05-01

    Many cellular processes are driven by collective forces generated by a team consisting of multiple molecular motor proteins. One aspect that has received less attention is the detachment rate of molecular motors under mechanical force/load. While detachment rate of kinesin motors measured under backward force increases rapidly for forces beyond stall-force; this scenario is just reversed for non-yeast dynein motors where detachment rate from microtubule decreases, exhibiting a catch-bond type behavior. It has been shown recently that yeast dynein responds anisotropically to applied load, i.e. detachment rates are different under forward and backward pulling. Here, we use computational modeling to show that these anisotropic detachment rates might help yeast dynein motors to improve their collective force generation in the absence of catch-bond behavior. We further show that the travel distance of cargos would be longer if detachment rates are anisotropic. Our results suggest that anisotropic detachment rates could be an alternative strategy for motors to improve the transport properties and force production by the team.

  1. The rate of force development scaling factor (RFD-SF): protocol, reliability, and muscle comparisons.

    Science.gov (United States)

    Bellumori, Maria; Jaric, Slobodan; Knight, Christopher A

    2011-07-01

    Performing a set of isometric muscular contractions to varied amplitudes with instructions to generate force most rapidly reveals a strong linear relationship between peak forces (PF) achieved and corresponding peak rates of force development (RFD). The slope of this relationship, termed the RFD scaling factor (RFD-SF), quantifies the extent to which RFD scales with contraction amplitude. Such scaling allows relative invariance in the time required to reach PF regardless of contraction size. Considering the increasing use of this relationship to study quickness and consequences of slowness in older adults and movement disorders, our purpose was to further develop the protocol to measure RFD-SF. Fifteen adults (19-28 years) performed 125 rapid isometric contractions to a variety of force levels in elbow extensors, index finger abductors, and knee extensors, on 2 days. Data were used to determine (1) how the number of pulses affects computation of the RFD-SF, (2) day-to-day reliability of the RFD-SF, and (3) the nature of RFD-SF differences between diverse muscle groups. While sensitive to the number of pulses used in its computation (P50 pulses (ICC>.7) and more so with 100-125 pulses (ICC=.8-.92). Despite differences in size and function across muscles, RFD-SF was generally similar (i.e., only 8.5% greater in elbow extensors than in index finger abductors and knee extensors; P=.049). Results support this protocol as a reliable means to assess how RFD scales with PF in rapid isometric contractions as well as a simple, non-invasive probe into neuromuscular health.

  2. Optimal decay rate of vibrating beam equations controlled by combined boundary feedback forces

    Institute of Scientific and Technical Information of China (English)

    于景元; 李胜家; 王耀庭; 粱展东

    1999-01-01

    The optimal decay rate problem is considered for boundary control system modeling by a flexible structure consisting of a Eular-Bernoulli beam. Controls are a bending moment in proportion to angular velocity and a shear force in proportion to velocity. A sensitivity asymptotic analysis of the system’ s eigenvalues and eigenfunctions is set up. It is proved that, for every 00, y(0)=Y0, Y0=(Y1,Y2)T ∈V×H form a Riesz basis of V×H, and the optimal exponential decay rate can be obtained from the spectrum of the system.

  3. Associated decrements in rate of force development and neural drive after maximal eccentric exercise.

    Science.gov (United States)

    Farup, J; Rahbek, S K; Bjerre, J; de Paoli, F; Vissing, K

    2016-05-01

    The present study investigated the changes in contractile rate of force development (RFD) and the neural drive following a single bout of eccentric exercise. Twenty-four subjects performed 15 × 10 maximal isokinetic eccentric knee extensor contractions. Prior to and at 24, 48, 72, 96, and 168 h during post-exercise recovery, isometric RFD (30, 50 100, and 200 ms), normalized RFD [1/6,1/2, and 2/3 of maximal voluntary contraction (MVC)] and rate of electromyography rise (RER; 30, 50, and 75 ms) were measured. RFD decreased by 28-42% peaking at 48 h (P eccentric exercise. This association suggests that exercise-induced decrements in RFD can, in part, be explained decrements in neural drive. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease.

    Science.gov (United States)

    Rose, Martin H; Løkkegaard, Annemette; Sonne-Holm, Stig; Jensen, Bente R

    2013-04-01

    We investigated lower-extremity isometric tremor Approximate Entropy (irregularity), torque steadiness and rate of force development (RFD) and their associations to muscle activation strategy during isometric knee extensions in patients with Parkinson's disease (PD). Thirteen male patients with idiopathic PD and 15 neurologically healthy matched controls performed isometric maximal contractions (extension/flexion) as well as steady submaximal and powerful isometric knee extensions. The patients with PD showed decreased isometric tremor irregularity. Torque steadiness was reduced in PD and the patients had increased muscle coactivation. A markedly lower RFD was found in PD and the decreased RFD correlated with reduced agonist muscle activation. Furthermore, patient RFD correlated with the Movement-Disorder-Society-Unified-Parkinson's-Disease-Rating-Scale 3 (motor part) scores. We concluded that both knee isometric tremor Approximate Entropy and torque steadiness clearly differentiate between patients with PD and healthy controls. Furthermore, severely compromised RFD was found in patients with PD and was associated with decreased agonist muscle activation.

  5. Modelling nonlinear behavior of labor force participation rate by STAR: An application for Turkey

    Directory of Open Access Journals (Sweden)

    Sibel Cengiz

    2014-04-01

    Full Text Available The aim of this paper is to contribute to the understanding of the behavior of participation rates in terms of gender differences. We employed smooth autoregressive transition models for the quarterly Turkish labor force participation rates (LFPR data between 2000: Q1 - 2011: Q4 to present an asymmetric participation behavior. The smoothness parameter indicates a gradual transition from low to high regimes. It is higher for female workers compared to the male workers. Participation rates diminish during a recession but they increase smoothly during the periods of expansion. The estimation results of Enders et al. (1998 also verified the asymmetry and nonlinearity in participation rates. During periods of economic expansion, they are higher than the threshold but the low regime indicator function takes the value zero. The results of the paper have economic implications for policy makers. Due to the discouraged worker and added worker effects, LFPR should be observed with the unemployment rates while evaluating the tightness of the labor market.

  6. The acute effects of static stretching on peak force, peak rate of force development and muscle activity during single- and multiple-joint actions in older women.

    Science.gov (United States)

    Gonçalves, Raquel; Gurjão, André Luiz Demantova; Jambassi Filho, José Claudio; Farinatti, Paulo De Tarso Veras; Gobbi, Lilian Teresa Bucken; Gobbi, Sebastião

    2013-01-01

    The present study investigated the acute effects of static stretching on peak force, peak rate of force development and integrated electromyography (iEMG) in 27 older women (65 ± 4 years; 69 ± 9 kg; 157 ± 1 cm; 28 ± 4 kg · m(-2)). The participants were tested during two exercises (leg press and knee extension) after two conditions: stretching and control. The data were collected on four days (counterbalanced with a 24-hour rest period). In the stretching condition, the quadriceps muscle was stretched (knee flexion) for three sets of 30 s with 30 s rest intervals. No significant difference was detected for peak force and peak rate of force development during the single- and multiple-joint exercises, regardless of the following interactions: condition (stretching and control) vs. time (pre x post x 10 x 20 x 30 minutes post; P > 0.05) and exercise vs. time (P > 0.05). Additionally, no significant interaction was found for the iEMG activity (condition vs. time; P > 0.05) in the single- and multiple-joint exercises. In conclusion, a small amount of stretching of an agonist muscle (quadriceps) did not affect the peak force, peak rate of force development and EMG activity in older women during single- and multiple-joint exercises.

  7. Description and Rate of Musculoskeletal Injuries in Air Force Basic Military Trainees, 2012-2014.

    Science.gov (United States)

    Nye, Nathaniel S; Pawlak, Mary T; Webber, Bryant J; Tchandja, Juste N; Milner, Michelle R

    2016-11-01

     Musculoskeletal injuries are common in military trainees and have significant medical and operational effects.  To provide current musculoskeletal injury epidemiology data for US Air Force basic military trainees.  Descriptive epidemiologic study with cross-sectional features.  US Air Force Basic Military Training, Joint Base San Antonio-Lackland, Texas.  All recruits who entered training between July 1, 2012, and June 30, 2014.  Incidence density rate of all musculoskeletal injuries (stratified by body region and type) and factors and costs associated with injuries.  Of the 67 525 trainees, 12.5% sustained 1 or more musculoskeletal injuries. The overall incidence density rate was 18.3 injuries per 1000 person-weeks (15.1 for men and 29.4 for women). The most common diagnosis (n = 2984) was Pain in joint, lower leg, as described in the International Classification of Diseases, Ninth Revision, Clinical Modification, code 719.46. Injuries were more common among those with lower levels of baseline aerobic and muscular fitness. Injured trainees were 3.01 times (95% confidence interval = 2.85, 3.18) as likely to be discharged, and injured trainees who did graduate were 2.88 times (95% confidence interval = 2.72, 3.04) as likely to graduate late. During the surveillance period, injuries resulted in more than $43.7 million in medical ($8.7 million) and nonmedical ($35 million) costs.  Musculoskeletal injuries, predominantly of the lower extremities, have significant fiscal and operational effects on Air Force Basic Military Training. Further research into prevention and early rehabilitation of these injuries in military trainees is warranted.

  8. Four Weeks of finger grip training increases the rate of force development and the maximal force in elite and world-top ranking climbers.

    Science.gov (United States)

    Levernier, Guillaume; Laffaye, Guillaume

    2017-09-19

    The goal of this study was to assess the impact of a specific four-week training program on finger grip in climbers; specifically, on the maximal force and the rate of force development (RFD) of finger muscles in isometric contraction. The participants were 14 French male rock climbers who took part in national and international bouldering competitions (at world-ranking and elite levels). They were divided into two samples. The experimental group performed a specific four-week training program that included such exercises as suspensions on small holds at the rate of three times a week. The control group performed climbing exercises only. The maximal force and the RFD were recorded using a specific dynamometer in three different holding conditions (slope crimp, half crimp and full crimp). Results reveal a significant gain of force for the slope crimp (+ 8 %) and a high increase of the RFD in the first 200ms of the force-time slope (between 27.5 % and 32 % for averaged conditions), suggesting a neural gain rather a change in muscle-tendon structure. These results reveals that a four-week training program is enough to improve the level of maximum force and rate of force development in elite climbers. Bearing in mind that climbing will make its appearance in a future Olympic Games in the form of a combined competition, i.e., bouldering, speed climbing and lead climbing, it will be crucial for each athlete to develop both a high level of force and RFD to be competitive.

  9. Detailed description of exclusive muon capture rates using realistic two-body forces

    CERN Document Server

    Giannaka, P G

    2015-01-01

    Starting from state-by-state calculations of exclusive rates of the ordinary muon capture (OMC), we evaluated total muon-capture rates for a set of light- and medium-weight nuclear isotopes. We employed a version of the proton-neutron quasi-particle random phase approximation (pn-QRPA, for short) which uses as realistic nuclear forces the Bonn C-D one boson exchange potential. Special attention was paid on the percentage contribution to the total muon-capture rate of specific low-spin multipolarities resulting by summing over the corresponding multipole transitions. The nuclear method used offers the possibility of estimating separately the individual contributions to the total and partial rates of the polar-vector and axial-vector components of the weak interaction Hamiltonian for each accessible final state of the daughter nucleus. One of our main goals is to provide a reliable description of the charge changing transitions matrix elements entering the description of other similar semileptonic nuclear proce...

  10. Subthalamic nucleus and internal globus pallidus scale with the rate of change of force production in humans.

    Science.gov (United States)

    Vaillancourt, David E; Mayka, Mary A; Thulborn, Keith R; Corcos, Daniel M

    2004-09-01

    The basal ganglia, motor cortex, and cerebellum have been implicated as a circuit that codes for movement velocity. Since movement velocity covaries with the magnitude of force exerted and previous studies have shown that similar regions scale in activation for velocity and force, the scaling of neuronal activity with movement velocity could be due to the force exerted. The present study implemented a parametric functional magnetic resonance imaging (fMRI) design to determine which brain regions directly scale with the rate of change of force production, independent of the magnitude of force exerted. Nine healthy adults produced force with their right middle finger and thumb at 25% of their maximal voluntary contraction across four conditions: (1) fast pulse, (2) fast hold, (3) medium hold, and (4) slow hold. There were three primary findings: (i) the activation volume in multiple regions increased with the duration of the force contraction, (ii) only the activation volume in the bilateral internal globus pallidus and left subthalamic nucleus parametrically scaled with the rate of change of force production, and (iii) there was an inverse relation between the activation volume in the subthalamic nucleus and internal globus pallidus with the rate of change of force production. The current findings are the first to have used neuroimaging techniques in humans to segregate the functional anatomy of the internal globus pallidus from external globus pallidus, distinguish functional activation in the globus pallidus from the putamen, and demonstrate task-dependent scaling in the subthalamic nucleus and internal globus pallidus. We conclude that fast, ballistic force production is preprogrammed, requiring a small metabolic demand from the basal ganglia. In contrast, movements that require the internal regulation of the rate of change of force are associated with increased metabolic demand from the subthalamic nucleus and internal segment of the globus pallidus.

  11. Precipitation rate spectra as dependent on dynamic forcing: application to probabilistic forecasting

    Directory of Open Access Journals (Sweden)

    A. R. Ivanova

    2007-04-01

    Full Text Available Occurrence frequencies, OF, of 12-h precipitation amounts, P, at stations in the former European USSR are displayed as dependent on dynamic forcing of vertical motions. The dynamic forcing is described by a "frontal parameter", F (calculated in the points of objective analysis grid, which depends on the surface pressure field curvature and on the baroclinicity in the lower half of the troposphere. The precipitation rate spectra for 4 seasons, calculated from a large sample of data (7 years, about 650 000 values of P for one season, show a monotonous OF growth of all ranges of P>1 mm/12 h with F increase. The growth is especially significant for heavy precipitation. As a result, F is shown to be an informative predictor of P spectrum or of probability of any given range of P. As a next step, two-dimensional spectra of precipitation occurrence frequency, as a function of F and LNB, that is, OF (F, LNB, are calculated, LNB being the level of neutral buoyancy at the gridpoint, an estimate of grid-scale convective instability. On this basis, an approach to probabilistic forecasting is suggested.

  12. Motor unit rate coding is severely impaired during forceful and fast muscular contractions in individuals post stroke.

    Science.gov (United States)

    Chou, Li-Wei; Palmer, Jacqueline A; Binder-Macleod, Stuart; Knight, Christopher A

    2013-06-01

    Information regarding how motor units are controlled to produce forces in individuals with stroke and the mechanisms behind muscle weakness and movement slowness can potentially inform rehabilitation strategies. The purpose of this study was to describe the rate coding mechanism in individuals poststroke during both constant (n = 8) and rapid (n = 4) force production tasks. Isometric ankle dorsiflexion force, motor unit action potentials, and surface electromyography were recorded from the paretic and nonparetic tibialis anterior. In the paretic limb, strength was 38% less and the rate of force development was 63% slower. Linear regression was used to describe and compare the relationships between motor unit and electromyogram (EMG) measures and force. During constant force contractions up to 80% maximal voluntary contraction (MVC), rate coding was compressed and discharge rates were lower in the paretic limb. During rapid muscle contractions up to 90% MVC, the first interspike interval was prolonged and the rate of EMG rise was less in the paretic limb. Future rehabilitation strategies for individuals with stroke could focus on regaining these specific aspects of motor unit rate coding and neuromuscular activation.

  13. Dissociation rates from single-molecule pulling experiments under large thermal fluctuations or large applied force.

    Science.gov (United States)

    Abkenar, Masoud; Gray, Thomas H; Zaccone, Alessio

    2017-04-01

    Theories that are used to extract energy-landscape information from single-molecule pulling experiments in biophysics are all invariably based on Kramers' theory of the thermally activated escape rate from a potential well. As is well known, this theory recovers the Arrhenius dependence of the rate on the barrier energy and crucially relies on the assumption that the barrier energy is much larger than k_{B}T (limit of comparatively low thermal fluctuations). As was shown already in Dudko et al. [Phys. Rev. Lett. 96, 108101 (2006)PRLTAO0031-900710.1103/PhysRevLett.96.108101], this approach leads to the unphysical prediction of dissociation time increasing with decreasing binding energy when the latter is lowered to values comparable to k_{B}T (limit of large thermal fluctuations). We propose a theoretical framework (fully supported by numerical simulations) which amends Kramers' theory in this limit and use it to extract the dissociation rate from single-molecule experiments where now predictions are physically meaningful and in agreement with simulations over the whole range of applied forces (binding energies). These results are expected to be relevant for a large number of experimental settings in single-molecule biophysics.

  14. Fast sweep-rate plastic Faraday force magnetometer with simultaneous sample temperature measurement.

    Science.gov (United States)

    Slobinsky, D; Borzi, R A; Mackenzie, A P; Grigera, S A

    2012-12-01

    We present a design for a magnetometer capable of operating at temperatures down to 50 mK and magnetic fields up to 15 T with integrated sample temperature measurement. Our design is based on the concept of a Faraday force magnetometer with a load-sensing variable capacitor. A plastic body allows for fast sweep rates and sample temperature measurement, and the possibility of regulating the initial capacitance simplifies the initial bridge balancing. Under moderate gradient fields of ~1 T/m our prototype performed with a resolution better than 1 × 10(-5) emu. The magnetometer can be operated either in a dc mode, or in an oscillatory mode which allows the determination of the magnetic susceptibility. We present measurements on Dy(2)Ti(2)O(7) and Sr(3)Ru(2)O(7) as an example of its performance.

  15. SU-E-T-84: A Survey On Radiotherapy Table Tolerances and Couch Overrides of Over 350 Institutions

    Energy Technology Data Exchange (ETDEWEB)

    Chinsky, B; Patel, R; Panfil, J; Surucu, M; Roeske, J [Loyola University Medical Center, Maywood, IL (United States)

    2015-06-15

    Purpose: Table overrides are relatively common in radiotherapy, yet are a potential safety concern. The goal of this study was to survey current departmental policies on treatment couch overrides and table tolerance values used clinically. Methods: A 25 question electronic survey on couch overrides and tolerances was sent to full members of the AAPM. In the first part of the survey, participants were asked: if table overrides were allowed at their institution, who was allowed to perform these overrides, and if imaging was required with overrides. In the second part of the survey, individuals were asked to provide table tolerance data for the following sites: brain/head & neck, lung, breast, abdomen/pelvis and prostate. Each site was further divided into IMRT/VMAT and 3D conformal techniques. Free-text spaces were provided, allowing respondents to enter any table tolerance data they were unable to specify under the treatment sites listed. Results: A total of 361 individuals responded, of which approximately half participated in the couch tolerances portion of the survey. Overall, 86% of respondents’ institutions allow couch tolerance overrides at treatment. Therapists were the most common staff members permitted to perform overrides, followed by physicists, dosimetrists, and physicians, respectively. Of the institutions allowing overrides, 34% reported overriding daily. More than half of the centers require documentation of the override and/or a setup image (acquired after override) to radiographically verify the treatment site. With respect to table tolerances, groups resulting from the free-text responses were at the two extremes; SRS/SBRT were the tightest, while clinical setup/mets/extremities were the most generous. There was no qualitative difference between IMRT/VMAT and 3D conformal table tolerances. Conclusion: This work is intended to stimulate a discussion within the radiotherapy community. This discussion, supplemented by the survey results provides an

  16. Rate of Force Development, Muscle Architecture, and Performance in Young Competitive Track and Field Throwers.

    Science.gov (United States)

    Zaras, Nikolaos D; Stasinaki, Angeliki-Nikoletta E; Methenitis, Spyridon K; Krase, Argyro A; Karampatsos, Giorgos P; Georgiadis, Giorgos V; Spengos, Konstantinos M; Terzis, Gerasimos D

    2016-01-01

    The rate of force development (RFD) is an essential component for performance in explosive activities, although it has been proposed that muscle architectural characteristics might be linked with RFD and power performance. The purpose of the study was to investigate the relationship between RFD, muscle architecture, and performance in young track and field throwers. Twelve young track and field throwers completed 10 weeks of periodized training. Before (T1) and after (T2) training performance was evaluated in competitive track and field throws, commonly used shot put tests, isometric leg press RFD, 1 repetition maximum (1RM) strength as well as vastus lateralis architecture and body composition. Performance in competitive track and field throwing and the shot put test from the power position increased by 6.76 ± 4.31% (p Rate of force development and 1RM strength also increased (p ≤ 0.05). Vastus lateralis thickness and fascicle length increased by 5.95 ± 7.13% (p = 0.012) and 13.41 ± 16.15% (p = 0.016), respectively. Significant correlations were found at T1 and T2, between performance in the shot put tests and both RFD and fascicle length (p ≤ 0.05). Close correlations were found between RFD, muscle thickness, and fascicle length (p ≤ 0.05). Significant correlations were found between the % changes in lean body mass and the % increases in RFD. When calculated together, the % increase in muscle thickness and RFD could predict the % increase in shot put throw test from the power position (p = 0.019). These results suggest that leg press RFD may predict performance in shot put tests that are commonly used by track and field throwers.

  17. Cross-bridge versus thin filament contributions to the level and rate of force development in cardiac muscle.

    Science.gov (United States)

    Regnier, M; Martin, H; Barsotti, R J; Rivera, A J; Martyn, D A; Clemmens, E

    2004-09-01

    In striated muscle thin filament activation is initiated by Ca(2+) binding to troponin C and augmented by strong myosin binding to actin (cross-bridge formation). Several lines of evidence have led us to hypothesize that thin filament properties may limit the level and rate of force development in cardiac muscle at all levels of Ca(2+) activation. As a test of this hypothesis we varied the cross-bridge contribution to thin filament activation by substituting 2 deoxy-ATP (dATP; a strong cross-bridge augmenter) for ATP as the contractile substrate and compared steady-state force and stiffness, and the rate of force redevelopment (k(tr)) in demembranated rat cardiac trabeculae as [Ca(2+)] was varied. We also tested whether thin filament dynamics limits force development kinetics during maximal Ca(2+) activation by comparing the rate of force development (k(Ca)) after a step increase in [Ca(2+)] with photorelease of Ca(2+) from NP-EGTA to maximal k(tr), where Ca(2+) binding to thin filaments should be in (near) equilibrium during force redevelopment. dATP enhanced steady-state force and stiffness at all levels of Ca(2+) activation. At similar submaximal levels of steady-state force there was no increase in k(tr) with dATP, but k(tr) was enhanced at higher Ca(2+) concentrations, resulting in an extension (not elevation) of the k(tr)-force relationship. Interestingly, we found that maximal k(tr) was faster than k(Ca), and that dATP increased both by a similar amount. Our data suggest the dynamics of Ca(2+)-mediated thin filament activation limits the rate that force develops in rat cardiac muscle, even at saturating levels of Ca(2+).

  18. Regulating emotions uniquely modifies reaction time, rate of force production, and accuracy of a goal-directed motor action.

    Science.gov (United States)

    Beatty, Garrett F; Fawver, Bradley; Hancock, Gabriella M; Janelle, Christopher M

    2014-02-01

    We investigated how emotion regulation (ER) strategies influence the execution of a memory guided, ballistic pinch grip. Participants (N=33) employed ER strategies (expressive suppression, emotional expression, and attentional deployment) while viewing emotional stimuli (IAPS images). Upon stimulus offset, participants produced a targeted pinch force aimed at 10% of their maximum voluntary contraction. Performance measures included reaction time (RT), rate of force production, and performance accuracy. As hypothesized, attentional deployment resulted in the slowest RT, largest rate of force production, and poorest performance accuracy. In contrast, expressive suppression reduced the rate of force production and increased performance accuracy relative to emotional expression and attentional deployment. Findings provide evidence that emotion regulation strategies uniquely influence human movement. Future work should further delineate the interacting role that emotion regulation strategies have in modulating both affective experience and motor performance.

  19. Mixing state of aerosols over the Indo-Gangetic Plain: Radiative forcing and heating rate

    Science.gov (United States)

    Srivastava, R.; Ramachandran, S.

    2012-12-01

    ratio is calculated from the geometry of core-shell particles, which depends on the mass and density of the core and shell. The size distribution parameters and refractive indices of different aerosol species are taken from OPAC database [3]. Different fractions of black carbon, water soluble and mineral dust aerosols involved in core-shell mixing emerge as the most probable mixing states over the IGP. Aerosol forcing for external mixing shows higher deviations from those for probable mixing cases during winter and pre-monsoon. The heating rate over Kanpur and Gandhi College in the lower troposphere is similar during pre-monsoon (March-May) ( 0.75 K day^{-1}) and monsoon (June-September) ( 0.5 K day^{-1}), while differences occur in other seasons [4]. Aerosol heating rate profiles exhibit primary and secondary peaks over the IGP and exhibit seasonal variations. Details on the calculations of aerosol mixing states over IGP, the impact of aerosol mixing state on aerosol forcing and heating rate will be discussed. References: [1] Intergovernmental panel on climate change (2007), Solomon S. et al. (eds.), Cambridge Univ. Press, NewYork. [2] Holben B. N., et al. (2001), J. Geophys. Res., 106(D11), 12067-12097. [3] Hess M., P. Koepke, I. Schult (1998), Bull. Am. Meteorol. Soc., 79, 831-844. [4] Srivastava R., S. Ramachandran (2012), Q. J. R. Meteorol. Soc., 138, doi:10.1002/qj.1958.

  20. Stress fields of the overriding plate at convergent margins and beneath active volcanic arcs.

    Science.gov (United States)

    Apperson, K D

    1991-11-01

    Tectonic stress fields in the overriding plate at convergent plate margins are complex and vary on local to regional scales. Volcanic arcs are a common element of overriding plates. Stress fields in the volcanic arc region are related to deformation generated by subduction and to magma generation and ascent processes. Analysis of moment tensors of shallow and intermediate depth earthquakes in volcanic arcs indicates that the seismic strain field in the arc region of many convergent margins is subhorizontal extension oriented nearly perpendicular to the arc. A process capable of generating such a globally consistent strain field is induced asthenospheric corner flow below the arc region.

  1. Force response of the fingertip pulp to repeated compression--effects of loading rate, loading angle and anthropometry.

    Science.gov (United States)

    Serina, E R; Mote, C D; Rempel, D

    1997-10-01

    Repeated loading of the fingertips has been postulated to contribute to tendon and nerve disorders at the wrist during activities associated with prolonged fingertip loading such as typing. To fully understand the pathomechanics of these soft tissue disorders, the role of the fingertip pulp in attenuating the applied dynamic forces must be known. An experiment was conducted to characterize the response of the in vivo fingertip pulp under repeated, dynamic, compressive loadings, to identify factors that influence pulp dynamics, and to better understand the force modulation by the pulp. Twenty subjects tapped repeatedly on a flat plate with their left index finger, while the contact force and pulp displacement were measured simultaneously. Tapping trials were conducted at three fingertip contact angles from the horizontal plane (0 degree, 45 degrees, and 90 degrees) and five tapping rates (0.25, 0.5, 1, 2, and 3 Hz). The fingertip pulp responds as a viscoelastic material, exhibiting rate-dependence, hysteresis, and a nonlinear force-displacement relationship. The pulp was relatively compliant at forces less than 1 N, but stiffened rapidly with displacement at higher forces for all loading conditions. This suggests that high-frequency forces of a small magnitude (< 1 N) are attenuated by the nonlinearly stiffening pulp while these forces of larger magnitude are transmitted to the bone. Pulp response was significantly influenced by the angle of loading. Fingertip dimensions, gender, and subject age had little to no influence on pulp parameters.

  2. RESISTANCE TRAINING FOR EXPLOSIVE AND MAXIMAL STRENGTH: EFFECTS ON EARLY AND LATE RATE OF FORCE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Felipe B.D. Oliveira

    2013-09-01

    Full Text Available The aim of the present study was to verify whether strength training designed to improve explosive and maximal strength would influence rate of force development (RFD. Nine men participated in a 6-week knee extensors resistance training program and 9 matched subjects participated as controls. Throughout the training sessions, subjects were instructed to perform isometric knee extension as fast and forcefully as possible, achieving at least 90% maximal voluntary contraction as quickly as possible, hold it for 5 s, and relax. Fifteen seconds separated each repetition (6-10, and 2 min separated each set (3. Pre- and post-training measurements were maximal isometric knee extensor (MVC, RFD, and RFD relative to MVC (i.e., %MVC·s-1 in different time-epochs varying from 10 to 250 ms from the contraction onset. The MVC (Nm increased by 19% (275.8 ± 64.9 vs. 329.8 ± 60.4, p < 0.001 after training. In addition, RFD (Nm·s-1 increased by 22-28% at time epochs up to 20 ms from the contraction onset (0-10 ms = 1679. 1 ± 597.1 vs. 2159.2 ± 475.2, p < 0.001; 0-20 ms = 1958.79 ± 640.3 vs. 2398.4 ± 479.6, p < 0. 01, with no changes verified in later time epochs. However, no training effects on RFD were found for the training group when RFD was normalized to MVC. No changes were found in the control group. In conclusion, very early and late RFD responded differently to a short period of resistance training for explosive and maximal strength. This time-specific RFD adaptation highlight that resistance training programs should consider the specific neuromuscular demands of each sport

  3. Differentials in female labour force participation rates in Indonesia: reflection of economic needs and opportunities, culture or bad data?

    Science.gov (United States)

    Jones, G

    1986-12-01

    This study investigates regional differentials in female labor force participation rates by educational status in Indonesia, using data from the 1961, 1971, and 1980 censuses. Rates in the Javanese areas are always well above the Indonesian average; in mainly Sundanese West Java they are much lower than the average, and in South Sulawesi they are lower still. Kalimantan is the only region where there is no stability in rates over time, possibly due to the inaccessibility of much of its population for census-taking. When only urban areas are considered, the regional differentials do not alter very much. As in most of the world, participation rates for single women are higher than those of married women, and those for divorced and widowed women are higher still. Participation rates are lowest of all for women with a junior high school education, rise for those witha senior high school education; and rise sharply for those with a university or academy education. The provinces with the highest urban female labor force participation rates--Yogyakarta, Central Java, East Java, and Bali--are among the poorest provinces in Indonesia. Female labor force participation rates in Indonesia are much higher than in other Moslem countries. Geographic and socioeconomic differentials in female labor force participation rates in Indonesia are not an artifact of inconsistencies in the data, but can be related to 2 other sets of explanatory variables: 1) economic needs and opportunities and 2) cultural differences.

  4. Associations Between Rate of Force Development Metrics and Throwing Velocity in Elite Team Handball Players: a Short Research Report

    OpenAIRE

    Marques, Mário C.; Saavedra, Francisco J.; Abrantes, Catarina; Felipe J. Aidar

    2011-01-01

    Performance assessment has become an invaluable component of monitoring participant’s development in distinct sports, yet limited and contradictory data are available in trained subjects. The purpose of this study was to examine the relationship between ball throwing velocity during a 3-step running throw in elite team handball players and selected measures of rate of force development like force, power, velocity, and bar displacement during a concentric only bench press exercise in elite mal...

  5. The effect of strength training and short-term detraining on maximum force and the rate of force development of older men.

    Science.gov (United States)

    Lovell, Dale I; Cuneo, Ross; Gass, Greg C

    2010-06-01

    This study examined the effect of strength training (ST) and short-term detraining on maximum force and rate of force development (RFD) in previously sedentary, healthy older men. Twenty-four older men (70-80 years) were randomly assigned to a ST group (n = 12) and C group (control, n = 12). Training consisted of three sets of six to ten repetitions on an incline squat at 70-90% of one repetition maximum three times per week for 16 weeks followed by 4 weeks of detraining. Regional muscle mass was assessed before and after training by dual-energy X-ray absorptiometry. Training increased RFD, maximum bilateral isometric force, and force in 500 ms, upper leg muscle mass and strength above pre-training values (14, 25, 22, 7, 90%, respectively; P force and RFD of older men. However, older individuals may lose some neuromuscular performance after a period of short-term detraining and that resistance exercise should be performed on a regular basis to maintain training adaptations.

  6. 77 FR 65169 - Extension of Certain Timber Sale Contracts; Finding of Substantial Overriding Public Interest

    Science.gov (United States)

    2012-10-25

    ... increases competition for National Forest System timber sales, results in higher prices paid for such timber... hazardous fuels. On June 1, 2012, there were 98 National Forest System timber sales under contract in... Forest Service Extension of Certain Timber Sale Contracts; Finding of Substantial Overriding Public...

  7. Caffeine stabilizes Cdc25 independently of Rad3 in S chizosaccharomyces pombe contributing to checkpoint override

    Science.gov (United States)

    Alao, John P; Sjölander, Johanna J; Baar, Juliane; Özbaki-Yagan, Nejla; Kakoschky, Bianca; Sunnerhagen, Per

    2014-01-01

    Cdc25 is required for Cdc2 dephosphorylation and is thus essential for cell cycle progression. Checkpoint activation requires dual inhibition of Cdc25 and Cdc2 in a Rad3-dependent manner. Caffeine is believed to override activation of the replication and DNA damage checkpoints by inhibiting Rad3-related proteins in both S chizosaccharomyces pombe and mammalian cells. In this study, we have investigated the impact of caffeine on Cdc25 stability, cell cycle progression and checkpoint override. Caffeine induced Cdc25 accumulation in S . pombe independently of Rad3. Caffeine delayed cell cycle progression under normal conditions but advanced mitosis in cells treated with replication inhibitors and DNA-damaging agents. In the absence of Cdc25, caffeine inhibited cell cycle progression even in the presence of hydroxyurea or phleomycin. Caffeine induces Cdc25 accumulation in S . pombe by suppressing its degradation independently of Rad3. The induction of Cdc25 accumulation was not associated with accelerated progression through mitosis, but rather with delayed progression through cytokinesis. Caffeine-induced Cdc25 accumulation appears to underlie its ability to override cell cycle checkpoints. The impact of Cdc25 accumulation on cell cycle progression is attenuated by Srk1 and Mad2. Together our findings suggest that caffeine overrides checkpoint enforcement by inducing the inappropriate nuclear localization of Cdc25. PMID:24666325

  8. Aerosol Climatology at Pune, Western India: Implications to Direct Radiative Forcing and Heating Rates

    Science.gov (United States)

    Pandithurai, G.; Pinker, R. T.; Devara, P. C.; Raj, P. E.; Jayarao, Y.; Dani, K. K.; Maheskumar, R. S.; Sonbawne, S. M.; Saha, S. K.; Bhawar, R.; Shinde, U. P.

    2005-12-01

    Extensive aerosol observations were carried out at Indian Institute of Tropical Meteorology (IITM), Pune, an urban site in the western part of the country, using a Prede (Model POM-01L) sun/sky radiometer and a bi-static Argon ion lidar since December 2000 and October 1986, respectively. The sun/sky radiometer was operated daily at every 15 minute interval during day-time to derive column aerosol optical parameters such as aerosol optical depth (AOD), single scattering albedo (SSA), asymmetry parameter (ASY) while the lidar was operated weekly in the early-night period to derive vertical distributions of aerosol number density. The sun/sky radiance data collected during the above period have been analysed by using the radiative transfer model SkyRadPack version 3.0 (Nakajima et al. 1996) to retrieve AOD, SSA and ASY. AOD and SSA retrieved at 15-minutes interval were averaged to get monthly means. On every year from 2000 to 2005, monthly means of AOD show gradual increase of aerosol loading from December to April and Angstrom exponent decreases from March due to local as well as transported dust from African / Arabian regions through Arabian Sea. Monthly means of SSA show decrease from December to April and the wavelength dependence also indicate the abundance of dust from March to May. Lidar-derived vertical distributions yield minimum during the monsoon months, gradually builds up during the post-monsoon and winter months, and finally peaks during the pre-monsoon months in every year (Devara et al., 2002). The aerosol climatology of optical/radiative parameters and their vertical distribution are used for estimating aerosol radiative forcing (ARF) and atmospheric heating rates by using a discrete-ordinate radiative transfer model (Ricchiazzi et al., 1998, Pandithurai et al. 2004). Details of the experimental methods, data, results of aerosol climatology and implications to radiative forcing and associated heating rates will be presented. References Devara, P

  9. Forced distribution rating systems: when does "rank and yank" lead to adverse impact?

    Science.gov (United States)

    Giumetti, Gary W; Schroeder, Amber N; Switzer, Fred S

    2015-01-01

    Despite widespread use of forced distribution rating systems (FDRSs), the potential for this performance appraisal method to lead to adverse impact (AI) in a layoff context has yet to be examined empirically. Thus, the current study uses a Monte Carlo simulation to examine the likelihood of encountering AI violations when an FDRS is used in the context of layoffs. The primary research questions included an examination of how AI violations change depending on the definition of the employment action (i.e., retention vs. layoff), the length of the repeated layoffs, and whether or not laid off employees are replaced each year. The current study also examined the impact of the size of the organization, the percentage of the workforce laid off, and the type of AI calculation method used on the likelihood of AI violations. Results suggest that defining the employment action as layoffs (rather than as retentions) may result in a greater likelihood of AI violations, and AI violations are likely to peak in the 1st year of use. Further, replacing laid off employees may result in higher levels of AI over time as compared with not replacing layoffs. Additionally, the greatest risk for AI occurs when the organization size is large (i.e., N = 10,000) and when certain AI calculation methods are used. Results are discussed in terms of their practical and legal implications for organizations.

  10. Effects of fast-velocity eccentric resistance training on early and late rate of force development.

    Science.gov (United States)

    Oliveira, Anderson Souza; Corvino, Rogério Bulhões; Caputo, Fabrizio; Aagaard, Per; Denadai, Benedito Sérgio

    2016-01-01

    This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (100 ms) of rising torque. Twenty healthy men were assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180 °s-1. Maximal isometric knee extensor torque (MVC) and incremental RFD in successive 50 ms time-windows from the onset contraction were analysed in absolute terms (RFDINC) or when normalised relative to MVC (RFDREL). After eight weeks, TG demonstrated increases in MVC (28%), RFDINC (0-50 ms: 30%; 50-100 ms: 31%) and RFDREL (0-50 ms: 29%; 50-100 ms: 32%). Moreover, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFDINC and RFDREL obtained at the early phase of rising joint torque.

  11. The rate of force generation by the myocardium is not influenced by afterload

    Directory of Open Access Journals (Sweden)

    Fioretto J.R.

    1997-01-01

    Full Text Available The influence of afterload on the rate of force generation by the myocardium was investigated using two types of preparations: the in situ dog heart (dP/dt and isolated papillary muscle of rats (dT/dt. Thirteen anesthetized, mechanically ventilated and thoracotomized dogs were submitted to pharmacological autonomic blockade (3.0 mg/kg oxprenolol plus 0.5 mg/kg atropine. A reservoir connected to the left atrium permitted the control of left ventricular end-diastolic pressure (LVEDP. A mechanical constriction of the descending thoracic aorta allowed to increase the systolic pressure in two steps of 20 mmHg (conditions H1 and H2 above control values (condition C. After arterial pressure elevations (systolic pressure C: 119 ± 8.1; H1: 142 ± 7.9; H2 166 ± 7.7 mmHg; P<0.01, there were no significant differences in heart rate (C: 125 ± 13.9; H1: 125 ± 13.5; H2: 123 ± 14.1 bpm; P>0.05 or LVEDP (C: 6.2 ± 2.48; H1: 6.3 ± 2.43; H2: 6.1 ± 2.51 mmHg; P>0.05. The values of dP/dt did not change after each elevation of arterial pressure (C: 3,068 ± 1,057; H1: 3,112 ± 996; H2: 3,086 ± 980 mmHg/s; P>0.05. In isolated rat papillary muscle, an afterload corresponding to 50% and 75% of the maximal developed tension did not alter the values of the maximum rate of tension development (100%: 78 ± 13; 75%: 80 ± 13; 50%: 79 ± 11 g mm-2 s-1, P>0.05. The results show that the rise in afterload per se does not cause changes in dP/dt or dT/dt

  12. Increased rate of force development and neuromuscular activity after high-load resistance training in patients undergoing dialysis

    DEFF Research Database (Denmark)

    Molsted, Stig; Andersen, Jesper L.; Eidemak, Inge

    2013-01-01

    AimThe aim of this study was to investigate the effects of high-load resistance training on the rate of force development and neuromuscular function in patients undergoing dialysis. MethodsTwenty-nine patients were tested before and after 16 weeks of resistance training. The rate of force...... development was tested using the Good Strength dynamometer chair. Muscle strength and neuromuscular function in the m. Vastus lateralis was estimated using electromyography in a one repetition maximum test during dynamic knee extension and during a 20s isometric knee extension with 50% of the one repetition...

  13. In vivo forces generated by finger flexor muscles do not depend on the rate of fingertip loading during an isometric task.

    Science.gov (United States)

    Kursa, Katarzyna; Diao, Edward; Lattanza, Lisa; Rempel, David

    2005-11-01

    Risk factors for activity-related tendon disorders of the hand include applied force, duration, and rate of loading. Understanding the relationship between external loading conditions and internal tendon forces can elucidate their role in injury and rehabilitation. The goal of this investigation is to determine whether the rate of force applied at the fingertip affects in vivo forces in the flexor digitorum profundus (FDP) tendon and the flexor digitorum superficialis (FDS) tendon during an isometric task. Tendon forces, recorded with buckle force transducers, and fingertip forces were simultaneously measured during open carpal tunnel surgery as subjects (N=15) increased their fingertip force from 0 to 15N in 1, 3, and 10s. The rates of 1.5, 5, and 15N/s did not significantly affect FDP or FDS tendon to fingertip force ratios. For the same applied fingertip force, the FDP tendon generated more force than the FDS. The mean FDP to fingertip ratio was 2.4+/-0.7 while the FDS to tip ratio averaged 1.5+/-1.0 (pfinger muscles in order to stabilize the finger and control joint torques at the force rates studied. Therefore, for this task, no additional increase in muscle force was observed at higher rates. These findings suggest that for high precision, isometric pinch maneuvers under static finger conditions, tendon forces are independent of loading rate.

  14. Associations between rate of force development metrics and throwing velocity in elite team handball players: a short research report.

    Science.gov (United States)

    Marques, Mário C; Saavedra, Francisco J; Abrantes, Catarina; Aidar, Felipe J

    2011-09-01

    Performance assessment has become an invaluable component of monitoring participant's development in distinct sports, yet limited and contradictory data are available in trained subjects. The purpose of this study was to examine the relationship between ball throwing velocity during a 3-step running throw in elite team handball players and selected measures of rate of force development like force, power, velocity, and bar displacement during a concentric only bench press exercise in elite male handball players. Fitteen elite senior male team handball players volunteered to participate. Each volunteer had power and bar velocity measured during a concentric only bench press test with 25, 35, and 45 kg as well as having one-repetition maximum strength determined. Ball throwing velocity was evaluated with a standard 3-step running throw using a radar gun. The results of this study indicated significant associations between ball velocity and time at maximum rate of force development (0, 66; prate of force development at peak force (0,56; prate of force development with light loads. A training regimen designed to improve ball-throwing velocity in elite male team handball players should emphasize bench press movement using light loads.

  15. Dynamic Patterns of Forces and Loading Rate in Runners with Unilateral Plantar Fasciitis: A Cross-Sectional Study.

    Directory of Open Access Journals (Sweden)

    Ana Paula Ribeiro

    Full Text Available The etiology of plantar fasciitis (PF has been related to several risk factors, but the magnitude of the plantar load is the most commonly described factor. Although PF is the third most-common injury in runners, only two studies have investigated this factor in runners, and their results are still inconclusive regarding the injury stage.Analyze and compare the plantar loads and vertical loading rate during running of runners in the acute stage of PF to those in the chronic stage of the injury in relation to healthy runners.Forty-five runners with unilateral PF (30 acute and 15 chronic and 30 healthy control runners were evaluated while running at 12 km/h for 40 meters wearing standardized running shoes and Pedar-X insoles. The contact area and time, maximum force, and force-time integral over the rearfoot, midfoot, and forefoot were recorded and the loading rate (20-80% of the first vertical peak was calculated. Groups were compared by ANOVAs (p<0.05.Maximum force and force-time integral over the rearfoot and the loading rate was higher in runners with PF (acute and chronic compared with controls (p<0.01. Runners with PF in the acute stage showed lower loading rate and maximum force over the rearfoot compared to runners in the chronic stage (p<0.01.Runners with PF showed different dynamic patterns of plantar loads during running over the rearfoot area depending on the injury stage (acute or chronic. In the acute stage of PF, runners presented lower loading rate and forces over the rearfoot, possibly due to dynamic mechanisms related to pain protection of the calcaneal area.

  16. Dissociated time course recovery between rate of force development and peak torque after eccentric exercise.

    Science.gov (United States)

    Molina, Renato; Denadai, Benedito S

    2012-05-01

    This study investigated the association between isokinetic peak torque (PT) of quadriceps and the corresponding peak rate of force development (peak RFD) during the recovery of eccentric exercise. Twelve untrained men (aged 21·7 ± 2·3 year) performed 100 maximal eccentric contractions for knee extensors (10 sets of 10 repetitions with a 2-min rest between each set) on isokinetic dynamometer. PT and peak RFD accessed by maximal isokinetic knee concentric contractions at 60° s(-1) were obtained before (baseline) and at 24 and 48 h after eccentric exercise. Indirect markers of muscle damage included delayed onset of muscle soreness (DOMS) and plasma creatine kinase (CK) activity. The eccentric exercise resulted in elevated DOMS and CK compared with baseline values. At 24 h, PT (-15·3%, P = 0·002) and peak RFD (-13·1%, P = 0·03) decreased significantly. At 48 h, PT (-7·9%, P = 0·002) was still decreased but peak RFD have returned to baseline values. Positive correlation was found between PT and peak RFD at baseline (r = 0·62, P = 0·02), 24 h (r = 0·99, P = 0·0001) and 48 h (r = 0·68, P = 0·01) after eccentric exercise. The magnitude of changes (%) in PT and peak RFD from baseline to 24 h (r = 0·68, P = 0·01) and from 24 to 48 h (r = 0·68, P = 0·01) were significantly correlated. It can be concluded that the muscle damage induced by the eccentric exercise affects differently the time course of PT and peak RFD recovery during isokinetic concentric contraction at 60° s(-1). During the recovery from exercise-induced muscle damage, PT and peak RFD are determined but not fully defined by shared putative physiological mechanisms. © 2011 The Authors. Clinical Physiology and Functional Imaging © 2011 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

  17. Agglomeration rate and action forces between atomized particles of agglomerator and inhaled-particles from coal combustion

    Institute of Scientific and Technical Information of China (English)

    WEI Feng; ZHANG Jun-ying; ZHENG Chu-guang

    2005-01-01

    In order to remove efficiently haled-particles emissions from coal combustions, a new way was used to put forward the process of agglomeration and the atomization was produced by the nozzle and then sprayed into the flue before precipitation devices of power station boiler in order to make inhaled-particles agglomerate into bigger particles, which can be easily removed but not change existing running conditions of boiler. According to this idea, a model is set up to study agglomeration rate and effect forces between fly ash inhaledparticles and atomized agglomerator particles. The developed agglomeration rate was expressed by relative particle number decreasing speed per unit volume. The result showed that viscosity force and flow resistance force give main influences on agglomeration effect of inhaled particles, while springiness force and gravity have little effect on agglomeration effect of theirs. Factors influencing the agglomeration rate and effect forces are studied, including agglomerator concentration, agglomerator flux and agglomerator density,atomized-particles diameters and inhaled-particles diameter and so on.

  18. ROV: improving remotely operated vehicle (ROV) intervention capabilities for blowout preventer override systems

    Energy Technology Data Exchange (ETDEWEB)

    Lazar, Stephen [Christopher S. Mancini, Tomball, TX (United States)

    2012-07-01

    Events during 2010 have focused attention on increased ROV/BOP Intervention capabilities and standardization of BOP/ROV interfaces in the oil and gas offshore industry. Currently no enforced set standards for ROV intervention panels or manifold types for use on BOP Override systems are specified. The industry offers multiple configurations at present. This abstract will discuss the advantages and disadvantages of the various configurations in existence, trending toward suggested industry standards taking shape as requirements in the near term. Standards for the offshore industry or a set specification must be made to increase safety and functionality of BOP control systems. To date, ROV override capabilities have been added to existing engineered BOP systems. BOP designed closing times were not a critical consideration, only that the access was there to allow for ROV override. Increased ROV flow and pressure capabilities: no current minimum flow requirements for Emergency BOP Override pumps are established. Based on stack valving and configuration, a minimum, 7 gpm may be required to shift valving fully to allow BOP operator function. IADC/API minimum requirements may be proposed at 10 gpm at 3000psi. Based on shear pressures exceeding 3000psi, pressures of 5000psi should be considered. Current intervention skids/pump capabilities will be required if ROVs must achieve API 16D BOP minimum closing times. Remote or isolated accumulation for increased intervention capabilities offers possibilities when ANY ROV of opportunity can trigger a function (such as small inspection type ROVs). Increased volumes will be required. This is critical in functioning stack rams with an ROV of opportunity to achieve API 16D closing times. We now understand that higher flows and pressures are required along with standardization of stab types. Current recommendations: API 17H Hi-Flow manifolds should be added to essential ROV overrides. ROV skids will have a minimum requirement of 10gpm

  19. Validity and reproducibility of crutch force and heart rate measurements to assess energy expenditure of paraplegic gait

    NARCIS (Netherlands)

    IJzerman, Maarten J.; Baardman, Gert; Hof, van 't Martin A.; Boom, Herman B.K.; Hermens, Hermie J.; Veltink, Peter H.

    1999-01-01

    Objective: To determine the validity and reproducibility of heart rate (HR) and crutch force measurements to estimate energy expenditure during paraplegic walking. Usefulness of these outcome measures in comparative trials was assessed in terms of responsiveness. Design: Cross-sectional validity was

  20. SMB myosin heavy chain knockout enhances tonic contraction and reduces the rate of force generation in ileum and stomach antrum.

    Science.gov (United States)

    Huang, Qian; Babu, Gopal J; Periasamy, Muthu; Eddinger, Thomas J

    2013-01-15

    The role of SMA and SMB smooth muscle myosin heavy chain (MHC) isoforms in tonic and phasic contractions was studied in phasic (longitudinal ileum and stomach circular antrum) and tonic (stomach circular fundus) smooth muscle tissues of SMB knockout mice. Knocking out the SMB MHC gene eliminated SMB MHC protein expression and resulted in upregulation of the SMA MHC protein without altering the total MHC protein level. Switching from SMB to SMA MHC protein expression decreased the rate of the force transient and increased the sustained tonic force in SMB((-/-)) ileum and antrum with high potassium (KPSS) but not with carbachol (CCh) stimulation. The increased tonic contraction under the depolarized condition was not through changes in second messenger signaling pathways (PKC/CPI-17 or Rho/ROCK signaling pathway) or LC(20) phosphorylation. Biochemical analyses showed that the expression of contractile regulatory proteins (MLCK, MLCP, PKCδ, and CPI-17) did not change significantly in tissues tested except for PKCα protein expression being significantly decreased in the SMB((-/-)) antrum. However, specifically activating PKCα with phorbol dibutyrate (PDBu) was not significantly different in knockout and wild-type tissues, with total force being a fraction of the force generation with KPSS or CCh stimulation in SMB((-/-)) ileum and antrum. Taken together, these data show removing the SMB MHC protein expression with a compensatory increase in the SMA MHC protein results in enhanced sustained KPSS-induced tonic contraction with a reduced rate of force generation in these phasic tissues.

