WorldWideScience

Sample records for force change rate

  1. 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.

  2. 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...

  3. 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.

  4. 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...

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Forces of Change.

    Science.gov (United States)

    Kellogg, John B.

    1988-01-01

    Reviews U.S. immigration history, highlighting the three great migrations, the newest immigrants, their lands of origin (Asia and Latin America), major settlement areas and characteristics, the wave theory of immigration, reasons for immigrating, the changing face of America, and challenges for the schools (higher minority enrollments and…

  10. 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...

  11. 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.

  12. 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

  13. 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.

  14. 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....

  15. 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.

  16. 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)

  17. 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.

  18. Forced migrations caused by climate change

    Directory of Open Access Journals (Sweden)

    Neven Tandarić

    2014-06-01

    Full Text Available The consequences of climate change are becoming more and more pronounced, causing various environmental and social changes. One of the major and globally most noticeable changes is the intensification of forced migration caused by climate change. Such forced migrants, due to international legislation that has no built-in criteria to regulate the status of refugees due to environmental reasons and also climate change, cannot achieve this status and are becoming a problem of the entire international community, leading to significant social, economic, political and cultural changes at a global scale.

  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. Force sensor using changes in magnetic flux

    Science.gov (United States)

    Pickens, Herman L. (Inventor); Richard, James A. (Inventor)

    2012-01-01

    A force sensor includes a magnetostrictive material and a magnetic field generator positioned in proximity thereto. A magnetic field is induced in and surrounding the magnetostrictive material such that lines of magnetic flux pass through the magnetostrictive material. A sensor positioned in the vicinity of the magnetostrictive material measures changes in one of flux angle and flux density when the magnetostrictive material experiences an applied force that is aligned with the lines of magnetic flux.

  1. Management of change through force field analysis.

    Science.gov (United States)

    Baulcomb, Jean Sandra

    2003-07-01

    Today's NHS is rapidly changing, placing more emphasis on the managerial responsibilities of ward managers. Managing change is seen as being skilled at creating, acquiring and transferring knowledge to reflect new knowledge and insights. Defining core concepts is often difficult and requires the drawing on models/theories of change for guidance. Guidance from Lewin's (1951) force field analysis demonstrates the complexities of the change process and how driving and resisting forces were incorporated within the planning and implementation phases. Findings outline the benefits of a small scale change for staff, patients and the organization when successfully used to introduce a change of shift pattern within a progressively busy haematology day unit, in order to meet service demands without additional funding. Conclusions have been drawn in relation to the process and recommendations for practice made to further enhance care delivery within the unit.

  2. 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.

  3. Internal and External Forces in Language Change.

    Science.gov (United States)

    Yang, Charles D.

    2000-01-01

    Develops a model of language change characterizing the dynamic interaction between internal universal grammar and external linguistic evidence, as mediated by language acquisition. Borrows insights from the study of biological evolution, where internal and external forces interact in similar fashion. Applies the model to explore the loss of the…

  4. Patterns of Change: Forces and Motion

    Science.gov (United States)

    Phillips, Marianne; Jeffery, Tonya D.

    2016-01-01

    Patterns of Change: Forces and Motion is an integrated science lesson that uses the 5E lesson cycle to tie together science with language arts, mathematics, literature, technology, engineering and social studies in an engaging format applicable for young learners. This lesson has been uniquely designed for the purpose of providing elementary…

  5. Patterns of Change: Forces and Motion

    Science.gov (United States)

    Phillips, Marianne; Jeffery, Tonya D.

    2016-01-01

    Patterns of Change: Forces and Motion is an integrated science lesson that uses the 5E lesson cycle to tie together science with language arts, mathematics, literature, technology, engineering and social studies in an engaging format applicable for young learners. This lesson has been uniquely designed for the purpose of providing elementary…

  6. Illinois task force on global climate change

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, B.S. [Illinois Dept. of Natural Resources, Springfield, IL (United States)

    1996-12-31

    The purpose of this report is to document progress in the areas of national policy development, emissions reduction, research and education, and adaptation, and to identify specific actions that will be undertaken to implement the Illinois state action plan. The task force has been tracking national and international climate change policy, and helping shape national policy agenda. Identification and implementation of cost-effective mitigation measures has been performed for emissions reduction. In the area of research and education, the task force is developing the capacity to measure climate change indicators, maintaining and enhancing Illinois relevant research, and strengthening climate change education. Activities relevant to adaptation to new policy include strengthening water laws and planning for adaptation. 6 figs., 4 tabs.

  7. 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.

  8. 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.

  9. 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.

  10. 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…

  11. 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.

  12. 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.

  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.

    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

  14. 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.

  15. 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

  16. 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…

  17. 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.

  18. Retinal Changes Induced by Epiretinal Tangential Forces

    Directory of Open Access Journals (Sweden)

    Mario R. Romano

    2015-01-01

    Full Text Available Two kinds of forces are active in vitreoretinal traction diseases: tangential and anterior-posterior forces. However, tangential forces are less characterized and classified in literature compared to the anterior-posterior ones. Tangential epiretinal forces are mainly due to anomalous posterior vitreous detachment (PVD, vitreoschisis, vitreopapillary adhesion (VPA, and epiretinal membranes (ERMs. Anomalous PVD plays a key role in the formation of the tangential vectorial forces on the retinal surface as consequence of gel liquefaction (synchysis without sufficient and fast vitreous dehiscence at the vitreoretinal interface. The anomalous and persistent adherence of the posterior hyaloid to the retina can lead to vitreomacular/vitreopapillary adhesion or to a formation of avascular fibrocellular tissue (ERM resulting from the proliferation and transdifferentiation of hyalocytes resident in the cortical vitreous remnants after vitreoschisis. The right interpretation of the forces involved in the epiretinal tangential tractions helps in a better definition of diagnosis, progression, prognosis, and surgical outcomes of vitreomacular interfaces.

  19. CHANGES IN EXCHANGE RATE REGIMES

    Directory of Open Access Journals (Sweden)

    Carmen SANDU (TODERASCU

    2014-06-01

    Full Text Available The experience of recentyears showsthat it hasa fundamentalroleformation mechanismof the exchange rateinmacroeconomic stabilization. Global economiccrises, oil shockshave shownthe difficultyoffloatingsustainabilitybyparticipants in the system. EuropeanMonetary System, focused onconcertedfloatingcurrenciestoECU, was formedunder the conditionsin which somecountries have adoptedregional monetaryarrangements(EU countries, with suchbasescurrencyregimeshybridthat combinesspecific mechanismsto those offixedratefree floating. This paperaims to demonstratethe important role thatithasthe choice ofexchange rateregimeas abasic elementin thefoundationofmacroeconomic stabilizationinstruments. Consideredan expression of thestateof the domestic economyandinternationalcompetitiveness, the exchange rate is determined bya complex set ofexternal factorsorinternalstabilityisa prerequisite forthe crisis.

  20. An "Emergent Model" for Rate of Change

    Science.gov (United States)

    Herbert, Sandra; Pierce, Robyn

    2008-01-01

    Does speed provide a "model for" rate of change in other contexts? Does JavaMathWorlds (JMW), animated simulation software, assist in the development of the "model for" rate of change? This project investigates the transference of understandings of rate gained in a motion context to a non-motion context. Students were 27 14-15 year old students at…

  1. 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.

  2. 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.

  3. 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.

  4. 78 FR 69711 - Change in Postal Rates

    Science.gov (United States)

    2013-11-20

    ..., Priority Mail International (PMI) prices increase by an average of 1.1 percent. The existing price structure of PMI Flat Rate, Retail, Commercial Base, and Commercial Plus price categories do not change, except for the establishment of PMI Flat Rate Commercial Base and PMI Flat Rate Commercial Plus rates...

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Response rate, latency, and resistance to change

    Science.gov (United States)

    Fath, Stephen J.; Fields, Lanny; Malott, M. Kay; Grossett, Deborah

    1983-01-01

    Pigeons were trained on a multiple variable-interval/variable-interval schedule with pacing contingencies that generated high response rates in one component and low response rates in the other. Timeout periods separated the schedule components. During resistance-to-change tests, response-independent food was presented during the timeout periods, and the duration of that food presentation was varied among test sessions. Response rates in the schedule components decreased and latencies to the first response increased as a function of the duration of food presentations during the timeout. Both dependent measures changed about the same amount relative to their own baseline levels. The conclusions are that baseline response rates controlled by pacing contingencies are equally resistant to change, given equal reinforcement densities, and latency is a sensitive measure of resistance to change. PMID:16812319

  10. 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

  11. Optimal plane change by low aerodynamic forces

    Science.gov (United States)

    Vinh, Nguyen X.; Ma, Der-Ming

    1990-01-01

    This paper presents the exact dimensionless equations of motion and the necessary conditions for the computation of the optimal trajectories of a hypervelocity vehicle flying through a nonrotating spherical planetary atmosphere. It is shown that there are two types of maneuvers with nearly identical plane change. In the hard maneuver, the vehicle is pulled down to low altitude for aerodyamic plane change before exit at the prescribed final speed. In the slow maneuver which is described in detail in this paper, the vehicle remains in orbital flight with a small incremental plane change during each passage through the perigee. This maneuver requires several revolutions, and the technique for computation is similar to that in the problem of contraction of orbit.

  12. Organizational Change in the United States Air Force

    Science.gov (United States)

    2003-01-14

    organizational change on the part of the Air Force. This exploratory study analyzes the transition between the Cold War and post-Cold War periods to identify key variables in the organizational change process that might be susceptible to policy intervention. In particular, it highlights the importance of an external change agent in the form of a directed change in mission, or an internal change agent in the form of organizational learning, as essential factors in transforming the Air Force’s organizational strategy, which is the first step in

  13. 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…

  14. 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…

  15. Exporter Price Response to Exchange Rate Changes

    DEFF Research Database (Denmark)

    Fosse, Henrik Barslund

    Firms exporting to foreign markets face a particular challenge: to price their exports in a foreign market when the exchange rate changes. This paper takes on pricing- to-market using a unique data set that covers rm level monthly trade at great detail. As opposed to annual trade ows, monthly trade...... theoretical contributions to the litterature on pricing-to-market and exchange rate pass-through....

  16. Climate change forces new ecological states in tropical Andean lakes.

    Directory of Open Access Journals (Sweden)

    Neal Michelutti

    Full Text Available Air temperatures in the tropical Andes have risen at an accelerated rate relative to the global average over recent decades. However, the effects of climate change on Andean lakes, which are vital to sustaining regional biodiversity and serve as an important water resource to local populations, remain largely unknown. Here, we show that recent climate changes have forced alpine lakes of the equatorial Andes towards new ecological and physical states, in close synchrony to the rapid shrinkage of glaciers regionally. Using dated sediment cores from three lakes in the southern Sierra of Ecuador, we record abrupt increases in the planktonic thalassiosiroid diatom Discostella stelligera from trace abundances to dominance within the phytoplankton. This unprecedented shift occurs against the backdrop of rising temperatures, changing atmospheric pressure fields, and declining wind speeds. Ecological restructuring in these lakes is linked to warming and/or enhanced water column stratification. In contrast to seasonally ice-covered Arctic and temperate alpine counterparts, aquatic production has not increased universally with warming, and has even declined in some lakes, possibly because enhanced thermal stability impedes the re-circulation of hypolimnetic nutrients to surface waters. Our results demonstrate that these lakes have already passed important ecological thresholds, with potentially far-reaching consequences for Andean water resources.

  17. Effective radiative forcing from historical land use change

    Science.gov (United States)

    Andrews, Timothy; Betts, Richard A.; Booth, Ben B. B.; Jones, Chris D.; Jones, Gareth S.

    2017-06-01

    The effective radiative forcing (ERF) from the biogeophysical effects of historical land use change is quantified using the atmospheric component of the Met Office Hadley Centre Earth System model HadGEM2-ES. The global ERF at 2005 relative to 1860 (1700) is -0.4 (-0.5) Wm-2, making it the fourth most important anthropogenic driver of climate change over the historical period (1860-2005) in this model and larger than most other published values. The land use ERF is found to be dominated by increases in the land surface albedo, particularly in North America and Eurasia, and occurs most strongly in the northern hemisphere winter and spring when the effect of unmasking underlying snow, as well as increasing the amount of snow, is at its largest. Increased bare soil fraction enhances the seasonal cycle of atmospheric dust and further enhances the ERF. Clouds are shown to substantially mask the radiative effect of changes in the underlying surface albedo. Coupled atmosphere-ocean simulations forced only with time-varying historical land use change shows substantial global cooling (d T = -0.35 K by 2005) and the climate resistance (ERF/d T = 1.2 Wm-2 K-1) is consistent with the response of the model to increases in CO2 alone. The regional variation in land surface temperature change, in both fixed-SST and coupled atmosphere-ocean simulations, is found to be well correlated with the spatial pattern of the forced change in surface albedo. The forcing-response concept is found to work well for historical land use forcing—at least in our model and when the forcing is quantified by ERF. Our results suggest that land-use changes over the past century may represent a more important driver of historical climate change then previously recognised and an underappreciated source of uncertainty in global forcings and temperature trends over the historical period.

  18. Multivariate analysis of longitudinal rates of change.

    Science.gov (United States)

    Bryan, Matthew; Heagerty, Patrick J

    2016-12-10

    Longitudinal data allow direct comparison of the change in patient outcomes associated with treatment or exposure. Frequently, several longitudinal measures are collected that either reflect a common underlying health status, or characterize processes that are influenced in a similar way by covariates such as exposure or demographic characteristics. Statistical methods that can combine multivariate response variables into common measures of covariate effects have been proposed in the literature. Current methods for characterizing the relationship between covariates and the rate of change in multivariate outcomes are limited to select models. For example, 'accelerated time' methods have been developed which assume that covariates rescale time in longitudinal models for disease progression. In this manuscript, we detail an alternative multivariate model formulation that directly structures longitudinal rates of change and that permits a common covariate effect across multiple outcomes. We detail maximum likelihood estimation for a multivariate longitudinal mixed model. We show via asymptotic calculations the potential gain in power that may be achieved with a common analysis of multiple outcomes. We apply the proposed methods to the analysis of a trivariate outcome for infant growth and compare rates of change for HIV infected and uninfected infants. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Predicting the Expected Rate of Change

    Institute of Scientific and Technical Information of China (English)

    吴梦想

    2016-01-01

    Since December 2013,Ebola outbreak in west Africa again, and the year's disease was the most serious Ebola serious, which arouse the global attention. We are consider that among the countries where outbreak Ebola disease, Nigeria has the most serious problem. So we choose Nigeria as our object, establish differential equation and take the initial value to calculate, expecting rate of change in the number of Ebola infections for the country from 2006 to 2015, in the absence of any additional drugs. Clearly giving the inspecting time, we can get the change of the number of healthy people and the patients.

  20. Anthropogenic Aerosols in Asia, Radiative Forcing, and Climate Change

    Science.gov (United States)

    Ramaswamy, V.; Bollasina, M. A.; Ming, Y.; Ocko, I.; Persad, G.

    2014-12-01

    Aerosols arising as a result of human-induced emissions in Asia form a key 'driver' in causing pollution and in the forcing of anthropogenic climate change. The manner of the forced climate change is sensitive to the scattering and absorption properties of the aerosols and the aerosol-cloud microphysical interactions. Using the NOAA/ GFDL global climate models and observations from multiple platforms, we investigate the radiative perturbations due to the 20th Century sulfate and carbonaceous aerosol emissions and the resultant impacts on surface temperature, tropical precipitation, Indian monsoon, hemispheric circulation, and atmospheric and oceanic heat transports. The influence of the aerosol species has many contrasts with that due to the anthropogenic well-mixed greenhouse gas emissions e.g., the asymmetry in the hemispheric climate response, but is subject to larger uncertainties. The aerosol forcing expected in the future indicates a significant control on the 21st Century anthropogenic climate change in Asia.

  1. Changes in a coflowing jet structure caused by acoustic forcing

    Energy Technology Data Exchange (ETDEWEB)

    Cerecedo, Luis M.; Aisa, Luis; Garcia, Juan A.; Santolaya, Jose L. [Fluid Mechanics Department, University of Zaragoza, Zaragoza (Spain)

    2004-06-01

    In the present work, the changes in the basic turbulence field of an axisymmetric jet in a coflow when acoustic forcing is applied are investigated. The main objective is to discriminate between changes produced by the acoustic forcing and those produced by the presence of solid particles in a two-phase flow. Power spectra of the axial velocities, u(t), are analyzed to reinforce the idea of the existence of a natural frequency. Time-averaged data are used to characterize the basic flow. This basic flow is compared with the flow altered by the acoustic forcing. By smoothing the phase-averaged rms data (mean statistical curve), the general behavior of the instantaneous fluctuations are unveiled and compared with that of the natural (unforced) jet. In this way, it can be seen that rms values in the forced cases are higher than in the unforced ones, due to the contribution of the external forcing. However, once the coherent structures are extinguished, both forced and unforced jets show a similar trend. (orig.)

  2. Optimal plane changes using third-body forces.

    Science.gov (United States)

    Villac, B F; Scheeres, D J

    2004-05-01

    The fuel optimality of third-body driven plane changes (i.e., plane changes performed by using third-body forces) over one-impulse transfers is investigated numerically and analytically. In particular, the range of third-body driven plane changes that are realizable is shown to be restricted and one impulse must be used in the uncovered regions. However, when third-body driven plane changes are realizable, it is shown that they are always optimal above a certain critical value (about 40 degrees ) that depends on the initial condition. Contour plots of optimal DeltaV values to perform a desired plane changes are given.

  3. The Potential Radiative Forcing of Global Land Use and Land Cover Change Activities

    Science.gov (United States)

    Ward, D. S.; Mahowald, N. M.; Kloster, S.

    2014-12-01

    Given the expected increase in pressure on land resources over the next century, there is a need to understand the total impacts of activities associated with land use and land cover change (LULCC). Here we quantify these impacts using the radiative forcing metric, including forcings from changes in long-lived greenhouse gases, tropospheric ozone, aerosol effects, and land surface albedo. We estimate radiative forcings from the different agents for historical LULCC and for six future projections using simulations from the National Center for Atmospheric Research Community Land Model and Community Atmosphere Models and additional offline analyses. When all forcing agents are considered together we show that 45% (+30%, -20%) of the present-day (2010) anthropogenic radiative forcing can be attributed to LULCC. Changes in the emission of non-CO2 greenhouse gases and aerosols from LULCC enhance the total LULCC radiative forcing by a factor of 2 to 3 with respect to the forcing from CO2 alone. In contrast, the non-CO2 forcings from fossil fuel burning are roughly neutral, due largely to the negative (cooling) impact of aerosols from these sources. We partition the global LULCC radiative forcing into three major sources: direct modification of land cover (e.g. deforestation), agricultural activities, and fire regime changes. Contributions from deforestation and agriculture are roughly equal in the present day, while changes to wildfire activity impose a small negative forcing globally. In 2100, deforestation activities comprise the majority of the LULCC radiative forcing for all projections except one (Representative Concentration Pathway (RCP) 4.5). This suggests that realistic scenarios of future forest area change are essential for projecting the contribution of LULCC to climate change. However, the commonly used RCP land cover change projections all include decreases in global deforestation rates over the next 85 years. To place an upper bound on the potential

  4. Natural selection and cultural rates of change.

    Science.gov (United States)

    Rogers, Deborah S; Ehrlich, Paul R

    2008-03-04

    It has been claimed that a meaningful theory of cultural evolution is not possible because human beliefs and behaviors do not follow predictable patterns. However, theoretical models of cultural transmission and observations of the development of societies suggest that patterns in cultural evolution do occur. Here, we analyze whether two sets of related cultural traits, one tested against the environment and the other not, evolve at different rates in the same populations. Using functional and symbolic design features for Polynesian canoes, we show that natural selection apparently slows the evolution of functional structures, whereas symbolic designs differentiate more rapidly. This finding indicates that cultural change, like genetic evolution, can follow theoretically derived patterns.

  5. Force-Induced Changes in Subnuclear Movement and Rheology

    Science.gov (United States)

    Booth-Gauthier, Elizabeth A.; Alcoser, Turi A.; Yang, Ge; Dahl, Kris N.

    2012-01-01

    Extracellular mechanical forces result in changes in gene expression, but it is unclear how cells are able to permanently adapt to new mechanical environments because chemical signaling pathways are short-lived. We visualize force-induced changes in nuclear rheology to examine short- and long-time genome organization and movements. Punctate labels in the nuclear interior of HeLa, human umbilical vein endothelial, and osteosarcoma (Saos-2) cells allow tracking of nuclear movements in cells under varying levels of shear and compressive force. Under adequate shear stress two distinct regimes develop in cells under mechanical stimulation: an initial event of increased intranuclear movement followed by a regime of intranuclear movements that reflect the dose of applied force. At early times there is a nondirectionally oriented response with a small increase in nuclear translocations. After 30 min, there is a significant increase in nuclear movements, which scales with the amount of shear or compressive stress. The similarities in the nuclear response to shear and compressive stress suggest that the nucleus is a mechanosensitive element within the cell. Thus, applied extracellular forces stimulate intranuclear movements, resulting in repositioning of nuclear bodies and the associated chromatin within the nucleus. PMID:23260044

  6. 75 FR 69142 - Postal Rate and Classification Changes

    Science.gov (United States)

    2010-11-10

    ... Postal Rate and Classification Changes AGENCY: Postal Regulatory Commission. ACTION: Notice. SUMMARY: The... its intention of planned rate and classification changes rates for certain competitive domestic and... competitive products.\\1\\ The Filing also includes related mail classification changes. The Postal...

  7. 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...

  8. 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...

  9. Changes in forced expiratory volume in 1 second over time in COPD

    DEFF Research Database (Denmark)

    Vestbo, Jørgen; Edwards, Lisa D; Scanlon, Paul D

    2011-01-01

    A key feature of chronic obstructive pulmonary disease (COPD) is an accelerated rate of decline in forced expiratory volume in 1 second (FEV(1)), but data on the variability and determinants of this change in patients who have established disease are scarce....

  10. Changes in forced expiratory volume in 1 second over time in COPD

    DEFF Research Database (Denmark)

    Vestbo, Jørgen; Edwards, Lisa D; Scanlon, Paul D

    2011-01-01

    A key feature of chronic obstructive pulmonary disease (COPD) is an accelerated rate of decline in forced expiratory volume in 1 second (FEV(1)), but data on the variability and determinants of this change in patients who have established disease are scarce....

  11. 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

  12. The driving forces of landscape change in Europe

    DEFF Research Database (Denmark)

    Plieninger, Tobias; Draux, Hélène; Fagerholm, Nora

    2016-01-01

    underrepresented landscapes; (b) clarifying the identification and role of actors in landscape change; (c) deploying more robust tools and methods to quantitatively assess the causalities of landscape change; (d) setting up long-term studies that go beyond mapping land-cover change only; (e) strengthening cross......Over the past decades, landscapes worldwide have experienced changes (e.g., urbanization, agricultural intensification, expansion of renewable energy uses) at magnitudes that put their sustainability at risk. The understanding of the drivers of these landscape changes remains challenging, partly...... because landscape research is spread across many domains and disciplines. We here provide a systematic synthesis of 144 studies that identify the proximate and underlying drivers of landscape change across Europe. First, we categorize how driving forces have been addressed and find that most studies...

  13. CHANGE@CERN:Task Force 4: Matching personnel to activities

    CERN Multimedia

    2002-01-01

    Our series on the work of the Task Forces moves on to Human Ressources at CERN. Staff mobility and topics related to contract policy were the main personnel issues to be considered by Task Force 4, led by John Ferguson, head of AS Division. The aim, as with the other Task Forces, was to find ways to focus resources on the LHC, and once again the recommendations recognise the opportunity to make constructive changes, in this case in Human Resources policy at CERN. Movement of staff between divisions at CERN has generally not been easy, with 'staff complements' (total numbers) set for each sector (research, accelerator, technical and administration). However, the restructuring of the accelerator sector (proposed by Task Force 5 and already agreed in principle) should allow some staff to move to LHC activities. More generally, Task Force 4 recommends that the Laboratory carries out a review of all activities, at a relatively detailed level, so as to identify the resources required to achieve specific goals (t...

  14. Detection of temporal changes in earthquake rates

    Science.gov (United States)

    Touati, S.

    2012-12-01

    Many statistical analyses of earthquake rates and time-dependent forecasting of future rates involve the detection of changes in the basic rate of events, independent of the fluctuations caused by aftershock sequences. We examine some of the statistical techniques for inferring these changes, using both real and synthetic earthquake data to check the statistical significance of these inferences. One common method is to use the Akaike Information Criterion (AIC) to choose between a single model and a double model with a changepoint; this criterion evaluates the strength of the fit and incorporates a penalty for the extra parameters. We test this method on many realisations of the ETAS model, with and without changepoints present, to see how often it chooses the correct model. A more rigorous method is to calculate the Bayesian evidence, or marginal likelihood, for each model and then compare these. The evidence is essentially the likelihood of the model integrated over the whole of the model space, giving a measure of how likely the data is for that model. It does not rely on estimation of best-fit parameters, making it a better comparator than the AIC; Occam's razor also arises naturally in this process due to the fact that more complex models tend to be able to explain a larger range of observations, and therefore the relative likelihood of any particular observations will be smaller than for a simpler model. Evidence can be calculated using Markov Chain Monte Carlo techniques. We compare these two approaches on synthetic data. We also look at the 1997-98 Colfiorito sequence in Umbria-Marche, Italy, using maximum likelihood to fit the ETAS model and then simulating the ETAS model to create synthetic versions of the catalogue for comparison. We simulate using ensembles of parameter values sampled from the posterior for each parameter, with the largest events artificially inserted, to compare the resultant event rates, inter-event time distributions and other

  15. 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...

  16. Nonlinear Insolation Forcing: A Physical Mechanism for Climate Change

    Science.gov (United States)

    Liu, H. S.

    1998-01-01

    This paper focuses on recent advances in the understanding of nonlinear insolation forcing for climate change. The amplitude-frequency resonances in the insolation variations induced by the Earth's changing obliquity are emergent and may provide a physical mechanism to drive the glaciation cycles. To establish the criterion that nonlinear insolation forcing is responsible for major climate changes, the cooperative phenomena between the frequency and amplitude of the insolation are defined as insolation pulsation. Coupling of the insolation frequency and amplitude variations has established an especially new and interesting series of insolation pulses. These pulses would modulate the insolation in such a way that the mode of insolation variations could be locked to generate the 100-kyr ice age cycle which is a long-time geophysical puzzle. The nonlinear behavior of insolation forcing is tested by energy balance and ice sheet climate models and the physical mechanism behind this forcing is explained in terms of pulse duration in the incoming solar radiation. Calculations of the solar energy flux at the top of the atmosphere show that the duration of the negative and positive insolation pulses is about 2 thousand years which is long enough to prolong glaciation into deep ice ages and cause rapid melting of large ice sheets in the high latitudes of the northern hemisphere. We have performed numerical simulations of climate response to nonlinear insolation forcing for the past 2 million years. Our calculated results of temperature fluctuations are in good agreement with the climate cycles as seen in the terrestrial biogenic silica (BDP-96-2) data as well as in the marine oxygen isotope (delta(sup 18)O) records.

  17. 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.

  18. 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.

  19. 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.

  20. Do Diurnal Aerosol Changes Affect Daily Average Radiative Forcing?

    Energy Technology Data Exchange (ETDEWEB)

    Kassianov, Evgueni I.; Barnard, James C.; Pekour, Mikhail S.; Berg, Larry K.; Michalsky, Joseph J.; Lantz, K.; Hodges, G. B.

    2013-06-17

    Strong diurnal variability of aerosol has been observed frequently for many urban/industrial regions. How this variability may alter the direct aerosol radiative forcing (DARF), however, is largely unknown. To quantify changes in the time-averaged DARF, we perform an assessment of 29 days of high temporal resolution ground-based data collected during the Two-Column Aerosol Project (TCAP) on Cape Cod, which is downwind of metropolitan areas. We demonstrate that strong diurnal changes of aerosol loading (about 20% on average) have a negligible impact on the 24-h average DARF, when daily averaged optical properties are used to find this quantity. However, when there is a sparse temporal sampling of aerosol properties, which may preclude the calculation of daily averaged optical properties, large errors (up to 100%) in the computed DARF may occur. We describe a simple way of reducing these errors, which suggests the minimal temporal sampling needed to accurately find the forcing.

  1. 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.

  2. 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.

  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. 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...

  5. 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.

  6. 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.

  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. Changes in muscle strength and morphology after muscle unloading in Special Forces missions

    DEFF Research Database (Denmark)

    Thorlund, J B; Jakobsen, O; Madsen, T

    2011-01-01

    The purpose of the present study was to determine the changes in maximal muscle strength, rapid force capacity, jumping performance and muscle morphology following a Special Forces military operation involving 8 days of muscle unloading. Nine male Special Forces soldiers were tested before (pre......) and immediately after (post1) an 8-day simulated special support and reconnaissance (SSR) mission and after 3 h of active recovery (post2). Maximal muscle strength (MVC) and rate of force development (RFD) were measured along with maximal counter movement jump height (JH). Muscle biopsies were obtained from...... the vastus lateralis at pre and post1. Acute reductions were found in MVC (11%), JH (10%) and RFD (17-22%) after 8 days of muscle unloading (post1) (P...

  9. 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...

  10. The effect of temporal and force changes on the patterning of sequential movements.

    Science.gov (United States)

    Piek, J P; Glencross, D J; Barrett, N C; Love, G L

    1993-01-01

    This article examines the programming of relatively long sequences of action with the control of sequential movements being effected through the use of a tapping task involving a sequence of five taps. Subjects were required to tap with their right hand at rates of 150, 200, and 250 ms. There were two conditions, with subjects being required either to increase, in condition 1, or to decrease, in condition 2, the force at one of the five tap positions (all five tap positions were examined), then return to the previous force level. Changes in timing resulting from variations in the force characteristics have previously been discussed in terms of changes in the organizational time required (Semjen, Garcia-Colera, & Requin, 1984). The current study breaks the intertap interval down into two separate components: the contact interval (finger in contact with the key) and the non-contact interval (interval preceding the tap). Although changes in the non-contact interval could be explained in terms of changes in the organizational time required, changes in the contact interval appeared to be a result of the mechanical changes in force.

  11. 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

  12. 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.

  13. Maternal heart rate changes during labour.

    Science.gov (United States)

    Söhnchen, N; Melzer, K; Tejada, B Martinez de; Jastrow-Meyer, N; Othenin-Girard, V; Irion, O; Boulvain, M; Kayser, B

    2011-10-01

    Labour and delivery represent a considerable effort for pregnant women. Lack of aerobic fitness may limit pushing efforts during childbirth and represents increased cardiovascular strain and risk. Increasing prevalence of sedentary behaviour and lack of aerobic fitness may reduce heart rate reserve during labour. We quantified maternal heart rate reserve (maximum heart rate minus resting heart rate) of 30 healthy pregnant women during labour and delivery and related it to habitual daily physical activity levels quantified during the third pregnancy trimester by the Pregnancy Physical Activity Questionnaire. Heart rates during labour reached values similar to those observed during moderate to heavy physical exercise. During active pushing one out of five women reached heart rates more than 90% of their heart rate reserve (188 ± 7 beats per min). Half of the women reached more than 70% of heart rate reserve (172 ± 14 beats per min). Physically inactive women used more of their heart rate reserve as physically more active women (87 ± 20% vs. 65 ± 12%, upper and lower tertile respectively, plabour is increased in physically inactive women and may potentially limit the intensity and duration of pushing efforts. Such higher cardiovascular strain in physically less active women may represent increased cardiovascular risk during labour. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. Change Agent – A Force Generating Resistance To Change Within An Organization?

    Directory of Open Access Journals (Sweden)

    Mariana Prediscan

    2012-12-01

    Full Text Available The purpose of this research is to identify if the change agent represents or not a force generating resistance to change within an organization. The employees affected by a change process are usually the ones who oppose to new implementations. Their opposition is bigger or smaller, depending on the extent that they are affected and also by the direction, either positive or negative. However, employee’s opposition can be potentiated or reduced, depending on the manifestation of the following forces within an organization: communications, the type of organizational structure, management style and organizational culture, forces which refer to the organizational climate. To answer our question, we have researched the current literature and discovered that the change agent can represent a force generating resistance to change within an organization in those situations when he or she identifies with a middle or top manager from the organizational pyramid. This information is valuable to researchers and practitioners, as for a long time, employees were considered the only ones manifesting resistance, the possibility that the change agent can oppose new changes being ignored.

  15. 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...

  16. 21st century change in ocean response to climate forcing

    CERN Document Server

    Marčelja, Stjepan

    2015-01-01

    Modeling globally averaged information on climate forcing from the land surface temperature data, the sea surface temperatures (SST) and the empirically determined relationship between the changes in SST and the turbulent diffusion of heat into the upper ocean demonstrates a consistent link. The modeling is accurate throughout the 20th century despite the different phases of the Interdecadal Pacific Oscillation (IPO) or the strong divergence between land and ocean surface warming. It only fails during the last 15 years when SST drops well below the trend. The finding reinforces the view that slower global warming over the previous 15 years is not a caused by a negative phase of the IPO or by the variations in the upper ocean (top 700 m) warming but results from a change in the ocean behavior leading to increased heat transfer into the deeper ocean.

  17. 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.

  18. Potential climate forcing of land use and land cover change

    Directory of Open Access Journals (Sweden)

    D. S. Ward

    2014-05-01

    Full Text Available Pressure on land resources is expected to increase as global population continues to climb and the world becomes more affluent, swelling the demand for food. Changing climate may exert additional pressures on natural lands as present day productive regions may shift, or soil quality may degrade, and the recent rise in demand for biofuels increases competition with edible crops for arable land. Given these projected trends there is a need to understand the global climate impacts of land use and land cover change (LULCC. Here we quantify the climate impacts of global LULCC in terms of modifications to the balance between incoming and outgoing radiation at the top of the atmosphere (radiative forcing; RF that are caused by changes in long-lived and short-lived greenhouse gas concentrations, aerosol effects and land surface albedo. We simulate historical changes to terrestrial carbon storage, global fire emissions, secondary organic aerosol emissions, and surface albedo from LULCC using the Community Land Model version 3.5. These LULCC emissions are combined with estimates of agricultural emissions of important trace gases and mineral dust in two sets of Community Atmosphere Model simulations to calculate the RF from LULCC impacts on atmospheric chemistry and changes in aerosol concentrations. With all forcing agents considered together, we show that 45% (+30%, −20% of the present-day anthropogenic RF can be attributed to LULCC. Changes in the emission of non-CO2 greenhouse gases and aerosols from LULCC enhance the total LULCC RF by a factor of 2 to 3 with respect to the LULCC RF from CO2 alone. This enhancement factor also applies to projected LULCC RF, which we compute for four future scenarios associated with the Representative Concentration Pathways. We calculate total RFs between 1 to 2 W m−2 from LULCC for the year 2100 (relative to a preindustrial state. To place an upper bound on the potential of LULCC to alter the global radiation

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. CHANGE@CERN:Task Force 2: reshaping for the future

    CERN Multimedia

    2002-01-01

    Second in our series reviewing the Task Forces reports. How to lay the foundations for a more efficient organisational structure. Our present organization is based on sixteen Divisions and units under the Directorate. CERN's organization is based on a Directorate and sixteen Divisions and units, while its activities are broadly divided into four Sectors: Research, Accelerators, Technical and Administration. The mandate of Task Force 2, led by Horst Wenninger, was to identify if a structural change and a reduction of duplicated efforts could result in an increased efficiency at CERN, especially as the Laboratory continues to focus its resources on the LHC. 'This is the most difficult project ever undertaken at CERN', acknowledges Wenninger, 'a double accelerator at a temperature of 1.9 K'. For the next five years the success of the LHC must be the main priority, and CERN will have to adapt the procedures of how it works. Wenninger sees the process as an opportunity for the Laboratory to move into the 21st c...

  6. Holocene dynamics of vegetation change in southern and southeastern Brazil is consistent with climate forcing

    Science.gov (United States)

    Rodrigues, Jackson Martins; Behling, Hermann; Giesecke, Thomas

    2016-08-01

    At mid to high northern latitudes postglacial vegetation change has often occurred synchronously over large regions triggered mainly by abrupt climate change. Based on 19 pollen diagrams from southern and southeastern Brazil we explore if similar synchronicities in vegetation change were also characteristic for the vegetation dynamics in low latitudes. We used sequence splitting to detect past vegetation change in the pollen diagrams and computed principal curves and rates of change to visually evaluate the changes in composition and dynamics. The results show that vegetation change occurred mostly during the second half of the Holocene with distinct episodes of change. The character of vegetation change is generally consistent with shifts to wetter conditions and agrees with inferred shifts of the South American Monsoon. Speleothems as well as the titanium record from the Cariaco Basin indicate several episodes of rapid shifts in the precipitation regime, which are within the dating uncertainty of the here detected periods of vegetation change (8900, 5900, 2800, 1200 and 550 cal yrs BP). Our results indicate that low latitude vegetation composition follows precession forcing of the hydrology, while change is often triggered and synchronized by rapid climate change much like in high and mid latitudes. Pollen diagrams document changes in the abundance of individual taxa and changes in the amount of woodland cover, while small compositional changes indicate a regional stability of vegetation types during the Holocene.

  7. What Drives the European Central Bank's Interest-Rate Changes?

    DEFF Research Database (Denmark)

    Jensen, Henrik; Aastrup, Morten

    We show that the ECB's interest rate changes during 1999-2010 have been mainly driven by changes in economic activity in the Euro area. Changes in actual or expected future HICP inflation play a minor, if any, role.......We show that the ECB's interest rate changes during 1999-2010 have been mainly driven by changes in economic activity in the Euro area. Changes in actual or expected future HICP inflation play a minor, if any, role....

  8. 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...

  9. Changing Structures and Women’s Role as Labor Force

    Directory of Open Access Journals (Sweden)

    Lena Gonäs

    2015-06-01

    Full Text Available The objective of this paper is to analyze changes in the development of women’s role as labor force over a 40-year period. This is done by presenting research results that concern the restructuring of the labor market over different time periods. The empirical material is from the 1960s, the heyday of the Swedish model; from the 1980s, the period that economic historians label the third industrial revolution; and from the 1990s, a period labeled the new working life that is covering the reorganization of the public sector. For the first period results from restructuring in the shipyard industry are presented as well as employment outcomes for single individuals. This industry was male dominated with very few women employed, but regional policy measures were implemented to reach a latent female labor force. The second period is covered by a study of closures and cutbacks in different industries in Sweden during 1982–1983. The proportion of women employed in the industries studied was around one third and employment outcomes had a specific gendered pattern. Women did to a lower extent than men get new permanent jobs. Permanent temporariness was introduced as a concept to describe their labor market situation. The recession that one decade later hit both female- and male-dominated sectors is illustrated by a study of the relations between labor market attachment, working life, and family conditions. The material comes from a regional research program based on a questionnaire and on register data on incomes from 1990 to 1999. The paper analyzes several areas related to work and outside of work that indicate a gendered pattern of multidimensional subordination and an increased polarization in terms of both gender and class. In conclusion, the 40 years has been a period of dramatic change in women’s situation as labor force. In times of restructuring they often entered into precarious job situations or unemployment. Women’s double burden

  10. 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.

  11. 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

  12. 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.

  13. Delineating the Average Rate of Change in Longitudinal Models

    Science.gov (United States)

    Kelley, Ken; Maxwell, Scott E.

    2008-01-01

    The average rate of change is a concept that has been misunderstood in the literature. This article attempts to clarify the concept and show unequivocally the mathematical definition and meaning of the average rate of change in longitudinal models. The slope from the straight-line change model has at times been interpreted as if it were always the…

  14. 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.

  15. 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.

  16. Experimental evidence of landscape reorganization under changing external forcing: implications to climate-driven knickpoints

    Science.gov (United States)

    Singh, Arvind; Tejedor, Alejandro; Grimaud, Jean-Louis; Foufoula-Georgiou, Efi

    2017-04-01

    Understanding and quantifying geomorphic and topologic re-organization of landscape in response to changing climatic or tectonic forcing is of scientific and practical interest. Although several studies have addressed the large-scale response (e.g., change in mean relief), studies on the smaller-scale drainage pattern re-organization and quantification of landscape vulnerability to the timing, magnitude, and frequency of changing forcing are lacking. To that goal, a series of controlled laboratory experiments were conducted to study the effect of changing precipitation patterns on landscape evolution at the short and long-time scales. High resolution digital elevation (DEM) both in space and time were measured for a range of rainfall patterns and uplift rates. Results from our study show a distinct signature of the precipitation increase on the probabilistic and geometrical structure of landscape features, evident in widening and deepening of channels and valleys, change in drainage patterns within sub-basins and change in the space-time structure of erosional and depositional events. A spatially explicit analysis of the locus of these erosional and depositional events show an acceleration of erosion in the hillslopes when the rainfall intensity is increased, while the incision in fluvial channels is slowed down exhibiting a sediment-flux dependent behavior. Finally, we document the changes in the longitudinal river profiles with increasing precipitation intensity, revealing the formation of knickpoints at certain confluences where large discontinuities in the ratio Qs/Qw are observed.

  17. 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.

  18. A Determination of the Rate of Change of G

    Science.gov (United States)

    1975-02-01

    RATE OF CHANGE OF G Thomas C. Van...TITLE AND SUBTITLE A Determination Of The Rate Of Change Of G 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...related to the rate of change of G. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER

  19. 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

  20. Achilles tendinosis: Changes in biochemical composition and collagen turnover rate

    NARCIS (Netherlands)

    Mos, M. de; El, B. van; Groot, J. de; Jahr, H.; Schie, H.T.M. van; Arkel, E.R. van; Tol, H.; Heijboer, R.; Osch, G.J.V.M. van; Verhaar, J.A.N.

    2007-01-01

    Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. Study Design: Descript

  1. Achilles tendinosis - Changes in biochemical composition and collagen turnover rate

    NARCIS (Netherlands)

    de Mos, Marieke; van El, Benno; DeGroot, Jeroen; Jahr, Holger; van Schie, Hans T. M.; van Arkel, Ewoud R.; Tol, Hans; Heijboer, Rien; van Osch, Gerjo J. V. M.; Verhaar, Jan A. N.

