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Sample records for affect spontaneous locomotion

  1. Do altered energy metabolism or spontaneous locomotion 'mediate' decelerated senescence?

    PubMed

    Arum, Oge; Dawson, John Alexander; Smith, Daniel Larry; Kopchick, John J; Allison, David B; Bartke, Andrzej

    2015-06-01

    That one or multiple measures of metabolic rate may be robustly associated with, or possibly even causative of, the progression of aging-resultant phenotypes such as lifespan is a long-standing, well-known mechanistic hypothesis. To broach this hypothesis, we assessed metabolic function and spontaneous locomotion in two genetic and one dietary mouse models for retarded aging, and subjected the data to mediation analyses to determine whether any metabolic or locomotor trait could be identified as a mediator of the effect of any of the interventions on senescence. We do not test the hypothesis of causality (which would require some experiments), but instead test whether the correlation structure of certain variables is consistent with one possible pathway model in which a proposed mediating variable has a causal role. Results for metabolic measures, including oxygen consumption and respiratory quotient, failed to support this hypothesis; similar negative results were obtained for three behavioral motion metrics. Therefore, our mediation analyses did not find support that any of these correlates of decelerated senescence was a substantial mediator of the effect of either of these genetic alterations (with or without caloric restriction) on longevity. Further studies are needed to relate the examined phenotypic characteristics to mechanisms of aging and control of longevity. PMID:25720347

  2. Effects of Spontaneous Locomotion on the Cricket's Walking Response to a Wind Stimulus

    NASA Astrophysics Data System (ADS)

    Gras, Heribert; Bartels, Anke

    Tethered walking crickets often respond to single wind puffs (50ms duration) directed from 45° left or right to the abdominal cerci with a short running bout of about 300ms, followed by normal locomotion. To test for an effect of the current behavioral state on the running response, we applied wind stimuli when the insect attained a predefined translatorial and/or rotatorial velocity during spontaneous walking. The latency, duration, and velocity profile of the running bout always proved to be constant, representing a reflexlike all-or-nothing reaction, while the probability of this response was low after even brief standing and increased with the forward speed of spontaneous walking at the moment of stimulation. In contrast, the current rotatorial speed did not affect the stimulus response.

  3. Locomotion in Stroke Subjects: Interactions between Unaffected and Affected Sides

    ERIC Educational Resources Information Center

    Kloter, Evelyne; Wirz, Markus; Dietz, Volker

    2011-01-01

    The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm…

  4. Methods to Characterize Spontaneous and Startle-induced Locomotion in a Rotenone-induced Parkinson's Disease Model of Drosophila

    PubMed Central

    Liao, Jennifer; Morin, Laura W.; Ahmad, S. Tariq

    2014-01-01

    Parkinson’s disease is a neurodegenerative disorder that results from the degeneration of dopaminergic neurons in the central nervous system, primarily in the substantia nigra. The disease causes motor deficiencies, which present as rigidity, tremors and dementia in humans. Rotenone is an insecticide that causes oxidative damage by inhibiting the function of the electron transport chain in mitochondria. It is also used to model Parkinson’s disease in the Drosophila. Flies have an inherent negative geotactic response, which compels them to climb upwards upon being startled. It has been established that rotenone causes early mortality and locomotion defects that disrupt the flies’ ability to climb after they have been tapped downwards. However, the effect of rotenone on spontaneous movement is not well documented. This study outlines two sensitive, reproducible, and high throughput assays to characterize rotenone-induced deficiencies in short-term startle-induced locomotion and long-term spontaneous locomotion in Drosophila. These assays can be conveniently adapted to characterize other Drosophila models of locomotion defects and efficacy of therapeutic agents. PMID:25178101

  5. Do altered energy metabolism or spontaneous locomotion ‘mediate’ decelerated senescence?

    PubMed Central

    Arum, Oge; Dawson, John Alexander; Smith, Daniel Larry; Kopchick, John J; Allison, David B; Bartke, Andrzej

    2015-01-01

    That one or multiple measures of metabolic rate may be robustly associated with, or possibly even causative of, the progression of aging-resultant phenotypes such as lifespan is a long-standing, well-known mechanistic hypothesis. To broach this hypothesis, we assessed metabolic function and spontaneous locomotion in two genetic and one dietary mouse models for retarded aging, and subjected the data to mediation analyses to determine whether any metabolic or locomotor trait could be identified as a mediator of the effect of any of the interventions on senescence. We do not test the hypothesis of causality (which would require some experiments), but instead test whether the correlation structure of certain variables is consistent with one possible pathway model in which a proposed mediating variable has a causal role. Results for metabolic measures, including oxygen consumption and respiratory quotient, failed to support this hypothesis; similar negative results were obtained for three behavioral motion metrics. Therefore, our mediation analyses did not find support that any of these correlates of decelerated senescence was a substantial mediator of the effect of either of these genetic alterations (with or without caloric restriction) on longevity. Further studies are needed to relate the examined phenotypic characteristics to mechanisms of aging and control of longevity. PMID:25720347

  6. Exercise intervention increases spontaneous locomotion but fails to attenuate dopaminergic system loss in a progressive MPTP model in aged mice.