  1. Improvements in rate of development and magnitude of force with intense auditory stimuli in patients with Parkinson's disease.

    Science.gov (United States)

    Anzak, Anam; Tan, Huiling; Pogosyan, Alek; Djamshidian, Atbin; Ling, Helen; Lees, Andrew; Brown, Peter

    2011-07-01

    Patients with Parkinson's disease can show brief but dramatic normalization of motor activity in highly arousing situations, a phenomenon often termed paradoxical kinesis. We sought to mimic this in a controlled experimental environment. Nine patients with Parkinson's disease and nine age-matched healthy controls were asked to grip a force dynamometer as quickly and strongly as possible in response to a visual cue. A loud (96 dB) auditory stimulus was delivered at the same time as the visual cue in ~50% of randomly selected trials. In patients with Parkinson's disease, the experiment was conducted after overnight withdrawal of antiparkinsonian drugs and again 1 h after patients had taken their usual morning medication. Patients showed improvements in the peak rate of force development and the magnitude of force developed when loud auditory stimuli accompanied visual cues. Equally, they showed improvements in the times taken to reach the peak rate of force development and their maximal force. The paradoxical facilitatory effect of sound was similar whether patients were off or on their usual antiparkinsonian medication, and could be reproduced in age-matched healthy controls. We conclude that motor improvement induced by loud auditory stimuli in Parkinson's disease is related to a physiological phenomenon which survives both with and after withdrawal of antiparkinsonian medication. The potential independence of the mediating pathways from the dopaminergic system provides impetus for further investigation as it may yield a novel nondopaminergic target for therapeutic manipulation in Parkinson's disease.

  2. SU-E-T-599: Patient Safety Enhancements Through a Study of R&V System Override Data

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, K; Vimolchalao, S [University of Washington, Seattle, WA (United States)

    2015-06-15

    Purpose: Record and verify (R&V) software systems include safety checks that compare actual machine parameters with prescribed values for a patient’s treatment, such as treatment couch position, linac, energy, and MUs. The therapist is warned of a mismatch with a pop-up and prompted to approve an override in order to continue without changes. Override approval is often legitimate, but the pop-up can also genuinely indicate a problem that would Result in the wrong treatment. When there are numerous pop-up warnings, human nature leads us to approve any override without careful reading, undermining the effectiveness of the safety mechanism. Methods: Override data was collected from our R&V system for all patients treated between October 8 and 29, 2012, on four linacs and entered into a spreadsheet. Additional data collected included treatment technique, disease site, immobilization, time, linac, and whether localization images were obtained. Data were analyzed using spreadsheet tools to reveal trends, patterns and associations that might suggest appropriate process changes that could decrease the total number of overrides. Results: 76 out of 113 patients had overrides. Out of the 944 treatments, 599 override items were generated. The majority were due to couch positions. 74 of the 84 overrides on a linac equipped with a 6D couch were due to the use of the rotational corrections and the fact that the 6D couch control does not communicate with the R&V system; translations required to rotate the couch appear to the R&V system as translations outside the tolerance range. Conclusion: Many findings were interesting but did not suggest a process change. Proposed process changes include creating site-specific instead of just technique-specific tolerance tables for couch shifts. Proposed improvements to the vendor are to facilitate direct communication between the 6D couch and the R&V system to eliminate those override warnings related to lack of communication.

  3. Ultrasound biomicroscopy confirmation of corneal overriding due to improper suturing of full-thickness corneal laceration

    Directory of Open Access Journals (Sweden)

    Murat Kucukevcilioglu

    2014-12-01

    Full Text Available We herein present a case with corneal overriding due to improper suturing of a full-thickness corneal laceration. There was a 2.5-mm difference between horizontal and vertical white-to-white measurements in the cornea. However, slit lamp examination failed to demonstrate the exact architecture of the laceration. Ultrasound biomicroscopy defined the wound edges thoroughly and confirmed the presence of corneal overriding. Six weeks after suture enhancement, the abnormal oval appearance of the cornea was absent and correct apposition of the corneal edges was seen on ultrasound biomicroscopy. Ultrasound biomicroscopy can be used in preoperative surgical planning of cases with complicated corneal lacerations. It can be used to adjust and enhance wound architecture in eyes with penetrating injury.

  4. Do habits always override intentions? Pitting unhealthy snacking habits against snack-avoidance intentions

    OpenAIRE

    Gardner, Benjamin; Corbridge, Sharon; McGowan, Laura

    2015-01-01

    Background Habit is defined as a process whereby an impulse towards behaviour is automatically initiated upon encountering a setting in which the behaviour has been performed in the past. A central tenet of habit theory is that habit overrides intentional tendencies in directing behaviour, such that as habit strength increases, intention becomes less predictive of behaviour. Yet, evidence of this effect has been methodologically limited by modelling the impact of positively-correlated habits ...

  5. Seismic evidence for deep fluid circulation in the overriding plate of subduction zones

    Science.gov (United States)

    Tauzin, B.; Reynard, B.; Bodin, T.; Perrillat, J. P.; Debayle, E.

    2015-12-01

    In subduction zones, non-volcanic tremors are associated with fluid circulations (Obara, 2002). Their sources are often located on the interplate boundary (Rogers and Dragert, 2003; Shelly et al, 2006; La Rocca, 2009), consistent with fluids released by the dehydration of subducted plates (Hacker et al., 2003). Reports of tremors in the overriding continental crust of several subduction zones in the world (Kao et al., 2005; Payero et al., 2008; Ide, 2012) suggest fluid circulation at shallower depths but potential fluid paths are poorly documented. Here we obtained seismic observations from receiver functions that evidence the close association between the shallow tremor zone, electrical conductivity, and tectonic features of the Cascadia overriding plate. A seismic discontinuity near 15 km depth in the crust of the overriding North American plate is attributed to the Conrad discontinuity. This interface is segmented, and its interruption is spatially correlated with conductive regions and shallow swarms of seismicity and non-volcanic tremors. These observations suggest that shallow fluid circulation, tremors and seismicity are controlled by fault zones limiting blocks of accreted terranes in the overriding plate (Brudzinski and Allen, 2007). These zones constitute fluid "escape" routes that may contribute unloading fluid pressure on the megathrust. Obara, K. (2002). Science, 296, 1679-1681. Rogers, G., & Dragert, H. (2003). Science, 300, 1942-1943. Shelly, D. R., et al. (2006). Nature, 442, 188-191. La Rocca, M., et al. (2009). Science, 323, 620-623. Kao, H., et al. (2005). Nature, 436, 841-844. Payero, J. S., et al. (2008). Geophysical Research Letters, 35. Ide, S. (2012). Journal of Geophysical Research: Solid Earth, 117. Brudzinski, M. R., & Allen, R. M. (2007). Geology, 35, 907-910.

  6. Confirmation of linear system theory prediction: Rate of change of Herrnstein's κ as a function of response-force requirement

    Science.gov (United States)

    McDowell, J. J; Wood, Helena M.

    1985-01-01

    Four human subjects worked on all combinations of five variable-interval schedules and five reinforcer magnitudes (¢/reinforcer) in each of two phases of the experiment. In one phase the force requirement on the operandum was low (1 or 11 N) and in the other it was high (25 or 146 N). Estimates of Herrnstein's κ were obtained at each reinforcer magnitude. The results were: (1) response rate was more sensitive to changes in reinforcement rate at the high than at the low force requirement, (2) κ increased from the beginning to the end of the magnitude range for all subjects at both force requirements, (3) the reciprocal of κ was a linear function of the reciprocal of reinforcer magnitude for seven of the eight data sets, and (4) the rate of change of κ was greater at the high than at the low force requirement by an order of magnitude or more. The second and third findings confirm predictions made by linear system theory, and replicate the results of an earlier experiment (McDowell & Wood, 1984). The fourth finding confirms a further prediction of the theory and supports the theory's interpretation of conflicting data on the constancy of Herrnstein's κ. PMID:16812408

  7. Explosive resistance training increases rate of force development in ankle dorsiflexors and gait function in adults with cerebral palsy

    DEFF Research Database (Denmark)

    Kirk, Henrik; Geertsen, Svend Sparre; Lorentzen, Jakob

    2016-01-01

    Alterations in passive elastic properties of muscles and reduced ability to quickly generate muscle force contribute to impaired gait function in adults with cerebral palsy (CP). Here, we investigated if 12 weeks of progressive and explosive resistance training (PRT) increases rate of force...... dorsiflexion, plantarflexion, leg press, hamstring curls, abdominal curls and back extension 3 days/week for 12 weeks, with 3 sets per exercise and progressing during the training period from 12-6 RM. RFDdf, 3-D gait analysis, functional performance and ankle joint passive- and reflex-mediated muscle stiffness...

  8. Rating forces grip and driving and accelerations of the car with drive different configuration

    Directory of Open Access Journals (Sweden)

    Kowalski Mariusz

    2015-12-01

    Full Text Available The paper shows a typical drive systems used in today's vehicles, mainly cars. Approximated scheme of the formation of the driving force of the vehicle and the necessary mathematical relations for the calculation. For example, a typical passenger car BMW 320 was analyzed and calculations obtained a driving force, of adhesion and acceleration. The calculations were performed for the drive system, the classical (i.e. the rear axle of the vehicle for front-wheel drive and four-wheel drive (4×4. Virtually assumed that to the above mentioned vehicle it is possible buildings of each of said system. These are shown graphically in diagrams bearing a distribution of the forces acting on the substrate and the reactions - the data necessary for the calculations. The resulting calculation is graphically shown in the diagrams, in which is illustrated a change value of the resulting adhesive strength, and the acceleration depending on the drive type vehicle.

  9. Effect of axial force on the performance of micromachined vibratory rate gyroscopes.

    Science.gov (United States)

    Hou, Zhanqiang; Xiao, Dingbang; Wu, Xuezhong; Dong, Peitao; Chen, Zhihua; Niu, Zhengyi; Zhang, Xu

    2011-01-01

    It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F) beam and the other one was suspended with a clamped-clamped (C-C) beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF) due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.

  10. Effect of Axial Force on the Performance of Micromachined Vibratory Rate Gyroscopes

    Directory of Open Access Journals (Sweden)

    Zhengyi Niu

    2010-12-01

    Full Text Available It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F beam and the other one was suspended with a clamped-clamped (C-C beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.

  11. Effects of Rate of Movement on Effective Maximal Force Generated by Elbow Extensors.

    Science.gov (United States)

    Updyke, Wynn F.; And Others

    This study investigated the effects of the velocity of muscular contraction on the effective force (torque) exerted by forty 18- to 21-year-old males. The dynomemeter lever arm, the fulcrum of which was aligned with the axis of elbow rotation, allowed extension and flexion for the subjects. All subjects were tested at three velocities (.10, .20,…

  12. Military milk: breastfeeding rates among Australian Defence Force women who return to military service following maternity leave.

    Science.gov (United States)

    Stewart, Kelley

    2015-02-01

    The breastfeeding behaviors among Australian Defence Force women have not previously been examined. Studies have shown that breastfeeding prevalence and duration are affected by maternity leave entitlements and returning to work. This study aimed to benchmark breastfeeding initiation, prevalence, and duration among a cohort of Australian Defence Force women and to compare these findings against Australian population norms. A cross-sectional survey was conducted via email in 2008 for Australian Defence Force women who had taken maternity leave in the Australian financial year of 2006/2007. Analysis of breastfeeding indicators was undertaken. Ninety-eight percent of Australian Defence Force women in this cohort initiated breastfeeding and breastfed for a median duration of 8 months, returning to work when the mean age of the child was 8.4 months. Breastfeeding prevalence did not meet 2003 Australian National Health and Medical Research Council targets by 6 months postpartum but compared favorably to the Australian population norms. Sixty-six percent of the respondents returned to work full-time, with a median breastfeeding duration of 7 months. Women who returned to work part-time had a longer median duration of 10 months. Breastfeeding rates among this cohort of Australian Defence Force women compare favorably with the general Australian population until 9 months, coinciding with returning to work after a period of maternity leave. The results support recent Australian population studies on breastfeeding and employment. © The Author(s) 2014.

  13. Modelling the effect of rail dampers on wheel-rail interaction forces and rail roughness growth rates

    Science.gov (United States)

    Croft, B. E.; Jones, C. J. C.; Thompson, D. J.

    2009-06-01

    Trains generate rolling noise because of the roughness of the wheel and rail running surfaces. Special acoustic grinding programmes have been introduced on some railways specifically to control rolling noise. Rail dampers are also used to reduce rolling noise; this paper studies rail damping as a possible mechanism to slow the rate of development of roughness on the surface of rails. This would reduce noise further over time or reduce the required frequency of grinding. High roughness growth on the rail occurs in situations with stiff vertical structural dynamics of the track. In particular the antiresonance above a sleeper at the pinned-pinned frequency has been identified as a wavelength fixing mechanism for short pitch corrugation. Rail dampers change the dynamic response of the rail, shifting the pinned-pinned frequency and smoothing the track receptance. Here, a simple time-stepping model is applied to calculate the interaction forces between wheel and rail for a track with and without rail dampers. The calculations show that rail dampers reduce dynamic interaction forces and shift the force spectrum to longer wavelengths. The interaction forces are used as input to an abrasive wear model to predict the roughness growth rate and the change in roughness after many wheel passages. Track without rail dampers is predicted to develop corrugation at the wavelength corresponding to the pinned-pinned frequency. With rail dampers the corrugation growth is reduced and shifted to a longer wavelength where its significance is diminished.

  14. Grip force and heart rate responses to manual carrying tasks: effects of material, weight, and base area of the container.

    Science.gov (United States)

    Lee, Tzu-Hsien; Tseng, Chia-Yun

    2014-01-01

    This study recruited 16 industrial workers to examine the effects of material, weight, and base area of container on reduction of grip force (ΔGF) and heart rate for a 100-m manual carrying task. This study examined 2 carrying materials (iron and water), 4 carrying weights (4.4, 8.9, 13.3, 17.8 kg), and 2 base areas of container (24 × 24 cm, 35 × 24 cm). This study showed that carrying water significantly increased ΔGF and heart rate as compared with carrying iron. Also, ΔGF and heart rate significantly increased with carrying weight and base area of container. The effects of base area of container on ΔGF and heart rate were greater in carrying water condition than in carrying iron condition. The maximum dynamic effect of water on ΔGF and heart rate occurred when water occupied ~60%-80% of full volume of the container.

  15. Forced Unbinding of Individual Urea – Aminotriazine Supramolecular Polymers by Atomic Force Microscopy: A Closer Look at the Potential Energy Landscape and Binding Lengths at Fixed Loading Rates

    NARCIS (Netherlands)

    Embrechts, A.; Schönherr, Holger; Vancso, Gyula J.

    2012-01-01

    Atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) was used to study the forced unbinding of quadruple self-complementary hydrogen-bonded urea–aminotriazine (UAT) complexes in hexadecane (HD). To elucidate the bond strength of individual linkages the unbinding forces of UAT

  16. Sum-rate analysis of spectrum sharing spatial multiplexing MIMO systems with zero-forcing and multiuser diversity

    KAUST Repository

    Yang, Liang

    2013-06-01

    This paper considers a multiuser spectrum sharing (SS) multiple-input multiple-output (MIMO) system with zero-forcing (ZF) operating in a Rayleigh fading environment. We provide an asymptotic sum-rate analysis to investigate the effects of different parameters on the multiuser diversity gain. For a ZF SS spatial multiplexing system with scheduling, the asymptotic sum-rate scales like Nt log2(Q(Nt Np√K - 1)/N t), where Np denotes the number of antennas of primary receiver, Q is the interference temperature, and K represents the number of secondary transmitters. © 2013 IEEE.

  17. From bad pharma to good pharma: aligning market forces with good and trustworthy practices through accreditation, certification, and rating.

    Science.gov (United States)

    Miller, Jennifer E

    2013-01-01

    This article explores whether the bioethical performance and trustworthiness of pharmaceutical companies can be improved by harnessing market forces through the use of accreditation, certification, or rating. Other industries have used such systems to define best practices, set standards, and assess and signal the quality of services, processes, and products. These systems have also informed decisions in other industries about where to invest, what to buy, where to work, and when to regulate. Similarly, accreditation, certification, and rating programs can help drug companies address stakeholder concerns in four areas: clinical trial design and management, dissemination of clinical trial results, marketing practices, and the accessibility of medicines. To illuminate processes - such as conflicts of interests and revolving-door policies - that can jeopardize the integrity of accreditation, certification, and ratings systems, the article concludes with a consideration of recent failures of credit-rating agencies and a review of the regulatory capture literature.

  18. Acute effects of whole-body vibration on jump force and jump rate of force development: a comparative study of different devices.

    Science.gov (United States)

    Bagheri, Javad; van den Berg-Emons, Rita J; Pel, Johan J; Horemans, Herwin L; Stam, Henk J

    2012-03-01

    The goal of this study was to compare the acute effects of whole-body vibration (WBV) delivered by 3 devices with different mechanical behavior on jump force (JF) and jump rate of force development (JRFD). Twelve healthy persons (4 women and 8 men; age 30.5 ± 8.8 years; height 178.6 ± 7.3 cm; body mass 74.8 ± 9.7 kg) were exposed to WBV for 15 and 40 seconds using 2 professional devices (power plate [PP; vertical vibration] and Galileo 2000 [GA; oscillatory motion around the horizontal axis in addition to vertical vibration]) and a home-use device [Power Maxx, PM; horizontal vibration]). The JF and JRFD were evaluated before, immediately after, and 5 minutes after WBV. The JF measured immediately after 40 seconds of vibration by the GA device was reduced (3%, p = 0.05), and JRFD measured after 5 minutes of rest after 40 seconds of vibration by the PM device was reduced (12%, p < 0.05) compared with the baseline value. The acute effects of WBV (15 or 40 seconds) on JF and JRFD were not significantly different among the 3 devices. In conclusion, our hypothesis that WBV devices with different mechanical behaviors would result in different acute effects on muscle performance was not confirmed.

  19. Acute effect of static stretching on rate of force development and maximal voluntary contraction in older women.

    Science.gov (United States)

    Gurjão, André L D; Gonçalves, Raquel; de Moura, Rodrigo F; Gobbi, Sebastião

    2009-10-01

    The purpose of this study was to investigate, in older women, the acute effect of static stretching (SS) on both muscle activation and force output. Twenty-three older women (64.6 +/- 7.1 yr) participated in the study. The maximal voluntary contraction (MVC), rate of force development (RFD) (50, 100, 150, and 200 ms relative to onset of muscular contraction), and peak RFD (PRFD) (the steepest slope of the curve during the first 200 ms) were tested under 2 randomly separate conditions: SS and control (C). Electromyographic (EMG) activity of the vastus medialis (VM), vastus lateralis (VL), and biceps femoris (BF) muscles also was assessed. The MVC was significantly lower (p force decreased after their performance of SS exercises. The mechanisms responsible for this effect do not appear to be related to muscle activation. Thus, if flexibility is to be trained, it is recommended that SS does not occur just before the performance of activities that require high levels of muscular force.

  20. Shipwreck rates reveal Caribbean tropical cyclone response to past radiative forcing

    Science.gov (United States)

    Trouet, Valerie; Harley, Grant L.; Domínguez-Delmás, Marta

    2016-03-01

    Assessing the impact of future climate change on North Atlantic tropical cyclone (TC) activity is of crucial societal importance, but the limited quantity and quality of observational records interferes with the skill of future TC projections. In particular, North Atlantic TC response to radiative forcing is poorly understood and creates the dominant source of uncertainty for twenty-first-century projections. Here, we study TC variability in the Caribbean during the Maunder Minimum (MM; 1645-1715 CE), a period defined by the most severe reduction in solar irradiance in documented history (1610-present). For this purpose, we combine a documentary time series of Spanish shipwrecks in the Caribbean (1495-1825 CE) with a tree-growth suppression chronology from the Florida Keys (1707-2009 CE). We find a 75% reduction in decadal-scale Caribbean TC activity during the MM, which suggests modulation of the influence of reduced solar irradiance by the cumulative effect of cool North Atlantic sea surface temperatures, El Niño-like conditions, and a negative phase of the North Atlantic Oscillation. Our results emphasize the need to enhance our understanding of the response of these oceanic and atmospheric circulation patterns to radiative forcing and climate change to improve the skill of future TC projections.

  1. Nanofluids mediating surface forces.

    Science.gov (United States)

    Pilkington, Georgia A; Briscoe, Wuge H

    2012-11-01

    Fluids containing nanostructures, known as nanofluids, are increasingly found in a wide array of applications due to their unique physical properties as compared with their base fluids and larger colloidal suspensions. With several tuneable parameters such as the size, shape and surface chemistry of nanostructures, as well as numerous base fluids available, nanofluids also offer a new paradigm for mediating surface forces. Other properties such as local surface plasmon resonance and size dependent magnetism of nanostructures also present novel mechanisms for imparting tuneable surface interactions. However, our fundamental understanding, experimentally and theoretically, of how these parameters might affect surface forces remains incomplete. Here we review recent results on equilibrium and dynamic surface forces between macroscopic surfaces in nanofluids, highlighting the overriding trends in the correlation between the physical parameters that characterise nanofluids and the surface forces they mediate. We also discuss the challenges that confront existing surface force knowledge as a result of this new paradigm.

  2. Overriding "doing wrong" and "not doing right": validation of the Dispositional Self-Control Scale (DSC).

    Science.gov (United States)

    Ein-Gar, Danit; Sagiv, Lilach

    2014-01-01

    We present the Dispositional Self-Control (DSC) Scale, which reflects individuals' tendency to override 2 types of temptations, termed doing wrong and not doing right. We report a series of 5 studies designed to test the reliability and validity of the scale. As hypothesized, high DSC predicts distant future orientation and low DSC predicts deviant behaviors such as aggression, alcohol misuse, and aberrant driving. DSC also predicts task performance among resource-depleted participants. Taken together, these findings suggest that the DSC Scale could be a useful tool toward further understanding the role of personality in overcoming self-control challenges.

  3. Metabolic Rate and Ground Reaction Force During Motorized and Non-Motorized Treadmill Exercise

    Science.gov (United States)

    Everett, Meghan E.; Loehr, James A.; DeWitt, John K.; Laughlin, Mitzi; Lee, Stuart M. C.

    2010-01-01

    PURPOSE: To measure vertical ground reaction force (vGRF) and oxygen consumption (VO2) at several velocities during exercise using a ground-based version of the ISS treadmill in the M and NM modes. METHODS: Subjects (n = 20) walked or ran at 0.89, 1.34, 1.79, 2.24, 2.68, and 3.12 m/s while VO2 and vGRF data were collected. VO2 was measured using open-circuit spirometry (TrueOne 2400, Parvo-Medics). Data were averaged over the last 2 min of each 5-min stage. vGRF was measured in separate 15-s bouts at 125 Hz using custom-fitted pressure-sensing insoles (F-Scan Sport Sensors, Tekscan, Inc). A repeated-measures ANOVA was used to test for differences in VO2 and vGRF between M and NM and across speeds. Significance was set at P < 0.05. RESULTS: Most subjects were unable to exercise for 5 min at treadmill speeds above 1.79 m/s in the NM mode; however, vGRF data were obtained for all subjects at each speed in both modes. VO2 was approx.40% higher during NM than M exercise across treadmill speeds. vGRF increased with treadmill speed but was not different between modes. CONCLUSION: Higher VO2 with no change in vGRF suggests that the additional metabolic cost associated with NM treadmill exercise is accounted for in the horizontal forces required to move the treadmill belt. Although this may limit the exercise duration at faster speeds, high-intensity NM exercise activates the hamstrings and plantarflexors, which are not specifically targeted or well protected by other in-flight countermeasures.

  4. The Forecasting of Labour Force Participation and the Unemployment Rate in Poland and Turkey Using Fuzzy Time Series Methods

    Directory of Open Access Journals (Sweden)

    Yolcu Ufuk

    2016-06-01

    Full Text Available Fuzzy time series methods based on the fuzzy set theory proposed by Zadeh (1965 was first introduced by Song and Chissom (1993. Since fuzzy time series methods do not have the assumptions that traditional time series do and have effective forecasting performance, the interest on fuzzy time series approaches is increasing rapidly. Fuzzy time series methods have been used in almost all areas, such as environmental science, economy and finance. The concepts of labour force participation and unemployment have great importance in terms of both the economy and sociology of countries. For this reason there are many studies on their forecasting. In this study, we aim to forecast the labour force participation and unemployment rate in Poland and Turkey using different fuzzy time series methods.

  5. Schizophrenia, delusional symptoms, and violence: the threat/control override concept reexamined.

    Science.gov (United States)

    Stompe, Thomas; Ortwein-Swoboda, Gerhard; Schanda, Hans

    2004-01-01

    In 1994 Link and Stueve identified a number of symptoms--called threat/control-override (TCO) symptoms--that were significantly more than others related to violence. This was confirmed by some, but not all, following studies. The contradictory results could be due to remarkable differences in sample compositions, sources used, and definitions and periods of recorded violence, but they are mainly due to problems defining the TCO symptoms. To reexamine the validity of the TCO concept from an exclusively psychopathological position, we compared in a retrospective design a sample of male offenders with schizophrenia not guilty by reason of insanity (n = 119) with a matched sample of nonoffending schizophrenia patients (n = 105). We could find no significant differences regarding the prevalence of TCO symptoms in the two groups during the course of illness. The only statistically significant discriminating factors were social origin and substance abuse. Yet, taking into account the severity of offenses, TCO symptoms emerged as being associated with severe violence. This effect is primarily attributable to the comparatively unspecific threat symptoms. Control-override, to be seen as more or less typical for schizophrenia, showed no significant association with the severity of violent behavior.

  6. A Novel Method for Quantifying the Inhaled Dose of Air Pollutants Based on Heart Rate, Breathing Rate and Forced Vital Capacity.

    Directory of Open Access Journals (Sweden)

    Roby Greenwald

    Full Text Available To better understand the interaction of physical activity and air pollution exposure, it is important to quantify the change in ventilation rate incurred by activity. In this paper, we describe a method for estimating ventilation using easily-measured variables such as heart rate (HR, breathing rate (fB, and forced vital capacity (FVC. We recruited healthy adolescents to use a treadmill while we continuously measured HR, fB, and the tidal volume (VT of each breath. Participants began at rest then walked and ran at increasing speed until HR was 160-180 beats per minute followed by a cool down period. The novel feature of this method is that minute ventilation ([Formula: see text] was normalized by FVC. We used general linear mixed models with a random effect for subject and identified nine potential predictor variables that influence either [Formula: see text] or FVC. We assessed predictive performance with a five-fold cross-validation procedure. We used a brute force selection process to identify the best performing models based on cross-validation percent error, the Akaike Information Criterion and the p-value of parameter estimates. We found a two-predictor model including HR and fB to have the best predictive performance ([Formula: see text]/FVC = -4.247+0.0595HR+0.226fB, mean percent error = 8.1±29%; however, given the ubiquity of HR measurements, a one-predictor model including HR may also be useful ([Formula: see text]/FVC = -3.859+0.101HR, mean percent error = 11.3±36%.

  7. A Novel Method for Quantifying the Inhaled Dose of Air Pollutants Based on Heart Rate, Breathing Rate and Forced Vital Capacity.

    Science.gov (United States)

    Greenwald, Roby; Hayat, Matthew J; Barton, Jerusha; Lopukhin, Anastasia

    2016-01-01

    To better understand the interaction of physical activity and air pollution exposure, it is important to quantify the change in ventilation rate incurred by activity. In this paper, we describe a method for estimating ventilation using easily-measured variables such as heart rate (HR), breathing rate (fB), and forced vital capacity (FVC). We recruited healthy adolescents to use a treadmill while we continuously measured HR, fB, and the tidal volume (VT) of each breath. Participants began at rest then walked and ran at increasing speed until HR was 160-180 beats per minute followed by a cool down period. The novel feature of this method is that minute ventilation ([Formula: see text]) was normalized by FVC. We used general linear mixed models with a random effect for subject and identified nine potential predictor variables that influence either [Formula: see text] or FVC. We assessed predictive performance with a five-fold cross-validation procedure. We used a brute force selection process to identify the best performing models based on cross-validation percent error, the Akaike Information Criterion and the p-value of parameter estimates. We found a two-predictor model including HR and fB to have the best predictive performance ([Formula: see text]/FVC = -4.247+0.0595HR+0.226fB, mean percent error = 8.1±29%); however, given the ubiquity of HR measurements, a one-predictor model including HR may also be useful ([Formula: see text]/FVC = -3.859+0.101HR, mean percent error = 11.3±36%).

  8. The Effect of Additional Police Force on Crime Rate: Evidence from Women's Japan Basketball League

    OpenAIRE

    Hiroya Kawashima

    2012-01-01

    This paper analyzes influence of an additional referee on number of fouls by using the data from Women's Japan Basketball League (WJBL) in order to examine whether number of police officers affects the crime rate. For the season of 2010-2011, the upper league of the WJBL introduced three-referee system for the adaption of the international standard. Using this natural experiment, the Difference in Difference and the Instrumental Variable method are used to remove endogeneity. The results indi...

  9. Reduction in single muscle fiber rate of force development with aging is not attenuated in world class older masters athletes.

    Science.gov (United States)

    Power, Geoffrey A; Minozzo, Fábio C; Spendiff, Sally; Filion, Marie-Eve; Konokhova, Yana; Purves-Smith, Maddy F; Pion, Charlotte; Aubertin-Leheudre, Mylène; Morais, José A; Herzog, Walter; Hepple, Russell T; Taivassalo, Tanja; Rassier, Dilson E

    2016-02-15

    Normal adult aging is associated with impaired muscle contractile function; however, to what extent cross-bridge kinetics are altered in aging muscle is not clear. We used a slacken restretch maneuver on single muscle fiber segments biopsied from the vastus lateralis of young adults (∼23 yr), older nonathlete (NA) adults (∼80 yr), and age-matched world class masters athletes (MA; ∼80 yr) to assess the rate of force redevelopment (ktr) and cross-bridge kinetics. A post hoc analysis was performed, and only the mechanical properties of "slow type" fibers based on unloaded shortening velocity (Vo) measurements are reported. The MA and NA were ∼54 and 43% weaker, respectively, for specific force compared with young. Similarly, when force was normalized to cross-sectional area determined via the fiber shape angularity data, both old groups did not differ, and the MA and NA were ∼43 and 48% weaker, respectively, compared with young (P < 0.05). Vo for both MA and NA old groups was 62 and 46% slower, respectively, compared with young. Both MA and NA adults had approximately two times slower values for ktr compared with young. The slower Vo in both old groups relative to young, coupled with a similarly reduced ktr, suggests impaired cross-bridge kinetics are responsible for impaired single fiber contractile properties with aging. These results challenge the widely accepted resilience of slow type fibers to cellular aging.

  10. Override of the radiation-induced mitotic block in human tumour cells by methylxanthines and its relationship to the potentiation of cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Musk, S.R.R.; Steel, G.G. (Institute of Cancer Research, Sutton (UK). Surrey Branch)

    1990-06-01

    Caffeine, theophylline, theobromine and paraxanthine, were tested for ability to override mitotic block induced by ionizing radiation in the human bladder carcinoma cell line RT112. All were found to partially override the block, at a concentration of 1mM in the order caffeine > theophylline > theobromine = paraxanthine. At a concentration of 1 mM only caffeine was found to potentiate cell killing as well as causing block override; at higher concentrations all had a significant effect on survival but little or no further influence on the degree of block override. It is concluded that override of a mitotic block is not in itself sufficient to cause increased killing when irradiated cells are incubated in the presence of caffeine, and that caffeine exerts its potentiating effect by directly inhibiting repair of damage in DNA or by causing override of radiation-induced inhibition of DNA synthesis. (author).

  11. Explosive Resistance Training Increases Rate of Force Development in Ankle Dorsiflexors and Gait Function in Adults With Cerebral Palsy.

    Science.gov (United States)

    Kirk, Henrik; Geertsen, Svend S; Lorentzen, Jakob; Krarup, Kasper B; Bandholm, Thomas; Nielsen, Jens B

    2016-10-01

    Kirk, H, Geertsen, SS, Lorentzen, J, Krarup, KB, Bandholm, T, and Nielsen, JB. Explosive resistance training increases rate of force development in ankle dorsiflexors and gait function in adults with cerebral palsy. J Strength Cond Res 30(10): 2749-2760, 2016-Alterations in passive elastic properties of muscles and reduced ability to quickly generate muscle force contribute to impaired gait function in adults with cerebral palsy (CP). In this study, we investigated whether 12 weeks of explosive and progressive heavy-resistance training (PRT) increases rate of force development of ankle dorsiflexors (RFDdf), improves gait function, and affects passive ankle joint stiffness in adults with CP. Thirty-five adults (age: 36.5; range: 18-59 years) with CP were nonrandomly assigned to a PRT or nontraining control (CON) group in this explorative trial. The PRT group trained ankle dorsiflexion, plantarflexion, leg press, hamstring curls, abdominal curls, and back extension 3 days per week for 12 weeks, with 3 sets per exercise and progressing during the training period from 12 to 6 repetition maximums. RFDdf, 3-dimensional gait analysis, functional performance, and ankle joint passive and reflex-mediated muscle stiffness were evaluated before and after. RFDdf increased significantly after PRT compared to CON. PRT also caused a significant increase in toe lift late in swing and a significantly more dorsiflexed ankle joint at ground contact and during stance. The increased toe-lift amplitude was correlated to the increased RFDdf (r = 0.73). No other between-group differences were observed. These findings suggest that explosive PRT may increase RFDdf and facilitate larger range of movement in the ankle joint during gait. Explosive PRT should be tested in clinical practice as part of a long-term training program for adults with CP.

  12. Solar-forced diurnal regulation of cave drip rates via phreatophyte evapotranspiration

    Science.gov (United States)

    Coleborn, Katie; Rau, Gabriel C.; Cuthbert, Mark O.; Baker, Andy; Navarre, Owen

    2016-11-01

    We present results of a detailed study of drip rate variations at 12 drip discharge sites in Glory Hole Cave, New South Wales, Australia. Our novel time series analysis, using the wavelet synchrosqueezed transform, reveals pronounced oscillations at daily and sub-daily frequencies occurring in 8 out of the 12 monitored sites. These oscillations were not spatially or temporally homogenous, with different drip sites exhibiting such behaviour at different times of year in different parts of the cave. We test several hypotheses for the cause of the oscillations, including variations in pressure gradients between karst and cave due to cave breathing effects or atmospheric and earth tides, variations in hydraulic conductivity due to changes in viscosity of water with daily temperature oscillations, and solar-driven daily cycles of vegetative (phreatophytic) transpiration. We conclude that the only hypothesis consistent with the data and hydrologic theory is that daily oscillations are caused by solar-driven pumping by phreatophytic trees which are abundant at the site. The daily oscillations are not continuous and occur sporadically in short bursts (2-14 days) throughout the year due to non-linear modification of the solar signal via complex karst architecture. This is the first indirect observation leading to the hypothesis of tree water use in cave drip water. It has important implications for karst hydrology in regards to developing a new protocol to determine the relative importance of trends in drip rate, such as diurnal oscillations, and how these trends change over timescales of weeks to years. This information can also be used to infer karst architecture. This study demonstrates the importance of vegetation on recharge dynamics, information that will inform both process-based karst models and empirical estimation approaches. Our findings support a growing body of research exploring the impact of trees on speleothem paleoclimate proxies.

  13. Musculotendinous Stiffness of Triceps Surae, Maximal Rate of Force Development, and Vertical Jump Performance

    Directory of Open Access Journals (Sweden)

    Tarak Driss

    2015-01-01

    Full Text Available The relationships between ankle plantar flexor musculotendinous stiffness (MTS and performance in a countermovement vertical jump (CMJ and maximal rate of torque development (MRTD were studied in 27 active men. MTS was studied by means of quick releases at 20 (S0.2, 40 (S0.4, 60 (S0.6, and 80% (S0.8 of maximal voluntary torque (TMVC. CMJ was not correlated with strength indices but was positively correlated with MRTD/BM, S0.4/BM. The slope α2 and intercept β2 of the torque-stiffness relationships from 40 to 80% TMVC were correlated negatively (α2 and positively (β2 with CMJ. The different stiffness indices were not correlated with MRTD. The prediction of CMJ was improved by the introduction of MRTD in multiple regressions between CMJ and stiffness. CMJ was also negatively correlated with indices of curvature of the torque-stiffness relationship. The subjects were subdivided in 3 groups in function of CMJ (groups H, M, and L for high, medium, and low performers, resp.. There was a downward curvature of the torque-stiffness relationship at high torques in group H or M and the torque-stiffness regression was linear in group L only. These results suggested that torque-stiffness relationships with a plateau at high torques are more frequent in the best jumpers.

  14. Musculotendinous stiffness of triceps surae, maximal rate of force development, and vertical jump performance.

    Science.gov (United States)

    Driss, Tarak; Lambertz, Daniel; Rouis, Majdi; Jaafar, Hamdi; Vandewalle, Henry

    2015-01-01

    The relationships between ankle plantar flexor musculotendinous stiffness (MTS) and performance in a countermovement vertical jump (CMJ) and maximal rate of torque development (MRTD) were studied in 27 active men. MTS was studied by means of quick releases at 20 (S0.2), 40 (S0.4), 60 (S0.6), and 80% (S0.8) of maximal voluntary torque (T(MVC)). CMJ was not correlated with strength indices but was positively correlated with MRTD/BM, S 0.4/BM. The slope α 2 and intercept β 2 of the torque-stiffness relationships from 40 to 80% T(MVC) were correlated negatively (α 2) and positively (β 2) with CMJ. The different stiffness indices were not correlated with MRTD. The prediction of CMJ was improved by the introduction of MRTD in multiple regressions between CMJ and stiffness. CMJ was also negatively correlated with indices of curvature of the torque-stiffness relationship. The subjects were subdivided in 3 groups in function of CMJ (groups H, M, and L for high, medium, and low performers, resp.). There was a downward curvature of the torque-stiffness relationship at high torques in group H or M and the torque-stiffness regression was linear in group L only. These results suggested that torque-stiffness relationships with a plateau at high torques are more frequent in the best jumpers.

  15. Tumor suppression by miR-26 overrides potential oncogenic activity in intestinal tumorigenesis

    Science.gov (United States)

    Zeitels, Lauren R.; Acharya, Asha; Shi, Guanglu; Chivukula, Divya; Chivukula, Raghu R.; Anandam, Joselin L.; Abdelnaby, Abier A.; Balch, Glen C.; Mansour, John C.; Yopp, Adam C.; Richardson, James A.

    2014-01-01

    Down-regulation of miR-26 family members has been implicated in the pathogenesis of multiple malignancies. In some settings, including glioma, however, miR-26-mediated repression of PTEN promotes tumorigenesis. To investigate the contexts in which the tumor suppressor versus oncogenic activity of miR-26 predominates in vivo, we generated miR-26a transgenic mice. Despite measureable repression of Pten, elevated miR-26a levels were not associated with malignancy in transgenic animals. We documented reduced miR-26 expression in human colorectal cancer and, accordingly, showed that miR-26a expression potently suppressed intestinal adenoma formation in Apcmin/+ mice, a model known to be sensitive to Pten dosage. These studies reveal a tumor suppressor role for miR-26 in intestinal cancer that overrides putative oncogenic activity, highlighting the therapeutic potential of miR-26 delivery to this tumor type. PMID:25395662

  16. A Case Study of True and Fair View Override in Financial Reporting

    Directory of Open Access Journals (Sweden)

    Ho Horace

    2016-12-01

    Full Text Available This paper documents a case study of true and fair view override in financial reporting by a multinational firm subject to International Financial Reporting Standards (IFRSs. The 2009 Interim Report of HSBC Holdings plc states that HSBC departed from the requirements of IAS 32 Financial Instruments: Presentation (IAS 32. Notwithstanding its noncompliance with the IFRSs, HSBC (2009 concluded that “the interim consolidated financial statements prepared on this basis presented fairly, and gave a true and fair view of the Group’s financial position, financial performance and cash flows” (p. 2. The purpose of this paper is to evaluate critically the accounting treatment in light of the relevant requirements of the IFRSs and the implications for professional accounting standards arising from this departure.

  17. Influence Of Changing the Flow Rate In The Acoustic Response And Saturation During Forced Imbibition In A Limestone

    Science.gov (United States)

    Lopes, S.; Lebedev, M.; Muller, T. M.

    2012-12-01

    Forced imbibition was performed in a Limestone Savonnieres by injecting water into a dry sample. The injection was monitored with X-ray Computed Tomography (CT) and active ultrasonic measurements so that the time-space distribution of the invading fluid could be simultaneously observed in CT images and quantified through measuring P-wave velocities and water saturation. The CT scans allowed us to observe a water front advancing away from the area of injection and estimate saturation. Through the evolution of P-wave velocities, we observed that the approaching of the water front to the monitored position decreased P-wave velocities while the saturation increased continuously. Decreasing injection rate decreased P-wave velocities and saturation. Increasing injection rate, increased P-wave velocities and saturation, sharply and for a short period of time followed by a slight decrease for P-wave velocities and a continuous increase. Our experimental data confirms how sensitive acoustic waves are to the presence of water and that changing injection rates promote considerable fluid distribution that is drastically reflected in the acoustic velocities. Furthermore, the same patterns have been observed in our previous work with sandstones.; Waveforms for the P-waves picked during this experiment: before injection (blue line) and after injecting 8.4 mL of volume of water (orange line). Note the decrease of wave-amplitude and increase of wavelength. ; P-wave velocities with volume of water injected. Dashed lines represent the moments when we decreased injection rate, at 7.9 mL of volume of water injected, and when we increased injection rate at 10.7 mL. Note the immediate decrease and increase of P-wave velocity when we decrease and increase the injection rate, respectively.

  18. Hacking the thylakoid proton motive force for improved photosynthesis: modulating ion flux rates that control proton motive force partitioning into Δψ and ΔpH.

    Science.gov (United States)

    Davis, Geoffry A; Rutherford, A William; Kramer, David M

    2017-09-26

    There is considerable interest in improving plant productivity by altering the dynamic responses of photosynthesis in tune with natural conditions. This is exemplified by the 'energy-dependent' form of non-photochemical quenching (qE), the formation and decay of which can be considerably slower than natural light fluctuations, limiting photochemical yield. In addition, we recently reported that rapidly fluctuating light can produce field recombination-induced photodamage (FRIP), where large spikes in electric field across the thylakoid membrane (Δψ) induce photosystem II recombination reactions that produce damaging singlet oxygen ((1)O2). Both qE and FRIP are directly linked to the thylakoid proton motive force (pmf), and in particular, the slow kinetics of partitioning pmf into its ΔpH and Δψ components. Using a series of computational simulations, we explored the possibility of 'hacking' pmf partitioning as a target for improving photosynthesis. Under a range of illumination conditions, increasing the rate of counter-ion fluxes across the thylakoid membrane should lead to more rapid dissipation of Δψ and formation of ΔpH. This would result in increased rates for the formation and decay of qE while resulting in a more rapid decline in the amplitudes of Δψ-spikes and decreasing (1)O2 production. These results suggest that ion fluxes may be a viable target for plant breeding or engineering. However, these changes also induce transient, but substantial mismatches in the ATP : NADPH output ratio as well as in the osmotic balance between the lumen and stroma, either of which may explain why evolution has not already accelerated thylakoid ion fluxes. Overall, though the model is simplified, it recapitulates many of the responses seen in vivo, while spotlighting critical aspects of the complex interactions between pmf components and photosynthetic processes. By making the programme available, we hope to enable the community of photosynthesis researchers to

  19. Force Field Parametrization of Colloidal CdSe Nanocrystals Using an Adaptive Rate Monte Carlo Optimization Algorithm.

    Science.gov (United States)

    Cosseddu, Salvatore; Infante, Ivan

    2017-01-10

    In a typical colloidal CdSe nanocrystal more than 50% of the atoms are located at the surface. These atoms can give rise to electronic traps that can deteriorate the performance of optoelectronic devices made of these nanomaterials. A key challenge in this field is thus to understand with atomistic detail the chemical processes occurring at the nanocrystal surface. Molecular dynamics simulations represent an important tool to unveil these processes, but its implementation is strongly limited by the difficulties of finely tuning classical force fields parameters, primarily caused by the unavailability of experimental data of these materials that are suitable in the parametrization procedures. In this work, we present a general scheme to produce force field parameters from first-principles calculations. This approach is based on a newly developed stochastic optimization algorithm called Adaptive Rate Monte Carlo, which is designed to be robust, accurate, easy-to-use, and flexible enough to be straightforwardly extended to other nanomaterials. We demonstrate that our algorithm provides a set of parameters capable of satisfactorily describing nonstoichiometric CdSe nanocrystals passivated with oleate ligands akin to experimental conditions. We also demonstrate that our new parameters are robust enough to be transferable among crystal structures and nanocrystals of increasing sizes up to the bulk.

  20. Design and Analysis of a High Force, Low Voltage and High Flow Rate Electro-Thermal Micropump

    Directory of Open Access Journals (Sweden)

    Ghader Yosefi

    2014-12-01

    Full Text Available This paper presents the design and simulation of an improved electro-thermal micromachined pump for drug delivery applications. Thermal actuators, which are a type of Micro Electro Mechanical system (MEMS device, are highly useful because of their ability to deliver with great force and displacement. Thus, our structure is based on a thermal actuator that exploits the Joule heating effect and has been improved using the springy length properties of MEMS chevron beams. The Joule heating effect results in a difference in temperature and therefore displacement in the beams (actuators. Simulation results show that a maximum force of 4.4 mN and a maximum flow rate of 16 μL/min can be obtained by applying an AC voltage as low as 8 V at different frequencies ranging from 1 to 32 Hz. The maximum temperature was a problem at the chevron beams and the center shaft. Thus, to locally increase the temperature of the chevron beams alone and not that of the pumping diaphragm: (1 The air gaps 2 μm underneath and above the device layer were optimized for heat transfer. (2 Release holes and providing fins were created at the center shaft and actuator, respectively, to decrease the temperature by approximately 10 °C. (3 We inserted and used a polymer tube to serve as an insulator and eliminate leakage problems in the fluidic channel.

  1. Numerical Simulations of Turbulent Molecular Clouds Regulated by Radiation Feedback Forces. I. Star Formation Rate and Efficiency

    Science.gov (United States)

    Raskutti, Sudhir; Ostriker, Eve C.; Skinner, M. Aaron

    2016-10-01

    Radiation feedback from stellar clusters is expected to play a key role in setting the rate and efficiency of star formation in giant molecular clouds. To investigate how radiation forces influence realistic turbulent systems, we have conducted a series of numerical simulations employing the Hyperion radiation hydrodynamics solver, considering the regime that is optically thick to ultraviolet and optically thin to infrared radiation. Our model clouds cover initial surface densities between Σ cl,0∼ 10--300 M⊙ pc-2, with varying initial turbulence. We follow them through turbulent, self-gravitating collapse, star cluster formation, and cloud dispersal by stellar radiation. All our models display a log-normal distribution of gas surface density Σ for an initial virial parameter αvir,0=2, the log-normal standard deviation is σln Σ =1-1.5 and the star formation rate coefficient ɛff,ρ=0.3-0.5, both of which are sensitive to turbulence but not radiation feedback. The net star formation efficiency (SFE) ɛfinal increases with Σcl,0 and decreases with α vir,0. We interpret these results via a simple conceptual framework, whereby steady star formation increases the radiation force, such that local gas patches at successively higher Σ become unbound. Based on this formalism (with fixed σln Σ), we provide an analytic upper bound on ɛfinal, which is in good agreement with our numerical results. The final SFE depends on the distribution of Eddington ratios in the cloud and is strongly increased by the turbulent compression of gas.

  2. Numerical Simulations of Turbulent, Molecular Clouds Regulated by Radiation Feedback Forces I: Star Formation Rate and Efficiency

    CERN Document Server

    Raskutti, Sudhir; Skinner, M Aaron

    2016-01-01

    Radiation feedback from stellar clusters is expected to play a key role in setting the rate and efficiency of star formation in giant molecular clouds (GMCs). To investigate how radiation forces influence realistic turbulent systems, we have conducted a series of numerical simulations employing the {\\it Hyperion} radiation hydrodynamics solver, considering the regime that is optically thick to ultraviolet (UV) and optically thin to infrared (IR) radiation. Our model clouds cover initial surface densities between $\\Sigma_{\\rm cl,0} \\sim 10-300~M_{\\odot}~{\\rm pc^{-2}}$, with varying initial turbulence. We follow them through turbulent, self-gravitating collapse, formation of star clusters, and cloud dispersal by stellar radiation. All our models display a lognormal distribution of gas surface density $\\Sigma$; for an initial virial parameter $\\alpha_{\\rm vir,0} = 2$, the lognormal standard deviation is $\\sigma_{\\rm ln \\Sigma} = 1-1.5$ and the star formation rate coefficient $\\varepsilon_{\\rm ff,\\bar\\rho} = 0.3-...

  3. A rapid rotation to an inverted seated posture inhibits muscle force, activation, heart rate and blood pressure.

    Science.gov (United States)

    Johar, Pramod; Grover, Varun; DiSanto, Mario C; Button, Duane C; Behm, David G

    2013-08-01

    Although previous studies have demonstrated neuromuscular and cardiovascular changes with slow inversion rates, emergencies, such as overturned vehicles and helicopters can occur rapidly. The purpose of this study was to investigate changes in neuromuscular and cardiovascular responses with rapid (1 s) and slower (3 s) transitions from upright to inverted seated positions. Twenty-two subjects performed separate and concurrent unilateral elbow flexion and leg extension maximal voluntary contractions (MVCs) for 6 s in an upright seated position and when inverted with 1 and 3 s rotations. Elbow flexion and leg extension force; biceps, triceps, quadriceps and hamstrings electromyographic (EMG) activity, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured. Whether the elbow flexion or leg extension contractions occurred concurrently or individually, significant (p leg extension MVC as compared to the initial second of rotation to inversion. HR, SBP and DBP demonstrated (p < 0.001) decreases when inverted within 1 and 3 s rotations as compared to upright. In conclusion, this is the first study to show that irrespective of rotation speed, inversion inhibited neuromuscular and cardiovascular responses, similar to the more deliberate, slower rotation of previous inversion studies.

  4. Maximal strength training improves work economy, rate of force development and maximal strength more than conventional strength training.

    Science.gov (United States)

    Heggelund, Jørn; Fimland, Marius S; Helgerud, Jan; Hoff, Jan

    2013-06-01

    This study compared maximal strength training (MST) with equal training volume (kg × sets × repetitions) of conventional strength training (CON) primarily with regard to work economy, and second one repetition maximum (1RM) and rate of force development (RFD) of single leg knee extension. In an intra-individual design, one leg was randomized to knee-extension MST (4 or 5RM) and the other leg to CON (3 × 10RM) three times per week for 8 weeks. MST was performed with maximal concentric mobilization of force while CON was performed with moderate velocity. Eight untrained or moderately trained men (26 ± 1 years) completed the study. The improvement in gross work economy was -0.10 ± 0.08 L min(-1) larger after MST (P = 0.011, between groups). From pre- to post-test the MST and CON improved net work economy with 31 % (P < 0.001) and 18 % (P = 0.01), respectively. Compared with CON, the improvement in 1RM and dynamic RFD was 13.7 ± 8.4 kg (P = 0.002) and 587 ± 679 N s(-1) (P = 0.044) larger after MST, whereas isometric RFD was of borderline significance 3,028 ± 3,674 N s(-1) (P = 0.053). From pre- to post-test, MST improved 1RM and isometric RFD with 50 % (P < 0.001) and 155 % (P < 0.001), respectively whereas CON improved 1RM and isometric RFD with 35 % (P < 0.001) and 83 % (P = 0.028), respectively. Anthropometric measures of quadriceps femoris muscle mass and peak oxygen uptake did not change. In conclusion, 8 weeks of MST was more effective than CON for improving work economy, 1RM and RFD in untrained and moderately trained men. The advantageous effect of MST to improve work economy could be due to larger improvements in 1RM and RFD.