    2007-01-01

    Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. Study Design: Descript

  2. Achilles tendinosis: Changes in biochemical composition and collagen turnover rate

    NARCIS (Netherlands)

    Mos, M. de; El, B. van; Groot, J. de; Jahr, H.; Schie, H.T.M. van; Arkel, E.R. van; Tol, H.; Heijboer, R.; Osch, G.J.V.M. van; Verhaar, J.A.N.

    2007-01-01

    Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. Study Design:

  3. Achilles tendinosis - Changes in biochemical composition and collagen turnover rate

    NARCIS (Netherlands)

    de Mos, Marieke; van El, Benno; DeGroot, Jeroen; Jahr, Holger; van Schie, Hans T. M.; van Arkel, Ewoud R.; Tol, Hans; Heijboer, Rien; van Osch, Gerjo J. V. M.; Verhaar, Jan A. N.

    Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. Study Design:

  4. Achilles tendinosis - Changes in biochemical composition and collagen turnover rate

    NARCIS (Netherlands)

    de Mos, Marieke; van El, Benno; DeGroot, Jeroen; Jahr, Holger; van Schie, Hans T. M.; van Arkel, Ewoud R.; Tol, Hans; Heijboer, Rien; van Osch, Gerjo J. V. M.; Verhaar, Jan A. N.

    2007-01-01

    Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. Study Design: Descript

  5. Achilles tendinosis: Changes in biochemical composition and collagen turnover rate

    NARCIS (Netherlands)

    Mos, M. de; El, B. van; Groot, J. de; Jahr, H.; Schie, H.T.M. van; Arkel, E.R. van; Tol, H.; Heijboer, R.; Osch, G.J.V.M. van; Verhaar, J.A.N.

    2007-01-01

    Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies. Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate. Study Design: Descript

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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....

  11. Divergent global precipitation changes induced by natural versus anthropogenic forcing.

    Science.gov (United States)

    Liu, Jian; Wang, Bin; Cane, Mark A; Yim, So-Young; Lee, June-Yi

    2013-01-31

    As a result of global warming, precipitation is likely to increase in high latitudes and the tropics and to decrease in already dry subtropical regions. The absolute magnitude and regional details of such changes, however, remain intensely debated. As is well known from El Niño studies, sea-surface-temperature gradients across the tropical Pacific Ocean can strongly influence global rainfall. Palaeoproxy evidence indicates that the difference between the warm west Pacific and the colder east Pacific increased in past periods when the Earth warmed as a result of increased solar radiation. In contrast, in most model projections of future greenhouse warming this gradient weakens. It has not been clear how to reconcile these two findings. Here we show in climate model simulations that the tropical Pacific sea-surface-temperature gradient increases when the warming is due to increased solar radiation and decreases when it is due to increased greenhouse-gas forcing. For the same global surface temperature increase the latter pattern produces less rainfall, notably over tropical land, which explains why in the model the late twentieth century is warmer than in the Medieval Warm Period (around AD 1000-1250) but precipitation is less. This difference is consistent with the global tropospheric energy budget, which requires a balance between the latent heat released in precipitation and radiative cooling. The tropospheric cooling is less for increased greenhouse gases, which add radiative absorbers to the troposphere, than for increased solar heating, which is concentrated at the Earth's surface. Thus warming due to increased greenhouse gases produces a climate signature different from that of warming due to solar radiation changes.

  12. Persistent spread in seasonal albedo change radiative forcings linked to forest cover changes at northern latitudes

    Science.gov (United States)

    Bright, R. M.; Myhre, G.; Astrup, R. A.; Antón-Fernández, C.; Strømman, A. H.

    2014-12-01

    Large-scale land use and land cover change (LULCC) can significantly affect regional climates from changes in surface biogeophysics, and a substantial part of historical LULCC from forest to crop or pasture occurred in the mid- and high-latitudes of North America and Eurasia where the snow-masking effect of forests often leads to a negative radiative forcing from albedo changes linked to deforestation. Results from several recent historical LULCC modeling studies, however, reveal an order of magnitude spread in climate forcing from the snow-masking effect by forests. This is likely because, in months with snow cover, the interactions between vegetation and snow significantly complicate the relationship between the change in forest cover fraction and albedo, thus accurate characterizations of land surface-albedo dynamics are essential given the importance of albedo feedbacks when ground or canopy surfaces are covered in snow Here, we evaluate snow masking parameterization schemes of seven prominent climate models in greater detail in order to pinpoint major sources of the persistent variability in albedo predictions across models. Using a comprehensive dataset of forest structure, meteorology, and daily MODIS albedo observations spanning three winter-spring seasons in three regions of boreal Norway, we estimate radiative forcings connected to canopy snow masking and compare it to the observed forcings. We develop a physically-based regression model and compare its performance to existing modeling schemes, concluding with a discussion on the utility of purely empirical parameterizations relative to those rooted in radiative transfer theory and/or process-based modeling.

  13. Rates of projected climate change dramatically exceed past rates of climatic niche evolution among vertebrate species.

    Science.gov (United States)

    Quintero, Ignacio; Wiens, John J

    2013-08-01

    A key question in predicting responses to anthropogenic climate change is: how quickly can species adapt to different climatic conditions? Here, we take a phylogenetic approach to this question. We use 17 time-calibrated phylogenies representing the major tetrapod clades (amphibians, birds, crocodilians, mammals, squamates, turtles) and climatic data from distributions of > 500 extant species. We estimate rates of change based on differences in climatic variables between sister species and estimated times of their splitting. We compare these rates to predicted rates of climate change from 2000 to 2100. Our results are striking: matching projected changes for 2100 would require rates of niche evolution that are > 10,000 times faster than rates typically observed among species, for most variables and clades. Despite many caveats, our results suggest that adaptation to projected changes in the next 100 years would require rates that are largely unprecedented based on observed rates among vertebrate species.

  14. 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…

  15. 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...

  16. Decrease in Suicide Rates after a Change of Policy Reducing Access to Firearms in Adolescents: A Naturalistic Epidemiological Study

    Science.gov (United States)

    Lubin, Gad; Werbeloff, Nomi; Halperin, Demian; Shmushkevitch, Mordechai; Weiser, Mark; Knobler, Haim Y.

    2010-01-01

    The use of firearms is a common means of suicide. We examined the effect of a policy change in the Israeli Defense Forces reducing adolescents' access to firearms on rates of suicide. Following the policy change, suicide rates decreased significantly by 40%. Most of this decrease was due to decrease in suicide using firearms over the weekend.…

  17. Decrease in Suicide Rates after a Change of Policy Reducing Access to Firearms in Adolescents: A Naturalistic Epidemiological Study

    Science.gov (United States)

    Lubin, Gad; Werbeloff, Nomi; Halperin, Demian; Shmushkevitch, Mordechai; Weiser, Mark; Knobler, Haim Y.

    2010-01-01

    The use of firearms is a common means of suicide. We examined the effect of a policy change in the Israeli Defense Forces reducing adolescents' access to firearms on rates of suicide. Following the policy change, suicide rates decreased significantly by 40%. Most of this decrease was due to decrease in suicide using firearms over the weekend.…

  18. 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.

  19. Precipitation Extremes: Considerations for Anthropogenically-forced Future Changes

    Science.gov (United States)

    Kunkel, K.; Young, J.

    2015-12-01

    The Third National Climate Assessment states that "increases in the frequency and intensity of extreme precipitation events are projected for all U.S. regions". While that general statement was made with high confidence, the practical implications for decision-makers are much less clear. In particular, engineering design needs quantitative estimates of probable maximum precipitation (PMP) and intensity-duration-frequency (IDF) values for the future in order to optimize runoff control structures for future climate conditions. This can be realized by simply analyzing the precipitation data from global climate model simulations of the future. However, confidence in the resulting values suffers from the known issues with GCM simulation of precipitation. In addition, skepticism about the accuracy of climate models negatively affects potential adoption of revised values in the engineering design community. We contend that scientists need a multi-pronged approach to develop PMP/IDF values that can be defended, explained, and promoted in order to maximize societal benefits and avoid catastrophic events. This talk will discuss considerations that could/should form the basis for design values. While global-warming induced increases in atmospheric water vapor content are nearly certain and form the foundation for expected increases in extreme precipitation, they most likely will be modulated by changes in global atmospheric dynamics and the consequent effects on local weather system climatology. This can be seen currently in the unexplained regional variations in recent trends in extreme precipitation frequency and intensity. We need to be able to understand recent trends, when greenhouse gas forcing of the climate systems has been rapidly increasing, in order to produce confident projections of future extreme precipitation.

  20. Polarization force-induced changes in the dust sheath formation

    Energy Technology Data Exchange (ETDEWEB)

    Mayout, Saliha; Bentabet, Karima; Tribeche, Mouloud [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Physics, University of Bab-Ezzouar, USTHB, BP 32, El Alia, Algiers 16111 (Algeria)

    2015-09-15

    The modifications arising in the dusty plasma sheath structure due to the presence of polarization forces acting on the dust grains are investigated. The corresponding appropriate Bohm criterion for sheath formation is obtained. It is found that the critical Mach number, beyond which the dusty plasma electrostatic sheath sets in, decreases whenever the polarization effects become important. In addition, when the polarization force dominates over the electrical one, the dust plasma sheath cannot set in. This happens whenever the dust grain size exceeds a critical threshold. Moreover, the sheath electrostatic potential-gradient becomes abruptly steep, and the sheath thickness becomes broader as the polarization force effects strengthen.

  1. Changes in Scottish suicide rates during the Second World War.

    OpenAIRE

    2006-01-01

    Abstract Background It is believed that total reported suicide rates tend to decrease during wartime. However, analysis of suicide rates during recent conflicts suggests a more complex picture, with increases in some age groups and changes in method choice. As few age and gender specific analyses of more distant conflicts have been conducted, it is not clear if these findings reflect a change in the epidemiology of suicide in wartime. Therefore, we examined suicide rates in Scotland before, d...

  2. Predicting domains and rates of change in borderline personality disorder.

    Science.gov (United States)

    Lenzenweger, Mark F; Clarkin, John F; Levy, Kenneth N; Yeomans, Frank E; Kernberg, Otto F

    2012-04-01

    What changes and how quickly these changes occur as a result of therapy in borderline personality disorder (BPD) is an important ongoing question. The features of BPD patients that are most predictive of rates of change in such patients remain largely unknown. Using the Cornell Personality Disorders Institute (CPDI) randomized controlled trial data, we sought to determine (a) the number and nature of broad domains underlying a large number of rate of change (slope) measures across many psychological, psychiatric, and psychosocial indexes, and (b) which baseline individual difference psychological features of the BPD patients correlated with these rate of change domains. We examined the latent structure of slope (rate of change) measures gleaned from individual growth curves for each subject, studied in multiwave perspective, on separate measures of anger, aggression, impulsivity, depression, global functioning, and social adjustment. Three broad domains of change rate could be discerned. These domains were reflected in factors that are described as (a) anger/aggression change ("aggressive dyscontrol"), (b) global functioning/social adjustment change ("social adjustment/self-acceptance"), and (c) anxiety/depression/impulsivity change ("conflict tolerance/behavioral control"). Factor scores were computed for each change domain and baseline measures of personality and psychodynamic features, selected a priori, were correlated with these factor scores. Multiple regression analyses revealed (a) baseline negative affectivity and aggression predicted the aggressive dyscontrol change domain, (b) baseline identity diffusion predicted the social adjustment/self-acceptance change domain, and (c) baseline social potency predicted the conflict tolerance/behavioral control change domain. These baseline predictors suggest potential research foci for understanding those aspects of BPD that change at comparable rates over time.

  3. Implementation of Organizational Change in the Air Force: a Case Study

    Science.gov (United States)

    1989-09-01

    ve) Lfl DTIC &’ELECTE IMPLEMENTATION OF ORGANIZATIONAL CHANGE IN THE AIR FORCE: A CASE STUDY THESIS Ronald D. Taylor First Lieutenant, USAF AFIT/GLM...022 AFIT/GLM/LSR/89S-66 IMPLEMENTATION OF ORGANIZATIONAL CHANGE IN THE AIR FORCE: A CASE STUDY THESIS Ronald D. Taylor First Lieutenant, USAF AFIT/GLM...Department of Defense. AFIT/GLM/LSR/89S-66 IMPLEMENTATION OF ORGANIZATIONAL CHANGE IN THE AIR FORCE: A CASE STUDY THESIS Presented to the Faculty of the

  4. 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

  5. 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.

  6. Changing the bonding force of impression tray to edentulous ...

    African Journals Online (AJOL)

    Key words: Bonding force, impression tray, maxillary jaw. Date of Acceptance: ... The purpose of complete dentures is to restore the dental and alveolar structures. ... A review of the literature revealed a lack of reports evaluating the pressure ...

  7. 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....

  8. 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.

  9. 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).

  10. Is transcription the dominant force during dynamic changes in gene expression?

    Science.gov (United States)

    Turner, Martin

    2011-01-01

    Dynamic changes in gene expression punctuate lymphocyte development and are a characteristic of lymphocyte activation. A prevailing view has been that these changes are driven by DNA transcription factors, which are the dominant force in gene expression. Accumulating evidence is challenging this DNA centric view and has highlighted the prevalence and dynamic nature of RNA handling mechanisms. Alternative splicing and differential polyadenylation appear to be more widespread than first thought. Changes in mRNA decay rates also affect the abundance of transcripts and this mechanism may contribute significantly to gene expression. Additional RNA handling mechanisms that control the intracellular localization of mRNA and association with translating ribosomes are also important. Thus, gene expression is regulated through the coordination of transcriptional and post-transcriptional mechanisms. Developing a more "RNA centric" view of gene expression will allow a more systematic understanding of how gene expression and cell function are integrated.

  11. Analysis of Conceptual Change and Status Change in Sixth-Graders Concepts of Force and Motion.

    Science.gov (United States)

    Hennessey, Mary Gertrude

    The Conceptual Change Model (CCM) was formulated over a decade ago to describe learning as a process in which an individuals change their conceptions by capturing new or exchanging existing conceptions for new ones. Central to the learning process is the status of the new and existing conceptions as seen by the learner. The CCM predicts that conceptual changes do not occur without corresponding changes in status. A review of the literature reveals that although the CCM has been extensively cited, the prediction of status change has not been investigated. This study sought to determine the feasibility of revealing and monitoring the status of sixth graders' conceptions of force and motion, and to probe the relationship between the revealed status of the students' conceptions and corresponding changes in the content of those. Status determination comes directly from the students' metaconceptual comments about the intelligibility, plausibility, and fruitfulness of their own conceptions. The study was conducted in three phases. In Phase I (7 weeks), the students learned the technical language of the CCM and established a consensus about a set of descriptors for each of the technical terms. Phase II (10 weeks), was a unit on force and motion, content not previously studied by the students. Data was gathered at key intervals, by having the students comment on both the content and status of selected force explanations. In Phase III (after a six week delay), further data about status and content was gathered. The analysis concluded that first, extensive and varied evidence exists of the students' ability to use the technical language reliable and with meaning. Second, when the students provide direct evidence of the status of their conceptions, status analysis becomes a low-inference task suitable for use in normal classrooms. Lastly, the data support the model's prediction of a correlation between conceptual exchange and changes in plausibility but do not support the

  12. Structural basis and kinetics of force-induced conformational changes of an αA domain-containing integrin.

    Directory of Open Access Journals (Sweden)

    Xue Xiang

    Full Text Available BACKGROUND: Integrin α(Lβ₂ (lymphocyte function-associated antigen, LFA-1 bears force upon binding to its ligand intercellular adhesion molecule 1 (ICAM-1 when a leukocyte adheres to vascular endothelium or an antigen presenting cell (APC during immune responses. The ligand binding propensity of LFA-1 is related to its conformations, which can be regulated by force. Three conformations of the LFA-1 αA domain, determined by the position of its α₇-helix, have been suggested to correspond to three different affinity states for ligand binding. METHODOLOGY/PRINCIPAL FINDINGS: The kinetics of the force-driven transitions between these conformations has not been defined and dynamically coupled to the force-dependent dissociation from ligand. Here we show, by steered molecular dynamics (SMD simulations, that the αA domain was successively transitioned through three distinct conformations upon pulling the C-terminus of its α₇-helix. Based on these sequential transitions, we have constructed a mathematical model to describe the coupling between the αA domain conformational changes of LFA-1 and its dissociation from ICAM-1 under force. Using this model to analyze the published data on the force-induced dissociation of single LFA-1/ICAM-1 bonds, we estimated the force-dependent kinetic rates of interstate transition from the short-lived to intermediate-lived and from intermediate-lived to long-lived states. Interestingly, force increased these transition rates; hence activation of LFA-1 was accelerated by pulling it via an engaged ICAM-1. CONCLUSIONS/SIGNIFICANCE: Our study defines the structural basis for mechanical regulation of the kinetics of LFA-1 αA domain conformational changes and relates these simulation results to experimental data of force-induced dissociation of single LFA-1/ICAM-1 bonds by a new mathematical model, thus provided detailed structural and kinetic characterizations for force-stabilization of LFA-1/ICAM-1 interaction.

  13. Near-Term Acceleration In The Rate of Temperature Change

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Steven J.; Edmonds, James A.; Hartin, Corinne A.; Mundra, Anupriya; Calvin, Katherine V.

    2015-03-09

    Anthropogenically-driven climate changes, which are expected to impact human and natural systems, are often expressed in terms of global-mean temperature . The rate of climate change over multi-decadal scales is also important, with faster rates of change resulting in less time for human and natural systems to adapt . We find that current trends in greenhouse gas and aerosol emissions are now moving the Earth system into a regime in terms of multi-decadal rates of change that are unprecedented for at least the last 1000 years. The rate of global-mean temperature increase in the CMIP5 archive over 40-year periods increases to 0.25±0.05 (1σ) °C per decade by 2020, an average greater than peak rates of change during the previous 1-2 millennia. Regional rates of change in Europe, North America and the Arctic are higher than the global average. Research on the impacts of such near-term rates of change is urgently needed.

  14. Data on force-dependent structural changes of chromatin fibers measured with magnetic tweezers

    Directory of Open Access Journals (Sweden)

    Fan-Tso Chien

    2014-12-01

    Full Text Available The compaction of chromatin fibers regulates the accessibility of embedded DNA, highly associated with transcriptional activities [1]. Single molecule force spectroscopy has revealed the great details of the structural changes of chromatin fibers in the presence of external exerted force [2–7]. However, most of the studies focus on a specific force regime [2,3,8,9]. The data here show force-extension (FE traces of chromatin fibers as measured with magnetic tweezers, covering the force regime from 0 pN to 27 pN. Those traces provide information for further studies at varied force regimes.

  15. Solar geoengineering to limit the rate of temperature change.

    Science.gov (United States)

    MacMartin, Douglas G; Caldeira, Ken; Keith, David W

    2014-12-28

    Solar geoengineering has been suggested as a tool that might reduce damage from anthropogenic climate change. Analysis often assumes that geoengineering would be used to maintain a constant global mean temperature. Under this scenario, geoengineering would be required either indefinitely (on societal time scales) or until atmospheric CO2 concentrations were sufficiently reduced. Impacts of climate change, however, are related to the rate of change as well as its magnitude. We thus describe an alternative scenario in which solar geoengineering is used only to constrain the rate of change of global mean temperature; this leads to a finite deployment period for any emissions pathway that stabilizes global mean temperature. The length of deployment and amount of geoengineering required depends on the emissions pathway and allowable rate of change, e.g. in our simulations, reducing the maximum approximately 0.3°C per decade rate of change in an RCP 4.5 pathway to 0.1°C per decade would require geoengineering for 160 years; under RCP 6.0, the required time nearly doubles. We demonstrate that feedback control can limit rates of change in a climate model. Finally, we note that a decision to terminate use of solar geoengineering does not automatically imply rapid temperature increases: feedback could be used to limit rates of change in a gradual phase-out.

  16. 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.

  17. Individual adaptation to experimental changes in running speed and step rate during treadmill running in injury-free runners

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Kjeldsen, Nikolaj Hørby; Stoklund Pedersen, Daniel

    2015-01-01

    extremity. These mechanisms are complex and the load in the individual joints is a result of the interaction between several parameters (4). The peak force however is important in evaluation of the all-overload of the lower extremity. Increased step rate during constant velocity has recently showed...... to result in decreased load of the knee and hip joints. However, based on clinical observations, most runners simultaneously changes the velocity when forced to change the step rate. The relation between reaction force, step rate and velocity is therefore explored in this multi-condition study...... treadmill and peak reaction force and temporal parameters were calculated as mean of respectively left and right side during the 30 seconds recording. All measurements were calculated as differences from values from running with self-selected velocity and step rate and the 5 conditions (90% and 110...

  18. Interdependence between Army Conventional Forces and Special Operations Forces: Changing Institutional Mental Models

    Science.gov (United States)

    2013-03-23

    JCO Joint Commission Observer JCOA Joint and Coalition Operational Analysis JP Joint Publication JTF Joint Task Force GCC Geographic...inherited from British predecessors, the Joint Commission Observer teams ( JCOs ) provided liaison, information exchange, and expedient communications...integration, the operational SOF JCOs were omnipresent throughout the area of responsibility. Their frequent interaction with CF units and leaders

  19. Fighters of the Total Force in the 21st Century: Should the Force Structure Change?

    Science.gov (United States)

    2001-04-01

    significant incentive, morale boost, and perk particularly for the enlisted force. This policy should be extended to unaccompanied personnel in Korea. If...82 MR-1306-RC, (2000). Available at: http://www.rand.org/publications/MR/MR1306/ Kirby, Sheila Nataraj, David Grissmer, Stephanie Williamson, and

  20. The big shift: measuring the forces of change

    DEFF Research Database (Denmark)

    Hagel, John; Brown, John Seely; Davison, Lang

    2009-01-01

    Traditional metrics don't capture many of the challenges and opportunities in store for U.S. companies and the national economy. The authors, from Deloitte, present a framework for understanding the forces that have transformed business over the past 40 years--and an index for gauging their impac...

  1. The big shift: measuring the forces of change

    DEFF Research Database (Denmark)

    Hagel, John; Brown, John Seely; Davison, Lang

    2009-01-01

    Traditional metrics don't capture many of the challenges and opportunities in store for U.S. companies and the national economy. The authors, from Deloitte, present a framework for understanding the forces that have transformed business over the past 40 years--and an index for gauging their impact...

  2. 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…

  3. Climate sensitivity and climate change under strong forcing

    Science.gov (United States)

    Boer, G. J.; Hamilton, K.; Zhu, W.

    2005-06-01

    A version of the National Centre for Atmospheric Research (NCAR) coupled climate model is integrated under current climate conditions and in a series of experiments with climate forcings ranging from modest to very strong. The purpose of the experiments is to investigate the nature and behaviour of the climate feedback/sensitivity of the model, its evolution with time and climate state, the robustness of model parameterizations as forcing levels increase, and the possibility of a “runaway” warming under strong forcing. The model is integrated for 50 years, or to failure, after increasing the solar constant by 2.5, 10, 15, 25, 35, and 45% of its control value. The model successfully completes 50 years of integration for the 2.5, 10, 15, and 25% solar constant increases but fails for increases of 35% and 45%. The effective global climate sensitivity evolves with time and analysis indicates that a new equilibrium will be obtained for the 2.5, 10, and 15% cases but that runaway warming is underway for the 25% increase in solar constant. Feedback processes are analysed both locally and globally in terms of longwave and shortwave, clear-sky/surface, and cloud forcing components. Feedbacks in the system must be negative overall and of sufficient strength to balance the positive forcing if the system is to attain a new equilibrium. Longwave negative feedback processes strengthen in a reasonably linear fashion as temperature increases but shortwave feedback processes do not. In particular, solar cloud feedback becomes less negative and, for the 25% forcing case, eventually becomes positive, resulting in temperatures that “run away”. The conditions under which a runaway climate warming might occur have previously been investigated using simpler models. For sufficiently strong forcing, the greenhouse effect of increasing water vapour in a warmer atmosphere is expected to overwhelm the negative feedback of the longwave cooling to space as temperature increases. This is

  4. What determines the rate of growth and technological change?

    OpenAIRE

    ROMER, Paul M.

    1989-01-01

    There is substantial research about cross section and time series correlations between economic growth and various economic, social, demographic and political variables. After analyzing these correlations, the paper makes the following conclusions. Exogenous increases do not seem to cause increases in the rate of technological change, but instead seem to be associated with lower rates of return to capital. Increased openness to international trade speeds up growth and technological change as ...

  5. The driving forces of land change in the Northern Piedmont of the United States

    Science.gov (United States)

    Auch, Roger F.; Napton, Darrell E.; Kambly, Steven; Moreland, Thomas R.; Sayler, Kristi L.

    2012-01-01

    Driving forces facilitate or inhibit land-use/land-cover change. Human driving forces include political, economic, cultural, and social attributes that often change across time and space. Remotely sensed imagery provides regional land-change data for the Northern Piedmont, an ecoregion of the United States that continued to urbanize after 1970 through conversion of agricultural and forest land covers to developed uses. Eight major driving forces facilitated most of the land conversion; other drivers inhibited or slowed change. A synergistic web of drivers may be more important in understanding land change than individual drivers by themselves.

  6. Revisiting Asian monsoon formation and change associated with Tibetan Plateau forcing: II. Change

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yimin; Wu, Guoxiong; Duan, Anmin; Bao, Qing [Chinese Academy of Sciences, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Beijing (China); Hong, Jieli; Zhou, Linjiong [Chinese Academy of Sciences, State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Beijing (China); Graduate University of Chinese Academy of Sciences, Beijing (China); Dong, Buwen [University of Reading, Department of Meteorology, National Centre for Atmospheric Science, Reading (United Kingdom)

    2012-09-15

    Data analysis based on station observations reveals that many meteorological variables averaged over the Tibetan Plateau (TP) are closely correlated, and their trends during the past decades are well correlated with the rainfall trend of the Asian summer monsoon. However, such correlation does not necessarily imply causality. Further diagnosis confirms the existence of a weakening trend in TP thermal forcing, characterized by weakened surface sensible heat flux in spring and summer during the past decades. This weakening trend is associated with decreasing summer precipitation over northern South Asia and North China and increasing precipitation over northwestern China, South China, and Korea. An atmospheric general circulation model, the HadAM3, is employed to elucidate the causality between the weakening TP forcing and the change in the Asian summer monsoon rainfall. Results demonstrate that a weakening in surface sensible heating over the TP results in reduced summer precipitation in the plateau region and a reduction in the associated latent heat release in summer. These changes in turn result in the weakening of the near-surface cyclonic circulation surrounding the plateau and the subtropical anticyclone over the subtropical western North Pacific, similar to the results obtained from the idealized TP experiment in Part I of this study. The southerly that normally dominates East Asia, ranging from the South China Sea to North China, weakens, resulting in a weaker equilibrated Sverdrup balance between positive vorticity generation and latent heat release. Consequently, the convergence of water vapor transport is confined to South China, forming a unique anomaly pattern in monsoon rainfall, the so-called ''south wet and north dry.'' Because the weakening trend in TP thermal forcing is associated with global warming, the present results provide an effective means for assessing projections of regional climate over Asia in the context of global

  7. 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.

  8. Analysis of changes in paper cutting forces during the cutting cycle in single-knife guillotine

    OpenAIRE

    Rusin, Agnieszka; Petriaszwili, Georgij

    2013-01-01

    Paper presents the results of changes in the three components of cutting forces of paper stacks cutting during the cutting cycle in single-knife guillotine. The changes of the three components of cutting force at different stages of cutting cycle were analyzed.

  9. USMC Contingency Contracting Force: An Analysis of Transient Officers in a Rapidly Changing Acquisition Environment

    Science.gov (United States)

    2016-06-01

    due to the highly technical and frequently changing regulations that govern contracting operations. Figure 2. Question 2 Survey Response Chart ...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA JOINT APPLIED PROJECT USMC CONTINGENCY CONTRACTING FORCE: AN ANALYSIS OF...CONTINGENCY CONTRACTING FORCE: AN ANALYSIS OF TRANSIENT OFFICERS IN A RAPIDLY CHANGING ACQUISITION ENVIRONMENT 5. FUNDING NUMBERS 6. AUTHOR(S) Adam

  10. 18 CFR 154.313 - Schedules for minor rate changes.

    Science.gov (United States)

    2010-04-01

    ... rate changes. 154.313 Section 154.313 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER NATURAL GAS ACT RATE SCHEDULES AND TARIFFS... component (e.g., reservation charges, demand charges, usage charges, commodity charges, injection...

  11. 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.

  12. 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...

  13. Indirect effect of changing aerosol concentrations on methane and ozone radiative forcing

    Science.gov (United States)

    Rowlinson, Matthew; Rap, Alexandru; Arnold, Steve; Forster, Piers; Chipperfield, Martyn

    2017-04-01

    Atmospheric aerosols interact with climate in number of complex ways and quantifying the overall effect remains the dominant uncertainty in estimating anthropogenic climate forcing (IPCC, 2013). The radiative forcing (RF) caused by the direct effect of aerosol interacting with radiation is estimated at -0.35 (-0.85 to +0.15) Wm-2, while cloud-aerosol interactions are estimated at -0.45 (-1.2 to 0.0) Wm-2 (IPCC, 2013). The net impact is a cooling with an effective radiative forcing (ERF) of 0.9 (-1.9 to -0.1) Wm-2 (IPCC, 2013). One effect of aerosols which has not been well evaluated is their effect on atmospheric chemistry. Atmospheric aerosols provide a surface for homogeneous reactions to occur, altering reactions rates and the availability of oxidants, thereby influencing the removal/production of radiatively important species such as methane (CH4) and tropospheric ozone (O3). Oxidants such as the hydroxyl radical (OH) determine the atmospheric lifetime and hence burden of CH4, therefore changes to atmospheric aerosols which impact oxidation chemistry will also influence RF due to CH4. This effect could enhance or offset the negative RF of aerosols, depending on how the individual aerosol changes availability of oxidants. Quantifying the importance of this mechanism for RF is necessary to provide accurate estimates of the effect of aerosols, and assess relative effectiveness of measures to decrease aerosol emissions and precursors. Using a sophisticated aerosol micro-physics model (GLOMAP) coupled to the TOMCAT three-dimensional chemical transport model, we separately simulate changes in atmospheric composition resulting from a 50% decline in anthropogenic emissions of black carbon aerosol (BC), volatile organic compounds (VOCs) and anthropogenic precursors of sulphate and nitrate. The impact of changes to each aerosol on lifetime of CH4 is then calculated to establish the resulting impact on CH4 burden and RF. Cutting global anthropogenic SO2 emissions by 50

  14. DYNAMIC CHANGES OF THE WETLAND AND ITS DRIVING FORCES IN FUJIN REGION IN SANJIANG PLAIN, CHINA

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-Qiang; CHEN Ming; WANG Dan-Dan; ZHANG Bai; ZHANG Shu-Qing

    2005-01-01

    Wetland is a kind of key natural resources. However, the wetlands have been shrinking rapidly in Sangjiang Plain and its functions have been degrading. These all hold back the sustainable development of human communities, and lead to great change in the land use /cover (LUCC), consequently caused global changes in climate, water cycling, etc.. Taken Fujin region as a case study, spatial and temporal dynamic processes of wetland and its driving forces were analyzed from 1954 to 2000 in this paper. It showed that the wetlands had been reduced from 52×104 ha to 11×104 ha in areas during the nearly 50 years . The percentage of wetland areas reduced from 61.27% to 12.39%. On the other hand, cultivated land increased from 22×104 ha to 60×104 ha in areas. The percentage of the areas increased from 25.31% to 70.45%. Further quantitative analysis of the wetland landscape conversion characteristics and the correlation analysis between the change of wetland areas and population increase were made. The results showed that 40×104 ha wetlands had been converted to cultivated land within half of a century; the correlation between the rate of wetland loss and that of population increased is nearly -0.922. So it was concluded that the main driving force of wetland shrinkage in Fujin region was the colonization of human being.

  15. 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.

  16. 77 FR 72960 - International Mail: Product Rate and Fee Changes

    Science.gov (United States)

    2012-12-07

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE 39 CFR Part 20 International Mail: Product Rate and Fee Changes AGENCY: Postal Service TM . ACTION: Final rule... United States Postal Service, International Mail Manual (IMM ). The proposed rule included changes that...

  17. A Modeling Perspective on Interpreting Rates of Change in Context

    Science.gov (United States)

    Ärlebäck, Jonas B.; Doerr, Helen M.; O'Neil, AnnMarie H.

    2013-01-01

    Functions provide powerful tools for describing change, but research has shown that students find difficulty in using functions to create and interpret models of changing phenomena. In this study, we drew on a models and modeling perspective to design an instructional approach to develop students' abilities to describe and interpret rates of…

  18. 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.

  19. Predator Force Structure Changes at Indian Springs Air Force Auxiliary Field, Nevada Environmental Assessment

    Science.gov (United States)

    2003-07-01

    the North Las Vegas Library (Main Branch), the Indian Springs Library, and online at www.cevp.com and www.nellis.af.mil. A Notice of Availability...USGS (U.S. Geological Survey). 2001. Online Table of Seismic Hazards. http://geohazards.cr.usgs.gov/eq/faults/fsrpage11.html Predator Force...Sincerely, __ ~~~-~ Heather K. Elliott Nevada State Clearinghouse/ SPOC NEVADA STATE CLEARINGHOUSE Department of Administration Budget and Planning

  20. 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.

  1. 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.

  2. How do salt-marsh ecosystems respond to changes in the environmental forcings?

    Science.gov (United States)

    D'Alpaos, A.; Mudd, S. M.; Carniello, L.

    2012-04-01

    How do salt-marsh ecosystems respond to changes in the environmental forcings? This is a question of paramount importance due to the critical role exerted by salt-marsh ecosystems within the tidal landscape. Salt marshes in fact buffer coastlines against, filter nutrients and pollutants from tidal waters, provide nursery areas for coastal biota, and serve as a sink for organic carbon. Observations of marsh degradation worldwide and the acceleration in the rate of global sea level rise highlight the importance of improving our understanding of the chief processes controlling salt-marsh response to current natural climate changes and to the effects of changes in sediment supply. To address this important issue, we have applied a analytical model of biomorphodynamic evolution of salt-marsh ecosystems in the vertical plane, accounting for two-way interactions between ecological and geomorphological processes. Our results show that marshes are more resilient to a step decrease in the rate of relative sea level rise (RRSLR) rather than to a step increase of the same magnitude. However, marshes respond more rapidly to an increase in sediment load or vegetation productivity, rather than to a decrease (of the same amount) in sediment load or vegetation productivity. We also observe that marsh stability is therefore positively correlated with tidal range: marshes with high tidal ranges respond more slowly to changes in the environmental forcings and therefore are less likely to be affected by perturbations. Finally, the model suggests that, in the case of a oscillating RRSLR, marsh stratigraphy will be unable to fully record short-term fluctuations in relative mean sea level, whereas it will be able to capture long-term fluctuations particularly in sediment rich, microtidal settings.

  3. Swiss Armed Forces Conscription and Militia System: Must They Change?

    Science.gov (United States)

    2013-12-13

    capacities must assume public duties and consequences in an extra professional and volunteer capacity. This expression specific to Switzerland is...by a solid link of trust. The author makes a side note that conscription is lucky, when it comes to pedagogy and relations in the Swiss society. In...Forces. Personal engagement, non- professional and time limited made by male and female citizens in order to accomplish public tasks allotted to the

  4. CHANGE@CERN:Task Force 5 : Restructuring the accelerator sector

    CERN Document Server

    2002-01-01

    The last of our series on the Task Forces. PS accelerator 'We had a clear mandate, which we could approach in a logical way', explains Steve Myers, Head of SL Division and convenor of Task Force 5, 'To avoid duplication of effort in the accelerator sector through a restructuring that would lead to greater efficiency and flexibility and so release resources for the LHC.' The implementation of all their recommendations is already underway, albeit with different time scales. In 2001 the accelerator sector involved more than 900 staff members in three divisions (LHC, PS and SL) and one unit (AC), working in 141 sections within 34 groups. The first step for the Task Force was to identify major activities within the sector and to set up inter-divisional working groups to review these activities (16 in all), identifying the technologies and the numbers of staff associated with each activity. The working groups were also asked to propose ways of grouping the activities into a new more efficient organizational stru...

  5. Maximal force and tremor changes across the menstrual cycle.

    Science.gov (United States)

    Tenan, Matthew S; Hackney, Anthony C; Griffin, Lisa

    2016-01-01

    Sex hormones have profound effects on the nervous system in vitro and in vivo. The present study examines the effect of the menstrual cycle on maximal isometric force (MVC) and tremor during an endurance task. Nine eumenorrheic females participated in five study visits across their menstrual cycle. In each menstrual phase, an MVC and an endurance task to failure were performed. Tremor across the endurance task was quantified as the coefficient of variation in force and was assessed in absolute time and relative percent time to task failure. MVC decreases 23% from ovulation to the mid luteal phase of the menstrual cycle. In absolute time, the mid luteal phase has the highest initial tremor, though the early follicular phase has substantially higher tremor than other phases after 150 s of task performance. In relative time, the mid luteal phase has the highest level of tremor throughout the endurance task. Both MVC and tremor during an endurance task are modified by the menstrual cycle. Performance of tasks and sports which require high force and steadiness to exhaustion may be decreased in the mid luteal phase compared to other menstrual phases.

  6. 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.

  7. Measuring stall forces in vivo with optical tweezers through light momentum changes

    Science.gov (United States)

    Mas, J.; Farré, A.; López-Quesada, C.; Fernández, X.; Martín-Badosa, E.; Montes-Usategui, M.

    2011-10-01

    The stall forces of processive molecular motors have been widely studied previously in vitro. Even so, in vivo experiments are required for determining the actual performance of each molecular motor in its natural environment. We report the direct measurement of light momentum changes in single beam optical tweezers as a suitable technique for measuring forces inside living cells, where few alternatives exist. The simplicity of this method, which does not require force calibration for each trapped object, makes it convenient for measuring the forces involved in fast dynamic biological processes such us intracellular traffic. Here we present some measurements of the stall force of processive molecular motors inside living Allium cepa cells.

  8. Making Sense of Rate of Change: Secondary Students' Reasoning about Changing Quantities

    Science.gov (United States)

    Johnson, Heather L.

    2010-01-01

    Rate of change is an important concept for students to study, and little is known about the ways in which secondary students make sense of rate of change. In this qualitative study I examined how four high school students who have not taken calculus reasoned about changing quantities when interacting with mathematical tasks involving multiple…

  9. 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

  10. Evolving Shoreline Change Rates Along the US Pacific Northwest Coast

    Science.gov (United States)

    Anderson, D. L.; Ruggiero, P.; Allan, J. C.

    2013-12-01

    Coastal change hazards are increasingly affecting economically important areas, including those used for infrastructure, commerce, and public recreation. Quantifying shoreline change rates and understanding the contributing factors is crucial to protect these areas and to assist federal, state, and local agencies in developing long-term management plans. A recent study by the USGS National Assessment of Shoreline Change project analyzed the historical shoreline record along the U.S. Pacific Northwest with emphasis on both century-scale (1800s--2002) and decadal-scale (1960-80s--2002) change rates (Ruggiero, P., Kratzmann, M.A., Himmelstoss, E.G., Reid, D., Allan, J., and Kaminsky, G., 2013: U.S. Geological Survey Open-File Report 2012-1007, 55 p.). The study was the first consistent state-wide coastal change assessment for Oregon and revealed a significant increase in erosion hazards in the near-term. The coastal landscape in Oregon is particularly dynamic and includes beaches that are backed by both cliffs and dunes, and range in texture from sand to cobble. The high wave energy in the Pacific Northwest results in a morphology with primarily intermediate to dissipative beaches. Resistant rocky headlands separate the Oregon coast into 18 distinct littoral cells, greatly influencing how the shoreline changes with time. While the century-scale average of all 560 km of Oregon coastline suggests the shore is prograding at 0.4 m/yr, the decadal-scale record indicates that 13 of the 18 littoral cells either are accreting at a slower rate, have changed from accretional to erosional, or are eroding at a faster rate. This apparent increase in erosion-affected coasts may be caused by several factors including sea-level rise, increasing storm wave heights, tectonic uplift, and climatic events (eg., El Niño), but overall it indicates a shifting trend in shoreline change rates. In the present study, we quantify shoreline change rates on a third timescale, seasonal to

  11. Proactive changes in nursing work force development in Tennessee.

    Science.gov (United States)

    Moody, N B; Smith, P L

    1997-12-01

    Problems to be addressed by the CIC grant have been identified and defined, and a coalition has been formalized to address nursing work force development in Tennessee. The THCN, composed of consumers, nursing educators, policy makers, healthcare providers, and representatives of professional organizations and regulatory boards, is enthusiastically tackling the implementation phase of the project. These members are demonstrating open communication, teamwork, and interdependent decision making. Results are being achieved through persuasion, negotiation, seeking input from others, showing political sensitivity, and a willingness to share rewards and recognition.

  12. Planning for Climate Change: What Should the Air Force Do

    Science.gov (United States)

    2011-06-26

    data and research to the contrary, the cynics of climate change should be considered statistical outliers . The following are 10 select summary...adapt to climate change, mitigate its impacts, conserve forests , and invest in clean energy technologies. We will pursue this global cooperation...with climate change and spent our time and money elsewhere. 2- Noah’s Ark. Maybe we should have listened to that flood insurance salesman

  13. 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.

  14. 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.

  15. Rate of conditioned reinforcement affects observing rate but not resistance to change.

    Science.gov (United States)

    Shahan, Timothy A; Podlesnik, Christopher A

    2005-07-01

    The effects of rate of conditioned reinforcement on the resistance to change of operant behavior have not been examined. In addition, the effects of rate of conditioned reinforcement on the rate of observing have not been adequately examined. In two experiments, a multiple schedule of observing-response procedures was used to examine the effects of rate of conditioned reinforcement on observing rates and resistance to change. In a rich component, observing responses produced a higher frequency of stimuli correlated with alternating periods of random-interval schedule primary reinforcement or extinction. In a lean component, observing responses produced similar schedule-correlated stimuli but at a lower frequency. The rate of primary reinforcement in both components was the same. In Experiment 1, a 4:1 ratio of stimulus production was arranged by the rich and lean components. In Experiment 2, the ratio of stimulus production rates was increased to 6:1. In both experiments, observing rates were higher in the rich component than in the lean component. Disruptions in observing produced by presession feeding, extinction of observing responses, and response-independent food deliveries during intercomponent intervals usually were similar in the rich and lean components. When differences in resistance to change did occur, observing tended to be more resistant to change in the lean component. If resistance to change is accepted as a more appropriate measure of response strength than absolute response rates, then the present results provide no evidence that higher rates of stimuli generally considered to function as conditioned reinforcers engender greater response strength.

  16. Albedo changes, Milankovitch forcing, and late quaternary climate changes in the central Andes

    Energy Technology Data Exchange (ETDEWEB)

    Kull, C.; Grosjean, M. [Swiss Federal Inst. of Tech., Zurich (Switzerland). Dept. of Geography

    1998-11-01

    Late quaternary humidity changes resulted in substantial modifications of the land surface characteristics in the Altiplano of the Atacama desert, central Andes. Reconstructions of surface albedo, top-of-atmosphere (TOA) albedo, and shortwave net radiation in the Andes of northern Chile for 20,14,10,7 and 0 ka suggest that surface and TOA albedo increased substantially during periods of relatively humid environmental conditions (i.e., with large palaeolakes, glaciers and dense vegetation). The decrease of summer shortwave net radiation and seasonality during the late-glacial/early Holocene humid phase (14 to 10 ka) due to Earth`s surface and atmospheric characteristics added to the effect of orbitally driven negative deviations of southern Hemisphere austral summer insolation and minimum seasonality at 20 S. Therefore, in situ radiative forcing is, in contrast to the Northern Hemisphere tropics, not a suitable explanation for enhanced convective precipitation and, ultimately, humid climatic conditions. Our results suggest that late Quaternary humidity changes on the Altiplano reflect a collective response to (1) environmental changes in the source area of the moisture (e.g., reexpansion of the rain forest and increased release of latent heat over Amazonia and the Chaco, warm sea surface temperatures in the E Pacific) and, (2) large-scale circulation patterns and wave structures in the upper troposphere (strength and position of the Bolivian high, divergent flow stimulating convection over the Altiplano), or that they even reflect a response to (3) interhemispherical teleconnections. (orig.) With 5 figs., 2 tabs., 45 refs.

  17. 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

  18. 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.

  19. Social and Governance Changes: Rate, Principles, and Morals

    Directory of Open Access Journals (Sweden)

    Massimo N. Nardo

    2014-09-01

    Full Text Available This paper draws attention to two aspects of change; first, the rate of social change is a source of concern, to this is added that both the configuration of changes and the values dimension, add to those concerns. Change makes it hard to keep up, and is the generator of much stress. We need to apprehend that such a point applies strongly to all enterprises, in particular to governance issues. This article holds that the rate of change is compounded by a constantly changing configuration. To ameliorate those concerns it is held that there needs to be both an expression of agreed basic principles, and recognition that values are one of the most vital parts of that selection. In this the debate and explication of guiding principles, particularly in governance, that is crucial. The main point here is to again emphasise the complexity that results not only from the rate of change but also the configuration and moral values that it constantly tests. It is only by direct consideration that concern over such issues be reduced. It is also held that an explication of basic principles is a significant aid to coping with the source of such stress.

  20. Estimation of changes in dynamic hydraulic force in a magnetically suspended centrifugal blood pump with transient computational fluid dynamics analysis.

    Science.gov (United States)

    Masuzawa, Toru; Ohta, Akiko; Tanaka, Nobuatu; Qian, Yi; Tsukiya, Tomonori

    2009-01-01

    The effect of the hydraulic force on magnetically levitated (maglev) pumps should be studied carefully to improve the suspension performance and the reliability of the pumps. A maglev centrifugal pump, developed at Ibaraki University, was modeled with 926 376 hexahedral elements for computational fluid dynamics (CFD) analyses. The pump has a fully open six-vane impeller with a diameter of 72.5 mm. A self-bearing motor suspends the impeller in the radial direction. The maximum pressure head and flow rate were 250 mmHg and 14 l/min, respectively. First, a steady-state analysis was performed using commercial code STAR-CD to confirm the model's suitability by comparing the results with the real pump performance. Second, transient analysis was performed to estimate the hydraulic force on the levitated impeller. The impeller was rotated in steps of 1 degrees using a sliding mesh. The force around the impeller was integrated at every step. The transient analysis revealed that the direction of the radial force changed dynamically as the vane's position changed relative to the outlet port during one circulation, and the magnitude of this force was about 1 N. The current maglev pump has sufficient performance to counteract this hydraulic force. Transient CFD analysis is not only useful for observing dynamic flow conditions in a centrifugal pump but is also effective for obtaining information about the levitation dynamics of a maglev pump.

  1. Rate of Period Change as a Diagnostic of Cepheid Properties

    CERN Document Server

    Turner, D G; Berdnikov, L N

    2006-01-01

    Rate of period change $\\dot{P}$ for a Cepheid is shown to be a parameter that is capable of indicating the instability strip crossing mode for individual objects, and, in conjunction with light amplitude, likely location within the instability strip. Observed rates of period change in over 200 Milky Way Cepheids are demonstrated to be in general agreement with predictions from stellar evolutionary models, although the sample also displays features that are inconsistent with some published models and indicative of the importance of additional factors not fully incorporated in models to date.

  2. Forest management could counteract distribution retractions forced by climate change.

    Science.gov (United States)

    Mair, Louise; Harrison, Philip J; Räty, Minna; Bärring, Lars; Strandberg, Gustav; Snäll, Tord

    2017-03-28

    Climate change is expected to drive the distribution retraction of northern species. However, particularly in regions with a history of intensive exploitation, changes in habitat management could facilitate distribution expansions counter to expectations under climate change. Here, we test the potential for future forest management to facilitate the southwards expansion of an old-forest species from the boreal region into the boreo-nemoral region, contrary to expectations under climate change. We used an ensemble of species distribution models based on citizen science data to project the response of Phellinus ferrugineofuscus, a red-listed old-growth indicator, wood-decaying fungus, to six forest management and climate change scenarios. We projected change in habitat suitability across the boreal and boreo-nemoral regions of Sweden for the period 2020-2100. Scenarios varied in the proportion of forest set-aside from production, the level of timber extraction, and the magnitude of climate change. Habitat suitabilities for the study species were projected to show larger relative increases over time in the boreo-nemoral region compared to the boreal region, under all scenarios. By 2100, mean suitabilities in set-aside forest in the boreo-nemoral region were similar to the suitabilities projected for set-aside forest in the boreal region in 2020, suggesting that occurrence in the boreo-nemoral region could be increased. However, across all scenarios, consistently higher projected suitabilities in set-aside forest in the boreal region indicated that the boreal region remained the species stronghold. Furthermore, negative effects of climate change were evident in the boreal region, and projections suggested that climatic changes may eventually counteract the positive effects of forest management in the boreo-nemoral region. Our results suggest that the current rarity of this old-growth indicator species in the boreo-nemoral region may be due to the history of intensive

  3. Partitioning changes in photosynthetic rate into contributions from different variables.

    Science.gov (United States)

    Buckley, Thomas N; Diaz-Espejo, Antonio

    2015-06-01

    Changes in net CO2 assimilation rate (A) are often partitioned into contributions from changes in different variables using an approach that is based on an expression from calculus: namely the definition of the exact differential of A, which states that an infinitesimal change in A (dA) is equal to the sum of infinitesimal changes in each of the underlying variables, each multiplied by the partial derivative of A with respect to the variable. Finite changes in A can thus be partitioned by integrating this sum across a finite interval. The most widely used method of estimating that integral is a coarse discrete approximation that uses partial derivatives of the natural logarithm of A rather than A itself. This yields biased and ambiguous estimates of partitioned changes in A. We present an alternative partitioning approach based on direct numerical integration of dA. The new approach does not require any partial derivatives to be computed, and it can be applied under any conditions to estimate the contributions from changes in any photosynthetic variable. We demonstrate this approach using field measurements of both seasonal and diurnal changes in assimilation rate, and we provide a spreadsheet implementing the new approach.

  4. Conventional forces and arms control: Technology and strategy in a changing world

    Energy Technology Data Exchange (ETDEWEB)

    Pilat, J.F.; White, P.C.

    1990-06-01

    To address the implications of changes for future roles of conventional forces and to assess the technology implications of future strategies, force requirements, and conventional arms control agreements, the Center for National Security Studies in cooperation with the Defense Research and Applications Directorate of the Los Alamos National Laboratory held a conference on Conventional Forces and Arms Control: Technology and Strategy in a Changing World'' at Los Alamos from September 25--27, 1989. The distinguished participants from government, industry, and academia in the United States and Western Europe addressed such issues as: What are the implications of geopolitical and technological trends for international security and stability How will these global changes affect US and allied strategies and force structure, especially the requirements for conventional, nonnuclear forces What will be the role of and rationale for conventional forces in the context of current and prospective allied security requirements How can the West assure it will have the forces necessary for its security How will technological developments influence the structure of tomorrow's conventional forces What impacts will arms reductions have on future systems and force structures What are the prospects for the development and deployment in weapon systems of future conventional military technologies, in light of existing and potential political, economic, bureaucratic, and other impediments

  5. 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).

  6. 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.

  7. 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.

  8. The evolutionary rate dynamically tracks changes in HIV-1 epidemics

    Energy Technology Data Exchange (ETDEWEB)

    Maljkovic-berry, Irina [Los Alamos National Laboratory; Athreya, Gayathri [Los Alamos National Laboratory; Daniels, Marcus [Los Alamos National Laboratory; Bruno, William [Los Alamos National Laboratory; Korber, Bette [Los Alamos National Laboratory; Kuiken, Carla [Los Alamos National Laboratory; Ribeiro, Ruy M [Los Alamos National Laboratory

    2009-01-01

    Large-sequence datasets provide an opportunity to investigate the dynamics of pathogen epidemics. Thus, a fast method to estimate the evolutionary rate from large and numerous phylogenetic trees becomes necessary. Based on minimizing tip height variances, we optimize the root in a given phylogenetic tree to estimate the most homogenous evolutionary rate between samples from at least two different time points. Simulations showed that the method had no bias in the estimation of evolutionary rates and that it was robust to tree rooting and topological errors. We show that the evolutionary rates of HIV-1 subtype B and C epidemics have changed over time, with the rate of evolution inversely correlated to the rate of virus spread. For subtype B, the evolutionary rate slowed down and tracked the start of the HAART era in 1996. Subtype C in Ethiopia showed an increase in the evolutionary rate when the prevalence increase markedly slowed down in 1995. Thus, we show that the evolutionary rate of HIV-1 on the population level dynamically tracks epidemic events.

  9. 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.

  10. Force Responses and Sarcomere Dynamics of Cardiac Myofibrils Induced by Rapid Changes in [Pi].

    Science.gov (United States)

    Stehle, Robert

    2017-01-24

    The second phase of the biphasic force decay upon release of phosphate from caged phosphate was previously interpreted as a signature of kinetics of the force-generating step in the cross-bridge cycle. To test this hypothesis without using caged compounds, force responses and individual sarcomere dynamics upon rapid increases or decreases in concentration of inorganic phosphate [Pi] were investigated in calcium-activated cardiac myofibrils. Rapid increases in [Pi] induced a biphasic force decay with an initial slow decline (phase 1) and a subsequent 3-5-fold faster major decay (phase 2). Phase 2 started with the distinct elongation of a single sarcomere, the so-called sarcomere "give". "Give" then propagated from sarcomere to sarcomere along the myofibril. Propagation speed and rate constant of phase 2 (k+Pi(2)) had a similar [Pi]-dependence, indicating that the kinetics of the major force decay (phase 2) upon rapid increase in [Pi] is determined by sarcomere dynamics. In contrast, no "give" was observed during phase 1 after rapid [Pi]-increase (rate constant k+Pi(1)) and during the single-exponential force rise (rate constant k-Pi) after rapid [Pi]-decrease. The values of k+Pi(1) and k-Pi were similar to the rate constant of mechanically induced force redevelopment (kTR) and Ca(2+)-induced force development (kACT) measured at same [Pi]. These results indicate that the major phase 2 of force decay upon a Pi-jump does not reflect kinetics of the force-generating step but results from sarcomere "give". The other phases of Pi-induced force kinetics that occur in the absence of "give" yield the same information as mechanically and Ca(2+)-induced force kinetics (k+Pi(1) ∼ k-Pi ∼ kTR ∼ kACT). Model simulations indicate that Pi-induced force kinetics neither enable the separation of Pi-release from the rate-limiting transition f into force states nor differentiate whether the "force-generating step" occurs before, along, or after the Pi-release.

  11. 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.

  12. Reasoning about Variation in the Intensity of Change in Covarying Quantities Involved in Rate of Change

    Science.gov (United States)

    Johnson, Heather L.

    2012-01-01

    This paper extends work in the area of quantitative reasoning related to rate of change by investigating numerical and nonnumerical reasoning about covarying quantities involved in rate of change via tasks involving multiple representations of covarying quantities. The findings suggest that by systematically varying one quantity, an individual…

  13. Together yet Separate: Students' Associating Amounts of Change in Quantities Involved in Rate of Change

    Science.gov (United States)

    Johnson, Heather L.

    2015-01-01

    This paper extends work about quantitative reasoning related to covarying quantities involved in rate of change. It reports a multiple case study of three students' reasoning about quantities involved in rate of change when working on tasks incorporating multiple representations of covarying quantities. When interpreting relationships between…

  14. Reasoning about Variation in the Intensity of Change in Covarying Quantities Involved in Rate of Change

    Science.gov (United States)

    Johnson, Heather L.

    2012-01-01

    This paper extends work in the area of quantitative reasoning related to rate of change by investigating numerical and nonnumerical reasoning about covarying quantities involved in rate of change via tasks involving multiple representations of covarying quantities. The findings suggest that by systematically varying one quantity, an individual…

  15. Spatial-Temporal Pattern and Driving Forces of Land Use Changes in Xiamen

    Institute of Scientific and Technical Information of China (English)

    QUAN Bin; CHEN Jian-Fei; QIU Hong-Lie; M.J.M.R(O)MKENS; YANG Xiao-Qi; JIANG Shi-Feng; LI Bi-Cheng

    2006-01-01

    Using Landsat TM data of 1988, 1998 and 2001, the dynamic process of the spatial-temporal characteristics of land use changes during 13 years from 1988 to 2001 in the special economic zone of Xiamen, China was analyzed to improve understanding and to find the driving forces of land use change so that sustainable land utilization could be practiced.During the 13 years cropland decreased remarkably by nearly 11304.95 ha. The areas of rural-urban construction and water body increased by 10152.24 ha and 848.94 ha, respectively. From 1988 to 2001, 52.5% of the lost cropland was converted into rural-urban industrial land. Rapid urbanization contributed to a great change in the rate of cropland land use during these years. Land-reclamation also contributed to a decrease in water body area as well as marine ecological and environmental destruction. In the study area 1) urbanization and industrialization, 2) infrastructure and agricultural intensification, 3) increased affluence of the farming community, and 4) policy factors have driven the land use changes.Possible sustainable land use measures included construction of a land management system, land planning, development of potential land resources, new technology applications, and marine ecological and environmental protection.

  16. 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.

  17. 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.

  18. 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.

  19. Social Capital, Social Control, and Changes in Victimization Rates

    Science.gov (United States)

    Hawdon, James; Ryan, John

    2009-01-01

    A neighborhood-level model of crime that connects the central dimensions of social capital with specific forms of social control is developed. The proposed model is tested using a structural equation model that predicts changes in empirical Bayes log odds of neighborhood victimization rates between 2000 and 2001 in 41 neighborhoods in South…

  20. 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.

  1. 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.

  2. Teaching for Conceptual Change: Examples from Force and Motion.

    Science.gov (United States)

    Hewson, Peter W.; Beeth, Michael E.

    This paper states and discusses general guidelines in teaching for conceptual change. Several important factors that seem to be necessary in meeting the guidelines in normal classrooms are considered. The factors relate to the teacher, student, and the classroom climate. The guidelines are illustrated using examples drawn from a fifth-grade…

  3. Perspectives on Organizational Change in the Canadian Forces

    Science.gov (United States)

    1994-01-01

    men than women exhibited hostility toward homosexuals, and men are more hostile toward gay men than they are toward lesbians . Women are... men who are anti-homosexual seem less capable of developing emotional closeness with other men . Nevertheless, extreme heterosexual antipathy toward ...possibility of attitude change toward homosexuals, tolerance can be taught through education, and if heterosexuals are more accepting of

  4. Analysis of Changing Swarm Rate using Volumetric Strain

    Science.gov (United States)

    Kumazawa, T.; Ogata, Y.; Kimura, K.; Maeda, K.; Kobayashi, A.

    2015-12-01

    Near the eastern coast of Izu peninsula is an active submarine volcanic region in Japan, where magma intrusions have been observed many times. The forecast of earthquake swarm activities and eruptions are serious concern particularly in nearby hot spring resort areas. It is well known that temporal durations of the swarm activities have been correlated with early volumetric strain changes at a certain observation station of about 20 km distance apart. Therefore the Earthquake Research Committee (2010) investigated some empirical statistical relations to predict sizes of the swarm activity. Here we looked at the background seismicity rate changes during these swarm periods using the non-stationary ETAS model (Kumazawa and Ogata, 2013, 2014), and have found the followings. The modified volumetric strain data, by removing the effect of earth tides, precipitation and coseismic jumps, have significantly higher cross-correlations to the estimated background rates of the ETAS model than to the swarm rate-changes. Specifically, the background seismicity rate synchronizes clearer to the strain change by the lags around a half day. These relations suggest an enhanced prediction of earthquakes in this region using volumetric strain measurements. Hence we propose an extended ETAS model where the background rate is modulated by the volumetric strain data. We have also found that the response function to the strain data can be well approximated by an exponential functions with the same decay rate, but that their intersects are inversely proportional to the distances between the volumetric strain-meter and the onset location of the swarm. Our numerical results by the same proposed model show consistent outcomes for the various major swarms in this region.

  5. QALYs: incorporating the rate of change in quality of life.

    Science.gov (United States)

    Katostaras, Theofanis; Katostara, Niki

    2013-01-01

    The need for comparisons and economic evaluations between various health care interventions requires the evaluation of health-related quality of life. To ensure comparability in terms of the duration of any given condition, measures of quality have to integrate the parameter of time, as is the case in measures like QALY. Usually, the rate of change of quality that results from a given intervention is not incorporated in these measures, resulting in a systematically erroneous estimation of QALYs. This estimation error may lead to either a lower QALYs' value compared to the true one, when quality of life improves with a decreasing rate or deteriorates with an increasing rate, or to a higher QALYs' value compared to the true one, when quality of life improves with an increasing rate or deteriorates with a decreasing rate. The proposed method for the estimation of QALYs takes into account the rate of change in health-related quality of life at all stages and discloses deviations up to 16.67% from currently used methods.

  6. [Dynamics of heart rate changes in rats following stepwise change of treadmill running speed].

    Science.gov (United States)

    Tarasova, O S; Borzykh, A A; Kuz'min, I V; Borovik, A S; Lukoshkova, E V; Sharova, A P; Vinogradova, O L; Grigor'ev, A I

    2012-11-01

    Amplitude and temporal responses of heart rate to stepwise increase or decrease of treadmill running intensity were investigated in rats. Heart rate amplitude response was shown to be connected mainly with the change of sympathetic nervous activity whereas heart rate temporal response was shown to be determined predominantly by parasympathetic cardiotrophic influences.

  7. 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%.

  8. 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%).

  9. External Costs as Driving Forces of Land Use Changes

    Directory of Open Access Journals (Sweden)

    Dirk Loehr

    2010-04-01

    Full Text Available Land conversion is often not carried out in a sustainable way. The loss of arable land and biodiversity, concern about food security and rising costs of infrastructure due to urban sprawl are just some of the problems under discussion. This paper compares Germany, China and Cambodia. The article points out that, despite huge differences in institutions and governance, unsustainable land use changes mostly have some patterns in common: The beneficiaries of land conversion are often well-organized actors, whereas the costs of land conversion are often shifted to poorly organized groups and to society as a whole. A sustainable land use policy has to look for a better coupling of benefits and costs of land use changes. In order to achieve this goal, the article suggests completing the planning law with a suitable economic framework.

  10. Effects of climate change on plant population growth rate and community composition change.

    Science.gov (United States)

    Chang, Xiao-Yu; Chen, Bao-Ming; Liu, Gang; Zhou, Ting; Jia, Xiao-Rong; Peng, Shao-Lin

    2015-01-01

    The impacts of climate change on forest community composition are still not well known. Although directional trends in climate change and community composition change were reported in recent years, further quantitative analyses are urgently needed. Previous studies focused on measuring population growth rates in a single time period, neglecting the development of the populations. Here we aimed to compose a method for calculating the community composition change, and to testify the impacts of climate change on community composition change within a relatively short period (several decades) based on long-term monitoring data from two plots-Dinghushan Biosphere Reserve, China (DBR) and Barro Colorado Island, Panama (BCI)-that are located in tropical and subtropical regions. We proposed a relatively more concise index, Slnλ, which refers to an overall population growth rate based on the dominant species in a community. The results indicated that the population growth rate of a majority of populations has decreased over the past few decades. This decrease was mainly caused by population development. The increasing temperature had a positive effect on population growth rates and community change rates. Our results promote understanding and explaining variations in population growth rates and community composition rates, and are helpful to predict population dynamics and population responses to climate change.

  11. Effects of climate change on plant population growth rate and community composition change.

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Chang

    Full Text Available The impacts of climate change on forest community composition are still not well known. Although directional trends in climate change and community composition change were reported in recent years, further quantitative analyses are urgently needed. Previous studies focused on measuring population growth rates in a single time period, neglecting the development of the populations. Here we aimed to compose a method for calculating the community composition change, and to testify the impacts of climate change on community composition change within a relatively short period (several decades based on long-term monitoring data from two plots-Dinghushan Biosphere Reserve, China (DBR and Barro Colorado Island, Panama (BCI-that are located in tropical and subtropical regions. We proposed a relatively more concise index, Slnλ, which refers to an overall population growth rate based on the dominant species in a community. The results indicated that the population growth rate of a majority of populations has decreased over the past few decades. This decrease was mainly caused by population development. The increasing temperature had a positive effect on population growth rates and community change rates. Our results promote understanding and explaining variations in population growth rates and community composition rates, and are helpful to predict population dynamics and population responses to climate change.

  12. Forced Ion Migration for Chalcogenide Phase Change Memory Device

    Science.gov (United States)

    Campbell, Kristy A (Inventor)

    2013-01-01

    Non-volatile memory devices with two stacked layers of chalcogenide materials comprising the active memory device have been investigated for their potential as phase-change memories. The devices tested included GeTe/SnTe, Ge2Se3/SnTe, and Ge2Se3/SnSe stacks. All devices exhibited resistance switching behavior. The polarity of the applied voltage with respect to the SnTe or SnSe layer was critical to the memory switching properties, due to the electric field induced movement of either Sn or Te into the Ge-chalcogenide layer. One embodiment of the invention is a device comprising a stack of chalcogenide-containing layers which exhibit phase-change switching only after a reverse polarity voltage potential is applied across the stack causing ion movement into an adjacent layer and thus "activating" the device to act as a phase-change random access memory device or a reconfigurable electronics device when the applied voltage potential is returned to the normal polarity. Another embodiment of the invention is a device that is capable of exhibiting more than two data states.

  13. Forced changes to twentieth century ENSO diversity in a last Millennium context

    Science.gov (United States)

    Stevenson, Samantha; Capotondi, Antonietta; Fasullo, John; Otto-Bliesner, Bette

    2017-03-01

    The El Niño/Southern Oscillation (ENSO) exhibits considerable differences between the evolution of individual El Niño and La Niña events (`ENSO diversity'), with significant implications for impacts studies. However, the degree to which external forcing may affect ENSO diversity is not well understood, due to both internal variability and potentially compensatory contributions from multiple forcings. The Community Earth System Model Last Millennium Ensemble (CESM LME) provides an ideal testbed for studying the sensitivity of twentieth century ENSO to forced climate changes, as it contains many realizations of the 850-2005 period with differing combinations of forcings. Metrics of ENSO amplitude and diversity are compared across LME simulations, and although forced changes to ENSO amplitude are generally small, forced changes to diversity are often detectable. Anthropogenic changes to greenhouse gas and ozone/aerosol emissions modify the persistence of Eastern and Central Pacific El Niño events, through shifts in the upwelling and zonal advective feedbacks; these influences generally cancel one another over the twentieth century. Other forcings can also be quite important: land use changes amplify Eastern Pacific El Niño events via modulating zonal advective heating, and orbital forcing tends to preferentially terminate twentieth century Central Pacific El Niño events due to enhanced eastern Pacific cooling during boreal winter and spring. Our results indicate that multiple anthropogenic and natural forcings can have substantial impacts on ENSO diversity, and suggest that correctly representing the net ENSO diversity response to climate change will depend on the precise balance between all these influences.

  14. 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.

  15. Forced and Unforced Changes of Indian Ocean Temperature and Land-Sea Temperature Gradient

    Science.gov (United States)

    Achutarao, K. M.; Thanigachalam, A.

    2015-12-01

    Sea surface temperature (SST) over the Indian Ocean is directly connected with circulation, winds, precipitation, humidity, etc. over India. Increased SSTs are a major consequence of climate change driven largely by anthropogenic factors. Recent literature points to weakening of the Indian Summer Monsoon possibly because of decreased land-sea temperature gradient due to faster rate of warming of the oceans compared to land regions. We examine changes in the SST over the Indian Ocean using two observational datasets; HadISST (v1.1) and ERSST (v3b). Based on trend differences between two time periods (1979-2009 and 1948-1978) we identify four regions in the Indian Ocean with different signatures of change - Bay of Bengal (BOB), Arabian Sea (AS), Southwest Indian Ocean (SWIO), and Southeast Indian Ocean (SEIO). We first quantify the extent to which the SST trends over multiple time-scales (20, 30, 50 and 100-years) are outside of the range expected from internal variability of the climate system. We make use of output data from long control run simulations from the Coupled Model Intercomparison Project Phase-5 (CMIP5) database in order to estimate the contribution of external forcings to the observed trends. Using optimal fingerprint Detection and Attribution methods we quantify the contributions of various natural and anthropogenic forcings by making use of the suite of experiments (piControl, historical, historicalNat, historicalAnt, historicalGHG, and historicalAA) from CMIP5 are used in this study. We will also address the question of what drives the observed weakening of land-ocean temperature gradients.

  16. Climate change is projected to outpace rates of niche change in grasses.

    Science.gov (United States)

    Cang, F Alice; Wilson, Ashley A; Wiens, John J

    2016-09-01

    Climate change may soon threaten much of global biodiversity, especially if species cannot adapt to changing climatic conditions quickly enough. A critical question is how quickly climatic niches change, and if this speed is sufficient to prevent extinction as climates warm. Here, we address this question in the grass family (Poaceae). Grasses are fundamental to one of Earth's most widespread biomes (grasslands), and provide roughly half of all calories consumed by humans (including wheat, rice, corn and sorghum). We estimate rates of climatic niche change in 236 species and compare these with rates of projected climate change by 2070. Our results show that projected climate change is consistently faster than rates of niche change in grasses, typically by more than 5000-fold for temperature-related variables. Although these results do not show directly what will happen under global warming, they have troubling implications for a major biome and for human food resources.

  17. Research on driving forces for rural settlement land changes in China

    Institute of Scientific and Technical Information of China (English)

    CHEN Chun; FENG Chang-chun

    2010-01-01

    During the rapid urbanization period, the contradiction between demand for the construction land and the preservation of cultivated land for food security is getting more and more serious in China. With the urbanization the rural settlement land is increasing instead of decreasing. This paper aims at finding the driving forces for rural settlement land expansion. Based on land use change survey data (1996-2006) by the Ministry. of Land and Resources P. R. C., this paper finds that per capita area for rural settlement land is more than per capita area for city township and industrial land in each province except Tibet. Besides, rural settlement land area and per capita rural settlement land area are increasing while the rural population is decreasing in most provinces. The main problems of rural settlement land use are low efficiency, high vacancy rate, chaotic layout and illegal occupancy. Then the driving forces for rural settlement land expansion, including economic development family income, family scale, psychological factors, urbanization, transportation, lack of planning, limited circulation of dwelling-house land and imperfect social security, are explored based on above analysts. Finally, policy recommendations, in view of different influencing factors, are put forward to control the disorder expansion of rural settlement land.

  18. Accuracy of discrimination, rate of responding, and resistance to change.

    Science.gov (United States)

    Nevin, John A; Milo, Jessica; Odum, Amy L; Shahan, Timothy A

    2003-05-01

    Pigeons were trained on multiple schedules in which responding on a center key produced matching-to-sample trials according to the same variable-interval 30-s schedules in both components. Matching trials consisted of a vertical or tilted line sample on the center key followed by vertical and tilted comparisons on the side keys. Correct responses to comparison stimuli were reinforced with probability .80 in the rich component and .20 in the lean component. Baseline response rates and matching accuracies generally were higher in the rich component, consistent with previous research. When performance was disrupted by prefeeding, response-independent food during intercomponent intervals, intrusion of a delay between sample and comparison stimuli, or extinction, both response rates and matching accuracies generally decreased. Proportions of baseline response rate were greater in the rich component for all disrupters except delay, which had relatively small and inconsistent effects on response rate. By contrast, delay had large and consistent effects on matching accuracy, and proportions of baseline matching accuracy were greater in the rich component for all four disrupters. The dissociation of response rate and accuracy with delay reflects the localized impact of delay on matching performance. The similarity of the data for response rate and accuracy with prefeeding, response-independent food, and extinction shows that matching performance, like response rate, is more resistant to change in a rich than in a lean component. This result extends resistance to change analyses from the frequency of response emission to the degree of stimulus control, and suggests that the strength of discriminating, like the strength of responding, is positively related to rate of reinforcement.

  19. The rate of molecular adaptation in a changing environment.

    Science.gov (United States)

    Lourenço, João M; Glémin, Sylvain; Galtier, Nicolas

    2013-06-01

    It is currently unclear whether the amino acid substitutions that occur during protein evolution are primarily driven by adaptation, or reflect the random accumulation of neutral changes. When estimated from genomic data, the proportion of adaptive amino acid substitutions, called α, was found to vary greatly across species, from nearly zero in humans to above 0.5 in Drosophila. These variations have been interpreted as reflecting differences in effective population size, adaptation being supposedly more efficient in large populations. Here, we investigate the influence of effective population size and other biological parameters on the rate of adaptive evolution by simulating the evolution of a coding sequence under Fisher's geometric formalism. We explicitly model recurrent environmental changes and the subsequent adaptive walks, followed by periods of stasis during which purifying selection dominates. We show that, under a variety of conditions, the effective population size has only a moderate influence on α, and an even weaker influence on the per generation rate of selective sweeps, modifying the prevalent view in current literature. The rate of environmental change and, interestingly, the dimensionality of the phenotypic space (organismal complexity) affect the adaptive rate more deeply than does the effective population size. We discuss the reasons why verbal arguments have been misleading on that subject and revisit the empirical evidence. Our results question the relevance of the "α" parameter as an indicator of the efficiency of molecular adaptation.

  20. Changes in Scottish suicide rates during the Second World War

    Directory of Open Access Journals (Sweden)

    Humphry Roger W

    2006-06-01

    Full Text Available Abstract Background It is believed that total reported suicide rates tend to decrease during wartime. However, analysis of suicide rates during recent conflicts suggests a more complex picture, with increases in some age groups and changes in method choice. As few age and gender specific analyses of more distant conflicts have been conducted, it is not clear if these findings reflect a change in the epidemiology of suicide in wartime. Therefore, we examined suicide rates in Scotland before, during and after the Second World War to see if similar features were present. Methods Data on deaths in Scotland recorded as suicide during the period 1931 – 1952, and population estimates for each of these years, were obtained from the General Register Office for Scotland. Using computer spreadsheets, suicide rates by gender, age and method were calculated. Forward stepwise logistic regression was used to assess the effect of gender, war and year on suicide rates using SAS V8.2. Results The all-age suicide rate among both men and women declined during the period studied. However, when this long-term decline is taken into account, the likelihood of suicide during the Second World War was higher than during both the pre-War and post-War periods. Suicide rates among men aged 15–24 years rose during the Second World War, peaking at 148 per million (41 deaths during 1942 before declining to 39 per million (10 deaths by 1945, while the rate among men aged 25–34 years reached 199 per million (43 deaths during 1943 before falling to 66 per million (23 deaths by 1946. This was accompanied by an increase in male suicides attributable to firearms and explosives during the War years which decreased following its conclusion. Conclusion All age male and female suicide rates decreased in Scotland during World War II. However, once the general background decrease in suicide rates over the whole period is accounted for, the likelihood of suicide among the entire

  1. The average rate of change for continuous time models.

    Science.gov (United States)

    Kelley, Ken

    2009-05-01

    The average rate of change (ARC) is a concept that has been misunderstood in the applied longitudinal data analysis literature, where the slope from the straight-line change model is often thought of as though it were the ARC. The present article clarifies the concept of ARC and shows unequivocally the mathematical definition and meaning of ARC when measurement is continuous across time. It is shown that the slope from the straight-line change model generally is not equal to the ARC. General equations are presented for two measures of discrepancy when the slope from the straight-line change model is used to estimate the ARC in the case of continuous time for any model linear in its parameters, and for three useful models nonlinear in their parameters.

  2. Net radiative forcing due to changes in regional emissions of tropospheric ozone precursors

    Science.gov (United States)

    Naik, Vaishali; Mauzerall, Denise; Horowitz, Larry; Schwarzkopf, M. Daniel; Ramaswamy, V.; Oppenheimer, Michael

    2005-12-01

    The global distribution of tropospheric ozone (O3) depends on the emission of precursors, chemistry, and transport. For small perturbations to emissions, the global radiative forcing resulting from changes in O3 can be expressed as a sum of forcings from emission changes in different regions. Tropospheric O3 is considered in present climate policies only through the inclusion of indirect effect of CH4 on radiative forcing through its impact on O3 concentrations. The short-lived O3 precursors (NOx, CO, and NMHCs) are not directly included in the Kyoto Protocol or any similar climate mitigation agreement. In this study, we quantify the global radiative forcing resulting from a marginal reduction (10%) in anthropogenic emissions of NOx alone from nine geographic regions and a combined marginal reduction in NOx, CO, and NMHCs emissions from three regions. We simulate, using the global chemistry transport model MOZART-2, the change in the distribution of global O3 resulting from these emission reductions. In addition to the short-term reduction in O3, these emission reductions also increase CH4 concentrations (by decreasing OH); this increase in CH4 in turn counteracts part of the initial reduction in O3 concentrations. We calculate the global radiative forcing resulting from the regional emission reductions, accounting for changes in both O3 and CH4. Our results show that changes in O3 production and resulting distribution depend strongly on the geographical location of the reduction in precursor emissions. We find that the global O3 distribution and radiative forcing are most sensitive to changes in precursor emissions from tropical regions and least sensitive to changes from midlatitude and high-latitude regions. Changes in CH4 and O3 concentrations resulting from NOx emission reductions alone produce offsetting changes in radiative forcing, leaving a small positive residual forcing (warming) for all regions. In contrast, for combined reductions of anthropogenic

  3. Resistance to change of forgetting functions and response rates.

    Science.gov (United States)

    Odum, Amy L; Shahan, Timothy A; Nevin, John A

    2005-07-01

    This experiment examined the effects of reinforcement probability on resistance to change of remembering and response rate. Pigeons responded on a two-component multiple schedule in which completion of a variable-interval 20-s schedule produced delayed matching-to-sample trials in both components. Each session included four delays (0.1 s, 2 s, 4 s, and 8 s) between sample termination and presentation of comparison stimuli in both components. The two components differed in the probability of reinforcement arranged for correct matches (i.e., rich, p = .9; lean, p = .1). Response rates during the variable-interval portion of the procedure were higher in the rich component during baseline and more resistant to the disruptive effects of intercomponent food and extinction. Forgetting functions were constructed by examining matching accuracy as a function of delay duration. Baseline accuracy was higher in the rich component than in the lean component as measured by differences in the gamma-intercept of the forgetting functions (i.e., initial discrimination), rather than from differences in the slope of the forgetting function (i.e., rate of forgetting). Intercomponent food increased the rate of forgetting relatively more in the lean component than in the rich component, but initial discrimination was not systematically affected. Extinction reduced initial discrimination relatively more in the lean component than in the rich component, but did not systematically affect rate of forgetting. These results are consistent with our previous data suggesting that, as for response rate, accuracy and resistance to change of discriminating are positively related to rate of reinforcement. These data also suggest that the disruptability of remembering depends on the conditions of reinforcement, but the way in which remembering is disrupted depends on the nature of the disruptor.

  4. Networking Technologies and the Rate of Technological Change

    Directory of Open Access Journals (Sweden)

    Charles Mitchell

    2005-12-01

    Full Text Available Network technology is changing rapidly and those adept at ICT analysis need resolve rate of change issues. Developments in networking now are in the direction of heuristic intelligence. Since about 1980, networking techniques have encouraged combining bits of information with imagination cognitively to improve ideas about reality. ICT enterprise projects utilize networking to sustain requisite imagination. Assumptions and misassuptions of project builders are rationally comprehended as networking sustains creative processes. The monopolization of valuable network techniques influences in the direction of esoteric networking. Data presents that substantial knowledge and networking is now occurring globally. As a netaphor, networking

  5. Networking Technologies and the Rate of Technological Change

    Directory of Open Access Journals (Sweden)

    Charles Mitchell

    2005-12-01

    Full Text Available Network technology is changing rapidly and those adept at ICT analysis need resolve rate of change issues. Developments in networking now are in the direction of heuristic intelligence. Since about 1980, networking techniques have encouraged combining bits of information with imagination cognitively to improve ideas about reality. ICT enterprise projects utilize networking to sustain requisite imagination. Assumptions and misassuptions of project builders are rationally comprehended as networking sustains creative processes. The monopolization of valuable network techniques influences in the direction of esoteric networking. Data presents that substantial knowledge and networking is now occurring globally. As a netaphor, networking

  6. FPGA realization of Farrow structure for sampling rate change

    Directory of Open Access Journals (Sweden)

    Marković Bogdan

    2016-01-01

    Full Text Available In numerous implementations of modern telecommunications and digital audio systems there is a need for sampling rate change of the system input signal. When the relation between signal input and output sampling frequencies is a fraction of two large integer numbers, Lagrange interpolation based on Farrow structure can be used for the efficient realization of the resample block. This paper highlights efficient realization and estimation of necessary resources for polynomial cubic Lagrange interpolation in the case of the demand for the signal sampling rate change with the factor 160/147 on Field-Programmable Gate Array architecture (FPGA. [Projekat Ministarstva nauke Republike Srbije, br. TR-32023 i br. TR-32028

  7. 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.

  8. Probability of detection of clinical seizures using heart rate changes.

    Science.gov (United States)

    Osorio, Ivan; Manly, B F J

    2015-08-01

    Heart rate-based seizure detection is a viable complement or alternative to ECoG/EEG. This study investigates the role of various biological factors on the probability of clinical seizure detection using heart rate. Regression models were applied to 266 clinical seizures recorded from 72 subjects to investigate if factors such as age, gender, years with epilepsy, etiology, seizure site origin, seizure class, and data collection centers, among others, shape the probability of EKG-based seizure detection. Clinical seizure detection probability based on heart rate changes, is significantly (pprobability of detecting clinical seizures (>0.8 in the majority of subjects) using heart rate is highest for complex partial seizures, increases with a patient's years with epilepsy, is lower for females than for males and is unrelated to the side of hemisphere origin. Clinical seizure detection probability using heart rate is multi-factorially dependent and sufficiently high (>0.8) in most cases to be clinically useful. Knowledge of the role that these factors play in shaping said probability will enhance its applicability and usefulness. Heart rate is a reliable and practical signal for extra-cerebral detection of clinical seizures originating from or spreading to central autonomic network structures. Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  9. 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.

  10. 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.

  11. Stock price change rate prediction by utilizing social network activities.

    Science.gov (United States)

    Deng, Shangkun; Mitsubuchi, Takashi; Sakurai, Akito

    2014-01-01

    Predicting stock price change rates for providing valuable information to investors is a challenging task. Individual participants may express their opinions in social network service (SNS) before or after their transactions in the market; we hypothesize that stock price change rate is better predicted by a function of social network service activities and technical indicators than by a function of just stock market activities. The hypothesis is tested by accuracy of predictions as well as performance of simulated trading because success or failure of prediction is better measured by profits or losses the investors gain or suffer. In this paper, we propose a hybrid model that combines multiple kernel learning (MKL) and genetic algorithm (GA). MKL is adopted to optimize the stock price change rate prediction models that are expressed in a multiple kernel linear function of different types of features extracted from different sources. GA is used to optimize the trading rules used in the simulated trading by fusing the return predictions and values of three well-known overbought and oversold technical indicators. Accumulated return and Sharpe ratio were used to test the goodness of performance of the simulated trading. Experimental results show that our proposed model performed better than other models including ones using state of the art techniques.

  12. Stock Price Change Rate Prediction by Utilizing Social Network Activities

    Science.gov (United States)

    Mitsubuchi, Takashi; Sakurai, Akito

    2014-01-01

    Predicting stock price change rates for providing valuable information to investors is a challenging task. Individual participants may express their opinions in social network service (SNS) before or after their transactions in the market; we hypothesize that stock price change rate is better predicted by a function of social network service activities and technical indicators than by a function of just stock market activities. The hypothesis is tested by accuracy of predictions as well as performance of simulated trading because success or failure of prediction is better measured by profits or losses the investors gain or suffer. In this paper, we propose a hybrid model that combines multiple kernel learning (MKL) and genetic algorithm (GA). MKL is adopted to optimize the stock price change rate prediction models that are expressed in a multiple kernel linear function of different types of features extracted from different sources. GA is used to optimize the trading rules used in the simulated trading by fusing the return predictions and values of three well-known overbought and oversold technical indicators. Accumulated return and Sharpe ratio were used to test the goodness of performance of the simulated trading. Experimental results show that our proposed model performed better than other models including ones using state of the art techniques. PMID:24790586

  13. Stock Price Change Rate Prediction by Utilizing Social Network Activities

    Directory of Open Access Journals (Sweden)

    Shangkun Deng

    2014-01-01

    Full Text Available Predicting stock price change rates for providing valuable information to investors is a challenging task. Individual participants may express their opinions in social network service (SNS before or after their transactions in the market; we hypothesize that stock price change rate is better predicted by a function of social network service activities and technical indicators than by a function of just stock market activities. The hypothesis is tested by accuracy of predictions as well as performance of simulated trading because success or failure of prediction is better measured by profits or losses the investors gain or suffer. In this paper, we propose a hybrid model that combines multiple kernel learning (MKL and genetic algorithm (GA. MKL is adopted to optimize the stock price change rate prediction models that are expressed in a multiple kernel linear function of different types of features extracted from different sources. GA is used to optimize the trading rules used in the simulated trading by fusing the return predictions and values of three well-known overbought and oversold technical indicators. Accumulated return and Sharpe ratio were used to test the goodness of performance of the simulated trading. Experimental results show that our proposed model performed better than other models including ones using state of the art techniques.