  5. Influence of muscle-tendon unit structure on rate of force development during the squat, countermovement, and drop jumps.

    Science.gov (United States)

    Earp, Jacob E; Kraemer, William J; Cormie, Prue; Volek, Jeffery S; Maresh, Carl M; Joseph, Michael; Newton, Robert U

    2011-02-01

    Previous research has highlighted the importance of muscle and tendon structure to stretch shortening cycle performance. However, the relationships between muscle and tendon structure to performance are highly dependent on the speed and intensity of the movement. The purpose of this study was to determine if muscle and tendon structure is associated with the rate of force development (RFD) throughout static squat jump (SJ), countermovement jump (CMJ), and drop jump (DJ; 30-cm height). Twenty-five strength- and power-trained men participated in the study. Using ultrasonography, vastus lateralis (VL) and gastrocnemius (GAS) pennation (PEN) and fascicle length (FL), and Achilles tendon (AT) thickness and length were measured. Subjects then performed SJ, CMJ, and DJ, during which RFD was calculated over time 5 distinct time intervals. During CMJs, early RFD could be predicted between 0 and 10 milliseconds by both GAS-FL (r² = 0.213, β = 0.461) and AT-length (r² = 0.191, β = 20.438). Between 10 and 30 milliseconds GAS-FL was a significant predictor of CMJ-RFD (r² = 0.218, β = 0.476). During DJ, initial RFD (0-10 milliseconds) could be significantly predicted by GAS-FL (r² = 0.185, β = 20.434), VL-PEN (r² = 0.189, β = 0.435), and GAS-PEN (r² = 0.188, β = 0.434). These findings suggest that longer ATs may have increased elasticity, which can decrease initial RFD during CMJ; thus, their use in talent identification is not recommended. The GAS fascicle length had an intensity-dependent relationship with RFD, serving to positively predict RFD during early CMJs and an inverse predictor during early DJs. During DDJs, subjects with greater PEN were better able to redirected initial impact forces. Although both strength and plyometric training have been shown to increase FL, only heavy strength training has been shown to increase PEN. Thus, when a high eccentric load or multiple jumps are required, heavy strength training might be used to elicit muscular adaptations

  6. Training-induced changes in muscle CSA, muscle strength, EMG, and rate of force development in elderly subjects after long-term unilateral disuse

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Aagaard, Per; Rosted, Anna

    2004-01-01

    , the present study examined the effect of three types of training regimes after unilateral prolonged disuse and subsequent hip-replacement surgery on maximal muscle strength, rapid muscle force [rate of force development (RFD)], muscle activation, and muscle size. Thirty-six subjects (60-86 yr) were randomized......The ability to develop muscle force rapidly may be a very important factor to prevent a fall and to perform other tasks of daily life. However, information is still lacking on the range of training-induced neuromuscular adaptations in elderly humans recovering from a period of disuse. Therefore...

  7. NPM phosphorylation stimulates Cdk1, overrides G2/M checkpoint and increases leukemic blasts in mice.

    Science.gov (United States)

    Du, Wei; Zhou, Yun; Pike, Suzette; Pang, Qishen

    2010-02-01

    An elevated level of nucleophosmin (NPM) is often found in actively proliferative cells including human tumors. To identify the regulatory role for NPM phosphorylation in proliferation and cell cycle control, a series of mutants targeting the consensus cyclin-dependent kinase (CDK) phosphorylation sites was created to mimic or abrogate either single-site or multi-site phosphorylation. Simultaneous inactivation of two CDK phosphorylation sites at Ser10 and Ser70 (NPM-AA) induced G(2)/M cell cycle arrest, phosphorylation of Cdk1 at Tyr15 (Cdc2(Tyr15)) and increased cytoplasmic accumulation of Cdc25C. Strikingly, stress-induced Cdk1(Tyr15) and Cdc25C sequestration was suppressed by expression of a phosphomimetic NPM mutant created on the same CDK sites (S10E/S70E, NPM-EE). Further analysis revealed that phosphorylation of NPM at both Ser10 and Ser70 was required for proper interaction between Cdk1 and Cdc25C. Moreover, NPM-EE directly bound to Cdc25C and prevented phosphorylation of Cdc25C at Ser216 during mitosis. Finally, NPM-EE overrided stress-induced G(2)/M arrest and increased leukemia blasts in a NOD/SCID xenograft model. Thus, these findings reveal a novel function of NPM on regulation of cell cycle progression, in which phosphorylation of NPM controls cell cycle progression at G(2)/M transition through modulation of Cdk1 and Cdc25C activities.

  8. Three-dimensional spatial cognition: information in the vertical dimension overrides information from the horizontal.

    Science.gov (United States)

    Holbrook, Robert I; Burt de Perera, Theresa

    2011-07-01

    Fish live in three-dimensional environments, through which they swim with three translational and three rotational degrees of freedom. Navigating through such environments is recognised as a difficult problem, yet fish, and other animals that swim and fly, achieve this regularly. Despite this, the vast majority of research has considered how animals navigate horizontally from place to place and has ignored the vertical component. Here, we test the importance of the vertical axis of space for fish solving a three-dimensional spatial cognition task. We trained banded tetras (Astyanax fasciatus) to learn the route towards a goal in a rotating Y-maze in which the arms led either up and left or down and right in an environment that allowed access to visual landmarks providing horizontal and vertical information. Our results revealed that the landmarks increased navigational efficiency during training. However, these landmarks were ignored when the horizontal and vertical components were placed in conflict with each other by rotating the maze 90° during testing. From this surprising result, we conclude that the cues that are present in the vertical axis (presumably hydrostatic pressure) override landmark cues that have been shown to be salient in experiments that only consider the horizontal component of space.

  9. Geometric figure-ground cues override standard depth from accretion-deletion.

    Science.gov (United States)

    Tanrikulu, Ömer Daglar; Froyen, Vicky; Feldman, Jacob; Singh, Manish

    2016-01-01

    Accretion-deletion is widely considered a decisive cue to surface depth ordering, with the accreting or deleting surface interpreted as behind an adjoining surface. However, Froyen, Feldman, and Singh (2013) have shown that when accretion-deletion occurs on both sides of a contour, accreting-deleting regions can also be perceived as in front and as self-occluding due to rotation in three dimensions. In this study we ask whether geometric figure-ground cues can override the traditional "depth from accretion-deletion" interpretation even when accretion-deletion takes place only on one side of a contour. We used two tasks: a relative-depth task (front/back), and a motion-classification task (translation/rotation). We conducted two experiments, in which texture in only one set of alternating regions was moving; the other set was static. Contrary to the traditional interpretation of accretion-deletion, the moving convex and symmetric regions were perceived as figural and rotating in three dimensions in roughly half of the trials. In the second experiment, giving different motion directions to the moving regions (thereby weakening motion-based grouping) further weakened the traditional accretion-deletion interpretation. Our results show that the standard "depth from accretion-deletion" interpretation is overridden by static geometric cues to figure-ground. Overall, the results demonstrate a rich interaction between accretion-deletion, figure-ground, and structure from motion that is not captured by existing models of depth from motion.

  10. Oscillations in motor unit discharge are reflected in the low-frequency component of rectified surface EMG and the rate of change in force.

    Science.gov (United States)

    Yoshitake, Yasuhide; Shinohara, Minoru

    2013-11-01

    Common drive to a motor unit (MU) pool manifests as low-frequency oscillations in MU discharge rate, producing fluctuations in muscle force. The aim of the study was to examine the temporal correlation between instantaneous MU discharge rate and rectified EMG in low frequencies. Additionally, we attempted to examine whether there is a temporal correlation between the low-frequency oscillations in MU discharge rate and the first derivative of force (dF/dt). Healthy young subjects produced steady submaximal force with their right finger as a single task or while maintaining a pinch-grip force with the left hand as a dual task. Surface EMG and fine-wire MU potentials were recorded from the first dorsal interosseous muscle in the right hand. Surface EMG was band-pass filtered (5-1,000 Hz) and full-wave rectified. Rectified surface EMG and the instantaneous discharge rate of MUs were smoothed by a Hann-window of 400 ms duration (equivalent to 2 Hz low-pass filtering). In each of the identified MUs, the smoothed MU discharge rate was positively correlated with the rectified-and-smoothed EMG as confirmed by the distinct peak in cross-correlation function with greater values in the dual task compared with the single task. Additionally, the smoothed MU discharge rate was temporally correlated with dF/dt more than with force and with rectified-and-smoothed EMG. The results indicated that the low-frequency component of rectified surface EMG and the first derivative of force provide temporal information on the low-frequency oscillations in the MU discharge rate.

  11. Similar changes in muscle fiber phenotype with differentiated consequences for rate of force development: endurance versus resistance training.

    Science.gov (United States)

    Farup, Jean; Sørensen, Henrik; Kjølhede, Tue

    2014-04-01

    Resistance training has been shown to positively affect the rate of force development (RFD) whereas there is currently no data on the effect of endurance training on RFD. Subjects completed ten weeks of either resistance training (RT, n=7) or endurance cycling (END, n=7). Pre and post measurements included biopsies obtained from m. vastus lateralis to quantify fiber phenotype and fiber area and isokinetic dynamometer tests to quantify maximal torque (Nm) and RFD (Nm/s) at 0-30, 0-50, 0-100 and 0-200ms during maximal isometric contraction for both knee extensors and flexors. Both groups increased the area percentage of type IIa fibers (p<.01) and decreased the area percentage of type IIx fibers (p=.05), whereas only RT increased fiber size (p<.05). RT significantly increased eccentric, concentric and isometric strength for both knee extensors and flexors, whereas END did not. RT increased 200ms RFD (p<.01) in knee flexor RFD and a tendency towards an increase at 100ms (p<.1), whereas tendencies towards decreases were observed for the END group at 30, 50 and 100ms (p<.1), resulting in RT having a higher RFD than END at post (p<.01). In conclusion, resistance training may be very important for maintaining RFD, whereas endurance training may negatively impact RFD.

  12. The rate of force development obtained at early contraction phase is not influenced by active static stretching.

    Science.gov (United States)

    Morais de Oliveira, André L; Greco, Camila Coelho; Molina, Renato; Denadai, Benedito S

    2012-08-01

    The objective of this study was to investigate the influence of active static stretching on the maximal isometric muscle strength (maximal voluntary contraction [MVC]) and rate of force development (RFD) determined within time intervals of 30, 50, 100, and 200 milliseconds relative to the onset of muscle contraction. Fifteen men (aged 21.3 ± 2.4 years) were submitted on different days to the following tests: (a) familiarization session to the isokinetic dynamometer; (b) 2 maximal isometric contractions for knee extensors in the isokinetic dynamometer to determine MVC and RFD (control); and (c) 2 active static stretching exercises for the dominant leg extensors (10 × 30 seconds for each exercise with a 20-second rest interval between bouts). After stretching, the isokinetic test was repeated (poststretching). Conditions 2 and 3 were performed in random order. The RFD was considered as the mean slope of the moment-time curve at time intervals of 0-30, 0-50, 0-100; 0-150; and 0200 milliseconds relative to the onset of muscle contraction. The MVC was reduced after stretching (285 ± 59 vs. 271 ± 56 N · m, p 0.05). However, the RFD measured at intervals of 0-150 and 0-200 milliseconds was significantly lower after stretching (p < 0.01). It can be concluded that explosive muscular actions of a very short duration (<100 milliseconds) seem less affected by active static stretching when compared with actions using maximal muscle strength.

  13. Effect of Five-Finger Shoes on Vertical Ground Reaction Force Loading Rates and Perceived Comfort during the Stance Phase of the Running

    Directory of Open Access Journals (Sweden)

    Seyede Zeynab Hoseini

    2016-06-01

    Full Text Available Objective:  Increased vertical ground reaction force loading rates and lack of comfort footwear in the early stance phase can increase the risk of overuse injuries. The purpose of this study was to investigate the effect of Five-finger shoes on vertical ground reaction force loading rate and perceived comfort during the stance phase of running. Methods: 15 male students (aged 24 ± 5/24 years, weight 75/8 ± 4/61 kg, height 178/6 ± 6/64 cm were selected. Subjects were asked to run over a force plate, in control shoe, five finger shoe and barefoot conditions. Loading rate using the slope of the vertical reaction force and perceived comfort were determined using a visual analogue scale. One factor repeated measures ANOVA was used to test the loading rate hypothesis and Paired t-tests was used to test the meaningfulness of perceived comfort (P<0/05. Results: The effect of shoes on loading rate was found to be not significant (P=0.1. However, comfort of control shoes increased by 10. 92% as compared to that of five-finger shoes (P=0.001.  Conclusion: The loading rate of five-finger shoes is the same as that of barefoot during running; however, as subjects did not perceive them as comfortable as regular shoes are five-finger shoes cannot be advised as a desirable choice in exercises.

  14. Age, marital satisfaction, and optimism as predictors of positive sentiment override in middle-aged and older married couples.

    Science.gov (United States)

    Story, T Nathan; Berg, Cynthia A; Smith, Timothy W; Beveridge, Ryan; Henry, Nancy J M; Pearce, Gale

    2007-12-01

    This study examined whether positive sentiment override (greater positive appraisal of spouse's affiliative behavior than is warranted by observed behavior) occurred more frequently in older compared with middle-aged married couples and whether age differences were mediated by older adults' greater marital satisfaction when controlling for optimism. Participants included 270 middle-aged (40-50 years old) and older (60-70 years old) couples who discussed a marital disagreement and completed an errand task. Couples provided appraisals of their spouse's affiliation, and the authors coded affiliative interactions using the structural analysis of social behavior. Hierarchical multivariate linear modeling indicated that older husbands and wives viewed their spouse's behavior as more positive during disagreement interactions than did independent observers; in the errand task, only older wives demonstrated positive sentiment override. Age differences in positive sentiment override were mediated by marital satisfaction, even when controlling for optimism. The results are consistent with theories of emotion regulation, such as socioemotional selectivity theory, that suggest that older adults are biased toward the positive aspects of close relationships.

  15. The effects of the overriding plate thermal state on the slab dip in an ocean-continent subduction system

    CERN Document Server

    Roda, Manuel; Spalla, Maria Iole; 10.1016/j.crte.2011.01.005

    2011-01-01

    To evaluate the effects of variations in the thermal state of the overriding plate on the slab dip in an ocean-continent subduction system, a 2-D finite element thermo-mechanical model was implemented. The lithosphere base was located at the depth of the 1600 K isotherm. Numerical simulations were performed while taking into account four different initial thicknesses for the oceanic lithosphere (60, 80, 95 and 110 km) and five different thicknesses of the overriding plate, as compared in terms of the continental-oceanic plate thickness ratio (100, 120, 140, 160 and 200% of the oceanic lithosphere thickness). The results of numerical modeling indicate that a high variability of the subducting plate geometry occurs for an oceanic lithosphere thickness ranging from 60 to 80 km, while the variability decreases where the oceanic plates are thicker (95 and 110 km). Furthermore, the slab dip strongly depends on the thermal state of the overriding plate, and, in particular, the slab dip decreases with the increase in...

  16. Eutrophication effects on greenhouse gas fluxes from shallow-lake mesocosms override those of climate warming.

    Science.gov (United States)

    Davidson, Thomas A; Audet, Joachim; Svenning, Jens-Christian; Lauridsen, Torben L; Søndergaard, Martin; Landkildehus, Frank; Larsen, Søren E; Jeppesen, Erik

    2015-12-01

    Fresh waters make a disproportionately large contribution to greenhouse gas (GHG) emissions, with shallow lakes being particular hot spots. Given their global prevalence, how GHG fluxes from shallow lakes are altered by climate change may have profound implications for the global carbon cycle. Empirical evidence for the temperature dependence of the processes controlling GHG production in natural systems is largely based on the correlation between seasonal temperature variation and seasonal change in GHG fluxes. However, ecosystem-level GHG fluxes could be influenced by factors, which while varying seasonally with temperature are actually either indirectly related (e.g. primary producer biomass) or largely unrelated to temperature, for instance nutrient loading. Here, we present results from the longest running shallow-lake mesocosm experiment which demonstrate that nutrient concentrations override temperature as a control of both the total and individual GHG flux. Furthermore, testing for temperature treatment effects at low and high nutrient levels separately showed only one, rather weak, positive effect of temperature (CH4 flux at high nutrients). In contrast, at low nutrients, the CO2 efflux was lower in the elevated temperature treatments, with no significant effect on CH4 or N2 O fluxes. Further analysis identified possible indirect effects of temperature treatment. For example, at low nutrient levels, increased macrophyte abundance was associated with significantly reduced fluxes of both CH4 and CO2 for both total annual flux and monthly observation data. As macrophyte abundance was positively related to temperature treatment, this suggests the possibility of indirect temperature effects, via macrophyte abundance, on CH4 and CO2 flux. These findings indicate that fluxes of GHGs from shallow lakes may be controlled more by factors indirectly related to temperature, in this case nutrient concentration and the abundance of primary producers. Thus, at ecosystem

  17. Nicotine overrides DNA damage-induced G1/S restriction in lung cells.

    Directory of Open Access Journals (Sweden)

    Takashi Nishioka

    Full Text Available As an addictive substance, nicotine has been suggested to facilitate pro-survival activities (such as anchorage-independent growth or angiogenesis and the establishment of drug resistance to anticancer therapy. Tobacco smoking consists of a variety of carcinogens [such as benzopyrene (BP and nitrosamine derivatives] that are able to cause DNA double strand breaks. However, the effect of nicotine on DNA damage-induced checkpoint response induced by genotoxins remains unknown. In this study, we investigated the events occurred during G(1 arrest induced by γ-radiation or BP in nicotine-treated murine or human lung epithelial cells. DNA synthesis was rapidly inhibited after exposure to γ-radiation or BP treatment, accompanied with the activation of DNA damage checkpoint. When these cells were co-treated with nicotine, the growth restriction was compromised, manifested by upregulation of cyclin D and A, and attenuation of Chk2 phosphorylation. Knockdown of cyclin D or Chk2 by the siRNAs blocked nicotine-mediated effect on DNA damage checkpoint activation. However, nicotine treatment appeared to play no role in nocodazole-induced mitotic checkpoint activation. Overall, our study presented a novel observation, in which nicotine is able to override DNA damage checkpoint activated by tobacco-related carcinogen BP or γ-irradiation. The results not only indicates the potentially important role of nicotine in facilitating the establishment of genetic instability to promote lung tumorigenesis, but also warrants a dismal prognosis for cancer patients who are smokers, heavily exposed second-hand smokers or nicotine users.

  18. Geometric figure–ground cues override standard depth from accretion-deletion

    Science.gov (United States)

    Tanrıkulu, Ömer Dağlar; Froyen, Vicky; Feldman, Jacob; Singh, Manish

    2016-01-01

    Accretion-deletion is widely considered a decisive cue to surface depth ordering, with the accreting or deleting surface interpreted as behind an adjoining surface. However, Froyen, Feldman, and Singh (2013) have shown that when accretion-deletion occurs on both sides of a contour, accreting-deleting regions can also be perceived as in front and as self-occluding due to rotation in three dimensions. In this study we ask whether geometric figure–ground cues can override the traditional “depth from accretion-deletion” interpretation even when accretion-deletion takes place only on one side of a contour. We used two tasks: a relative-depth task (front/back), and a motion-classification task (translation/rotation). We conducted two experiments, in which texture in only one set of alternating regions was moving; the other set was static. Contrary to the traditional interpretation of accretion-deletion, the moving convex and symmetric regions were perceived as figural and rotating in three dimensions in roughly half of the trials. In the second experiment, giving different motion directions to the moving regions (thereby weakening motion-based grouping) further weakened the traditional accretion-deletion interpretation. Our results show that the standard “depth from accretion-deletion” interpretation is overridden by static geometric cues to figure–ground. Overall, the results demonstrate a rich interaction between accretion-deletion, figure–ground, and structure from motion that is not captured by existing models of depth from motion. PMID:26982528

  19. Health research and systems' governance are at risk: should the right to data protection override health?

    Science.gov (United States)

    Di Iorio, C T; Carinci, F; Oderkirk, J

    2014-07-01

    The European Union (EU) Data Protection Regulation will have profound implications for public health, health services research and statistics in Europe. The EU Commission's Proposal was a breakthrough in balancing privacy rights and rights to health and healthcare. The European Parliament, however, has proposed extensive amendments. This paper reviews the amendments proposed by the European Parliament Committee on Civil Liberties, Justice and Home Affairs and their implications for health research and statistics. The amendments eliminate most innovations brought by the Proposal. Notably, derogation to the general prohibition of processing sensitive data shall be allowed for public interests such as the management of healthcare services,but not health research, monitoring, surveillance and governance. The processing of personal health data for historical, statistical or scientific purposes shall be allowed only with the consent of the data subject or if the processing serves an exceptionally high public interest, cannot be performed otherwise and is legally authorised. Research, be it academic, government,corporate or market research, falls under the same rule.The proposed amendments will make difficult or render impossible research and statistics involving the linkage and analysis of the wealth of data from clinical,administrative, insurance and survey sources, which have contributed to improving health outcomes and health systems performance and governance; and may illegitimise efforts that have been made in some European countries to enable privacy-respectful data use for research and statistical purposes. If the amendments stand as written, the right to privacy is likely to override the right to health and healthcare in Europe.

  20. Allopregnanolone reduces immobility in the forced swimming test and increases the firing rate of lateral septal neurons through actions on the GABAA receptor in the rat.

    Science.gov (United States)

    Rodrìguez-Landa, Juan Francisco; Contreras, Carlos M; Bernal-Morales, Blandina; Gutièrrez-Garcìa, Ana G; Saavedra, Margarita

    2007-01-01

    Since allopregnanolone reduces the total time of immobility in rats submitted to the forced swimming test, we decided to explore whether this neuroactive steroid shares other antidepressant-like actions, such as increasing the neuronal firing rate in the lateral septal nucleus (LSN). In order to discard the influence of the oestrous cycle on immobility and on the firing rate of LSN neurons, all Wistar rats used in the study underwent ovariectomy before treatments. A group of rats received different doses of allopregnanolone (0.5, 1.0, 2.0 and 3.0 mg/kg, i.p.) 1 hour before being forced to swim in order to identify the minimum effective dose diminishing immobility. None of the tested doses of allopregnanolone produced significant changes in motor activity in the open-field test. The minimum dose of allopregnanolone producing a significant reduction in the total time of immobility (pimmobility (pimmobility in the forced swimming test (1.0 mg/kg) significantly (p immobility and LSN firing rate. In conclusion, allopregnanolone produces an antidepressant-like effect in the forced swimming test, associated with an increase in the LSN neuronal firing rate, seemingly mediated by the GABAA receptor.

  1. Ras Transformation Overrides a Proliferation Defect Induced by Tpm3.1 Knockout.

    Science.gov (United States)

    Coombes, Jason D; Schevzov, Galina; Kan, Chin-Yi; Petti, Carlotta; Maritz, Michelle F; Whittaker, Shane; Mackenzie, Karen L; Gunning, Peter W

    2015-12-01

    Extensive re-organisation of the actin cytoskeleton and changes in the expression of its binding proteins is a characteristic feature of cancer cells. Previously we have shown that the tropomyosin isoform Tpm3.1, an integral component of the actin cytoskeleton in tumor cells, is required for tumor cell survival. Our objective was to determine whether cancer cells devoid of Tpm3.1 would evade the tumorgenic effects induced by H-Ras transformation. The tropomyosin isoform (Tpm) expression profile of a range of cancer cell lines (21) demonstrates that Tpm3.1 is one of the most broadly expressed Tpm isoform. Consequently, the contribution of Tpm3.1 to the transformation process was functionally evaluated. Primary embryonic fibroblasts isolated from wild type (WT) and Tpm3.1 knockout (KO) mice were transduced with retroviral vectors expressing SV40 large T antigen and an oncogenic allele of the H-Ras gene, H-RasV12, to generate immortalized and transformed WT and KO MEFs respectively. We show that Tpm3.1 is required for growth factor-independent proliferation in the SV40 large T antigen immortalized MEFs, but this requirement is overcome by H-Ras transformation. Consistent with those findings, we found that Tpm3.1 was not required for anchorage independent growth or growth of H-Ras-driven tumors in a mouse model. Finally, we show that pERK and Importin 7 protein interactions are significantly decreased in the SV40 large T antigen immortalized KO MEFs but not in the H-Ras transformed KO cells, relative to control MEFs. The data demonstrate that H-Ras transformation overrides a requirement for Tpm3.1 in growth factor-independent proliferation of immortalized MEFs. We propose that in the SV40 large T antigen immortalized MEFs, Tpm3.1 is partly responsible for the efficient interaction between pERK and Imp7 resulting in cell proliferation, but this is overidden by Ras transformation.

  2. Effect of environmental forcing on the biomass, production and growth rate of size-fractionated phytoplankton in the central Atlantic Ocean

    Science.gov (United States)

    Huete-Ortega, María; Calvo-Díaz, Alejandra; Graña, Rocío; Mouriño-Carballido, Beatriz; Marañón, Emilio

    2011-11-01

    To ascertain the response of phytoplankton size classes to changes in environmental forcing, we determined size-fractionated biomass, carbon fixation and growth (production/biomass) rates in surface waters along the central Atlantic Ocean (26°N-5°S). As a result of the enhanced input of nutrients into the euphotic layer and the higher water column stability found at the equatorial upwelling, we observed increases not only in phytoplankton biomass and primary production, but also in turnover rates, suggesting nutrient limitation of phytoplankton physiology in the oligotrophic central Atlantic. The phytoplankton groups analysed (pico-, small nano-, large nano- and micro-phytoplankton) showed different responses to the equatorial environmental forcing, in terms of carbon biomass, primary production and growth rate. Large nano- and micro-phytoplankton consistently showed higher growth rates and carbon fixation to chl a ratios than smaller phytoplankton. We observed a higher stimulating effect of increased nitrate supply on the small phytoplankton growth rates. This observation can be explained by the dynamics of the equatorial upwelling, where the continuous but small nutrient input into the euphotic layer provide a competitive advantage for smaller cells adapted to oligotrophic conditions. The size-fractionated approach shown here reveals important group-specific differences in the response to environmental forcing, which cannot be appreciated in bulk measurements of the whole community.

  3. The Weber-curve pitfall : effects of a forced introduction on reporting rates and reported adverse reaction profiles

    NARCIS (Netherlands)

    de Graaf, Linda; Fabius, Mariette A; Diemont, Willem L; van Puijenbroek, Eugène P

    2003-01-01

    BACKGROUND: In May 1999 Losec MUPS (MUPS) were granted a marketing authorization in the Netherlands, followed by the withdrawal of the Losec capsules (capsules) in September 1999. Both formulations contain omeprazole as active substance. This forced switch resulted in a large number of spontaneous r

  4. The role of the Denali fault, slab geometry, and rheology in the deformation of the overriding plate in Alaska

    Science.gov (United States)

    Jadamec, M.; Billen, M. I.; Roeske, S.

    2010-12-01

    Deformation of the North American plate in southern Alaska is characterized by uplift along the subducting plate boundary as well as a region of localized uplift in the Alaskan Range more than 500 km from the plate boundary. This interior plate deformation is spatially coincident with both the Denali Fault zone and the shallow slab in the subsurface. Whether the Denali Fault zone plays a role in localizing uplift in this region is debated and the affect of the change in slab dip on deformation of the overriding plate is also not well understood. We present 3D regional geodynamic models of the North American-Pacific plate boundary corner in southern Alaska that include the Denali fault zone modeled as a lithospheric-scale shear zone. The models include the subducting plate, overriding plate, and underlying mantle to 1500 km depth. The geometry of the subducting plate, defined from Wadati-Benioff zone seismicity and tomography, varies along the length of the Aleutian trench forming a flat slab beneath south central Alaska. The models are run with the finite-element code CitcomCU, modified to include a composite rheology (both Newtonian and non-Newtonian viscosity, as well as a depth-dependent yield stress). The models suggest the flat slab geometry beneath south central Alaska controls several first order deformation features in the overriding plate, including subsidence in the Cook Inlet Basin. To reproduce the localized uplift observed in the central Alaska Range, the models require a non-Newtonian rheology and a localized lithospheric weak zone representative of the Denali Fault, as well as the shallow slab geometry. Models with only a Newtonian viscosity do not reproduce the observed uplift, even when a localized lithospheric weak zone representative of the Denali Fault is included, indicating the importance of including the non-Newtonian mantle rheology for accurately modeling surface plate deformation.

  5. Implementation of the forced answering option within online surveys: Do higher item response rates come at the expense of participation and answer quality?

    Directory of Open Access Journals (Sweden)

    Décieux Jean Philippe

    2015-01-01

    Full Text Available Online surveys have become a popular method for data gathering for many reasons, including low costs and the ability to collect data rapidly. However, online data collection is often conducted without adequate attention to implementation details. One example is the frequent use of the forced answering option, which forces the respondent to answer each question in order to proceed through the questionnaire. The avoidance of missing data is often the idea behind the use of the forced answering option. However, we suggest that the costs of a reactance effect in terms of quality reduction and unit nonresponse may be high because respondents typically have plausible reasons for not answering questions. The objective of the study reported in this paper was to test the influence of forced answering on dropout rates and data quality. The results show that requiring participants answer every question increases dropout rates and decreases quality of answers. Our findings suggest that the desire for a complete data set has to be balanced against the consequences of reduced data quality.

  6. Item Vetoes and Attempts to Override Them in Multiparty Legislatures Vetos parciales e intentos de insistencia en legislaturas multipartidistas

    Directory of Open Access Journals (Sweden)

    Valeria Palanza

    2013-01-01

    Full Text Available This paper analyzes the dynamics of vetoes and veto overrides in the context of a multiparty legislature using an original dataset from the period 1983–2007 in Argentina. We argue that the President can use an “item” or “partial” veto to selectively delete articles, while keeping enough distributive goods in the bill to break up the coalition responsible for its passage, thereby eliminating support for an override. Our research reveals that total vetoes – which affect all legislators equally – are more likely to be overridden than partial vetoes. Contradicting the received wisdom that in multiparty legislatures override attempts are more likely under a divided government, we find that override attempts are more likely in plurality governments. We use case analyses to illustrate the main arguments developed in this paper.El trabajo estudia las dinámicas desatadas por la práctica del veto presidencial e insistencias del congreso, en el contexto de legislaturas multipartidarias, a través del análisis de una base de datos original que abarca el período 1983-2007 en Argentina. El trabajo argumenta que el presidente puede usar el veto parcial para quitar del texto, en forma selectiva, artículos puntuales, dejando al mismo tiempo en el texto bienes distributivos suficientes como para romper la coalición responsable de la aprobación del proyecto, de manera tal de eliminar la posibilidad de una insistencia. La investigación revela que los vetos totales, que afectan por igual a todos los legisladores, son más factibles de ser insistidos que los vetos parciales. En contra de lo sostenido al momento acerca de que en legislaturas multipartidarias los intentos de insistencia son más factibles bajo gobierno dividido, este trabajo encuentra que son más factibles cuando el gobierno cuenta con al menos una pluralidad en una de las cámaras. Además del análisis cuantitativo, presentamos estudios de casos para ilustrar los argumentos

  7. Breath-hold after forced expiration before removal of the biopsy needle decreased the rate of pneumothorax in CT-guided transthoracic lung biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Min, Lingfeng; Xu, Xingxiang [Subei People' s Hospital of Jiangsu Province, Clinical Medical School of Yangzhou University, Yangzhou 225001, Jiangsu (China); Song, Yong [Jinling Hospital, Nanjing University School of Medical, Nanjing 210002, Jiangsu (China); Issahar, Ben-Dov [Pulmonary Institute, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Wu, Jingtao; Zhang, Le; Huang, Qian [Subei People' s Hospital of Jiangsu Province, Clinical Medical School of Yangzhou University, Yangzhou 225001, Jiangsu (China); Chen, Mingxiang, E-mail: chenmx1129@126.com [Subei People' s Hospital of Jiangsu Province, Clinical Medical School of Yangzhou University, Yangzhou 225001, Jiangsu (China)

    2013-01-15

    Purpose: To assess the effect of a breath-hold after forced expiration on the rate of pneumothorax after computed tomography (CT)-guided transthoracic needle biopsy of pulmonary lesions. Materials and methods: Between January 2008 and December 2011, percutaneous CT-guided lung biopsy was performed in 440 patients. Two hundred and twenty-one biopsies were performed without (control group) and two hundred and nineteen biopsies were performed with (study group) the study maneuver – a breath-hold after forced expiratory approach. Multivariate analysis was performed between groups for risk factors for pneumothorax, including patient demographics, lesion characteristics, and biopsy technique. Results: A reduced number of pneumothoraces (18 [8.2%] vs 35 [15.8%]; P = 0.014) but no significant difference in rate of drainage catheter insertions (2 [0.9%] vs (4 [1.8%]; P = 0.418) were noted in the study group as compared with the control group. By logistic regression analysis, three factors significantly and independently affected the risk for pneumothorax including lesion size (transverse and longitudinal diameter), distance from pleura and utilizing or avoiding the breath-hold after deep expiration maneuver. Conclusion: Breath-holding after forced expiration before removal of the biopsy needle during the percutaneous CT-guided transthoracic lung biopsy almost halved the rate of overall pneumothorax. Small lesion size (longitudinal diameter) and the distance from pleura were also predictors of pneumothorax in our study.

  8. 27.3-day and Average 13.6-day Periodic Oscillations in the Earth's Rotation Rate and Atmospheric Pressure Fields Due to Celestial Gravitation Forcing

    Institute of Scientific and Technical Information of China (English)

    LI Guoqing; ZONG Haifeng; ZHANG Qingyun

    2011-01-01

    Variation in length of day of the Earth (LOD equivalent to the Earth's rotation rate) versus change in atmospheric geopotential height fields and astronomical parameters were analyzed for the years 1962-2006.This revealed that there is a 27.3-day and an average 13.6-day periodic oscillation in LOD and atmospheric pressure fields following lunar revolution around the Earth. Accompanying the alternating change in celestial gravitation forcing on the Earth and its atmosphere, the Earth's LOD changes from minimum to maximum,then to minimum. and the atmospheric geopotential height fields in the tropics oscillate from low to high,then to low. The 27.3-day and average 13.6-day periodic atmospheric oscillation in the tropics is proposed to be a type of strong atmospheric tide, excited by celestial gravitation forcing. A formula for a Tidal Index was derived to estimate the strength of the celestial gravitation forcing, and a high degree of correlation was found between the Tidal Index determined by astronomical parameters, LOD, and atmospheric geopotential height. The reason for the atmospheric tide is periodic departure of the lunar orbit from the celestial equator during lunar revolution around the Earth. The alternating asymmetric change in celestial gravitation forcing on the Earth and its atmosphere produces a "modulation" to the change in the Earth's LOD and atmospheric pressure fields.

  9. Contact behavior analysis of elastomeric x-ring under uniform squeeze rate and internal pressure before and after forcing-out using the photoelastic experimental hybrid method

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Alunda Ouma [Dedan Kimathi University of Technology, Nyeri (Kenya); Hawong, Jai Sug; Dong, Bai [Yeungnam University, Gyeongsan (Korea, Republic of); Shin, Dong Chul [Koje College, Geoje (Korea, Republic of)

    2015-05-15

    Many different types of elastomeric rings have been developed to suit various needs in industry. The X-ring was introduced as a result of the limitations of O-rings that twist, especially during dynamic application. A better understanding of the behavior and the stress distribution of the X-ring under a uniform squeeze rate and internal pressure is needed. We analyzed the contact stresses and internal stresses developed in an X-ring before and after forcing-out by using the photoelastic experimental hybrid method, ascertained the packing ability of an X-ring, and studied the failure criterion of an X-ring under uniform squeeze rate and internal pressure. Forcing-out in the X-ring occurred when the internal pressure was 3.92 MPa. After forcing-out, at an internal pressure of 5.88 MPa, the two lobes on the upper contact surface merged one contact side of the upper side immensely. Even after extrusion of the X-ring, the X-ring can be used to effectively contain the fluid. This is because the effects of extrusion on the X-ring affected the stress distribution of only two lobes close to the assembly gap and the two lobes are merge into one lobe. In addition, our experimental results show that the maximum shear failure criterion is suitable for the prediction of failure in X-ring seals.

  10. The Rey Auditory Verbal Learning Test forced-choice recognition task: Base-rate data and norms.

    Science.gov (United States)

    Poreh, Amir; Bezdicek, Ondrej; Korobkova, Irina; Levin, Jennifer B; Dines, Philipp

    2016-01-01

    The present study describes a novel Forced-Choice Response (FCR) index for detecting poor effort on the Rey Auditory Verbal Learning Test (RAVLT). This retrospective study analyzes the performance of 4 groups on the new index: clinically referred patients with suspected dementia, forensic patients identified as not exhibiting adequate effort on other measures of response bias, students who simulated poor effort, and a large normative sample collected in the Gulf State of Oman. Using sensitivity and specificity analyses, the study shows that much like the California Verbal Learning Test-Second Edition FCR index, the RAVLT FCR index misses a proportion of individuals with inadequate effort (low sensitivity), but those who fail this measure are highly likely to be exhibiting poor effort (high specificity). The limitations and benefits of utilizing the RAVLT FCR index in clinical practice are discussed.

  11. Bouncing on Mars and the Moon-the role of gravity on neuromuscular control: correlation of muscle activity and rate of force development.

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Krause, Anne; Gollhofer, Albert

    2016-11-01

    On our astronomical neighbors Mars and the Moon, bouncing movements are the preferred locomotor techniques. During bouncing, the stretch-shortening cycle describes the muscular activation pattern. This study aimed to identify gravity-dependent changes in kinematic and neuromuscular characteristics in the stretch-shortening cycle. Hence, neuromuscular control of limb muscles as well as correlations between the muscles' pre-activation, reflex components, and force output were assessed in lunar, Martian, and Earth gravity. During parabolic flights, peak force (Fmax), ground-contact-time, rate of force development (RFD), height, and impulse were measured. Electromyographic (EMG) activities in the m. soleus (SOL) and gastrocnemius medialis (GM) were assessed before (PRE) and during bounces for the reflex phases short-, medium-, and long-latency response (SLR, MLR, LLR). With gradually decreasing gravitation, Fmax, RFD, and impulse were reduced, whereas ground-contact time and height increased. Concomitantly, EMG_GM decreased for PRE, SLR, MLR, and LLR, and in EMG_SOL in SLR, MLR, and LLR. For SLR and MLR, Fmax and RFD were positively correlated to EMG_SOL. For PRE and LLR, RFD and Fmax were positively correlated to EMG_GM. Findings emphasize that biomechanically relevant kinematic adaptations in response to gravity variation were accompanied by muscle- and phase-specific modulations in neural control. Gravitational variation is anticipated and compensated for by gravity-adjusted muscle activities. Importantly, the pre-activation and reflex phases were differently affected: in SLR and MLR, SOL is assumed to contribute to the decline in force output with a decreasing load, and, complementary in PRE and LLR, GM seems to be of major importance for force generation.

  12. To what extent do financial strain and labour force status explain social class inequalities in self-rated health? Analysis of 20 countries in the European Social Survey.

    Directory of Open Access Journals (Sweden)

    Richard J Shaw

    Full Text Available Nordic countries do not have the smallest health inequalities despite egalitarian social policies. A possible explanation for this is that drivers of class differences in health such as financial strain and labour force status remain socially patterned in Nordic countries.Our analyses used data for working age (25-59 men (n = 48,249 and women (n = 52,654 for 20 countries from five rounds (2002-2010 of the European Social Survey. The outcome was self-rated health in 5 categories. Stratified by gender we used fixed effects linear regression models and marginal standardisation to instigate how countries varied in the degree to which class inequalities were attenuated by financial strain and labour force status.Before adjustment, Nordic countries had large inequalities in self-rated health relative to other European countries. For example the regression coefficient for the difference in health between working class and professional men living in Norway was 0.34 (95% CI 0.26 to 0.42, while the comparable figure for Spain was 0.15 (95% CI 0.08 to 0.22. Adjusting for financial strain and labour force status led to attenuation of health inequalities in all countries. However, unlike some countries such as Spain, where after adjustment the regression coefficient for working class men was only 0.02 (95% CI -0.05 to 0.10, health inequalities persisted after adjustment for Nordic countries. For Norway the adjusted coefficient was 0.17 (95% CI 0.10 to 0.25. Results for women and men were similar. However, in comparison to men, class inequalities tended to be stronger for women and more persistent after adjustment.Adjusting for financial security and labour force status attenuates a high proportion of health inequalities in some counties, particularly Southern European countries, but attenuation in Nordic countries was modest and did not improve their relative position.

  13. Elevated rates of force development and MgATP binding in F764L and S532P myosin mutations causing dilated cardiomyopathy.

    Science.gov (United States)

    Palmer, Bradley M; Schmitt, Joachim P; Seidman, Christine E; Seidman, J G; Wang, Yuan; Bell, Stephen P; Lewinter, Martin M; Maughan, David W

    2013-04-01

    Dilated cardiomyopathy (DCM) is a disease characterized by dilation of the ventricular chambers and reduced contractile function. We examined the contractile performance of chemically-skinned ventricular strips from two heterozygous murine models of DCM-causing missense mutations of myosin, F764L/+ and S532P/+, in an α-myosin heavy chain (MyHC) background. In Ca(2+)-activated skinned myocardial strips, the maximum developed tension in F764L/+ was only ~50% that of litter-mate controls (+/+). The F764L/+ also exhibited significantly reduced rigor stiffness, loaded shortening velocity and power output. Corresponding indices for S532P/+ strips were not different from controls. Manipulation of MgATP concentration in conjunction with measures of viscoelasticity, which provides estimates of myosin detachment rate 2πc, allowed us to probe the molecular basis of changes in crossbridge kinetics that occur with the myosin mutations. By examining the response of detachment rate to varying MgATP we found the rate of MgADP release was unaffected by the myosin mutations. However, MgATP binding rate was higher in the DCM groups compared to controls (422±109mM(-1)·s(-1) in F764L/+, 483±74mM(-1)·s(-1) in S532P/+ and 303±18mM(-1)·s(-1) in +/+). In addition, the rate constant of force development, 2πb, was significantly higher in DCM groups compared to controls (at 5mM MgATP: 36.9±4.9s(-1) in F764L/+, 32.9±4.5s(-1) in S532P/+ and 18.2±1.7s(-1) in +/+). These results suggest that elevated rates of force development and MgATP binding are features of cardiac myofilament function that underlie the development of DCM.

  14. Effects of pressure, oxygen concentration, and forced convection on flame spread rate of Plexiglas, Nylon and Teflon

    Science.gov (United States)

    Notardonato, J. J.; Burkhardt, L. A.; Cochran, T. H.

    1974-01-01

    Experiments were conducted in which the burning of cylindrical materials in a flowing oxidant stream was studied. Plexiglas, Nylon, and Teflon fuel specimens were oriented such that the flames spread along the surface in a direction opposed to flowing gas. Correlations of flame spread rate were obtained that were power law relations in terms of pressure, oxygen concentration, and gas velocity.

  15. Contralateral limb deficit after ACL-reconstruction: an analysis of early and late phase of rate of force development.

    Science.gov (United States)

    Mirkov, Dragan M; Knezevic, Olivera M; Maffiuletti, Nicola A; Kadija, Marko; Nedeljkovic, Aleksandar; Jaric, Slobodan

    2017-03-01

    The aim of this study was to assess the effect of a unilateral anterior cruciate ligament reconstruction (ACLR) on maximum voluntary contraction (MVC) and explosive strength of both the involved limb and the uninvolved limb. Nineteen male athletes completed a standard isometric testing protocol 4 months post-ACLR, while 16 healthy participants served as a control group (CG). The explosive strength of the knee extensors and flexors was assessed as RFD obtained from the slope of the force-time curves over various time intervals. Both muscle groups of the involved limb had significantly lower MVC compared to the uninvolved. The involved limb also had significantly lower RFD in the late phase of contraction (140-250 ms) for both knee extensors and flexors (P < 0.05). There was no difference in MVC between the uninvolved limb and the CG. However, RFD of the uninvolved limb was lower compared to CG for both knee extensors (0-180 ms; P < 0.01) and flexors (0-150 ms; P < 0.05). ACLR leads to lower MVC and explosive strength of the involved limb. As a consequence of potential crossover (presumably neural-mediated) effects, explosive strength deficits could be bilateral, particularly in the early phase of the contraction (<100 ms).

  16. Rate of decline of forced vital capacity predicts future arterial hypertension: the Coronary Artery Risk Development in Young Adults Study.

    Science.gov (United States)

    Jacobs, David R; Yatsuya, Hiroshi; Hearst, Mary O; Thyagarajan, Bharat; Kalhan, Ravi; Rosenberg, Sharon; Smith, Lewis J; Barr, R Graham; Duprez, Daniel A

    2012-02-01

    Lung function studies in middle-aged subjects predict cardiovascular disease mortality. We studied whether greater loss of forced vital capacity (FVC) early in life predicted incident hypertension. The sample was 3205 black and white men and women in the Coronary Artery Risk Development in Young Adults Study examined between 1985 and 1986 (Coronary Artery Risk Development in Young Adults year 0, ages 18-30 years) and 2005-2006 and who were not hypertensive by year 10. FVC was assessed at years 0, 2, 5, 10, and 20. Proportional hazard ratios and linear regression models predicted incident hypertension at years 15 or 20 (n=508) from the change in FVC (FVC at year 10 - peak FVC, where peak FVC was estimated as the maximum across years 0, 2, 5, and 10). Covariates included demographics, center, systolic blood pressure, FVC maximum, smoking, physical activity, asthma, and body mass index. Unadjusted cumulative incident hypertension was 25% in the lowest FVC loss quartile (Q1; median loss: 370 mL) compared with 12% cumulative incident hypertension in those who achieved peak FVC at year 10 (Q4). Minimally adjusted hazard ratio for Q1 versus Q4 was 2.21 (95% CI: 1.73-2.83), and this association remained significant in the fully adjusted model (1.37; 95% CI: 1.05-1.80). Decline in FVC from average age at peak (29.4 years) to 35 years old predicted incident hypertension between average ages 35 and 45 years. The findings may represent a common pathway that may link low normal FVC to cardiovascular disease morbidity and mortality.

  17. Large scale atmospheric forcing and topographic modification of precipitation rates over High Asia – a neural network based approach

    Directory of Open Access Journals (Sweden)

    L. Gerlitz

    2014-10-01

    Full Text Available The heterogeneity of precipitation rates in high mountain regions is not sufficiently captured by state of the art climate reanalysis products due to their limited spatial resolution. Thus there exists a large gap between the available data sets and the demands of climate impact studies. The presented approach aims to generate spatially high resolution precipitation fields for a target area in Central Asia, covering the Tibetan Plateau, the adjacent mountain ranges and lowlands. Based on the assumption, that observed local scale precipitation amounts are triggered by varying large scale atmospheric situations and modified by local scale topographic characteristics, the statistical downscaling approach estimates local scale precipitation rates as a function of large scale atmospheric conditions, derived from the ERA-Interim reanalysis, and high resolution terrain parameters. Since the relationships of the predictor variables with local scale observations are rather unknown and highly non-linear, an Artificial Neural Network (ANN was utilized for the development of adequate transfer functions. Different ANN-architectures were evaluated with regard to their predictive performance. The final downscaling model was used for the cellwise estimation of monthly precipitation sums, the number of rainy days and the maximum daily precipitation amount with a spatial resolution of 1 km2. The model was found to sufficiently capture the temporal and spatial variations of precipitation rates in the highly structured target area and allows a detailed analysis of the precipitation distribution. A concluding sensitivity analysis of the ANN model reveals the effect of the atmospheric and topographic predictor variables on the precipitation estimations in the climatically diverse subregions.

  18. Evidence of circadian rhythm, oxygen regulation capacity, metabolic repeatability and positive correlations between forced and spontaneous maximal metabolic rates in lake sturgeon Acipenser fulvescens.

    Directory of Open Access Journals (Sweden)

    Jon C Svendsen

    Full Text Available Animal metabolic rate is variable and may be affected by endogenous and exogenous factors, but such relationships remain poorly understood in many primitive fishes, including members of the family Acipenseridae (sturgeons. Using juvenile lake sturgeon (Acipenser fulvescens, the objective of this study was to test four hypotheses: 1 A. fulvescens exhibits a circadian rhythm influencing metabolic rate and behaviour; 2 A. fulvescens has the capacity to regulate metabolic rate when exposed to environmental hypoxia; 3 measurements of forced maximum metabolic rate (MMR(F are repeatable in individual fish; and 4 MMR(F correlates positively with spontaneous maximum metabolic rate (MMR(S. Metabolic rates were measured using intermittent flow respirometry, and a standard chase protocol was employed to elicit MMR(F. Trials lasting 24 h were used to measure standard metabolic rate (SMR and MMR(S. Repeatability and correlations between MMR(F and MMR(S were analyzed using residual body mass corrected values. Results revealed that A. fulvescens exhibit a circadian rhythm in metabolic rate, with metabolism peaking at dawn. SMR was unaffected by hypoxia (30% air saturation (O(2sat, demonstrating oxygen regulation. In contrast, MMR(F was affected by hypoxia and decreased across the range from 100% O(2sat to 70% O(2sat. MMR(F was repeatable in individual fish, and MMR(F correlated positively with MMR(S, but the relationships between MMR(F and MMR(S were only revealed in fish exposed to hypoxia or 24 h constant light (i.e. environmental stressor. Our study provides evidence that the physiology of A. fulvescens is influenced by a circadian rhythm and suggests that A. fulvescens is an oxygen regulator, like most teleost fish. Finally, metabolic repeatability and positive correlations between MMR(F and MMR(S support the conjecture that MMR(F represents a measure of organism performance that could be a target of natural selection.

  19. Effect of contraction mode of slow-speed resistance training on the maximum rate of force development in the human quadriceps

    DEFF Research Database (Denmark)

    Blazevich, Anthony J; Horne, Sara; Cannavan, Dale

    2008-01-01

    knee extension training was performed 3 x week(-1) for 10 weeks. Maximal isometric strength (+11.2%) and RFD (measured from 0-30/50/100/200 ms, respectively; +10.5%-20.5%) increased after 10 weeks (P training mode. Peak EMG amplitude and rate of EMG rise......This study examined the effects of slow-speed resistance training involving concentric (CON, n = 10) versus eccentric (ECC, n = 11) single-joint muscle contractions on contractile rate of force development (RFD) and neuromuscular activity (EMG), and its maintenance through detraining. Isokinetic...... were not significantly altered with training or detraining. Subjects with below-median normalized RFD (RFD/MVC) at 0 weeks significantly increased RFD after 5- and 10-weeks training, which was associated with increased neuromuscular activity. Subjects who maintained their higher RFD after detraining...

  20. Resource supply overrides temperature as a controlling factor of marine phytoplankton growth.

    Science.gov (United States)

    Marañón, Emilio; Cermeño, Pedro; Huete-Ortega, María; López-Sandoval, Daffne C; Mouriño-Carballido, Beatriz; Rodríguez-Ramos, Tamara

    2014-01-01

    The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated.