  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. The school as a force for community change in Tanzania

    Science.gov (United States)

    Maliyamkono, T. L.

    1980-09-01

    In newly independent countries where traditional theories of educational policy have continued to be followed, education has persisted as little more than a sophisticated mechanism for the recruitment of elites, and there has been an increased dependence on the advanced industrial nations for aid, experts and educational models. Tanzania, however, has attempted to break away from traditional strategies, and the author here describes and analyses the impact of two of the most far-reaching reforms — Education for Self-Reliance, and Decentralization — on national goals and policies. President Nyerere enunciated the objectives for Education for Self-Reliance in 1967 as relating education to rural life, correcting the elitist bias of education, and changing negative attitudes among students towards agriculture and rural life. Five major programmes of reform covering primary and secondary education, teacher and higher education, and examinations were to be pursued, ensuring a closer integration of schools with local communities, e.g., through school farms and co-operative shops, and making curricula directly relevant to local needs. A policy of Decentralization is being implemented, allowing, theoretically at least, a much greater participation at community level in decision-making. In primary and adult education this has already been effected to some extent, though there is evidence to suggest that decentralization in some regions and districts has resulted in the creation of local bureaucratic machinery for control, defeating the intention of the reform. Decentralization of secondary and teacher education is likely to follow, leaving only higher education centrally controlled for manpower training and allocation purposes. Finally the author discusses the question of the transferability of the Tanzanian reforms.

  16. Assessing historical rate changes in global tsunami occurrence

    Science.gov (United States)

    Geist, E.L.; Parsons, T.

    2011-01-01

    The global catalogue of tsunami events is examined to determine if transient variations in tsunami rates are consistent with a Poisson process commonly assumed for tsunami hazard assessments. The primary data analyzed are tsunamis with maximum sizes >1m. The record of these tsunamis appears to be complete since approximately 1890. A secondary data set of tsunamis >0.1m is also analyzed that appears to be complete since approximately 1960. Various kernel density estimates used to determine the rate distribution with time indicate a prominent rate change in global tsunamis during the mid-1990s. Less prominent rate changes occur in the early- and mid-20th century. To determine whether these rate fluctuations are anomalous, the distribution of annual event numbers for the tsunami catalogue is compared to Poisson and negative binomial distributions, the latter of which includes the effects of temporal clustering. Compared to a Poisson distribution, the negative binomial distribution model provides a consistent fit to tsunami event numbers for the >1m data set, but the Poisson null hypothesis cannot be falsified for the shorter duration >0.1m data set. Temporal clustering of tsunami sources is also indicated by the distribution of interevent times for both data sets. Tsunami event clusters consist only of two to four events, in contrast to protracted sequences of earthquakes that make up foreshock-main shock-aftershock sequences. From past studies of seismicity, it is likely that there is a physical triggering mechanism responsible for events within the tsunami source 'mini-clusters'. In conclusion, prominent transient rate increases in the occurrence of global tsunamis appear to be caused by temporal grouping of geographically distinct mini-clusters, in addition to the random preferential location of global M >7 earthquakes along offshore fault zones.

  17. Land Use Change and Driving Forces in Guangzhou City during 1996- 2012

    Institute of Scientific and Technical Information of China (English)

    Yiying; YAO; Dafang; WU; Yanyan; LIU; Yihua; LIU; Qixian; CHEN; Haolong; CHEN; Jiaxin; WU; Jialiang; ZHONG

    2015-01-01

    Based on the statistical data of land use change,from the perspective of sustainable use,we use literature inquiry,statistical analysis,GIS spatial analysis and dynamic degree model of land use,to analyze the land use change characteristics,land use amount and spatial distribution characteristics in Guangzhou City during 1996- 2012,and further elaborate the driving forces of land use change to get the basic law of land use change in Guangzhou City. The results show that the construction land was rapidly expanded,causing a significant reduction in arable land( from 129286 ha in 1996 to 84567 ha in 2012); in construction land,the land for residential,industrial and mining use and transportation land dramatically increased,and the single dynamic degree of transportation land was close to 7. 1%. In comparison with other developed cities,it is found that economic factors and policy factors are important factors affecting land use change in Guangzhou City,and the growth rate of economic density of land was high in Tianhe District and Yuexiu District. From the perspective of sustainable use,the future land use in Guangzhou City needs to better coordinate the relationship between various types of land,between socio-economic development and coordinated land use development,between environmental protection and land development and utilization. Through a series of land consolidation activities,it is necessary to strengthen the protection of farmland,improve the intensive and economical use of construction land,improve the ecological environment,and coordinate development of urban and rural areas,to ultimately achieve sustainable land use in Guangzhou City.

  18. 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+).

  19. ASAS Eclipsing Binaries with Observed High Period Change Rates

    CERN Document Server

    Pilecki, B; Poleski, R

    2007-01-01

    We present 31 bright eclipsing contact and semi-detached binaries that showed high period change rates in a 5 year interval in observations by the All-Sky Automated Survey (ASAS). The time-scales of these changes range from only 50 up to 400 kyr. The orbital periods of 10 binaries are increasing and of 21 are decreasing, and even a larger excess is seen in contact binaries, where the numbers are 5 and 17, respectively. Period change has previously been noticed for only two of these binaries; our observations confirmed a secular period drift for SV Cen and period oscillations for VY Cet. The spectroscopic quadruple system V1084 Sco shows both period change and brightness modulation. All investigated binaries were selected from a sample of 1711 (1135 contact and 576 semi-detached) that fulfilled all criteria of data quality. We also introduce a "branch" test to check if luminosity changes on part of the binary's photosphere has led to a spurious or poorly characterized period change detection.

  20. The ocean's role in polar climate change: asymmetric Arctic and Antarctic responses to greenhouse gas and ozone forcing.

    Science.gov (United States)

    Marshall, John; Armour, Kyle C; Scott, Jeffery R; Kostov, Yavor; Hausmann, Ute; Ferreira, David; Shepherd, Theodore G; Bitz, Cecilia M

    2014-07-13

    In recent decades, the Arctic has been warming and sea ice disappearing. By contrast, the Southern Ocean around Antarctica has been (mainly) cooling and sea-ice extent growing. We argue here that interhemispheric asymmetries in the mean ocean circulation, with sinking in the northern North Atlantic and upwelling around Antarctica, strongly influence the sea-surface temperature (SST) response to anthropogenic greenhouse gas (GHG) forcing, accelerating warming in the Arctic while delaying it in the Antarctic. Furthermore, while the amplitude of GHG forcing has been similar at the poles, significant ozone depletion only occurs over Antarctica. We suggest that the initial response of SST around Antarctica to ozone depletion is one of cooling and only later adds to the GHG-induced warming trend as upwelling of sub-surface warm water associated with stronger surface westerlies impacts surface properties. We organize our discussion around 'climate response functions' (CRFs), i.e. the response of the climate to 'step' changes in anthropogenic forcing in which GHG and/or ozone-hole forcing is abruptly turned on and the transient response of the climate revealed and studied. Convolutions of known or postulated GHG and ozone-hole forcing functions with their respective CRFs then yield the transient forced SST response (implied by linear response theory), providing a context for discussion of the differing warming/cooling trends in the Arctic and Antarctic. We speculate that the period through which we are now passing may be one in which the delayed warming of SST associated with GHG forcing around Antarctica is largely cancelled by the cooling effects associated with the ozone hole. By mid-century, however, ozone-hole effects may instead be adding to GHG warming around Antarctica but with diminished amplitude as the ozone hole heals. The Arctic, meanwhile, responding to GHG forcing but in a manner amplified by ocean heat transport, may continue to warm at an accelerating rate.

  1. Perspectives on massive coral growth rates in a changing ocean.

    Science.gov (United States)

    Lough, Janice M; Cantin, Neal E

    2014-06-01

    The tropical ocean environment is changing at an unprecedented rate, with warming and severe tropical cyclones creating obvious impacts to coral reefs within the last few decades and projections of acidification raising concerns for the future of these iconic and economically important ecosystems. Documenting variability and detecting change in global and regional climate relies upon high-quality observational records of climate variables supplemented, prior to the mid-19th century, with reconstructions from various sources of proxy climate information. Here we review how annual density banding patterns that are recorded in the skeletons of massive reef-building corals have been used to document environmental change and impacts within coral reefs. Massive corals provide a historical perspective of continuous calcification processes that pre-date most ecological observations of coral reefs. High-density stress bands, abrupt declines in annual linear extension, and evidence of partial mortality within the skeletal growth record reveal signatures of catastrophic stress events that have recently been attributed to mass bleaching events caused by unprecedented thermal stress. Comparison of recent trends in annual calcification with century-scale baseline calcification rates reveals that the frequency of growth anomalies has increased since the late 1990s throughout most of the world's coral reef ecosystems. Continuous coral growth histories provide valuable retrospective information on the coral response to environmental change and the consequences of anthropogenic climate change. Co-ordinated efforts to synthesize and combine global calcification histories will greatly enhance our understanding of current calcification responses to a changing ocean. © 2014 Marine Biological Laboratory.

  2. 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.

  3. 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.

  4. New Congressional Climate Change Task Force Calls on President to Use Administrative Authority

    Science.gov (United States)

    Showstack, Randy

    2013-02-01

    Spurred by U.S. congressional inaction on climate change and by President Barack Obama's comments on the topic in his 21 January inaugural address, several Democratic members of Congress announced at a Capitol Hill briefing the formation of a bicameral task force on climate change. In addition, they have called on the president to use his administrative authority to deal with the issue.

  5. Effect of Technology Enhanced Conceptual Change Texts on Students' Understanding of Buoyant Force

    Science.gov (United States)

    Ozkan, Gulbin; Selcuk, Gamze Sezgin

    2015-01-01

    In this study, the effect of technology enhanced conceptual change texts on elementary school students' understanding of buoyant force was investigated. The conceptual change texts (written forms) used in this study are proven for effectiveness and are enriched by using technology support in this study. These texts were tried out on two groups. A…

  6. 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.

  7. The Frank-Starling mechanism is not mediated by changes in rate of cross-bridge detachment.

    Science.gov (United States)

    Wannenburg, T; Janssen, P M; Fan, D; de Tombe, P P

    1997-11-01

    We tested the hypothesis that the Frank-Starling relationship is mediated by changes in the rate of cross-bridge detachment in cardiac muscle. We simultaneously measured isometric force development and the rate of ATP consumption at various levels of Ca2+ activation in skinned rat cardiac trabecular muscles at three sarcomere lengths (2.0, 2.1, and 2.2 microns). The maximum rate of ATP consumption was 1.5 nmol.s-1.microliter fiber vol-1, which represents an estimated adenosinetriphosphatase (ATPase) rate of approximately 10 s-1 per myosin head at 24 degrees C. The rate of ATP consumption was tightly and linearly coupled to the level of isometric force development, and changes in sarcomere length had no effect on the slope of the force-ATPase relationships. The average slope of the force-ATPase relationships was 15.5 pmol.mN-1.mm-1. These results suggest that the mechanisms that underlie the Frank-Starling relationship in cardiac muscle do not involve changes in the kinetics of the apparent detachment step in the cross-bridge cycle.

  8. The effects of climate change and land-use change on demographic rates and population viability.

    Science.gov (United States)

    Selwood, Katherine E; McGeoch, Melodie A; Mac Nally, Ralph

    2015-08-01

    Understanding the processes that lead to species extinctions is vital for lessening pressures on biodiversity. While species diversity, presence and abundance are most commonly used to measure the effects of human pressures, demographic responses give a more proximal indication of how pressures affect population viability and contribute to extinction risk. We reviewed how demographic rates are affected by the major anthropogenic pressures, changed landscape condition caused by human land use, and climate change. We synthesized the results of 147 empirical studies to compare the relative effect size of climate and landscape condition on birth, death, immigration and emigration rates in plant and animal populations. While changed landscape condition is recognized as the major driver of species declines and losses worldwide, we found that, on average, climate variables had equally strong effects on demographic rates in plant and animal populations. This is significant given that the pressures of climate change will continue to intensify in coming decades. The effects of climate change on some populations may be underestimated because changes in climate conditions during critical windows of species life cycles may have disproportionate effects on demographic rates. The combined pressures of land-use change and climate change may result in species declines and extinctions occurring faster than otherwise predicted, particularly if their effects are multiplicative.

  9. Instrumented Footwear Inserts: A New Tool for Measuring Forces and Biomechanical State Changes During Dynamic Movements

    Science.gov (United States)

    2017-03-03

    1 Instrumented Footwear Inserts: A New Tool For Measuring Forces and Biomechanical State Changes During Dynamic Movements Joe Lacirignola1...bones and joints are repeatedly subjected to aggressive movements and high forces. The ability to measure these elements during training would be a...critical enabler for prevention of injury and development of more quantitative training procedures that focus on ambulatory mobility and agility. It

  10. Effect of temperature on crossbridge force changes during fatigue and recovery in intact mouse muscle fibers.

    Directory of Open Access Journals (Sweden)

    Marta Nocella

    Full Text Available Repetitive or prolonged muscle contractions induce muscular fatigue, defined as the inability of the muscle to maintain the initial tension or power output. In the present experiments, made on intact fiber bundles from FDB mouse, fatigue and recovery from fatigue were investigated at 24°C and 35°C. Force and stiffness were measured during tetani elicited every 90 s during the pre-fatigue control phase and recovery and every 1.5 s during the fatiguing phase made of 105 consecutive tetani. The results showed that force decline could be split in an initial phase followed by a later one. Loss of force during the first phase was smaller and slower at 35°C than at 24°C, whereas force decline during the later phase was greater at 35°C so that total force depression at the end of fatigue was the same at both temperatures. The initial force decline occurred without great reduction of fiber stiffness and was attributed to a decrease of the average force per attached crossbridge. Force decline during the later phase was accompanied by a proportional stiffness decrease and was attributed to a decrease of the number of attached crossbridge. Similarly to fatigue, at both 24 and 35°C, force recovery occurred in two phases: the first associated with the recovery of the average force per attached crossbridge and the second due to the recovery of the pre-fatigue attached crossbridge number. These changes, symmetrical to those occurring during fatigue, are consistent with the idea that, i initial phase is due to the direct fast inhibitory effect of [Pi]i increase during fatigue on crossbridge force; ii the second phase is due to the delayed reduction of Ca(2+ release and /or reduction of the Ca(2+ sensitivity of the myofibrils due to high [Pi]i.

  11. Role of radiatively forced temperature changes in enhanced semi-arid warming over East Asia

    Directory of Open Access Journals (Sweden)

    X. Guan

    2015-08-01

    Full Text Available As the climate change occurred over East Asia since 1950s, intense interest and debate have arisen concerning the contribution of human activities to the warming observed in previous decades. In this study, we investigate surface temperature change using a recently developed methodology that can successfully identify and separate the dynamically induced temperature (DIT and radiatively forced temperature (RFT changes in raw surface air temperature (SAT data. For regional averages, DIT and RFT make 43.7 and 56.3 % contributions to the SAT over East Asia, respectively. The DIT changes dominate the SAT decadal variability and are mainly determined by internal climate variability, such as the North Atlantic Oscillation (NAO, Pacific Decadal Oscillation (PDO, and Atlantic Multi-decadal Oscillation (AMO. The radiatively forced SAT changes made major contribution to the global-scale warming trend and the regional-scale enhanced semi-arid warming (ESAW. Such enhanced warming is also found in radiatively forced daily maximum and minimum SAT. The long-term global-mean SAT warming trend is mainly related to radiative forcing produced by global well-mixed greenhouse gases. The regional anthropogenic radiative forcing, however, caused the enhanced warming in the semi-arid region, which may be closely associated with local human activities. Finally, the relationship between global warming hiatus and regional enhanced warming is discussed.

  12. 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.

  13. Dynamic brain mapping of behavior change: tracking response initiation and inhibition to changes in reinforcement rate.

    Science.gov (United States)

    Schlund, Michael W; Magee, Sandy; Hudgins, Caleb D

    2012-10-01

    Adaptive behavior change is supported by executive control processes distributed throughout a prefrontal-striatal-parietal network. Yet, the temporal dynamics of regions in the network have not been characterized. Using functional magnetic resonance imaging (fMRI), we tracked changes brain activation while subjects initiated and inhibited responding in accordance with changes in reinforcement rate. During imaging, subjects completed a free-operant task that involved repeated transitions between fixed-ratio reinforcement and extinction (RF:EXT), where reinforcement rate decreased and responding was inhibited, and between extinction and fixed-ratio reinforcement (EXT:RF), where reinforcement rate increased and responding was initiated. Our whole-brain temporal assessment revealed that transitions which required initiating and inhibiting responding prompted positive phasic responses in a prefrontal-parietal network, the insula and thalamus. However, response initiation prompted by an increase in reinforcement rate during the EXT:RF transition elicited positive phasic responses in reward-sensitive striatal regions. Furthermore, response inhibition prompted by a decrease in reinforcement rate during the RF:EXT transition elicited negative phasic responses in ventral frontal regions sensitive to value and contingency. Our findings highlight the temporal dynamics of a brain network that supports behavioral changes (initiation and inhibition) resulting from changes in local reinforcement rates.

  14. Accounting for radiative forcing from albedo change in future global land-use scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Andrew D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Calvin, Katherine V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Collins, William D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Edmonds, James A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-08-01

    We demonstrate the effectiveness of a new method for quantifying radiative forcing from land use and land cover change (LULCC) within an integrated assessment model, the Global Change Assessment Model (GCAM). The method relies on geographically differentiated estimates of radiative forcing from albedo change associated with major land cover transitions derived from the Community Earth System Model. We find that conversion of 1 km² of woody vegetation (forest and shrublands) to non-woody vegetation (crops and grassland) yields between 0 and –0.71 nW/m² of globally averaged radiative forcing determined by the vegetation characteristics, snow dynamics, and atmospheric radiation environment characteristic within each of 151 regions we consider globally. Across a set of scenarios designed to span a range of potential future LULCC, we find LULCC forcing ranging from –0.06 to –0.29 W/m² by 2070 depending on assumptions regarding future crop yield growth and whether climate policy favors afforestation or bioenergy crops. Inclusion of this previously uncounted forcing in the policy targets driving future climate mitigation efforts leads to changes in fossil fuel emissions on the order of 1.5 PgC/yr by 2070 for a climate forcing limit of 4.5 Wm–2, corresponding to a 12–67 % change in fossil fuel emissions depending on the scenario. Scenarios with significant afforestation must compensate for albedo-induced warming through additional emissions reductions, and scenarios with significant deforestation need not mitigate as aggressively due to albedo-induced cooling. In all scenarios considered, inclusion of albedo forcing in policy targets increases forest and shrub cover globally.

  15. 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.

  16. 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.

  17. 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.

  18. Numerical Modeling of Debris Flow Force Caused by Climate Change and Its application to Check Dam

    Science.gov (United States)

    KIM, S. D.; Jun, K.; JUN, B. H.; Lee, H. J.; TAK, W. J.

    2016-12-01

    Due to global warming, climate change cause a super hurricane and heavy rainfall frequently. Heavy rainfall cause by debris flow in mountainous terrains, and disasters by debris flow force have continuously increased. The purpose of this study is to analyze the characteristics of debris flow force acting on the check dam. The numerical approach to the debris flow force was performed by the Finite Difference Method (FDM) based on the erosion-deposition combination model including the equation of continuity, mass conservation, and momentum conservation. In order to investigate behavior of the debris flow force according to the variance of supplying water discharge and channel slope angle, a rectangular straight channel and one closed type check dam was set up for conducting numerical simulations. As the supply water discharges increase, the curve of the impact force by debris flow becomes unstable and fluctuation with high impact force occurred as time passes. And the peak impact force showed a steeper slope and appeared more quickly, the high impact force undergoes a fluctuation with high speed, and acting on the check dam. At the mountainous upstream, strong rainfall energy provoke a repeat erosion and deposition which results in debris flow force causing much damage along the check dam at the mountainous place. The analyses of the present study help provide information to predict future debris flow force and how to design for the check dam. This research was supported by a grant [MPSS-NH-2014-74] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government

  19. Global analysis of radiative forcing from fire-induced shortwave albedo change

    Directory of Open Access Journals (Sweden)

    G. López-Saldaña

    2014-05-01

    Full Text Available Land surface albedo, a key parameter to derive Earth's surface energy balance, is used in the parameterization of numerical weather prediction, climate monitoring and climate change impact assessments. Changes in albedo due to fire have not been fully investigated at continental and global scale. The main goal of this study therefore, is to quantify the changes in albedo produced by biomass burning activities and their associated shortwave radiative forcing. The study relies on the Moderate Resolution Imaging Spectroradiometer (MODIS MCD64A1 burned area product to create an annual composite of areas affected by fire and the MCD43C2 BRDF-Albedo snow-free product to compute a bihemispherical reflectance time series. The approximate day of burn is used to calculate the instantaneous change in shortwave Albedo. Using the corresponding National Centers for Environmental Prediction (NCEP monthly mean downward solar radiation flux at the surface, the global radiative forcing associated to fire was computed. The analysis reveals a mean decrease in shortwave albedo of −0.023 (1σ = 0.018 causing a mean positive radiative forcing of 6.31 W m–2 (1σ = 5.04 over the 2002–2012 time period in areas affected by fire. The greatest drop in mean shortwave albedo change occurs in 2002, which corresponds to the highest total area burnt (3.66 Mha observed in the same year and produces the highest mean radiative forcing (6.75 W m–2. Africa is the main contributor in terms of burned area but forests globally are giving the highest radiative forcing per unit area, thus give detectable changes in shortwave albedo. The global mean radiative forcing for the whole studied period ~ 0.04 W m–2 shows that the contribution of fires into the Earth system is not insignificant.

  20. Influence of external forcings on abrupt millennial-scale climate changes: a statistical modelling study

    Science.gov (United States)

    Mitsui, Takahito; Crucifix, Michel

    2016-07-01

    The last glacial period was punctuated by a series of abrupt climate shifts, the so-called Dansgaard-Oeschger (DO) events. The frequency of DO events varied in time, supposedly because of changes in background climate conditions. Here, the influence of external forcings on DO events is investigated with statistical modelling. We assume two types of simple stochastic dynamical systems models (double-well potential-type and oscillator-type), forced by the northern hemisphere summer insolation change and/or the global ice volume change. The model parameters are estimated by using the maximum likelihood method with the NGRIP Ca^{2+} record. The stochastic oscillator model with at least the ice volume forcing reproduces well the sample autocorrelation function of the record and the frequency changes of warming transitions in the last glacial period across MISs 2, 3, and 4. The model performance is improved with the additional insolation forcing. The BIC scores also suggest that the ice volume forcing is relatively more important than the insolation forcing, though the strength of evidence depends on the model assumption. Finally, we simulate the average number of warming transitions in the past four glacial periods, assuming the model can be extended beyond the last glacial, and compare the result with an Iberian margin sea-surface temperature (SST) record (Martrat et al. in Science 317(5837): 502-507, 2007). The simulation result supports the previous observation that abrupt millennial-scale climate changes in the penultimate glacial (MIS 6) are less frequent than in the last glacial (MISs 2-4). On the other hand, it suggests that the number of abrupt millennial-scale climate changes in older glacial periods (MISs 6, 8, and 10) might be larger than inferred from the SST record.

  1. Change management in pharmacy: a simulation game and pharmacy leaders' rating of 35 barriers to change.

    Science.gov (United States)

    Guérin, Aurélie; Lebel, Denis; Hall, Kevin; Bussières, Jean-François

    2015-12-01

    The primary objective was to rank barriers to change in pharmacy practice. Our secondary objective was to create a simulation game to stimulate reflection and discussion on the topic of change management. The game was created by the authors and used during a symposium attended by 43 hospital pharmacy leaders from all regions of Canada (Millcroft Conference, Alton, Ontario, June 2013). The main theme of the conference was 'managing change'. The simulation game, the rating of 35 barriers to change and the discussion that followed provided an opportunity for hospital pharmacy leaders to reflect on potential barriers to change, and how change might be facilitated through the use of an organized approach to change, such as that described in Kotter's eight-step model. This simulation game, and the associated rating of barriers to change, provided an opportunity for a group of hospital pharmacy leaders in Canada to reflect on the challenges associated with managing change in the healthcare setting. This simulation game can be modified and used by pharmacy practitioners in other countries to help identify and rank barriers to change in their particular pharmacy practice setting. © 2015 Royal Pharmaceutical Society.

  2. Resolving the phasing and forcing dynamics between North Atlantic climate and deep ocean circulation changes

    Science.gov (United States)

    Irvali, Nil; Ninnemann, Ulysses S.; Kleiven, Helga (Kikki) F.; Haflidason, Haflidi; Mjell, Tor L.

    2017-04-01

    Multidecadal changes in North Atlantic climate (e.g., AMO/AMV) have been attributed to changes in the Atlantic Meridional Overturning Circulation (AMOC) and suggested as a driver of overturning changes. While simulations find an in-phase relationship when AMOC modulates basin-wide climate, AMOC lags when basin scale climate is forced externally (e.g., volcanoes and solar). Unfortunately the observational records are too short to assess these multi-decadal scale dynamics. The surface climate reconstructions, based on annually resolved archives, have excellent time control raising the possibility for precise determination of phasing with other well dated records. Yet, all currently available reconstructions of deep ocean circulation have radiometric based age models; with inherent errors (±30-50 years minimum) preventing the determination of the absolute phasing between deep ocean circulation changes and AMO/AMV. In order to reduce these uncertainties we use stratigraphical appearance, abundance and geochemical composition of tephra grains from a high sedimentation rate site off the Gardar Drift, south of Iceland (GS06-144-09MC-D; 60˚ 19'N, 23˚ 58'W, 2081 m water depth). Identifying tephra layers (and their association) in the core and fingerprinting with known volcanic eruptions on Iceland provides absolute age markers. Combining these age markers with 210Pb and 14C AMS dates within the same core, we have built a new chronology for the core GS06-144-09MC-D. Changes in surface ocean hydrography and climate are further portrayed using planktonic foraminiferal δ18O, assemblage counts, modern analog technique derived sea surface temperatures and Mg/Ca paleothermometry. Records of Iceland Scotland Overflow Water (ISOW) vigor (Sortable Silt mean grain size; Mjell et al., 2016) and benthic carbon isotopes from the same core allow us to determine the absolute phasing between changes in basin-wide climate, deep ocean circulation, and deep water carbon chemistry spanning

  3. Maximum orbit plane change with heat-transfer-rate considerations

    Science.gov (United States)

    Lee, J. Y.; Hull, D. G.

    1990-01-01

    Two aerodynamic maneuvers are considered for maximizing the plane change of a circular orbit: gliding flight with a maximum thrust segment to regain lost energy (aeroglide) and constant altitude cruise with the thrust being used to cancel the drag and maintain a high energy level (aerocruise). In both cases, the stagnation heating rate is limited. For aeroglide, the controls are the angle of attack, the bank angle, the time at which the burn begins, and the length of the burn. For aerocruise, the maneuver is divided into three segments: descent, cruise, and ascent. During descent the thrust is zero, and the controls are the angle of attack and the bank angle. During cruise, the only control is the assumed-constant angle of attack. During ascent, a maximum thrust segment is used to restore lost energy, and the controls are the angle of attack and bank angle. The optimization problems are solved with a nonlinear programming code known as GRG2. Numerical results for the Maneuverable Re-entry Research Vehicle with a heating-rate limit of 100 Btu/ft(2)-s show that aerocruise gives a maximum plane change of 2 deg, which is only 1 deg larger than that of aeroglide. On the other hand, even though aerocruise requires two thrust levels, the cruise characteristics of constant altitude, velocity, thrust, and angle of attack are easy to control.

  4. Theoretical rates of pulsation period change in the Galactic Cepheids

    CERN Document Server

    Fadeyev, Yuri A

    2014-01-01

    Theoretical estimates of the rates of radial pulsation period change in Galactic Cepheids with initial masses 5.5M_\\odot <= Mzams <= 13M_\\odot, chemical composition X=0.7, Z=0.02 and periods 1.5 day <= P <= 100 day are obtained from consistent stellar evolution and nonlinear stellar pulsation computations. Pulsational instability was investigated for three crossings of the instability strip by the evolutionary track in the HR diagram. The first crossing occurs at the post-main sequence helium core gravitational contraction stage which proceeds in the Kelvin--Helmholtz timescale whereas the second and the third crossings take place at the evolutionary stage of thermonuclear core helium burning. During each crossing of the instability strip the period of radial pulsations is a quadratic function of the stellar evolution time. Theoretical rates of the pulsation period change agree with observations but the scatter of observational estimates of dP/dt noticeably exceeds the width of the band (\\delta\\lo...

  5. The rate of period change in DAV stars

    Science.gov (United States)

    Chen, Yan-Hui; Ding, Cai-Yun; Na, Wei-Wei; Shu, Hong

    2017-07-01

    Grids of DAV star models are evolved by WDEC, taking the element diffusion effect into account. The grid parameters are hydrogen mass {log}({M}{{H}}/{M}* ), helium mass log({M}{{He}}/{M}* ), stellar mass {M}* and effective temperature {T}{{eff}} for DAV stars. The core compositions are from white dwarf models evolved by MESA. Therefore, DAV star models evolved by WDEC have historically viable core compositions. Based on those DAV star models, we studied the rate of period change (\\dot{P}(k)) for different values of H, He, {M}* and {T}{{eff}}. The results are consistent with previous work. Two DAV stars G117-B15A and R548 have been observed for around 40 years. The rates of period change of two large-amplitude modes were obtained through the O - C method. We conducted an asteroseismological study on the two DAV stars and then obtained a best-fitting model for each star. Based on the two best-fitting models, the mode identifications (l, k) of the observed modes for G117-B15A and R548 are consistent with previous work. Both the observed modes and the observed \\dot{P}s can be fitted by calculated ones. The results indicate that our method of evolving DAV star models is feasible.

  6. 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...

  7. 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.

  8. Changes in gluteal muscle forces with alteration of footstrike pattern during running.

    Science.gov (United States)

    Vannatta, Charles Nathan; Kernozek, Thomas W; Gheidi, Naghmeh

    2017-08-09

    Gait retraining is a common form of treatment for running related injuries. Proximal factors at the hip have been postulated as having a role in the development of running related injuries. How altering footstrike affects hip muscles forces and kinematics has not been described. Thus, we aimed to quantify differences in hip muscle forces and hip kinematics that may occur when healthy runners are instructed to alter their foot strike pattern from their habitual rear-foot strike to a forefoot strike. This may gain insight on the potential etiology and treatment methods of running related lower extremity injury. Twenty-five healthy female runners completed a minimum of 10 running trials in a controlled laboratory setting under rear-foot strike and instructed forefoot strike conditions. Kinetic and kinematic data were used in an inverse dynamic based static optimization to estimate individual muscle forces during running. Within subject differences were investigated using a repeated measures multi-variate analysis of variance. Peak gluteus medius and minimus and hamstring forces were reduced while peak gluteus maximus force was increased when running with an instructed forefoot strike pattern. Peak hip adduction, hip internal rotation, and heel-COM distance were also reduced. Therefore, instructing habitual rearfoot strike runners to run with a forefoot strike pattern resulted in changes in peak gluteal and hamstring muscle forces and hip kinematics. These changes may be beneficial to the development and treatment of running related lower extremity injury. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Side force formation mechanism and change law of TBM center cutter

    Institute of Scientific and Technical Information of China (English)

    夏毅敏; 田彦朝; 谭青; 侯禹蒙

    2016-01-01

    The center cutter of a hard rock tunnel boring machine (TBM) is installed on the cutterhead at a small radius and thus bears complex side force. Given this fact, the formation mechanism and change law of the side force suffered by the center cutter were studied. Based on the rock shear failure criterion in combination with the lateral rolling width, a model for predicting the average side force was set up. Besides, a numerical analysis model of the rock fragmentation of the center cutter was established, and the instantaneous load changing features were investigated. Results shows that the inner side of the center cutter can form lateral rolling annulus in rock during the rotary cutting process. The smaller the installation radius is, the greater the cutter side force will be. In a working condition, the side force of the innermost center cutter is 11.66 kN, while it decreases sharply when installation radius increases. Variation tends to be gentle when installation radius is larger than 500 mm, and the side force of the outermost center cutter is reduced to 0.74 kN.

  10. 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

  11. A transient climate change simulation with greenhouse gas and aerosol forcing: projected climate to the twenty-first century

    Energy Technology Data Exchange (ETDEWEB)

    Boer, G.J.; Flato, G.; Ramsden, D. [Canadian Centre for Climate Modelling and Analysis, Victoria, BC (Canada)

    2000-06-01

    The potential climatic consequences of increasing atmospheric greenhouse gas (GHG) concentration and sulfate aerosol loading are investigated for the years 1900 to 2100 based on five simulations with the CCCma coupled climate model. The five simulations comprise a control experiment without change in GHG or aerosol amount, three independent simulations with increasing GHG and aerosol forcing, and a simulation with increasing GHG forcing only. Climate warming accelerates from the present with global mean temperatures simulated to increase by 1.7 C to the year 2050 and by a further 2.7 C by the year 2100. The warming is nonuniform as to hemisphere, season, and underlying surface. Changes in interannual variability of temperature show considerable structure and seasonal dependence. The effect of the comparatively localized negative radiative forcing associated with the aerosol is to retard and reduce the warming by about 0.9 C at 2050 and 1.2 C at 2100. Its primary effect on temperature is to counteract the global pattern of GHG-induced warming and only secondarily to affect local temperatures suggesting that the first order transient climate response of the system is determined by feedback processes and only secondarily by the local pattern of radiative forcing. The warming is accompanied by a more active hydrological cycle with increases in precipitation and evaporation rates that are delayed by comparison with temperature increases. There is an ''El Nino-like'' shift in precipitation and an overall increase in the interannual variability of precipitation. The effect of the aerosol forcing is again primarily to delay and counteract the GHG-induced increase. Decreases in soil moisture are common but regionally dependent and interannual variability changes show considerable structure. (orig.)

  12. CLIMATE CHANGE. Long-term climate forcing by atmospheric oxygen concentrations.

    Science.gov (United States)

    Poulsen, Christopher J; Tabor, Clay; White, Joseph D

    2015-06-12

    The percentage of oxygen in Earth's atmosphere varied between 10% and 35% throughout the Phanerozoic. These changes have been linked to the evolution, radiation, and size of animals but have not been considered to affect climate. We conducted simulations showing that modulation of the partial pressure of oxygen (pO2), as a result of its contribution to atmospheric mass and density, influences the optical depth of the atmosphere. Under low pO2 and a reduced-density atmosphere, shortwave scattering by air molecules and clouds is less frequent, leading to a substantial increase in surface shortwave forcing. Through feedbacks involving latent heat fluxes to the atmosphere and marine stratus clouds, surface shortwave forcing drives increases in atmospheric water vapor and global precipitation, enhances greenhouse forcing, and raises global surface temperature. Our results implicate pO2 as an important factor in climate forcing throughout geologic time.

  13. Change of Job and Change of Residence - Geographical Mobility of the Labour Force

    DEFF Research Database (Denmark)

    Deding, Mette; Filges, Trine

    Solving regional labour market discrepancies through geographical mobility has gained increased political interest. The decision of changing job is closely related to the decision of changing residence as either change may imply a change in commuting cost. In this paper we set up a search model...

  14. Change of Job and Change of Residence - Geographical Mobility of the Labour Force

    DEFF Research Database (Denmark)

    Deding, Mette; Filges, Trine

    Solving regional labour market discrepancies through geographical mobility has gained increased political interest. The decision of changing job is closely related to the decision of changing residence as either change may imply a change in commuting cost. In this paper we set up a search model...... that can explain the residence and job changing behaviour of workers. The model is a double search model, in the sense that workers search for better jobs and dwellings simultaneously. Results show that the interrelationship between change of job and change of residence is very complex. However, scope...

  15. Resistance to alveolar shape change limits range of force propagation in lung parenchyma.

    Science.gov (United States)

    Ma, Baoshun; Smith, Bradford J; Bates, Jason H T

    2015-06-01

    We have recently shown that if the lung parenchyma is modeled in 2 dimensions as a network of springs arranged in a pattern of repeating hexagonal cells, the distortional forces around a contracting airway propagate much further from the airway wall than classic continuum theory predicts. In the present study we tested the hypothesis that this occurs because of the negligible shear modulus of a hexagonal spring network. We simulated the narrowing of an airway embedded in a hexagonal network of elastic alveolar walls when the hexagonal cells of the network offered some resistance to a change in shape. We found that as the forces resisting shape change approach about 10% of the forces resisting length change of an individual spring the range of distortional force propagation in the spring network fell of rapidly as in an elastic continuum. We repeated these investigations in a 3-dimensional spring network composed of space-filling polyhedral cells and found similar results. This suggests that force propagation away from a point of local parenchymal distortion also falls off rapidly in real lung tissue. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Beyond the Hookean Spring Model: Direct Measurement of Optical Forces Through Light Momentum Changes.

    Science.gov (United States)

    Farré, Arnau; Marsà, Ferran; Montes-Usategui, Mario

    2017-01-01

    The ability to measure forces in the range of 0.1-100 pN is a key feature of optical tweezers used for biophysical and cell biological studies. Analysis of the interactions between biomolecules and the forces that biomolecular motors generate at the single-molecule level has provided valuable insights in the molecular mechanisms that govern key cellular functions such as gene expression and the long-distance transport of organelles. Methods for determining the minute forces that biomolecular motors generate exhibit notable constraints that limit their application for studies other than the well-controlled in vitro experiments (although recent advances have been made that permit more quantitative optical tweezers studies insight living cells). One constraint comes from the linear approximation of the distance vs. force relationship used to extract the force from the position of the bead in the trap. This commonly employed "indirect" approach, although usually sufficiently precise, restricts the use of optical tweezers to a limited range of displacements (typically up to ±150 nm for small beads). Measurements based on the detection of the light-momentum changes, on the other hand, offer a "direct" and precise way to determine forces even when the generated displacements reach the escape point, thus covering the complete force range developed by the trap. In this chapter, we detail the requirements for the design of a force-sensor instrument based on light-momentum changes using a high-numerical-aperture objective lens and provide insights into its construction. We further discuss the calibration of the system and the main steps for its routine operation.

  17. Why must a solar forcing be larger than a CO2 forcing to cause the same global mean surface temperature change?

    Science.gov (United States)

    Modak, Angshuman; Bala, Govindasamy; Cao, Long; Caldeira, Ken

    2016-04-01

    Many previous studies have shown that a solar forcing must be greater than a CO2 forcing to cause the same global mean surface temperature change but a process-based mechanistic explanation is lacking in the literature. In this study, we investigate the physical mechanisms responsible for the lower efficacy of solar forcing compared to an equivalent CO2 forcing. Radiative forcing is estimated using the Gregory method that regresses top-of-atmosphere (TOA) radiative flux against the change in global mean surface temperature. For a 2.25% increase in solar irradiance that produces the same long term global mean warming as a doubling of CO2 concentration, we estimate that the efficacy of solar forcing is ∼80% relative to CO2 forcing in the NCAR CAM5 climate model. We find that the fast tropospheric cloud adjustments especially over land and stratospheric warming in the first four months cause the slope of the regression between the TOA net radiative fluxes and surface temperature to be steeper in the solar forcing case. This steeper slope indicates a stronger net negative feedback and hence correspondingly a larger solar forcing than CO2 forcing for the same equilibrium surface warming. Evidence is provided that rapid land surface warming in the first four months sets up a land-sea contrast that markedly affects radiative forcing and the climate feedback parameter over this period. We also confirm the robustness of our results using simulations from the Hadley Centre climate model. Our study has important implications for estimating the magnitude of climate change caused by volcanic eruptions, solar geoengineering and past climate changes caused by change in solar irradiance such as Maunder minimum.

  18. Distinct global warming rates tied to multiple ocean surface temperature changes

    Science.gov (United States)

    Yao, Shuai-Lei; Luo, Jing-Jia; Huang, Gang; Wang, Pengfei

    2017-07-01

    The globally averaged surface temperature has shown distinct multi-decadal fluctuations since 1900, characterized by two weak slowdowns in the mid-twentieth century and early twenty-first century and two strong accelerations in the early and late twentieth century. While the recent global warming (GW) hiatus has been particularly ascribed to the eastern Pacific cooling, causes of the cooling in the mid-twentieth century and distinct intensity differences between the slowdowns and accelerations remain unclear. Here, our model experiments with multiple ocean sea surface temperature (SST) forcing reveal that, although the Pacific SSTs play essential roles in the GW rates, SST changes in other basins also exert vital influences. The mid-twentieth-century cooling results from the SST cooling in the tropical Pacific and Atlantic, which is partly offset by the Southern Ocean warming. During the recent hiatus, the tropical Pacific-induced strong cooling is largely compensated by warming effects of other oceans. In contrast, during the acceleration periods, ubiquitous SST warming across all the oceans acts jointly to exaggerate the GW. Multi-model simulations with separated radiative forcing suggest diverse causes of the SST changes in multiple oceans during the GW acceleration and slowdown periods. Our results highlight the importance of multiple oceans on the multi-decadal GW rates.

  19. A constant-force technique to measure corneal biomechanical changes after collagen cross-linking.

    Directory of Open Access Journals (Sweden)

    Olivier Richoz

    Full Text Available PURPOSE: To introduce a constant-force technique for the analysis of corneal biomechanical changes induced after collagen cross-linking (CXL that is better adapted to the natural loading in the eye than previous methods. METHODS: For the biomechanical testing, a total of 50 freshly enucleated eyes were obtained and subdivided in groups of 5 eyes each. A Zwicki-Line Testing Machine was used to analyze the strain of 11 mm long and 5 mm wide porcine corneal strips, with and without CXL. Before material testing, the corneal tissues were pre-stressed with 0.02 N until force stabilization. Standard strip extensiometry was performed as control technique. For the constant-force technique, tissue elongation (Δ strain, % was analyzed for 180 seconds while different constant forces (0.25 N, 0.5 N, 1 N, 5 N were applied. RESULTS: Using a constant force of 0.5 N, we observed a significant difference in Δstrain between 0.26±0.01% in controls and 0.12±0.03% in the CXL-treated group (p = 0.003 over baseline. Similarly, using a constant force of 1 N, Δstrain was 0.31±0.03% in controls and 0.19±0.02% after CXL treatment (p = 0.008. No significant differences were observed between CXL-treated groups and controls with 0.25 N or 5 N constant forces. Standard stress-strain extensiometry failed to show significant differences between CXL-treated groups and controls at all percentages of strains tested. CONCLUSION: We propose a constant-force technique to measure corneal biomechanics in a more physiologic way. When compared to standard stress-strain extensiometry, the constant-force technique provides less variability and thus reaches significant results with a lower sample number.