  1. Resource supply overrides temperature as a controlling factor of marine phytoplankton growth.

    Directory of Open Access Journals (Sweden)

    Emilio Marañón

    Full Text Available The universal temperature dependence of metabolic rates has been used to predict how ocean biology will respond to ocean warming. Determining the temperature sensitivity of phytoplankton metabolism and growth is of special importance because this group of organisms is responsible for nearly half of global primary production, sustains most marine food webs, and contributes to regulate the exchange of CO2 between the ocean and the atmosphere. Phytoplankton growth rates increase with temperature under optimal growth conditions in the laboratory, but it is unclear whether the same degree of temperature dependence exists in nature, where resources are often limiting. Here we use concurrent measurements of phytoplankton biomass and carbon fixation rates in polar, temperate and tropical regions to determine the role of temperature and resource supply in controlling the large-scale variability of in situ metabolic rates. We identify a biogeographic pattern in phytoplankton metabolic rates, which increase from the oligotrophic subtropical gyres to temperate regions and then coastal waters. Variability in phytoplankton growth is driven by changes in resource supply and appears to be independent of seawater temperature. The lack of temperature sensitivity of realized phytoplankton growth is consistent with the limited applicability of Arrhenius enzymatic kinetics when substrate concentrations are low. Our results suggest that, due to widespread resource limitation in the ocean, the direct effect of sea surface warming upon phytoplankton growth and productivity may be smaller than anticipated.

  2. Fairness overrides reputation: the importance of fairness considerations in altruistic cooperation.

    Science.gov (United States)

    Güney, Sule; Newell, Ben R

    2013-01-01

    Behavioral findings in several strategic games indicate that people punish others if they think they are being treated unequally, even at the cost of minimizing their own material payoff. We investigated the primary driving force behind such non-self-regarding behavior, so-called, altruistic cooperation. In all of our studies, a mini ultimatum game was played either one-shot (in Experiment 1a and 1b) or repeatedly (Experiment 2), and rejections of inequitable distribution were taken as a measure of altruistic cooperation. In Experiment 1a, we replicated previous findings indicating that the key mechanism contributing to the emergence of altruistic cooperation is fairness considerations. In Experiment 1b, we delved into the relative importance of two aspects of fairness considerations (i.e., outcome fairness and intentions) and showed that both aspects were effective in determining the level of altruistic cooperation, with the contribution of intentions being more important. In Experiment 2, we investigated the effect of the opportunity for reputation building and future interaction on altruistic cooperation. We found that these factors became influential only when fairness considerations were weakened, particularly, as a result of the removal of the possible intentions behind an offer.

  3. Maternal Western Diet Overrides Genetic Resistance to Obesity: : Role of TRH-DE

    OpenAIRE

    Frihauf, Jennifer Becker

    2014-01-01

    The dramatic rise in obesity rates in the United States over the last 30 years is likely a result of a combination of genetic and environmental factors. Genetic background can predispose an individual to obesity, while an environment rich in energy dense foods can promote overconsumption. Working in conjunction, genes and environment alter the regulatory systems responsible for maintaining energy balance. It has become increasingly clear that environmental factors can affect energy homeostasi...

  4. Self-rated health and its relationship to health/ life problems and coping strategies in members of the professional Slovenian armed forces.

    Science.gov (United States)

    Selić, Polona; Petek, Davorina; Serec, Masa; Makovec, Maja Rus

    2012-12-01

    The aim of this study was to test the association between self-rated health status (i.e. psychological and interpersonal welfare, physical health, coping mechanisms) and absence from work due to illness in the Slovenian armed forces. 390 military personnel were included in the study. Two groups of soldiers, healthy (G1-H) and sick/less healthy (G2-S), were created according to the median value of their annual sick leave. A third group consisted of soldiers on a mission (G3-M). A background questionnaire (demographic data, lifestyle habits, a list of life problems and a list of health problems in the last three years), a Self-Rated Health Scale and the Folkman-Lazarus Ways of Coping Questionnaire were administered. Self-rated physical health was best in group G1-H and worst in G2-S, with differences between the groups being statistically significant. No gender differences were found either between the groups or in the whole sample. The most common coping strategies amongst all the soldiers were found to be problem solving, positive re-evaluation of the situation and self-control. The groups differed only in their use of the distancing strategy. The self-rated health of all the participants was found to be in strong negative correlation with the escape/avoidance coping strategy. In group G2-S, more soldiers assessed their health as poor; the differences between the groups were statistically significant. Strong positive correlations between self-rated health and satisfaction with interpersonal relationships were found. Self-rated health was found to be significantly associated with the quality of interpersonal relationships and the socio-economic and psycho-physical conditions of the soldiers.

  5. A mechanistic-stochastic formulation of bed load particle motions: From individual particle forces to the Fokker-Planck equation under low transport rates

    Science.gov (United States)

    Fan, Niannian; Zhong, Deyu; Wu, Baosheng; Foufoula-Georgiou, Efi; Guala, Michele

    2014-03-01

    Bed load transport is a highly complex process. The probability density function (PDF) of particle velocities results from the local particle momentum variability in response to fluid drag and interactions with the bed. Starting from the forces exerted on a single particle under low transport rates (i.e., rolling and sliding regimes), we derive here the nonlinear stochastic Langevin equation (LE) to describe the dynamics of a single particle, accounting for both the deterministic and the stochastic components of such forces. Then, the Fokker-Planck equation (FPE), which describes the evolution of the PDF of the ensemble particle velocities, is derived from the LE. We show that the theoretical PDFs of both streamwise and cross-stream velocities obtained by solving the FPE under equilibrium conditions have exponential form (PDFs of both positive and negative velocities decay exponentially), consistent with the experimental data by Roseberry et al. Moreover, we theoretically show how the exponential-like PDF of an ensemble of particle velocities results from the forces exerted on a single particle. We also show that the simulated particle motions using the proposed Langevin model exhibit an emergent nonlinear relationship between hop distances and travel times (power law with exponent 5/3), in agreement with the experimental data, providing a statistical description of the particles' random motion in the context of a stochastic transport process. Finally, our study emphasizes that the motion of individual particles, described by the LE, and the behavior of the ensemble, described by the FPE, are connected within a statistical mechanics framework.

  6. Direct Radiative Effect and Heating Rate of black carbon aerosol: high time resolution measurements and source-identified forcing effects

    Science.gov (United States)

    Ferrero, Luca; Mocnik, Grisa; Cogliati, Sergio; Comi, Alberto; Degni, Francesca; Di Mauro, Biagio; Colombo, Roberto; Bolzacchini, Ezio

    2016-04-01

    Black carbon (BC) absorbs sunlight in the atmosphere heating it. However, up to now, heating rate (HR) calculations from the divergence of the net radiative flux with altitude or from the modelling activity are too sparse. This work fills the aforementioned gap presenting a new methodology based on a full set of physical equations to experimentally determine both the radiative power density absorbed into a ground-based atmospheric layer (ADRE), and the consequent HR induced by the absorptive component of aerosol. In urban context, it is essentially related to the BC. The methodology is also applicable to natural components (i.e. dust) and is obtained solving the first derivative of the main radiative transfer equations. The ADRE and the consequent HR can be determined coupling spectral aerosol absorption measurements with the spectrally resolved measurements of the direct, diffuse downward radiation and the surface reflected radiance components. Moreover, the spectral absorption of BC aerosol allows its source apportionment (traffic and biomass burning (BB)) allowing the same apportionment on HR. This work reports one year of high-time resolution measurements (5 min) of sunlight absorption and HR induced by BC aerosol over Milan. A unique sampling site was set up from March 2015 with: 1) Aethalometer (AE-31, Magee Scientific, 7-λ), 2) the Multiplexer-Radiometer-Irradiometer which detects downward and reflected radiance (350-1000 nm in 3648 spectral bands) coupled with a rotating shadow-band to measure spectrally-resolved global and diffuse radiation (thus direct), 3) a meteorological station (LSI-Lastem) equipped with 3 pyranometers (global, diffuse and refrected radiation; 300-3000 nm), a thermohygrometer, a barometer, an anemometer, 4) condensation and optical particle counters (TSI 3775 and Grimm 1.107), 5) low volume sampler (FAI Hydra dual sampler, PM2.5 and PM10) for sample collection and chemistry determination. Results concerning the radiative power

  7. Reduced effectiveness of escitalopram in the forced swimming test is associated with increased serotonin clearance rate in food-restricted rats.

    Science.gov (United States)

    France, Charles P; Li, Jun-Xu; Owens, William A; Koek, Wouter; Toney, Glenn M; Daws, Lynette C

    2009-07-01

    Efficacy of antidepressant drugs is often limited. One of the limiting factors may be diet. This study shows that the effect of escitalopram in the forced swimming test is diminished in rats by food restriction that decreased body weight by 8%. The primary target for escitalopram is the serotonin (5-HT) transporter. Using high-speed chronoamperometry to measure 5-HT clearance in vivo in rats fed the same food-restricted diet, the rate of 5-HT clearance from extracellular fluid in brain was dramatically increased. Increased 5-HT transporter function under conditions of dietary restriction might contribute to the decreased effect of escitalopram. These results suggest that diet plays an integral role in determining efficacy of antidepressant drugs, and might well generalize to other psychoactive drugs that impinge upon the 5-HT transporter.

  8. Overriding follicle selection in controlled ovarian stimulation protocols: Quality vs quantity

    Directory of Open Access Journals (Sweden)

    Zelinski-Wooten Mary B

    2004-06-01

    Full Text Available Abstract Selection of the species-specific number of follicles that will develop and ovulate during the ovarian cycle can be overridden by increasing the levels of pituitary gonadotropin hormones, FSH and LH. During controlled ovarian stimulation (COS in nonhuman primates for assisted reproductive technology (ART protocols, the method of choice (but not the only method has been the administration of exogenous gonadotropins, either of nonprimate or primate origin. Due to species-specificity of the primate LH (but not FSH receptor, COS with nonprimate (e.g., PMSG hormones can be attributed to their FSH activity. Elevated levels of FSH alone will produce large antral follicles containing oocytes capable of fertilization in vitro (IVF. However, there is evidence that LH, probably in lesser amounts, increases the rate of follicular development, reduces heterogeneity of the antral follicle pool, and improves the viability and rate of pre-implantation development of IVF-produced embryos. Since an endogenous LH surge typically does not occur during COS cycles (especially when a GnRH antagonist is added, a large dose of an LH-like hormone (i.e., hCG may be given to reinitiate meiosis and produce fertilizable oocytes. Alternate approaches using exogenous LH (or FSH, or GnRH agonist to induce an endogenous LH surge, have received lesser attention. Current protocols will routinely yield dozens of large follicles with fertilizable eggs. However, limitations include non/poor-responding animals, heterogeneity of follicles (and presumably oocytes and subsequent short luteal phases (limiting embryo transfer in COS cycles. However, the most serious limitation to further improvements and expanded use of COS protocols for ART is the lack of availability of nonhuman primate gonadotropins. Human, and even more so, nonprimate gonadotropins are antigenic in monkeys, which limits the number of COS cycles to as few as 1 (PMSG or 3 (recombinant hCG protocols in macaques

  9. Revealing Hidden Deformation Sources in New Zealand: a Novel Inversion of GPS Data for Non-Prescriptive Physics-Based Surface Forces and High-Precision Strain Rates

    Science.gov (United States)

    Dimitrova, L. L.; Haines, A. J.; Wallace, L. M.; Williams, C. A.

    2013-12-01

    Monitoring strain accumulation in active deformation zones is vital for studying and preparing for earthquake hazards. New Zealand straddles the complicated boundary between the obliquely converging Australian and Pacific plates. The motion is accommodated largely along the Alpine Fault in the south, through the Marlborough fault system and onto the Hikurangi trench in the north. In addition, a significant component of the motion is distributed on smaller, poorly characterized faults. Dimitrova et al. (2012) showed that the vertical derivatives of horizontal stress (VDoHS) rates are a substantially higher resolution expression of subsurface sources of ongoing deformation than the GPS velocities or GPS derived strain rates. We expand this method to solve the horizontal force balance equations for the VDoHS in 2-D to obtain the highest possible resolution picture of the surface deformation pattern in New Zealand. We invert GPS data from campaign GPS observations spanning from 1995 to 2012 for the VDoHS that best fit the GPS velocities, without prescribing sources or zones of deformation, while fully accounting for the physics of the problem. Using the VDoHS rates we identify (1) areas of deformation due to well-known active faults, (2) areas of poorly characterized deformation, e.g. deformation along faults without slip rate information mapped from palaeo-seismicity, (3) areas of previously unknown deformation, potentially on hidden faults, and (4) areas undergoing post-seismic deformation. The VDoHS are integrated to produce the highest resolution to-date maps of strain rates. We identify an area of extensional areal strain between the Alpine fault and the Main Divide of the central Southern Alps indicating possible gravitational collapse of the Southern Alps. Relationships between the VDoHS and strain rates allow us to calculate the variation in fault slip rate and locking depth for the identified faults, and we show selected results for the Alpine Fault and the

  10. Differences in Patient Screening Mammography Rates Associated With Internist Gender and Level of Training and Change Following the 2009 U.S. Preventive Services Task Force Guidelines.

    Science.gov (United States)

    Brooks, Dawn J

    2016-06-01

    Significant discordance arose between screening mammography clinical practice guidelines published by different national health care organizations following the release of the U.S. Preventive Services Task Force (USPSTF) guidelines in 2009. This allowed for greater interprovider variation in clinical practice while remaining within standard of care. The objective of this study was to determine how differences in patient screening mammography rates between internal medicine physician subgroups defined by gender and level of training changed, if at all, following the release of the new guidelines. The study was an observational study including all internists and internal medicine residents at a single academic medical center, Dartmouth-Hitchcock Medical Center. Screening mammography rates were determined for patients of subgroups of internists defined by gender and level of training (attending vs resident physician) for the 2 years before and after the release of the updated screening guidelines. Patients having female attending internists as their primary care provider were more likely to undergo screening mammography than those having male attending or resident internists of either gender both before and after the release of the new guidelines, with the difference in patient screening mammography rates between physician subgroups increasing following their release (rates before and after, respectively, by subgroup: female attending = 67%, 64%; male attending = 56%, 50%; female resident = 58%, 41%; male resident = 55%, 41%; PInternist gender and level of training are associated with differences in patient screening mammography rates at one academic medical center, with these differences increasing following the 2009 USPSTF guidelines. These findings suggest that the correlation between provider gender/level of training and a woman's likelihood of undergoing a screening mammogram strengthened as discordance arose between clinical guidelines published by different

  11. Effects of combined and classic training on different isometric rate of force development parameters of leg extensors in female volleyball players: Discriminative analysis approach

    Directory of Open Access Journals (Sweden)

    Rajić Branislav

    2013-01-01

    Full Text Available Background: The aim of this study is to verify the effects of the combined and classic training of different isometric rates of force development (RFD parameters of legs. Materials and Methods: Three groups of female athletes was tested: Experimental group (N = 12, classically trained group (N = 11, and control group (N = 20 of athletes. The isometric "standing leg extension" and "Rise on Toes" tests were conducted to evaluate the maximal force, time necessary time to reach it and the RFD analyzed at 100 ms, 180 ms, 250 ms from the onset, and 50-100% of its maximal result. Results: The maximal RFD of legs and calves are dominant explosive parameters. Special training enhanced the RFD of calves of GROUP SPEC at 100 ms (P = 0.05, at 180 ms (P = 0.039, at 250 ms (P = 0.039, at 50% of the F max (P = 0.031 and the F max (P = 0.05. Domination of GROUP SPEC toward GROUP CLASS and GROUP CONTROL is in case of legs at 100 ms (P = 0.04; at 180 ms (P = 0.04; at 250 ms (P = 0.00; at 50% of the F max (P = 0.01 and at the F max (P = 0.00; in case of calves at 100 ms (P = 0.07; 180 ms (P = 0.001; at 250 ms (P = 0.00; at 50% of the F max (P = 0.00 and at F max (P = 0.000. Conclusion: Dominant explosive factors are maximal RFD of leg extensors and calves, and legs at 250ms. Specific training enhanced explosiveness of calves of GROUP SPEC general and partial domination of GROUP SPEC by 87% over GROUP CLASS , and 35% over GROUP CONTROL .

  12. In vitro release testing of matrices based on starch-methyl methacrylate copolymers: effect of tablet crushing force, dissolution medium pH and stirring rate.

    Science.gov (United States)

    Ferrero, C; Jiménez-Castellanos, M R

    2014-01-30

    Direct-compressed matrix tablets were obtained from a variety of potato starch-methyl methacrylate copolymers(1) as sustained-release agents, using anhydrous theophylline as a model drug. The aim of this work was to investigate the influence of the copolymer type, the tablet crushing force and dissolution variables such as the pH of the dissolution medium and the agitation intensity on the in vitro drug release behaviour of such matrices. Commercial sustained-release theophylline products (Theo-Dur(®) 100mg, Theolair(®) 175 mg) were used as standards. Test formulations were compacted into tablets at three different crushing force ranges (70-80, 90-100 and 110-120 N) to examine the effect of this factor on the porous network and drug release kinetics. In vitro release experiments were conducted in a pH-changing medium (1.2-7.5) with basket rotation speeds in the range 25-100 r.p.m. to simulate the physiological conditions of the gastrointestinal tract. The release rate of theophylline was practically not affected by pH in the case of Theo-Dur(®) and HSMMA matrices. In contrast, Theolair(®) and CSMMA tablets demonstrated a biphasic drug release pattern, which appeared to be sensitive to the pH of the dissolution medium. An increase in the crushing force of the copolymer matrices was accompanied by a reduction of the matrix porosity, although the porous network depends markedly on the type of copolymer, having a strong influence on the drug release kinetics. Mathematical modelling of release data shows a Fickian diffusion or anomalous transport mechanism. Based on the similarity factor f2, FD-HSMMA, OD-CSMMA and FD-CSMMA at 90-100 N were selected for agitation studies. In general, all formulations showed an agitation speed-dependent release, with Theo-Dur(®) and FD-CSMMA matrices being the less susceptible to this factor. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. National Prostate Cancer Screening Rates After the 2012 US Preventive Services Task Force Recommendation Discouraging Prostate-Specific Antigen-Based Screening.

    Science.gov (United States)

    Drazer, Michael W; Huo, Dezheng; Eggener, Scott E

    2015-08-01

    In 2012, the US Preventive Services Task Force (USPSTF) discouraged prostate-specific antigen (PSA) -based prostate cancer screening. Previous USPSTF recommendations did not appreciably alter prostate cancer screening. Therefore, we designed a trend analysis to determine the population-based impact of the 2012 recommendation. The nationally representative National Health Interview Survey was used to estimate the proportion of men age 40 years and older who saw a physician and were screened for prostate cancer in 2013. An externally validated 9-year mortality index was used to analyze screening rates based on remaining life expectancy. Screening rates from 2005, 2010, and 2013 were compared using logistic regression. PSA-based screening did not significantly change from 2010 to 2013 among 40- to 49-year-old men (from 12.5% to 11.2%; P = .4). Screening rates significantly declined in men age 50 to 59 years (from 33.2% to 24.8%; P screened for prostate cancer despite a high risk (> 52%) of 9-year mortality, including approximately one third of men older than age 75 years. Approximately 1.4 million men age 65 years or older with a high risk (> 52%) of 9-year mortality were screened in 2013. Prostate cancer screening significantly declined among men older than age 50 years after the 2012 USPSTF guideline discouraging PSA-based screening. A significant proportion of men continue to be screened despite a high risk of 9-year mortality, including one third of men age 75 years and older. © 2015 by American Society of Clinical Oncology.

  14. Bile acids override steatosis in farnesoid X receptor deficient mice in a model of non-alcoholic steatohepatitis

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Weibin; Liu, Xijun; Peng, Xiaomin [Gene Research Center, Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Xue, Ruyi [Department of Gastroenterology and Hepatology, Zhongshan Hospital, Shanghai Institute of Liver Disease, Fudan University, Shanghai 200032 (China); Ji, Lingling [Gene Research Center, Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Shen, Xizhong [Department of Gastroenterology and Hepatology, Zhongshan Hospital, Shanghai Institute of Liver Disease, Fudan University, Shanghai 200032 (China); Chen, She, E-mail: shechen@fudan.edu.cn [Gene Research Center, Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Gu, Jianxin [Gene Research Center, Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Zhang, Si, E-mail: zhangsi@fudan.edu.cn [Gene Research Center, Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China)

    2014-05-23

    Highlights: • FXR deficiency enhanced MCD diet-induced hepatic fibrosis. • FXR deficiency attenuated MCD diet-induced hepatic steatosis. • FXR deficiency repressed genes involved in fatty acid uptake and triglyceride accumulation. - Abstract: Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, and the pathogenesis is still not well known. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily and plays an essential role in maintaining bile acid and lipid homeostasis. In this study, we study the role of FXR in the pathogenesis of NFALD. We found that FXR deficient (FXR{sup −/−}) mice fed methionine- and choline-deficient (MCD) diet had higher serum ALT and AST activities and lower hepatic triglyceride levels than wild-type (WT) mice fed MCD diet. Expression of genes involved in inflammation (VCAM-1) and fibrosis (α-SMA) was increased in FXR{sup −/−} mice fed MCD diet (FXR{sup −/−}/MCD) compared to WT mice fed MCD diet (WT/MCD). Although MCD diet significantly induced hepatic fibrosis in terms of liver histology, FXR{sup −/−}/MCD mice showed less degree of hepatic steatosis than WT/MCD mice. Moreover, FXR deficiency synergistically potentiated the elevation effects of MCD diet on serum and hepatic bile acids levels. The super-physiological concentrations of hepatic bile acids in FXR{sup −/−}/MCD mice inhibited the expression of genes involved in fatty acid uptake and triglyceride accumulation, which may be an explanation for less steatosis in FXR{sup −/−}/MCD mice in contrast to WT/MCD mice. These results suggest that hepatic bile acids accumulation could override simple steatosis in hepatic injury during the progression of NAFLD and further emphasize the role of FXR in maintaining hepatic bile acid homeostasis in liver disorders and in hepatic protection.

  15. The Overriding Interest

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Twenty years ago,far-sighted leaders of China and the Association of Southeast Asian Nations(ASEAN)launched a dialogue that deep-ened mutual understanding and trust,and helped forge close cooperation between the two sides.Since then,China and ASEAN have bolstered part-nerships in

  16. Forcing Mechanisms for the Variations of Near-surface Temperature Lapse Rates along the Himalayas, Tibetan Plateau (HTP) and Their Surroundings

    Science.gov (United States)

    Kattel, D. B.; Yao, T.; Ullah, K.; Islam, G. M. T.

    2016-12-01

    This study investigates the monthly characteristics of near-surface temperature lapse rates (TLRs) (i.e., governed by surface energy balance) based on the 176 stations 30-year (1980 to 2010) dataset covering a wide range of topography, climatic regime and relief (4801 m) in the HTP and its surroundings. Empirical analysis based on techniques in thermodynamics and hydrostatic system were used to obtain the results. Steepest TLRs in summer is due to strong dry convection and shallowest in winter is due to inversion effect is the general pattern of TLR that reported in previous studies in other mountainous region. Result of this study reports a contrast variation of TLRs from general patterns, and suggest distinct forcing mechanisms in an annual cycle. Shallower lapse rate occurs in summer throughout the regions is due to strong heat exchange process within the boundary layer, corresponding to the warm and moist atmospheric conditions. There is a systematic differences of TLRs in winter between the northern and southern slopes the Himalayas. Steeper TLRs in winter on the northern slopes is due to intense cooling at higher elevations, corresponding to the continental dry and cold air surges, and considerable snow-temperature feedback. The differences in elevation and topography, as well as the distinct variation of turbulent heating and cooling, explain the contrast TLRs (shallower) values in winter on the southern slopes. Distinct diurnal variations of TLRs and its magnitudes between alpine, dry, humid and coastal regions is due to the variations of adiabatic mixing during the daytime in the boundary layer i.e., associated with the variations in net radiations, elevation, surface roughness and sea surface temperature. The findings of this study is useful to determine the temperature range for accurately modelling in various field such as hydrology, glaciology, ecology, forestry, agriculture, as well as inevitable for climate downscaling in complex mountainous terrain.

  17. Rate-dependent force, intracellular calcium, and action potential voltage alternans are modulated by sarcomere length and heart failure induced-remodeling of thin filament regulation in human heart failure: A myocyte modeling study.

    Science.gov (United States)

    Zile, Melanie A; Trayanova, Natalia A

    2016-01-01

    Microvolt T-wave alternans (MTWA) testing identifies heart failure patients at risk for lethal ventricular arrhythmias at near-resting heart rates (voltage alternans (APV-ALT), the cellular driver of MTWA. Our goal was to uncover the mechanisms linking APV-ALT and FORCE-ALT in failing human myocytes and to investigate how the link between those alternans was affected by pacing rate and by physiological conditions such as sarcomere length and heart failure induced-remodeling of mechanical parameters. To achieve this, a mechanically-based, strongly coupled human electromechanical myocyte model was constructed. Reducing the sarcoplasmic reticulum calcium uptake current (Iup) to 27% was incorporated to simulate abnormal calcium handling in human heart failure. Mechanical remodeling was incorporated to simulate altered thin filament activation and crossbridge (XB) cycling rates. A dynamical pacing protocol was used to investigate the development of intracellular calcium concentration ([Ca]i), voltage, and active force alternans at different pacing rates. FORCE-ALT only occurred in simulations incorporating reduced Iup, demonstrating that alternans in the intracellular calcium concentration (CA-ALT) induced FORCE-ALT. The magnitude of FORCE-ALT was found to be largest at clinically relevant pacing rates (<110 bpm), where APV-ALT was smallest. We found that the magnitudes of FORCE-ALT, CA-ALT and APV-ALT were altered by heart failure induced-remodeling of mechanical parameters and sarcomere length due to the presence of myofilament feedback. These findings provide important insight into the relationship between heart-failure-induced electrical and mechanical alternans and how they are altered by physiological conditions at near-resting heart rates.

  18. Sustainable energy for all. Technical report of task force 2 in support of doubling the global rate of energy efficiency improvement and doubling the share of renewable energy in the global energy mix by 2030

    Energy Technology Data Exchange (ETDEWEB)

    Nakicenovic, Nebojsa [International Institute for Applied Systems Analysis and Vienna University of Technology (Austria); Kammen, Daniel [Univ. of California, Berkeley, CA (United States); Jewell, Jessica [International Institute for Applied Systems Analysis (Austria)

    2012-04-15

    The UN Secretary General established the Sustainable Energy for All initiative in order to guide and support efforts to achieve universal access to modern energy, rapidly increase energy efficiency, and expand the use of renewable energies. Task forces were formed involving prominent energy leaders and experts from business, government, academia and civil society worldwide. The goal of the Task Forces is to inform the implementation of the initiative by identifying challenges and opportunities for achieving its objectives. This report contains the findings of Task Force Two which is dedicated energy efficiency and renewable energy objectives. The report shows that doubling the rate of energy efficiency improvements and doubling the share of energy from renewable sources by 2030 is challenging but feasible if sufficient actions are implemented. Strong and well-informed government policies as well as extensive private investment should focus on the high impact areas identified by the task force.

  19. Water-Based Concurrent Training Improves Peak Oxygen Uptake, Rate of Force Development, Jump Height, and Neuromuscular Economy in Young Women.

    Science.gov (United States)

    Pinto, Stephanie S; Alberton, Cristine L; Cadore, Eduardo L; Zaffari, Paula; Baroni, Bruno M; Lanferdini, Fábio J; Radaelli, Régis; Pantoja, Patrícia D; Peyré-Tartaruga, Leonardo A; Wolf Schoenell, Maira C; Vaz, Marco A; Kruel, Luiz F M

    2015-07-01

    The study investigated the effects of different intrasession exercise sequences on the cardiorespiratory and neuromuscular adaptations induced by water-based concurrent training in young subjects. Twenty-six healthy young women (25.1 ± 2.9 years) were placed into 2 water-based concurrent training groups: resistance before (RA, n = 13) or after (AR, n = 13) aerobic training. Subjects trained resistance and aerobic training during 12 weeks, 2 times per week performing both exercise types in the same training session. Peak oxygen uptake (V[Combining Dot Above]O2peak), rate of force development (RFD) obtained during an isometric peak torque knee extension protocol, jump height, and neuromuscular economy (normalized electromyography at 80% of pretraining knee extension isometric peak torque) in young women were determined. After training, there was a significant increase (p < 0.001) in both RA and AR in the V[Combining Dot Above]O2peak, with no differences between groups (7 vs. 5%). The maximal isometric knee extension RFD showed significant increases (p = 0.003) after training (RA: 19 vs. AR: 30%), and both groups presented similar gains. In addition, the countermovement jump height also increased (p = 0.034) after training (RA: 5% vs. AR: 6%), with no difference between groups. After training, there were significant improvements on vastus lateralis (p < 0.001) (RA: -13% vs. AR: -20%) and rectus femoris (p = 0.025) (RA: -17% vs. AR: -7%) neuromuscular economy, with no difference between groups. In conclusion, 12 weeks of water-based concurrent training improved the peak oxygen uptake, RFD, jump height, and neuromuscular economy in young women independent from the intrasession exercise sequence.

  20. Relationship between the estimated glomerular filtration rate and kidney shear wave speed values assessed by acoustic radiation force impulse elastography: a pilot study.

    Science.gov (United States)

    Bob, Flaviu; Bota, Simona; Sporea, Ioan; Sirli, Roxana; Popescu, Alina; Schiller, Adalbert

    2015-04-01

    The aim of the study was to establish the relationship between the estimated glomerular filtration rate (GFR) and kidney shear wave speed values assessed by acoustic radiation force impulse (ARFI) elastography. Our study included 104 patients with or without chronic kidney disease in which the kidney shear wave speed was evaluated by ARFI elastography and correlated with the estimated GFR. Five ARFI measurements were performed in the parenchyma of each kidney. A median value expressed as meters per second was calculated. Five valid ARFI elastographic measurements were obtained in the right kidney in all patients and in the left kidney in 97.1% of patients. The mean kidney shear wave speed values ± SD in the right and left kidneys were similar: 2.17 ± 0.81 versus 2.06 ± 0.75 m/s (P = .30). The mean kidney shear wave speed decreased with the decrease in the estimated GFR. Statistically significant differences were obtained only when kidney shear wave speed values obtained in patients with an estimated GFR of greater than 90 mL/min/1.73 m(2) were compared to values in patients with stage 4 (estimated GFR, 15-29 mL/min/1.73 m(2)) and stage 5 (estimated GFR, wave speed had 86.7% sensitivity, 48.3% specificity, a 22.1% positive predictive value, and a 95.6% negative predictive value (area under the receiver operating characteristic curve, 0.692; P = .008) for predicting the presence of an estimated GFR of less than 30 mL/min/1.73 m(2). Kidney shear wave speed values obtained by ARFI elastography decrease with the decrease in the estimated GFR. © 2015 by the American Institute of Ultrasound in Medicine.

  1. Visual Cues of Object Properties Differentially Affect Anticipatory Planning of Digit Forces and Placement.

    Science.gov (United States)

    Lee-Miller, Trevor; Marneweck, Michelle; Santello, Marco; Gordon, Andrew M

    2016-01-01

    Studies on anticipatory planning of object manipulation showed initial task failure (i.e., object roll) when visual object shape cues are incongruent with other visual cues, such as weight distribution/density (e.g., symmetrically shaped object with an asymmetrical density). This suggests that shape cues override density cues. However, these studies typically only measured forces, with digit placement constrained. Recent evidence suggests that when digit placement is unconstrained, subjects modulate digit forces and placement. Thus, unconstrained digit placement might be modulated on initial trials (since it is an explicit process), but not forces (since it is an implicit process). We tested whether shape and density cues would differentially influence anticipatory planning of digit placement and forces during initial trials of a two-digit object manipulation task. Furthermore, we tested whether shape cues would override density cues when cues are incongruent. Subjects grasped and lifted an object with the aim of preventing roll. In Experiment 1, the object was symmetrically shaped, but with asymmetrical density (incongruent cues). In Experiment 2, the object was asymmetrical in shape and density (congruent cues). In Experiment 3, the object was asymmetrically shaped, but with symmetrical density (incongruent cues). Results showed differential modulation of digit placement and forces (modulation of load force but not placement), but only when shape and density cues were congruent. When shape and density cues were incongruent, we found collinear digit placement and symmetrical force sharing. This suggests that congruent and incongruent shape and density cues differentially influence anticipatory planning of digit forces and placement. Furthermore, shape cues do not always override density cues. A continuum of visual cues, such as those alluding to shape and density, need to be integrated.

  2. Percentual de degradação das forças liberadas por ligaduras elásticas Force decay rate of orthodontic elastomeric ligatures

    Directory of Open Access Journals (Sweden)

    Emanoela Volles de Souza

    2008-04-01

    Full Text Available OBJETIVO: avaliar ligaduras elásticas da marca Morelli, dos tipos modular e bengala, nas cores cinza e cristal para determinação do percentual de degradação das forças geradas pelas mesmas. METODOLOGIA: as ligaduras elásticas foram estiradas em estiletes de aço inoxidável com diâmetro de 4mm, imersas em solução de saliva artificial a 37ºC, sendo a intensidade das forças liberadas medidas nos tempos de zero hora, 24 horas, 1 semana, 2 semanas, 3 semanas e 4 semanas, em máquina de ensaios de tração. RESULTADOS E CONCLUSÕES: as ligaduras do tipo bengala liberaram, em média e no período de 4 semanas, maior intensidade de força que as do tipo modular. O percentual de degradação das forças liberadas por todas as ligaduras aumentou de forma acentuada entre zero e 24 horas e de forma gradativa após este período, com exceção do 28º dia quando, provavelmente, houve perda das propriedades elásticas das ligaduras. Não foi observado um comportamento constante das ligaduras bengala e modular em relação às cores cinza e cristal.PURPOSE: to evaluate gray and clear module and cane-loaded elastomeric ligatures of the brand Morelli to determine the percentage of decay of the forces they deliver. METHODS: the elastomeric ligatures were stretched over 4mm diameter stainless steel dowels and placed in synthetic saliva bath at 37ºC. The intensity of the forces delivered were taken at start, after 24 hours, one week, two weeks, three weeks and four weeks at a tensile test machine. RESULTS AND CONCLUSIONS: the cane-loaded ligatures delivered, in a period of 4 weeks, in average, greater force intensity than the modules. The percentage of force decay of all ligatures increased rapidly between zero and 24 hours and gradually after that period, except for the 28th day, when probably there was a loss of elastic properties of the ligatures. The researchers did not note any constant behavior in the cane-loaded and module ligatures in relation

  3. Lack of proportionality. Seven specifications of public interest that override post-approval commercial interests on limited access to clinical data

    Directory of Open Access Journals (Sweden)

    Strech Daniel

    2012-07-01

    Full Text Available Abstract For the protection of commercial interests, licensing bodies such as the EMA and health technology assessment institutions such as NICE restrict full access to unpublished evidence. Their respective policies on data transparency, however, lack a systematic account of (1 what kinds of commercial interests remain relevant after market approval has been granted, (2 what the specific types of public interest are that may override these commercial interests post approval, and, most importantly, (3 what criteria guide the trade-off between public interest and legitimate measures for the protection of commercial interest. Comparing potential commercial interests with seven specifications of relevant public interest reveals the lack of proportionality inherent in the current practices of EMA and NICE.

  4. Nonlinear Dynamic Force Spectroscopy

    CERN Document Server

    Björnham, Oscar

    2016-01-01

    Dynamic force spectroscopy (DFS) is an experimental technique that is commonly used to assess information of the strength, energy landscape, and lifetime of noncovalent bio-molecular interactions. DFS traditionally requires an applied force that increases linearly with time so that the bio-complex under investigation is exposed to a constant loading rate. However, tethers or polymers can modulate the applied force in a nonlinear regime. For example, bacterial adhesion pili and polymers with worm-like chain properties are examples of structures that show nonlinear force responses. In these situations, the theory for traditional DFS cannot be readily applied. In this work we expand the theory for DFS to also include nonlinear external forces while still maintaining compatibility with the linear DFS theory. To validate the theory we modeled a bio-complex expressed on a stiff, an elastic and a worm-like chain polymer, using Monte Carlo methods, and assessed the corresponding rupture force spectra. It was found th...

  5. Labor Force

    Science.gov (United States)

    Occupational Outlook Quarterly, 2012

    2012-01-01

    The labor force is the number of people ages 16 or older who are either working or looking for work. It does not include active-duty military personnel or the institutionalized population, such as prison inmates. Determining the size of the labor force is a way of determining how big the economy can get. The size of the labor force depends on two…

  6. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate

    Directory of Open Access Journals (Sweden)

    William R. Reed

    2013-01-01

    Full Text Available High velocity low amplitude spinal manipulation (HVLA-SM is used frequently to treat musculoskeletal complaints. Little is known about the intervention’s biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20–30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

  7. Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate.

    Science.gov (United States)

    Reed, William R; Cao, Dong-Yuan; Long, Cynthia R; Kawchuk, Gregory N; Pickar, Joel G

    2013-01-01

    High velocity low amplitude spinal manipulation (HVLA-SM) is used frequently to treat musculoskeletal complaints. Little is known about the intervention's biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150 ms suggesting the presence of a threshold value. Thrust velocities greater than 20-30 mm/s and thrust rates greater than 300 N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

  8. Labor market work and home care's unpaid caregivers: a systematic review of labor force participation rates, predictors of labor market withdrawal, and hours of work.

    Science.gov (United States)

    Lilly, Meredith B; Laporte, Audrey; Coyte, Peter C

    2007-12-01

    As people continue to age and receive complex health care services at home, concern has arisen about the availability of family caregivers and their ability to combine employment with caregiving. This article evaluates the international research on unpaid caregivers and their labor market choices, highlighting three conclusions: first, caregivers in general are equally as likely to be in the labor force as noncaregivers; second, caregivers are more likely to work fewer hours in the labor market than noncaregivers, particularly if their caring commitments are heavy; and finally, only those heavily involved in caregiving are significantly more likely to withdraw from the labor market than noncaregivers. Policy recommendations are targeting greater access to formal care for "intensive" caregivers and developing workplace policies for employed caregivers.

  9. Dispersion Forces

    CERN Document Server

    Buhmann, Stefan Yoshi

    2012-01-01

    In this book, a modern unified theory of dispersion forces on atoms and bodies is presented which covers a broad range of advanced aspects and scenarios. Macroscopic quantum electrodynamics is shown to provide a powerful framework for dispersion forces which allows for discussing general properties like their non-additivity and the relation between microscopic and macroscopic interactions. It is demonstrated how the general results can be used to obtain dispersion forces on atoms in the presence of bodies of various shapes and materials. Starting with a brief recapitulation of volume I, this volume II deals especially with bodies of irregular shapes, universal scaling laws, dynamical forces on excited atoms, enhanced forces in cavity quantum electrodynamics, non-equilibrium forces in thermal environments and quantum friction. The book gives both the specialist and those new to the field a thorough overview over recent results in the field. It provides a toolbox for studying dispersion forces in various contex...

  10. Increased term life insurance based on ARCH force of interest rate%随机利息力ARCH模型下的递增定期寿险

    Institute of Scientific and Technical Information of China (English)

    李婷; 刘凌晨

    2015-01-01

    基于随机利息力A RC H模型 ,推导出递增 n年死亡保险保费公式、准备金计提公式 ,指出了随机利息力A RC H模型在保险精算业务中的应用性.%Based on random interest rate ARCH model ,the premium formula of increased n-year death insurance ,the reserve formula and the risk prediction formula are deduced .We give the applications of the random interest rate ARCH model in insurance practicability .

  11. Mixed Convection Blowoff Limits as a Function of Oxygen Concentration and Upward Forced Stretch Rate for Burning Pmma Rods of Various Sizes

    Science.gov (United States)

    Marcum, Jeremy W.; Ferkul, Paul V.; Olson, Sandra L.

    2017-01-01

    Normal gravity flame blowoff limits in an axisymmetric pmma rod geometry in upward axial stagnation flow are compared with microgravity Burning and Suppression of Solids II (BASS-II) results recently obtained aboard the International Space Station. This testing utilized the same BASS-II concurrent rod geometry, but with the addition of normal gravity buoyant flow. Cast polymethylmethacrylate (pmma) rods of diameters ranging from 0.635 cm to 3.81 cm were burned at oxygen concentrations ranging from 14 to 18 by volume. The forced flow velocity where blowoff occurred was determined for each rod size and oxygen concentration. These blowoff limits compare favorably with the BASS-II results when the buoyant stretch is included and the flow is corrected by considering the blockage factor of the fuel. From these results, the normal gravity blowoff boundary for this axisymmetric rod geometry is determined to be linear, with oxygen concentration directly proportional to flow speed. We describe a new normal gravity upward flame spread test method which extrapolates the linear blowoff boundary to the zero stretch limit to resolve microgravity flammability limits, something current methods cannot do. This new test method can improve spacecraft fire safety for future exploration missions by providing a tractable way to obtain good estimates of material flammability in low gravity.

  12. Effect of slow release-Fampridine on muscle strength, rate of force development, functional capacity and cognitive function in an enriched population of MS patients. A randomized, double blind, placebo controlled study

    DEFF Research Database (Denmark)

    Jensen, H B; Nielsen, J L; Ravnborg, M.

    2016-01-01

    contraction (MVC) and rate of force development (RFD) of the lower extremities and 2) to replicate previously published data on the effect of slow release-Fampridine (SR-Fampridine) on the functional capacity of the lower limbs, the upper limb and cognitive function, in persons with multiple sclerosis (pw....... Furthermore, a significant effect of SR-Fampridine on T25FW, SSST and 5-STS was demonstrated. CONCLUSION: Gold standard dynamometry assessment of muscle strength showed improved MVC and RFD in persons with MS treated with SR-Fampridine compared to placebo. Furthermore, previous findings on the effects of SR...

  13. Strong Force

    CERN Document Server

    Without the strong force, there could be no life. The carbon in living matter is synthesised in stars via the strong force. Lighter atomic nuclei become bound together in a process called nuclear fusion. A minor change in this interaction would make life impossible. As its name suggests, the strong force is the most powerful of the 4 forces, yet its sphere of influence is limited to within the atomic nucleus. Indeed it is the strong force that holds together the quarks inside the positively charged protons. Without this glue, the quarks would fly apart repulsed by electromagnetism. In fact, it is impossible to separate 2 quarks : so much energy is needed, that a second pair of quarks is produced. Text for the interactive: Can you pull apart the quarks inside a proton?

  14. Weak Force

    CERN Multimedia

    Without the weak force, the sun wouldn't shine. The weak force causes beta decay, a form of radioactivity that triggers nuclear fusion in the heart of the sun. The weak force is unlike other forces: it is characterised by disintegration. In beta decay, a down quark transforms into an up quark and an electron is emitted. Some materials are more radioactive than others because the delicate balance between the strong force and the weak force varies depending on the number of particles in the atomic nucleus. We live in the midst of a natural radioactive background that varies from region to region. For example, in Cornwall where there is a lot of granite, levels of background radiation are much higher than in the Geneva region. Text for the interactive: Move the Geiger counter to find out which samples are radioactive - you may be surprised. It is the weak force that is responsible for the Beta radioactivity here. The electrons emitted do not cross the plastic cover. Why do you think there is some detected radioa...

  15. Disulfiram, a drug widely used to control alcoholism, suppresses self-renewal of glioblastoma and overrides resistance to temozolomide

    Science.gov (United States)

    Triscott, Joanna; Lee, Cathy; Hu, Kaiji; Fotovati, Abbas; Berns, Rachel; Pambid, Mary; Luk, Margaret; Kast, Richard E.; Kong, Esther; Toyota, Eric; Yip, Stephen; Toyota, Brian; Dunn, Sandra E.

    2012-01-01

    Glioblastomas (GBM) are associated with high rates of relapse. These brain tumors are often resistant to chemotherapies like temozolomide (TMZ) and there are very few treatment options available to patients. We recently reported that polo-like kinase-1 (PLK1) is associated with the proliferative subtype of GBM; which has the worst prognosis. In this study, we addressed the potential of repurposing disulfiram (DSF), a drug widely used to control alcoholism for the past six decades. DSF has good safety profiles and penetrates the blood-brain barrier. Here we report that DSF inhibited the growth of TMZ resistant GBM cells, (IC90=100 nM), but did not affect normal human astrocytes. At similar DSF concentrations, self-renewal was blocked by ~100% using neurosphere growth assays. Likewise the drug completely inhibited the self-renewal of the BT74 and GBM4 primary cell lines. Additionally, DSF suppressed growth and self-renewal of primary cells from two GBM tumors. These cells were resistant to TMZ, had unmethylated MGMT, and expressed high levels of PLK1. Consistent with its role in suppressing GBM growth, DSF inhibited the expression of PLK1 in GBM cells. Likewise, PLK1 inhibition with siRNA, or small molecules (BI-2536 or BI-6727) blocked growth of TMZ resistant cells. Our studies suggest that DSF has the potential to be repurposed for treatment of refractory GBM. PMID:23047041

  16. Labour force participation and the feminising of the labour force

    OpenAIRE

    Brendan M. Walsh

    1992-01-01

    This paper studies the effects of changes in labour force particiapation rates on the size and structure of the Irish labour force over the period 1971-1991. The rise in participation rates among females aged 25-54 and the decline in participation among older and younger people of both sexes altered the structure of the labour force significantly. Time series of annual participation rates are used to explore the reasons for these changes. It is shown that participation rates among those aged ...

  17. Trabectedin Overrides Osteosarcoma Differentiative Block and Reprograms the Tumor Immune Environment Enabling Effective Combination with Immune Checkpoint Inhibitors.

    Science.gov (United States)

    Ratti, Chiara; Botti, Laura; Cancila, Valeria; Galvan, Silvia; Torselli, Ilaria; Garofalo, Cecilia; Manara, Maria Cristina; Bongiovanni, Lucia; Valenti, Cesare F; Burocchi, Alessia; Parenza, Mariella; Cappetti, Barbara; Sangaletti, Sabina; Tripodo, Claudio; Scotlandi, Katia; Colombo, Mario P; Chiodoni, Claudia

    2017-09-01

    Purpose: Osteosarcoma, the most common primary bone tumor, is characterized by an aggressive behavior with high tendency to develop lung metastases as well as by multiple genetic aberrations that have hindered the development of targeted therapies. New therapeutic approaches are urgently needed; however, novel combinations with immunotherapies and checkpoint inhibitors require suitable preclinical models with intact immune systems to be properly tested.Experimental Design: We have developed immunocompetent osteosarcoma models that grow orthotopically in the bone and spontaneously metastasize to the lungs, mimicking human osteosarcoma. These models have been used to test the efficacy of trabectedin, a chemotherapeutic drug utilized clinically for sarcomas and ovarian cancer.Results: Trabectedin, as monotherapy, significantly inhibited osteosarcoma primary tumor growth and lung metastases by both targeting neoplastic cells and reprogramming the tumor immune microenvironment. Specifically, trabectedin induced a striking differentiation of tumor cells by favoring the recruitment of Runx2, the master genetic regulator of osteoblastogenesis, on the promoter of genes involved in the physiologic process of terminal osteoblast differentiation. Differentiated neoplastic cells, as expected, showed reduced proliferation rate. Concomitantly, trabectedin enhanced the number of tumor-infiltrating T lymphocytes, with local CD8 T cells, however, likely post-activated or exhausted, as suggested by their high expression of the inhibitory checkpoint molecule PD-1. Accordingly, the combination with a PD-1-blocking antibody significantly increased trabectedin efficacy in controlling osteosarcoma progression.Conclusions: These results demonstrate the therapeutic efficacy of trabectedin in osteosarcoma treatment, unveiling its multiple activities and providing a solid rationale for its combination with immune checkpoint inhibitors. Clin Cancer Res; 23(17); 5149-61. ©2017 AACR. ©2017

  18. Control Strategies for Accurate Force Generation and Relaxation.

    Science.gov (United States)

    Ohtaka, Chiaki; Fujiwara, Motoko

    2016-10-01

    Characteristics and motor strategies for force generation and force relaxation were examined using graded tasks during isometric force control. Ten female college students (M age = 20.2 yr., SD = 1.1) were instructed to accurately control the force of isometric elbow flexion using their right arm to match a target force level as quickly as possible. They performed: (1) a generation task, wherein they increased their force from 0% maximum voluntary force to 20% maximum voluntary force (0%-20%), 40% maximum voluntary force (0%-40%), or 60% maximum voluntary force (0%-60%) and (2) and a relaxation task, in which they decreased their force from 60% maximum voluntary force to 40% maximum voluntary force (60%-40%), 20% maximum voluntary force (60%-20%), or to 0% maximum voluntary force (60%-0%). Produced force parameters of point of accuracy (force level, error), quickness (reaction time, adjustment time, rate of force development), and strategy (force wave, rate of force development) were analyzed. Errors of force relaxation were all greater, and reaction times shorter, than those of force generation. Adjustment time depended on the magnitude of force and peak rates of force development and force relaxation differed. Controlled relaxation of force is more difficult with low magnitude of force control.

  19. Forced Snaking

    Science.gov (United States)

    Ponedel, Benjamin; Knobloch, Edgar

    2016-11-01

    We study spatial localization in the real subcritical Ginzburg-Landau equation ut =m0 u +m1 cos2/π l x u +uxx +d | u | 2 u -| u | 4 u with spatially periodic forcing. When d > 0 and m1 = 0 this equation exhibits bistability between the trivial state u = 0 and a homogeneous nontrivial state u =u0 with stationary localized structures which accumulate at the Maxwell point m0 = - 3d2 / 16 . When spatial forcing is included its wavelength is imprinted on u0 creating conditions favorable to front pinning and hence spatial localization. We use numerical continuation to show that under appropriate conditions such forcing generates a sequence of localized states organized within a snakes-and-ladders structure centered on the Maxwell point, and refer to this phenomenon as forced snaking. We determine the stability properties of these states and show that longer lengthscale forcing leads to stationary trains consisting of a finite number of strongly localized, weakly interacting pulses exhibiting foliated snaking.