  20. 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.

  1. Association of Fetal Heart Rate Baseline Change and Neonatal Outcomes.

    Science.gov (United States)

    Yang, Michael; Stout, Molly J; López, Julia D; Colvin, Ryan; Macones, George A; Cahill, Alison G

    2017-07-01

    Objective The objective of this study was to describe the incidence of baseline change within normal range during labor and its prediction of neonatal outcomes. Materials and Methods This was a prospective cohort of singleton, nonanomalous, term neonates with continuous electronic fetal monitoring and normal baseline fetal heart rate throughout the last 2 hours of labor. We determined baseline in 10-minute segments using Eunice Kennedy Shriver National Institute of Child Health and Human Development criteria. We evaluated baseline changes of ≥ 20 and ≥ 30 bpm for association with acidemia (umbilical cord arterial pH ≤ 7.10) and neonatal intensive care unit (NICU) admission. Finally, we performed a sensitivity analysis of normal neonates, excluding those with acidemia, NICU admission, or 5-minute Apgar bpm; 272 (9.0%) had ≥ 30 bpm. Among normal neonates (n = 2,939), 1,221 (41.5%) had change ≥20 bpm. Acidemia was not associated with baseline change of any direction or magnitude. NICU admission was associated with decrease ≥ 20 bpm (adjusted odds ratio [aOR]: 2.93; 95% confidence interval [CI]: 1.19 - 7.21) or any direction ≥ 20 bpm (aOR: 4.06; 95% CI: 1.46-11.29). For decrease ≥ 20 bpm, sensitivity and specificity were 40.0 and 81.7%; for any direction ≥ 20 bpm, 75.0 and 58.3%. Conclusion Changes of normal baseline are common in term labor and poorly predict morbidity, regardless of direction or magnitude. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  2. Experimental evidence of dynamic re-organization of evolving landscapes under changing climatic forcing

    Science.gov (United States)

    Singh, Arvind; Tejedor, Alejandro; Zaliapin, Ilya; Reinhardt, Liam; Foufoula-Georgiou, Efi

    2015-04-01

    The aim of this study is to better understand the dynamic re-organization of an evolving landscape under a scenario of changing climatic forcing for improving our knowledge of geomorphic transport laws under transient conditions and developing predictive models of landscape response to external perturbations. Real landscape observations for long-term analysis are limited and to this end a high resolution controlled laboratory experiment was conducted at the St. Anthony Falls laboratory at the University of Minnesota. Elevation data were collected at temporal resolution of 5 mins and spatial resolution of 0.5 mm as the landscape approached steady state (constant uplift and precipitation rate) and in the transient state (under the same uplift and 5x precipitation). The results reveal rapid topographic re-organization under a five-fold precipitation increase with the fluvial regime expanding into the previously debris dominated regime, accelerated erosion happening at hillslope scales, and rivers shifting from an erosion-limited to a transport-limited regime. From a connectivity and clustering analysis of the erosional and depositional events, we demonstrate the strikingly different spatial patterns of landscape evolution under steady-state (SS) and transient-state (TS), even when the time under SS is "stretched" compared to that under TS such as to match the total volume and PDF of erosional and depositional amounts. We quantify the spatial coupling of hillslopes and channels and demonstrate that hillslopes lead and channels follow in re-organizing the whole landscape under such an amplified precipitation regime.

  3. Driving forces of main landscape change processes from past 200 years in Central Europe - differences between old democratic and post-socialist countries

    Directory of Open Access Journals (Sweden)

    Skokanová Hana

    2016-03-01

    Full Text Available The article compares and points out differences in driving forces of four main landscape change processes that shaped post-socialist countries and old democratic countries of Central Europe during the last two centuries. Studying landscape change processes and corresponding driving forces helps in understanding patterns of present landscape and can help among others in better prediction of future landscape change trends. Here, the presented results are based on review of scientific articles published in peer-reviewed journals between 2000 and 2014. Driving forces affecting these processes were grouped into four categories. Economic forces drove mainly agricultural intensification; agricultural land abandonment and urbanisation and were pronounced especially in the second half of the 20th century and at the beginning of the 21st century. Technological driving forces affected agricultural intensification especially in the 19th century and the second half of the 20th century while cultural driving forces had the biggest impact on urbanisation at the beginning of the 21st century. Political driving forces affected agricultural intensification, urbanisation as well as agricultural land abandonment and were pronounced mainly during the second half of the 20th century in the post-socialist countries. Political forces in the form of subsidies drove agricultural extensification at the beginning of the 21st century. The drivers for the agricultural intensification as well as urbanisation seem to be similar for both old democratic and post-socialist countries. In contrast, agricultural land abandonment in the old democratic countries was driven by technological, cultural and economic driving forces while in the post-socialist countries the political driving forces were mainly responsible. Changes in systems for subsidies and changes in the agricultural commodity markets are also responsible for different frequencies and rates of extensification of

  4. Development of Productive Forces and the Changes of Rural President’s Consumption Concept

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The developmental status of productivity in Chinese rural area is introduced. Since the implementation of the agriculture supporting policies in 2004, the productive forces in rural areas have been improved greatly. It is reflected on the following aspects: great enhancement of rural labors’ cultural quality; the quantity of agricultural machines has been increased; the level of production management and decision has been increased greatly. The paper analyzes the promotion role played by the development of productive forces to rural residents’ consumption conception. The development of productive forces has laid a solid foundation for changing rural residents’ consumption concept; changed rural residents’ consumption structure and improved the socialized degree of rural residents’ consumption. Countermeasures on cultivating new consumption fields in rural areas are put forward including leading rural residents to foster the modern consumption conception; intensifying the governmental support and leading rural residents to set up healthy consumption concept.

  5. Effects of different regional climate model resolution and forcing scales on projected hydrologic changes

    Science.gov (United States)

    Mendoza, Pablo A.; Mizukami, Naoki; Ikeda, Kyoko; Clark, Martyn P.; Gutmann, Ethan D.; Arnold, Jeffrey R.; Brekke, Levi D.; Rajagopalan, Balaji

    2016-10-01

    We examine the effects of regional climate model (RCM) horizontal resolution and forcing scaling (i.e., spatial aggregation of meteorological datasets) on the portrayal of climate change impacts. Specifically, we assess how the above decisions affect: (i) historical simulation of signature measures of hydrologic behavior, and (ii) projected changes in terms of annual water balance and hydrologic signature measures. To this end, we conduct our study in three catchments located in the headwaters of the Colorado River basin. Meteorological forcings for current and a future climate projection are obtained at three spatial resolutions (4-, 12- and 36-km) from dynamical downscaling with the Weather Research and Forecasting (WRF) regional climate model, and hydrologic changes are computed using four different hydrologic model structures. These projected changes are compared to those obtained from running hydrologic simulations with current and future 4-km WRF climate outputs re-scaled to 12- and 36-km. The results show that the horizontal resolution of WRF simulations heavily affects basin-averaged precipitation amounts, propagating into large differences in simulated signature measures across model structures. The implications of re-scaled forcing datasets on historical performance were primarily observed on simulated runoff seasonality. We also found that the effects of WRF grid resolution on projected changes in mean annual runoff and evapotranspiration may be larger than the effects of hydrologic model choice, which surpasses the effects from re-scaled forcings. Scaling effects on projected variations in hydrologic signature measures were found to be generally smaller than those coming from WRF resolution; however, forcing aggregation in many cases reversed the direction of projected changes in hydrologic behavior.

  6. 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...

  7. EXTERNAL FORCES DRIVING CHANGE IN THE ROMANIAN SMALL AND MEDIUM SIZED ENTERPRISES

    Directory of Open Access Journals (Sweden)

    Roiban Roxana Nadina

    2012-07-01

    Full Text Available Change is a constant in everyday life confronting organizations to continuously adapt their strategy, structure, processes, and culture in order to survive and stay competitive on the market. Implementing organizational change is one of the most important skills required for managers and in the meantime the most difficult one. The forces driving change within an organization, that can be either external or internal, are those that propel a company forward towards change and in order to identify the need for change and make the proper changes, managers have to develop a tool that allows them to analyze how does the environment influence their business activities. A vision for change will clarify the directions in which the organization needs to move, starting from its current state and taking in consideration the existing opportunities and threats from the environment that allow to move to a future desired state. The purpose of this paper is to identify the concern for change in the Romanian small and medium sized enterprises by presenting and explaining the past and present influences of the main external forces that have determined the need for change in the last 3-5 years and to make recommendations about future possible changes that have to be performed by managers for a better harmonization with the environment. The research method used for this study is the interview on a sample that contains some of the most relevant SME’s from the western side of Romania, from different industries. We analyzed the main external forces that had an impact on the small and medium sized enterprises and how were they generating the need for organizational change, in order to see which present and future changes are required.

  8. MODELS OF THE 5 PORTERS COMPETITIVE FORCES METHODOLOGY CHANGES IN COMPANIES STRATEGY DEVELOPMENT ON COMPETITIVE MARKET

    Directory of Open Access Journals (Sweden)

    Sergey I Zubin

    2014-01-01

    Full Text Available There are some different types of approaches to 5 Porters Forces model development in thisarticle. Authors take up the negative attitude researcher reasons to this instrument and inputsuch changes in it, which can help to fi nd the best way to companies growing up on competitive market.

  9. 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.

  10. Cultural Changes Required in the Army to Truly Achieve a Total Force

    Science.gov (United States)

    2016-02-16

    AIR WAR COLLEGE AIR UNIVERSITY CULTURAL CHANGES REQUIRED IN THE ARMY TO TRULY ACHIEVE A TOTAL FORCE by John Gobrick, LTC...and Army Reserve need to act now and implement enduring cultural changes . Leaders must invest the time and effort to address the underlying cultural...employment, technicians are required to have a simultaneous membership in the Army Reserve , typically in the same unit. The vast majority of Army

  11. Determination of Rate of Hearing Changes After Spinal Anesthesia

    Directory of Open Access Journals (Sweden)

    F Omidi

    2008-07-01

    Full Text Available Introduction: Hearing loss after surgery is reported rarely. Its prevalence rate is different and reported to be between 3-92%. Hearing loss is often subclinical and not diagnosed without audiometry. The aim of this study was to determine rate of hearing changes after spinal anesthesia in patients undergoing surgery with spinal anesthesia. Methods: In this descriptive study, forty male patients scheduled for repair of inguinal hernia under spinal anesthesia were selected by simple sampling method. Before surgery, audiometry was performed for both the ears of the patients. Audiomatery was performed again by the audiometry specialist on day one, five, fifteen and two months after surgery. Results: Hearing loss was observed in 13 (32.5% patients. Hearing loss in 12 patients (92% was in low hearing frequency range and 1 patient (8% was in mid hearing frequency. Hearing loss in 8 patients (61% was ipsilateral and in 5 patients (39% was bilateral. Hearing loss in 9 patients (69% on 5th day and 2 patients (5/15% on 15th day resolved spontaneously. Conclusion: Results of this study conformed that hearing loss after spinal anesthesia is not a serious problem and can resolve spontaneously. It seems that there is relationship between hearing loss and headache.

  12. Seismic Rate Changes Associated with Seasonal, Annual, and Decadal Changes in the Cryosphere

    Science.gov (United States)

    Sauber-Rosenberg, Jeanne

    2012-01-01

    Near the Bering Glacier Global Fiducial site in southern Alaska large cryospheric fluctuations occur in a region of upper crustal faulting and folding associated with collision and accretion of the Yakutat terrane. In this study we report constraints on seasonal, annual and decadal cryospheric changes estimated over the last decade from field, aircraft and satellite measurements, and we evaluate the influence of cryospheric changes on the background seismic rate. Multi-year images from the Bering Glacier global fiducial site are available since mid-2003 to constrain changes in extent of the Bering Glacier and to discern feature changes in the glacial surface. Starting around the same time, satellite gravimetric measurements from the Gravity Recovery and Climate experiment (GRACE) commenced. Large spatial-scale mass change calculated from the GRACE 1deg x 1deg mascon solution of Luthcke et al. [2012] indicate a general trend of annual ice mass loss for southern Alaska but with large, variable seasonal mass fluctuations. Since 2007, the station position of a continuous GPS site near Cape Yakataga (Alaska EarthScope PBO site, AB35) has been available as well. In addition to changes in the geodetic position due to tectonic motion, this GPS station shows large seasonal excursions in the detrended vertical and horizontal position components consistent with snow loading in the fall and winter and melt onset/mass decrease in the spring/summer. To better understand the timing of processes responsible for the onset of cryospheric mass loss documented in the GRACE data, we examined changes in the snow cover extent and the onset of melt in the spring. We calculated the surface displacements of the solid Earth and theoretical earthquake failure criteria associated with these annual and seasonal ice and snow changes using layered elastic half-space. Additionally, we compared the seismic rate (M>1.8) from a reference background time period against other time periods with variable

  13. 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.

  14. 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.

  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. Propagation of the state change induced by external forces in local interactions

    Science.gov (United States)

    Lu, Jianjun; Tokinaga, Shozo

    2016-10-01

    This paper analyses the propagation of the state changes of agents that are induced by external forces applied to a plane. In addition, we propose two models for the behavior of the agents placed on a lattice plane, both of which are affected by local interactions. We first assume that agents are allowed to move to another site to maximise their satisfaction. Second, we utilise a model in which the agents choose activities on each site. The results show that the migration (activity) patterns of agents in both models achieve stability without any external forces. However, when we apply an impulsive external force to the state of the agents, we then observe the propagation of the changes in the agents' states. Using simulation studies, we show the conditions for the propagation of the state changes of the agents. We also show the propagation of the state changes of the agents allocated in scale-free networks and discuss the estimation of the agents' decisions in real state changes. Finally, we discuss the estimation of the agents' decisions in real state temporal changes using economic and social data from Japan and the United States.

  17. Detecting the influence of anthropogenic forcings on changes in the South Asian Monsoon subseasonal rainfall characteristics

    Science.gov (United States)

    Singh, D.; Bollasina, M. A.; Ting, M.; Diffenbaugh, N. S.

    2016-12-01

    Subseasonal variability of the South Asian summer monsoon leads to wet and dry spells that cause acute agricultural and societal impacts. Previous studies have documented changes in several subseasonal precipitation characteristics, including increases in dry-day frequency, dry-spell frequency, and wet-spell intensity. However, the causes of these historical changes remain poorly understood. We use rainfall observations and climate model simulations to identify the influence of individual natural and anthropogenic forcing agents on historical trends in wet and dry spells over the core-monsoon region during the peak-monsoon season (July-August). We show that aerosol forcing is not only the primary driver of seasonal rainfall trends, but also of changes in total number of dry days, dry-spell frequency and intensity, and wet-spell frequency. By suppressing mean seasonal rainfall but increasing daily variability, aerosol forcing leads to fewer wet spells, along with fewer, shorter, less-intense dry spells. Although greenhouse gases (GHGs) largely oppose the aerosol-induced changes, the aerosol imprint dominates the spatial changes in seasonal and subseasonal rainfall characteristics during the late 20th century. The dominant influence of aerosols on subseasonal wet and dry spells has important implications for efforts to simultaneously manage global GHGs and regional air quality and adapt to changes in climate in coming decades.

  18. Step-change in retreat rates on Novaya Zemlya outlet glaciers

    Science.gov (United States)

    Carr, Rachel; Bell, Heather; Killick, Rebecca; Holt, Tom

    2017-04-01

    Arctic ice masses have rapidly lost ice from the mid-1990s, through a combination of negative surface mass balance and accelerated ice discharge from marine-terminating outlet glaciers. In the past decade, substantial mass deficits have been identified on Novaya Zemlya (NVZ), Russian High Arctic, and its outlet glaciers began to retreat rapidly, from 2000 onwards. However, little is known about longer-term glacier behaviour on NVZ, meaning we have limited context for their recent acceleration in retreat. Here, we greatly extend the available record of glacier retreat, and assess multi-decadal glacier response to forcing between 1976 and 2015, using remotely sensed data. Using statistical changepoint analysis, we demonstrate a significant change in retreat rates for many glaciers, during the early 2000s. We also show that retreat slowed on numerous outlets from 2013 onwards, and that some glaciers even began to advance. NVZ glaciers have previously shown step-like changes in retreat rates, so we cannot determine whether this represents a longer-term trend or short-term slow-down, but it warrants future monitoring. We also assessed spatial patterns of retreat and found no significant differences in retreat rates according to coast or ice mass. Instead, the rate and temporal pattern of retreat were strongly dependant on terminus type: outlets terminating in lakes or the ocean retreated significantly faster than those ending on land. Interestingly, retreat rates on marine- and lake-terminating glaciers were not significantly different. However, the lake-terminating glaciers showed very little variation in retreat rates between glacier or over time, whereas the variability was very large on ocean-terminating glaciers. In terms of climatic controls, significant changes in Jul-Sep sea ice on both coasts of NVZ coincide with the onset of more rapid retreat, but there is large internnual variability in the data.

  19. 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

  20. Biomarkers of aging in women and the rate of longitudinal changes.

    Science.gov (United States)

    Ueno, Linda Massako; Yamashita, Yoshinori; Moritani, Toshio; Nakamura, Eitaro

    2003-01-01

    The purposes of this study were (1) to estimate biological age score (BAS) in Japanese healthy women based on the 4-7 years longitudinal data for physiological, hematological and biochemical examinations and (2) to examine the rate of aging changes in adult women based on the estimated BAS. The samples consisted of cross-sectional (n=981) and longitudinal (n=110) groups. Out of 31 variables examined, five variables (forced expiratory volume in 1.0 s, systolic blood pressure, mean corpuscular hemoglobin, glucose, albumin/globulin ratio) that met the following criteria: 1) significant cross-sectional correlation with age; 2) significant longitudinal change in the same direction as the cross-sectional correlation; and (3) assessment of redundancy, were selected as candidate biomarkers of aging. This variable set was then submitted into a principal component analysis, and the first principal component obtained from this analysis was used as an equation for assessing one's BAS. Individual BAS showed a high longitudinal stability of age-related changes, suggesting high predictive validity of our newly developed aging measurement equation. However, changes in the aging rate based on the estimated BAS were not constant. The mean slopes of the regression lines of BAS for the three age groups (agelongitudinal method used for selection of variables to compute the BAS was useful and theoretically valid compared to those obtained from cross-sectional data analysis.

  1. Creating a New Model for Mainstreaming Climate Change Adaptation for Critical Infrastructure: The New York City Climate Change Adaptation Task Force and the NYC Panel on Climate Change

    Science.gov (United States)

    Rosenzweig, C.; Solecki, W. D.; Freed, A. M.

    2008-12-01

    The New York City Climate Change Adaptation Task Force, launched in August 2008, aims to secure the city's critical infrastructure against rising seas, higher temperatures and fluctuating water supplies projected to result from climate change. The Climate Change Adaptation Task Force is part of PlaNYC, the city's long- term sustainability plan, and is composed of over 30 city and state agencies, public authorities and companies that operate the region's roads, bridges, tunnels, mass transit, and water, sewer, energy and telecommunications systems - all with critical infrastructure identified as vulnerable. It is one of the most comprehensive adaptation efforts yet launched by an urban region. To guide the effort, Mayor Michael Bloomberg has formed the New York City Panel on Climate Change (NPCC), modeled on the Intergovernmental Panel on Climate Change (IPCC). Experts on the panel include climatologists, sea-level rise specialists, adaptation experts, and engineers, as well as representatives from the insurance and legal sectors. The NPCC is developing planning tools for use by the Task Force members that provide information about climate risks, adaptation and risk assessment, prioritization frameworks, and climate protection levels. The advisory panel is supplying climate change projections, helping to identify at- risk infrastructure, and assisting the Task Force in developing adaptation strategies and guidelines for design of new structures. The NPCC will also publish an assessment report in 2009 that will serve as the foundation for climate change adaptation in the New York City region, similar to the IPCC reports. Issues that the Climate Change Adaptation Task Force and the NPCC are addressing include decision- making under climate change uncertainty, effective ways for expert knowledge to be incorporated into public actions, and strategies for maintaining consistent and effective attention to long-term climate change even as municipal governments cycle

  2. Changes in force production and stroke parameters of trained able-bodied and unilateral arm-amputee female swimmers during a 30 s tethered front-crawl swim.

    Science.gov (United States)

    Lee, Casey Jane; Sanders, Ross H; Payton, Carl J

    2014-01-01

    This study examined changes in the propulsive force and stroke parameters of arm-amputee and able-bodied swimmers during tethered swimming. Eighteen well-trained female swimmers (nine unilateral arm amputees and nine able-bodied) were videotaped performing maximal-effort 30 s front-crawl swims, while attached to a load cell mounted on a pool wall. Tether force, stroke rate, stroke phase durations and inter-arm angle were quantified. The able-bodied group produced significantly higher mean and maximum tether forces than the amputee group. The mean of the intra-cyclic force peaks was very similar for both groups. Mean and maximum tether force had significant negative associations with 100 m swim time, for both groups. Both groups exhibited a similar fatigue index (relative decrease in tether force) during the test, but the amputees had a significantly greater stroke rate decline. A significant positive association between stroke rate decline and fatigue index was obtained for the able-bodied group only. Inter-arm angle and relative phase durations did not change significantly during the test for either group, except the recovery phase duration of the arm amputees, which decreased significantly. This study's results can contribute to the development of a more evidence-based classification system for swimmers with a disability.

  3. 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.

  4. Disruptive Innovations as a Driving Force for the Change of Wireless Telecommunication Infrastructures

    DEFF Research Database (Denmark)

    Kyoseva, Tsvetoslava; Poulkov, Vladimir; Mihaylov, Mihail Rumenov

    2014-01-01

    Innovations are the driving force for fundamental changes and development of future generation telecommunication networks. When considering innovations as drivers for the development of next generation telecommunication networks an important question is whether an innovative emerging technology...... would cause a disruption requiring fundamental change of the infrastructure or will it will only catalyze its evolution. This paper describes the major characteristics of disruptive innovations as a driving force for fundamental changes in existing telecommunications infrastructures. By analyzing...... the current trends in mobile communications, we reason that the emergence of new telecommunication architectures and infrastructures is inevitable. An important consideration in the analysis is the driving role of disruptive technologies for the future of telecommunications. Based on a model for evaluating...

  5. 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

  6. Isolating the roles of different forcing agents in global stratospheric temperature changes using model integrations with incrementally added single forcings

    Science.gov (United States)

    Aquila, V.; Swartz, W. H.; Waugh, D. W.; Colarco, P. R.; Pawson, S.; Polvani, L. M.; Stolarski, R. S.

    2016-07-01

    Satellite instruments show a cooling of global stratospheric temperatures over the whole data record (1979-2014). This cooling is not linear and includes two descending steps in the early 1980s and mid-1990s. The 1979-1995 period is characterized by increasing concentrations of ozone-depleting substances (ODSs) and by the two major volcanic eruptions of El Chichón (1982) and Mount Pinatubo (1991). The 1995-present period is characterized by decreasing ODS concentrations and by the absence of major volcanic eruptions. Greenhouse gas (GHG) concentrations increase over the whole time period. In order to isolate the roles of different forcing agents in the global stratospheric temperature changes, we performed a set of simulations using the NASA Goddard Earth Observing System Chemistry-Climate Model with prescribed sea surface temperatures. We find that in our model simulations the cooling of the stratosphere from 1979 to present is mostly driven by changes in GHG concentrations in the middle and upper stratosphere and by GHG and ODS changes in the lower stratosphere. While the cooling trend caused by increasing GHGs is roughly constant over the satellite era, changing ODS concentrations cause a significant stratospheric cooling only up to the mid-1990s, when they start to decrease because of the implementation of the Montreal Protocol. Sporadic volcanic events and the solar cycle have a distinct signature in the time series of stratospheric temperature anomalies but do not play a statistically significant role in the long-term trends from 1979 to 2014. Several factors combine to produce the step-like behavior in the stratospheric temperatures: in the lower stratosphere, the flattening starting in the mid-1990s is due to the decrease in ozone-depleting substances; Mount Pinatubo and the solar cycle cause the abrupt steps through the aerosol-associated warming and the volcanically induced ozone depletion. In the middle and upper stratosphere, changes in solar

  7. A statistical modelling study of the abrupt millennial-scale climate changes focusing on the influence of external forcings

    CERN Document Server

    Mitsui, Takahito

    2015-01-01

    Dansgaard-Oeschger (DO) events are abrupt millennial-scale climate changes mainly detected in the North Atlantic region during the last glacial cycle. The frequency of the DO events varied in time, supposedly because of changes in background climate conditions. Here, we investigate the influences of external forcings on DO events with statistical modelling. We assume two types of generic stochastic dynamical systems models (double-well potential-type and oscillator-type), forced by the northern hemisphere summer insolation change and/or the global ice volume change. The models are calibrated by maximizing their likelihood and compared using the Bayesian Information Criterion (BIC). Among the models, the stochastic oscillator model forced by both insolation and ice volume changes is favored by the NGRIP calcium ion data. The BIC scores provide positive evidence for the ice volume forcing in the presence of the insolation forcing but weak evidence for the insolation forcing in the presence of the ice volume for...

  8. Assessing changes in relapse rates in multiple sclerosis.

    Science.gov (United States)

    Inusah, Seidu; Sormani, Maria P; Cofield, Stacey S; Aban, Inmaculada B; Musani, Solomon K; Srinivasasainagendra, Vinodh; Cutter, Gary R

    2010-12-01

    Multiple Sclerosis (MS) annualized relapse rates (ARRs) in trials may be declining due to changes in diagnostic criteria, MS etiology, study criteria, and selection biases. This review examines if there is a trend in the ARR for relapsing-remitting MS patients (RRMS) over time and if so, why. A comprehensive literature search was performed using PubMed, Web of Science(®), and the Cochrane Library using electronic searches, screen scraping for abstracts, and hand searching of references for randomized trials conducted between 1960 and 2008. Out of 72 randomized trials, 56 (77.8%) defined relapse. This study uses 32 placebo relapsing-remitting studies out of the 37 (66.1%) with RRMS. The mean ARR for the treatment arms was 0.68 and the one for the placebo groups was 1.002. The year of publication was negatively associated with the ARR (p = 0.0001). The annual reduction amounts to 0.36 relapses over a 10-year period. Age and duration of symptoms were negatively associated with the ARR. Year of publication was significantly negatively associated with ARR after controlling for covariates. ARRs have fallen with relapse definition, entrance criteria remain important, but time exceeds all these variables and reflects two likely sources, selection of patients for trials by clinicians and rescue of patients truncating the number of multiple relapses. The impact of truncating the number of relapses on the falling rates is important, not only on the ARRs, but also on the impact of informative censoring in drop-outs.

  9. Changes in the width of the tropical belt due to simple radiative forcing changes in the GeoMIP simulations

    Science.gov (United States)

    Davis, Nicholas A.; Seidel, Dian J.; Birner, Thomas; Davis, Sean M.; Tilmes, Simone

    2016-08-01

    this pattern of changes in observations and model experiments, but the results here indicate that seasonally and hemispherically asymmetric tropical expansion can be a basic response of the general circulation to climate forcings.

  10. Rapid changes in corticospinal excitability during force field adaptation of human walking

    DEFF Research Database (Denmark)

    Barthélemy, Dorothy; Alain, S; Grey, Michael James

    2012-01-01

    Force field adaptation of locomotor muscle activity is one way of studying the ability of the motor control networks in the brain and spinal cord to adapt in a flexible way to changes in the environment. Here, we investigate whether the corticospinal tract is involved in this adaptation. We...... be explained by changes in background TA EMG activity. These effects seemed specific to walking, as similar changes in TA MEP were not seen when seated subjects were tested during static dorsiflexion. These observations suggest that the corticospinal tract contributes to the adaptation of walking...

  11. Predicting Offshore Swarm Rate Changes by Volumetric Strain Changes in Izu Peninsula, Japan

    Science.gov (United States)

    Kumazawa, T.; Ogata, Y.; Kimura, Y.; Maeda, K.; Kobayashi, A.

    2014-12-01

    The eastern offshore of Izu peninsula is one of the well known volcanic active regions in Japan, where magma intrusions have been observed several times since 1980s monitored by strain-meters located nearby. Major swarm activities have been synchronously associated with coseismic and preseismic significant sizes of a volumetric strain changes (Earthquake Research Committee, 2010). We investigated the background seismicity changes during these earthquake swarms using the nonstationary ETAS model (Kumazawa and Ogata, 2013), and have found the followings. The modified volumetric strain change data by removing the effect of earth tides and precipitation as well as removing coseismic jumps have much higher cross-correlations to the background rates of the ETAS model than to the whole seismicity rate change of the ETAS, and further the strain changes precede the background seismicity by lag of about a day. This relation suggests an enhanced prediction of earthquakes in this region using volumetric strain measurements. Thus we propose an extended ETAS model where the background seismicity rate is predicted by the time series of preceding volumetric strain changes. Our numerical results for Izu region show consistent outcomes throughout the major swarms in this region. References Earthquake Research Committee (2010). Report on "Prediction of seismic activity in the Izu Eastern Region" (in Japanese), http://www.jishin.go.jp/main/yosoku/izu/index.htm Kumazawa, T. and Ogata, Y. (2013). Quantitative description of induced seismic activity before and after the 2011 Tohoku-Oki earthquake by nonstationary ETAS model, J Geophys.Res. 118, 6165-6182.

  12. 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.

  13. Is climate change an unforeseen, irresistible and external factor - A force majeure in marine environmental law?

    Science.gov (United States)

    Saul, Roxanne; Barnes, Richard; Elliott, Michael

    2016-12-15

    Several environmental laws include provisions on natural causes or force majeure, which except States from their commitments if it can be proven that the failure to meet the commitment is due to factors outside their control. The European Union Marine Strategy Framework Directive (MSFD) has a pivotal role in managing EU marine waters. This paper analyses natural causes and force majeure provisions of the MFSD and other marine legislation, and addresses their interaction with climate change and its consequences, especially the effect on the obligation of ensuring seas are in Good Environmental Status. Climate change is an exogenic unmanaged pressure in that it emanates from outside the area being managed but in which the management authority has to respond to the consequences of climate change, such as sea level rise and temperature elevation, rather than its causes. It is suggested that a defence by a Member State of force majeure may be accepted if an event was proven to be due to an externality of control, irresistible and unforeseeable. The analysis contends that countering such a legal defence would centre on the fact that climate change is a well-accepted phenomenon, is foreseen with an accepted level of confidence and probability and is due to human actions. However, as yet, this has not been legally tested.

  14. On multi-fingerprint detection and attribution of greenhouse gas- and aerosol forced climate change

    Energy Technology Data Exchange (ETDEWEB)

    Hegerl, G.C. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Hasselmann, K. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Cubasch, U. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Mitchell, J.F.B. [Hadley Centre for Climate Prediction and Research, Bracknell (United Kingdom). Meteorological Office; Roeckner, E. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Voss, R. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Waszkewitz, J. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany)

    1996-07-01

    A multi-fingerprint analysis is applied to the detection and attribution of anthropogenic climate change. While a single fingerprint, as applied in a previous paper by Hegerl et al. (1996), is optimal for detecting a significant climate change, the simultaneous use of several fingerprints allows one to investigate additionally the consistency between observations and model predicted climate change signals for competing candidate forcing mechanisms. Thus the multi-fingerprint method is a particularly useful technique for attributing an observed climate change to a proposed cause. Different model-predicted climate change signals are derived from three global warming simulations for the period 1880 to 2049. In one simulation, the forcing was by greenhouse gases only, while in the remaining two simulations the influence of aerosols was also included. The two dominant climate change signals derived from these simulations are optimized statistically by weighting the model-predicted climate change pattern towards low-noise directions. These optimized fingerprints are then applied to observed near surface temperature trends. The space-time structure of natural climate variability (needed to determine the signal-to-noise ratio) is estimated from several multi-century control simulations with different CGCMs and from instrumental data over the last 134 years. (orig.)

  15. Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets

    Energy Technology Data Exchange (ETDEWEB)

    Menon, Surabi; Akbari, Hashem; Mahanama, Sarith; Sednev, Igor; Levinson, Ronnen

    2010-02-12

    The two main forcings that can counteract to some extent the positive forcings from greenhouse gases from pre-industrial times to present-day are the aerosol and related aerosol-cloud forcings, and the radiative response to changes in surface albedo. Here, we quantify the change in radiative forcing and land surface temperature that may be obtained by increasing the albedos of roofs and pavements in urban areas in temperate and tropical regions of the globe by 0.1. Using the catchment land surface model (the land model coupled to the GEOS-5 Atmospheric General Circulation Model), we quantify the change in the total outgoing (outgoing shortwave+longwave) radiation and land surface temperature to a 0.1 increase in urban albedos for all global land areas. The global average increase in the total outgoing radiation was 0.5 Wm{sup -2}, and temperature decreased by {approx}0.008 K for an average 0.003 increase in surface albedo. These averages represent all global land areas where data were available from the land surface model used and are for the boreal summer (June-July-August). For the continental U.S. the total outgoing radiation increased by 2.3 Wm{sup -2}, and land surface temperature decreased by {approx}0.03 K for an average 0.01 increase in surface albedo. Based on these forcings, the expected emitted CO{sub 2} offset for a plausible 0.25 and 0.15 increase in albedos of roofs and pavements, respectively, for all global urban areas, was found to be {approx} 57 Gt CO{sub 2}. A more meaningful evaluation of the impacts of urban albedo increases on global climate and the expected CO{sub 2} offsets would require simulations which better characterizes urban surfaces and represents the full annual cycle.

  16. Spatially Coordinated Changes in Intracellular Rheology and Extracellular Force Exertion during Mesenchymal Stem Cell Differentiation

    Science.gov (United States)

    McAndrews, Kathleen M.; McGrail, Daniel J.; Quach, Nhat D.; Dawson, Michelle R.

    2014-01-01

    The mechanical properties within the cell are regulated by the organization of the actin cytoskeleton, which is linked to the extracellular environment through focal adhesion proteins that transmit force. Chemical and mechanical stimuli alter the organization of cytoskeletal actin, which results in changes in cell shape, adhesion, and differentiation. By combining particle-tracking microrheology and traction force cytometry, we can monitor the mechanical properties of the actin meshwork and determine how changes in the intracellular network contribute to force generation. In this study, we investigated the effects of chemical (differentiation factors) and mechanical (substrate rigidity) stimuli important in mesenchymal stem cell (MSC) differentiation on the intracellular mechanics and traction stress generation. We found the presence of adipogenic factors resulted in stiffening of the actin meshwork regardless of substrate rigidity. In contrast, these factors increased traction stresses on hard substrates, which was associated with increased expression of contractility genes. Furthermore, MSCs cultured on hard substrates expressed both adipogenic and osteogenic markers indicative of mixed differentiation. On hard substrates, heterogeneity in the local elastic modulus-traction stress correlation was also increased in response to adipogenic factors, indicating that these mechanical properties may be reflective of differences in level of MSC differentiation. These results suggest intracellular rheology and traction stress generation are spatially regulated and contribute insight into how single cell mechanical forces contribute to MSC differentiation. PMID:25156989

  17. Spatially coordinated changes in intracellular rheology and extracellular force exertion during mesenchymal stem cell differentiation

    Science.gov (United States)

    McAndrews, Kathleen M.; McGrail, Daniel J.; Quach, Nhat D.; Dawson, Michelle R.

    2014-10-01

    The mechanical properties within the cell are regulated by the organization of the actin cytoskeleton, which is linked to the extracellular environment through focal adhesion proteins that transmit force. Chemical and mechanical stimuli alter the organization of cytoskeletal actin, which results in changes in cell shape, adhesion, and differentiation. By combining particle-tracking microrheology and traction force cytometry, we can monitor the mechanical properties of the actin meshwork and determine how changes in the intracellular network contribute to force generation. In this study, we investigated the effects of chemical (differentiation factors) and mechanical (substrate rigidity) stimuli important in mesenchymal stem cell (MSC) differentiation on the intracellular mechanics and traction stress generation. We found the presence of adipogenic factors resulted in stiffening of the actin meshwork regardless of substrate rigidity. In contrast, these factors increased traction stresses on hard substrates, which was associated with increased expression of contractility genes. Furthermore, MSCs cultured on hard substrates expressed both adipogenic and osteogenic markers indicative of mixed differentiation. On hard substrates, heterogeneity in the local elastic modulus-traction stress correlation was also increased in response to adipogenic factors, indicating that these mechanical properties may be reflective of differences in the level of MSC differentiation. These results suggest intracellular rheology and traction stress generation are spatially regulated and contribute insight into how single cell mechanical forces contribute to MSC differentiation.

  18. The importance of chill rate when characterising colour change of lamb meat during retail display.

    Science.gov (United States)

    Jacob, R H; Thomson, K L

    2012-02-01

    An experiment was conducted to compare the effect of two chilling rates (Con and Fast) on colour change of lamb meat during simulated retail display. Measurements were made on 3 muscles; LD (m. longisimuss dorsi), SM (m semimembranosus) and ST (m. semitendinous). Meat samples from 32 Merino crossbred lambs were vacuum packed and stored for 5 days at 2 °C, then cut and overwrapped in polyvinyl chloride film on black polystyrene trays, stored in a display cabinet at 4 °C with lights on and measured twice daily for 4 days, using a Hunterlab minilab 45/20L D65, aperture 10°. Sarcomere length was shorter, shear force higher and colour change greater in meat from the Fast treatment compared to the Con treatment. Colour differences between treatments were likely due to oxygenation (bloom) as well as oxidation effects. Chill rate is important when characterising colour change during display and should be considered in measurement protocols. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. 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...

  20. Changes in Peak Expiratory Flow Rate, Blood Pressure

    African Journals Online (AJOL)

    FinePrint

    2010-03-23

    Mar 23, 2010 ... (PEFR), blood pressure and pulse rate in an attempt to determine some physiological effects of ... SBP increased significantly at 4g and 6g when compared .... Decrease in heart rate associated with ... exercise performance .

  1. Bilateral deficit in explosive force production is not caused by changes in agonist neural drive.

    Directory of Open Access Journals (Sweden)

    Matthew W Buckthorpe

    Full Text Available Bilateral deficit (BLD describes the phenomenon of a reduction in performance during synchronous bilateral (BL movements when compared to the sum of identical unilateral (UL movements. Despite a large body of research investigating BLD of maximal voluntary force (MVF there exist a paucity of research examining the BLD for explosive strength. Therefore, this study investigated the BLD in voluntary and electrically-evoked explosive isometric contractions of the knee extensors and assessed agonist and antagonist neuromuscular activation and measurement artefacts as potential mechanisms. Thirteen healthy untrained males performed a series of maximum and explosive voluntary contractions bilaterally (BL and unilaterally (UL. UL and BL evoked twitch and octet contractions were also elicited. Two separate load cells were used to measure MVF and explosive force at 50, 100 and 150 ms after force onset. Surface EMG amplitude was measured from three superficial agonists and an antagonist. Rate of force development (RFD and EMG were reported over consecutive 50 ms periods (0-50, 50-100 and 100-150 ms. Performance during UL contractions was compared to combined BL performance to measure BLD. Single limb performance during the BL contractions was assessed and potential measurement artefacts, including synchronisation of force onset from the two limbs, controlled for. MVF showed no BLD (P = 0.551, but there was a BLD for explosive force at 100 ms (11.2%, P = 0.007. There was a BLD in RFD 50-100 ms (14.9%, P = 0.004, but not for the other periods. Interestingly, there was a BLD in evoked force measures (6.3-9.0%, P<0.001. There was no difference in agonist or antagonist EMG for any condition (P≥0.233. Measurement artefacts contributed minimally to the observed BLD. The BLD in volitional explosive force found here could not be explained by measurement issues, or agonist and antagonist neuromuscular activation. The BLD in voluntary and evoked explosive force

  2. RAPID PENUMBRA AND LORENTZ FORCE CHANGES IN AN X1.0 SOLAR FLARE

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhe; Jiang, Yunchun; Yang, Jiayang; Yang, Bo; Bi, Yi, E-mail: xuzhe6249@ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)

    2016-03-20

    We present observations of the violent changes in photospheric magnetic structures associated with an X1.1 flare, which occurred in a compact δ-configuration region in the following part of AR 11890 on 2013 November 8. In both central and peripheral penumbra regions of the small δ sunspot, these changes took place abruptly and permanently in the reverse direction during the flare: the inner/outer penumbra darkened/disappeared, where the magnetic fields became more horizontal/vertical. Particularly, the Lorentz force (LF) changes in the central/peripheral region had a downward/upward and inward direction, meaning that the local pressure from the upper atmosphere was enhanced/released. It indicates that the LF changes might be responsible for the penumbra changes. These observations can be well explained as the photospheric response to the coronal field reconstruction within the framework of the magnetic implosion theory and the back reaction model of flares.

  3. Predicting demographically sustainable rates of adaptation : Can great tit breeding time keep pace with climate change?

    NARCIS (Netherlands)

    Gienapp, Phillip; Lof, Marjolein; Reed, Thomas E.; McNamara, John; Verhulst, Simon; Visser, Marcel E.

    2013-01-01

    Populations need to adapt to sustained climate change, which requires micro-evolutionary change in the long term. A key question is how the rate of this micro-evolutionary change compares with the rate of environmental change, given that theoretically there is a 'critical rate of environmental

  4. A study on the changes in attractive force of magnetic attachments for overdenture

    Science.gov (United States)

    Lee, Jong-Hyuk; Choi, Yu-Sung

    2016-01-01

    PURPOSE Although magnetic attachment is used frequently for overdenture, it is reported that attractive force can be decreased by abrasion and corrosion. The purpose of this study was to establish the clinical basis about considerations and long term prognosis of overdenture using magnetic attachments by investigating the change in attractive force of magnetic attachment applied to the patients. MATERIALS AND METHODS Among the patients treated with overdenture using magnetic attachments in Dankook University Dental Hospital, attractive force records of 61 magnetic attachments of 20 subjects who re-visited from July 2013 to June 2014 were analyzed. Dental magnet tester (Aichi Micro Intelligent Co., Aichi, Japan) was used for measurement. The magnetic attachments used in this study were Magfit IP-B Flat, Magfit DX400, Magfit DX600 and Magfit DX800 (Aichi Steel Co., Aichi, Japan) filled with Neodymium (NdFeB), a rare-earth magnet. RESULTS Reduction ratio of attractive force had no significant correlation with conditional variables to which attachments were applied, and was higher when the maintenance period was longer (P<.05, r=.361). Reduction ratio of attractive force was significantly higher in the subject group in which attachments were used over 9 years than within 9 years (P<.05). Furthermore, 16.39% of total magnetic attachments showed detachment of keeper or assembly. CONCLUSION Attractive force of magnetic attachment is maintained regardless of conditional variables and reduction ratio increased as the maintenance period became longer. Further study on adhesive material, attachment method and design improvement to prevent detachment of magnetic attachment is needed. PMID:26949482

  5. 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,…

  6. Hybrid Methods and Atomistic Models to Explore Free Energies, Rates and Pathways of Protein Shape Changes

    DEFF Research Database (Denmark)

    Wang, Yong

    biologist, I was proud and excited for the breaking news as this prize is not only to them, but also to the whole community of computational biology. There has been progress in the modeling of protein dynamics in recent years and it has also started to be clear that computer simulations play...... folding, conformational exchange and binding with ligands at long time scales. In Chapter 2, we benchmarked how well the current force elds and molecular dynamics (MD) simulations could model changes in structure, dynamics, free energy and kinetics for an extensively studied protein called T4 lysozyme (T4...... allows us to utilize the limited computational resources in a more reasonable way. In Chapter 5, we further illustrated the possibility to combine the free energy ooding potential obtained from the variational method with infrequent metadynamics to calculate the long timescale rate. This hybrid method...

  7. Secular changes in body dimensions of Royal Australian Air Force aircrew (1971-2005).

    Science.gov (United States)

    Tomkinson, Grant R; Clark, Adam J; Blanchonette, Peter

    2010-08-01

    The aim of this study was to quantify the secular changes in body dimensions of Royal Australian Air Force aircrew. Following corrections for methodological differences, two samples (matched for age and overall body size) of male aircrew measured in 1971 (n = 220) and 2005 (n = 220) were compared across 13 absolute and proportional body dimensions. Changes in means were expressed as standardised effect sizes and changes in distributional characteristics were expressed as the ratio of coefficients of variation and as changes in skew. Small secular increases (standardised effects sizes >0.2) in age-matched aircrew were observed for mass, height, BMI, sitting height, buttock-knee length, waist girth, hip girth and waist:hip ratio, with a small decline observed for head girth. Changes in body dimensions were not independent of changes in overall body size (except for head girth) and were not always uniform across the distribution. These changes in body size have implications for ensuring correct human-machine and human-equipment fit. STATEMENT OF RELEVANCE: There have been small secular changes in body dimensions of RAAF aircrew between 1971 and 2005, although these secular changes have not always been uniform across the distribution. These secular changes in body dimensions have implications for ensuring correct human-machine and human-equipment fit and underscore the need for regular anthropometric surveys.

  8. Analysis on Temporal and Spatial Changes and Driving Forces of Poverty-Stricken Areas in Hebei Province

    Institute of Scientific and Technical Information of China (English)

    Shi Xiaoli; Yuan Jinguo; Wang Wei

    2005-01-01

    This paper takes poverty-stricken county as the basic unit, and selects net income per peasant to study the poverty status in Hebei Province during 1986~2000.Temporal and spatial changes of povertystricken areas are analyzed. The result shows that poverty-stricken areas in Hebei Province distributed concentratedly and the areas decreased during 1986~2000, the net income per peasant was on the rise with an increasing speed in off-poverty counties being slightly higher than that in poverty-stricken counties, but the growth rate was extremely unstable,rising slowly in off-poverty counties while dropping in poverty-stricken counties. The main driving forces that influenced temporal and spatial changes were economic development of the whole province,ecological environment quality, infrastructure conditions and radiation of the key city. On this basis, some anti-poverty countermeasures suitable to local conditions are proposed.

  9. Pathway to Change? An Appraisal of the Australian Defence Force’s Strategy for Cultural Change

    Science.gov (United States)

    2013-12-13

    ILLUSTRATIONS Page Figure 1. A Multisystem Ethical Framework ..................................................................26 Figure 2. The...respectively, Linda Trevino and Katherine Nelson’s 6 “Multisystem Ethical Culture Framework ,” and Peter Checkland’s “Soft System Methodology.” Chapter...academics in the field of organizational change, including Geert Hofstede and Edgar Schein: “A set of shared mental assumptions that guide interpretation

  10. Spatial heterogeneity of the driving forces of cropland change in China

    Institute of Scientific and Technical Information of China (English)

    LIU; Xuhua; WANG; Jinfeng; LIU; Mingliang; MENG; Bin

    2005-01-01

    By using digital satellite remote sensing data acquired in 1987―1989 and 1999―2000 and GIS combined with the natural and socio-economic data, this paper drew an integrated zonation of the cropland change and its driving forces in China. The results indicated that the cropland change in the study period was constrained by geographical factors and driven by climate change as well as socio-economic system. Moreover, the regional differences of the drivers for cropland change were significant. In the midwest of China, natural condition changes and geographical background were the main constraints and drivers, while in Eastern China, social and economic changes and economic policies were the main driving forces. The cropland loss was nationwide. The dominant factors to cause this decrease included buildup of developing area to attract foreign capital and technologies, changes of industry structure due to urban influence, the change of employment notions thanks to living standard improvement, rapid urbanization due to the expansion of cities and towns, the diminished farming net income partly because of the global warming effects, and the rapid economic growth stimulated by the convenient transportation system. These factors interact and interdepend with each other to cause the cropland loss in China recently. The reasons for the increase of cropland were primarily the cultivation and deforestation by the farmers who want to increase income. This study on the mechnism of LUCC relied on the cropland change integrated classification considering the natural or human factors both inside and outside the region, which provides a new approach to study the integrated regionalization and LUCC mechanism.

  11. 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.

  12. Toward a transtheoretical model of interprofessional education: stages, processes and forces supporting institutional change.

    Science.gov (United States)

    Clark, Phillip G

    2013-01-01

    The history of interprofessional education (IPE) in the USA is a checkered one, characterized by boom and bust cycles of advancement and retrenchment, expansion and contraction. The successful development, implementation and continuation of IPE in health and social care in US higher education institutions all depend on a number of factors related to how individuals and organizations do or do not support it in the academic setting. Deliberate and planned change to advance IPE requires a comprehensive theoretical framework to guide it and insure its success. A transtheoretical model (TTM) of institutional change is proposed as a comprehensive framework of the stages, processes and forces that can facilitate and maintain change in support of IPE. The TTM framework recognizes the complexity of change, and captures and organizes important elements from different organizational theories. It also provides a structure for conceptualizing the multiple dimensions needed for change, offering intervention strategies and leverage points to be used by leaders in promoting and maintaining it. Finally, the TTM model suggests that the stabilization of IPE programs over the long term is dependent on a real and significant shift in institutional values in response to forces from both within and without the organization.

  13. On arable land changes in Shandong Province and their driving forces

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The decrease of total cultivated area and the lower per capitaavailable arable land resource are now serious problems in Shandong Province, a major agricultural province in China. These problems will become more serious along with the further development of economy. In this paper,based on the statistical information at provincial and county levels, the changes of arable land in Shandong Province and their driving forces during the last 50 years are analyzed. The general changing trends of arable land and per capita available arable land are reducing, and the trends of decrease will continue when the economy is developing. The result of GIS spatial analysis shows that the change of the arable land use in Shandong Province has a regional difference. Eight variables having influences on cultivated land change are analyzed by principal component analysis. The results show that the dynamic development of economy, pressure of social system and progress of scientific techniques in agriculture are the main causes for cultivated land reduction. The principal factors which can be considered as driving forces for arable land change include per capita net living space, total population and per ha grain yield. By using regressive equation, along with analysis on population growth and economic development, cultivated areas in Shandong Province in 2005 and 2010 are predicted respectively. The predicted cultivated areas in Shandong will be 6435.47 thousand hain 2005 and 6336.23 thousand ha in 2010 respectively.

  14. Real-time changes in corticospinal excitability related to motor imagery of a force control task.

    Science.gov (United States)

    Tatemoto, Tsuyoshi; Tsuchiya, Junko; Numata, Atsuki; Osawa, Ryuji; Yamaguchi, Tomofumi; Tanabe, Shigeo; Kondo, Kunitsugu; Otaka, Yohei; Sugawara, Kenichi

    2017-09-29

    To investigate real-time excitability changes in corticospinal pathways related to motor imagery in a changing force control task, using transcranial magnetic stimulation (TMS). Ten healthy volunteers learnt to control the contractile force of isometric right wrist dorsiflexion in order to track an on-screen sine wave form. Participants performed the trained task 40 times with actual muscle contraction in order to construct the motor image. They were then instructed to execute the task without actual muscle contraction, but by imagining contraction of the right wrist in dorsiflexion. Motor evoked potentials (MEPs), induced by TMS in the right extensor carpi radialis muscle (ECR) and flexor carpi radialis muscle (FCR), were measured during motor imagery. MEPs were induced at five time points: prior to imagery, during the gradual generation of the imaged wrist dorsiflexion (Increasing phase), the peak value of the sine wave, during the gradual reduction (Decreasing phase), and after completion of the task. The MEP ratio, as the ratio of imaged MEPs to resting-state, was compared between pre- and post-training at each time point. In the ECR muscle, the MEP ratio significantly increased during the Increasing phase and at the peak force of dorsiflexion imagery after training. Moreover, the MEP ratio was significantly greater in the Increasing phase than in the Decreasing phase. In the FCR, there were no significant consistent changes. Corticospinal excitability during motor imagery in an isometric contraction task was modulated in relation to the phase of force control after image construction. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. CHANGE@CERN:Task Force 3: adjusting services to future needs

    CERN Multimedia

    2002-01-01

    We continue our articles on the Task Force reports The number of craftsmen and technicians could be increased with a change in the staff composition. The mandate for Task Force 3 was to make proposals for savings and new cost control procedures in the area of Industrial Support and Contracts for the period until 2009. The aim, explains the convenor, Karl-Heinz Kissler, was to keep spending under control under difficult conditions when staff numbers are decreasing and the work for the LHC becomes more demanding. The measures proposed, if implemented, could lead to savings of around 170 MCHF. The proposals involve both Industrial Services contracts, which were discussed in the Bulletin of the 22nd of April (n°17/2002) and readjustments for staff at CERN, on which we concentrate here. As with other Task Forces the principle aim was to be able to refocus resources onto the LHC project. In this respect, Task Force 3 could work within the framework of the revised programme for the LHC and the reduced non-LHC pro...

  16. 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.

  17. Assessing the relative rate of (mitochondrial) genomic change.

    OpenAIRE

    Dowton, Mark

    2004-01-01

    I report a framework for assessing whether one mitochondrial genome is significantly more rearranged than another. This relative rate of gene rearrangement test (RGR) behaves according to expectation, distinguishing between highly rearranged and mildly rearranged insect mitochondrial genomes. It may be more broadly applied to assess the relative rate of nuclear gene rearrangement.

  18. Assessing the relative rate of (mitochondrial) genomic change.

    Science.gov (United States)

    Dowton, Mark

    2004-06-01

    I report a framework for assessing whether one mitochondrial genome is significantly more rearranged than another. This relative rate of gene rearrangement test (RGR) behaves according to expectation, distinguishing between highly rearranged and mildly rearranged insect mitochondrial genomes. It may be more broadly applied to assess the relative rate of nuclear gene rearrangement.

  19. 78 FR 283 - 2013 Rate Changes for the Basetime, Overtime, Holiday, and Laboratory Services Rates

    Science.gov (United States)

    2013-01-03

    ... cost of living increase, plus the benefits rate, plus the travel and operating rate, plus the overhead... calendar year's percentage of cost of living increase, multiplied by 1.5, plus the benefits rate, plus the... year's regular hours, plus that quotient multiplied by the calendar year's percentage of cost of living...

  20. Increased rate of acceleration on Pine Island Glacier strongly coupled to changes in gravitational driving stress

    Directory of Open Access Journals (Sweden)

    J. B. T. Scott

    2009-05-01

    Full Text Available Pine Island Glacier, Antarctica, has been undergoing several related changes for at least two decades; these include acceleration, thinning and grounding line retreat. During the first major ground-based study between 2006 and 2008, GPS receivers were used to monitor ice flow from 55 km to 171 km inland, along the central flowline. At four sites both acceleration and thinning rates over the last two years exceeded rates observed at any other time over the last two decades. At the downstream site acceleration was 6.4% over 2007 and thinning was 3.5±0.5 ma−1. Acceleration and thinning have spread rapidly inland with the acceleration 171 km inland at 4.1% over 2007, greater than any measured annual flow increase along the whole glacier prior to 2006. Increases in surface slope, and hence gravitational driving stress, correlate well with the acceleration and no sustained change in longitudinal stress gradient is needed to explain the force balance. There is no indication that the glacier is approaching a new steady state.

  1. Changes in temporal variability of precipitation over land due to anthropogenic forcings

    Science.gov (United States)

    Konapala, Goutam; Mishra, Ashok; Leung, L. Ruby

    2017-02-01

    This study investigated the anthropogenic influence on the temporal variability of annual precipitation for the period 1950–2005 as simulated by the CMIP5 models. The temporal variability of both annual precipitation amount (PRCPTOT) and intensity (SDII) was first measured using a metric of statistical dispersion called the Gini coefficient. Comparing simulations driven by both anthropogenic and natural forcing (ALL) with simulations of natural forcing only (NAT), we quantified the anthropogenic contributions to the changes in temporal variability at global, continental and sub-continental scales as a relative difference of the respective Gini coefficients of ALL and NAT. Over the period of 1950–2005, our results indicate that anthropogenic forcing have resulted in decreased uniformity (i.e. increase in unevenness or disparity) in annual precipitation amount and intensity at global as well as continental scales. In addition, out of the 21 sub-continental regions considered, 14 (PRCPTOT) and 17 (SDII) regions showed significant anthropogenic influences. The human impacts are generally larger for SDII compared to PRCTOT, indicating that the temporal variability of precipitation intensity is generally more susceptible to anthropogenic influence than precipitation amount. The results highlight that anthropogenic activities have changed not only the trends but also the temporal variability of annual precipitation, which underscores the need to develop effective adaptation management practices to address the increased disparity.

  2. Changes in temporal variability of precipitation over land due to anthropogenic forcings

    Energy Technology Data Exchange (ETDEWEB)

    Konapala, Goutam; Mishra, Ashok; Leung, L. Ruby

    2017-02-01

    This study investigated the anthropogenic influence on the temporal variability of annual precipitation for the period 1950-2005 as simulated by the CMIP5 models. The temporal variability of both annual precipitation amount (PRCPTOT) and intensity (SDII) was first measured using a metric of statistical dispersion called the Gini coefficient. Comparing simulations driven by both anthropogenic and natural forcings (ALL) with simulations of natural forcings only (NAT), we quantified the anthropogenic contributions to the changes in temporal variability at global, continental and sub-continental scales as a relative difference of the respective Gini coefficients of ALL and NAT. Over the period of 1950-2005, our results indicate that anthropogenic forcings have resulted in decreased uniformity (i.e., increase in unevenness or disparity) in annual precipitation amount and intensity at global as well as continental scales. In addition, out of the 21 sub-continental regions considered, 14 (PRCPTOT) and 17 (SDII) regions showed significant anthropogenic influences. The human impacts are generally larger for SDII compared to PRCTOT, indicating that the temporal variability of precipitation intensity is generally more susceptible to anthropogenic influence than precipitation amount. The results highlight that anthropogenic activities have changed not only the trends but also the temporal variability of annual precipitation, which underscores the need to develop effective adaptation management practices to address the increased disparity.

  3. [Typical spontaneous changes in heart rate in pheochromocytoma].

    Science.gov (United States)

    Bramann, H U; Zidek, W; Vetter, H; Grosse-Heitmeyer, W

    1985-01-01

    Investigations in 13 hospitalized patients with pheochromocytomata showed peculiar characteristics of heart rate variation at rest, when compared with normals. All patients were given alpha- and beta-sympatholytic drugs. In one case alpha-methyl-Tyrosine caused I-II degree AV blocks and a stable high frequency sinus rate without physiological variations. Resting heart rate in pheochromocytoma varied interindividually from 55-105/min, in the absence of clinical attacks of the underlying disease. The frequency profile was characterized in 12 patients by sudden and inadequate rises of heart rate (200%) of short duration, which were often recorded within 20 seconds of the onset of muscular activity. A similar but less pronounced heart rate modulation was found 1-2 weeks after operation in 3 cases. Our observations indicate that the heart rate profile described may be a sensitive parameter of dysfunction of the autonomous nervous system in pheochromocytoma. Whether the heart rate characteristics are of diagnostic value has to be assessed by further studies.

  4. Credit Rating Change and Capital Structure in Latin America

    Directory of Open Access Journals (Sweden)

    Dany Rogers

    2016-04-01

    Full Text Available This study analyzes the impact of imminent reclassification of credit rating on the decision-making regarding capital structure of non-financial corporations listed in Latin America. Despite the importance attributed by the market agents and the existence of empirical evidence of the effect caused by rating in the capital structure of companies in developed countries, this issue is still incipient in Latin-American countries. For this purpose, all the non-financial corporation owners of, at least one corporate rating issued by an international rating agency were taken into account, with the requirement of being listed on a stock exchange in at least one Latin-American country. Through a data panel analysis comprising the period between 2001 and 2010 and by making use of the Generalized Method of Moments (GMM, the main results that were achieved did not indicate that non-financial corporations listed in Latin America, with imminent reclassification of ratings, adopt less debts than those without an imminent reclassification of their ratings. These findings suggest that the imminent reclassifications of credit ratings do not present important information for managers of non-financial corporations in Latin America when making decisions about capital structure.

  5. Aging and physiological changes of the kidneys including changes in glomerular filtration rate.

    Science.gov (United States)

    Musso, Carlos G; Oreopoulos, Dimitrios G

    2011-01-01

    In addition to the structural changes in the kidney associated with aging, physiological changes in renal function are also found in older adults, such as decreased glomerular filtration rate, vascular dysautonomia, altered tubular handling of creatinine, reduction in sodium reabsorption and potassium secretion, and diminished renal reserve. These alterations make aged individuals susceptible to the development of clinical conditions in response to usual stimuli that would otherwise be compensated for in younger individuals, including acute kidney injury, volume depletion and overload, disorders of serum sodium and potassium concentration, and toxic reactions to water-soluble drugs excreted by the kidneys. Additionally, the preservation with aging of a normal urinalysis, normal serum urea and creatinine values, erythropoietin synthesis, and normal phosphorus, calcium and magnesium tubular handling distinguishes decreased GFR due to normal aging from that due to chronic kidney disease.

  6. 图算角变力矩法%Chart Calculation Angular Change Force Moment Method

    Institute of Scientific and Technical Information of China (English)

    马楠

    2012-01-01

    The method of moment distribution is one kind of the mechanics analytical method with wide-ranging application in the engineering field. Angular change force moment is defined as the amount of the angular displacement of the structure joints expressed by force moment. Chart calculation angular change force moment method is defined as the method of solving the hyperstatic structure with the help of the concepts of the method of moment distribution. Its unknown amount is the angular change force moment and its object is the calculation chart. This is also the calculation while looking at the calculation chart. Chart calculation angular change force moment method is against the demerits such as the many waiting-for calculation amounts and the progressive calculation and the approximation with the error of truncation and so on in the method of moment distribution. Of course,it also externalized the merits such as the normalizing-calculation modality and the clear thought way and the reduced mind labour conveniently. Thus it has been one kind of the direct and accurate mechanics analytic method that has been the foundation of hyperstatic structure in order to build a common and unified mechanics analytic method.%力矩分配法,是工程界常用的手算结构的力学分析方法.以力矩表达结构结点角位移的量,称为角变力矩.以角变力矩为未知量,以计算图为对象利用力矩分配法概念求解超静定结构的方法,称为图算角变力矩法,即边看图边计算角变力矩的方法.图算角变力矩法,克服了力矩分配法直接待求量个数多、计算的渐近性和有截断误差的近似性等缺点,发扬了力矩分配法计算程式规范,省脑力、思路清晰等优点,成为一种直接精确的力学分析方法,为建立超静定结构普遍统一的力学分析方法奠定了基础.

  7. The Sensitivity of Regional Precipitation to Global Temperature Change and Forcings

    Science.gov (United States)

    Tebaldi, C.; O'Neill, B. C.; Lamarque, J. F.

    2016-12-01

    Global policies are most commonly formulated in terms of climate targets, like the much talked about 1.5° and 2°C warming thresholds identified as critical by the recent Paris agreements. But what does a target defined in terms of a globally averaged quantity mean in terms of expected regional changes? And, in particular, what should we expect in terms of significant changes in precipitation over specific regional domains for these and other incrementally different global goals? In this talk I will summarize the result of an analysis that aimed at characterizing the sensitivity of regional temperatures and precipitation amounts to changes in global average temperature. The analysis uses results from a multi-model ensemble (CMIP5), which allows us to address structural uncertainty in future projections, a type of uncertainty particularly relevant when considering precipitation changes. I will show what type of changes in global temperature and forcing levels bring about significant and pervasive changes in regional precipitation, contrasting its sensitivity to that of regional temperature changes. Because of the large internal variability of regional precipitation, I will show that significant changes in average regional precipitation can be detected only for fairly large separations (on the order of 2.5° or 3°C) in global average temperature levels, differently from the much higher sensitivity shown by regional temperatures.

  8. How Does the PAC Respond to Changes in the Payment Rate

    Data.gov (United States)

    U.S. Department of Health & Human Services — How Does the Volume of Post-Acute Care Respond to Changes in the Payment Rate Measure the effect of changes from 1997 to 2001 in Medicares payment rates for skilled...

  9. Drag Forces, Neutral Wind and Electric Conductivity Changes in the Ionospheric E Region

    CERN Document Server

    Nenovski, Petko

    2014-01-01

    The neutrals in the Earth environment are in fact free and subjected to drag forces (by ions). In this study we show that drag or friction forces in the ionosphere-thermosphere system initiate changes in the plasma flow, neutral wind, and the conductivity, as well. Ions and electrons embedded in neutral wind field of velocity u acquire drifts perpendicular both to the initial neutral wind velocity and to the ambient magnetic field producing a perpendicular electric current. This perpendicular electric current is defined by a conductivity derived previously and the polarization electric field u x B. Self-consistently, the free neutrals acquires an additional neutral velocity component perpendicular to the initial neutral wind velocity u. The Pedersen and Hall currents wane within a specific time inversely proportional to neutral-ion collision frequency. These findings are relevant to a better understanding of electric current generation, distribution and closure in weakly ionized plasmas where charged particle...

  10. 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

  11. 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.

  12. Contributions of Asian pollution and SST forcings on precipitation change in the North Pacific

    Science.gov (United States)

    Yeh, Sang-Wook; So, Jihyeon; Lee, Jong-Won; Kim, Minjoong J.; Jeong, Jaein I.; Park, Rokjin J.

    2017-08-01

    East Asia has a significant concentration of pollutant aerosols, mostly due to rapid industrialization. Previous research indicates that the aerosol effect from Asian pollution outflow could account for the trend of increasing deep convective clouds, as well as an intensification of the storm track, over the North Pacific Ocean in winter since the mid-1990s. However, it is not clear whether such change is solely due to Asian pollutant forcings or not. To understand the relative roles of Asian pollutant aerosols and sea surface temperature (SST) forcings on the precipitation change in the North Pacific, we examine the interannual variation of particulate matter 2.5 (PM2.5) simulated in the global chemical transport model (GEOS-Chem) and the idealized experiments using the Community Atmosphere Model version 5 (CAM5) for 1986-2010. The composite analysis indicates that the changes in precipitation amount and storm track intensity in the southwestern North Pacific might be associated with the increase in PM2.5 concentration in East China. However, El Niño-like warming during the years of high PM2.5 concentration may also influence the precipitation amount, as well as the storm track intensity in the central and eastern North Pacific. Model experiments also indicate that the El Niño-like warming and the Asian pollutant aerosols have different effects on precipitation amounts in the North Pacific. Therefore, the precipitation changes, as well as the intensification of the storm track, in the North Pacific might be attributed to both Asian pollutant aerosols and SST forcing in the tropics.

  13. 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.

  14. Reproductive value, the stable stage distribution, and the sensitivity of the population growth rate to changes in vital rates

    Directory of Open Access Journals (Sweden)

    Hal Caswell

    2010-09-01

    Full Text Available The population growth rate, or intrinsic rate of increase, measures the potential rate of growth of a population with specified and fixed vital rates.The sensitivity of population growth rate to changes in the vital rates can be written in terms of the stable stage or age distribution and the reproductive value distribution. If the vital rate measures the rate of production of one type of individual by another, then the sensitivity of growth rate is proportional to the reproductive value of the destination type and the representation in the stable stage distribution of the source type. This formal relationship exists in three forms: one limited to age-classified populations, a second that applies to stage- or age-classified populations, and a third that uses matrix calculus. Each uses a different set of formal demographic techniques; together they provide a relationship that beautifully cuts across different types of demographic models.

  15. 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.

  16. Rate-of-change limiter for quantized signals

    Science.gov (United States)

    Streuding, G. C.

    1977-01-01

    Analog circuit is employed to smooth change between levels of quantized voltage signal without adversely affecting its fidelity. Circuit is applicable to units requiring interface between digital and analog systems such as automated manufacturing systems or industrial robots.

  17. Adaptation to climate change: changes in farmland use and stocking rate in the U.S.

    Science.gov (United States)

    Mu, Jianhong E.; McCarl, Bruce A.; Wein, Anne M.

    2013-01-01

    This paper examines possible adaptations to climate change in terms of pasture and crop land use and stocking rate in the United States (U.S.). Using Agricultural Census and climate data in a statistical model, we find that as temperature and precipitation increases agricultural commodity producers respond by reducing crop land and increasing pasture land. In addition, cattle stocking rate decreases as the summer Temperature-humidity Index (THI) increases and summer precipitation decreases. Using the statistical model with climate data from four General Circulation Models (GCMs), we project that land use shifts from cropping to grazing and the stocking rate declines, and these adaptations are more pronounced in the central and the southeast regions of the U.S. Controlling for other farm production variables, crop land decreases by 6 % and pasture land increases by 33 % from the baseline. Correspondingly, the associated economic impact due to adaptation is around -14 and 29 million dollars to crop producers and pasture producers by the end of this century, respectively. The national and regional results have implications for farm programs and subsidy policies.

  18. Analysis of Corporate Income Tax Rate Changes and Earnings Management

    OpenAIRE

    Mulyadi, Martin Surya; Anwar, Yunita; Yanny, Lili

    2013-01-01

    Özet: It is known that tax is one of the biggest contributor to state income all over the world. For Indonesia, income tax contribute an average of 36% to the state’s income. With the high contribution of tax, government could adjust the income tax rate in order to increase the tax income. However, the high rate of income tax would have an impact to investment decision as tax will reduce the net income. Usually the taxpayer will apply an earnings management in order to avoid high tax payme...

  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. A MODEL OF THE FORCES THAT GENERATE RESISTANCE TO CHANGE WITHIN AN ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Daniela BRADUŢANU

    2015-12-01

    Full Text Available The aim of this article is to present a proposed model of the forces generating resistance to change within an organiza-tion. After analyzing the literature and conducting a survey I concluded that the forces that generate resistance to change have a great impact on employees’ resistance to change and they are both internal, as well as external.UN MODEL AL FORŢELOR GENERATOARE DE REZISTENŢĂ LA SCHIMBARE DIN CADRUL UNEI ORGANIZAŢIIScopul urmărit în acest articol este de a prezenta un model al forţelor generatoare de rezistenţă la schimbare din cadrul unei organizaţii. În urma analizei literaturii de specialitate şi efectuării unui studiu de caz am ajuns la concluzia că forţele care generează rezistenţă la schimbare au un impact semnificativ asupra rezistenţei la schimbare din partea angajaţilor, acestea fiind atât interne, cât şi externe.

  1. Fetal heart rate changes associated with general anesthesia.

    Science.gov (United States)

    Fedorkow, D M; Stewart, T J; Parboosingh, J

    1989-07-01

    Decreased fetal heart rate variability was noted 90 seconds after the induction of general anesthesia with sodium thiopentone and fentanyl in a patient undergoing basket extraction of a renal calculus at 30 weeks' gestation. The fetal sleep pattern lasted for 105 minutes after the anesthetic was discontinued, 45 minutes after the mother was fully awake.

  2. 18 CFR 157.217 - Changes in rate schedules.

    Science.gov (United States)

    2010-04-01

    ... CONVENIENCE AND NECESSITY AND FOR ORDERS PERMITTING AND APPROVING ABANDONMENT UNDER SECTION 7 OF THE NATURAL... authorization. The certificate holder is authorized to permit an existing customer, at the customer's request... limitations on deliveries to the customer under both rate schedules are not increased, for either annual...

  3. Atomic Force Microscopy Studies on DNA Structural Changes Induced by Vincristine Sulfate and Aspirin

    Science.gov (United States)

    Zhu, Yi; Zeng, Hu; Xie, Jianming; Ba, Long; Gao, Xiang; Lu, Zuhong

    2004-04-01

    We report that atomic force microscopy (AFM) studies on structural variations of a linear plasmid DNA interact with various concentrations of vincristine sulfate and aspirin. The different binding images show that vincrinstine sulfate binding DNA chains caused some loops and cleavages of the DNA fragments, whereas aspirin interaction caused the width changes and conformational transition of the DNA fragments. Two different DNA structural alternations could be explained by the different mechanisms of the interactions with these two components. Our work indicates that the AFM is a powerful tool in studying the interaction between DNA and small molecules.

  4. Atomic force microscopy studies on circular DNA structural changes by vincristine and aspirin.

    Science.gov (United States)

    Xiao, Zhongdang; Cao, Lili; Zhu, Dan; Lu, Zuhong

    2011-01-01

    In this chapter, we have presented materials and methods to study the interaction between DNA and small molecule drugs by AFM. The detailed AFM imaging of the circular DNA after incubation with -various concentrations of vincristine and aspirin have been demonstrated. The immobilization of DNA fragments on mica surface as well as the force between tip and sample plays an important role for successful imaging of DNA-drug complexes. How to quantitatively describe the conformations and structures of circular DNA molecules and their changes is also introduced. Our work indicates that the AFM is a powerful tool in studying the interaction between DNA and small molecules.

  5. Force-EMG changes during sustained contractions of a human upper airway muscle.

    Science.gov (United States)

    Schmitt, Kori; DelloRusso, Christiana; Fregosi, Ralph F

    2009-02-01

    Human upper airway and facial muscles support breathing, swallowing, speech, mastication, and facial expression, but their endurance performance in sustained contractions is poorly understood. The muscular fatigue typically associated with task failure during sustained contractions has both central and intramuscular causes, with the contribution of each believed to be task dependent. Previously we failed to show central fatigue in the nasal dilator muscles of subjects that performed intermittent maximal voluntary contractions (MVCs). Here we test the hypothesis that central mechanisms contribute to the fatigue of submaximal, sustained contractions in nasal dilator muscles. Nasal dilator muscle force and EMG activities were recorded in 11 subjects that performed submaximal contractions (20, 35, and 65% MVC) until force dropped to or=3 s, which we defined as task failure. MVC and twitch forces (the latter obtained by applying supramaximal shocks to the facial nerve) were recorded before the trial and at several time points over the first 10 min of recovery. The time to task failure was inversely related to contraction intensity. MVC force was depressed by roughly 30% at task failure in all three trials, but recovered within 2 min. Twitch force fell by 30-44% depending on contraction intensity and remained depressed after 10 min of recovery, consistent with low-frequency fatigue. Average EMG activity increased with time, but never exceeded 75% of the maximal, pretrial level despite task failure. EMG mean power frequency declined by 20-25% in all trials, suggesting reduced action potential conduction velocity at task failure. In contrast, the maximal evoked potential did not change significantly in any of the tasks, indicating that the EMG deficit at task failure was due largely to mechanisms proximal to the neuromuscular junction. Additional experiments using the interpolated twitch technique suggest that subjects can produce about 92% of the maximal evocable force

  6. 75 FR 69143 - Postal Rate and Classification Changes

    Science.gov (United States)

    2010-11-10

    ... Geographic Markets. Subject to Postal Service approval, customers designate specific geographic target... year. Up to 20 SCFs may be selected or up to five target markets (consisting of multiple contiguous... three price adjustments and related classification changes for market dominant products.\\1\\ The...

  7. Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise

    Science.gov (United States)

    Baum, K.; Essfeld, D.; Stegemann, J.

    To investigate the effect of μg-induced peripheral extracellular fluid reductions on heart rate and blood pressure during isometric exercise, six healthy male subjects performed three calf ergometer test with different extracellular volumes of working muscles. In all tests, body positions during exercise were identical (supine with the knee joint flexed to 900). After a pre-exercise period of 25 min, during which calf volumes were manipulated, subjects had to counteract an external force of 180 N for 5 min. During the pre-exercise period three different protocols were applied. Test A: Subjects rested in the exercise position; test B: Body position was the same as in A but calf volume was increased by venous congestion (cuffs inflated to 80 mm Hg); test C: Calf volumes were decreased by a negative hydrostatic pressure (calves about 40 cm above heart level with the subjects supine). To clamp the changed calf volumes in tests B and C, cuffs were inflated to 300 mm Hg 5 min before the onset of exercise. This occlusion was maintained until termination of exercise. Compared to tests A and B, the reduced volume of test C led to significant increases in heart rate and blood pressure during exercise. Oxygen uptake did not exceed resting levels in B and C until cuffs were deflated, indicating that exclusively calf muscles contributed to the neurogenic peripheral drive. It is concluded that changes in extracellular muscle volume have to be taken into account when comparing heart rate and blood pressure during lg- and μg- exercise.

  8. 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.

  9. Endothelial Cell Senescence Increases Traction Forces due to Age-Associated Changes in the Glycocalyx and SIRT1.

    Science.gov (United States)

    Cheung, Tracy M; Yan, Jessica B; Fu, Justin J; Huang, Jianyong; Yuan, Fan; Truskey, George A

    2015-03-01

    Endothelial cell (EC) aging and senescence are key events in atherogenesis and cardiovascular disease development. Age-associated changes in the local mechanical environment of blood vessels have also been linked to atherosclerosis. However, the extent to which cell senescence affects mechanical forces generated by the cell is unclear. In this study, we sought to determine whether EC senescence increases traction forces through age-associated changes in the glycocalyx and antioxidant regulator deacetylase Sirtuin1 (SIRT1), which is downregulated during aging. Traction forces were higher in cells that had undergone more population doublings and changes in traction force were associated with altered actin localization. Older cells also had increased actin filament thickness. Depletion of heparan sulfate in young ECs elevated traction forces and actin filament thickness, while addition of heparan sulfate to the surface of aged ECs by treatment with angiopoietin-1 had the opposite effect. While inhibition of SIRT1 had no significant effect on traction forces or actin organization for young cells, activation of SIRT1 did reduce traction forces and increase peripheral actin in aged ECs. These results show that EC senescence increases traction forces and alters actin localization through changes to SIRT1 and the glycocalyx.

  10. Effects of ageing on orofacial fine force control and its relationship with parallel change in sensory perception.

    Science.gov (United States)

    Etter, Nicole M; Mckeon, Patrick O; Dressler, Emily V; Andreatta, Richard D

    2017-05-03

    Current theoretical models suggest the importance of a bidirectional relationship between sensation and production in the vocal tract to maintain lifelong speech skills. The purpose of this study was to assess age-related changes in orofacial skilled force production and to begin defining the orofacial perception-action relationship in healthy adults. Low-level orofacial force control measures (reaction time, rise time, peak force, mean hold force (N) and force hold SD) were collected from 60 adults (19-84 years). Non-parametric Kruskal Wallis tests were performed to identify statistical differences between force and group demographics. Non-parametric Spearman's rank correlations were completed to compare force measures against previously published sensory data from the same cohort of participants. Significant group differences in force control were found for age, sex, speech usage and smoking status. Significant correlational relationships were identified between labial vibrotactile thresholds and several low-level force control measures collected during step and ramp-and-hold conditions. These findings demonstrate age-related alterations in orofacial force production. Furthermore, correlational analysis suggests as vibrotactile detection thresholds increase, the ability to maintain low-level force control accuracy decreases. Possible clinical applications and treatment consequences of these findings for speech disorders in the ageing population are provided.

  11. 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.

  12. Understanding Driving Forces and Implications Associated with the Land Use and Land Cover Changes in Portugal

    Directory of Open Access Journals (Sweden)

    Bruno M. Meneses

    2017-02-01

    Full Text Available Understanding the processes of land use and land cover changes (LUCC and the associated driving forces is important for achieving sustainable development. This paper presents the LUCC in Portugal at the regional level (NUTS II from 1995 to 2010 and discusses the main driving forces and implications associated with these LUCC. The main objectives of this work are: (a to quantify the land use and land cover (LUC types (level I of LUC cartography by NUT II in Portugal for the years 1995, 2007 and 2010; (b to assess the spatio-temporal LUCC; and (c to identify and discuss the main driving forces of LUCC and corresponding implications based on correlations and Principal Components Analysis. The results revealed large regional and temporal LUCC and further highlighted the different and sometimes opposite time trends between neighboring regions. By associating driving forces to LUCC, different influences at the regional level were observed, namely LUCC into agriculture land derived from the construction of dams (Alentejo region, or the conversion of coniferous forest into eucalypt forest (Centre region associated with increased gross value added (GVA and employment in industry and forestry. Temporal differentiation was also observed, particularly in the settlements that expanded between 1995 and 2007 due to the construction of large infrastructures (e.g., highways, industrial complexes, or buildings, which is reflected on employment in industry and construction and respective GVA. However, certain LUCC have implications, particularly in energy consumption, for which different behavior between regions can be highlighted in this analysis, but also on land-use sustainability.

  13. Productivity changes in the Mediterranean Sea for the 21st century in response to changes in the regional atmospheric forcing

    Directory of Open Access Journals (Sweden)

    Diego M Macias

    2015-10-01

    Full Text Available The Mediterranean Sea is considered as a hotspot for climate change because of its location in the temperate region and because it is a semi-enclosed basin surrounded by highly populated and developed countries. Some expected changes include an increase in air temperature and changes in the periodicity and spatial distribution of rainfall. Alongside, demographic and politics changes will alter freshwater quantity and quality. All these changes will have an impact on the ecological status of marine ecosystems in the basin. We use a 3D hydrodynamic-biogeochemical coupled model of the entire Mediterranean Sea to explore potential changes in primary productivity (mean values and spatial distribution under two emission scenarios (rcp4.5 and rcp8.5.To isolate the effects of changes in atmospheric conditions alone, in this ensemble of simulations rivers conditions (water flow and nutrient concentrations are kept unchanged and equal to its climatological values for the last 10 years. Despite the significant warming trend, the mean integrated primary production rate in the entire basin remains almost unchanged. However characteristic spatial differences are consistently found in the different simulations. The western basin becomes more oligotrophic associated to a surface density decrease (increase stratification because of the influence of the Atlantic waters which prevents surface salinity to increase. In the eastern basin, on the contrary, all model runs simulates an increase in surface production linked to a density increase (less stratification because of the increasing evaporation rate. The simulations presented here demonstrate the basic response patterns of the Mediterranean Sea ecosystem to changing climatological conditions. Although unlikely, they could be considered as a ‘baseline’ of expected consequences of climatic changes on marine conditions in the Mediterranean.

  14. Natural and human forcing in recent geomorphic change; case studies in the Rio de la Plata basin.

    Science.gov (United States)

    Bonachea, Jaime; Bruschi, Viola M; Hurtado, Martín A; Forte, Luis M; da Silva, Mario; Etcheverry, Ricardo; Cavallotto, José L; Dantas, Marcilene F; Pejon, Osni J; Zuquette, Lázaro V; Bezerra, Maria Angélica de O; Remondo, Juan; Rivas, Victoria; Gómez-Arozamena, José; Fernández, Gema; Cendrero, Antonio

    2010-06-01

    An analysis of geomorphic system's response to change in human and natural drivers in some areas within the Río de la Plata basin is presented. The aim is to determine whether an acceleration of geomorphic processes has taken place in recent years and, if so, to what extent it is due to natural (climate) or human (land-use) drivers. Study areas of different size, socio-economic and geomorphic conditions have been selected: the Río de la Plata estuary and three sub-basins within its watershed. Sediment cores were extracted and dated ((210)Pb) to determine sedimentation rates since the end of the 19th century. Rates were compared with time series on rainfall as well as human drivers such as population, GDP, livestock load, crop area, energy consumption or cement consumption, all of them related to human capacity to disturb land surface. Data on river discharge were also gathered. Results obtained indicate that sedimentation rates during the last century have remained essentially constant in a remote Andean basin, whereas they show important increases in the other two, particularly one located by the São Paulo metropolitan area. Rates in the estuary are somewhere in between. It appears that there is an intensification of denudation/sedimentation processes within the basin. Rainfall remained stable or varied very slightly during the period analysed and does not seem to explain increases of sedimentation rates observed. Human drivers, particularly those more directly related to capacity to disturb land surface (GDP, energy or cement consumption) show variations that suggest human forcing is a more likely explanation for the observed change in geomorphic processes. It appears that a marked increase in denudation, of a "technological" nature, is taking place in this basin and leading to an acceleration of sediment supply. This is coherent with similar increases observed in other regions.

  15. 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.

  16. On the Rate of Structural Change in Scale Spaces

    DEFF Research Database (Denmark)

    Gustafsson, David Karl John; Pedersen, Kim Steenstrup; Lauze, Francois Bernard;

    2009-01-01

    We analyze the rate in which image details are suppressed as a function of the regularization parameter, using first order Tikhonov regularization, Linear Gaussian Scale Space and Total Variation image decomposition. The squared L2-norm of the regularized solution and the residual are studied...... as a function of the regularization parameter. For first order Tikhonov regularization it is shown that the norm of the regularized solution is a convex function, while the norm of the residual is not a concave function. The same result holds for Gaussian Scale Space when the parameter is the variance...