  20. Seismological structures of the subducted Philippine Sea plate and the overriding SW Japan arc, - Reinterpretation of the wide-angle reflection data in the Kii Peninsula, SW Japan -

    Science.gov (United States)

    Iwasaki, Takaya; Kurashimo, Eiji; Abe, Susumu; Yokota, Ken; Iidaka, Takashi; Katao, Hiroshi; Higashinaka, Motonori; Nakanishi, Ayako; Kaneda, Yoshiyuki

    2017-04-01

    Our recent reinterpretation for seismic refraction/wide-angle reflection data in eastern Kii Peninsula, SW Japan, provided new structural information on the uppermost part of the subducted Philippine Sea (PHS) plate and overriding the SW Japan arc, including the landward reflectivity variation in the vicinity of the plate boundary and the large scale structural change within the SW Japan arc. The Kii peninsula is located in the eastern part of the well-known subduction zone along the Nankai trough where offshore M8-class megathrust earthquakes repeatedly occur. The plate boundary beneath this Peninsula is in the stable or conditionally stable regime except for its southernmost tip, which corresponds to the northwestern end of the rupture area at the last event (1944 Tonankai earthquake (M7.9)). The surface geology of the overriding SW Japan arc is divided to two parts by the E-W trending Median Tectonic Line (MTL), the most prominent tectonic boundary in SW Japan. South of the MTL, Cretaceous-Jurassic accretionary complexes are exposed, whose northernmost unit consists of high P-T metamorphic rocks (the Sanbagawa metamorphic belt (SMB)). The region north of the MTL is occupied by older accretionary complexes, partly suffered from the Cretaceous magmatic intrusions. Our seismic data from five dynamite shots were acquired in 2006 along 80-km line almost perpendicular to the Nankai trough. The structure of the SW Japan arc was obtained both from intensive wide-angle reflection analysis and advanced reflection processing by seismic interferometry technique. The former analysis delineated clear structural change in the uppermost crust across the MTL. In the latter processing, we retrieved virtual shot records at 512 receiver points from free-surface backscattered waves by the deconvolution interferometry. The subsequent CRS (Common Reflection Surface)/MDRS (Multi-Dip Reflection Surfaces) methods provided an enhanced image within the island arc, including a northward

  1. Intermolecular forces.

    Science.gov (United States)

    Buckingham, A D

    1975-11-06

    The nature of molecular interactions is examined. Intermolecular forces are divided into long-range and short-range components; the former operate at distances where the effects of electron exchange are negligible and decrease as an inverse power of the separation. The long-range interactions may be subdividied into electrostatic, induction and dispersion contributions, where the electrostatic component is the interaction of the permanent charge distributions and the others originate in the fluctuations in the distributions. Typical magnitudes of the various contributions are given. The forces between macroscopic bodies are briefly considered, as are the effects of a medium. Some of the manifestations of molecular interactions are discussed.

  2. 住房自有率、人口流动与劳动力参与率--基于全国第六次人口普查数据的研究%The Rate of Homeownership, the Flow of Population and Labor Force Participation Rate---An Empirical Study based on Sixth National Census Data

    Institute of Scientific and Technical Information of China (English)

    刘斌

    2016-01-01

    In this paper, the sixth census data of China is used to establish a simultaneous equations model to study the influence of homeownership rate to population mobility and labor force participation rates. The empirical results show that high homeownership rate has a significant positive impact on labor force participation rate. The homeownership rate increases by 1%, and the labor force partici-pation rate increases about 0.13%. Meanwhile, high homeownership rate was significantly inhibited the mobility of the population. In addition, the research also finds that illiterate population, elderly population and unmarried, divorced widowed population proportion will reduce the labor force participation rate. The proportion of young people , unmarried people and secondary education will increase the mobility of the population. We put forward some policy suggestions, including eliminating the institutional barriers, blocking the floating population, developing rental housing business of the housing enterprises, further activing rental market, encouraging new employment population and floating population live in urban public rental housing.%文章以新型城镇化为背景,利用中国第六次人口普查分县数据建立联立方程模型,研究了中国住房自有率对人口流动性和劳动力参与率的影响。实证结果表明:高住房自有率对劳动力参与率具有显著的正向影响,住房自有率每提高1%,会引起劳动力参与率上升约0.13%;同时,高住房自有率对人口的流动性具有明显的抑制作用。此外,文章的研究还发现:文盲人口、老年人口和未婚、离婚丧偶人口比例越大,越有可能抑制劳动力参与率;而青年人口、未婚人口和中学学历等人口比重越大,人口流动性也会越大。在此基础上,文章还提出消除阻碍人口流动的制度性障碍;发展以住房租赁为主营业务的住房企业,进一步活跃租房市场;鼓励新

  3. Digit forces bias sensorimotor transformations underlying control of fingertip position.

    Science.gov (United States)

    Shibata, Daisuke; Kappers, Astrid M L; Santello, Marco

    2014-01-01

    Humans are able to modulate digit forces as a function of position despite changes in digit placement that might occur from trial to trial or when changing grip type for object manipulation. Although this phenomenon is likely to rely on sensing the position of the digits relative to each other and the object, the underlying mechanisms remain unclear. To address this question, we asked subjects (n = 30) to match perceived vertical distance between the center of pressure (CoP) of the thumb and index finger pads (dy ) of the right hand ("reference" hand) using the same hand ("test" hand). The digits of reference hand were passively placed collinearly (dy = 0 mm). Subjects were then asked to exert different combinations of normal and tangential digit forces (Fn and Ftan , respectively) using the reference hand and then match the memorized dy using the test hand. The reference hand exerted Ftan of thumb and index finger in either same or opposite direction. We hypothesized that, when the tangential forces of the digits are produced in opposite directions, matching error (1) would be biased toward the directions of the tangential forces; and (2) would be greater when the remembered relative contact points are matched with negligible digit force production. For the test hand, digit forces were either negligible (0.5-1 N, 0 ± 0.25 N; Experiment 1) or the same as those exerted by the reference hand (Experiment 2).Matching error was biased towards the direction of digit tangential forces: thumb CoP was placed higher than the index finger CoP when thumb and index finger Ftan were directed upward and downward, respectively, and vice versa (p < 0.001). However, matching error was not dependent on whether the reference and test hand exerted similar or different forces. We propose that the expected sensory consequence of motor commands for tangential forces in opposite directions overrides estimation of fingertip position through haptic sensory feedback.

  4. Digit forces bias sensorimotor transformations underlying control of fingertip position

    Directory of Open Access Journals (Sweden)

    Daisuke eShibata

    2014-08-01

    Full Text Available Humans are able to modulate digit forces as a function of position despite changes in digit placement that might occur from trial to trial or when changing grip type for object manipulation. Although this phenomenon is likely to rely on sensing the position of the digits relative to each other and the object, the underlying mechanisms remain unclear. To address this question, we asked subjects (n = 30 to match perceived vertical distance between the center of pressure (CoP of the thumb and index finger pads (dy of the right hand (reference hand using the same hand (test hand. The digits of reference hand were passively placed collinearly (dy = 0 mm. Subjects were then asked to exert different combinations of normal and tangential digit forces (Fn and Ftan, respectively using the reference hand and then match the memorized dy using the test hand. The reference hand exerted Ftan of thumb and index finger in either same or opposite direction. We hypothesized that, when the tangential forces of the digits are produced in opposite directions, matching error (1 would be biased toward the directions of the tangential forces, and (2 would be greater when the remembered relative contact points are matched with negligible digit force production. For the test hand, digit forces were either negligible (0.5-1 N, 0 ± 0.25 N; Experiment 1 or the same as those exerted by the reference hand (Experiment 2. Matching error was biased towards the direction of digit tangential forces: thumb CoP was placed higher than the index finger CoP when thumb and index finger Ftan were directed upward and downward, respectively, and vice versa (p < 0.001. However, matching error was not dependent on whether the reference and test hand exerted similar or different forces. We propose that the expected sensory consequence of motor commands for tangential forces in opposite directions overrides estimation of fingertip position through haptic sensory feedback.

  5. Force decomposition in robot force control

    Science.gov (United States)

    Murphy, Steve H.; Wen, John T.

    1991-01-01

    The unit inconsistency in force decomposition has motivated an investigation into the force control problem in multiple-arm manipulation. Based on physical considerations, it is argued that the force that should be controlled is the internal force at the specified frame in the payload. This force contains contributions due to both applied forces from the arms and the inertial force from the payload and the arms. A least-squares scheme free of unit inconsistency for finding this internal force is presented. The force control issue is analyzed, and an integral force feedback controller is proposed.

  6. Hybrid Quantum Mechanical and Molecular Mechanics Study of the SN2 Reaction of CCl4 + OH- in Aqueous Solution: The Potential of Mean Force, Reaction Energetics, and Rate Constants

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ting; Yin, Hongyun; Wang, Dunyou; Valiev, Marat

    2012-02-16

    The bimolecular nucleophilic substitution reaction of CCl{sub 4} and OH{sup -} in aqueous solution was investigated on the basis of a combined quantum mechanical and molecular mechanics method. A multilayered representation approach is employed to achieve high accuracy results at the CCSD(T) level of theory. The potential of mean force calculations at the DFT level and CCSD(T) level of theory yield reaction barrier heights of 22.7 and 27.9 kcal/mol, respectively. Both the solvation effects and the solvent-induced polarization effect have significant contributions to the reaction energetics, for example, the solvation effect raises the saddle point by 10.6 kcal/mol. The calculated rate constant coefficient is 8.6 x 10{sup -28} cm{sup 3} molecule{sup -1} s{sup -1} at the standard state condition, which is about 17 orders magnitude smaller than that in the gas phase. Among the four chloromethanes (CH{sub 3}Cl, CH{sub 2}Cl{sub 2}, CHCl{sub 3}, and CCl{sub 4}), CCl{sub 4} has the lowest free energy activation barrier for the reaction with OH{sup -1} in aqueous solution, confirming the trend that substitution of Cl by H in chloromethanes diminishes the reactivity.

  7. Tour de force microscopy

    OpenAIRE

    Mervyn Miles; Massimo Antognozzi; Heiko Haschke; Jamie Hobbs; Andrew Humphris; Terence McMaster

    2003-01-01

    Scanning probe microscopy (SPM) is capable of imaging synthetic polymers and biomolecular systems at sub-molecular resolution, without the need for staining or coating, in a range of environments including gas and liquid, so offering major advantages over other forms of microscopy. However, there are some limitations, which could be alleviated by (i) reducing the force interaction between the probe and specimen and (ii) increasing the rate of imaging. New developments in instrumentation from ...

  8. Technical evaluation of the electrical, instrumentation, and control design aspects of the override of containment purge valve isolation and other engineered safety feature signals for the Fort Calhoun Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hackett, D.B.

    1980-01-01

    This report documents the technical evaluation of the electrical, instrumentation, and control design aspects of the override of containment purge valve isolation and other engineered safety feature signals for the Fort Calhoun nuclear power plant. The review criteria are based on IEEE Std-279-1971 requirements for the safety signals to all purge and ventilation isolation valves. This report is supplied as part of the Selected Electrical, Instrumentation, and Control Systems Issues Program being conducted for the US Nuclear Regulatory Commission by Lawrence Livermore Laboratory.

  9. Cluster forcing

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    .g. sustainability or quality of life. The purpose of this paper is to explore how and to what extent public sector interventions that aim at forcing cluster development in industries can support sustainable development as defined in the Brundtland tradition and more recently elaborated in such concepts as eco......, Portugal and New Zealand have adopted the concept. Public sector interventions that aim to support cluster development in industries most often focus upon economic policy goals such as enhanced employment and improved productivity, but rarely emphasise broader societal policy goals relating to e...... to the automotive sector in Wales. Specifically, the paper evaluates the "Accelerates" programme initiated by the Welsh Development Agency and elaborates on how and to what extent the Accelerate programme supports the development of a sustainable automotive industry cluster. The Accelerate programme was set up...

  10. Coriolis Force

    Science.gov (United States)

    Marciuc, Daly; Solschi, Viorel

    2017-04-01

    Understanding the Coriolis effect is essential for explaining the movement of air masses and ocean currents. The lesson we propose aims to familiarize students with the manifestation of the Coriolis effect. Students are guided to build, using the GeoGebra software, a simulation of the motion of a body, related to a rotating reference system. The mathematical expression of the Coriolis force is deduced, for particular cases, and the Foucault's pendulum is presented and explained. Students have the opportunity to deepen the subject, by developing materials related to topics such as: • Global Wind Pattern • Ocean Currents • Coriolis Effect in Long Range Shooting • Finding the latitude with a Foucault Pendulum

  11. Force Development during Target-Directed Isometric Force Production in Parkinson’s Disease

    OpenAIRE

    Park, Jin-Hoon; Stelmach, George E.

    2006-01-01

    Performing various daily activities requires precise application and control of forces, which has been well addressed in neurologically healthy individuals. Recent experiments have demonstrated that in young, normal subjects generating rapid force pulses over various force amplitudes was accomplished by linearly increasing the rate of force development while keeping time to peak force approximately constant (i.e., a pulse-height control strategy). Using Parkinson’s disease (PD) patients the p...

  12. Effects of Family Structure to the Youth Labor Force Participation Rate%家庭结构对青年群体劳动参与率的影响

    Institute of Scientific and Technical Information of China (English)

    袁兴意; 齐海源

    2014-01-01

    Differences are found among the effects of family structure to different labor groups' employment participation through literature research. Based on CGSS2008 data, the article explores the influence of family structure to labor participation rate of the youth and the mechanism of the effect. Through the Probit and the IV Probit model, empirical analysis found that: Overall, the family structure of multi-generation has inhibitory effect to the youth's labor participation, while degree of influence of family structure to the male youth employment is higher than that of young women; seen from the household registration, influence of family structure to rural youth employment participation is higher than that of city youth labor force participation. Value the importance of the family characteristic differences of youth groups and carry out the employment promotion measures should be the focuses for government to help youth employment.%家庭结构对青年群体劳动参与率有影响。基于CGSS2008数据,通过Probit和IV Probit模型实证分析发现:从总体看,多代同堂的家庭结构对青年群体的劳动参与产生抑制作用,而男性青年的就业参与受家庭结构的影响程度却高于女性青年劳动参与的影响程度;从户籍看,农村青年的就业参与受家庭结构的影响程度高于城市青年劳动参与的影响程度。重视青年群体的家庭特征差异,配套实行就业促进措施,是我国政府解决青年群体就业难的着力点。

  13. The regulation of traction force in relation to cell shape and focal adhesions.

    Science.gov (United States)

    Rape, Andrew D; Guo, Wei-Hui; Wang, Yu-Li

    2011-03-01

    Mechanical forces provide critical inputs for proper cellular functions. The interplay between the generation of, and response to, mechanical forces regulate such cellular processes as differentiation, proliferation, and migration. We postulate that adherent cells respond to a number of physical and topographical factors, including cell size and shape, by detecting the magnitude and/or distribution of traction forces under different conditions. To address this possibility we introduce a new simple method for precise micropatterning of hydrogels, and then apply the technique to systematically investigate the relationship between cell geometry, focal adhesions, and traction forces in cells with a series of spread areas and aspect ratios. Contrary to previous findings, we find that traction force is not determined primarily by the cell spreading area but by the distance from cell center to the perimeter. This distance in turn controls traction forces by regulating the size of focal adhesions, such that constraining the size of focal adhesions by micropatterning can override the effect of geometry. We propose that the responses of traction forces to center-periphery distance, possibly through a positive feedback mechanism that regulates focal adhesions, provide the cell with the information on its own shape and size. A similar positive feedback control may allow cells to respond to a variety of physical or topographical signals via a unified mechanism. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Effects of Different Slopes and Pushing Force on Felling Cut Cycle and the Heart Rate of Loggers%不同坡度及作用力对伐木作业者心率及伐木锯切周期的影响

    Institute of Scientific and Technical Information of China (English)

    王立海; 潘明旭; 段铁成; 王秋实; 胡斌

    2012-01-01

    油锯伐木作业动作重复性高,劳动强度大,其强度达到重体力劳动等级(段铁成,2010).由于我国伐区作业条件不同,对油锯手的生理与心理影响较大,导致作业效率因环境变化而变化(王立海等,1995).如何使油锯手在高强度作业与不利的环境条件下保持比较高的作业效率,能保障作业人员的安全与健康,并且将林业机械设计与使用过程中融入人机工程学的理念,这些将成为科技工作者要研究的重要问题(潘明旭等,2011).%The effect of different slopes and pushing force on the heart rate of loggers in standard posture as well as on the one cutting cycle was studied in this paper. According to the questionnaire from experts, the weight of each analysis factor was obtained and AHP method was adopted to conclude the standard posture based on experiment. After comparison on the data that's got from experiment with mathematical statistics method, it was concluded that, under three different slopes, different pushing force had significant effect on the cutting cycle with standard posture. But the pushing force did not have much impact on the heart rate of the loggers at zero degree slope. Meanwhile, large pushing force and moderate pushing force did not affect the heart rate significantly when the slope is Fifteen degree, and the opposite result is with small force. At thirty degree slope, each pushing force had significant effect on the heart rate of loggers. The research may provide as a guide to the loggers in reasonable pushing force selection at different slopes, which is beneficial for the forestry production department to draft relevant operating standards in order to guarantee the working efficiency as well as the safety and physical health of loggers.

  15. Variance components in discrete force production tasks.

    Science.gov (United States)

    Varadhan, S K M; Zatsiorsky, Vladimir M; Latash, Mark L

    2010-09-01

    The study addresses the relationships between task parameters and two components of variance, "good" and "bad", during multi-finger accurate force production. The variance components are defined in the space of commands to the fingers (finger modes) and refer to variance that does ("bad") and does not ("good") affect total force. Based on an earlier study of cyclic force production, we hypothesized that speeding-up an accurate force production task would be accompanied by a drop in the regression coefficient linking the "bad" variance and force rate such that variance of the total force remains largely unaffected. We also explored changes in parameters of anticipatory synergy adjustments with speeding-up the task. The subjects produced accurate ramps of total force over different times and in different directions (force-up and force-down) while pressing with the four fingers of the right hand on individual force sensors. The two variance components were quantified, and their normalized difference was used as an index of a total force stabilizing synergy. "Good" variance scaled linearly with force magnitude and did not depend on force rate. "Bad" variance scaled linearly with force rate within each task, and the scaling coefficient did not change across tasks with different ramp times. As a result, a drop in force ramp time was associated with an increase in total force variance, unlike the results of the study of cyclic tasks. The synergy index dropped 100-200 ms prior to the first visible signs of force change. The timing and magnitude of these anticipatory synergy adjustments did not depend on the ramp time. Analysis of the data within an earlier model has shown adjustments in the variance of a timing parameter, although these adjustments were not as pronounced as in the earlier study of cyclic force production. Overall, we observed qualitative differences between the discrete and cyclic force production tasks: Speeding-up the cyclic tasks was associated with

  16. Silicon force sensor

    Science.gov (United States)

    Galambos, Paul C.; Crenshaw, Thomas B.; Nishida, Erik E.; Burnett, Damon J.; Lantz, Jeffrey W.

    2016-07-05

    The various technologies presented herein relate to a sensor for measurement of high forces and/or high load shock rate(s), whereby the sensor utilizes silicon as the sensing element. A plate of Si can have a thinned region formed therein on which can be formed a number of traces operating as a Wheatstone bridge. The brittle Si can be incorporated into a layered structure comprising ductile and/or compliant materials. The sensor can have a washer-like configuration which can be incorporated into a nut and bolt configuration, whereby tightening of the nut and bolt can facilitate application of a compressive preload upon the sensor. Upon application of an impact load on the bolt, the compressive load on the sensor can be reduced (e.g., moves towards zero-load), however the magnitude of the preload can be such that the load on the sensor does not translate to tensile stress being applied to the sensor.

  17. An Anti-Override Trip System Based on Principle of Zone Protection%一种基于区域保护原理的防越级跳闸系统

    Institute of Scientific and Technical Information of China (English)

    赵富裕

    2012-01-01

    介绍了一种基于区域保护原理的防越级跳闸系统,详细阐述了区域保护技术的基本思想及工作过程、保护闭锁信号产生及控制逻辑,并以某煤矿供电系统为例进行了实例分析.分析结果表明,基于区域保护原理的防越级跳闸系统使得井下变电所的继电保护不再依靠故障电流值和动作时间的配合,可准确快速地切除故障,实现保护选择性,大大提高了井下变电所的保护水平.%The paper introduced an anti-override trip system based on principle of zone protection, described basic idea and working process of zone protection technology and generating and control logic of blocking signal in details, and analyzed an example of power supply system of a coal mine. The analysis result shows that anti-override trip system based on principle of zone protection makes the relay protection of underground substation no longer rely on coordinate of fault current value and operating time, which can cut off fault quickly and accurately to achieve protection selectivity and improve protection level of underground substation.

  18. Malaysia and forced migration

    National Research Council Canada - National Science Library

    Arzura Idris

    2012-01-01

    This paper analyzes the phenomenon of "forced migration" in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants...

  19. Handbook of force transducers

    CERN Document Server

    Stefanescu, Dan Mihai

    2011-01-01

    Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco

  20. Malaysia and forced migration

    OpenAIRE

    Arzura Idris

    2012-01-01

    This paper analyzes the phenomenon of “forced migration” in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants. It considers forced migration as an event hosting multifaceted issues related and relevant to forced migrants and suggests that Malaysia has been preoccupied with the issue of forced migration movements. This is largely seen in various responses invoked from Malaysi...

  1. LABOR FORCE PROJECTIONS BY COLOR, 1970-80. SPECIAL LABOR FORCE REPORT NUMBER 73.

    Science.gov (United States)

    COOPER, SOPHIA; JOHNSTON, DENIS F.

    THE PROJECTIONS ARE BASED ON BUREAU OF THE CENSUS UNPUBLISHED POPULATION PROJECTIONS BY COLOR AND ON THE ASSUMPTIONS THAT PAST TRENDS IN LABOR FORCE PARTICIPATION RATES WILL CONTINUE, THAT THE SIZE OF THE ARMED FORCES WILL NOT CHANGE SIGNIFICANTLY, AND THAT THE ECONOMY WILL OPERATE AT RELATIVELY HIGH LEVELS CONSISTENT WITH AN UNEMPLOYMENT RATE OF…

  2. Knudsen forces on microcantilevers

    Science.gov (United States)

    Passian, A.; Wig, A.; Meriaudeau, F.; Ferrell, T. L.; Thundat, T.

    2002-11-01

    When two surfaces at two different temperatures are separated by a distance comparable to a mean-free path of the molecules of the ambient medium, the surfaces experience Knudsen force. This mechanical force can be important in microelectromechanical systems and in atomic force microscopy. A theoretical discussion of the magnitude of the forces and the conditions where they can be encountered is discussed. A potential application of the Knudsen force in designing a cantilever-based vacuum gauge is discussed.

  3. Imaging stability in force-feedback high-speed atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byung I., E-mail: ByungKim@boisestate.edu [Department of Physics, Boise State University, 1910 University Drive Boise, ID 83725-1570, United States of America (United States); Boehm, Ryan D. [Department of Physics, Boise State University, 1910 University Drive Boise, ID 83725-1570, United States of America (United States)

    2013-02-15

    We studied the stability of force-feedback high-speed atomic force microscopy (HSAFM) by imaging soft, hard, and biological sample surfaces at various applied forces. The HSAFM images showed sudden topographic variations of streaky fringes with a negative applied force when collected on a soft hydrocarbon film grown on a grating sample, whereas they showed stable topographic features with positive applied forces. The instability of HSAFM images with the negative applied force was explained by the transition between contact and noncontact regimes in the force–distance curve. When the grating surface was cleaned, and thus hydrophilic by removing the hydrocarbon film, enhanced imaging stability was observed at both positive and negative applied forces. The higher adhesive interaction between the tip and the surface explains the improved imaging stability. The effects of imaging rate on the imaging stability were tested on an even softer adhesive Escherichia coli biofilm deposited onto the grating structure. The biofilm and planktonic cell structures in HSAFM images were reproducible within the force deviation less than ∼0.5 nN at the imaging rate up to 0.2 s per frame, suggesting that the force-feedback HSAFM was stable for various imaging speeds in imaging softer adhesive biological samples. - Highlights: ► We investigated the imaging stability of force-feedback HSAFM. ► Stable–unstable imaging transitions rely on applied force and sample hydrophilicity. ► The stable–unstable transitions are found to be independent of imaging rate.

  4. Force-Mediated Kinetics of Single P-Selectin/Ligand Complexes Observed by Atomic Force Microscopy

    Science.gov (United States)

    Fritz, Jurgen; Katopodis, Andreas G.; Kolbinger, Frank; Anselmetti, Dario

    1998-10-01

    Leukocytes roll along the endothelium of postcapillary venules in response to inflammatory signals. Rolling under the hydrodynamic drag forces of blood flow is mediated by the interaction between selectins and their ligands across the leukocyte and endothelial cell surfaces. Here we present force-spectroscopy experiments on single complexes of P-selectin and P-selectin glycoprotein ligand-1 by atomic force microscopy to determine the intrinsic molecular properties of this dynamic adhesion process. By modeling intermolecular and intramolecular forces as well as the adhesion probability in atomic force microscopy experiments we gain information on rupture forces, elasticity, and kinetics of the P-selectin/P-selectin glycoprotein ligand-1 interaction. The complexes are able to withstand forces up to 165 pN and show a chain-like elasticity with a molecular spring constant of 5.3 pN nm-1 and a persistence length of 0.35 nm. The dissociation constant (off-rate) varies over three orders of magnitude from 0.02 s-1 under zero force up to 15 s-1 under external applied forces. Rupture force and lifetime of the complexes are not constant, but directly depend on the applied force per unit time, which is a product of the intrinsic molecular elasticity and the external pulling velocity. The high strength of binding combined with force-dependent rate constants and high molecular elasticity are tailored to support physiological leukocyte rolling.

  5. Employment: Labor Force Status (1983-2012)

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Civilian labor force data consists of the number of employed persons, the number of unemployed persons, an unemployment rate and the total count of both employed and...

  6. Wall force produced during disruptions

    Science.gov (United States)

    Strauss, H.; Paccagnella, R.; Breslau, J.

    2009-11-01

    The study of disruptions is of great importance for ITER. Previous work on disruptions [1] is extended to compute toroidally asymmetric wall force in ITER, using the M3D code. The disruptions are produced by n = 1 resistive wall modes or external kink modes. A thin wall resistive boundary model is used to calculate the wall forces. The symmetric wall force, produced by a VDE, and the asymmetric wall force, produced by n = 1 modes, are comparable in magnitude. It is found that the asymmetric and axisymmetric forces scale with the growth rate of the instability multiplied by the square of the current divided by magnetic field. A similar scaling was reported for VDEs in JET [2]. Numerically, the study of disruptions is very challenging. In the M3D extended MHD code, dealiasing was applied in the toroidal direction. Advection terms were treated with a numerical upwind method. These techniques provided sufficient numerical stability to simulate entire disruption events. [4pt] [1] R. Paccagnella, H. R. Strauss, and J. Breslau, Nucl. Fusion (2009) 49 035003. [2] V. Riccardo, T. C. Hender, P. J. Lomas, et al., Plasma Phys. Control. Fusion (2004)

  7. Malaysia and forced migration

    Directory of Open Access Journals (Sweden)

    Arzura Idris

    2012-06-01

    Full Text Available This paper analyzes the phenomenon of “forced migration” in Malaysia. It examines the nature of forced migration, the challenges faced by Malaysia, the policy responses and their impact on the country and upon the forced migrants. It considers forced migration as an event hosting multifaceted issues related and relevant to forced migrants and suggests that Malaysia has been preoccupied with the issue of forced migration movements. This is largely seen in various responses invoked from Malaysia due to “south-south forced migration movements.” These responses are, however, inadequate in terms of commitment to the international refugee regime. While Malaysia did respond to economic and migration challenges, the paper asserts that such efforts are futile if she ignores issues critical to forced migrants.

  8. Kinetic Ductility and Force-Spike Resistance of Proteins from Single-Molecule Force Spectroscopy.

    Science.gov (United States)

    Cossio, Pilar; Hummer, Gerhard; Szabo, Attila

    2016-08-23

    Ductile materials can absorb spikes in mechanical force, whereas brittle ones fail catastrophically. Here we develop a theory to quantify the kinetic ductility of single molecules from force spectroscopy experiments, relating force-spike resistance to the differential responses of the intact protein and the unfolding transition state to an applied mechanical force. We introduce a class of unistable one-dimensional potential surfaces that encompass previous models as special cases and continuously cover the entire range from ductile to brittle. Compact analytic expressions for force-dependent rates and rupture-force distributions allow us to analyze force-clamp and force-ramp pulling experiments. We find that the force-transmitting protein domains of filamin and titin are kinetically ductile when pulled from their two termini, making them resistant to force spikes. For the mechanostable muscle protein titin, a highly ductile model reconciles data over 10 orders of magnitude in force loading rate from experiment and simulation. Copyright © 2016 Biophysical Society. All rights reserved.

  9. Fluid force transducer

    Science.gov (United States)

    Jendrzejczyk, Joseph A.

    1982-01-01

    An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.

  10. Hydrophobic Forces in Flotation

    OpenAIRE

    Pazhianur, Rajesh R

    1999-01-01

    An atomic force microscope (AFM) has been used to conduct force measurements to better understand the role of hydrophobic forces in flotation. The force measurements were conducted between a flat mineral substrate and a hydrophobic glass sphere in aqueous solutions. It is assumed that the hydrophobic glass sphere may simulate the behavior of air bubbles during flotation. The results may provide information relevant to the bubble-particle interactions occurring during flotation. The glass ...

  11. 防喘振控制中的过程解耦与超驰控制分析%Analysis for Process Decoupling and Override Control Based on Anti-surge Control

    Institute of Scientific and Technical Information of China (English)

    蔡吉明; 方宏昌

    2011-01-01

    介绍一种压缩机防喘振控制中的过程解耦控制方案的应用。讨论了机组防喘振控制方案的具体实现;并重点分析了过程控制和防喘振解耦功能的相关设计,阐述了过程控制和防喘振控制的超弛控制及整个控制方案的系统构建。%The application of a process decoupling control design based on anti-surge control for centrifugal compressor is introduced, detailed implementation of anti-surge control scheme is discussed, relative design of process control and anti-surge decoupling functionality is stressed, and the system configuration for override control of process and anti-surge, as well as integration, for all control scenario are discussed.

  12. Debunking Coriolis Force Myths

    Science.gov (United States)

    Shakur, Asif

    2014-01-01

    Much has been written and debated about the Coriolis force. Unfortunately, this has done little to demystify the paradoxes surrounding this fictitious force invoked by an observer in a rotating frame of reference. It is the purpose of this article to make another valiant attempt to slay the dragon of the Coriolis force! This will be done without…

  13. Forces in General Relativity

    Science.gov (United States)

    Ridgely, Charles T.

    2010-01-01

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced…

  14. Forces in General Relativity

    Science.gov (United States)

    Ridgely, Charles T.

    2010-01-01

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced…

  15. Muscle size, neuromuscular activation, and rapid force characteristics in elderly men and women

    DEFF Research Database (Denmark)

    Suetta, C; Aagaard, P; Magnusson, S P

    2007-01-01

    quadriceps muscle cross-sectional area (LCSA), contractile rate of force development (RFD, Delta force/Delta time), impulse (integral force dt), muscle activation deficit (interpolated twitch technique), maximal neuromuscular activity [electromyogram (EMG)], and antagonist muscle coactivation in elderly men...

  16. Reactivation of developmentally silenced globin genes by forced chromatin looping.

    Science.gov (United States)

    Deng, Wulan; Rupon, Jeremy W; Krivega, Ivan; Breda, Laura; Motta, Irene; Jahn, Kristen S; Reik, Andreas; Gregory, Philip D; Rivella, Stefano; Dean, Ann; Blobel, Gerd A

    2014-08-14

    Distal enhancers commonly contact target promoters via chromatin looping. In erythroid cells, the locus control region (LCR) contacts β-type globin genes in a developmental stage-specific manner to stimulate transcription. Previously, we induced LCR-promoter looping by tethering the self-association domain (SA) of Ldb1 to the β-globin promoter via artificial zinc fingers. Here, we show that targeting the SA to a developmentally silenced embryonic globin gene in adult murine erythroblasts triggers its transcriptional reactivation. This activity depends on the LCR, consistent with an LCR-promoter looping mechanism. Strikingly, targeting the SA to the fetal γ-globin promoter in primary adult human erythroblasts increases γ-globin promoter-LCR contacts, stimulating transcription to approximately 85% of total β-globin synthesis, with a reciprocal reduction in adult β-globin expression. Our findings demonstrate that forced chromatin looping can override a stringent developmental gene expression program and suggest a novel approach to control the balance of globin gene transcription for therapeutic applications.

  17. Force-Time Curve Comparison Between Weightlifting Derivatives.

    Science.gov (United States)

    Suchomel, Timothy J; Sole, Christopher J

    2016-08-24

    The force production characteristics of three weightlifting derivatives were examined by comparing the force-time curves of each exercise. Sixteen resistance-trained men performed repetitions of the hang power clean (HPC), jump shrug (JS), and hang high pull (HHP) on a force platform at several relative loads. Relative peak force (PFRel), relative impulse (IMPRel), peak rate of force development (PRFD), and time normalized force-time curves of each exercise were compared. The JS produced greater PFRel compared to the HPC (p force-time profiles were similar during the first 75-80% of the movement; however, the JS produced markedly different force-time characteristics in the final 20-25% of the movement. The JS produced superior force production characteristics, namely PFRel, IMPRel, and PRFD, as well as a unique force-time profile, compared to the HPC and HHP across several loads.

  18. Quantum fictitious forces

    DEFF Research Database (Denmark)

    Bialynicki-Birula, I; Cirone, M.A.; Dahl, Jens Peder

    2002-01-01

    ) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number......We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii...... of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: "Force without force"....

  19. Quantum fictitious forces

    DEFF Research Database (Denmark)

    Bialynicki-Birula, I; Cirone, M.A.; Dahl, Jens Peder

    2002-01-01

    We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii......) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number...... of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: "Force without force"....

  20. Quantum fictitious forces

    Energy Technology Data Exchange (ETDEWEB)

    Bialynicki-Birula, I. [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Abt. fuer Quantenphysik, Univ. Ulm, Ulm (Germany); Cirone, M.A.; Straub, F.; Schleich, W.P. [Abt. fuer Quantenphysik, Univ. Ulm, Ulm (Germany); Dahl, J.P. [Abt. fuer Quantenphysik, Univ. Ulm, Ulm (Germany); Chemical Physics, Dept. of Chemistry, Technical Univ. of Denmark, Lyngby (Denmark); Seligman, T.H. [Centro de Ciencias Fisicas, Univ. of Mexico (UNAM), Cuernavaca (Mexico)

    2002-07-01

    We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: ''Force without force''. (orig.)

  1. Forces in molecules.

    Science.gov (United States)

    Hernández-Trujillo, Jesús; Cortés-Guzmán, Fernando; Fang, De-Chai; Bader, Richard F W

    2007-01-01

    Chemistry is determined by the electrostatic forces acting within a collection of nuclei and electrons. The attraction of the nuclei for the electrons is the only attractive force in a molecule and is the force responsible for the bonding between atoms. This is the attractive force acting on the electrons in the Ehrenfest force and on the nuclei in the Feynman force, one that is countered by the repulsion between the electrons in the former and by the repulsion between the nuclei in the latter. The virial theorem relates these forces to the energy changes resulting from interactions between atoms. All bonding, as signified by the presence of a bond path, has a common origin in terms of the mechanics determined by the Ehrenfest, Feynman and virial theorems. This paper is concerned in particular with the mechanics of interaction encountered in what are classically described as 'nonbonded interactions'--are atoms that 'touch' bonded or repelling one another?

  2. High-speed atomic force microscopy: imaging and force spectroscopy.

    Science.gov (United States)

    Eghiaian, Frédéric; Rico, Felix; Colom, Adai; Casuso, Ignacio; Scheuring, Simon

    2014-10-01

    Atomic force microscopy (AFM) is the type of scanning probe microscopy that is probably best adapted for imaging biological samples in physiological conditions with submolecular lateral and vertical resolution. In addition, AFM is a method of choice to study the mechanical unfolding of proteins or for cellular force spectroscopy. In spite of 28 years of successful use in biological sciences, AFM is far from enjoying the same popularity as electron and fluorescence microscopy. The advent of high-speed atomic force microscopy (HS-AFM), about 10 years ago, has provided unprecedented insights into the dynamics of membrane proteins and molecular machines from the single-molecule to the cellular level. HS-AFM imaging at nanometer-resolution and sub-second frame rate may open novel research fields depicting dynamic events at the single bio-molecule level. As such, HS-AFM is complementary to other structural and cellular biology techniques, and hopefully will gain acceptance from researchers from various fields. In this review we describe some of the most recent reports of dynamic bio-molecular imaging by HS-AFM, as well as the advent of high-speed force spectroscopy (HS-FS) for single protein unfolding.

  3. An Analysis of the Differentials of the Rates of Return to Human Capital between Urban and Rural Labor Force in China-Analysis Based on Data of Chinese General Social Survey%中国人力资本回报率的城乡差异--基于中国综合社会调查数据的分析

    Institute of Scientific and Technical Information of China (English)

    孟凡强; 熊家财

    2015-01-01

    通过教育回报率、任期回报率和其他经验回报率三个方面考察中国人力资本回报率的城乡差异,研究结果发现:(1)受教育年限对于城镇劳动力和农村劳动力的工资水平都有显著的正向影响,现职任职期和其他工作经验对于城镇劳动力的工资水平都有显著的正向影响,但对农村劳动力的工资水平均不存在显著影响,这说明提高受教育年限是提高农村劳动力工资水平的主要途径。(2)人力资本回报率存在显著的城乡差异,城乡劳动力教育回报率的差异在2%左右,任期回报率的差异也在2%左右,而其他经验回报率的差异在1%左右。人力资本回报率的城乡差异违背了劳动力市场的竞争性,成为劳动力市场进一步完善的阻碍。%Through the analysis on the rates of return to schooling,tenure and other experience,the differentials of the rates of re-turn to human capital between urban and rural labor force in China are examined.The evidence confirms that:(1 )the years of schooling has a significant positive impact on the wages of urban and rural labor force.Tenure and other experi-ence also have significant positive influence on wages of the urban labor force,but not on the wages of rural labor force. So extension of the years of schooling is the main way to raise the wage level of the rural labor force.(2)There exist sig-nificant differences between urban and rural labor force as regard to the rate of return to human capital,as the gap is a-bout 2% in the rates of return schooling,about 2% in tenure and 1% in other experience.The differences go against with the competition of the labor market and will be the obstacles to the improvement of labor market.

  4. Intramuscular fiber conduction velocity, isometric force and explosive performance.

    Science.gov (United States)

    Methenitis, Spyridon; Terzis, Gerasimos; Zaras, Nikolaos; Stasinaki, Angeliki-Nikoletta; Karandreas, Nikolaos

    2016-06-01

    Conduction of electrical signals along the surface of muscle fibers is acknowledged as an essential neuromuscular component which is linked with muscle force production. However, it remains unclear whether muscle fiber conduction velocity (MFCV) is also linked with explosive performance. The aim of the present study was to investigate the relationship between vastus lateralis MFCV and countermovement jumping performance, the rate of force development and maximum isometric force. Fifteen moderately-trained young females performed countermovement jumps as well as an isometric leg press test in order to determine the rate of force development and maximum isometric force. Vastus lateralis MFCV was measured with intramuscular microelectrodes at rest on a different occasion. Maximum MFCV was significantly correlated with maximum isometric force (r = 0.66, p rate of force development at 100 ms, 150 ms, 200 ms, and 250 ms (r = 0.85, r = 0.89, r = 0.91, r = 0.92, respectively, p rate of force development than with maximum isometric leg press force. Lower, but significant correlations were found between mean MFCV and countermovement jump power (r = 0.65, p rate of force development than with isometric force, perhaps because conduction velocity is higher in the larger and fastest muscle fibers which are recognized to contribute to explosive actions.

  5. Interstate Migrant Education Task Force: Migrant Health.

    Science.gov (United States)

    Education Commission of the States, Denver, CO.

    Because ill-clothed, sick, or hungry migrant children learn poorly, the Task Force has emphasized the migrant health situation in 1979. Migrant workers have a 33% shorter life expectancy, a 25% higher infant mortality rate, and a 25% higher death rate from tuberculosis and other communicable diseases than the national average. Common among…

  6. Relativistic Linear Restoring Force

    Science.gov (United States)

    Clark, D.; Franklin, J.; Mann, N.

    2012-01-01

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…

  7. Intermolecular and surface forces

    CERN Document Server

    Israelachvili, Jacob N

    2011-01-01

    This reference describes the role of various intermolecular and interparticle forces in determining the properties of simple systems such as gases, liquids and solids, with a special focus on more complex colloidal, polymeric and biological systems. The book provides a thorough foundation in theories and concepts of intermolecular forces, allowing researchers and students to recognize which forces are important in any particular system, as well as how to control these forces. This third edition is expanded into three sections and contains five new chapters over the previous edition.· starts fr

  8. Force induced DNA melting

    Energy Technology Data Exchange (ETDEWEB)

    Santosh, Mogurampelly; Maiti, Prabal K [Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore-12 (India)], E-mail: santosh@physics.iisc.ernet.in, E-mail: maiti@physics.iisc.ernet.in

    2009-01-21

    When pulled along the axis, double-strand DNA undergoes a large conformational change and elongates by roughly twice its initial contour length at a pulling force of about 70 pN. The transition to this highly overstretched form of DNA is very cooperative. Applying a force perpendicular to the DNA axis (unzipping), double-strand DNA can also be separated into two single-stranded DNA, this being a fundamental process in DNA replication. We study the DNA overstretching and unzipping transition using fully atomistic molecular dynamics (MD) simulations and argue that the conformational changes of double-strand DNA associated with either of the above mentioned processes can be viewed as force induced DNA melting. As the force at one end of the DNA is increased the DNA starts melting abruptly/smoothly above a critical force depending on the pulling direction. The critical force f{sub m}, at which DNA melts completely decreases as the temperature of the system is increased. The melting force in the case of unzipping is smaller compared to the melting force when the DNA is pulled along the helical axis. In the case of melting through unzipping, the double-strand separation has jumps which correspond to the different energy minima arising due to sequence of different base pairs. The fraction of Watson-Crick base pair hydrogen bond breaking as a function of force does not show smooth and continuous behavior and consists of plateaus followed by sharp jumps.

  9. Theory of intermolecular forces

    CERN Document Server

    Margenau, H; Ter Haar, D

    1971-01-01

    Theory of Intermolecular Forces deals with the exposition of the principles and techniques of the theory of intermolecular forces. The text focuses on the basic theory and surveys other aspects, with particular attention to relevant experiments. The initial chapters introduce the reader to the history of intermolecular forces. Succeeding chapters present topics on short, intermediate, and long range atomic interactions; properties of Coulomb interactions; shape-dependent forces between molecules; and physical adsorption. The book will be of good use to experts and students of quantum mechanics

  10. Attainment and retention of force moderation following laparoscopic resection training with visual force feedback.

    Science.gov (United States)

    Hernandez, Rafael; Onar-Thomas, Arzu; Travascio, Francesco; Asfour, Shihab

    2017-04-14

    Laparoscopic training with visual force feedback can lead to immediate improvements in force moderation. However, the long-term retention of this kind of learning and its potential decay are yet unclear. A laparoscopic resection task and force sensing apparatus were designed to assess the benefits of visual force feedback training. Twenty-two male university students with no previous experience in laparoscopy underwent relevant FLS proficiency training. Participants were randomly assigned to either a control or treatment group. Both groups trained on the task for 2 weeks as follows: initial baseline, sixteen training trials, and post-test immediately after. The treatment group had visual force feedback during training, whereas the control group did not. Participants then performed four weekly test trials to assess long-term retention of training. Outcomes recorded were maximum pulling and pushing forces, completion time, and rated task difficulty. Extreme maximum pulling force values were tapered throughout both the training and retention periods. Average maximum pushing forces were significantly lowered towards the end of training and during retention period. No significant decay of applied force learning was found during the 4-week retention period. Completion time and rated task difficulty were higher during training, but results indicate that the difference eventually fades during the retention period. Significant differences in aptitude across participants were found. Visual force feedback training improves on certain aspects of force moderation in a laparoscopic resection task. Results suggest that with enough training there is no significant decay of learning within the first month of the retention period. It is essential to account for differences in aptitude between individuals in this type of longitudinal research. This study shows how an inexpensive force measuring system can be used with an FLS Trainer System after some retrofitting. Surgical

  11. Rates of acute respiratory illnesses of infectious and allergic etiologies after permanent changes of duty assignments, active component, U.S. Army, Air Force, and Marine Corps, January 2005-September 2015.

    Science.gov (United States)

    Brundage, John F; Taubman, Stephen B; Clark, Leslie L

    2015-11-01

    Throughout history, acute respiratory illnesses (ARIs) have disproportionately affected military populations, particularly those in recruit training camps. A similar dynamic can affect non-trainee military settings. When military members are reassigned, they often develop ARIs within the first weeks of their arrivals at their new assignments. To assess the natures and magnitudes of the risks associated with new assignments, this analysis compared the experiences of service members within their first full calendar months at new assignments and during the same months at the same locations 1 year later. The results do not support the hypothesis that ARIs of infectious etiologies consistently occur more frequently soon after arriving at new assignments compared to 1 year later at the same locations. In contrast, during two-thirds of the 117 months considered here, rates of ARIs of presumed allergic etiologies (e.g., allergic rhinitis, asthma) were higher during the first months of new assignments compared to 1 year later. The limitations of the study methodology as well as the possible implications of the findings are discussed.

  12. Ecology-driven stereotypes override race stereotypes

    Science.gov (United States)

    Williams, Keelah E. G.; Sng, Oliver; Neuberg, Steven L.

    2016-01-01

    Why do race stereotypes take the forms they do? Life history theory posits that features of the ecology shape individuals’ behavior. Harsh and unpredictable (“desperate”) ecologies induce fast strategy behaviors such as impulsivity, whereas resource-sufficient and predictable (“hopeful”) ecologies induce slow strategy behaviors such as future focus. We suggest that individuals possess a lay understanding of ecology’s influence on behavior, resulting in ecology-driven stereotypes. Importantly, because race is confounded with ecology in the United States, we propose that Americans’ stereotypes about racial groups actually reflect stereotypes about these groups’ presumed home ecologies. Study 1 demonstrates that individuals hold ecology stereotypes, stereotyping people from desperate ecologies as possessing faster life history strategies than people from hopeful ecologies. Studies 2–4 rule out alternative explanations for those findings. Study 5, which independently manipulates race and ecology information, demonstrates that when provided with information about a person’s race (but not ecology), individuals’ inferences about blacks track stereotypes of people from desperate ecologies, and individuals’ inferences about whites track stereotypes of people from hopeful ecologies. However, when provided with information about both the race and ecology of others, individuals’ inferences reflect the targets’ ecology rather than their race: black and white targets from desperate ecologies are stereotyped as equally fast life history strategists, whereas black and white targets from hopeful ecologies are stereotyped as equally slow life history strategists. These findings suggest that the content of several predominant race stereotypes may not reflect race, per se, but rather inferences about how one’s ecology influences behavior. PMID:26712013

  13. Ecology-driven stereotypes override race stereotypes.

    Science.gov (United States)

    Williams, Keelah E G; Sng, Oliver; Neuberg, Steven L

    2016-01-12

    Why do race stereotypes take the forms they do? Life history theory posits that features of the ecology shape individuals' behavior. Harsh and unpredictable ("desperate") ecologies induce fast strategy behaviors such as impulsivity, whereas resource-sufficient and predictable ("hopeful") ecologies induce slow strategy behaviors such as future focus. We suggest that individuals possess a lay understanding of ecology's influence on behavior, resulting in ecology-driven stereotypes. Importantly, because race is confounded with ecology in the United States, we propose that Americans' stereotypes about racial groups actually reflect stereotypes about these groups' presumed home ecologies. Study 1 demonstrates that individuals hold ecology stereotypes, stereotyping people from desperate ecologies as possessing faster life history strategies than people from hopeful ecologies. Studies 2-4 rule out alternative explanations for those findings. Study 5, which independently manipulates race and ecology information, demonstrates that when provided with information about a person's race (but not ecology), individuals' inferences about blacks track stereotypes of people from desperate ecologies, and individuals' inferences about whites track stereotypes of people from hopeful ecologies. However, when provided with information about both the race and ecology of others, individuals' inferences reflect the targets' ecology rather than their race: black and white targets from desperate ecologies are stereotyped as equally fast life history strategists, whereas black and white targets from hopeful ecologies are stereotyped as equally slow life history strategists. These findings suggest that the content of several predominant race stereotypes may not reflect race, per se, but rather inferences about how one's ecology influences behavior.

  14. Dark Dunes Over-riding Bright Dunes

    Science.gov (United States)

    2000-01-01

    Some martian sand dunes may be more active than others. In this picture, wind has caused the dark and somewhat crescent-shaped dunes to advance toward the lower left. While their movement cannot actually be seen in this April 1998snapshot, the location of their steepest slopes--their slip faces--on their southwestern sides indicates the direction of movement. Oddly, these dark dunes have moved across and partly cover sets of smaller, bright ridges that also formed by wind action.This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image illustrates an intriguing martian 'find.' Strangely, the two dune types have different shapes and a different relative brightness. There are two explanations for the relationship seen here, and neither can be distinguished as 'the answer'--(1) it is possible that the brighter dunes are old and cemented, and represent some ancient wind activity, whereas the dark dunes are modern and are marching across the older, 'fossilized' dune forms, or (2) the bright dunes are composed of grains that are much larger or more dense than those that compose the dark dunes. In the latter scenario, the bright dunes move more slowly and are over-taken by the dark dunes because their grains are harder to transport. An interpretation involving larger or denser grains is consistent with the small size and even-spacing of the bright dunes, as well, but usually on Earth such features occur on the surfaces of larger, finer-grained dunes, not under them. The actual composition of either the bright or dark materials are unknown. This example is located on the floor of an impact crater in western Arabia Terra at 10.7oN, 351.0oW. The picture is illuminated from the right.

  15. Dark Streaks Over-riding Inactive Dunes

    Science.gov (United States)

    2000-01-01

    Not all sand dunes on Mars are active in the modern martian environment. This example from the Lycus Sulci (Olympus Mons'aureole') region shows a case where small windblown dunes at the base of a slope have been over-ridden by more recent dark streaks (arrows). The dark streaks are most likely caused by what geologists call mass wasting or mass movement (landslides and avalanches are mass movements). Dark slope streaks such as these are common in dustier regions of Mars, and they appear to result from movement of extremely dry dust or sand in an almost fluidlike manner down a slope. This movement disrupts the bright dust coating on the surface and thus appears darker than the surrounding terrain.In this case, the dark slope streaks have moved up and over the dunes at the bottom of the slope, indicating that the process that moves sediment down the slope is more active (that is, it has occurred more recently and hence is more likely to occur) in the modern environment than is the movement of dunes and ripples at this location on Mars. The dunes, in fact, are probably mantled by dust. This October 1997 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture is illuminated from the left and located near 31.6oN, 134.0oW.

  16. Ecology-driven stereotypes override race stereotypes

    OpenAIRE

    Williams, Keelah E. G.; Sng, Oliver; Neuberg, Steven L.

    2015-01-01

    Ecological features shape people’s goals, strategies, and behaviors. Our research suggests that social perceivers possess a lay understanding of ecology’s influence on behavior, resulting in ecology-driven stereotypes. Moreover, because race is confounded with ecology in the United States, Americans’ stereotypes about racial groups may actually reflect their stereotypes about these groups’ presumed home ecologies. In a series of studies, we demonstrate that (i) individuals possess ecology-dri...