  17. Regional insolation forcing of late Quaternary climate change in the Southern Hemisphere.

    Science.gov (United States)

    Vandergoes, Marcus J; Newnham, Rewi M; Preusser, Frank; Hendy, Chris H; Lowell, Thomas V; Fitzsimons, Sean J; Hogg, Alan G; Kasper, Haino Uwe; Schlüchter, Christian

    2005-07-14

    In agreement with the Milankovitch orbital forcing hypothesis it is often assumed that glacial-interglacial climate transitions occurred synchronously in the Northern and Southern hemispheres of the Earth. It is difficult to test this assumption, because of the paucity of long, continuous climate records from the Southern Hemisphere that have not been dated by tuning them to the presumed Northern Hemisphere signals. Here we present an independently dated terrestrial pollen record from a peat bog on South Island, New Zealand, to investigate global and local factors in Southern Hemisphere climate changes during the last two glacial-interglacial cycles. Our record largely corroborates the Milankovitch model of orbital forcing but also exhibits some differences: in particular, an earlier onset and longer duration of the Last Glacial Maximum. Our results suggest that Southern Hemisphere insolation may have been responsible for these differences in timing. Our findings question the validity of applying orbital tuning to Southern Hemisphere records and suggest an alternative mechanism to the bipolar seesaw for generating interhemispheric asynchrony in climate change.

  18. Teaching and Learning about Force with a Representational Focus: Pedagogy and Teacher Change

    Science.gov (United States)

    Hubber, Peter; Tytler, Russell; Haslam, Filocha

    2010-01-01

    A large body of research in the conceptual change tradition has shown the difficulty of learning fundamental science concepts, yet conceptual change schemes have failed to convincingly demonstrate improvements in supporting significant student learning. Recent work in cognitive science has challenged this purely conceptual view of learning, emphasising the role of language, and the importance of personal and contextual aspects of understanding science. The research described in this paper is designed around the notion that learning involves the recognition and development of students’ representational resources. In particular, we argue that conceptual difficulties with the concept of force are fundamentally representational in nature. This paper describes a classroom sequence in force that focuses on representations and their negotiation, and reports on the effectiveness of this perspective in guiding teaching, and in providing insight into student learning. Classroom sequences involving three teachers were videotaped using a combined focus on the teacher and groups of students. Video analysis software was used to capture the variety of representations used, and sequences of representational negotiation. Stimulated recall interviews were conducted with teachers and students. The paper reports on the nature of the pedagogies developed as part of this representational focus, its effectiveness in supporting student learning, and on the pedagogical and epistemological challenges negotiated by teachers in implementing this approach.

  19. Land use change and its driving forces in alluvial-plain oasis

    Science.gov (United States)

    Xiao, Luxiang; Zhang, Zengxiang; Chen, Xi; Luo, Geping; Wen, Qingke

    2007-11-01

    Land use change and its driving factors are hot topics of global change research, and also important topics of sustainable development. This paper selected a small area in alluvial plain oasis in Xinjiang Autonomous region of China as the study area. Using Landsat TM data of 1987, 1998 and 2004, the dynamic process of the spatial-temporal characteristics of land use changes were analyzed to improve understanding and to find the driving forces of land use changes so that sustainable land utilization could be practiced. During the 17 years salt-alkali tolerant cropland, cereal cropland, vegetable-fruit land, and shrubbery, had decreased remarkably by 78.59%, 85.95%, 92.13%, 68.43%, respectively. Cotton-liquorice land, grape-hop land, planted forest, residential area in town, residential area in village, and saline-alkaline field had increased dramatically. The increased percentage received the value of 2432.11%, 10103.18%, 889.91%, 222.45%, 96.00%, 44.18%, respectively. By the logistic regression, the main driving factors were derived for each land use type. The advance of technology (fertilizer input, irrigation quota, and animal labor et al.) and market (unit are yield net) were the main driving factors. Policy, in a higher level, influenced the land use dynamics for all the land use changes.

  20. Salinity changes relative to the response to anthropogenic forcing and internal variability in the North Atlantic

    Science.gov (United States)

    Vinogradova, Nadya; Buckley, Martha

    2017-04-01

    Over the past few decades, surface waters in the subpolar North Atlantic have experienced substantial fluctuations, including periods of rapid cooling and freshening alternating with the periods of enhanced warming, salinification, and decreased circulation of the gyre. Since these waters feed the North Atlantic thermohaline circulation, such changes have the potential to impact the global ocean circulation and future climate states. A number of potential causes for the observed changes have been suggested, including those related to the strength of the ocean circulation and heat transports, as well as other factors, such as anthropogenic aerosol forcing or changes in surface fluxes. Here we assess how the observed warming/salinification events fit into the long-term picture, focusing on variations in upper-ocean salinity. Salinification of the subpolar North Atlantic may seem counter-intuitive to the reported long-term increase in freshwater supply to the region from river discharge and ice melting, sparking debates about whether the freshening of the subpolar gyre has ceased, and whether the recent salinification, if continued, will be able to forestall the projected slowdown of the overturning circulation. Using a suite of in situ salinity observations spanning the last 60 years, modern satellite salinity observations from Aquarius and SMOS missions, and multi-decadal realizations from global climate models, we estimate the likelihood of such salinity changes in the context of the historical record, contemporary estimates, and future projections. Results are discussed in terms of the probability of occurrence of a decade-long salinification in the presence of the background freshening in response to anthropogenic forcing. In particular, computed probabilities suggest that such "unusual" salinification events are plausible under the strong influence of internal, decadal-to-interdecadal variability.

  1. T, S, and U: Arctic Ocean Change in Response to Sea Ice Loss and Other Forcings

    Science.gov (United States)

    Steele, M.

    2015-12-01

    The Arctic Ocean is changing rapidly, partly in response to sea ice loss and partly from other forcings. Here we consider the three main parameters of physical oceanography: temperature, salinity, and momentum. With regard to temperature, the ocean is experiencing enhanced seasonal surface warming each summer as the ice pack retreats and thins. Some of this summer heat can persist through the winter below the surface mixed layer, although enhanced mixing and other processes can act against this survival. Deeper subsurface layers advected into the Arctic from the North Pacific and North Atlantic Oceans are also warming as these areas respond to warming trends and decadal climate variability. Arctic Ocean warming has implications for the mass balance of the sea ice pack, as well as both marine and coastal terrestrial ecosystems. With regard to salinity, the ocean has just begun to show an overall freshening signal, although with high spatial and temporal variance. This freshening is partly a result of sea ice melt, but also a response to global hydrologic and oceanographic changes. Arctic Ocean freshening enhances the surface stratification, which suppresses upward fluxes of heat and nutrients from below. It also reduces the transfer of momentum (i.e., the stress) from winds to the deep ocean. With regard to momentum, sea ice reduction has created a "looser" ice pack that allows more wind energy to enter the ocean. This effect opposes that of enhanced freshening/stratification when one considers mixing in the upper ocean; the sign and amplitude of the net result is a hot topic in the field. It should also be noted that surface stress in the summer season might actually be declining, as the rough ice pack transitions to a generally smoother sparse pack or open water. In summary, the Arctic Ocean is on the cusp of great change, largely (but not exclusively) forced by changes in the sea ice pack.

  2. ECONOMETRIC APPROACH TO DIFFERENCE EQUATIONS MODELING OF EXCHANGE RATES CHANGES

    Directory of Open Access Journals (Sweden)

    Josip Arnerić

    2010-12-01

    Full Text Available Time series models that are commonly used in econometric modeling are autoregressive stochastic linear models (AR and models of moving averages (MA. Mentioned models by their structure are actually stochastic difference equations. Therefore, the objective of this paper is to estimate difference equations containing stochastic (random component. Estimated models of time series will be used to forecast observed data in the future. Namely, solutions of difference equations are closely related to conditions of stationary time series models. Based on the fact that volatility is time varying in high frequency data and that periods of high volatility tend to cluster, the most successful and popular models in modeling time varying volatility are GARCH type models and their variants. However, GARCH models will not be analyzed because the purpose of this research is to predict the value of the exchange rate in the levels within conditional mean equation and to determine whether the observed variable has a stable or explosive time path. Based on the estimated difference equation it will be examined whether Croatia is implementing a stable policy of exchange rates.

  3. Forecasting rates of hydrocarbon discoveries in a changing economic environment

    Science.gov (United States)

    Schuenemeyer, J.H.; Attanasi, E.D.

    1984-01-01

    A method is presented for the estimation of undiscovered oil and gas resources in partially explored areas where economic truncation has caused some discoveries to go unreported; therefore distorting the relationship between the observed discovery size distribution and the parent or ultimate field size distribution. The method is applied to the UK's northern and central North Sea provinces. A discovery process model is developed to estimate the number and size distribution of undiscovered fields in this area as of 1983. The model is also used to forecast the rate at which fields will be discovered in the future. The appraisal and forecasts pertain to fields in size classes as small as 24 million barrels of oil equivalent (BOE). Estimated undiscovered hydrocarbon resources of 11.79 billion BOE are expected to be contained in 170 remaining fields. Over the first 500 wildcat wells after 1 January 1983, the discovery rate in this areas is expected to decline by 60% from 15 million BOE per wildcat well to six million BOE per wildcat well. ?? 1984.

  4. [Climatic change and public health: scenarios after the coming into force of the Kyoto Protocol].

    Science.gov (United States)

    Ballester, Ferran; Díaz, Julio; Moreno, José Manuel

    2006-03-01

    According to the reports of the intergovernmental panel for climatic change (IPCC) human beings of the present and near future are going to experiment, in fact we are already experimenting, important changes in the world climate. Conscious of the magnitude of the problem, international organizations have taken a series of initiatives headed to stop the climatic change and to reduce its impact. This willingness has been shaped into the agreements established in the Kyoto protocol, where countries commit to reduce greenhouse-effect gas emissions. Kyoto protocol has come into force on February 16th 2005 with the support of 141 signing countries. Among the major worries are the effects which climatic change may have upon health, such as: 1) changes in the morbidity- mortality related to temperature; 2) Effects on health related with extreme meteorological events (tornados, storms, hurricanes and extreme raining); 3) Air pollution and increase of associated health effects; d) Diseases transmitted by food and water and 4) Infectious diseases transmitted by vectors and by rodents. Even if all the countries in the world committed to the Kyoto Protocol, some consequences of the climatic change will be inevitable; among them some will have a negative impact on health. It would be necessary to adapt a key response strategy to minimize the impacts of climatic change and to reduce, at minimum cost, its adverse effects on health. From the Public Health position, a relevant role can and must be played concerning the understanding of the risks for health of such climatic changes, the design of surveillance systems to evaluate possible impacts, and the establishment of systems to prevent or reduce damages as well as the identification and development of investigation needs.

  5. Global Changes And Tree Growth Rate In The Amazon Forest

    Science.gov (United States)

    Camargo, P. B.; Vieira, S. A.; Trumbore, S. E.

    2003-12-01

    A better understanding of the variations in the dynamics and structure of trees in tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon. In general, tropical forests have been treated as if all trees behaved similarly, and little is known about how forests vary across the large extent of the Amazon basin. Our data show large differences in forest structure, biomass, and tree growth rates among plots under study in three locations in Brazil: ZF-2 Bionte/Jacaranda plots \\(Manaus\\), Catuaba Reserve \\(Rio Branco\\), and Tapaj¢s National Forest \\(Santarém\\). These locations span an east-west transect of the Amazon basin with different dry-season lengths. The number of stems >10cm diameter and stocks of C in aboveground biomass are the highest in Manaus \\(626ha-1, 180.1Mg.C.ha-1\\), than Rio Branco \\(466ha-1, 122.1Mg.C.ha-1\\) or Santarém \\(460ha-1, 140.6Mg.C.ha-1\\). Estimates of mean annual accumulation of C ranged from 1.6 \\(Manaus\\) and 2.5 \\(Rio Branco\\) to 2.8Mg.C.ha-1.yr-1 \\(Santarém\\). Trees in the 10-30cm diameter-size showed the highest accumulation of C \\(38%, 55%, and 56% - Manaus, Rio Branco, and Santarém, respectively\\). Our results showed marked seasonal growth, with the highest growth rates in the wet-season and the lowest growth rates in the dry-season. This effect was most evident for trees with diameter >50cm. The comparison of the three areas investigated suggests that forests experiencing a longer dry-season have larger annual diameter growth increments for individual trees. Tree average age was larger in Manaus where the increment was smaller. In all the three areas it was found specimens with DBH smaller than 30cm, but with ages over 200 years. It was found a specimen of 17 cm of DBH and age of 920 years. The fact that small trees can reach old ages may alter the scope of the present forest management planning whose focus is tree species of economical interest and the time the

  6. 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...

  7. Decadal Changes in Arctic Radiative Forcing from Aerosols and Tropospheric Ozone

    Science.gov (United States)

    Breider, T. J.; Mickley, L. J.; Jacob, D. J.; Payer Sulprizio, M.; Croft, B.; Ridley, D. A.; Ge, C.; Yang, Q.; Bitz, C. M.; McConnell, J.; Sharma, S.; Skov, H.; Eleftheriadis, K.

    2014-12-01

    Annual average Arctic sea ice coverage has declined by 3.6% per decade since the 1980s, but factors driving this trend are uncertain. Long-term surface observations and ice core records suggest recent, large declines in the Arctic atmospheric burden of sulfate aerosol, which may account in part for the warming trend. The decline in black carbon (BC) aerosol in the Arctic during the same period may partly offset the warming due to decreases in sulfate. Here we use the GEOS-Chem chemical transport model together with a detailed inventory of historical anthropogenic trace gas and primary aerosol emissions to quantify changes in Arctic radiative forcing from tropospheric ozone and aerosol between 1980 and 2010. Previous studies have reported an increasing trend in observed ozone at 500 hPa over Canada, but our simulation shows no significant trend. Over Europe, good agreement is found with observed long-term trends in sulfate in surface air (observed = -0.14±0.02 μg m-3 yr-1, model = -0.13±0.01 μg m-3 yr-1), while the observed trend in sulfate in precipitation (-0.20±0.03 μg m-3 yr-1) is underestimated by 40%. At Alert, the timing of the observed decline in sulfate after 1991 is well captured in the simulation, but the observed trend between 1991 and 2001 (-36.3±4.1 ng m-3 yr-1) is underestimated by 26%. BC observations at remote Arctic surface stations are biased low throughout 1980-2010 by a factor of 2. At Greenland ice cores, observed 1980-2010 trends in sulfate deposition are underestimated by 35%. The smaller model bias in observed sulfate and BC deposition at ice cores in southern Greenland (5% and 65%) compared to northern Greenland (56% and 90%) indicates greater uncertainty in pollution emissions from Eurasian sources. We estimate a surface radiative forcing from atmospheric aerosols in the Arctic during 2008 of -0.51 W m-2. The forcing is largest in spring (-1.36 W m-2) and dominated by sulfate aerosol (87%). We will quantify the contributions to the

  8. 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.

  9. Non-Kyoto radiative forcing in long-run greenhouse gas emissions and climate change scenarios

    NARCIS (Netherlands)

    Rose, S.K.; Kriegler, E.; Bibas, R.; Calvin, K.; Popp, A.; van Vuuren, D.P.; Weyant, J.

    2014-01-01

    Climate policies must consider radiative forcing from Kyoto greenhouse gases, as well as other forcing constituents, such as aerosols and tropospheric ozone that result from air pollutants. Non-Kyoto forcing constituents contribute negative, as well as positive forcing, and overall increases in tota

  10. Non-Kyoto radiative forcing in long-run greenhouse gas emissions and climate change scenarios

    NARCIS (Netherlands)

    Rose, S.K.; Kriegler, E.; Bibas, R.; Calvin, K.; Popp, A.; van Vuuren, D.P.; Weyant, J.

    2014-01-01

    Climate policies must consider radiative forcing from Kyoto greenhouse gases, as well as other forcing constituents, such as aerosols and tropospheric ozone that result from air pollutants. Non-Kyoto forcing constituents contribute negative, as well as positive forcing, and overall increases in

  11. 7 CFR 3575.80 - Interest rate changes after loan closing.

    Science.gov (United States)

    2010-01-01

    ... guarantee except the normal fluctuations in approved variable interest rate loans. ... 7 Agriculture 15 2010-01-01 2010-01-01 false Interest rate changes after loan closing. 3575.80..., DEPARTMENT OF AGRICULTURE GENERAL Community Programs Guaranteed Loans § 3575.80 Interest rate changes...

  12. Upper Incisor Changes Due to Modifying the Point of Application of Forces during Space Closure in MBT Technique

    Directory of Open Access Journals (Sweden)

    H. Ravanmehr

    2004-06-01

    Full Text Available Statement of Problem: A recent technique (MBT has been introduced for easy and efficient orthodontic treatment by means of straight wire fixed appliances. Although this technique has many advantages, in space closure stage causes up righting problem in upper incisors, which should be adjusted by applying additional torque in anterior region.Purpose: The purpose of this clinical trial was to determine whether there is a significant difference in final incisor inclination (torque of two groups one treated with MBT technique and the other by changing the point of application of the closing force (in anterior region.Materials and Methods: Twelve patients (8 girls, 4 boys with Cl I malocclusion and crowding, whom were candidate for first premolars extraction, were selected.For space closure, 6 anterior teeth (canine to canine in upper and lower jaws ligated and the applied force was from the hooks on canines to hooks on the first molars.After space closure the results compared with the results of a previous study which treatment plan was according to original MBT technique (anterior hooks soldered to arch wire. Forces applied randomly among quadrants by NiTi coil spring (American Orthodontics Co. or active tie backs with elastic modules (Dentaurum Co.Results: The results showed a statistically significant difference between final torques of two techniques (P=0.0001. Also, the rate of space closure with NiTi coils was significantly greater than active tie back (P=0.0001.Conclusion: Anchorage loss in two groups compared and the results indicated significantly lower anchorage loss in NiTi coil spring group (P=0.035.

  13. Rate of change in early Huntington's disease: a clinicometric analysis.

    Science.gov (United States)

    Meyer, Christina; Landwehrmeyer, Bernhard; Schwenke, Carsten; Doble, Adam; Orth, Michael; Ludolph, Albert C

    2012-01-01

    Sensitive outcome measures for patients with Huntington's disease (HD) are required for future clinical trials. Longitudinal data were collected from a 3-year study of 379 patients suffering from early HD who were not treated by antipsychotics. Progression of UHDRS item scores was evaluated by linear regression and slope, whereas correlation coefficient, standard error, and P values were estimated on the basis of the data of eight evaluations from screening to study end (36 months). For the functional assessment dimension, the proportion of "no" responses at baseline and at study end was determined. Linear progression was observed for the motor score and for all three functional measures (i.e., functional assessment score, independence assessment score, and total functional capacity score). In contrast, there was little evidence for progression of the behavioral assessment score over the study period, whereas the cognitive assessment score was intermediate. Twenty-two motor-score items showed linear progression, with a slope of >0.003. These included all chorea items, finger tapping and pronation/supination (left and right), gait, tongue protrusion, and tandem walking. Different symptom domains and individual items evolved at different rates in this group of patients suffering from early HD. It may be possible to select sensitive items to create a simplified version of the UHDRS, which would be more efficient and more sensitive for the assessment of disease progression in clinical trials and natural history studies.

  14. Spatiotemporal variation of surface shortwave forcing from fire-induced albedo change in interior Alaska

    Science.gov (United States)

    Huang, Shengli; Dahal, Devendra; Liu, Heping; Jin, Suming; Young, Claudia J.; Liu, Shuang; Liu, Shu-Guang

    2015-01-01

    The albedo change caused by both fires and subsequent succession is spatially heterogeneous, leading to the need to assess the spatiotemporal variation of surface shortwave forcing (SSF) as a component to quantify the climate impacts of high-latitude fires. We used an image reconstruction approach to compare postfire albedo with the albedo assuming fires had not occurred. Combining the fire-caused albedo change from the 2001-2010 fires in interior Alaska and the monthly surface incoming solar radiation, we examined the spatiotemporal variation of SSF in the early successional stage of around 10 years. Our results showed that while postfire albedo generally increased in fall, winter, and spring, some burned areas could show an albedo decrease during these seasons. In summer, the albedo increased for several years and then declined again. The spring SSF distribution did not show a latitudinal decrease from south to north as previously reported. The results also indicated that although the SSF is usually largely negative in the early successional years, it may not be significant during the first postfire year. The annual 2005-2010 SSF for the 2004 fire scars was -1.30, -4.40, -3.31, -4.00, -3.42, and -2.47 Wm-2. The integrated annual SSF map showed significant spatial variation with a mean of -3.15 Wm-2 and a standard deviation of 3.26 Wm-2, 16% of burned areas having positive SSF. Our results suggest that boreal deciduous fires would be less positive for climate change than boreal evergreen fires. Future research is needed to comprehensively investigate the spatiotemporal radiative and non-radiative forcings to determine the effect of boreal fires on climate.

  15. An exploration of ozone changes and their radiative forcing prior to the chlorofluorocarbon era

    Directory of Open Access Journals (Sweden)

    D. T. Shindell

    2002-01-01

    Full Text Available Using historical observations and model simulations, we investigate ozone trends prior to the mid-1970s onset of halogen-induced ozone depletion. Though measurements are quite limited, an analysis based on multiple, independent data sets (direct and indirect provides better constraints than any individual set of observations. We find that three data sets support an apparent long-term stratospheric ozone trend of -7.2 ± 2.3 DU during 1957-1975, which modeling attributes primarily to water vapor increases. The results suggest that 20th century stratospheric ozone depletion may have been roughly 50% more than is generally supposed. Similarly, three data sets support tropospheric ozone increases over polluted Northern Hemisphere continental regions of 8.2 ± 2.1 DU during this period, which are mutually consistent with the stratospheric trends. As with paleoclimate data, which is also based on indirect proxies and/or limited spatial coverage, these results must be interpreted with caution. However, they provide the most thorough estimates presently available of ozone changes prior to the coincident onset of satellite data and halogen dominated ozone changes. If these apparent trends were real, the radiative forcing by stratospheric ozone since the 1950s would then have been -0.15 ± 0.05 W/m2, and -0.2 W/m2 since the preindustrial. For tropospheric ozone, it would have been 0.38 ± 0.10 W/m2 since the late 1950s. Combined with even a very conservative estimate of tropospheric ozone forcing prior to that time, this would be larger than current estimates since 1850 which are derived from models that are even less well constrained. These calculations demonstrate the importance of gaining a better understanding of historical ozone changes.

  16. 47 CFR 43.43 - Reports of proposed changes in depreciation rates.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Reports of proposed changes in depreciation... Reports of proposed changes in depreciation rates. (a) Each communication common carrier with annual..., before making any changes in the depreciation rates applicable to its operated plant, file with...

  17. 47 CFR 1.787 - Reports of proposed changes in depreciation rates.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Reports of proposed changes in depreciation... Reports and Requests § 1.787 Reports of proposed changes in depreciation rates. Carriers shall file reports regarding proposed changes in depreciation rates as required by part 43 of this chapter....

  18. The effect of nonlinearity in CO2 heating rates on the attribution of stratospheric ozone and temperature changes

    Directory of Open Access Journals (Sweden)

    T. G. Shepherd

    2009-11-01

    Full Text Available An analysis of the attribution of past and future changes in stratospheric ozone and temperature to anthropogenic forcings is presented. The analysis is an extension of the study of Shepherd and Jonsson (2008 who analyzed chemistry-climate simulations from the Canadian Middle Atmosphere Model (CMAM and attributed both past and future changes to changes in the external forcings, i.e. the abundances of ozone-depleting substances (ODS and well-mixed greenhouse gases. The current study is based on a new CMAM dataset and includes two important changes. First, we account for the nonlinear radiative response to changes in CO2. It is shown that over centennial time scales the radiative response in the upper stratosphere to CO2 changes is significantly nonlinear and that failure to account for this effect leads to a significant error in the attribution. To our knowledge this nonlinearity has not been considered before in attribution analysis, including multiple linear regression studies. For the regression analysis presented here the nonlinearity was taken into account by using CO2 heating rate, rather than CO2 abundance, as the explanatory variable. This approach yields considerable corrections to the results of the previous study and can be recommended to other researchers. Second, an error in the way the CO2 forcing changes are implemented in the CMAM was corrected, which significantly affects the results for the recent past. As the radiation scheme, based on Fomichev et al. (1998, is used in several other models we provide some description of the problem and how it was fixed.

  19. Projected Changes in Evapotranspiration Rates over Northeast Brazil

    Science.gov (United States)

    Costa, Alexandre; Guimarães, Sullyandro; Vasconcelos, Francisco, Jr.; Sales, Domingo; da Silva, Emerson

    2015-04-01

    Climate simulations were performed using a regional model (Regional Atmospheric Modeling System, RAMS 6.0) driven by data from one of the CMIP5 models (Hadley Centre Global Environmental Model, version 2 - Earth System, HadGEM2-ES) over two CORDEX domains (South America and Central America) for the heavy-emission scenario (RCP8.5). Potential evapotranspiraion data from the RCM and from the CMIP5 global models were analyzed over Northeast Brazil, a semiarid region with a short rainy season (usually February to May in its northern portion due to the seasonal shift of the Intertropical Convergence Zone) and over which droughts are frequent. Significant changes in the potential evapotranspiration were found, with most models showing a increasing trend along the 21st century, which are expected to alter the surface water budget, increasing the current water deficit (precipitation is currently much smaller than potential evapotranspiration). Based on the projections from the majority of the models, we expect important impacts over local agriculture and water resources over Northeast Brazil.

  20. Choice with frequently changing food rates and food ratios.

    Science.gov (United States)

    Baum, William M; Davison, Michael

    2014-03-01

    In studies of operant choice, when one schedule of a concurrent pair is varied while the other is held constant, the constancy of the constant schedule may exert discriminative control over performance. In our earlier experiments, schedules varied reciprocally across components within sessions, so that while food ratio varied food rate remained constant. In the present experiment, we held one variable-interval (VI) schedule constant while varying the concurrent VI schedule within sessions. We studied five conditions, each with a different constant left VI schedule. On the right key, seven different VI schedules were presented in seven different unsignaled components. We analyzed performances at several different time scales. At the longest time scale, across conditions, behavior ratios varied with food ratios as would be expected from the generalized matching law. At shorter time scales, effects due to holding the left VI constant became more and more apparent, the shorter the time scale. In choice relations across components, preference for the left key leveled off as the right key became leaner. Interfood choice approximated strict matching for the varied right key, whereas interfood choice hardly varied at all for the constant left key. At the shortest time scale, visit patterns differed for the left and right keys. Much evidence indicated the development of a fix-and-sample pattern. In sum, the procedural difference made a large difference to performance, except for choice at the longest time scale and the fix-and-sample pattern at the shortest time scale. © Society for the Experimental Analysis of Behavior.

  1. 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.

  2. Indian Ocean sea surface temperature variability and change since 1960s: forcing and process

    Science.gov (United States)

    Han, W.; Meehl, G. A.; Hu, A.

    2005-12-01

    Indian Ocean sea surface temperature (SST) variability and change since 1960s are investigated using global coupled models,the Community Climate System Model version 3 (CCSM3) and parallel climate model (PCM). Results from the CCSM3 and a series of PCM experiments are analyzed in order to understand the roles played by internal variability, human-induced warming, and external forcing in causing the SST variations. To consolidate the model results, the simple Ocean model Data Assimilation (SODA) products are also analyzed. The results suggest that the SST in both the south and north Indian Ocean (IO) has an increasing trend. Overlying on this trend is decadal variability. Consistent with previous studies, the warming trend results mainly from the human-induced increased green house gases, which increase downward longwave fluxes. Interestingly, warming of the upper tropical and subtropical basins is accomanied by cooling in higher-latitudes in the Antarctic Circumpolar Current (ACC) region, which results from the reduced southward heat transports by weakened the subtropical cells (STCs). This colder, ACC water can enter the IO via deep layers in the south and then shoals upward to the thermocline layer in the tropical Indian Ocean, causing a distinct vertical structrure: with warming in the near surface and below the thermocline and cooling in the thermocline. The SST decadal variability, however, is caused primarily by external forcing, due to a combined effect of surface heat flux and lateral heat transport. Internal variability of the coupled system also plays a role.

  3. Expectations, open market operations, and changes in the federal funds rate / Commentary

    National Research Council Canada - National Science Library

    John B Taylor; Athanasios Orphanides

    2001-01-01

    ... (2000) to explain the demand for Fed balances. The model shows how changes in the target for the federal funds rate can sometimes affect the actual funds rate even without any current open market operations...

  4. Assessment of changes in gait parameters and vertical ground reaction forces after total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Bhargava P

    2007-01-01

    the control group. Vertical ground reaction force variables are also altered. Conclusion: Significant changes ( P value < .05 in gait parameters and vertical ground reaction forces show that gait pattern is not normalized after THR and weight-bearing is not equally shared by both hips. Patient walks with residual antalgic gait even after surgery, which results in abnormal loading around hip joints and the integrity of the prosthesis fixation could be compromised.

  5. Monitoring the elasticity changes of HeLa cells during mitosis by atomic force microscopy

    Science.gov (United States)

    Jiang, Ningcheng; Wang, Yuhua; Zeng, Jinshu; Ding, Xuemei; Xie, Shusen; Yang, Hongqin

    2016-10-01

    Cell mitosis plays a crucial role in cell life activity, which is one of the important phases in cell division cycle. During the mitosis, the cytoskeleton micro-structure of the cell changed and the biomechanical properties of the cell may vary depending upon different mitosis stages. In this study, the elasticity property of HeLa cells during mitosis was monitored by atomic force microscopy. Also, the actin filaments in different mitosis stages of the cells were observed by confocal imaging. Our results show that the cell in anaphase is stiffer than that in metaphase and telophase. Furthermore, lots of actin filaments gathered in cells' center area in anaphase, which contributes to the rigidity of the cell in this phase. Our findings demonstrate that the nano-biomechanics of living cells could provide a new index for characterizing cell physiological states.

  6. Changes in forcing factors affecting coastal and shallow water erosion in the future Arctic climate change projections.

    Science.gov (United States)

    Dobrynin, Mikhail; Razumov, Sergey; Brovkin, Victor; Ilyina, Tatiana; Grigoriev, Mikhail

    2016-04-01

    Driving factors of seabed and coastal erosion in the Arctic can be classified as thermal and mechanical. Thermal factors such as air and ocean temperatures affect the seabed and coastal ground temperatures. Mechanical factors such as ocean currents and surface gravity waves contribute to the seabed and costal erosion due to shear stress. Due to polar amplification, the Arctic experiences strong increase in air and water temperature, sea-ice loss and changes in the ocean and atmospheric circulation, temperature and wind distribution. These climatic changes lead to changes in factors driving seabed and coastal erosion, which is expected to accelerate in the shallow Arctic regions such as the Laptev sea and East Siberian sea. In these regions, the coastal line to a large extent consists of frozen rocks, sediments and organic soils including ground ice. The increase of erosion rate of the coastal line will increase the release of organic and inorganic matter from thawed permafrost. Dynamics of thermal and mechanical drivers of seabed and coastal erosion in the present and future climate change (RCP8.5 scenario) simulated by the CMIP5 version of the MPI Earth system model and wave model WAM will be presented. Special attention will be given to changes in the air temperature, wind dynamics and development of new waves system in the ``ice-free'' Arctic and its role in the seabed and coastal erosion.

  7. Climate forcing and air quality change due to regional emissions reductions by economic sector

    Directory of Open Access Journals (Sweden)

    D. Shindell

    2008-06-01

    Full Text Available We examine the air quality (AQ and radiative forcing (RF response to emissions reductions by economic sector for North America and developing Asia in the CAM and GISS composition/climate models. Decreases in annual average surface particulate are relatively robust, with intermodel variations in magnitude typically <30% and very similar spatial structure. Surface ozone responses are small and highly model dependent. The largest net RF results from reductions in emissions from the North America industrial/power and developing Asia domestic fuel burning sectors. Sulfate reductions dominate the first case, for which intermodel variations in the sulfate (or total aerosol optical depth (AOD responses are ~30% and the modeled spatial patterns of the AOD reductions are highly correlated (R=0.9. Decreases in BC dominate the developing Asia domestic fuel burning case, and show substantially greater model-to-model differences. Intermodel variations in tropospheric ozone burdens are also large, though aerosol changes dominate those cases with substantial net climate forcing. The results indicate that across-the-board emissions reductions in domestic fuel burning in developing Asia and in surface transportation in North America are likely to offer the greatest potential for substantial, simultaneous improvement in local air quality and near-term mitigation of global climate change via short-lived species. Conversely, reductions in industrial/power emissions have the potential to accelerate near-term warming, though they would improve AQ and have a long-term cooling effect on climate. These broad conclusions appear robust to intermodel differences.

  8. 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.

  9. 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.

  10. 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 ...

  11. Field Test Evaluation of Effect on Cone Resistance Caused by Change in Penetration Rate

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2012-01-01

    This paper presents how a change in cone penetration rate affects the measured cone resistance during cone penetration testing in silty soils. Regardless of soil, type the standard rate of penetration is 20 mm/s and it is generally accepted that undrained penetration occurs in clay while drained...... in the laboratory. A change in the measured cone resistance occurs by lowering the penetration rate. This is caused by the changes in drainage conditions. Compared to the normal penetration rate of 20 mm/s, this paper illustrates that lowering the penetration rate leads to an increase in the cone resistance from 1...

  12. Understanding Rates of Change: How have climate transitions during the Holocene driven the pace of vegetation change in California ecosystems?

    Science.gov (United States)

    Anderson, L.; Wahl, D.; Barron, J. A.

    2016-12-01

    A fundamental aspect of ecosystem response to global climate change is the rate at which systems can change, determined in large part by the timing and magnitude of changes in climate parameters. Reorganization in atmosphere/ocean dynamics of the North Pacific on millennial to centennial time scales has resulted in climate change in western North America. The seasonality of the position and intensity of the Aleutian Low and the North Pacific High, Pacific SSTs, and related high frequency variability (ENSO, PDO) all strongly influence temperature and precipitation regimes of western North America. This study assesses the rate of vegetation response to climate change in the western United States. Here we present preliminary reconstructions of rates of vegetation change in California from 11k cal. BP to the present. Research questions include: Do increased rates of ecosystem transformation correspond with times of marked reorganization in climate dynamics? What is the geographic distribution of rates of change, and how does that distribution vary through time? Rate of change is defined as the ratio of the difference in abundances of a fixed array of pollen taxa between adjacent samples within a pollen record over time. The measure of difference was determined using the VEGAN package in R and applying the Bray-Curtis measure. Analyses are based on publicly available data from published fossil pollen studies. Our initial results suggest broad coherence of increased change rates at around 3.5k and 6k cal. BP. Future work will focus on evaluating potential refinements of the filter applied to the pollen data and standardization of the sample intervals, as well as on expansion of the data sets analyzed to include the Pacific Northwest and the Southwest regions of North America in order to provide a more comprehensive analysis of past change rates in the western US.

  13. [Spatiotemporal patterns and driving forces of land use change in industrial relocation area: a case study of old industrial area in Tiexi of Shenyang, Northeast China].

    Science.gov (United States)

    Wang, Mei-Ling; Bing, Long-Fei; Xi, Feng-Ming; Wu, Rui; Geng, Yong

    2013-07-01

    Based on the QuickBird remote sensing images and with the support of GIS, this paper analyzed the spatiotemporal characteristics of land use change and its driving forces in old industrial area of Tiexi, Shenyang City of Liaoning Province in 2000-2010. During the study period, the industrial and mining warehouse land pattern had the greatest change, evolving from the historical pattern of residential land in the south and of industrial land in the north into residential land as the dominant land use pattern. In the last decade, the residential land area increased by 9%, mainly transferred from the industrial and mining warehouse land located in the north of Jianshe Road, while the industrial and mining warehouse land area decreased by 20%. The land areas for the commercial service and for the administrative and public services were increased by 1.3% and 3.1%, respectively. The land area for construction had a greater change, with an overall change rate being 76.9%. The land use change rate in 2000-2005 was greater than that in 2005-2010. National development strategies and policies, regional development planning, administrative reform, and industrial upgrading were the main driving forces of the land use change in old industrial area of Tiexi.

  14. Changes in muscle activation and force generation patterns during cycling movements because of low-intensity squat training with slow movement and tonic force generation.

    Science.gov (United States)

    Tanimoto, Michiya; Arakawa, Hiroshi; Sanada, Kiyoshi; Miyachi, Motohiko; Ishii, Naokata

    2009-11-01

    Our previous studies showed that relatively low-load (approximately 50-60% 1 repetition maximum [1RM]) resistance training with slow movement and tonic force generation (LST) significantly increased muscle size and strength. However, LST is a very specific movement that differs from natural movements associated with sport activities and activities of daily life, and therefore, it might have some unfavorable effects on dynamic sport movement. We investigated the effects of LST on muscle activity and force generation patterns during cycling movement as a representative dynamic sports movement. Twenty-four healthy young men who were not in the habit of bicycle riding and did not have a history of regular resistance training were randomly assigned to the LST (approximately 60% 1RM load, 3-second lifting, and 3-second lowering movement without a relaxing phase: n = 8), a high-intensity exercise at normal speed (HM) group (85% 1RM load, 1-second lifting, 1-second lowering, and 1-second relaxed movement: n = 8), or sedentary control (CON, n = 8) group. Subjects in the training groups performed vertical squats by the assigned method. Exercise sessions consisted of 3 sets and were performed twice a week for 13 weeks. Pre- and posttraining muscle activation and force generation patterns during the cycling movements were evaluated by the coefficient of variation (CV) of the rectified electromyographic (EMG) wave from the vastus lateralis and CV of pedaling force. Both the CV of the rectified EMG and of pedaling force decreased significantly in the LST group (-21 and -18%, p < 0.05, respectively), whereas there were no significant changes in either the HN or the CON group. This decrease in CV in the LST group could mean that muscle activity and force generation during cycling movement have become more tonic. This result following LST may have an unfavorable effect on cycling movement and other dynamic sports movements.

  15. The Dynamic Change in the Total Arable Land and its Driving Forces in Tongling City of Anhui Province

    Institute of Scientific and Technical Information of China (English)

    Yan; LI; Zhongxiang; YU

    2014-01-01

    According to Anhui Statistical Yearbook( 2003-2012) and the second national land survey data,this article analyzes the current situation of land use and the dynamic change in the total arable land in Tongling City. On the basis of this,using grey relational analysis,this article analyzes the driving forces for arable land changes in Tongling City. Studies show that population growth,the improvement of level of urbanization and the rapid development of the economy are the main driving forces for arable land changes. Based on the findings,the strategies are put forth in order to ensure the dynamic balance of total arable land.

  16. 75 FR 43944 - Defense Science Board; Task Force on Trends and Implications of Climate Change for National and...

    Science.gov (United States)

    2010-07-27

    ... Climate Change for National and International Security will meet in closed session August 18-19, and... Office of the Secretary Defense Science Board; Task Force on Trends and Implications of Climate Change for National and International Security AGENCY: Department of Defense (DoD). ACTION: Notice...

  17. 75 FR 34438 - Defense Science Board Task Force on Trends and Implications of Climate Change for National and...

    Science.gov (United States)

    2010-06-17

    ... Change for National and International Security will meet in closed session on July 14-15 and on July 29... of the Secretary Defense Science Board Task Force on Trends and Implications of Climate Change for National and International Security AGENCY: Department of Defense (DoD). ACTION: Notice of...

  18. Predicting demographically sustainable rates of adaptation: can great tit breeding time keep pace with climate change?

    Science.gov (United States)

    Gienapp, Phillip; Lof, Marjolein; Reed, Thomas E; McNamara, John; Verhulst, Simon; Visser, Marcel E

    2013-01-19

    Populations need to adapt to sustained climate change, which requires micro-evolutionary change in the long term. A key question is how the rate of this micro-evolutionary change compares with the rate of environmental change, given that theoretically there is a 'critical rate of environmental change' beyond which increased maladaptation leads to population extinction. Here, we parametrize two closely related models to predict this critical rate using data from a long-term study of great tits (Parus major). We used stochastic dynamic programming to predict changes in optimal breeding time under three different climate scenarios. Using these results we parametrized two theoretical models to predict critical rates. Results from both models agreed qualitatively in that even 'mild' rates of climate change would be close to these critical rates with respect to great tit breeding time, while for scenarios close to the upper limit of IPCC climate projections the calculated critical rates would be clearly exceeded with possible consequences for population persistence. We therefore tentatively conclude that micro-evolution, together with plasticity, would rescue only the population from mild rates of climate change, although the models make many simplifying assumptions that remain to be tested.

  19. A linear description of shortening induced changes in isometric length-force characteristics of rat muscle

    OpenAIRE

    Meijer, K; Grootenboer, H.J.; Koopman, H.F.J.M.; Huijing, P.A.

    1996-01-01

    Active muscle shortening reduces the isometric force potential of muscle. This observation indicates that the isometric length-force characteristics are altered during muscle shortening. Post-shortening decrease in isometric force depends on starting length, shortening amplitude and shortening velocity. In the present study, post-shortening decrease in isometric force was determined after isokinetic contractions with various shortening amplitudes initiated from different lengths of rat medial...

  20. Muscle specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat

    DEFF Research Database (Denmark)

    Olesen, Annesofie Thorup; Jensen, Bente Rona; Uhlendorf, Toni L;

    2014-01-01

    , the extent of this interaction was not different in the spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes seen for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate......The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO) and plantaris (PL) were assessed in anesthetized spastic...... and normally-developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA) was investigated. Active length-force characteristics of spastic GA and PL were narrower...

  1. A linear description of shortening induced changes in isometric length-force characteristics of rat muscle

    NARCIS (Netherlands)

    Meijer, K.; Grootenboer, H.J.; Koopman, H.F.J.M.; Huijing, P.A.

    1996-01-01

    Active muscle shortening reduces the isometric force potential of muscle. This observation indicates that the isometric length-force characteristics are altered during muscle shortening. Post-shortening decrease in isometric force depends on starting length, shortening amplitude and shortening veloc

  2. Mid-latitude ozone changes: studies with a 3-D CTM forced by ERA-40 analyses

    Directory of Open Access Journals (Sweden)

    W. Feng

    2007-01-01

    Full Text Available We have used an off-line three-dimensional (3-D chemical transport model (CTM to study long-term changes in stratospheric O3. The model was run from 1977–2004 and forced by ECMWF ERA-40 and operational analyses. Model runs were performed to examine the impact of increasing halogens and additional stratospheric bromine from short-lived source gases. The analyses capture much of the observed interannual variability in column ozone, but there are also unrealistic features. In particular the ERA-40 analyses cause a large positive anomaly in northern hemisphere (NH column O3 in the late 1980s. Also, the change from ERA-40 to operational winds at the start of 2002 introduces abrupt changes in some model fields (e.g. temperature, ozone which affect analysis of trends. The model reproduces the observed column increase in NH mid-latitudes from the mid 1990s. Analysis of a run with fixed halogens shows that this increase is not due to a significant decrease in halogen-induced loss, i.e. is not an indication of recovery. The model predicts only a small decrease in halogen-induced loss after 1999. In the upper stratosphere, despite the modelled turnover of chlorine around 1999, O3 does not increase because of the effects of increasing ECMWF temperatures, decreasing modelled CH4 at this altitude, and abrupt changes in the SH temperatures at the end of the ERA-40 period. The impact of an additional 5 pptv stratospheric bromine from short-lived species decreases mid-latitude column O3 by about 10 DU. However, the impact on the modelled relative O3 anomaly is generally small except during periods of large volcanic loading.

  3. Do additional inputs change maximal voluntary motor unit firing rates after spinal cord injury?

    Science.gov (United States)

    Zijdewind, Inge; Gant, Katie; Bakels, Rob; Thomas, Christine K

    2012-01-01

    Motor unit firing frequencies are low during maximal voluntary contractions (MVCs) of human thenar muscles impaired by cervical spinal cord injury (SCI). This study aimed to examine whether thenar motor unit firing frequencies increase when driven by both maximal voluntary drive and other concurrent inputs compared with an MVC alone. Motor unit firing rates, force, and surface electromyographic activity (EMG) were compared across 2 contractions: (a) MVC alone and (b) MVC combined with another input (combination contraction). Other inputs (conditions) included vibration, heat, or cold applied to the anterior surface of the forearm, electrical stimulation delivered to the anterior surface of the middle finger, a muscle spasm, or a voluntary contraction of the contralateral thenar muscles against resistance. The maximal firing frequency (n = 68 units), force, and electromyographic activity (n = 92 contraction pairs) were all significantly higher during the combined contractions compared with MVCs alone. There was a 3-way interaction between contraction, condition, and subject for maximal motor unit firing rates, force, and EMG. Thus, combined contraction responses were different for conditions across subjects. Some conditions (eg, a muscle spasm) resulted in more effective and more frequent responses (increases in unit firing frequency, force, EMG in >50% contractions) than others. Recruitment of new units also occurred in combined contractions. Motoneurons are still responsive to additional afferent inputs from various sources when rate modulation from voluntary drive is limited by SCI. Individuals with SCI may be able to combine inputs to control functional tasks they cannot perform with voluntary drive alone.

  4. 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.

  5. 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.

  6. Topology Change and Tensor Forces for the EoS of Dense Baryonic Matter

    CERN Document Server

    Lee, Hyun Kyu

    2013-01-01

    When skyrmions representing nucleons are put on crystal lattice and compressed to simulate high density, there is a transition above the normal nuclear matter density $n_0$ from a matter consisting of skyrmions with integer baryon charge to a state of half-skyrmions with half-integer baryon charge. We exploit this observation in an effective field theory formalism to access dense baryonic system. We find that the topology change involved implies a changeover from a Fermi liquid structure to a non-Fermi liquid with the chiral condensate in the nucleon "melted off." The $\\sim 80%$ of the nucleon mass that remains, invariant under chiral transformation, points to the origin of the (bulk of) proton mass that is not encoded in the standard mechanism of spontaneously broken chiral symmetry. The topology change engenders a drastic modification of the nuclear tensor forces, thereby nontrivially affecting the EoS, in particular, the symmetry energy, for compact star matter. It brings in stiffening of the EoS needed to...

  7. The role of natural versus forced change in future rapid summer Arctic ice loss

    Science.gov (United States)

    Holland, Marika M.; Bitz, Cecilia M.; Tremblay, L.-Bruno; Bailey, David A.

    Climate model simulations from the Community Climate System Model, version 3 (CCSM3) suggest that Arctic sea ice could undergo rapid September ice retreat in the 21st century. A previous study indicated that this results from a thinning of sea ice to more vulnerable conditions, a "kick" in the form of pulse-like increases in ocean heat transport and positive feedbacks that accelerate the retreat. Here we further examine the factors affecting these events, including the role of natural versus forced change and the possibility of threshold-like behavior in the simulated sea ice cover. We find little indication that a critical sea ice state is reached that then leads to rapid ice loss. Instead, our results suggest that the rapid ice loss events result from anthropogenic change reinforced by growing intrinsic variability. The natural variability in summer ice extent increases in the 21st century because of the thinning ice cover. As the ice thins, large regions can easily melt out, resulting in considerable ice extent variations. The important role of natural variability in the simulated rapid ice loss is such that we find little capability for predicting these events based on a knowledge of prior ice and ocean conditions. This is supported by results from sensitivity simulations initialized several years prior to an event, which exhibit little predictive skill.

  8. Spatial pattern of land use change and its driving force in Jiangsu Province.

    Science.gov (United States)

    Du, Xindong; Jin, Xiaobin; Yang, Xilian; Yang, Xuhong; Zhou, Yinkang

    2014-03-18

    Scientific interpretation of the mechanism of land use change is important for government planning and management activities. This study analyzes the land use change in Jiangsu Province using three land use maps of 2000, 2005 and 2008. The study results show that there was a significant change in land use. The change was mainly characterized by a continuous built-up land expansion primarily at the expense of cropland loss, and the trend became increasingly rapid. There was an obvious regional difference, as most of the cropland loss or built-up land expansion took place in southern Jiangsu, where the rate of built-up land expansion was faster than in central and northern Jiangsu. Meanwhile, the spatial pattern changed remarkably; in general, the number of patches (NumP) showed a declining trend, and the mean patch size (MPS) and patch size standard deviation (PSSD) displayed increase trends. Furthermore, the relative importance of selected driven factors was identified by principal component analysis (PCA) and general linear model (GLM). The results showed that not only the relative importance of a specific driving factor may vary, but the driven factors may as well. The most important driven factor changed from urban population (UP), secondary gross domestic product (SGDP) and gross domestic product (GDP) during 2000-2005 to resident population (RP), population density (POD) and UP during 2005-2008, and the deviance explained (DE) decreased from 91.60% to 81.04%. Policies also had significant impacts on land use change, which can be divided into direct and indirect impacts. Development policies usually had indirect impacts, particularly economic development policies, which promote the economic development to cause land use change, while land management policies had direct impacts. We suggest that the government should think comprehensively and cautiously when proposing a new development strategy or plan.

  9. 47 CFR 76.1603 - Customer service-rate and service changes.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Customer service-rate and service changes. 76... SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1603 Customer service—rate and service changes. (a) A cable franchise authority may enforce the customer service standards set forth in...

  10. 76 FR 73674 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2011-11-29

    ... Bureau of Reclamation Change in Discount Rate for Water Resources Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water... resources planning. The discount rate for Federal water resources planning for fiscal year 2012 is 4 percent...

  11. 78 FR 16706 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2013-03-18

    ... Bureau of Reclamation Change in Discount Rate for Water Resources Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water... resources planning. The discount rate for Federal water resources planning for fiscal year 2013 is 3.75...

  12. 75 FR 8106 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2010-02-23

    ... Bureau of Reclamation Change in Discount Rate for Water Resources Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water... resources planning. The discount rate for Federal water resources planning for fiscal year 2010 is 4.375...

  13. 78 FR 67393 - Change in Discount Rate for Water Resources Planning

    Science.gov (United States)

    2013-11-12

    ... Bureau of Reclamation Change in Discount Rate for Water Resources Planning AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of change. SUMMARY: The Water Resources Planning Act of 1965 and the Water... resources planning. The discount rate for Federal water resources planning for fiscal year 2014 is 3.50...

  14. Explaining Changing Suicide Rates in Norway 1948-2004: The Role of Social Integration

    Science.gov (United States)

    Barstad, Anders

    2008-01-01

    Using Norway 1948-2004 as a case, I test whether changes in variables related to social integration can explain changes in suicide rates. The method is the Box-Jenkins approach to time-series analysis. Different aspects of family integration contribute significantly to the explanation of Norwegian suicide rates in this period. The estimated effect…

  15. Rate of Change: AP Calculus Students' Understandings and Misconceptions after Completing Different Curricular Paths

    Science.gov (United States)

    Teuscher, Dawn; Reys, Robert E.

    2012-01-01

    This study examined Advanced Placement Calculus students' mathematical understanding of rate of change, after studying four years of college preparatory (integrated or single-subject) mathematics. Students completed the Precalculus Concept Assessment (PCA) and two open-ended tasks with questions about rates of change. After adjusting for prior…

  16. Cortical porosity exhibits accelerated rate of change in peri- compared with post-menopausal women.

    Science.gov (United States)

    Burt, L A; Bhatla, J L; Hanley, D A; Boyd, S K

    2017-01-10

    The rate of change in bone density was not different between peri- and post-menopausal women. Differences in rate of change were observed in bone microarchitecture, specifically cortical porosity (Ct.Po), where peri-menopausal women increased +9% per year compared with the +6% per year for post-menopausal women.

  17. Rate of Change: AP Calculus Students' Understandings and Misconceptions after Completing Different Curricular Paths

    Science.gov (United States)

    Teuscher, Dawn; Reys, Robert E.

    2012-01-01

    This study examined Advanced Placement Calculus students' mathematical understanding of rate of change, after studying four years of college preparatory (integrated or single-subject) mathematics. Students completed the Precalculus Concept Assessment (PCA) and two open-ended tasks with questions about rates of change. After adjusting for prior…

  18. Explaining Changing Suicide Rates in Norway 1948-2004: The Role of Social Integration

    Science.gov (United States)

    Barstad, Anders

    2008-01-01

    Using Norway 1948-2004 as a case, I test whether changes in variables related to social integration can explain changes in suicide rates. The method is the Box-Jenkins approach to time-series analysis. Different aspects of family integration contribute significantly to the explanation of Norwegian suicide rates in this period. The estimated effect…

  19. 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.

  20. Estimation of Uncertainty in Tracer Gas Measurement of Air Change Rates

    Directory of Open Access Journals (Sweden)

    Atsushi Iizuka

    2010-12-01

    Full Text Available Simple and economical measurement of air change rates can be achieved with a passive-type tracer gas doser and sampler. However, this is made more complex by the fact many buildings are not a single fully mixed zone. This means many measurements are required to obtain information on ventilation conditions. In this study, we evaluated the uncertainty of tracer gas measurement of air change rate in n completely mixed zones. A single measurement with one tracer gas could be used to simply estimate the air change rate when n = 2. Accurate air change rates could not be obtained for n ≥ 2 due to a lack of information. However, the proposed method can be used to estimate an air change rate with an accuracy of

  1. Changes in adjustment force, speed, and direction factors in chiropractic students after 10 weeks undergoing standard technique training.

    Science.gov (United States)

    Owens, Edward F; Russell, Brent S; Hosek, Ronald S; Sullivan, Stephanie G B; Dever, Lydia L; Mullin, Linda

    2017-08-02

    To assess the force profiles of high-velocity low-amplitude thrusts delivered to a mannequin on a force platform by novice students given only verbal instructions. Student volunteers untrained in adjusting delivered a series of adjustments to a mannequin on a force platform. Participants performed 3 light, 3 normal, and 3 heavy thrusts on 5 listings specifying contact point, hand, and direction. Force profiles were analyzed for speed and amplitude, consistency, and force discrimination. Two recording sessions occurred 10 weeks apart. Sixteen participants (11 females, 5 male) completed the study. Peak forces ranged from 880 to 202 N for heavy thrusts and 322- to 66 N for light thrusts. Thrust rate was from 8.1 to 1.8 Newtons per millisecond. Average coefficients of variability (CV = STD/mean) at each load level (initial/final) were heavy: 17%/15%; normal: 16%/15%; and light: 20%/20%, with 0 as ideal. A force ratio measured students' abilities to distinguish thrust magnitude. The heavy/normal ratio (initial/final) was 1.35/1.39, and the light/normal ratio was 0.70/0.67. At this point, without force feedback being used in the classroom, novice students can produce thrusts that look like those of their teachers and of experienced practitioners, but they may not produce similar speed and force values. They are consistent within and between sessions and can discriminate between light and heavy loads. A natural next step in our educational research will be to measure adjustment factors on more experienced cohorts of students with and without the presence of force-feedback training apparatus.

  2. The influence of national leader change on corruption and sovereign rating

    OpenAIRE

    Kuei-Yuan Wang; Sheng-Min Tu

    2014-01-01

    Corruption is a critical social and ethical problem that can impede the economic growth of a country or even ruin a country. In addition, the importance of the sovereign rating of a country cannot be underestimated. A change in the sovereign rating of a country can affect its borrowing capacity. Using members of the United Nations from 1995 to 2012 as the research sample, this study investigated the influence of national leader change on corruption and sovereign rating by analyzing one year a...

  3. 75 FR 47650 - International Product Change-Global Expedited Package Services-Non-Published Rates

    Science.gov (United States)

    2010-08-06

    ... Product Change--Global Expedited Package Services-- Non-Published Rates AGENCY: Postal Service\\TM\\ ACTION... Service to add Global Expedited Package Contracts--Non-Published Rates to the Competitive Products List... Commission to add Global Expedited Package Services Contracts--Non-Published Rates to the Competitive...

  4. 76 FR 2930 - International Product Change-Global Expedited Package Services-Non- Published Rates

    Science.gov (United States)

    2011-01-18

    ... Product Change--Global Expedited Package Services-- Non- Published Rates AGENCY: Postal Service\\TM... Commission to add Global Expedited Package Services-- Non-Published Rates 2 to the Competitive Products List... Service to add Global Expedited Package Services--Non-Published Rates, to the Competitive Products List...

  5. Examining the reaction of monetary policy to exchange rate changes: A nonlinear ARDL approach

    Science.gov (United States)

    Manogaran, Lavaneesvari; Sek, Siok Kun

    2017-04-01

    Previous studies showed the exchange rate changes can have significant impacts on macroeconomic performance. Over fluctuation of exchange rate may lead to economic instability. Hence, monetary policy rule tends to react to exchange rate changes. Especially, in emerging economies where the policy-maker tends to limit the exchange rate movement through interventions. In this study, we seek to investigate how the monetary policy rule reacts to exchange rate changes. The nonlinear autoregressive distributed lag (NARDL) model is applied to capture the asymmetric effect of exchange rate changes on monetary policy reaction function (interest rate). We focus the study in ASEAN5 countries (Indonesia, Malaysia, Philippines, Thailand and Singapore). The results indicated the existence of asymmetric effect of exchange rates changes on the monetary reaction function for all ASEAN5 countries in the long-run. Where, in majority of the cases the monetary policy is reacting to the appreciation and depreciation of exchange rate by raising the policy rate. This affirms the intervention of policymakers with the `fear of floating' behavior.

  6. Characterizing potentially induced earthquake rate changes in the Brawley Seismic Zone, southern California

    Science.gov (United States)

    Llenos, Andrea L.; Michael, Andrew J.

    2016-01-01

    The Brawley seismic zone (BSZ), in the Salton trough of southern California, has a history of earthquake swarms and geothermal energy exploitation. Some earthquake rate changes may have been induced by fluid extraction and injection activity at local geothermal fields, particularly at the North Brawley Geothermal Field (NBGF) and at the Salton Sea Geothermal Field (SSGF). We explore this issue by examining earthquake rate changes and interevent distance distributions in these fields. In Oklahoma and Arkansas, where considerable wastewater injection occurs, increases in background seismicity rate and aftershock productivity and decreases in interevent distance were indicative of fluid‐injection‐induced seismicity. Here, we test if similar changes occur that may be associated with fluid injection and extraction in geothermal areas. We use stochastic epidemic‐type aftershock sequence models to detect changes in the underlying seismogenic processes, shown by statistically significant changes in the model parameters. The most robust model changes in the SSGF roughly occur when large changes in net fluid production occur, but a similar correlation is not seen in the NBGF. Also, although both background seismicity rate and aftershock productivity increased for fluid‐injection‐induced earthquake rate changes in Oklahoma and Arkansas, the background rate increases significantly in the BSZ only, roughly corresponding with net fluid production rate increases. Moreover, in both fields the interevent spacing does not change significantly during active energy projects. This suggests that, although geothermal field activities in a tectonically active region may not significantly change the physics of earthquake interactions, earthquake rates may still be driven by fluid injection or extraction rates, particularly in the SSGF.

  7. Changes in the skill structure of the labour force. An empirical application to the Spanisch case

    OpenAIRE

    Moreno Galbis, Eva

    2002-01-01

    Over the past two decades the Spanisch economy, as well as many other economies, has known a process of skill upgrading in its labour force. Although many previous studies on this phenomena took as reference non production workers, the present study focus on high skilled labour force. Most of the variation in this qualified labour force has been within industries which points to internal reorganization of firms as the origin of this shift. To analyze the impact of physical and technological c...

  8. Changes in the skill structure of the labour force. An empirical application to the Spanish case

    OpenAIRE

    Eva, MORENO GALBIS

    2002-01-01

    Over the past two decades the Spanish economy, as well as many other economies, has known a process of skill upgrading in its labour force. Although many previous studies on this phenomena took as reference non production workers, the present study focus on high skilled labour force. Most of the variation in this qualified labour force has been within industries which points to internal reorganization of firms as the origin of this shift. To analyze the impact of physical and technological ca...

  9. Transformational Leadership and the New Zealand Defence Force: Supporting Effective Organizational Change

    Science.gov (United States)

    2016-06-10

    Force, 2012), 14. 20 This assertion was supported by the Controller and Auditor - General in their report on the civilianization process. 21 New Zealand...Defence Force, Annual Report , 15. 22 Controller and Auditor - General , The Civilianisation Process, 15. 23 New Zealand Defence Force, NZDF Ongoing...Army Command and General Staff College ATTN: ATZL-SWD-GD Fort Leavenworth, KS 66027-2301 8. PERFORMING ORG REPORT NUMBER 9. SPONSORING

  10. Tracking Traction Force Changes of Single Cells on the Liquid Crystal Surface

    OpenAIRE

    Chin Fhong Soon; Kian Sek Tee; Mansour Youseffi; Denyer, Morgan C. T.

    2015-01-01

    Cell migration is a key contributor to wound repair. This study presents findings indicating that the liquid crystal based cell traction force transducer (LCTFT) system can be used in conjunction with a bespoke cell traction force mapping (CTFM) software to monitor cell/surface traction forces from quiescent state in real time. In this study, time-lapse photo microscopy allowed cell induced deformations in liquid crystal coated substrates to be monitored and analyzed. The results indicated th...

  11. Satellite observed changes in the Northern Hemisphere snow cover phenology and the associated radiative forcing and feedback between 1982 and 2013

    Science.gov (United States)

    Chen, Xiaona; Liang, Shunlin; Cao, Yunfeng

    2016-08-01

    Quantifying continental-scale changes in snow cover phenology (SCP) and evaluating their associated radiative forcing and feedback is essential for meteorological, hydrological, ecological, and societal purposes. However, the current SCP research is inadequate because few published studies have explored the long-term changes in SCP, as well as their associated radiative forcing and feedback in the context of global warming. Based on satellite-observed snow cover extent (SCE) and land surface albedo datasets, and using a radiative kernel modeling method, this study quantified changes in SCP and the associated radiative forcing and feedback over the Northern Hemisphere (NH) snow-covered landmass from 1982 to 2013. The monthly SCE anomaly over the NH displayed a significant decreasing trend from May to August (-0.89 × 106 km2 decade-1), while an increasing trend from November to February (0.65 × 106 km2 decade-1) over that period. The changes in SCE resulted in corresponding anomalies in SCP. The snow onset date (D o) moved forward slightly, but the snow end date (D e) advanced significantly at the rate of 1.91 days decade-1, with a 73% contribution from decreased SCE in Eurasia (EU). The anomalies in D e resulted in a weakened snow radiative forcing of 0.12 (±0.003) W m-2 and feedback of 0.21 (±0.005) W m-2 K-1, in melting season, over the NH, from 1982 to 2013. Compared with the SCP changes in EU, the SCP anomalies in North America were relatively stable because of the clearly contrasting D e anomalies between the mid- and high latitudes in this region.

  12. Weak hydrological sensitivity to temperature change over land, independent of climate forcing

    Science.gov (United States)

    Samset, Bjorn H.

    2017-04-01

    As the global surface temperature changes, so will patterns and rates of precipitation. Theoretically, these changes can be understood in terms of changes to the energy balance of the atmosphere, caused by introducing drivers of climate change such as greenhouse gases, aerosols and altered insolation. Climate models, however, disagree strongly in their prediction of precipitation changes, both for historical and future emission pathways, and per degree of surface warming in idealized experiments. The latter value, often termed the apparent hydrological sensitivity, has also been found to differ substantially between climate drivers. Here, we present the global and regional hydrological sensitivity (HS) to surface temperature changes, for perturbations to CO2, CH4, sulfate and black carbon concentrations, and solar irradiance. Based on results from 10 climate models participating in the Precipitation Driver and Response Model Intercomparison Project (PDRMIP), we show how modeled global mean precipitation increases by 2-3 % per kelvin of global mean surface warming, independent of driver, when the effects of rapid adjustments are removed. Previously reported differences in response between drivers are therefore mainly ascribable to rapid atmospheric adjustment processes. All models show a sharp contrast in behavior over land and over ocean, with a strong surface temperature driven (slow) ocean HS of 3-5 %/K, while the slow land HS is only 0-2 %/K. Separating the response into convective and large-scale cloud processes, we find larger inter-model differences, in particular over land regions. Large-scale precipitation changes are most relevant at high latitudes, while the equatorial HS is dominated by convective precipitation changes. Black carbon stands out as the driver with the largest inter-model slow HS variability, and also the strongest contrast between a weak land and strong sea response. Convective precipitation in the Arctic and large scale precipitation

  13. 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-...

  14. Left ventricular dimensions and systolic function during spontaneous heart rate changes: an echocardiographic study.

    Science.gov (United States)

    Bett, J H; Dryburgh, L

    1981-06-01

    We examined the relationships between spontaneous heart rate (or conversely cycle length) changes and left ventricular diastolic dimensions and indices of systolic function in twenty-three subjects. In most there was clearly an inverse relationship between rate and these indices and nearly always a positive correlation between performance and end-diastolic dimension. Previously described relationship between heart rate and mean velocity of circumferential fiber shortening are applicable only when the heart rate is constant.

  15. Resonance of about-weekly human heart rate rhythm with solar activity change.

    Science.gov (United States)

    Cornelissen, G; Halberg, F; Wendt, H W; Bingham, C; Sothern, R B; Haus, E; Kleitman, E; Kleitman, N; Revilla, M A; Revilla, M; Breus, T K; Pimenov, K; Grigoriev, A E; Mitish, M D; Yatsyk, G V; Syutkina, E V

    1996-12-01

    In several human adults, certain solar activity rhythms may influence an about 7-day rhythm in heart rate. When no about-weekly feature was found in the rate of change in sunspot area, a measure of solar activity, the double amplitude of a circadian heart rate rhythm, approximated by the fit of a 7-day cosine curve, was lower, as was heart rate corresponds to about-weekly features in solar activity and/or relates to a sunspot cycle.

  16. Atomic force microscopy evidence for conformational changes of fibronectin adsorbed on unmodified and sulfonated polystyrene surfaces.

    Science.gov (United States)

    Kowalczyńska, Hanna M; Kołos, Robert; Nowak-Wyrzykowska, Małgorzata; Dobkowski, Jacek; Elbaum, Danek; Szczepankiewicz, Andrzej; Kamiński, Jarosław

    2009-12-15

    The effect of polystyrene surface polarity on the conformation of adsorbed fibronectin (FN) has been studied with atomic force microscopy. We demonstrated that bare sulfonated and nonsulfonated polystyrene surfaces featured similar topographies. After the FN adsorption, direct comparison of both types of substrata revealed drastically different topographies, roughness values, and also cell-adhesive properties. This was interpreted in terms of FN conformational changes induced by the surface polarity. At high-solute FN concentrations the multilayer FN adsorption took place resulting, for the sulfonated substratum, in an increase of surface roughness, whereas for the nonsulfonated one the roughness was approximately stable. Conversely, the FN conformation characteristic for the first saturative layer tended to be conserved in the consecutive layers, as evidenced by height histograms. The height of individual FN molecules indicated, consonantly with the derived thickness of the adsorbed protein layer (the latter value being 1.4 nm and 0.6 nm, respectively, for an unmodified and sulfonated polystyrene surface), that molecules are flattened on polar surfaces and more compact on nonsulfonated ones. It was also demonstrated that the FN adsorption and conformation on polymeric substrata, and hence the resultant cell-adhesive properties, depended on the chemistry of the original surface rather than on its topography. Our results also demonstrated the ability of surface polarity to influence the protein conformation and its associated biological activity.

  17. Changes in spatial memory and BDNF expression to simultaneous dietary restriction and forced exercise.

    Science.gov (United States)

    Khabour, Omar F; Alzoubi, Karem H; Alomari, Mahmoud A; Alzubi, Mohammad A

    2013-01-01

    Previous literature suggests that learning and memory formation can be influenced by diet and exercise. In the current study, we investigated the combined effects of forced swimming exercise (FSE) and every other day fasting (EODF) on spatial memory formation and on the levels of brain-derived neurotrophic factor (BDNF) in the hippocampus of Wistar male rats. The radial arm water maze (RAWM) paradigm was used to assess changes in learning and memory formation, whereas ELISA assay was used to measure BDNF protein levels. The FSE and/or EODF were simultaneously instituted for 6 weeks. Results show that FSE improved learning, short-term as well as long-term memory formation, and significantly increased BDNF protein in the hippocampus (peffect on either spatial learning and memory formation or the levels of hippocamapal BDNF protein (p>0.05). In addition, EODF did not modulate beneficial effect of swimming exercise on cognitive function (p>0.05). Thus exercise enhanced, while EODF did not affect spatial learning and memory formation.

  18. The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) contribution to CMIP6: investigation of sea-level and ocean climate change in response to CO2 forcing

    Science.gov (United States)

    Gregory, Jonathan M.; Bouttes, Nathaelle; Griffies, Stephen M.; Haak, Helmuth; Hurlin, William J.; Jungclaus, Johann; Kelley, Maxwell; Lee, Warren G.; Marshall, John; Romanou, Anastasia; Saenko, Oleg A.; Stammer, Detlef; Winton, Michael

    2016-11-01

    The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) aims to investigate the spread in simulations of sea-level and ocean climate change in response to CO2 forcing by atmosphere-ocean general circulation models (AOGCMs). It is particularly motivated by the uncertainties in projections of ocean heat uptake, global-mean sea-level rise due to thermal expansion and the geographical patterns of sea-level change due to ocean density and circulation change. FAFMIP has three tier-1 experiments, in which prescribed surface flux perturbations of momentum, heat and freshwater respectively are applied to the ocean in separate AOGCM simulations. All other conditions are as in the pre-industrial control. The prescribed fields are typical of pattern and magnitude of changes in these fluxes projected by AOGCMs for doubled CO2 concentration. Five groups have tested the experimental design with existing AOGCMs. Their results show diversity in the pattern and magnitude of changes, with some common qualitative features. Heat and water flux perturbation cause the dipole in sea-level change in the North Atlantic, while momentum and heat flux perturbation cause the gradient across the Antarctic Circumpolar Current. The Atlantic meridional overturning circulation (AMOC) declines in response to the heat flux perturbation, and there is a strong positive feedback on this effect due to the consequent cooling of sea-surface temperature in the North Atlantic, which enhances the local heat input to the ocean. The momentum and water flux perturbations do not substantially affect the AMOC. Heat is taken up largely as a passive tracer in the Southern Ocean, which is the region of greatest heat input, while the weakening of the AMOC causes redistribution of heat towards lower latitudes. Future analysis of these and other phenomena with the wider range of CMIP6 FAFMIP AOGCMs will benefit from new diagnostics of temperature and salinity tendencies, which will enable investigation of the

  19. Low-Stress Upper Plate Near Subduction Zones and Implications for Temporal Changes in Loading Forces

    Science.gov (United States)

    Wang, K.; Hu, Y.; Yoshida, K.

    2016-12-01

    Subduction megathrusts are weak, often with effective friction coefficients as low as 0.03. Consequently, differential stress (S1 - S3) in the nearby upper plate is low. Compression due to plate coupling and tension due to gravity are in a subtle balance that can be tipped by small perturbations. For example, the 2011 M=9 Tohoku-oki earthquake, which has a rupture-zone-average stress drop of only a few MPa, switched offshore margin-normal stress from compression to tension and affected seismicity pattern and stress directions of various parts of the land area. The low differential stress is also reflected in spatial variations of stresses, such as with changes in topography. In the Andes, crustal earthquake focal mechanisms change from thrust-faulting in low-elevation areas to normal-faulting in high-elevation areas. Given the lack of evidence for a pervasively weak crust, the low differential stress may indicate that in general the crust near subduction zones is not critically stressed. If so, crustal earthquakes do not represent pervasive failure but only local failure due to stress, material, and fluid pressure heterogeneity. If distributed permanent deformation that creates topography is not the norm, it either happens in brief episodes or took place in the past. The outer wedge may enter a compressively or extensionally critical state due to coseismic strengthening or weakening, respectively, of the shallow megathrust in largest interplate earthquakes. Temporal changes in loading forces must occur also at much larger temporal and spatial scales in response to changes in the nature of the subducting plate and other tectonic conditions. We propose that submarine wedges and high topography in the upper plate attain their geometry in geologically brief episodes of high differential stress. They normally stay in a low-stress stable state, but their geometry often reflects high-stress episodes of critical states in the past. In other words, rocks have a sustained

  20. Changes in hospitalization rate and mortality after acute myocardial infarction in Denmark after diagnostic criteria and methods changed

    DEFF Research Database (Denmark)

    Abildstrøm, Steen Zabell; Rasmussen, Søren; Madsen, Mette

    2004-01-01

    AIMS: To analyse the effect of the change in diagnostic criteria for acute myocardial infarction (AMI) and the use of troponin as a diagnostic marker on the hospitalization rate and mortality of hospitalized AMI patients from 1994 to 2001. METHODS AND RESULTS: Patients (> or =30 years) admitted.......9%) for men and from 1648 to 2020 per million inhabitants (22.6%) for women. Troponin use was associated with a significant 14% increase in hospitalization rate in this period [rate ratio 1.14, 95% confidence interval (CI) 1.11-1.18]. The effect of troponin was greatest among patients 70 years and older (rate...

  1. Global Climate Forcing from Albedo Change Caused by Large-scale Deforestation and Reforestation: Quantification and Attribution of Geographic Variation

    Science.gov (United States)

    Jiao, Tong; Williams, Christopher A.; Ghimire, Bardan; Masek, Jeffrey; Gao, Feng; Schaaf, Crystal

    2017-01-01

    Large-scale deforestation and reforestation have contributed substantially to historical and contemporary global climate change in part through albedo-induced radiative forcing, with meaningful implications for forest management aiming to mitigate climate change. Associated warming or cooling varies widely across the globe due to a range of factors including forest type, snow cover, and insolation, but resulting geographic variation remain spoorly described and has been largely based on model assessments. This study provides an observation-based approach to quantify local and global radiative forcings from large-scale deforestation and reforestation and further examines mechanisms that result in the spatial heterogeneity of radiative forcing. We incorporate a new spatially and temporally explicit land cover-specific albedo product derived from Moderate Resolution Imaging Spectroradiometer with a historical land use data set (Land Use Harmonization product). Spatial variation in radiative forcing was attributed to four mechanisms, including the change in snow-covered albedo, change in snow-free albedo, snow cover fraction, and incoming solar radiation. We find an albedo-only radiative forcing (RF) of -0.819 W m(exp -2) if year 2000 forests were completely deforested and converted to croplands. Albedo RF from global reforestation of present-day croplands to recover year 1700 forests is estimated to be 0.161 W m)exp -2). Snow-cover fraction is identified as the primary factor in determining the spatial variation of radiative forcing in winter, while the magnitude of the change in snow-free albedo is the primary factor determining variations in summertime RF. Findings reinforce the notion that, for conifers at the snowier high latitudes, albedo RF diminishes the warming from forest loss and the cooling from forest gain more so than for other forest types, latitudes, and climate settings.

  2. Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat.

    Science.gov (United States)

    Olesen, Annesofie T; Jensen, Bente R; Uhlendorf, Toni L; Cohen, Randy W; Baan, Guus C; Maas, Huub

    2014-11-01

    The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO), and plantaris (PL) were assessed in anesthetized spastic and normally developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO, and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA), was investigated. Active length-force curves of spastic GA and PL were narrower with a reduced maximal active force. In contrast, active length-force characteristics of spastic SO were similar to those of controls. In reference position (90° ankle and knee angle), higher resistance to ankle dorsiflexion and increased passive stiffness was found for the spastic calf muscle group. At optimum length, passive stiffness and passive force of spastic GA were decreased, whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO and PL. However, the extent of this interaction was not different in spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes observed for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate that altered mechanics in spastic rats cannot be attributed to differences in mechanical interaction, but originate from individual muscular structures. Copyright © 2014 the American Physiological Society.

  3. 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

  4. How sensitive are nanosecond molecular dynamics simulations of proteins to changes in the force field?

    NARCIS (Netherlands)

    Villa, Alessandra; Fan, Hao; Wassenaar, Tsjerk; Mark, Alan E.

    2007-01-01

    The sensitivity of molecular dynamics simulations to variations in the force field has been examined in relation to a set of 36 structures corresponding to 31 proteins simulated by using different versions of the GROMOS force field. The three parameter sets used (43a1, 53a5, and 53a6) differ signifi

  5. Soft tissue balance changes depending on joint distraction force in total knee arthroplasty.

    Science.gov (United States)

    Nagai, Kanto; Muratsu, Hirotsugu; Matsumoto, Tomoyuki; Miya, Hidetoshi; Kuroda, Ryosuke; Kurosaka, Masahiro

    2014-03-01

    The influence of joint distraction force on intraoperative soft tissue balance was evaluated using Offset Repo-Tensor® for 78 knees that underwent primary posterior-stabilized total knee arthroplasty. The joint center gap and varus ligament balance were measured between osteotomized surfaces using 20, 40 and 60 lbs of joint distraction force. These values were significantly increased at extension and flexion as the distraction force increased. Furthermore, lateral compartment stiffness was significantly lower than medial compartment stiffness. Thus, larger joint distraction forces led to larger varus ligament balance and joint center gap, because of the difference in soft tissue stiffness between lateral and medial compartments. These findings indicate the importance of the strength of joint distraction force in the assessment of soft tissue balance, especially when using gap-balancing technique.

  6. Farming and forestry land use changes in China and their driving forces from 1900 to 1980

    Institute of Scientific and Technical Information of China (English)

    GE; Quansheng; DAI; Junhu

    2005-01-01

    A variety of agricultural and forestry land use materials, especially those in the first half of 20th century, were collected. According to land use change in this period, the whole country is demarcated into seven regions, Northeast China, North China, Northwest and Loess Plateau, Southeast and Coastal Region, Southwest China, Qinghai-Tibetan Plateau, Inner Mongolia and Xinjiang, in proper order by using Cluster Analysis. The farming and forestry land use change in these regions were analyzed. The results show that the total cultivated land areas increased in this period, especially in the 1950s and 1960s the cultivated land area increased more significantly, but differed in different regions, and the most rapid increasing rate was 2.63 percent a year. On the other hand, the forestry land area was increasing in most parts of this period, especially after 1949. But in most regions, the decrease of forestry land area at the end of 1970s is also very obvious. It is regarded that the population increase, food production, natural disasters and some related government policies were among the main driving factors for farming and forestry land use change.

  7. Participant attributions for global change ratings in unexplained chronic fatigue and chronic fatigue syndrome.

    Science.gov (United States)

    Friedberg, Fred; Coronel, Janna; Seva, Viktoria; Adamowicz, Jenna L; Napoli, Anthony

    2016-05-01

    The purpose of this mixed methods study was to identify participants' attributions for their global impression of change ratings in a behavioral intervention for unexplained chronic fatigue and chronic fatigue syndrome. At 3-month follow-up, participants (N = 67) were asked "Why do you think you are (improved, unchanged, worse)?" Improved patients pointed to specific behavioral changes, unchanged patients referred to a lack of change in lifestyle, and worsened patients invoked stress and/or specific life events. Identifying patient perceptions of behaviors associated with patient global impression of change-rated improvement and non-improvement may assist in developing more effective management strategies in clinical care.

  8. Accelerated greenhouse gases versus slow insolation forcing induced climate changes in southern South America since the Mid-Holocene

    Science.gov (United States)

    Berman, Ana Laura; Silvestri, Gabriel E.; Rojas, Maisa; Tonello, Marcela S.

    2017-01-01

    This paper is a pioneering analysis of past climates in southern South America combining multiproxy reconstructions and the state-of-the-art CMIP5/PMIP3 paleoclimatic models to investigate the time evolution of regional climatic conditions from the Mid-Holocene (MH) to the present. This analysis allows a comparison between the impact of the long term climate variations associated with insolation changes and the more recent effects of anthropogenic forcing on the region. The PMIP3 multimodel experiments suggest that changes in precipitation over almost all southern South America between MH and pre-industrial (PI) times due to insolation variations are significantly larger than those between PI and the present, which are due to changes in greenhouse gas concentrations. Anthropogenic forcing has been particularly intense over western Patagonia inducing reduction of precipitation in summer, autumn and winter as a consequence of progressively weaker westerly winds over the region, which have moved further poleward, between ca. 35-55°S and have become stronger south of about 50°S. Orbital variations between the MH to the PI period increased insolation over southern South America during summer and autumn inducing warmer conditions in the PI, accentuated by the effect of anthropogenic forcing during the last century. On the other hand, changes in orbital parameters from the MH to the PI period reduced insolation during winter and spring inducing colder conditions, which have been reversed by the anthropogenic forcing.

  9. Analysis of Muscle Force-Velocity Parameter Changes in Elderly Women Resulting from Physical Activity--In Continuous Examinations

    Science.gov (United States)

    Skrzek, Anna; Stefanska, Malgorzata

    2012-01-01

    The aim of the paper was to evaluate changes in muscle force-velocity parameters (F-v) in elderly women subjected to physical exercise. The examinations encompassed 20 women, aged 62-71, who were students at the University of the Third Age in Wroclaw. The evaluation of flexors and extensors of the knee joint, as well as flexors and extensors of…

  10. The Challenge: Latinos in a Changing California. The Report of the University of California SCR 43 Task Force.

    Science.gov (United States)

    California Univ., Riverside. Consortium on Mexico and the United States.

    This document presents a report from a task force composed of scholars, professionals, and community leaders to the State of California and the University of California (UC) addressing issues affecting Latinos in California. The following major recommendations are discussed: (1) continuing research must be undertaken concerning dynamic changes and…

  11. Land use and land cover change and its driving forces in Maqu County, China in the past 25 years

    Institute of Scientific and Technical Information of China (English)

    JunFeng Lu; ZhiBao Dong; GuangYin Hu; WenJin Li; WanYin Luo; MingLiang Tan

    2016-01-01

    Maqu County is located in the northeast Qinghai-Tibetan Plateau, and it is the main watershed for the Yellow River. The ecosystem there is extremely vulnerable and sensitive to climate change and human activities, which have caused significant deterioration of the eco-environment in this region. In order to restore the ecological environment, a government project to restore the grazing areas to grassland was implemented in Maqu County in early 2004. This study evaluates the effects of that restoration project on land use and land cover change (LUCC), and explores the driving forces of LUCC in Maqu County. In the study we used Landsat images obtained in 1989, 2004, 2009, and 2014 to establish databases of land use and land cover. Then we derived LUCC information by overlaying these layers using GIS software. Finally, we analyzed the main forces responsible for LUCC. The results showed that forests, high-coverage grasslands, and marshes experienced the most signif-icant decreases during 1989–2004, by 882.8 ha, 35,250.4 ha, and 2,753.4 ha, respectively. However, moderate- and low-coverage grasslands and sand lands showed the opposite trend, increasing by 12,529.7 ha, 25,491.0 ha, and 577.5 ha, respectively. LUCC in 2004–2009 showed that ecological degradation slowed compared with 1989−2004. During 2009–2014, high- and moderate-coverage grasslands increased obviously, but low-coverage grasslands, marshes, unused lands, sand lands, and water areas showed the opposite trend. These results suggested that the degradation of the eco-environment was obvious before 2009, showing a decrease in the forests, grasslands, and water areas, and an increase in unused lands. The ecological degradation was reversed after 2009, as was mainly evidenced by increases in high-and mod-erate-coverage grasslands, and the shrinkage rate of marshes decreased obviously. These results showed that the project of restoring grazing lands to grassland had a positive effect on the LUCC. Other

  12. Breton Island Transects with Shoreline Change Rates (Pre-1950s) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Pre-1950s) (Geographic, NAD83) consists of vector transect data that were derived from the Digital...

  13. Breton Island, Louisiana Transects with Shoreline Change Rates (1869 - 2014) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (1869 - 2014) (Geographic, NAD83) consists of vector transect data that were derived from the Digital...

  14. Breton Island Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83) consists of vector transect data that were derived...

  15. Breton Island, Louisiana Transects with Shoreline Change Rates (Post Hurricane Katrina) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Post Hurricane Katrina) (Geographic, NAD83) consists of vector transect data that was derived from...

  16. Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (Geographic, NAD83) consists of vector transect data that were derived from the Digital...

  17. Breton Island, Louisiana Transects with Shoreline Change Rates (1869 - 2014) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (1869 - 2014) (Geographic, NAD83) consists of vector transect data that were derived from the Digital...

  18. Breton Island Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Pre/Post Hurricane Katrina) (Geographic, NAD83) consists of vector transect data that were derived...

  19. Breton Island Transects with Shoreline Change Rates (Pre-1950s) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Pre-1950s) (Geographic, NAD83) consists of vector transect data that were derived from the Digital...

  20. Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Breton Island, Louisiana Transects with Shoreline Change Rates (Post-1950s) (Geographic, NAD83) consists of vector transect data that were derived from the Digital...