  17. Climate forcings and feedbacks

    Science.gov (United States)

    Hansen, James

    1993-01-01

    Global temperature has increased significantly during the past century. Understanding the causes of observed global temperature change is impossible in the absence of adequate monitoring of changes in global climate forcings and radiative feedbacks. Climate forcings are changes imposed on the planet's energy balance, such as change of incoming sunlight or a human-induced change of surface properties due to deforestation. Radiative feedbacks are radiative changes induced by climate change, such as alteration of cloud properties or the extent of sea ice. Monitoring of global climate forcings and feedbacks, if sufficiently precise and long-term, can provide a very strong constraint on interpretation of observed temperature change. Such monitoring is essential to eliminate uncertainties about the relative importance of various climate change mechanisms including tropospheric sulfate aerosols from burning of coal and oil smoke from slash and burn agriculture, changes of solar irradiance changes of several greenhouse gases, and many other mechanisms. The considerable variability of observed temperature, together with evidence that a substantial portion of this variability is unforced indicates that observations of climate forcings and feedbacks must be continued for decades. Since the climate system responds to the time integral of the forcing, a further requirement is that the observations be carried out continuously. However, precise observations of forcings and feedbacks will also be able to provide valuable conclusions on shorter time scales. For example, knowledge of the climate forcing by increasing CFC's relative to the forcing by changing ozone is important to policymakers, as is information on the forcing by CO2 relative to the forcing by sulfate aerosols. It will also be possible to obtain valuable tests of climate models on short time scales, if there is precise monitoring of all forcings and feedbacks during and after events such as a large volcanic eruption

  18. Effects of orthodontic forces on pulp tissue

    Directory of Open Access Journals (Sweden)

    Pinandi Sri Pudyani

    2006-09-01

    Full Text Available Numerous researches on pulp tissue changes caused by orthodontic forces have been performed, among others are: pulp angiogenesis, pulp tissue respiration rate, alkaline phosphatase and aspartate aminotransferase enzyme activities; micro vascular response inside the pulp and the effect of dental movement i.e. extrusion, intrusion, and torque. The result is still controversial, as some researchers claim that orthodontic force has a negative effect, others deny by saying there is no such effect on pulp tissue.

  19. Mechanics of forced unfolding of proteins.

    Science.gov (United States)

    Su, Tianxiang; Purohit, Prashant K

    2009-07-01

    We describe and solve a two-state kinetic model for the forced unfolding of proteins. The protein oligomer is modeled as a heterogeneous, freely jointed chain with two possible values of Kuhn length and contour length representing its folded and unfolded configurations. We obtain analytical solutions for the force-extension response of the protein oligomer for different types of loading conditions. We fit the analytical solutions for constant-velocity pulling to the force-extension data for ubiquitin and fibrinogen and obtain model parameters, such as Kuhn lengths and kinetic coefficients, for both proteins. We then predict their response under a linearly increasing force and find that our solutions for ubiquitin are consistent with a different set of experiments. Our calculations suggest that the refolding rate of proteins at low forces is several orders larger than the unfolding rate, and neglecting it can lead to lower predictions for the unfolding force, especially at high stretching velocities. By accounting for the refolding of proteins we obtain a critical force below which equilibrium is biased in favor of the folded state. Our calculations also suggest new methods to determine the distance of the transition state from the energy wells representing the folded and unfolded states of a protein.

  20. Radiation Reaction Force on a Particle

    OpenAIRE

    Fearn, H.; Bengtsson, J.

    2012-01-01

    The Abrahamn Lorentz radiation reaction force term, with da/dt, derived in text books is shown to be incomplete. We show that, with the addition of a term, the classical radiation reaction force can be generalized to the relativistic force expression. This addition is the Poynting Robertson term, seen mostly in astrophysics and usually missing from texts in electromagnetism. With this term added, it takes into account the rate of change of mass dm/dt of the particle and makes the generalizati...

  1. Elementary Particles and Forces.

    Science.gov (United States)

    Quigg, Chris

    1985-01-01

    Discusses subatomic particles (quarks, leptons, and others) revealed by higher accelerator energies. A connection between forces at this subatomic level has been established, and prospects are good for a description of forces that encompass binding atomic nuclei. Colors, fundamental interactions, screening, camouflage, electroweak symmetry, and…

  2. Forces in yeast flocculation.

    Science.gov (United States)

    El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Vincent, Stéphane P; Abellán Flos, Marta; Hols, Pascal; Lipke, Peter N; Dufrêne, Yves F

    2015-02-07

    In the baker's yeast Saccharomyces cerevisiae, cell-cell adhesion ("flocculation") is conferred by a family of lectin-like proteins known as the flocculin (Flo) proteins. Knowledge of the adhesive and mechanical properties of flocculins is important for understanding the mechanisms of yeast adhesion, and may help controlling yeast behaviour in biotechnology. We use single-molecule and single-cell atomic force microscopy (AFM) to explore the nanoscale forces engaged in yeast flocculation, focusing on the role of Flo1 as a prototype of flocculins. Using AFM tips labelled with mannose, we detect single flocculins on Flo1-expressing cells, showing they are widely exposed on the cell surface. When subjected to force, individual Flo1 proteins display two distinct force responses, i.e. weak lectin binding forces and strong unfolding forces reflecting the force-induced extension of hydrophobic tandem repeats. We demonstrate that cell-cell adhesion bonds also involve multiple weak lectin interactions together with strong unfolding forces, both associated with Flo1 molecules. Single-molecule and single-cell data correlate with microscale cell adhesion behaviour, suggesting strongly that Flo1 mechanics is critical for yeast flocculation. These results favour a model in which not only weak lectin-sugar interactions are involved in yeast flocculation but also strong hydrophobic interactions resulting from protein unfolding.

  3. Polarizable force fields.

    Science.gov (United States)

    Antila, Hanne S; Salonen, Emppu

    2013-01-01

    This chapter provides an overview of the most common methods for including an explicit description of electronic polarization in molecular mechanics force fields: the induced point dipole, shell, and fluctuating charge models. The importance of including polarization effects in biomolecular simulations is discussed, and some of the most important achievements in the development of polarizable biomolecular force fields to date are highlighted.

  4. Limitations of constant-force-feedback experiments.

    Science.gov (United States)

    Elms, Phillip J; Chodera, John D; Bustamante, Carlos J; Marqusee, Susan

    2012-10-03

    Single-molecule force spectroscopy has provided important insights into the properties and mechanisms of biological molecules and systems. A common experiment is to measure the force dependence of conformational changes at equilibrium. Here, we demonstrate that the commonly used technique of force feedback has severe limitations when used to evaluate rapid macromolecular conformational transitions. By comparing the force-dependent dynamics of three major classes of macromolecules (DNA, RNA, and protein) using both a constant-force-feedback and a constant-trap-position technique, we demonstrate a problem in force-feedback experiments. The finite response time of the instrument's force feedback can modify the behavior of the molecule, leading to errors in the reported parameters, such as the rate constants and the distance to the transition state, for the conformational transitions. We elucidate the causes of this problem and provide a simple test to identify and evaluate the magnitude of the effect. We recommend avoiding the use of constant force feedback as a method to study rapid conformational changes in macromolecules.

  5. Keeping Special Forces Special: Regional Proficiency in Special Forces

    Science.gov (United States)

    2011-12-01

    than one month IOT allow Soldiers to listen to the language, conduct travel/recon etc. —Special Forces Soldier294 Immersion is the third method by...incentive lower. Conversely, a person with a lower interest in regional proficiency would rate the incentive higher. Variable Mean Std Dev Regional...Variable Mean Std Dev Regional Proficiency Interest 6.29 .99 Command Environment Value 4.41 1.62 PDSI 2.54 1.60 Promotion 2.92 1.62 153

  6. The Total Force Policy and Effective Force

    Science.gov (United States)

    2006-05-31

    analysis.” 23 Roald Dahl, Charlie and the Chocolate Factory , (New York: Pequin Books, 1964), 87, 150. Mr. Dahl’s image of the everlasting gobstopper...Office of the Chief, Army Reserve, 1997. Dahl, Roald. Charlie and the Chocolate Factory . Penguin Books: New York, 1964. Feaver, Peter D. Armed Servants...knot24 that must be untied in order to prove relevance as a military force. Of course, we know the end of these ancient and modern stories. Charlie

  7. Air Bag Momentum Force Including Aspiration

    Directory of Open Access Journals (Sweden)

    Guy Nusholtz

    1995-01-01

    Full Text Available A gas-jet momentum force drives the air bag into position during a crash. The magnitude of this force can change as a result of aspiration. To determine the potential magnitude of the effect on the momentum force and mass flow rate in an aspirated system, a series of experiments and simulations of those experiments was conducted. The simulation consists of a two-dimensional unsteady isentropic CFD model with special “infinite boundaries”. One of the difficulties in simulating the gas-jet behavior is determining the mass flow rate. To improve the reliability of the mass flow rate input to the simulation, a sampling procedure involving multiple tests was used, and an average of the tests was adopted.

  8. OOTW Force Design Tools

    Energy Technology Data Exchange (ETDEWEB)

    Bell, R.E.; Hartley, D.S.III; Packard, S.L.

    1999-05-01

    This report documents refined requirements for tools to aid the process of force design in Operations Other Than War (OOTWs). It recommends actions for the creation of one tool and work on other tools relating to mission planning. It also identifies the governmental agencies and commands with interests in each tool, from whom should come the user advisory groups overseeing the respective tool development activities. The understanding of OOTWs and their analytical support requirements has matured to the point where action can be taken in three areas: force design, collaborative analysis, and impact analysis. While the nature of the action and the length of time before complete results can be expected depends on the area, in each case the action should begin immediately. Force design for OOTWs is not a technically difficult process. Like force design for combat operations, it is a process of matching the capabilities of forces against the specified and implied tasks of the operation, considering the constraints of logistics, transport and force availabilities. However, there is a critical difference that restricts the usefulness of combat force design tools for OOTWs: the combat tools are built to infer non-combat capability requirements from combat capability requirements and cannot reverse the direction of the inference, as is required for OOTWs. Recently, OOTWs have played a larger role in force assessment, system effectiveness and tradeoff analysis, and concept and doctrine development and analysis. In the first Quadrennial Defense Review (QDR), each of the Services created its own OOTW force design tool. Unfortunately, the tools address different parts of the problem and do not coordinate the use of competing capabilities. These tools satisfied the immediate requirements of the QDR, but do not provide a long-term cost-effective solution.

  9. Light forces in ultracold photoassociation

    CERN Document Server

    Gómez, E; Lett, P D; Tiesinga, E; Turner, L D

    2006-01-01

    We study the time-resolved photoassociation of ultracold sodium in an optical dipole trap. The photoassociation laser excites pairs of atoms to molecular states of large total angular momentum at high intensities (above 20 kW/cm$^{2}$). Such transitions are generally suppressed at ultracold temperatures by the centrifugal barriers for high partial waves. Time-resolved ionization measurements reveal that the atoms are accelerated by the dipole potential of the photoassociation beam. We change the collision energy by varying the potential depth, and observe a strong variation of the photoassociation rate. These results demonstrate the important role of light forces in cw photoassociation at high intensities.

  10. Modulational instability in wind-forced waves

    CERN Document Server

    Brunetti, Maura

    2014-01-01

    We consider the wind-forced nonlinear Schroedinger (NLS) equation obtained in the potential flow framework when the Miles growth rate is of the order of the wave steepness. In this case, the form of the wind-forcing terms gives rise to the enhancement of the modulational instability and to a band of positive gain with infinite width. This regime is characterised by the fact that the ratio between wave momentum and norm is not a constant of motion, in contrast to what happens in the standard case where the Miles growth rate is of the order of the steepness squared.

  11. Predicting hand forces from scalp electroencephalography during isometric force production and object grasping.

    Science.gov (United States)

    Paek, Andrew Y; Gailey, Alycia; Parikh, Pranav; Santello, Marco; Contreras-Vidal, Jose

    2015-01-01

    In this study, we demonstrate the feasibility of predicting hand forces from brain activity recorded with scalp electroencephalography (EEG). Ten able-bodied subjects participated in two tasks: an isometric force production task and a grasp-and-lift task using unconstrained and constrained grasps. We found that EEG electrodes spanning central areas of the scalp were highly correlated to force rate trajectories. Moreover, EEG grand averages in central sites resembled force rate trajectories as opposed to force trajectories. The grasp-and-lift task resulted in higher decoding accuracies than the isometric force production task: across nine subjects, median accuracies for the isometric force production task were r=0.35 whereas median accuracies for unconstrained grasping were r=0.51 and for constrained grasping were r=0.50. Such results could lead to an understanding of the neural representation behind the control of hand forces and could be implemented in the neural control of closed-loop hand-based neuroprostheses.

  12. Bi-Force

    DEFF Research Database (Denmark)

    Sun, Peng; Speicher, Nora K; Röttger, Richard

    2014-01-01

    -clustering', has been successfully utilized to discover local patterns in gene expression data and similar biomedical data types. Here, we contribute a new heuristic: 'Bi-Force'. It is based on the weighted bicluster editing model, to perform biclustering on arbitrary sets of biological entities, given any kind...... of pairwise similarities. We first evaluated the power of Bi-Force to solve dedicated bicluster editing problems by comparing Bi-Force with two existing algorithms in the BiCluE software package. We then followed a biclustering evaluation protocol in a recent review paper from Eren et al. (2013) (A...... datasets from Gene Expression Omnibus were analyzed. All resulting biclusters were subsequently investigated by Gene Ontology enrichment analysis to evaluate their biological relevance. The distinct theoretical foundation of Bi-Force (bicluster editing) is more powerful than strict biclustering. We thus...

  13. Hanscom Air Force Base

    Data.gov (United States)

    Federal Laboratory Consortium — MIT Lincoln Laboratory occupies 75 acres (20 acres of which are MIT property) on the eastern perimeter of Hanscom Air Force Base, which is at the nexus of Lexington,...

  14. Causal reasoning with forces

    Science.gov (United States)

    Wolff, Phillip; Barbey, Aron K.

    2015-01-01

    Causal composition allows people to generate new causal relations by combining existing causal knowledge. We introduce a new computational model of such reasoning, the force theory, which holds that people compose causal relations by simulating the processes that join forces in the world, and compare this theory with the mental model theory (Khemlani et al., 2014) and the causal model theory (Sloman et al., 2009), which explain causal composition on the basis of mental models and structural equations, respectively. In one experiment, the force theory was uniquely able to account for people's ability to compose causal relationships from complex animations of real-world events. In three additional experiments, the force theory did as well as or better than the other two theories in explaining the causal compositions people generated from linguistically presented causal relations. Implications for causal learning and the hierarchical structure of causal knowledge are discussed. PMID:25653611

  15. Romanian Armed Forces Transformation

    Science.gov (United States)

    2007-11-02

    strategic importance is defined by the configuration of the Carpathian Mountains to the north-east, by the lower course and estuary of the Danube river...Companies, 1 Engineer Company, 1 Mountain Company, 1 Military Police Company, 1 Mine-clearing Detachment); Air Forces (4 MIG-21 LANCER, 1 C- 130B...Land Forces - 3 Infantry Companies, 1 Engineer Company, 1 Mountain Company, 1 Paratroops Company, 1 Military Police Company, 1 Demining Detachment

  16. Distributed Surface Force

    Science.gov (United States)

    2014-06-01

    proposed SSC. 1. Definition and Planning The definition and planning phase is appropriate when utilizing any problem- solving algorithm . Before any... MONKEY 149 AGENDA · Background · Scenario · Assumptions · Mission, Commander’s Intent, and Org. Chart · Naval and Air forces . Concept of...forces provide support to Coal ition partners during the execution of Operation Mute Monkey in the South China Sea. · End-state: Deter Chinese

  17. Development of a Standardized Rating Tool for Drug Alerts to Reduce Information Overload.

    Science.gov (United States)

    Pfistermeister, Barbara; Sedlmayr, Brita; Patapovas, Andrius; Suttner, Gerald; Tektas, Ozan; Tarkhov, Aleksey; Kornhuber, Johannes; Fromm, Martin F; Bürkle, Thomas; Prokosch, Hans-Ulrich; Maas, Renke

    2016-12-07

    A well-known problem in current clinical decision support systems (CDSS) is the high number of alerts, which are often medically incorrect or irrelevant. This may lead to the so-called alert fatigue, an overriding of alerts, including those that are clinically relevant, and underuse of CDSS in general. The aim of our study was to develop and to apply a standardized tool that allows its users to evaluate the quality of system-generated drug alerts. The users' ratings can subsequently be used to derive recommendations for developing a filter function to reduce irrelevant alerts. We developed a rating tool for drug alerts and performed a web-based evaluation study that also included a user review of alerts. In this study the following categories were evaluated: "data linked correctly", "medically correct", "action required", "medication change", "critical alert", "information gained" and "show again". For this purpose, 20 anonymized clinical cases were randomly selected and displayed in our customized CDSS research prototype, which used the summary of product characteristics (SPC) for alert generation. All the alerts that were provided were evaluated by 13 physicians. The users' ratings were used to derive a filtering algorithm to reduce overalerting. In total, our CDSS research prototype generated 399 alerts. In 98 % of all alerts, medication data were rated as linked correctly to drug information; in 93 %, the alerts were assessed as "medically correct"; 19.5 % of all alerts were rated as "show again". The interrater-agreement was, on average, 68.4 %. After the application of our filtering algorithm, the rate of alerts that should be shown again decreased to 14.8 %. The new standardized rating tool supports a standardized feedback of user-perceived clinical relevance of CDSS alerts. Overall, the results indicated that physicians may consider the majority of alerts formally correct but clinically irrelevant and override them. Filtering may help to reduce

  18. Another analytic view about quantifying social forces

    CERN Document Server

    Ausloos, Marcel

    2012-01-01

    Montroll had considered a Verhulst evolution approach for introducing a notion he called "social force", to describe a jump in some economic output when a new technology or product outcompetes a previous one. In fact, Montroll's adaptation of Verhulst equation is more like an economic field description than a "social force". The empirical Verhulst logistic function and the Gompertz double exponential law are used here in order to present an alternative view, within a similar mechanistic physics framework. As an example, a "social force" modifying the rate in the number of temples constructed by a religious movement, the Antoinist community, between 1910 and 1940 in Belgium is found and quantified. Practically, two temple inauguration regimes are seen to exist over different time spans, separated by a gap attributed to a specific "constraint", a taxation system, but allowing for a different, smooth, evolution rather than a jump. The impulse force duration is also emphasized as being better taken into account w...

  19. Women in the labor force.

    Science.gov (United States)

    Vatter, R H

    1994-01-01

    Unlike the rate for men, the labor force participation rate for women has increased significantly over the past three decades or so. This trend is expected to continue at least through 2005. Among the reasons for the growing role of women in the labor market are higher levels of educational attainment, improved employment opportunities, changing values in society, and economic pressures and aspirations that require women to assume dual careers as homemakers and family income producers. By the year 2005, it is estimated that women workers will number about 72 million, with more than 63 percent of all women age 16 and over either working or actively looking for work. While traditional occupations such as secretarial and clerical administrative support and professions such as nursing and teaching still predominate, about 4 million women are now in executive, administrative and managerial positions in the private sectors of the economy. As for the types of industry in which women are employed, service industries clearly predominate. Projections suggest that women workers of the future will be older on average, with the fastest growth occurring in the 45-64 age cohort. They will also be a more diverse group as the number of black, Asian and Hispanic women workers grows more rapidly than the number of white non-Hispanic labor force participants.

  20. Analysis and Evaluation of Diabetic Autonomic Neuropathy Analysis of Force and Heart Rate Variability Reduction Rate%心率减速力和心率变异性分析对糖尿病患者自主神经病变的评价功能分析

    Institute of Scientific and Technical Information of China (English)

    邵爱菊; 潘华

    2014-01-01

    目的探讨心率减速力(deceleration capacity ofhear rate,DC)与心率变异性(heart rate variability,HRV)在评价糖尿病患者自主神经功能方面的临床价值。方法对93例糖尿病患者和90名正常人群对照组进行24 h动态心电图检查,导入DMS公司动态分析系统,计算机自动分析DC及HRV时域指标值。结果糖尿病患者的DC值及HRV各时域指标均比对照组降低,差异均有统计学意(P<0.05),表明糖尿病患者自主神经功能受损。结论 DC和HRV检测能定量评估自主神经张力,具有广阔临床应用前景。%Objective To explore the clinical significance ofdeceleration capacity of rate and heart ratevariability (HRV) to evaluating autonomic nervous function in patients with type 2 diabetes.Methods An amount of 93 patients with diabetes and 65 normal control subjects underwent 24 hour dynamic electrocardiogram recordings.DC and time-domain HRV parameters were measured automatical y By the compute.Results DC and time-domain HRV parameters in patients with diabetes were significantly lower than those in control group,This suggests that autonomic nervous function in patients with diabetes is damaged.Conclusion The techniques of DC and HRV can Quantitativily assessment autonomic function, Worthing clinical promotion.

  1. Confusion around the tidal force and the centrifugal force

    CERN Document Server

    Matsuda, Takuya; Boffin, Henri M J

    2015-01-01

    We discuss the tidal force, whose notion is sometimes misunderstood in the public domain literature. We discuss the tidal force exerted by a secondary point mass on an extended primary body such as the Earth. The tidal force arises because the gravitational force exerted on the extended body by the secondary mass is not uniform across the primary. In the derivation of the tidal force, the non-uniformity of the gravity is essential, and inertial forces such as the centrifugal force are not needed. Nevertheless, it is often asserted that the tidal force can be explained by the centrifugal force. If we literally take into account the centrifugal force, it would mislead us. We therefore also discuss the proper treatment of the centrifugal force.

  2. Solving the Sustainable Growth Rate formula conundrum continues steps toward cost savings and care improvements.

    Science.gov (United States)

    Reschovsky, James D; Converse, Larisa; Rich, Eugene C

    2015-04-01

    Congress is again attempting to repeal the Sustainable Growth Rate (SGR) formula. The formula is a failed mechanism intended to constrain Medicare Part B physician spending by adjusting annual physician fee updates. Congress has averted formula-driven physician fee cuts each year beginning in 2003 by overriding the SGR, usually accompanied with last-minute disputes about how these overrides should be paid for. Last year Congress achieved bipartisan and bicameral agreement on legislation to replace the SGR—the SGR Repeal and Medicare Provider Payment Modernization Act of 2014, which we refer to as the "2014 SGR fix"—but was unable to find a way to pay for the legislation under current budget rules. Current congressional deliberations appear focused on how to pay for the fix, with wide consensus that the 2014 legislation should remain the basic model for reform. We describe key features of the 2014 SGR fix, place it in the context of both past and ongoing Medicare health policy, assess its strengths and weaknesses as a mechanism to foster improved care and lower costs in Medicare, and suggest further actions to ensure success in meeting these goals.

  3. USAF Security Forces Training Needs

    National Research Council Canada - National Science Library

    Weeks, Joseph L; Garza, Jorge S; Archuleta, Mark A; McDonald, L. B

    2002-01-01

    .... The Air Force Research Laboratory and McDonald Research Associates have launched a research and development project dedicated to exploring affordable strategies for security forces distributed...

  4. Unified Model of Dynamic Forced Barrier Crossing in Single Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Friddle, R W

    2007-06-21

    Thermally activated barrier crossing in the presence of an increasing load can reveal kinetic rate constants and energy barrier parameters when repeated over a range of loading rates. Here we derive a model of the mean escape force for all relevant loading rates--the complete force spectrum. Two well-known approximations emerge as limiting cases; one of which confirms predictions that single-barrier spectra should converge to a phenomenological description in the slow loading limit.

  5. Ratings Revisited

    DEFF Research Database (Denmark)

    Lai, Signe Sophus

    2015-01-01

    tværs af medier og platforme, forskudt i tid og on-demand. This article focuses on audience ratings, which have functioned as the central ‘currency’ informing the media trade. It discusses changes to the production and accuracy of audience ratings at a time when established standards are being...... consumption. It argues that current tracking systems cannot capture increasingly cross-media, time-shifted, mobile, and on-demand audience behavior....

  6. Contact Force Compensated Thermal Stimulators for Holistic Haptic Interfaces.

    Science.gov (United States)

    Sim, Jai Kyoung; Cho, Young-Ho

    2016-05-01

    We present a contact force compensated thermal stimulator that can provide a consistent tempera- ture sensation on the human skin independent of the contact force between the thermal stimulator and the skin. Previous passive thermal stimulators were not capable of providing a consistent tem- perature on the human skin even when using identical heat source voltage due to an inconsistency of the heat conduction, which changes due to the force-dependent thermal contact resistance. We propose a force-based feedback method that monitors the contact force and controls the heat source voltage according to this contact force, thus providing consistent temperature on the skin. We composed a heat circuit model equivalent to the skin heat-transfer rate as it is changed by the contact forces; we obtained the optimal voltage condition for the constant skin heat-transfer rate independent of the contact force using a numerical estimation simulation tool. Then, in the experiment, we heated real human skin at the obtained heat source voltage condition, and investigated the skin heat transfer-rate by measuring the skin temperature at various times at different levels of contact force. In the numerical estimation results, the skin heat-transfer rate for the contact forces showed a linear profile in the contact force range of 1-3 N; from this profile we obtained the voltage equation for heat source control. In the experimental study, we adjusted the heat source voltage according to the contact force based on the obtained equation. As a result, without the heat source voltage control for the contact forces, the coefficients of variation (CV) of the skin heat-transfer rate in the contact force range of 1-3 N was found to be 11.9%. On the other hand, with the heat source voltage control for the contact forces, the CV of the skin heat-transfer rate in the contact force range of 1-3 N was found to be barely 2.0%, which indicate an 83.2% improvement in consistency compared to the skin heat

  7. Determinants of the Declining Share of Agricultural Labour Force to Total Labour Force in Pakistan

    OpenAIRE

    KHALID HAMEED SHEIKH; ZAFAR IQBAL

    1988-01-01

    The agricultural labour force in Pakistan has been increasing rapidly due to population growth as well as a declining mortality rate. However, the share of the agricultural labour force to total labour force has been decreasing. The objective of this paper is to search for the factors responsible for this decline. The period covered is from 1959-60 to 1986-87. The development process is characterised as one which brings about a fundamental change in the structure of an economy. In this proces...

  8. Forces in strategy formation

    DEFF Research Database (Denmark)

    Steensen, Elmer Fly

    2008-01-01

    This chapter proposes that organizational strategy formation should be characterized theoretically as a process that is subject to several interacting forces, rather than represented by separate discrete decisionmodels or theoretic perspectives, as is commonly done in the strategic management...... literature. Based on an extensive review of relevant theory and empirical work in strategic decision-making, organizational change theory, cognitive and social psychology, and strategy processes, seven kinds of ''forces'' - rational, imposed, teleological, learning, political, heuristic, and social...... - are identified as interacting in and having significant influence on the strategy formation process. It is further argued that by applying a holistic ''forces-view'' of the significant and interacting influences on strategy formation, we can better understand the dynamics and challenges in managing the process...

  9. Rectified Forces in Rubidium

    Science.gov (United States)

    Grove, Timothy Todd

    The forces exerted on a three-level atom by a bichromatic standing-wave field are investigated. A theoretical analysis shows that the standing-wave dipole force can be rectified, i.e., maintain its sign over many optical wavelengths. Three systems in particular are studied: the lambda, the vee, and the cascade. Experimental results for the rubidium 5S --> 5P --> 5D cascade system are used to confirm the theory. The nearly coincident transition wavelengths for this system (780.0 nm and 776.0 nm) provide potential wells repeating at the beat wavelength (71 μm) which can accumulate laser cooled atoms. This force may have future applications in forming deep neutral atom traps as well as in the creation of new elements for atom optics. Two-color, two-photon spectroscopy of the 5D_{5/2}cascade system (5S --> 5P --> 5D) was also performed.

  10. Force-Free Foliations

    CERN Document Server

    Compère, Geoffrey; Lupsasca, Alexandru

    2016-01-01

    Electromagnetic field configurations with vanishing Lorentz force density are known as force-free and appear in terrestrial, space, and astrophysical plasmas. We explore a general method for finding such configurations based on formulating equations for the field lines rather than the field itself. The basic object becomes a foliation of spacetime or, in the stationary axisymmetric case, of the half-plane. We use this approach to find some new stationary and axisymmetric solutions, one of which could represent a rotating plasma vortex near a magnetic null point.

  11. Electrochemical force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kalinin, Sergei V.; Jesse, Stephen; Collins, Liam F.; Rodriguez, Brian J.

    2017-01-10

    A system and method for electrochemical force microscopy are provided. The system and method are based on a multidimensional detection scheme that is sensitive to forces experienced by a biased electrode in a solution. The multidimensional approach allows separation of fast processes, such as double layer charging, and charge relaxation, and slow processes, such as diffusion and faradaic reactions, as well as capturing the bias dependence of the response. The time-resolved and bias measurements can also allow probing both linear (small bias range) and non-linear (large bias range) electrochemical regimes and potentially the de-convolution of charge dynamics and diffusion processes from steric effects and electrochemical reactivity.

  12. The Force-Velocity Relation for Growing Biopolymers

    CERN Document Server

    Carlsson, A E

    2000-01-01

    The process of force generation by the growth of biopolymers is simulated via a Langevin-dynamics approach. The interaction forces are taken to have simple forms that favor the growth of straight fibers from solution. The force-velocity relation is obtained from the simulations for two versions of the monomer-monomer force field. It is found that the growth rate drops off more rapidly with applied force than expected from the simplest theories based on thermal motion of the obstacle. The discrepancies amount to a factor of three or more when the applied force exceeds 2.5kT/a, where a is the step size for the polymer growth. These results are explained on the basis of restricted diffusion of monomers near the fiber tip. It is also found that the mobility of the obstacle has little effect on the growth rate, over a broad range.

  13. Total aerosol effect: forcing or radiative flux perturbation?

    Energy Technology Data Exchange (ETDEWEB)

    Lohmann, Ulrike; Storelvmo, Trude; Jones, Andy; Rotstayn, Leon; Menon, Surabi; Quaas, Johannes; Ekman, Annica; Koch, Dorothy; Ruedy, Reto

    2009-09-25

    Uncertainties in aerosol forcings, especially those associated with clouds, contribute to a large extent to uncertainties in the total anthropogenic forcing. The interaction of aerosols with clouds and radiation introduces feedbacks which can affect the rate of rain formation. Traditionally these feedbacks were not included in estimates of total aerosol forcing. Here we argue that they should be included because these feedbacks act quickly compared with the time scale of global warming. We show that for different forcing agents (aerosols and greenhouse gases) the radiative forcings as traditionally defined agree rather well with estimates from a method, here referred to as radiative flux perturbations (RFP), that takes these fast feedbacks and interactions into account. Thus we propose replacing the direct and indirect aerosol forcing in the IPCC forcing chart with RFP estimates. This implies that it is better to evaluate the total anthropogenic aerosol effect as a whole.

  14. Modeling and experimentation of bone drilling forces.

    Science.gov (United States)

    Lee, JuEun; Gozen, B Arda; Ozdoganlar, O Burak

    2012-04-05

    Prediction and control of bone drilling forces are critical to the success of many orthopaedic operations. Uncontrolled and large forces can cause drill-bit breakage, drill breakthrough, excessive heat generation, and mechanical damage to the bone. This paper presents a mechanistic model for prediction of thrust forces and torques experienced during bone drilling. The model incorporates the radially varying drill-bit geometry and cutting conditions analytically, while capturing the material and friction properties empirically through a specific energy formulation. The forces from the chisel edge are modeled by considering the indentation process that occurs in the vicinity of the drill-bit axis. A procedure is outlined to calibrate the specific energies, where only a small number of calibration experiments are required for a wide range of drilling conditions and drill-bit geometry. The calibration parameters for the cortical portions of bovine tibia are identified through drilling tests. Subsequently, a series of validation tests are conducted under different feed rates and spindle speeds. The thrust forces and torques were observed to vary considerably between bones from different animals. The forces from the model were seen to match well with those from the experimentation within the inherent variations from the bone characteristics. The model can be used to select favorable drilling conditions, to assist in robotic surgeries, and to design optimal orthopaedic drill bits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Multiple barriers in forced rupture of protein complexes

    CERN Document Server

    Hyeon, Changbong

    2012-01-01

    Curvatures in the most probable rupture force ($f^*$) versus log-loading rate ($\\log{r_f}$) observed in dynamic force spectroscopy (DFS) on biomolecular complexes are interpreted using a one-dimensional free energy profile with multiple barriers or a single barrier with force-dependent transition state. Here, we provide a criterion to select one scenario over another. If the rupture dynamics occurs by crossing a single barrier in a physical free energy profile describing unbinding, the exponent $\

  16. ANALYSIS ON THE SPINNING FORCES IN FLEXIBLE SPINNING OF CONES

    Institute of Scientific and Technical Information of China (English)

    Xia Qinxiang; Susumu Shima

    2003-01-01

    Flexible spinning is a new type of spinning process where spin-forming is performed without using a mandrel. Combining shearing and rolling processes, the calculation formulas of thespinning forces in flexible spinning of cones is presented. The effects of the main processing parameters, such as gripping force G applied to the blank by the inner roller, the feed rate of rollersfand the roundness radius of outer roller ro, on the spinning forces are analyzed experimentally and theoretically.

  17. Intramuscular fiber conduction velocity, isometric force and explosive performance

    OpenAIRE

    Methenitis Spyridon; Terzis Gerasimos; Zaras Nikolaos; Stasinaki Angeliki-Nikoletta; Karandreas Nikolaos

    2016-01-01

    Conduction of electrical signals along the surface of muscle fibers is acknowledged as an essential neuromuscular component which is linked with muscle force production. However, it remains unclear whether muscle fiber conduction velocity (MFCV) is also linked with explosive performance. The aim of the present study was to investigate the relationship between vastus lateralis MFCV and countermovement jumping performance, the rate of force development and maximum isometric force. Fifteen moder...

  18. Intramuscular fiber conduction velocity, isometric force and explosive performance

    OpenAIRE

    Methenitis, Spyridon; Terzis, Gerasimos; Zaras, Nikolaos; Stasinaki, Angeliki-Nikoletta; Karandreas, Nikolaos

    2016-01-01

    Abstract Conduction of electrical signals along the surface of muscle fibers is acknowledged as an essential neuromuscular component which is linked with muscle force production. However, it remains unclear whether muscle fiber conduction velocity (MFCV) is also linked with explosive performance. The aim of the present study was to investigate the relationship between vastus lateralis MFCV and countermovement jumping performance, the rate of force development and maximum isometric force. Fift...

  19. International Quick Response Forces

    Science.gov (United States)

    1994-06-06

    humaijitarian relief, maintenance of a cease-fire, and promocion of national reconciliation - and became a manhunt for Somali warlord Mohamed Farah...maritime components would accompany this 6 5This scheme is adopted from USPACOM’s and USACOM’s Joint Task Force and JuiiL AdapUiv= Fuce Packages

  20. due to Capillary Forces

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2009-01-01

    Full Text Available We present modeling and analysis for the static behavior and collapse instabilities of doubly-clamped and cantilever microbeams subjected to capillary forces. These forces can be as a result of a volume of liquid trapped underneath the microbeam during the rinsing and drying process in fabrication. The model considers the microbeam as a continuous medium, the capillary force as a nonlinear function of displacement, and accounts for the mid-plane stretching and geometric nonlinearities. The capillary force is assumed to be distributed over a specific length underneath the microbeam. The Galerkin procedure is used to derive a reduced-order model consisting of a set of nonlinear algebraic and differential equations that describe the microbeams static and dynamic behaviors. We study the collapse instability, which brings the microbeam from its unstuck configuration to touch the substrate and gets stuck in the so-called pinned configuration. We calculate the pull-in length that distinguishes the free from the pinned configurations as a function of the beam thickness and gap width for both microbeams. Comparisons are made with analytical results reported in the literature based on the Ritz method for linear and nonlinear beam models. The instability problem, which brings the microbeam from a pinned to adhered configuration is also investigated. For this case, we use a shooting technique to solve the boundary-value problem governing the deflection of the microbeams. The critical microbeam length for this second instability is also calculated.

  1. Allegiance: Egypt Security Forces

    Science.gov (United States)

    2013-12-01

    square, the very definition of political jiu-jitsu.124 The CSF commanders continued to press protestors, often using lethal force.125 The battle on...incident France 2 had a crew of four arrested and held for 10 hours on August while Jared Malsin, who works for Time Magazine and freelance photographer

  2. Use of Security Forces

    OpenAIRE

    International Finance Corporation

    2017-01-01

    This Good Practice Handbook on the Use of Security Forces: Assessing and Managing Risks and Impacts has been developed for IFC clients and other private sector companies and their consultants. The handbook provides practical, project-level guidance for companies to better understand and implement the requirements outlined in Performance Standard 4. Chapters focus on risk assessment, managi...

  3. 10K Force Analysis

    Science.gov (United States)

    1993-06-01

    hellfire missiles for the longbow helicopters, TACMS Block II MLRS, and cluster m bombs for the fixed wing assets. c. What capabilities will the force need...Essential Elements of Analysis (EEA) 3 5. NEASURES OF PERORNANCE . ...... 3 .6. STUDYA LTZRNATIVE£ ......... . 4 7. METODOLOGY ... ...... . . . . 4 8

  4. Muscle contraction and force

    DEFF Research Database (Denmark)

    Brüggemann, Dagmar Adeline; Risbo, Jens; Pierzynowski, Stefan G.

    2008-01-01

    Muscle contraction studies often focus solely on myofibres and the proteins known to be involved in the processes of sarcomere shortening and cross-bridge cycling, but skeletal muscle also comprises a very elaborate ancillary network of capillaries, which not only play a vital role in terms...... contributor to force transfer within muscular tissue....

  5. Unusual ISS Rate Signature

    Science.gov (United States)

    Laible, Michael R.

    2011-01-01

    On November 23, 2011 International Space Station Guidance, Navigation, and Control reported unusual pitch rate disturbance. These disturbances were an order of magnitude greater than nominal rates. The Loads and Dynamics team was asked to review and analyze current accelerometer data to investigate this disturbance. This paper will cover the investigation process under taken by the Loads and Dynamics group. It will detail the accelerometers used and analysis performed. The analysis included performing Frequency Fourier Transform of the data to identify the mode of interest. This frequency data is then reviewed with modal analysis of the ISS system model. Once this analysis is complete and the disturbance quantified, a forcing function was produced to replicate the disturbance. This allows the Loads and Dynamics team to report the load limit values for the 100's of interfaces on the ISS.

  6. Constant force extensional rheometry of polymer solutions

    DEFF Research Database (Denmark)

    Szabo, Peter; McKinley, Gareth H.; Clasen, Christian

    2012-01-01

    We revisit the rapid stretching of a liquid filament under the action of a constant imposed tensile force, a problem which was first considered by Matta and Tytus [J. Non-Newton. Fluid Mech. 35 (1990) 215–229]. A liquid bridge formed from a viscous Newtonian fluid or from a dilute polymer solution...... filament can be probed. In particular, we show that with this constant force pull (CFP) technique it is possible to readily impose very large material strains and strain rates so that the maximum extensibility of the polymer molecules may be quantified. This unique characteristic of the experiment...

  7. The van der Waals force and gravitational force in matter

    CERN Document Server

    Zhang, Lei

    2013-01-01

    It was thought that the van der Waals force and gravitational force were distinct. Now a model is used to describe the attraction between macroscopic objects according to van der Waals interaction. The force between two objects with thermal equilibrium deviates from the law of universal gravitation slightly, and the gravity on the earth is explained approximately. We argue that the gravitational force is the van der Waals force actually. In other words, the gravitational force and mass are related to the quantum fluctuations of electron clouds in atoms, and these parameters are dictated by dielectric susceptibility.

  8. Influence of maglev force relaxation on the forces of bulk HTSC subjected to different lateral displacements above the NdFeB guideway

    Science.gov (United States)

    Qin, Yujie; Hou, Xiaojing

    2011-02-01

    This paper studied the influence of maglev force relaxation on the force (both levitation and guidance forces) of bulk high-temperature superconductor (HTSC) subjected to different lateral displacements above a NdFeB guideway. Firstly, the maglev forces relaxation property of bulk HTSC above the permanent-magnet guideway (PMG) was studied experimentally, then the levitation and guidance forces were measured by SCML-2 measurement system synchronously at different lateral displacements, some times later(after relaxation), the forces were measured again as the same way. Compared to the two measured results, it was found that the change of the levitation force was larger compared to the case without relaxation, while the change of the guidance force was smaller. In addition, the rate of change of levitation force and guidance force was different for different maximum lateral displacements. This work provided a scientific analysis for the practical application of the bulk HTS.

  9. Force Modulator System

    Energy Technology Data Exchange (ETDEWEB)

    Redmond Clark

    2009-04-30

    Many metal parts manufacturers use large metal presses to shape sheet metal into finished products like car body parts, jet wing and fuselage surfaces, etc. These metal presses take sheet metal and - with enormous force - reshape the metal into a fully formed part in a manner of seconds. Although highly efficient, the forces involved in forming metal parts also damage the press itself, limit the metals used in part production, slow press operations and, when not properly controlled, cause the manufacture of large volumes of defective metal parts. To date, the metal-forming industry has not been able to develop a metal-holding technology that allows full control of press forces during the part forming process. This is of particular importance in the automotive lightweighting efforts under way in the US automotive manufacturing marketplace. Metalforming Controls Technology Inc. (MC2) has developed a patented press control system called the Force Modulator that has the ability to control these press forces, allowing a breakthrough in stamping process control. The technology includes a series of hydraulic cylinders that provide controlled tonnage at all points in the forming process. At the same time, the unique cylinder design allows for the generation of very high levels of clamping forces (very high tonnages) in very small spaces; a requirement for forming medium and large panels out of HSS and AHSS. Successful production application of these systems testing at multiple stamping operations - including Ford and Chrysler - has validated the capabilities and economic benefits of the system. Although this technology has been adopted in a number of stamping operations, one of the primary barriers to faster adoption and application of this technology in HSS projects is system cost. The cost issue has surfaced because the systems currently in use are built for each individual die as a custom application, thus driving higher tooling costs. This project proposed to better

  10. Force Feedback Joystick

    Science.gov (United States)

    1997-01-01

    I-FORCE, a computer peripheral from Immersion Corporation, was derived from virtual environment and human factors research at the Advanced Displays and Spatial Perception Laboratory at Ames Research Center in collaboration with Stanford University Center for Design Research. Entrepreneur Louis Rosenberg, a former Stanford researcher, now president of Immersion, collaborated with Dr. Bernard Adelstein at Ames on studies of perception in virtual reality. The result was an inexpensive way to incorporate motors and a sophisticated microprocessor into joysticks and other game controllers. These devices can emulate the feel of a car on the skid, a crashing plane, the bounce of a ball, compressed springs, or other physical phenomenon. The first products incorporating I-FORCE technology include CH- Products' line of FlightStick and CombatStick controllers.

  11. ASEAN Combined Forces Command

    Science.gov (United States)

    1992-04-03

    nation building and the restoration of the democratic system through the general election which took place in March 1992. Malaysia. In West Malaysia’s...This problem is a result of different concepts for building the nation’s democratic system . I believe they will eventually solve it. Sinaapore...people, not only the armed forces. This organization is once more threatening to the democratic system of the country. By the next election, it is

  12. Ultrasonic Force Microscopies

    Science.gov (United States)

    Kolosov, Oleg; Briggs, Andrew

    Ultrasonic Force Microscopy, or UFM, allows combination of two apparently mutually exclusive requirements for the nanomechanical probe—high stiffness for the efficient indentation and high mechanical compliance that brings force sensitivity. Somewhat inventively, UFM allows to combine these two virtues in the same cantilever by using indention of the sample at high frequency, when cantilever is very rigid, but detecting the result of this indention at much lower frequency. That is made possible due to the extreme nonlinearity of the nanoscale tip-surface junction force-distance dependence, that acts as "mechanical diode" detecting ultrasound in AFM. After introducing UFM principles, we discuss features of experimental UFM implementation, and the theory of contrast in this mode, progressing to quantitative measurements of contact stiffness. A variety of UFM applications ranging from semiconductor quantum nanostructures, graphene, very large scale integrated circuits, and reinforced ceramics to polymer composites and biological materials is presented via comprehensive imaging gallery accompanied by the guidance for the optimal UFM measurements of these materials. We also address effects of adhesion and topography on the elasticity imaging and the approaches for reducing artifacts connected with these effects. This is complemented by another extremely useful feature of UFM—ultrasound induced superlubricity that allows damage free imaging of materials ranging from stiff solid state devices and graphene to biological materials. Finally, we proceed to the exploration of time-resolved nanoscale phenomena using nonlinear mixing of multiple vibration frequencies in ultrasonic AFM—Heterodyne Force Microscopy, or HFM, that also include mixing of ultrasonic vibration with other periodic physical excitations, eg. electrical, photothermal, etc. Significant section of the chapter analyzes the ability of UFM and HFM to detect subsurface mechanical inhomogeneities, as well as

  13. Joint Forces Capabilities

    Science.gov (United States)

    2007-11-02

    for countering the proliferation of weapons of mass destruction (WMD) in space. The Space Operations Center ( SPOC ), USSPACECOM is the single point...of contact for assessing space capabilities. Combatant commanders, subordinate JFCs, and Services can access this information from the SPOC via the...special operations forces SPOC Space Operations Center SSBN fleet ballistic missile submarine SST space support team UJTL Universal Joint Task List UN

  14. Concepts of force

    CERN Document Server

    Jammer, Max

    2011-01-01

    Both historical treatment and critical analysis, this work by a noted physicist takes a fascinating look at a fundamental of physics, tracing its development from ancient to modern times. Kepler's initiation of scientific conceptualization, Newton's definition, post-Newtonian reinterpretation - contrasting concepts of Leibniz, Boscovich, Kant with those of Mach, Kirchhoff, Hertz. In-depth analysis of contemporary trend toward eliminating force from conceptual scheme of physics. ""An excellent presentation."" - Science. 1962 edition.

  15. Force Employment Study (FES)

    Science.gov (United States)

    1991-02-01

    E-2 E-6 Snow Removal, Providence .. ....... ...........E-2 E-7 Tornado, Hopkinville, KY .. ....... ...........E-2 E-8 Volcano , Mt...Del Valle. The National Assembly met late on 25 Feb and replaced Del Valle with a Noriega-supported president, Solis- Palma . On 16 March, there was a... volcano eruption. Force composition: See Figure 3-18 Component: Active Army Man-day expenditure: 426 soldiers; 8,086 man-days Mode of deployment

  16. Is Gravity Entropic Force?

    Directory of Open Access Journals (Sweden)

    Rongjia Yang

    2014-08-01

    Full Text Available If we assume that the source of thermodynamic system, ρ and p, are also the source of gravity, then either thermal quantities, such as entropy, temperature, and chemical potential, can induce gravitational effects, or gravity can induce thermal effects. We find that gravity can be seen as entropic force only for systems with constant temperature and zero chemical potential. The case for Newtonian approximation is discussed.

  17. Air Force Power Requirements

    Science.gov (United States)

    2006-01-24

    2 Outline • Our Recent Heritage – MEA • Our Plan – HiPAC • HiPAC Technologies • Summary Powering the United States Air Force NASA AI R FO RC E NA VY...Aircraft i l i Munitions / UAV i i / Micro-Mini Platforms i i i l HiPAC Technical Program Areas • High Temperature Power System Components • High

  18. Gap Task Force

    CERN Multimedia

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  19. ``Force,'' ontology, and language

    Science.gov (United States)

    Brookes, David T.; Etkina, Eugenia

    2009-06-01

    We introduce a linguistic framework through which one can interpret systematically students’ understanding of and reasoning about force and motion. Some researchers have suggested that students have robust misconceptions or alternative frameworks grounded in everyday experience. Others have pointed out the inconsistency of students’ responses and presented a phenomenological explanation for what is observed, namely, knowledge in pieces. We wish to present a view that builds on and unifies aspects of this prior research. Our argument is that many students’ difficulties with force and motion are primarily due to a combination of linguistic and ontological difficulties. It is possible that students are primarily engaged in trying to define and categorize the meaning of the term “force” as spoken about by physicists. We found that this process of negotiation of meaning is remarkably similar to that engaged in by physicists in history. In this paper we will describe a study of the historical record that reveals an analogous process of meaning negotiation, spanning multiple centuries. Using methods from cognitive linguistics and systemic functional grammar, we will present an analysis of the force and motion literature, focusing on prior studies with interview data. We will then discuss the implications of our findings for physics instruction.

  20. Adding Value to Force Diagrams: Representing Relative Force Magnitudes

    Science.gov (United States)

    Wendel, Paul

    2011-05-01

    Nearly all physics instructors recognize the instructional value of force diagrams, and this journal has published several collections of exercises to improve student skill in this area.1-4 Yet some instructors worry that too few students perceive the conceptual and problem-solving utility of force diagrams,4-6 and over recent years a rich variety of approaches has been proposed to add value to force diagrams. Suggestions include strategies for identifying candidate forces,6,7 emphasizing the distinction between "contact" and "noncontact" forces,5,8 and the use of computer-based tutorials.9,10 Instructors have suggested a variety of conventions for constructing force diagrams, including approaches to arrow placement and orientation2,11-13 and proposed notations for locating forces or marking action-reaction force pairs.8,11,14,15

  1. Force transmission in epithelial tissues.

    Science.gov (United States)

    Vasquez, Claudia G; Martin, Adam C

    2016-03-01

    In epithelial tissues, cells constantly generate and transmit forces between each other. Forces generated by the actomyosin cytoskeleton regulate tissue shape and structure and also provide signals that influence cells' decisions to divide, die, or differentiate. Forces are transmitted across epithelia because cells are mechanically linked through junctional complexes, and forces can propagate through the cell cytoplasm. Here, we review some of the molecular mechanisms responsible for force generation, with a specific focus on the actomyosin cortex and adherens junctions. We then discuss evidence for how these mechanisms promote cell shape changes and force transmission in tissues.

  2. Frequency Population Growth Rate

    Directory of Open Access Journals (Sweden)

    Nouralah Salehi Asfiji

    2012-10-01

    Full Text Available The Solow growth model assumes that labor force grows exponentially. That is not a realistic assumption. In generalized logistic equations that describes more accurately population growth. Economic growth is not a smooth process. Real GDP has fluctuations in the growth rate. We call these fluctuations business cycles. Business cycle theory came about from the failures of classical economics in being able to illuminate on the causes of the Great Depression. The logistic growth model to explain changes in population growth rates are not. In this paper a new analysis of the population growth rate in the frequency space is described with mathematical logic and economic reasoning, so that, firstly, to a higher level of capital per capita, or at least equal to the Solow growth model reaches Second, the limits of saturation (Carrying-Capacity is not, and ultimately, population growth rates have an impact on long-term per capita amounts. The initial classic assumption is changed in this article based on the available frequencies in the population growth equation.

  3. Force-distance curves by atomic force microscopy

    OpenAIRE

    Cappella, Bruno; Dietler, Giovanni

    1999-01-01

    Atomic force microscopy (AFM) force-distance curves have become a fundamental tool in several fields of research, such as surface science, materials engineering, biochemistry and biology. Furthermore, they have great importance for the study of surface interactions from a theoretical point of view. Force-distance curves have been employed for the study of numerous materials properties and for the characterization of all the known kinds of surface forces. Since 1989, several techniques of acqu...

  4. Proximal arm kinematics affect grip force-load force coordination

    OpenAIRE

    Vermillion, Billy C.; Lum, Peter S; Lee, Sang Wook

    2015-01-01

    During object manipulation, grip force is coordinated with load force, which is primarily determined by object kinematics. Proximal arm kinematics may affect grip force control, as proximal segment motion could affect control of distal hand muscles via biomechanical and/or neural pathways. The aim of this study was to investigate the impact of proximal kinematics on grip force modulation during object manipulation. Fifteen subjects performed three vertical lifting tasks that involved distinct...

  5. The labor force of the future.

    Science.gov (United States)

    Norwood, J L

    1987-07-01

    In the decades ahead, the US labor force will reflect changes in the industrial structure, with declines in some manufacturing industries and expansion in service industries. The services sector is so diverse that the jobs within it cannot be categorized as either high wage or low wage. The service-producing sector employs 85% of professional specialty workers in the US. In general, information on compensation trends indicates that greater increases in compensation have occurred for workers in service-producing as opposed to goods-producing industries. The increase in service sector jobs has created opportunities for women to enter the labor force and, at present, 5 out of 6 women work in this sector compared to fewer than 2 out of 3 men. Productivity growth rates in the service-producing industries vary substantially and are strongly affected by the business cycle. Central to employment opportunities in the years ahead will be the effect of new technology. To date, the aggregate effect of new technology has been increased employment and higher living standards. Although retraining programs should be in place, the scenario of a huge technology-created labor surplus seems unlikely. In fact, a more likely problem is a shortage of labor resulting from earlier labor force withdrawal and demographic aging of the population. Those in the 25-54-year age group will represent a larger share of the labor force in the years ahead. In addition, blacks are expected to account for 20% of the labor force growth in the next decade. Finally, given increasing labor force participation rates among mothers, employers may have to provide more flexible work schedules, assistance with day care, and more attractive benefits packages.

  6. Predictability of Forced Lorenz Systems

    Science.gov (United States)

    Li, Baosheng; Ding, Ruiqiang; Li, Jianping; Zhong, Quanjia

    2017-04-01

    Based on the nonlinear local Lyapunov exponent (NLLE) approach, the influences of external forcing on the predictability are studied in the Lorenz systems with constant and quasi-periodic forces in this paper. The results indicate that for the Lorenz systems with constant and quasi-periodic forces, their predictability limits increase with the forcing strength. With the same magnitude and different directions, the constant or quasi-periodic forcing shows different effects on the predictability limit in the Lorenz system, and these effects become significant with the increase of the forcing strength. Generally speaking, the positive forcing leads to a higher predictability limit than the negative forcing. Therefore, when we think about the effects of positive and negative elements and phases in the atmosphere and ocean research, the predictability problems driven by different phases should be considered separately. In addition, the influences of constant and quasi-periodic forces on the predictability are different in the Lorenz system. The effect of the constant forcing on the predictability is mainly reflected in the linear phase of error growth, while the nonlinear phase should also be considered for the situation of the quasi-periodic forcing. The predictability limit of the system under constant forcing is longer than the system under quasi-periodic forcing. These results based on simple chaotic model could provide insight into the studies of the actual atmosphere predictability.

  7. Sample dependence of the Casimir forces

    CERN Document Server

    Pirozhenko, I; Svetovoy, V B

    2006-01-01

    We have analyzed available optical data for Au in the mid-infrared range which is important for a precise prediction of the Casimir force. Significant variation of the data demonstrates genuine sample dependence of the dielectric function. We demonstrate that the Casimir force is largely determined by the material properties in the low frequency domain and argue that therefore the precise values of the Drude parameters are crucial for an accurate evaluation of the force. These parameters can be estimated by two different methods, either by fitting real and imaginary parts of the dielectric function at low frequencies, or via a Kramers-Kronig analysis based on the imaginary part of the dielectric function in the extended frequency range. Both methods lead to very similar results. We show that the variation of the Casimir force calculated with the use of different optical data can be as large as 5% and at any rate cannot be ignored. To have a reliable prediction of the force with a precision of 1%, one has to m...

  8. Kinesio Taping effects on knee extension force among soccer players

    Directory of Open Access Journals (Sweden)

    Maysa V. G. B. Serra

    2015-04-01

    Full Text Available Background : Kinesio Taping (KT is widely used, however the effects of KT on muscle activation and force are contradictory. Objective : To evaluate the effects of KT on knee extension force in soccer players. Method: This is a clinical trial study design. Thirty-four subjects performed two maximal isometric voluntary contractions of the lower limbs pre, immediately post, and 24 hours after tape application on the lower limbs. Both lower limbs were taped, using K-Tape and 3M Micropore tape randomly on the right and left thighs of the participants. Isometric knee extension force was measured for dominant side using a strain gauge. The following variables were assessed: peak force, time to peak force, rate of force development until peak force, time to peak rate of force development, and 200 ms pulse. Results : There were no statistically significant differences in the variables assessed between KT and Micropore conditions (F=0.645, p=0.666 or among testing sessions (pre, post, and 24h after (F=0.528, p=0.868, and there was no statistical significance (F=0.271, p=0.986 for interaction between tape conditions and testing session. Conclusion: KT did not affect the force-related measures assessed immediately and 24 hours after the KT application compared with Micropore application, during maximal isometric voluntary knee extension.

  9. Force Dynamics of Verb Complementation

    Directory of Open Access Journals (Sweden)

    Jacek Woźny

    2015-12-01

    Full Text Available Force Dynamics of Verb Complementation The concepts of motion and force are both extensively discussed in cognitive linguistics literature. But they are discussed separately. The first usually in the context of ‘motion situations’ (Talmy, Slobin, Zlatev, the other as part of the Force Dynamics framework, which was developed by Talmy. The aim of this paper is twofold: first, to argue that the concepts of force and motion should not be isolated but considered as two inseparable parts of force-motion events. The second goal is to prove that the modified Force Dynamics (force-motion framework can be used for precise characterization of the verb complementation patterns. To this end, a random sample of 50 sentences containing the verb ‘went’ is analyzed, demonstrating the differences between the categories of intensive and intransitive complementation with respect to the linguistically coded parameters of force and motion.

  10. Modernization of African Armed Forces

    DEFF Research Database (Denmark)

    Mandrup, Thomas

    2015-01-01

    Concept paper framing the debate at the Dakar Forum Workshop on Modernization of Armed forces in Africa.......Concept paper framing the debate at the Dakar Forum Workshop on Modernization of Armed forces in Africa....

  11. Levitation force relaxation under reloading in a HTS Maglev system

    Science.gov (United States)

    He, Qingyong; Wang, Jiasu; Wang, Suyu; Wang, Jiansi; Dong, Hao; Wang, Yuxin; Shao, Senhao

    2009-02-01

    The loading capacity of the high-temperature superconducting (HTS) Maglev vehicle is an important parameter in the practical application. It is closely related to the levitation force of the HTS bulk. Many papers reported that the levitation force showed the relaxation characteristic. Because different loads cause different levitation gaps and different applied magnetic fields, the levitation force relaxations under the different loads are not the same. In terms of cylindrical YBCO bulk levitated over the permanent magnetic guideway, the relationship between the levitation force relaxation and the reloading is investigated experimentally in this paper. The decrement, the decrement rate and the relaxation rate of the levitation force are calculated, respectively. This work might be helpful for studying the loading capacity of the HTS Maglev vehicle.

  12. Genetic Evolutionary Approach for Cutting Forces Prediction in Hard Milling

    Science.gov (United States)

    Taylan, Fatih; Kayacan, Cengiz

    2011-11-01

    Hard milling is a very common used machining procedure in the last years. Therefore the prediction of cutting forces is important. The paper deals with this prediction using genetic evolutionary programming (GEP) approach to set mathematical expression for out cutting forces. In this study, face milling was performed using DIN1.2842 (90MnCrV8) cold work tool steel, with a hardness of 61 HRC. Experimental parameters were selected using stability measurements and simulations. In the hard milling experiments, cutting force data in a total of three axes were collected. Feed direction (Fx) and tangential direction (Fy) cutting forces generated using genetic evolutionary programming were modelled. Cutting speed and feed rate values were treated as inputs in the models, and average cutting force values as output. Mathematical expressions were created to predict average Fxand Fy forces that can be generated in hard material milling.

  13. Calorimetry Task Force Report

    CERN Document Server

    Abdullin, Salavat; Banerjee, Sunanda; Beauceron, Stephanie; Beaudette, Florian; Bhatti, Anwar; Chlebana, Frank; Cossutti, Fabio; Hirschauer, James; Ivanchenko, V; Jang, Dong Wook; Jun, Soon Yung; Kunori, Shuichi; Kroeger, Rob; Liu, Yanwen; Moeller, Anthony; Paulini, Manfred; Piperov, Stefan; Rahmat, Rahmat; Rovelli, Chiara; Safronov, Grigory; Sharma, Seema; Spiropulu, Maria; Yetkin, Taylan

    2010-01-01

    In this note we summarize the progress made by the calorimeter simulation task force (CaloTF) over the past year. The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and test beam data recorded during 2004 and 2006. The simulation has been significantly improved by using a newer version of Geant4 and an improved physics list for the full CMS detector simulation. Simulation times have been reduced by introducing flexible parameterizations to describe showering in the calorimeter (using a Gflash-like approach) which have been tuned to the test beam data.

  14. Force sensor free teleoperated robotic surgery : Interaction force estimation for realistic force feedback without force sensors

    OpenAIRE

    Nærum, Edvard

    2012-01-01

    List of papers. The papers are removed from the thesis due to copyright restrictions. Paper I E. Naerum, J. Cornellà and O.J. Elle. Wavelet networks for estimation of coupled friction in robotic manipulators Proc. IEEE Conference on Robotics and Automation, Pasadena, CA, USA, May 2008, pp. 862-867. doi:10.1109/ROBOT.2008.4543313 Paper II E. Naerum, J. Cornellà and O.J. Elle. Contact force estimation for backdrivable robotic manipulators with coupled friction IE...

  15. Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  16. Dynamics of forced biopolymer translocation

    CERN Document Server

    Lehtola, V V; Kaski, K; 10.1209/0295-5075/85/58006

    2009-01-01

    We present results from our simulations of biopolymer translocation in a solvent which explain the main experimental findings. The forced translocation can be described by simple force balance arguments for the relevant range of pore potentials in experiments and biological systems. Scaling of translocation time with polymer length varies with pore force and friction. Hydrodynamics affects this scaling and significantly reduces translocation times.

  17. Interfacial forces between silica surfaces measured by atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    DUAN Jinming

    2009-01-01

    Colloidal particle stability and some other interfacial phenomena are governed by interfacial force interactions. The two well known forces are van der Waals force and electrostatic force, as documented by the classical Derjaguin, Landau, Verwey and Overbeek (DLVO) theory. Moreover, advances in modern instrumentation and colloid science suggested that some short-ranged forces or structure forces are important for relevant colloidal systems. The interfacial and/or molecular forces can be measured as a resultant force as function of separation distance by atomic force microscopy (AFM) colloid probe. This article presents a discussion on AFM colloid probe measurement of silica particle and silica wafer surfaces in solutions with some technical notifications in measurement and data convolution mechanisms. The measured forces are then analyzed and discussed based on the 'constant charge' and 'constant potential' models of DLVO theory. The difference between the prediction of DLVO theory and the measured results indicates that there is a strong short-range structure force between the two hydrophilic surfaces, even at extremely low ionic concentration, such as Milli-Q water purity solution.

  18. Reconstructing the distributed force on an atomic force microscope cantilever

    Science.gov (United States)

    Wagner, Ryan; Killgore, Jason

    2017-03-01

    A methodology is developed to reconstruct the force applied to an atomic force microscopy (AFM) cantilever given the shape in which it vibrates. This is accomplished by rewriting Bernoulli–Euler beam theory such that the force on the cantilever is approximated as a linear superposition of the theoretical cantilever eigenmodes. The weighting factors in this summation are calculated from the amplitude and phase measured along the length of the cantilever. The accuracy of the force reconstruction is shown to depend on the frequency at which the measurement is performed, the number of discrete points measured along the length of the cantilever, and the signal-to-noise ratio of the measured signal. In contrast to other AFM force reconstruction techniques, this method can reconstruct the distribution of force applied over the length of the AFM cantilever. However, this method performs poorly for localized forces applied to the cantilever, such as is typical of most tip–sample interaction forces. Proof of concept experiments are performed on an electrostatically excited cantilever and the expected force distribution is recovered. This force reconstruction technique offers previously unavailable insight into the distributed forces experienced by an AFM cantilever.

  19. Interfacial forces between silica surfaces measured by atomic force microscopy.

    Science.gov (United States)

    Duan, Jinming

    2009-01-01

    Colloidal particle stability and some other interfacial phenomena are governed by interfacial force interactions. The two well known forces are van der Waals force and electrostatic force, as documented by the classical Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory. Moreover, advances in modern instrumentation and colloid science suggested that some short-ranged forces or structure forces are important for relevant colloidal systems. The interfacial and/or molecular forces can be measured as a resultant force as function of separation distance by atomic force microscopy (AFM) colloid probe. This article presents a discussion on AFM colloid probe measurement of silica particle and silica wafer surfaces in solutions with some technical notifications in measurement and data convolution mechanisms. The measured forces are then analyzed and discussed based on the 'constant charge' and 'constant potential' models of DLVO theory. The difference between the prediction of DLVO theory and the measured results indicates that there is a strong short-range structure force between the two hydrophilic surfaces, even at extremely low ionic concentration, such as Milli-Q water purity solution.

  20. Proximal arm kinematics affect grip force-load force coordination.

    Science.gov (United States)

    Vermillion, Billy C; Lum, Peter S; Lee, Sang Wook

    2015-10-01

    During object manipulation, grip force is coordinated with load force, which is primarily determined by object kinematics. Proximal arm kinematics may affect grip force control, as proximal segment motion could affect control of distal hand muscles via biomechanical and/or neural pathways. The aim of this study was to investigate the impact of proximal kinematics on grip force modulation during object manipulation. Fifteen subjects performed three vertical lifting tasks that involved distinct proximal kinematics (elbow/shoulder), but resulted in similar end-point (hand) trajectories. While temporal coordination of grip and load forces remained similar across the tasks, proximal kinematics significantly affected the grip force-to-load force ratio (P = 0.042), intrinsic finger muscle activation (P = 0.045), and flexor-extensor ratio (P muscles and the elbow joint cannot fully explain the observed changes, as task-related changes in intrinsic hand muscle activation were greater than in extrinsic hand muscles. Rather, between-task variation in grip force (highest during task 3) appears to contrast to that in shoulder joint velocity/acceleration (lowest during task 3). These results suggest that complex neural coupling between the distal and proximal upper extremity musculature may affect grip force control during movements, also indicated by task-related changes in intermuscular coherence of muscle pairs, including intrinsic finger muscles. Furthermore, examination of the fingertip force showed that the human motor system may attempt to reduce variability in task-relevant motor output (grip force-to-load force ratio), while allowing larger fluctuations in output less relevant to task goal (shear force-to-grip force ratio).

  1. Reducing Air Force Fighter Pilot Shortages

    Science.gov (United States)

    2015-12-31

    experienced flight leaders. New fighter pilots coming directly out of SUPT and IFF require 500 flying hours to become designated as experienced. In...rated officers—an imperfect match of human capital to requirements. Further Reductions Options to reduce requirements, listed in Chapter Two, include...progress. The hours required for OCO support are typically additive and funded by the Transportation Working Capital Fund (TWCF) rather than by Air Force

  2. Force and motion

    CERN Document Server

    Robertson, William C

    2002-01-01

    Intimidated by inertia? Frightened by forces? Mystified by Newton s law of motion? You re not alone and help is at hand. The stop Faking It! Series is perfect for science teachers, home-schoolers, parents wanting to help with homework all of you who need a jargon-free way to learn the background for teaching middle school physical science with confidence. With Bill Roberton as your friendly, able but somewhat irreverent guide, you will discover you CAN come to grips with the basics of force and motion. Combining easy-to-understand explanations with activities using commonly found equipment, this book will lead you through Newton s laws to the physics of space travel. The book is as entertaining as it is informative. Best of all, the author understands the needs of adults who want concrete examples, hands-on activities, clear language, diagrams and yes, a certain amount of empathy. Ideas For Use Newton's laws, and all of the other motion principles presented in this book, do a good job of helping us to underst...

  3. Can dual processing theory explain physics students' performance on the Force Concept Inventory?

    Science.gov (United States)

    Wood, Anna K.; Galloway, Ross K.; Hardy, Judy

    2016-12-01

    According to dual processing theory there are two types, or modes, of thinking: system 1, which involves intuitive and nonreflective thinking, and system 2, which is more deliberate and requires conscious effort and thought. The Cognitive Reflection Test (CRT) is a widely used and robust three item instrument that measures the tendency to override system 1 thinking and to engage in reflective, system 2 thinking. Each item on the CRT has an intuitive (but wrong) answer that must be rejected in order to answer the item correctly. We therefore hypothesized that performance on the CRT may give useful insights into the cognitive processes involved in learning physics, where success involves rejecting the common, intuitive ideas about the world (often called misconceptions) and instead carefully applying physical concepts. This paper presents initial results from an ongoing study examining the relationship between students' CRT scores and their performance on the Force Concept Inventory (FCI), which tests students' understanding of Newtonian mechanics. We find that a higher CRT score predicts a higher FCI score for both precourse and postcourse tests. However, we also find that the FCI normalized gain is independent of CRT score. The implications of these results are discussed.

  4. Simulation and Experimental Research on Cutting Force of Turning Titanium Alloy

    Directory of Open Access Journals (Sweden)

    Zheng Qingchun

    2015-01-01

    Full Text Available This paper mainly establishes a two-dimensional model about the YG8 carbide tool turning TC4 titanium alloy on the basis of ABAQUS. The cutting force of the simulation model was verified by the turning experiment, and the relationships of cutting force with cutting speed, feed rate and rake angle of cutting edge in the model were studied. A prediction model of main cutting force related to cutting speed, feed rate and rake angle was obtained by central composite experiment. Studies have shown that the difference between the cutting force acquired by simulation and by experiment was less than 10%; in a certain range, the cutting force increased with the feed rate, the cutting force decreased with the increase of cutting speed and rake angle, and the influence of feed rate to cutting force was most significant.

  5. Effects of oncoming target velocities on rapid force production and accuracy of force production intensity and timing.

    Science.gov (United States)

    Ohta, Yoichi

    2016-12-12

    The present study aimed to clarify the effects of oncoming target velocities on the ability of rapid force production and accuracy and variability of simultaneous control of both force production intensity and timing. Twenty male participants (age: 21.0 ± 1.4 years) performed rapid gripping with a handgrip dynamometer to coincide with the arrival of an oncoming target by using a horizontal electronic trackway. The oncoming target velocities were 4, 8, and 12 m · s(-1), which were randomly produced. The grip force required was 30% of the maximal voluntary contraction. Although the peak force (Pf) and rate of force development (RFD) increased with increasing target velocity, the value of the RFD to Pf ratio was constant across the 3 target velocities. The accuracy of both force production intensity and timing decreased at higher target velocities. Moreover, the intrapersonal variability in temporal parameters was lower in the fast target velocity condition, but constant variability in 3 target velocities was observed in force intensity parameters. These results suggest that oncoming target velocity does not intrinsically affect the ability for rapid force production. However, the oncoming target velocity affects accuracy and variability of force production intensity and timing during rapid force production.

  6. Control Of Motor Unit Firing During Step-Like Increases In Voluntary Force

    Directory of Open Access Journals (Sweden)

    Xiaogang eHu

    2014-09-01

    Full Text Available In most skeletal muscles, force is generated by a combination of motor unit (MU recruitment and increases in the firing rate of previously active MUs. Two contrasting patterns of firing rate organization have been reported. In the first pattern, the earliest recruited MUs reach the highest firing rates as force is increased, and later recruited MUs fire at lower rates. When firing rate of multiple MUs are superimposed, these rate trajectories form a concentric layered profile termed ‘onion skin’. In the second pattern, called ‘reverse onion skin’, later recruited MUs reach higher firing rates, and crossing of firing rate trajectories for recorded MUs is common (although such trajectories are assembled routinely from different trials. Our present study examined the firing rate organization of concurrently active MUs of the first dorsal interosseous muscle during serial, step-like increases in isometric abduction forces. We used a surface sensor array coupled with MU discrimination algorithms to characterize MU firing patterns. Our objective was to determine whether ‘onion skin’ profiles are contingent upon the force trajectory of the motor task, examined here using step-like increases of force output, and also whether they are manifested at different force levels.Our results revealed that the overall ‘onion skin’ firing rate profile was retained as the force level increased with each force step up to 15% MVC. However, the distribution of firing rates across MUs was compressed with increasing force, and overlapping firing rate of units were observed. This rate compression was largely due to rate saturation of the relatively high frequency discharging MUs.Our results reflect flexible firing patterns across MUs at different levels of excitation drive. It is also evident that many units did not follow all the step increases consistently. This failure to track firing rate increases at higher forces could be due to an intrinsically

  7. Anomalous EMG-force relations during low-force isometric tasks in hemiparetic stroke survivors.

    Science.gov (United States)

    Suresh, Nina L; Concepcion, Nicole S; Madoff, Janina; Rymer, W Z

    2015-01-01

    Hemispheric brain injury resulting from a stroke is often accompanied by muscle weakness in contralateral limbs. In neurologically intact subjects, appropriate motoneuronal recruitment and rate modulation are utilized to optimize muscle force production. In the present study, we sought to determine whether weakness in an affected hand muscle in stroke survivors is partially attributable to alterations in the control of muscle activation. Specifically, our goal was to characterize whether the surface EMG amplitude was systematically larger as a function of (low) force in paretic hand muscles as compared to contralateral muscles in the same subject. We tested a multifunctional muscle, the first dorsal interosseous (FDI), in multiple directions about the second metacarpophalangeal joint in ten hemiparetic and six neurologically intact subjects. In six of the ten stroke subjects, the EMG-force slope was significantly greater on the affected side as compared to the contralateral side, as well as compared to neurologically intact subjects. An unexpected set of results was a nonlinear relation between recorded EMG and generated force commonly observed in the paretic FDI, even at very low-force levels. We discuss possible experimental as well as physiological factors that may contribute to an increased EMG-force slope, concluding that changes in motor unit (MU) control are the most likely reasons for the observed changes.

  8. Theory of dynamic force spectroscopy for kinetochore-microtubule attachments: rupture force distribution

    CERN Document Server

    Ghanti, Dipanwita

    2016-01-01

    Application of pulling force, under force-clamp conditions, to kinetochore-microtubule attachments {\\it in-vitro} revealed a catch-bond-like behavior. In an earlier paper ({\\it Sharma et al. Phys. Biol. (2014)} the physical origin of this apparently counter-intuitive phenomenon was traced to the nature of the force-dependence of the (de-)polymerization kinetics of the microtubules. In this brief communication that work is extended to situations where the external forced is ramped up till the attachment gets ruptured. In spite of the fundamental differences in the underlying mechanisms, the trend of variation of the rupture force distribution observed in our model kinetochore-microtubule attachment with the increasing loading rate is qualitatively similar to that displayed by the catch bonds formed in some other ligand-receptor systems. Our theoretical predictions can be tested experimentally by a straightforward modification of the protocol for controlling the force in the optical trap set up that was used in...

  9. Force in women's sexual fantasies.

    Science.gov (United States)

    Strassberg, D S; Lockerd, L K

    1998-08-01

    Attitudinal and experiential correlates of sexual fantasies involving force or coercion against the fantasizer were studied in 137 college women. Results revealed that (i) virtually every woman reported engaging in sexual fantasy on a regular basis, (ii) more than half the subjects reported having engaged in a force fantasy, (iii) those reporting force fantasies scored as less sexually guilty and more erotophilic than those not reporting such fantasies. Those reporting force fantasies also had more sexual experience and engaged in more fantasizing of the nonforce type than the other subjects. A history of exposure to sexual force or coercion was unrelated to the report of force fantasies. Taken together, these findings are offered in support of the hypothesis that the occurrence of force fantasies, rather than resulting from an attempt to deal with sexual guilt, represents one of a number of ways in which some women demonstrate a relatively open, unrestricted, and varied approach to their sexuality.

  10. Force-stabilizing synergies in motor tasks involving two actors

    Science.gov (United States)

    Solnik, Stanislaw; Reschechtko, Sasha; Wu, Yen-Hsun; Zatsiorsky, Vladimir M.; Latash, Mark L.

    2015-01-01

    We investigated the ability of two persons to produce force-stabilizing synergies in accurate multi-finger force production tasks under visual feedback on the total force only. The subjects produced a time profile of total force (the sum of two hand forces in one-person tasks and the sum of two subject forces in two-person tasks) consisting of a ramp-up, steady-state, and ramp-down segments; the steady-state segment was interrupted in the middle by a quick force pulse. Analyses of the structure of inter-trial finger force variance, motor equivalence, anticipatory synergy adjustments (ASAs), and the unintentional drift of the sharing pattern were performed. The two-person performance was characterized by a dramatically higher amount of inter-trial variance that did not affect total force, higher finger force deviations that did not affect total force (motor equivalent deviations), shorter ASAs, and larger drift of the sharing pattern. The rate of sharing pattern drift correlated with the initial disparity between the forces produced by the two persons (or two hands). The drift accelerated following the quick force pulse. Our observations show that sensory information on the task-specific performance variable is sufficient for the organization of performance-stabilizing synergies. They suggest, however, that two actors are less likely to follow a single optimization criterion as compared to a single performer. The presence of ASAs in the two-person condition might reflect fidgeting by one or both of the subjects. We discuss the characteristics of the drift in the sharing pattern as reflections of different characteristic times of motion within the sub-spaces that affect and do not affect salient performance variables. PMID:26105756

  11. Atomic Force Microscope Mediated Chromatography

    Science.gov (United States)

    Anderson, Mark S.

    2013-01-01

    sliding plate system, consisting of two flat surfaces, one of which has a recessed channel. A fluid flow is produced by axially sliding one plate past another, where the fluid has mechanical shear forces imposed at each point along the channel length. The shear-induced flow rates are very reproducible, and do not have pressure or voltage gradient limitations. SDC opens up a new range of enhanced separation kinetics by permitting the sample confinement with submicron dimensions. Small, highly confined liquid is advantageous for chromatographic separation because the separation rate is known to scale according to the square of the confined sample diameter. In addition, because shear-driven flows are not limited by fluid velocity, shear-driven liquid chromatography may provide up to 100,000 plate efficiency.

  12. Mechanically-forced dynamos (Invited)

    Science.gov (United States)

    Le Bars, M.

    2013-12-01

    It is a commonly accepted hypothesis that convection is responsible for planetary dynamos. However, the validity of the convective dynamo model can be questioned in various planets and moons as well as in asteroids, where the constraints from thermal evolution and compositional core models are sometimes difficult to reconcile with available data from paleomagnetism and in situ measurements. Over the last few years, researches have thus been pursued to find alternative mechanisms for sustaining intense three-dimensional motions in liquid cores, a necessary ingredient for planetary dynamo. In particular, mechanical forcings driven by libration, precession, nutation and tides, have received a renewed interest, following the first studies by Malkus in the 60's. A huge reservoir of energy is available in the rotational and orbital motions of all planetary systems. If planetary bodies were completely rigid and rotating at a constant spin rate, their fluid layers in the absence of convection would also behave rigidly and follow the spin of their boundaries. But small periodic perturbations of the shape of the core/mantle boundary (i.e. dynamic tides) and/or small periodic perturbations of the direction of the spin vector (i.e. precession and nutation) and/or small periodic perturbations of the spin rate (i.e. libration) systematically perturb this rigid state. Then, each of these small perturbations is capable of triggering instabilities in fluid layers, conveying energy from the spin and orbital motions to drive intense three-dimensional flows in the liquid cores. With the view to establish a general framework for planetary applications, I will present here the basic physical ingredients of these instabilities, which involve a resonance between the considered mechanical forcing and two inertial waves of the core. I will then review the numerical and experimental validations of this generic principle, and the few magnetohydrodynamic validations of their dynamo capacity

  13. Irrigation as an Historical Climate Forcing

    Science.gov (United States)

    Cook, Benjamin I.; Shukla, Sonali P.; Puma, Michael J.; Nazarenko, Larissa S.

    2014-01-01

    Irrigation is the single largest anthropogenic water use, a modification of the land surface that significantly affects surface energy budgets, the water cycle, and climate. Irrigation, however, is typically not included in standard historical general circulation model (GCM) simulations along with other anthropogenic and natural forcings. To investigate the importance of irrigation as an anthropogenic climate forcing, we conduct two 5-member ensemble GCM experiments. Both are setup identical to the historical forced (anthropogenic plus natural) scenario used in version 5 of the Coupled Model Intercomparison Project, but in one experiment we also add water to the land surface using a dataset of historically estimated irrigation rates. Irrigation has a negligible effect on the global average radiative balance at the top of the atmosphere, but causes significant cooling of global average surface air temperatures over land and dampens regional warming trends. This cooling is regionally focused and is especially strong in Western North America, the Mediterranean, the Middle East, and Asia. Irrigation enhances cloud cover and precipitation in these same regions, except for summer in parts of Monsoon Asia, where irrigation causes a reduction in monsoon season precipitation. Irrigation cools the surface, reducing upward fluxes of longwave radiation (increasing net longwave), and increases cloud cover, enhancing shortwave reflection (reducing net shortwave). The relative magnitude of these two processes causes regional increases (northern India) or decreases (Central Asia, China) in energy availability at the surface and top of the atmosphere. Despite these changes in net radiation, however, climate responses are due primarily to larger magnitude shifts in the Bowen ratio from sensible to latent heating. Irrigation impacts on temperature, precipitation, and other climate variables are regionally significant, even while other anthropogenic forcings (anthropogenic aerosols

  14. Irrigation as an historical climate forcing

    Science.gov (United States)

    Cook, Benjamin I.; Shukla, Sonali P.; Puma, Michael J.; Nazarenko, Larissa S.

    2015-03-01

    Irrigation is the single largest anthropogenic water use, a modification of the land surface that significantly affects surface energy budgets, the water cycle, and climate. Irrigation, however, is typically not included in standard historical general circulation model (GCM) simulations along with other anthropogenic and natural forcings. To investigate the importance of irrigation as an anthropogenic climate forcing, we conduct two 5-member ensemble GCM experiments. Both are setup identical to the historical forced (anthropogenic plus natural) scenario used in version 5 of the Coupled Model Intercomparison Project, but in one experiment we also add water to the land surface using a dataset of historically estimated irrigation rates. Irrigation has a negligible effect on the global average radiative balance at the top of the atmosphere, but causes significant cooling of global average surface air temperatures over land and dampens regional warming trends. This cooling is regionally focused and is especially strong in Western North America, the Mediterranean, the Middle East, and Asia. Irrigation enhances cloud cover and precipitation in these same regions, except for summer in parts of Monsoon Asia, where irrigation causes a reduction in monsoon season precipitation. Irrigation cools the surface, reducing upward fluxes of longwave radiation (increasing net longwave), and increases cloud cover, enhancing shortwave reflection (reducing net shortwave). The relative magnitude of these two processes causes regional increases (northern India) or decreases (Central Asia, China) in energy availability at the surface and top of the atmosphere. Despite these changes in net radiation, however, climate responses are due primarily to larger magnitude shifts in the Bowen ratio from sensible to latent heating. Irrigation impacts on temperature, precipitation, and other climate variables are regionally significant, even while other anthropogenic forcings (anthropogenic aerosols

  15. Forced Migration: Refugee Populations

    Science.gov (United States)

    Boyle, Joyceen S.

    2015-01-01

    Undocumented migration is a global phenomenon that manifests in various contexts. This article describes the impact of the movement of large numbers of people in several African countries, producing a unique type of migrant—the refugee. We describe issues that refugee movements create on fragile health care systems, situations that precipitate refugee movements, certain human rights violations that are of particular concern such as gender based violence (GBV) and child soldiers, and lastly, implications for nursing practice and policy. We use examples from several countries in Sub-Saharan Africa, including the Democratic Republic of the Congo, Rwanda, Liberia, Sierra Leone, and Mozambique. Drawing on key documents from the United Nations High Commissioner for Refugees, current literature, as well as the international experience of the authors, this article presents an overview of forced migration and discusses opportunities for nurses to impact research, practice and policy related to refugee health. PMID:25645484

  16. [Galileo and centrifugal force].

    Science.gov (United States)

    Vilain, Christiane

    This work intends to focus on Galileo's study of what is now called "centrifugal force," within the framework of the Second Day of his Dialogo written in 1632, rather than on the previously published commentaries on the topic. Galileo proposes three geometrical demonstrations in order to prove that gravity will always overcome centrifugalforce, and that the potential rotation of the Earth, whatever its speed, cannot in any case project objects beyond it. Each of these demonstrations must consequently contain an error and it has seemed to us that the first one had not been understood up until now. Our analysis offers an opportunity to return to Galileo's geometrical representation of dynamical questions; actually, we get an insight into the sophistication of Galileo's practices more than into his mistakes. Our second point, concerning the historiography of the problem, shows an evolution from anachronic critics to more contextual considerations, in the course of the second half of the twentieth century.

  17. Forced marriage, forced sex: the perils of childhood for girls.

    Science.gov (United States)

    Ouattara, M; Sen, P; Thomson, M

    1998-11-01

    A recently formed interagency Forum on the Rights of Girls and Women in Marriage is investigating the widespread problem of nonconsensual marriage and forced sex and advocating for legislative and policy initiatives. This article reviews three research projects in this area: research by Anti-Slavery International on child marriage in parts of West Africa, an investigation by Save the Children of children's views of early marriage, and research conducted by CHANGE on women's resistance to domestic violence in Calcutta, India. Girls who marry before 15 years of age are more likely to be illiterate than their older counterparts, more likely to be dowry payment brides, less likely to come into contact with development projects, have higher rates of infant mortality, and are most vulnerable to sexual violence. In many cases, intercourse is initiated before the girl begins to menstruate. Although adult women also face sexual violence within marriage, this problem is all the more traumatic for girls who lack any information about sexuality. Sex with girls below a certain age is usually covered by rape legislation, but, in countries such as India, this is mitigated by the religiously defined personal laws. The absence of adequate legal and policy action frameworks to deal with the rights of girls, coupled with the lack of sanctions against these abuses, comprise state complicity and neglect of duty under international law to this vulnerable group.

  18. Malaria transmission rates estimated from serological data.

    OpenAIRE

    Burattini, M. N.; Massad, E; Coutinho, F. A.

    1993-01-01

    A mathematical model was used to estimate malaria transmission rates based on serological data. The model is minimally stochastic and assumes an age-dependent force of infection for malaria. The transmission rates estimated were applied to a simple compartmental model in order to mimic the malaria transmission. The model has shown a good retrieving capacity for serological and parasite prevalence data.

  19. Changes in muscle force-length properties affect the early rise of force in vivo

    DEFF Research Database (Denmark)

    Blazevich, Anthony J; Cannavan, Dale; Horne, Sara

    2009-01-01

    Changes in contractile rate of force development (RFD), measured within a short time interval from contraction initiation, were measured after a period of strength training that led to increases in muscle fascicle length but no measurable change in neuromuscular activity. The relationship between...... training-induced shifts in the moment-angle relation and changes in RFD measured to 30 ms (i.e., early) and 200 ms (i.e., late) from the onset of isometric knee extension force were examined; shifts in the moment-angle relation were used as an overall measure of changes in quadriceps muscle fascicle length...

  20. Chemical energetics of force development, force maintenance, and relaxation in mammalian smooth muscle

    OpenAIRE

    1980-01-01

    High-energy phosphate utilization (delta approximately P) associated with force development, force maintenance, and relaxation has been determined during single isometric tetani in the rabbit taenia coli. ATP resynthesis from glycolysis and respiration was stopped without deleterious effects on the muscle. At 18 degrees C and a muscle length of 95% l0, the resting rate of energy utilization is 1.8 +/- 0.2 nmol/g . s-1, or 0.85 +/- 0.2 mmol approximately P/mol of total creatine (Ct) . s-1, whe...

  1. Sensor Fusion of Force and Acceleration for Robot Force Control

    OpenAIRE

    Gámez García, Javier; Robertsson, Anders; Gómez Ortega, Juan; Johansson, Rolf

    2004-01-01

    In this paper, robotic sensor fusion of acceleration and force measurement is considered. We discuss the problem of using accelerometers close to the end-effectors of robotic manipulators and how it may improve the force control performance. We introduce a new model-based observer approach to sensor fusion of information from various different sensors. During contact transition, accelerometers and force sensors play a very important role and it can overcome many of the difficulties of uncerta...

  2. Theory of Casimir Forces without the Proximity-Force Approximation.

    Science.gov (United States)

    Lapas, Luciano C; Pérez-Madrid, Agustín; Rubí, J Miguel

    2016-03-18

    We analyze both the attractive and repulsive Casimir-Lifshitz forces recently reported in experimental investigations. By using a kinetic approach, we obtain the Casimir forces from the power absorbed by the materials. We consider collective material excitations through a set of relaxation times distributed in frequency according to a log-normal function. A generalized expression for these forces for arbitrary values of temperature is obtained. We compare our results with experimental measurements and conclude that the model goes beyond the proximity-force approximation.

  3. Automated force controller for amplitude modulation atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miyagi, Atsushi, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr; Scheuring, Simon, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr [U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13009 Marseille (France)

    2016-05-15

    Atomic Force Microscopy (AFM) is widely used in physics, chemistry, and biology to analyze the topography of a sample at nanometer resolution. Controlling precisely the force applied by the AFM tip to the sample is a prerequisite for faithful and reproducible imaging. In amplitude modulation (oscillating) mode AFM, the applied force depends on the free and the setpoint amplitudes of the cantilever oscillation. Therefore, for keeping the applied force constant, not only the setpoint amplitude but also the free amplitude must be kept constant. While the AFM user defines the setpoint amplitude, the free amplitude is typically subject to uncontrollable drift, and hence, unfortunately, the real applied force is permanently drifting during an experiment. This is particularly harmful in biological sciences where increased force destroys the soft biological matter. Here, we have developed a strategy and an electronic circuit that analyzes permanently the free amplitude of oscillation and readjusts the excitation to maintain the free amplitude constant. As a consequence, the real applied force is permanently and automatically controlled with picoNewton precision. With this circuit associated to a high-speed AFM, we illustrate the power of the development through imaging over long-duration and at various forces. The development is applicable for all AFMs and will widen the applicability of AFM to a larger range of samples and to a larger range of (non-specialist) users. Furthermore, from controlled force imaging experiments, the interaction strength between biomolecules can be analyzed.

  4. Keep flexible - Keep switching! The influence of forced task switching on voluntary task switching.

    Science.gov (United States)

    Fröber, Kerstin; Dreisbach, Gesine

    2017-05-01

    Goal directed behavior depends on a dynamic balance between cognitive flexibility and stability. Identifying factors that modulate the balance between these control states is therefore of major interest for the understanding of human action control. In two experiments we used a hybrid paradigm combining forced- and free-choice task switching and measured spontaneous voluntary switch rate (VSR) as an indicator of cognitive flexibility. In Experiment 1 participants were free to choose a given task on 75%, 50%, or 25% of all trials. In the remaining forced-choice trials task repetitions and switches were roughly equally distributed. Results showed that VSR increases with increasing proportion of forced choices. To clarify whether the frequency of forced choices per se or the frequency of forced task switches in particular drives this effect we conducted Experiment 2. In a fully orthogonal between design participants were free to choose a given task on 75% or 25% of all trials with a predetermined switch rate in the remaining forced-choice trials of 75% or 25%, respectively. Results revealed an interaction of both manipulations: The highest VSR was found for the combination of 75% forced-choice trials with 75% forced switch rate, while VSR for 75% forced-choice trials with 25% forced switch rate was still higher than VSRs in both conditions with 25% forced-choice trials. This suggests that a context of frequent forced task switching changes global control parameters towards more flexible behavior. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Molecular model for force production and transmission during vertebrate gastrulation.

    Science.gov (United States)

    Pfister, Katherine; Shook, David R; Chang, Chenbei; Keller, Ray; Skoglund, Paul

    2016-02-15

    Vertebrate embryos undergo dramatic shape changes at gastrulation that require locally produced and anisotropically applied forces, yet how these forces are produced and transmitted across tissues remains unclear. We show that depletion of myosin regulatory light chain (RLC) levels in the embryo blocks force generation at gastrulation through two distinct mechanisms: destabilizing the myosin II (MII) hexameric complex and inhibiting MII contractility. Molecular dissection of these two mechanisms demonstrates that normal convergence force generation requires MII contractility and we identify a set of molecular phenotypes correlated with both this failure of convergence force generation in explants and of blastopore closure in whole embryos. These include reduced rates of actin movement, alterations in C-cadherin dynamics and a reduction in the number of polarized lamellipodia on intercalating cells. By examining the spatial relationship between C-cadherin and actomyosin we also find evidence for formation of transcellular linear arrays incorporating these proteins that could transmit mediolaterally oriented tensional forces. These data combine to suggest a multistep model to explain how cell intercalation can occur against a force gradient to generate axial extension forces. First, polarized lamellipodia extend mediolaterally and make new C-cadherin-based contacts with neighboring mesodermal cell bodies. Second, lamellipodial flow of actin coalesces into a tension-bearing, MII-contractility-dependent node-and-cable actin network in the cell body cortex. And third, this actomyosin network contracts to generate mediolateral convergence forces in the context of these transcellular arrays.

  6. Hispanics in the Labor Force: A Conference Report.

    Science.gov (United States)

    Borjas, George, Ed.; Tienda, Marta, Ed.

    Hispanics in the U.S. labor force are the subject of the studies in this volume. After an introduction by George J. Borjas and Marta Tienda, the first three papers focus on the same issue: the determination of wage rates for Hispanics and comparison of Hispanic and non-Hispanic wage rates. Cordelia Reimers compares the situation for Black, White,…

  7. A Study of Slovenian Armed Forces Ammunition Forecasting Methodology

    Science.gov (United States)

    2012-12-14

    multiplying factor that addressed the operation type, either defense or offence , with additional variants depending on high, moderate, or low...level planning method, consumption rates based on NATO consumption rates for defense, offence , and delay operation. SAF Force Command is...systems, detection and kill probabilities, 32 terrain and environmental data, the Combat Sample Generator will use doctrine and tactics to describe the

  8. Microphotonic Forces From Superfluid Flow

    CERN Document Server

    McAuslan, D L; Baker, C; Sachkou, Y; He, X; Sheridan, E; Bowen, W P

    2015-01-01

    In cavity optomechanics, radiation pressure and photothermal forces are widely utilized to cool and control micromechanical motion, with applications ranging from precision sensing and quantum information to fundamental science. Here, we realize an alternative approach to optical forcing based on superfluid flow and evaporation in response to optical heating. We demonstrate optical forcing of the motion of a cryogenic microtoroidal resonator at a level of 1.46 nN, roughly one order of magnitude larger than the radiation pressure force. We use this force to feedback cool the motion of a microtoroid mechanical mode to 137 mK. The photoconvective forces demonstrated here provide a new tool for high bandwidth control of mechanical motion in cryogenic conditions, and have the potential to allow efficient transfer of electromagnetic energy to motional kinetic energy.

  9. Force Limited Vibration Testing Monograph

    Science.gov (United States)

    Scharton, Terry D.

    1997-01-01

    The practice of limiting the shaker force in vibration tests was investigated at the NASA Jet Propulsion Laboratory (JPL) in 1990 after the mechanical failure of an aerospace component during a vibration test. Now force limiting is used in almost every major vibration test at JPL and in many vibration tests at NASA Goddard Space Flight Center (GSFC) and at many aerospace contractors. The basic ideas behind force limiting have been in the literature for several decades, but the piezo-electric force transducers necessary to conveniently implement force limiting have been available only in the last decade. In 1993, funding was obtained from the NASA headquarters Office of Chief Engineer to develop and document the technology needed to establish force limited vibration testing as a standard approach available to all NASA centers and aerospace contractors. This monograph is the final report on that effort and discusses the history, theory, and applications of the method in some detail.

  10. A Solar System Survey of Forced Librations in Longitude

    Science.gov (United States)

    Cornstock, Robert L.; Bills, Bruce G.

    2003-01-01

    Forced librations are periodic rotational rate variations due to gravitational interactions with an orbital partner. We have developed an analytic theory capable of calculating expected amplitudes of forced librations for nonresonant rotators as well as for bodies existing in a spin-orbit resonance. The theory has been applied to 34 solar system bodies, including terrestrial planets, planetary satellites, and the asteroid Eros. Parameters governing libration amplitude are the body s orbital eccentricity, moment difference, and the ratio of its spin rate to its orbital rate. In each case the largest libration amplitude is associated with the forcing frequency 2 (p - 1) n, where n is the orbital mean motion and p is the spin/orbit rate ratio. This dominant frequency is simply semidiurnal as seen from the position of the torquing body. The maximum libration angular amplitude is 1.3 x 10(exp -2) radians for Thebe, and the maximum mean equatorial displacement is 1.4 km for Mimas.

  11. Force-Degradation Pattern of Six Different Orthodontic Elastomeric Chains

    Directory of Open Access Journals (Sweden)

    AH Mirhashemi

    2012-01-01

    Full Text Available Objective: An ideal orthodontic force system should exert continuous light force. Thus, many efforts have been made to improve the memory characteristics of elastomeric chains. The aim of this study was to compare elastomeric chains (ECs claimed by their manufacturers to offer high memory with traditional ones according to their force-extension diagrams.Materials and Methods: In this in-vitro study, ECs were divided into six groups, each containing 40 pieces of chain, from three brands (American Orthodontics, GAC and Ortho-Technology. Each brand was divided into two groups with respect to their claimed characteristics (with or without memory. Each sample was stretched to twice its original length and kept constant in 37°C distilled water. Force-extension diagrams were drawn by universal testing machine at 0,1,8,24,72 hours and 1, 2, 4-week intervals. Additionally, the amounts of elongation required to deliver 200 g force were calculated. To compare the results, ANOVA and Tukey tests were performed.Results: Force-decay rate was significantly different between traditional and memory chains (p<0.05. For traditional chains, there was a substantial decay in force in the first hour and 30-40% of the force was retained at 4 weeeks. The memory chains demonstrated more constant force and retained 60% of the force. The maximum amount of elongation required to deliver 200 g force belonged to American Orthodontics memory chains (61.9% after 24hr and the minimum to Ortho-Technology ECs (23.4% initially.Conclusion: Memory chains exhibited superior mechanical properties compared to traditional ones. For delivering the same force, memory chains required more elongation. Memory chains of GAC and American Orthodontics showed better characteristics among all chains.

  12. Forced Smoking Abstinence

    Science.gov (United States)

    Clarke, Jennifer G.; Stein, L. A. R.; Martin, Rosemarie A.; Martin, Stephen A.; Parker, Donna; Lopes, Cheryl E.; McGovern, Arthur R.; Simon, Rachel; Roberts, Mary; Friedman, Peter; Bock, Beth

    2015-01-01

    Importance Millions of Americans are forced to quit smoking as they enter tobacco-free prisons and jails, but most return to smoking within days of release. Interventions are needed to sustain tobacco abstinence after release from incarceration. Objective To evaluate the extent to which the WISE intervention (Working Inside for Smoking Elimination), based on motivational interviewing (MI) and cognitive behavioral therapy (CBT), decreases relapse to smoking after release from a smoke-free prison. Design Participants were recruited approximately 8 weeks prior to their release from a smoke-free prison and randomized to 6 weekly sessions of either education videos (control) or the WISE intervention. Setting A tobacco-free prison in the United States. Participants A total of 262 inmates (35% female). Main Outcome Measure Continued smoking absti nence was defined as 7-day point-prevalence abstinence validated by urine cotinine measurement. Results At the 3-week follow-up, 25% of participants in the WISE intervention (31 of 122) and 7% of the control participants (9 of 125) continued to be tobacco abstinent (odds ratio [OR], 4.4; 95% CI, 2.0-9.7). In addition to the intervention, Hispanic ethnicity, a plan to remain abstinent, and being incarcerated for more than 6 months were all associated with increased likelihood of remaining abstinent. In the logistic regression analysis, participants randomized to the WISE intervention were 6.6 times more likely to remain tobacco abstinent at the 3-week follow up than those randomized to the control condition (95% CI, 2.5-17.0). Nonsmokers at the 3-week follow-up had an additional follow-up 3 months after release, and overall 12% of the participants in the WISE intervention (14 of 122) and 2% of the control participants (3 of 125) were tobacco free at 3 months, as confirmed by urine cotinine measurement (OR, 5.3; 95% CI, 1.4-23.8). Conclusions and Relevance Forced tobacco abstinence alone during incarceration has little impact on

  13. MEMS Bragg grating force sensor

    DEFF Research Database (Denmark)

    Reck, Kasper; Thomsen, Erik Vilain; Hansen, Ole

    2011-01-01

    We present modeling, design, fabrication and characterization of a new type of all-optical frequency modulated MEMS force sensor based on a mechanically amplified double clamped waveguide beam structure with integrated Bragg grating. The sensor is ideally suited for force measurements in harsh...... environments and for remote and distributed sensing and has a measured sensitivity of -14 nm/N, which is several times higher than what is obtained in conventional fiber Bragg grating force sensors. © 2011 Optical Society of America....

  14. Evaluating the European Defense Force

    Science.gov (United States)

    2002-05-31

    and Haitian Armed Forces ( FADH ) had initiated joint patrolling operations. This caused no small amount of angst among a populace who expected removal...sincerity of US intentions and contributed to demobilizing the FRAPH elements. In one instance a firefight broke out among Marine forces and FADH elements...that helped convince the local populace and 50 later, the rest of the country, that it was not in the US plan to retain and bolster FADH forces.26

  15. The effect of aircraft control forces on pilot performance during instrument landings in a flight simulator.

    Science.gov (United States)

    Hewson, D J; McNair, P J; Marshall, R N

    2001-07-01

    Pilots may have difficulty controlling aircraft at both high and low force levels due to larger variability in force production at these force levels. The aim of this study was to measure the force variability and landing performance of pilots during an instrument landing in a flight simulator. There were 12 pilots who were tested while performing 5 instrument landings in a flight simulator, each of which required different control force inputs. Pilots can produce the least force when pushing the control column to the right, therefore the force levels for the landings were set relative to each pilot's maximum aileron-right force. The force levels for the landings were 90%, 60%, and 30% of maximal aileron-right force, normal force, and 25% of normal force. Variables recorded included electromyographic activity (EMG), aircraft control forces, aircraft attitude, perceived exertion and deviation from glide slope and heading. Multivariate analysis of variance was used to test for differences between landings. Pilots were least accurate in landing performance during the landing at 90% of maximal force (p < 0.05). There was also a trend toward decreased landing performance during the landing at 25% of normal force. Pilots were more variable in force production during the landings at 60% and 90% of maximal force (p < 0.05). Pilots are less accurate at performing instrument landings when control forces are high due to the increased variability of force production. The increase in variability at high force levels is most likely associated with motor unit recruitment, rather than rate coding. Aircraft designers need to consider the reduction in pilot performance at high force levels, as well as pilot strength limits when specifying new standards.

  16. Coaxial Atomic Force Microscope Tweezers

    CERN Document Server

    Brown, K A; Westervelt, R M

    2010-01-01

    We demonstrate coaxial atomic force microscope (AFM) tweezers that can trap and place small objects using dielectrophoresis (DEP). An attractive force is generated at the tip of a coaxial AFM probe by applying a radio frequency voltage between the center conductor and a grounded shield; the origin of the force is found to be DEP by measuring the pull-off force vs. applied voltage. We show that the coaxial AFM tweezers (CAT) can perform three dimensional assembly by picking up a specified silica microsphere, imaging with the microsphere at the end of the tip, and placing it at a target destination.

  17. Magnetic Resonance Force Microscopy System

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

  18. Wind Forces on Container Ships

    DEFF Research Database (Denmark)

    Andersen, Ingrid Marie Vincent

    2012-01-01

    An investigation of the wind forces acting on a 9,000+ TEU container ship has been carried out through a series of wind tunnel tests. It was investigated how the wind forces depend on the container configuration on the deck using a 1:450 scale model and a series of appropriate container...... are presented as nondimensional coefficients. It is concluded, that the measured forces and moment depend on the container configuration on deck, and the results may provide a general idea of how the magnitude of the wind forces is affected by a given container stacking configuration on a similar container ship....

  19. Forces of nature

    CERN Document Server

    AUTHOR|(CDS)2072602

    2016-01-01

    A breathtaking and beautiful exploration of our planet. This groundbreaking book, which accompanies the new BBC1 TV series, provides the deepest answers to the simplest questions. 'Why is the sky blue?' 'Why is the Earth round?' 'Why is every snowflake unique?' To answer these and many other questions, Professor Brian Cox will reveal some of the most extraordinary phenomena and events on Earth and in the Universe and beyond. From the immensity of Earth's globe to all the world's myriad snowflakes, the forces of nature shape everything we see. Pushed to extremes, the results are astonishing. From the realm of auroras to the heart of our planet, the ingredients that make everything on Earth connect each one of us in an eternal cycle of life. Brian will reveal why Earth is the most colourful world we know, exploring the white light of the sun as it travels through the darkness of space until it hits Earth's atmosphere where it begins a new journey, splitting into a rainbow of colours. From the great plains of th...

  20. Tunneling magnetic force microscopy

    Science.gov (United States)

    Burke, Edward R.; Gomez, Romel D.; Adly, Amr A.; Mayergoyz, Isaak D.

    1993-01-01

    We have developed a powerful new tool for studying the magnetic patterns on magnetic recording media. This was accomplished by modifying a conventional scanning tunneling microscope. The fine-wire probe that is used to image surface topography was replaced with a flexible magnetic probe. Images obtained with these probes reveal both the surface topography and the magnetic structure. We have made a thorough theoretical analysis of the interaction between the probe and the magnetic fields emanating from a typical recorded surface. Quantitative data about the constituent magnetic fields can then be obtained. We have employed these techniques in studies of two of the most important issues of magnetic record: data overwrite and maximizing data-density. These studies have shown: (1) overwritten data can be retrieved under certain conditions; and (2) improvements in data-density will require new magnetic materials. In the course of these studies we have developed new techniques to analyze magnetic fields of recorded media. These studies are both theoretical and experimental and combined with the use of our magnetic force scanning tunneling microscope should lead to further breakthroughs in the field of magnetic recording.

  1. External Force Estimation for Teleoperation Based on Proprioceptive Sensors

    Directory of Open Access Journals (Sweden)

    Enrique del Sol

    2014-03-01

    Full Text Available This paper establishes an approach to external force estimation for telerobotic control in radioactive environments by the use of an identified manipulator model and pressure sensors, without employing a force/torque sensor. The advantages of - and need for - force feedback have been well-established in the field of telerobotics, where electrical and back-drivable manipulators have traditionally been used. This research proposes a methodology employing hydraulic robots for telerobotics tasks based on a model identification scheme. Comparative results of a force sensor and the proposed approach using a hydraulic telemanipulator are presented under different conditions. This approach not only presents a cost effective solution but also a methodology for force estimation in radioactive environments, where the dose rates limit the use of electronic devices such as sensing equipment.

  2. Stability of sliding frictional surfaces with varying normal force

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, P.E.; Bapna, D. (Boston Univ., MA (United States))

    1994-04-01

    This paper presents the stability analysis of a single degree-of-freedom elastic system following a rate- and state-dependent friction law. Normal force is assumed to depend on the displacement, velocity, and acceleration of the sliding interface. The history dependence of friction on normal force is included in the analysis. It is shown that to achieve steady sliding, system stiffness must exceed a critical value which depends on the expression for normal force. A system in which normal force depends on spring displacement is analyzed in detail. These results indicate that the functional dependence of normal force on system state can have a significant effect on the stability of low-velocity motion. 15 refs.

  3. Measuring Forces between Oxide Surfaces Using the Atomic Force Microscope

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

    The interactions between colloidal particles play a major role in processing of ceramics, especially in casting processes. With the Atomic Force Microscope (AFM) it is possible to measure the inter-action force between a small oxide particle (a few micron) and a surface as function of surface sep...

  4. Measuring Forces between Oxide Surfaces Using the Atomic Force Microscope

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

    The interactions between colloidal particles play a major role in processing of ceramics, especially in casting processes. With the Atomic Force Microscope (AFM) it is possible to measure the inter-action force between a small oxide particle (a few micron) and a surface as function of surface...

  5. Surface forces studied with colloidal probe atomic force microscopy

    NARCIS (Netherlands)

    Giesbers, M.

    2001-01-01

    Forces between surfaces are a determining factor for the performance of natural as well as synthetic colloidal systems, and play a crucial role in industrial production processes. Measuring these forces is a scientific and experimental challenge and over the years several techniques have been develo

  6. Surface forces studied with colloidal probe atomic force microscopy

    NARCIS (Netherlands)

    Giesbers, M.

    2001-01-01

    Forces between surfaces are a determining factor for the performance of natural as well as synthetic colloidal systems, and play a crucial role in industrial production processes. Measuring these forces is a scientific and experimental challenge and over the years several techniques have

  7. Bacterial adhesion force quantification by fluidic force microscopy

    Science.gov (United States)

    Potthoff, Eva; Ossola, Dario; Zambelli, Tomaso; Vorholt, Julia A.

    2015-02-01

    Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many cells. The contact time and setpoint dependence of the adhesion forces of E. coli and Streptococcus pyogenes, as well as the sequential detachment of bacteria out of a chain, are shown, revealing distinct force patterns in the detachment curves. This study demonstrates the potential of the FluidFM technology for quantitative bacterial adhesion measurements of cell-substrate and cell-cell interactions that are relevant in biofilms and infection biology.Quantification of detachment forces between bacteria and substrates facilitates the understanding of the bacterial adhesion process that affects cell physiology and survival. Here, we present a method that allows for serial, single bacterial cell force spectroscopy by combining the force control of atomic force microscopy with microfluidics. Reversible bacterial cell immobilization under physiological conditions on the pyramidal tip of a microchanneled cantilever is achieved by underpressure. Using the fluidic force microscopy technology (FluidFM), we achieve immobilization forces greater than those of state-of-the-art cell-cantilever binding as demonstrated by the detachment of Escherichia coli from polydopamine with recorded forces between 4 and 8 nN for many

  8. Role of attractive forces in tapping tip force microscopy

    DEFF Research Database (Denmark)

    Kyhle, Anders; Sørensen, Alexis Hammer; Bohr, Jakob

    1997-01-01

    We present experimental and numerical results demonstrating the drastic influence of attractive forces on the behaviour of the atomic force microscope when operated in the resonant tapping tip mode in an ambient environment. It is often assumed that tapping is related to repulsive interaction....... In contrast, we find that in general the attractive forces are the most dominant interaction in this mode of operation. We show that attractive forces in combination with the repulsive elastic type of forces cause points of instability in the parameter space constituted by: the cantilever swing amplitude......, the frequency bias point, and the distance between the fixed end of the cantilever and the sample. These points of instability can result in disturbances during image acquisition on hard elastic surfaces. ©1997 American Institute of Physics....

  9. Population and labour force growth and patterns in ASEAN countries.

    Science.gov (United States)

    Saw, S

    1988-01-01

    "The paper shows that the diverse labor dimensions prevailing in the ASEAN region can be attributed to changes in the structure of the society and economy in the course of recent economic development. It observes the considerable variety in the growth of the population and its effect on the labor force in the ASEAN region.... The paper details the similarity and diversity in the level and type of labor force participation rates. A common feature shared by ASEAN countries is a general pattern in the age-specific participation rate of men. In contrast, the women, aside from participating in the labor force at a much lower level than men at almost all ages, display diverse patterns of participation over the working age range. Lastly, the distribution of the labor force according to major industrial sectors in the six ASEAN countries is presented...."

  10. In Vivo Force Decay of Niti Closed Coil Springs

    Science.gov (United States)

    Cox, Crystal; Nguyen, Tung; Koroluk, Lorne; Ko, Ching-Chang

    2014-01-01

    Introduction Nickel-titanium (NiTi) closed coil springs are purported to deliver constant forces over extended ranges of activation and working times. In vivo studies supporting this claim are limited. The objective of this study is to evaluate changes in force decay properties of NiTi closed coil springs after clinical use. Methods Pseudoelastic force-deflection curves for 30 NiTi coil springs (used intra-orally) and 15 matched laboratory control springs (simulated intra-oral conditions - artificial saliva, 37°C) were tested pre- and post-retrieval via Dynamic Mechanical Analysis (DMA) and the Instron machine, respectively, to evaluate amount of force loss and hysteresis change following 4, 8, or 12 weeks of working time (n=10 per group). Effect of the oral environment and clinical use on force properties were evaluated by comparing in vivo and in vitro data. Results The springs studied showed a statistically significant decrease in force (~12%) following 4 weeks of clinical use (p<0.01), with a further significant decrease (~7%) from 4–8 weeks (p=0.03) and force levels appearing to remain steady thereafter. Clinical space closure at an average rate of 0.91mm per month was still observed despite this decrease in force. In vivo and in vitro force loss data were not statistically different. Conclusions NiTi closed coil springs do not deliver constant forces when used intra-orally, but they still allow for space closure rates of ~1mm/month. PMID:24703289

  11. Determinants of Female Labor Force Participation

    Directory of Open Access Journals (Sweden)

    Dr. Adiqa Kausar Kiani

    2009-12-01

    Full Text Available There are many factors related to female entering the labor market. For example, household income, household expenditure, education and status of the head of the household (male/ female. The degree of correlation between each variable and female labor force participation rate varies throughout the country. This study focused on the factors due to which women enter in labor market. Tobit model is used for this analysis. It is concluded that education and household expenditures have positive but insignificant impact on the female LF, whereas household income and head of the household has negative impact on FLF. It is suggested that in order to improve the working condition of female labor force government should take necessary action, for example women education etc.

  12. The application of force-sensing resistor sensors for measuring forces developed by the human hand.

    Science.gov (United States)

    Nikonovas, A; Harrison, A J L; Hoult, S; Sammut, D

    2004-01-01

    Most attempts to measure forces developed by the human hand have been implemented by placing force sensors on the object of interaction. Other researchers have placed sensors just on the subject's fingertips. In this paper, a system is described that measures forces over the entire hand using thin-film sensors and associated electronics. This system was developed by the authors and is able to obtain force readings from up to 60 thin-film sensors at rates of up to 400 samples/s per sensor. The sensors can be placed anywhere on the palm and/or fingers of the hand. The sensor readings, together with a video stream containing information about hand posture, are logged into a portable computer using a multiplexer, analogue-to-digital converter and software developed for the purpose. The system has been successfully used to measure forces involved in a range of everyday tasks such as driving a vehicle, lifting saucepans and hitting a golf ball. In the latter case, results are compared with those from an instrumented golf club. Future applications include the assessment of hand strength following disease, trauma or surgery, and to enable quantitative ergonomic investigations.

  13. Challenges in ethics, safety, best practices, and oversight regarding HIT vendors, their customers, and patients: a report of an AMIA special task force

    Science.gov (United States)

    Berner, Eta S; Dente, Mark A; Kaplan, Bonnie; Koppel, Ross; Rucker, Donald; Sands, Daniel Z; Winkelstein, Peter

    2010-01-01

    The current commercial health information technology (HIT) arena encompasses a number of competing firms that provide electronic health applications to hospitals, clinical practices, and other healthcare-related entities. Such applications collect, store, and analyze patient information. Some vendors incorporate contract language whereby purchasers of HIT systems, such as hospitals and clinics, must indemnify vendors for malpractice or personal injury claims, even if those events are not caused or fostered by the purchasers. Some vendors require contract clauses that force HIT system purchasers to adopt vendor-defined policies that prevent the disclosure of errors, bugs, design flaws, and other HIT-software-related hazards. To address this issue, the AMIA Board of Directors appointed a Task Force to provide an analysis and insights. Task Force findings and recommendations include: patient safety should trump all other values; corporate concerns about liability and intellectual property ownership may be valid but should not over-ride all other considerations; transparency and a commitment to patient safety should govern vendor contracts; institutions are duty-bound to provide ethics education to purchasers and users, and should commit publicly to standards of corporate conduct; and vendors, system purchasers, and users should encourage and assist in each others' efforts to adopt best practices. Finally, the HIT community should re-examine whether and how regulation of electronic health applications could foster improved care, public health, and patient safety. PMID:21075789

  14. On binary pulsars and the force of gravity

    CERN Document Server

    Palle, D

    2002-01-01

    We reanalyze a binary pulsar system and show that the orbital period change rate can be completely understood as a curvature backreaction process. Appreciating a detailed theoretical and observational study of relativistic binary pulsar systems, especially the system of Hulse and Taylor, we conclude that general relativity and astrophysical observations rule out the existence of gravitational radiation. Thus, the force of gravity is not a local gauge force.

  15. Factors influencing power hand tool fastening accuracy and reaction forces.

    Science.gov (United States)

    Radwin, Robert G; Chourasia, Amrish O; Howery, Robert S; Fronczak, Frank J; Yen, Thomas Y; Subedi, Yashpal; Sesto, Mary E

    2014-06-01

    A laboratory study investigated the relationship between power hand tool and task-related factors affecting threaded fastener torque accuracy and associated handle reaction force. We previously developed a biodynamic model to predict handle reaction forces. We hypothesized that torque accuracy was related to the same factors that affect operator capacity to react against impulsive tool forces, as predicted by the model. The independent variables included tool (pistol grip on a vertical surface, right angle on a horizontal surface), fastener torque rate (hard, soft), horizontal distance (30 cm and 60 cm), and vertical distance (80 cm, 110 cm, and 140 cm). Ten participants (five male and five female) fastened 12 similar bolts for each experimental condition. Average torque error (audited - target torque) was affected by fastener torque rate and operator position. Torque error decreased 33% for soft torque rates, whereas handle forces greatly increased (170%). Torque error also decreased for the far horizontal distance 7% to 14%, when vertical distance was in the middle or high, but handle force decreased slightly 3% to 5%. The evidence suggests that although both tool and task factors affect fastening accuracy, they each influence handle reaction forces differently. We conclude that these differences are attributed to different parameters each factor influences affecting the dynamics of threaded faster tool operation. Fastener torque rate affects the tool dynamics, whereas posture affects the spring-mass-damping biodynamic properties of the human operator. The prediction of handle reaction force using an operator biodynamic model may be useful for codifying complex and unobvious relationships between tool and task factors for minimizing torque error while controlling handle force.

  16. Solvent effects on the AIBN forced degradation of cumene: Implications for forced degradation practices.

    Science.gov (United States)

    Nelson, Eric D; Thompson, Gina M; Yao, Ye; Flanagan, Holly M; Harmon, Paul A

    2009-03-01

    Solvent effects on the AIBN and ACVA forced degradation of cumene are explored. The degradant formation rates of the three cumene oxidative degradants, cumene hydroperoxide, acetophenone, and 2-phenyl-2-propanol are reported. The relative abundance and ratios of these three degradants provide insight into the fate of the peroxy radical oxidants generated by the forced stress system, and suggest that alkoxy radicals are actually a significant source of the observed reactivity. The presence of even 1% methanol in the forced stress solvent significantly quenches this alkoxy radical reactivity, dramatically reducing the overall degradation rate and leaving cumene hydroperoxide as the major product of the oxidation reaction. The origin of this significant solvent effect on the oxidation product distribution is shown to be related to the preferential H-atom abstraction from methanol and its trace impurities by any alkoxy radicals present in the reaction solution. The implications for these observations are explored with the intent of producing more predictive oxidative forced stress experiments.

  17. Atomic Force Microscope Operation

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation (large file) This animation is a scientific illustration of the operation of NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA. The AFM is used to image the smallest Martian particles using a very sharp tip at the end of one of eight beams. The beam of the AFM is set into vibration and brought up to the surface of a micromachined silicon substrate. The substrate has etched in it a series of pits, 5 micrometers deep, designed to hold the Martian dust particles. The microscope then maps the shape of particles in three dimensions by scanning them with the tip. At the end of the animation is a 3D representation of the AFM image of a particle that was part of a sample informally called 'Sorceress.' The sample was delivered to the AFM on the 38th Martian day, or sol, of the mission (July 2, 2008). The image shows four round pits, only 5 microns in depth, that were micromachined into the silicon substrate. A Martian particle only one micrometer, or one millionth of a meter, across is held in the upper left pit. The rounded particle shown at the highest magnification ever seen from another world is a particle of the dust that cloaks Mars. Such dust particles color the Martian sky pink, feed storms that regularly envelop the planet and produce Mars' distinctive red soil. The AFM was developed by a Swiss-led consortium, with Imperial College London producing the silicon substrate that holds sampled particles. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  18. Anthropogenic forcing dominates sea level rise since 1850

    DEFF Research Database (Denmark)

    Jevrejeva, Svetlana; Grinsted, Aslak; Moore, John

    2009-01-01

    The rate of sea level rise and its causes are topics of active debate. Here we use a delayed response statistical model to attribute the past 1000 years of sea level variability to various natural (volcanic and solar radiative) and anthropogenic (greenhouse gases and aerosols) forcings. We show...... that until 1800 the main drivers of sea level change are volcanic and solar radiative forcings. For the past 200 years sea level rise is mostly associated with anthropogenic factors. Only 4 ± 1.5 cm (25% of total sea level rise) during the 20th century is attributed to natural forcings, the remaining 14 ± 1...

  19. Casimir switch: steering optical transparency with vacuum forces

    CERN Document Server

    Liu, X -f; Jing, H

    2016-01-01

    The Casimir force, originating from vacuum zero-point energy, is one of the most intriguing purely quantum effects. It has attracted renewed interests in current field of nanomechanics, due to the rapid size decrease of on-chip devices. Here we study the optomechanically-induced transparency (OMIT) with a tunable Casimir force. We find that the optical output rate can be significantly altered by the vacuum force, even terminated and then restored, indicating a highly-controlled optical switch. Our result addresses the possibility of designing exotic optical nano-devices by harnessing the power of vacuum.

  20. How Does Force Affect Motion?

    Science.gov (United States)

    Darling, Gerald

    2012-01-01

    Whether playing soccer at recess, walking to lunch, or sitting at their desk, children encounter forces every moment of their lives. The connection between force and motion is absolutely amazing to children, so anyone working with them better be prepared for the battery of tough questions they ask: "What made the ball move that way? Why does a…

  1. Radiative screening of fifth forces

    CERN Document Server

    Burrage, Clare; Millington, Peter

    2016-01-01

    We describe a symmetron model in which the screening of fifth forces arises at the one-loop level through the Coleman-Weinberg mechanism of spontaneous symmetry breaking. We show that such a theory can avoid current constraints on the existence of fifth forces, but still has the potential to give rise to observable deviations from general relativity.

  2. Multiphase forces on bend structures

    NARCIS (Netherlands)

    Nennie, E.D.; Belfroid, S.P.C.

    2016-01-01

    Piping structures are generally subjected to high dynamic loading due to multiphase forces. In particular subsea structures are very vulnerable as large flexibility is required to cope for instance with thermal stresses. The forces due to multiphase flow are characterized by a broadband spectrum wit

  3. Force approach to radiation reaction

    Energy Technology Data Exchange (ETDEWEB)

    López, Gustavo V., E-mail: gulopez@udgserv.cencar.udg.mx

    2016-02-15

    The difficulty of the usual approach to deal with the radiation reaction is pointed out, and under the condition that the radiation force must be a function of the external force and is zero whenever the external force be zero, a new and straightforward approach to radiation reaction force and damping is proposed. Starting from the Larmor formula for the power radiated by an accelerated charged particle, written in terms of the applied force instead of the acceleration, an expression for the radiation force is established in general, and applied to the examples for the linear and circular motion of a charged particle. This expression is quadratic in the magnitude of the applied force, inversely proportional to the speed of the charged particle, and directed opposite to the velocity vector. This force approach may contribute to the solution of the very old problem of incorporating the radiation reaction to the motion of the charged particles, and future experiments may tell us whether or not this approach point is in the right direction.

  4. Force approach to radiation reaction

    Science.gov (United States)

    López, Gustavo V.

    2016-02-01

    The difficulty of the usual approach to deal with the radiation reaction is pointed out, and under the condition that the radiation force must be a function of the external force and is zero whenever the external force be zero, a new and straightforward approach to radiation reaction force and damping is proposed. Starting from the Larmor formula for the power radiated by an accelerated charged particle, written in terms of the applied force instead of the acceleration, an expression for the radiation force is established in general, and applied to the examples for the linear and circular motion of a charged particle. This expression is quadratic in the magnitude of the applied force, inversely proportional to the speed of the charged particle, and directed opposite to the velocity vector. This force approach may contribute to the solution of the very old problem of incorporating the radiation reaction to the motion of the charged particles, and future experiments may tell us whether or not this approach point is in the right direction.

  5. Force.com enterprise architecture

    CERN Document Server

    Fawcett, Andrew

    2014-01-01

    This book is for advanced Force.com developers and architects who need to understand the Salesforce platform from the perspective of enterprise-level requirements. You should have an existing understanding of Apex and Visualforce. Those familiar with other enterprise software ecosystems will also find this book ideal as they adopt Force.com.

  6. Seven Important Labor Force Trends.

    Science.gov (United States)

    Bailey, John A.

    1982-01-01

    Presents statistics on the changing human resources mix in the labor force, which vocational counselors should be aware of. Trends include higher percentages of women working, and older men and married men leaving the work force. One result is an increasing number of persons are able to retire earlier. (JAC)

  7. Multiphase forces on bend structures

    NARCIS (Netherlands)

    Nennie, E.D.; Belfroid, S.P.C.

    2016-01-01

    Piping structures are generally subjected to high dynamic loading due to multiphase forces. In particular subsea structures are very vulnerable as large flexibility is required to cope for instance with thermal stresses. The forces due to multiphase flow are characterized by a broadband spectrum wit

  8. Response of Brownian Fluctuations to External Forces

    Science.gov (United States)

    Laub, Jeffrey William

    Millikan's law of particle fall is an empirical result which shows the dependence of particle fall rate in a gas on particle radius and host gas density. The size of submicron particles in gases has long been determined by Millikan's law. The dominant factor is Stokes' law with a correction added to account for the physics of slip. However, it was recently shown by Kim and Fedele that Brownian fluctuations affect the fall rate while showing no anomalies in the density dependence of the rms displacement. The effect was an enhancement of the fall rate of small particles as the density of the host gas is increased. This enhancement showed a size dependence in the form of a smooth transition from the one of decreasing fall rate with increasing density for large particles (~0.4 μm radius) to another of increasing fall rate with increasing gas density for small particles ( ~0.15mum radius). The magnitude of the anomaly is determined by how the rms Brownian velocity compares with its fall rate. In an effort to understand the effect of Brownian fluctuations coupling with gravity, a new experiment has been carried out where an AC field was applied to force particles to fluctuate more in the vertical direction on one hand and where a constant DC field was applied to change the effective force of gravity on the other. These fields were applied to a charged oil drop in the 0.2 to 0.3 μm radius range falling in a nitrogen environment. Displacements over a 4 second time interval were repeatedly measured in both the vertical and horizontal directions. The original experimental apparatus was used with some modifications. The modifications included computer automation of particle control and data taking to allow for longer use of the same particle, up to 120 hours, and to facilitate application of the additional fields. The objective was to make large particles appear to be smaller via forced oscillations and make them fall faster or slower via the DC bias to effect the change in

  9. Single-cell force spectroscopy.

    Science.gov (United States)

    Helenius, Jonne; Heisenberg, Carl-Philipp; Gaub, Hermann E; Muller, Daniel J

    2008-06-01

    The controlled adhesion of cells to each other and to the extracellular matrix is crucial for tissue development and maintenance. Numerous assays have been developed to quantify cell adhesion. Among these, the use of atomic force microscopy (AFM) for single-cell force spectroscopy (SCFS) has recently been established. This assay permits the adhesion of living cells to be studied in near-physiological conditions. This implementation of AFM allows unrivaled spatial and temporal control of cells, as well as highly quantitative force actuation and force measurement that is sufficiently sensitive to characterize the interaction of single molecules. Therefore, not only overall cell adhesion but also the properties of single adhesion-receptor-ligand interactions can be studied. Here we describe current implementations and applications of SCFS, as well as potential pitfalls, and outline how developments will provide insight into the forces, energetics and kinetics of cell-adhesion processes.

  10. Handbook of Molecular Force Spectroscopy

    CERN Document Server

    Noy, Aleksandr

    2008-01-01

    "...Noy's Handbook of Molecular Force Spectroscopy is both a timely and useful summary of fundamental aspects of molecular force spectroscopy, and I believe it would make a worthwhile addition to any good scientific library. New research groups that are entering this field would be well advisedto study this handbook in detail before venturing into the exciting and challenging world of molecular force spectroscopy." Matthew F. Paige, University of Saskatchewan, Journal of the American Chemical Society Modern materials science and biophysics are increasingly focused on studying and controlling intermolecular interactions on the single-molecule level. Molecular force spectroscopy was developed in the past decade as the result of several unprecedented advances in the capabilities of modern scientific instrumentation, and defines a number of techniques that use mechanical force measurements to study interactions between single molecules and molecular assemblies in chemical and biological systems. Examples of these...

  11. Entropic forces in Brownian motion

    CERN Document Server

    Roos, Nico

    2013-01-01

    The interest in the concept of entropic forces has risen considerably since E. Verlinde proposed to interpret the force in Newton s second law and Gravity as entropic forces. Brownian motion, the motion of a small particle (pollen) driven by random impulses from the surrounding molecules, may be the first example of a stochastic process in which such forces are expected to emerge. In this note it is shown that at least two types of entropic motion can be identified in the case of 3D Brownian motion (or random walk). This yields simple derivations of known results of Brownian motion, Hook s law and, applying an external (nonradial) force, Curie s law and the Langevin-Debye equation.

  12. Force-velocity measurements of a few growing actin filaments.

    Directory of Open Access Journals (Sweden)

    Coraline Brangbour

    2011-04-01

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

  13. Force-Velocity Measurements of a Few Growing Actin Filaments

    Science.gov (United States)

    Brangbour, Coraline; du Roure, Olivia; Helfer, Emmanuèle; Démoulin, Damien; Mazurier, Alexis; Fermigier, Marc; Carlier, Marie-France; Bibette, Jérôme; Baudry, Jean

    2011-01-01

    The polymerization of actin in filaments generates forces that play a pivotal role in many cellular processes. We introduce a novel technique to determine the force-velocity relation when a few independent anchored filaments grow between magnetic colloidal particles. When a magnetic field is applied, the colloidal particles assemble into chains under controlled loading or spacing. As the filaments elongate, the beads separate, allowing the force-velocity curve to be precisely measured. In the widely accepted Brownian ratchet model, the transduced force is associated with the slowing down of the on-rate polymerization. Unexpectedly, in our experiments, filaments are shown to grow at the same rate as when they are free in solution. However, as they elongate, filaments are more confined in the interspace between beads. Higher repulsive forces result from this higher confinement, which is associated with a lower entropy. In this mechanism, the production of force is not controlled by the polymerization rate, but is a consequence of the restriction of filaments' orientational fluctuations at their attachment point. PMID:21541364

  14. Direct measurement of interaction forces between a platinum dichloride complex and DNA molecules.

    Science.gov (United States)

    Muramatsu, Hiroshi; Shimada, Shogo; Okada, Tomoko

    2017-06-29

    The interaction forces between a platinum dichloride complex and DNA molecules have been studied using atomic force microscopy (AFM). The platinum dichloride complex, di-dimethylsulfoxide-dichloroplatinum (II) (Pt(DMSO)2Cl2), was immobilized on an AFM probe by coordinating the platinum to two amino groups to form a complex similar to Pt(en)Cl2, which is structurally similar to cisplatin. The retraction forces were measured between the platinum complex and DNA molecules immobilized on mica plates using force curve measurements. The histogram of the retraction force for λ-DNA showed several peaks; the unit retraction force was estimated to be 130 pN for a pulling rate of 60 nm/s. The retraction forces were also measured separately for four single-base DNA oligomers (adenine, guanine, thymine, and cytosine). Retraction forces were frequently observed in the force curves for the DNA oligomers of guanine and adenine. For the guanine DNA oligomer, the most frequent retraction force was slightly lower than but very similar to the retraction force for λ-DNA. A higher retraction force was obtained for the adenine DNA oligomer than for the guanine oligomer. This result is consistent with a higher retraction activation energy of adenine with the Pt complex being than that of guanine because the kinetic rate constant for retraction correlates to exp(FΔx - ΔE) where ΔE is an activation energy, F is an applied force, and Δx is a displacement of distance.

  15. Eccentric Inspirals with Self-Force and Spin-Force

    Science.gov (United States)

    Evans, Charles; Osburn, Thomas; Warburton, Niels

    2017-01-01

    Eccentric inspirals of a small mass about a more massive Schwarzschild black hole (EMRIs or IMRIs) are calculated using the gravitational self-force and the Mathisson-Papapetrou spin-force. These calculations include all dissipative and conservative effects that are first order in the mass ratio. We compute systems with initial eccentricities as high as e = 0.8, initial separations as large as 50 M, and arbitrary spin orientations. Including the spin-force causes the orbital plane to precess. Inspirals are calculated using an osculating-orbits scheme that is driven by self-force data from a hybrid self-force code and time-domain spin-force calculations. The hybrid approach uses both self-force data from a Lorenz gauge code and highly accurate flux data from a Regge-Wheeler-Zerilli code, allowing the hybrid model to track orbital phase of inspirals to within 0.1 radians or better over hundreds or thousands of orbits. NSF PHY15-06182.

  16. Annual US Air Force Sexually Transmitted Disease (STD) Report, 1995.

    Science.gov (United States)

    1996-05-01

    This report evaluates the 1995 US Air Force (USAF) Sexually Transmitted Diseases ( STD ) Prevention and Control Program. The report analyzes data from...88 medical treatment facilities worldwide and compares 1995 data with that from 1992-94. The 1995 USAF active duty total STD incidence rate was 7.64...cases per 1,000 personnel. This rate represents a 18.9% decline from the 1994 reported STD incidence rate of 9.41 per 1,000 personnel. Among active

  17. Forced Sequence Sequential Decoding

    DEFF Research Database (Denmark)

    Jensen, Ole Riis

    In this thesis we describe a new concatenated decoding scheme based on iterations between an inner sequentially decoded convolutional code of rate R=1/4 and memory M=23, and block interleaved outer Reed-Solomon codes with non-uniform profile. With this scheme decoding with good performance is pos...... of computational overflow. Analytical results for the probability that the first Reed-Solomon word is decoded after C computations are presented. This is supported by simulation results that are also extended to other parameters....

  18. Bipolar electrosurgical vessel-sealing device with compressive force monitoring.

    Science.gov (United States)

    Chen, Roland K; Chastagner, Matthew W; Geiger, James D; Shih, Albert J

    2014-06-01

    Bipolar electrosurgical vessel sealing is commonly used in surgery to perform hemostasis. The electrode compressive force is demonstrably an important factor affecting the vessel seal burst pressure, an index of the seal quality. Using a piezoresistive force sensor attached to the handle of a laparoscopic surgical device, applied handle force was measured and used to predict the electrosurgical vessel compressive force and the pressure at the electrode. The sensor enables the monitoring of vessel compressive force during surgery. Four levels of compressive force were applied to seal three types of porcine vessels (carotid artery, femoral artery, and jugular vein). The burst pressure of the vessel seal was tested to evaluate the seal quality. Compressive pressure was found to be a statistically significant factor affecting burst pressure for femoral arteries and jugular veins. Vessels sealed with low compressive pressure (<300 kPa) have a higher failure rate (burst pressure<100 mm Hg) than vessels sealed with high compressive pressure. An adequate compressive force is required to generate the compressive pressure needed to form a seal with high burst pressure. A laparoscopic surgical device with compressive force monitoring capability can help ensure adequate compressive pressure, vessel burst pressure, and quality of seal.

  19. Compressive force magnitude and intervertebral joint flexion/extension angle influence shear failure force magnitude in the porcine cervical spine.

    Science.gov (United States)

    Howarth, Samuel J; Callaghan, Jack P

    2012-02-02

    Despite the findings that peak anterior shear load is highly correlated with low-back pain reporting, very little research has been conducted to determine how vertebral shear injury potential is influenced. The current study quantified the combined effects of vertebral joint compression and flexion/extension postural deviation from neutral on ultimate shear failure. Ninety-six porcine cervical specimens (48C3-C4, 48C5-C6) were tested. Each specimen was randomly assigned to one of twelve combinations of compressive force (15%, 30%, 45%, or 60% of predicted compressive failure force) and flexion/extension postural deviation (extended, neutral, or flexed). Vertebral joint shear failure was induced by applying posterior shear displacement of the caudal vertebra at a constant rate of 0.15 mm/s. Throughout shear failure tests, vertebral joint kinematics were measured using an optoelectronic camera and a series of infrared light emitting diodes while shear force was measured from load cells rigidly interfaced in series with linear actuators that applied the shear displacement. Measurements of shear stiffness, ultimate force, displacement, and energy stored were made from the force-displacement data. Compressive force and postural deviation demonstrated main effects without a statistically significant interaction for any of the measurements. Shear failure force increased by 11.1% for each 15% increment in compressive force (pflexion (pflexion/extension postural deviation should be equally considered while assessing shear injury potential.

  20. Force modulating dynamic disorder: A physical model of catch-slip bond transitions in receptor-ligand forced dissociation experiments

    Science.gov (United States)

    Liu, Fei; Ou-Yang, Zhong-Can

    2006-11-01

    Recent experiments found that some adhesive receptor-ligand complexes have counterintuitive catch-slip transition behaviors: the mean lifetimes of these complexes first increase (catch) with initial application of a small external force, and then decrease (slip) when the force is beyond some threshold. In this work we suggest that the forced dissociation of these complexes might be a typical rate process with dynamic disorder. The one-dimensional force modulating Agmon-Hopfield model is used to describe the transitions in the single-bond P-selectin glycoprotein ligand 1-P-selectin forced dissociation experiments, which were respectively performed in the constant force [Marshall , Nature (Landon) 423, 190 (2003)] and the ramping force [Evans , Proc. Natl. Acad. Sci. U.S.A 98, 11281 (2004)] modes. We find that, an external force can not only accelerate the bond dissociation, but also modulate the complex from the lower-energy barrier to the higher one; the catch-slip bond transition can arise from a particular energy barrier shape. The agreement between our calculation and the experimental data is satisfactory.

  1. Age estimates and uplift rates for Late Pleistocene marine terraces: Southern Oregon portion of the Cascadia Forearc

    Science.gov (United States)

    Muhs, Daniel R.; Kelsey, Harvey M.; Miller, Gifford H.; Kennedy, George L.; Whelan, Joseph F.; McInelly, Galan W.

    1990-05-01

    Marine terraces are prominent landforms along the southern Oregon coast, which forms part of the forearc region of the Cascadia subduction zone. Interest in the Cascadia subduction zone has increased because recent investigations have suggested that slip along plates at certain types of convergent margins is characteristically accompanied by large earthquakes. In addition, other investigations have suggested that convergent margins can be broadly classified by the magnitude of their uplift rates. With these hypotheses in mind, we generated new uranium series, amino acid, and stable isotope data for southern Oregon marine terrace fossils. These data, along with terrace elevations and two alternative estimates of sea level at the time of terrace formation, allow us to determine terrace ages and uplift rates. Uranium series analysis of fossil coral yields an age of 83±5 ka for the Whisky Run terrace at Coquille Point in Bandon, Oregon. A combination of amino acid and oxygen isotope data suggest ages of about 80 and 105 ka for the lowest two terraces at Cape Blanco. These ages indicate uplift rates of 0.45-1.05 and 0.81-1.49 m/kyr for Coquille Point and Cape Blanco, respectively. Late Quaternary uplift rates of marine terraces yield information about deformation in the overriding plate, but it is unclear if such data vary systematically with convergent margin type. In order to assess the utility of the southern Oregon uplift rates for predicting the behavior of the Cascadia subduction zone, we compared late Quaternary uplift rates derived from terrace data from subduction zones around the world. On the basis of this comparison the southern Oregon rates of vertical deformation are not unusually high or low. Furthermore, late Quaternary uplift rates show little relationship to the type of convergent margin. These observations suggest that local structures may play a large role in uplift rate variability. In addition, while the type of convergent margin may place an

  2. Aberrant Force Processing in Schizophrenia.

    Science.gov (United States)

    Martinelli, Cristina; Rigoli, Francesco; Shergill, Sukhwinder S

    2016-07-06

    Initially considered as mere side effects of antipsychotic medication, there is now evidence that motor and somatosensory disturbances precede the onset of the illness and can be found in drug-naive patients. However, research on the topic is scarce. Here, we were interested in assessing the accuracy of the neural signal in detecting parametric variations of force linked to a voluntary motor act and a received tactile sensation, either self-generated or externally generated. Patients with a diagnosis of schizophrenia and healthy controls underwent functional magnetic resonance imaging while asked to press, or abstain from pressing, a lever in order to match a visual target force. Forces, exerted and received, varied on 10 levels from 0.5 N to 5 N in 0.5 N increments. Healthy participants revealed a positive correlation between force and activity in contralateral primary somatosensory area (S1) when performing a movement as well as when receiving a tactile sensation but only when this was externally, and not self-, generated. Patients showed evidence of altered force signaling in both motor and tactile conditions, as well as increased correlation with force when tactile sensation was self-generated. Findings are interpreted in line with accounts of predictive and sensory integration mechanisms and point toward alterations in the encoding of parametric forces in the motor and somatosensory domain in patients affected by schizophrenia.

  3. Forced thermal cycling of catalytic reactions: experiments and modelling

    DEFF Research Database (Denmark)

    Jensen, Søren; Olsen, Jakob Lind; Thorsteinsson, Sune;

    2007-01-01

    Recent studies of catalytic reactions subjected to fast forced temperature oscillations have revealed a rate enhancement increasing with temperature oscillation frequency. We present detailed studies of the rate enhancement up to frequencies of 2.5 Hz. A maximum in the rate enhancement is observed...... at about 1 Hz. A model for the rate enhancement that includes the surface kinetics and the dynamic partial pressure variations in the reactor is introduced. The model predicts a levelling off of the rate enhancement with frequency at about 1 Hz. The experimentally observed decrease above 1 Hz is explained...... by dynamic thermal limitations of the reactor. (c) 2007 Elsevier B.V. All rights reserved....

  4. Compressed sensing traction force microscopy.

    Science.gov (United States)

    Brask, Jonatan Bohr; Singla-Buxarrais, Guillem; Uroz, Marina; Vincent, Romaric; Trepat, Xavier

    2015-10-01

    Adherent cells exert traction forces on their substrate, and these forces play important roles in biological functions such as mechanosensing, cell differentiation and cancer invasion. The method of choice to assess these active forces is traction force microscopy (TFM). Despite recent advances, TFM remains highly sensitive to measurement noise and exhibits limited spatial resolution. To improve the resolution and noise robustness of TFM, here we adapt techniques from compressed sensing (CS) to the reconstruction of the traction field from the substrate displacement field. CS enables the recovery of sparse signals at higher resolution from lower resolution data. Focal adhesions (FAs) of adherent cells are spatially sparse implying that traction fields are also sparse. Here we show, by simulation and by experiment, that the CS approach enables circumventing the Nyquist-Shannon sampling theorem to faithfully reconstruct the traction field at a higher resolution than that of the displacement field. This allows reaching state-of-the-art resolution using only a medium magnification objective. We also find that CS improves reconstruction quality in the presence of noise. A great scientific advance of the past decade is the recognition that physical forces determine an increasing list of biological processes. Traction force microscopy which measures the forces that cells exert on their surroundings has seen significant recent improvements, however the technique remains sensitive to measurement noise and severely limited in spatial resolution. We exploit the fact that the force fields are sparse to boost the spatial resolution and noise robustness by applying ideas from compressed sensing. The novel method allows high resolution on a larger field of view. This may in turn allow better understanding of the cell forces at the multicellular level, which are known to be important in wound healing and cancer invasion. Copyright © 2015 Acta Materialia Inc. Published by Elsevier

  5. Numerical Ultimate Ruin Probabilities under Interest Force

    Directory of Open Access Journals (Sweden)

    Juma Kasozi

    2005-01-01

    Full Text Available This work addresses the issue of ruin of an insurer whose portfolio is exposed to insurance risk arising from the classical surplus process. Availability of a positive interest rate in the financial world forces the insurer to invest into a risk free asset. We derive a linear Volterra integral equation of the second kind and apply an order four Block-by-block method in conjuction with the Simpson rule to solve the Volterra equation for ultimate ruin. This probability is arrived at by taking a linear combination of some two solutions to the Volterra integral equation. The several numerical examples given show that our results are excellent and reliable.

  6. From Wardens Air Force to Boyds Air Force

    Science.gov (United States)

    2016-04-01

    a twentieth century bureaucracy that celebrates centralized control and it can continue to propagate a manner of thinking that wishes away...command and control paradigm and restructure Air Force intelligence squadrons into multi-intelligence discipline (multi-INT) organizations. 4...To truly be prepared for the uncertainty of future battlefields the Air Force must embrace a new model of ISR command & control and the

  7. Air Force Security Forces Professionalism: Useful Insights for Leaders

    Science.gov (United States)

    2013-03-27

    Enforcement, and Security.66 The division’s intent to improve technical competence in each area by providing a sharper focus was controversial. Some...credential for Security Forces members and provided assurance to Air Force communities that competent professionals were protecting them. Secrest 26...Rand Corp, 2002. Bachman , Jerald G., David R. Segal, Peter Freedman-Doan, and Patrick M. O’Maley. Who Chooses Military Service? Correlates of

  8. Avoiding a Hollow Force: Force Planning with Any Budget

    Science.gov (United States)

    2012-05-30

    1 Cassata, Burns, Dozier, and Baldor , ―U.S. ground forces could be cut by 100,000, Defense Secretary Panetta says‖, Associated Press...spending. Figure 2 8 7 Cassata, Burns, Dozier, and Baldor , op cit. 8 Ibid. 4 Figure 3 (below... Baldor , ―U.S. ground forces could be cut by 100,000, Defense Secretary Panetta says‖, Associated Press, Jan 26 2012. http://www.nola.com/military

  9. Radiometric force in dusty plasmas

    CERN Document Server

    Ignatov, A M

    2000-01-01

    A radiofrequency glow discharge plasma, which is polluted with a certain number of dusty grains, is studied. In addition to various dusty plasma phenomena, several specific colloidal effects should be considered. We focus on radiometric forces, which are caused by inhomogeneous temperature distribution. Aside from thermophoresis, the role of temperature distribution in dusty plasmas is an open question. It is shown that inhomogeneous heating of the grain by ion flows results in a new photophoresis like force, which is specific for dusty discharges. This radiometric force can be observable under conditions of recent microgravity experiments.

  10. Radiohumeral stability to forced translation

    DEFF Research Database (Denmark)

    Jensen, Steen Lund; Olsen, Bo Sanderhoff; Seki, Atsuhito

    2002-01-01

    Radiohumeral stability to forced translation was experimentally analyzed in 8 osteocartilaginous joint preparations. The joints were dislocated in 8 centrifugal directions at 12 different combinations of joint flexion and rotation while a constant joint compression force of 23 N was applied....... Stability was measured as the maximum resistance to translation. On average, the specimens could resist a transverse force of 16.4 N (range, 13.0-19.1 N). Stability was greater in some directions than in others. Rotating the joint changed the direction at which stability was greatest, whereas joint flexion...

  11. Influence of maglev force relaxation on the forces of bulk HTSC subjected to different lateral displacements above the NdFeB guideway

    Energy Technology Data Exchange (ETDEWEB)

    Qin Yujie, E-mail: qyjswjtu@vip.sohu.co [Department of Computer and Information Engineering, Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China); Hou Xiaojing [Department of Computer and Information Engineering, Luoyang Institute of Science and Technology, Luoyang, Henan 471023 (China)

    2011-02-15

    Research highlights: {yields} The relaxation properties of maglev forces have been investigated simultaneously. {yields} Influence of relaxation on forces of HTSC subjected to different LDs above PMG is different. {yields} The influence is explained based on motion of flux lines, re/demagnetization of HTSC during LD. {yields} The work provide a scientific analysis for the practical application of the bulk HTSC. - Abstract: This paper studied the influence of maglev force relaxation on the force (both levitation and guidance forces) of bulk high-temperature superconductor (HTSC) subjected to different lateral displacements above a NdFeB guideway. Firstly, the maglev forces relaxation property of bulk HTSC above the permanent-magnet guideway (PMG) was studied experimentally, then the levitation and guidance forces were measured by SCML-2 measurement system synchronously at different lateral displacements, some times later(after relaxation), the forces were measured again as the same way. Compared to the two measured results, it was found that the change of the levitation force was larger compared to the case without relaxation, while the change of the guidance force was smaller. In addition, the rate of change of levitation force and guidance force was different for different maximum lateral displacements. This work provided a scientific analysis for the practical application of the bulk HTS.

  12. Which forcing data errors matter most when modeling seasonal snowpacks?

    Science.gov (United States)

    Raleigh, M. S.; Lundquist, J. D.; Clark, M. P.

    2014-12-01

    High quality forcing data are critical when modeling seasonal snowpacks and snowmelt, but their quality is often compromised due to measurement errors or deficiencies in gridded data products (e.g., spatio-temporal interpolation, empirical parameterizations, or numerical weather model outputs). To assess the relative impact of errors in different meteorological forcings, many studies have conducted sensitivity analyses where errors (e.g., bias) are imposed on one forcing at a time and changes in model output are compared. Although straightforward, this approach only considers simplistic error structures and cannot quantify interactions in different meteorological forcing errors (i.e., it assumes a linear system). Here we employ the Sobol' method of global sensitivity analysis, which allows us to test how co-existing errors in six meteorological forcings (i.e., air temperature, precipitation, wind speed, humidity, incoming shortwave and longwave radiation) impact specific modeled snow variables (i.e., peak snow water equivalent, snowmelt rates, and snow disappearance timing). Using the Sobol' framework across a large number of realizations (>100000 simulations annually at each site), we test how (1) the type (e.g., bias vs. random errors), (2) distribution (e.g., uniform vs. normal), and (3) magnitude (e.g., instrument uncertainty vs. field uncertainty) of forcing errors impact key outputs from a physically based snow model (the Utah Energy Balance). We also assess the role of climate by conducting the analysis at sites in maritime, intermountain, continental, and tundra snow zones. For all outputs considered, results show that (1) biases in forcing data are more important than random errors, (2) the choice of error distribution can enhance the importance of specific forcings, and (3) the level of uncertainty considered dictates the relative importance of forcings. While the relative importance of forcings varied with snow variable and climate, the results broadly

  13. Alcohol use disorders and the Division 12 Task Force of the American Psychological Association.

    Science.gov (United States)

    McCrady, B S

    2000-09-01

    The Division 12 Task Force on Promotion and Dissemination of Psychological Procedures promulgated guidelines to identify treatments with empirical support for effectiveness. No treatment for alcohol abuse or dependence was rated as efficacious; 4 treatments for other drug use disorders were rated "probably efficacious." The alcohol treatment research community has questioned why alcohol treatments with strong empirical support are not in the task force's list. This article presents results of the application of task force standards to 13 major psychosocial alcohol treatments viewed as having strong empirical support. Brief intervention and relapse prevention met task force criteria for "efficacious" treatments. However, in 1996, when the task force last published a list of empirically supported treatments (D. L. Chambless et al., 1996), there were insufficient published studies meeting task force criteria for these 2 treatments. Motivational enhancement met criteria to be rated "probably efficacious."

  14. Transcription Against an Applied Force

    Science.gov (United States)

    Yin, Hong; Wang, Michelle D.; Svoboda, Karel; Landick, Robert; Block, Steven M.; Gelles, Jeff

    1995-12-01

    The force produced by a single molecule of Escherichia coli RNA polymerase during transcription was measured optically. Polymerase immobilized on a surface was used to transcribe a DNA template attached to a polystyrene bead 0.5 micrometer in diameter. The bead position was measured by interferometry while a force opposing translocation of the polymerase along the DNA was applied with an optical trap. At saturating nucleoside triphosphate concentrations, polymerase molecules stalled reversibly at a mean applied force estimated to be 14 piconewtons. This force is substantially larger than those measured for the cytoskeletal motors kinesin and myosin and exceeds mechanical loads that are estimated to oppose transcriptional elongation in vivo. The data are consistent with efficient conversion of the free energy liberated by RNA synthesis into mechanical work.

  15. Logic circuits from zero forcing

    CERN Document Server

    Burgarth, Daniel; Hogben, Leslie; Severini, Simone; Young, Michael

    2011-01-01

    We design logical circuits based on the notion of zero forcing on graphs; each gate of the circuits is a gadget in which zero forcing is performed. We show that such circuits can evaluate every monotone Boolean function. By using two vertices to encode each logical bit, we obtain universal computation. We also highlight a phenomenon of "back forcing" as a property of each function. Such a phenomenon occurs in a circuit when the input of gates which have been already used at a given time step is further modified by a computation actually performed at a later stage. Finally, we show that zero forcing can be also used to implement reversible computation. The model introduced here provides a potentially new tool in the analysis of Boolean functions, with particular attention to monotonicity.

  16. Electromagnetic force distribution inside matter

    CERN Document Server

    Mansuripur, Masud; Wright, Ewan M

    2013-01-01

    Using the Finite Difference Time Domain method, we solve Maxwell's equations numerically and compute the distribution of electromagnetic fields and forces inside material media. The media are generally specified by their dielectric permittivity epsilon(w) and magnetic permeability mu(w), representing small, transparent dielectric and magnetic objects such as platelets and micro-beads. Using two formulations of the electromagnetic force-density, one due to H. A. Lorentz [Collected Papers 2, 164 (1892)], the other due to A. Einstein and J. Laub [Ann, Phys. 331, 541 (1908)], we show that the force-density distribution inside a given object can differ substantially between the two formulations. This is remarkable, considering that the total force experienced by the object is always the same, irrespective of whether the Lorentz or the Einstein-Laub formula is employed. The differences between the two formulations should be accessible to measurement in deformable objects.

  17. Teleoperation with virtual force feedback

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.J.

    1993-08-01

    In this paper we describe an algorithm for generating virtual forces in a bilateral teleoperator system. The virtual forces are generated from a world model and are used to provide real-time obstacle avoidance and guidance capabilities. The algorithm requires that the slaves tool and every object in the environment be decomposed into convex polyhedral Primitives. Intrusion distance and extraction vectors are then derived at every time step by applying Gilbert`s polyhedra distance algorithm, which has been adapted for the task. This information is then used to determine the compression and location of nonlinear virtual spring-dampers whose total force is summed and applied to the manipulator/teleoperator system. Experimental results validate the whole approach, showing that it is possible to compute the algorithm and generate realistic, useful psuedo forces for a bilateral teleoperator system using standard VME bus hardware.

  18. US Air Force Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Worksheets containing pilot balloon data computed from releases at Air Force stations in the western United States. Elevation and azimuth angles are used to compute...

  19. Democratic Control of Military Forces

    National Research Council Canada - National Science Library

    Smail Ostrakovic

    2011-01-01

    The transition requirement for post communism countries, especially the part that is about military forces is to establish those civil-military relation that will have prepared projects for awareness...

  20. Voice Force tulekul / Tõnu Ojala

    Index Scriptorium Estoniae

    Ojala, Tõnu, 1969-

    2005-01-01

    60. sünnipäeva tähistava Tallinna Tehnikaülikooli Akadeemilise Meeskoori juubelihooaja üritusest - a capella pop-gruppide festivalist Voice Force (kontserdid 12. nov. klubis Parlament ja 3. dets. Vene Kultuurikeskuses)