    PubMed

    Hood, Rebecca L; Liguore, William A; Moore, Cynthia; Pflibsen, Lacey; Meshul, Charles K

    2016-09-01

    While exercise is commonly recommended for PD patients to improve motor function, little is known about the disease-altering potential of exercise. Although others have demonstrated neuroprotective or neurorestorative effects of exercise in animal models of PD, the majority of these studies utilize young animals. In order to assess the effects of exercise intervention in a more clinically relevant model, we have subjected aged mice to progressive 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) lesioning and daily treadmill exercise, initiated early in the course of the disease. The MPTP model elicited a 55% reduction in striatal TH as measured by immunohistochemistry compared to sedentary controls, and exercise did not attenuate this loss in exercised MPTP animals. Furthermore, striatal TH and DAT loss, as assessed by western blotting, were not significantly impacted by treadmill exercise in MPTP-lesioned mice. We did find an increase in spontaneous locomotion in exercised mice that was not decreased by MPTP lesioning. This finding may be due, in part, to an increase in TH expression in the motor cortex in exercised MPTP mice. PMID:27350080

  7. Depletion of TDP-43 affects Drosophila motoneurons terminal synapsis and locomotive behavior.

    PubMed

    Feiguin, Fabian; Godena, Vinay K; Romano, Giulia; D'Ambrogio, Andrea; Klima, Raffaella; Baralle, Francisco E

    2009-05-19

    Pathological modifications in the highly conserved and ubiquitously expressed heterogeneous ribonucleoprotein TDP-43 were recently associated to neurodegenerative diseases including amyotrophic lateral sclerosis (ALS), a late-onset disorder that affects predominantly motoneurons [Neumann, M. et al. (2006) Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Science 314, 130-133, Sreedharan, J. et al. (2008) TDP-43 mutations in familial and sporadic amyotrophic lateral sclerosis. Science 319, 1668-1672, Kabashi, E. et al. (2008) TARDBP mutations in individuals with sporadic and familial amyotrophic lateral sclerosis. Nat. Genet. 40, 572-574]. However, the function of TDP-43 in vivo is unknown and a possible direct role in neurodegeneration remains speculative. Here, we report that flies lacking Drosophila TDP-43 appeared externally normal but presented deficient locomotive behaviors, reduced life span and anatomical defects at the neuromuscular junctions. These phenotypes were rescued by expression of the human protein in a restricted group of neurons including motoneurons. Our results demonstrate the role of this protein in vivo and suggest an alternative explanation to ALS pathogenesis that may be more due to the lack of TDP 43 function than to the toxicity of the aggregates. PMID:19379745

  8. Effects of food deprivation on goal-directed behavior, spontaneous locomotion, and c-Fos immunoreactivity in the amygdala.

    PubMed

    Moscarello, J M; Ben-Shahar, O; Ettenberg, A

    2009-01-30

    Previous work in our laboratory has shown that food deprivation and food presentation produce different patterns of neuronal activity (as measured by c-Fos immunoreactivity) in the medial prefrontal cortex and nucleus accumbens of rats. Since the amygdala has been implicated in both motivational and reinforcement processes and has neuronal connections to both the prefrontal cortex and nucleus accumbens, it was of interest to assess amygdaloid c-Fos immunoreactivity during similar manipulations of food deprivation and presentation. In the current study, c-Fos counts in both basolateral and central amygdalar nuclei were observed to increase in rats 12- and 36-h food deprived (relative to 0-h controls)-an effect reversed by the presentation of either a small or large meal (2.5 or 20g of food). In another experiment, rats working on a progressive ratio schedule of reinforcement exhibited elevated break-points as a function of food deprivation, a result consistent with the view that the feeding manipulations increased the subjects' level of motivation. In contrast, food deprivation reduced the spontaneous locomotor activity of rats, presumably as a result of an inherent energy-conservation strategy when no food is readily available. These data suggest that the state of food deprivation is associated with: (a) enhanced behavioral output only when food is attainable (increased goal-directed behavior, but decreased spontaneous activity), and (b) increased synaptic engagement in neuronal circuits involved in affective valuation and related decision-making (increased c-Fos counts in the amygdala). PMID:18706934

  9. How Temporal and Spatial Aspects of Presenting Visualizations Affect Learning about Locomotion Patterns

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Edelmann, Jorg; Gerjets, Peter

    2012-01-01

    Two studies investigated the effectiveness of dynamic and static visualizations for a perceptual learning task (locomotion pattern classification). In Study 1, seventy-five students viewed either dynamic, static-sequential, or static-simultaneous visualizations. For tasks of intermediate difficulty, dynamic visualizations led to better…

  10. Acoustic and Lexical Representations for Affect Prediction in Spontaneous Conversations

    PubMed Central

    Cao, Houwei; Savran, Arman; Verma, Ragini; Nenkova, Ani

    2014-01-01

    In this article we investigate what representations of acoustics and word usage are most suitable for predicting dimensions of affect|AROUSAL, VALANCE, POWER and EXPECTANCY|in spontaneous interactions. Our experiments are based on the AVEC 2012 challenge dataset. For lexical representations, we compare corpus-independent features based on psychological word norms of emotional dimensions, as well as corpus-dependent representations. We find that corpus-dependent bag of words approach with mutual information between word and emotion dimensions is by far the best representation. For the analysis of acoustics, we zero in on the question of granularity. We confirm on our corpus that utterance-level features are more predictive than word-level features. Further, we study more detailed representations in which the utterance is divided into regions of interest (ROI), each with separate representation. We introduce two ROI representations, which significantly outperform less informed approaches. In addition we show that acoustic models of emotion can be improved considerably by taking into account annotator agreement and training the model on smaller but reliable dataset. Finally we discuss the potential for improving prediction by combining the lexical and acoustic modalities. Simple fusion methods do not lead to consistent improvements over lexical classifiers alone but improve over acoustic models. PMID:25382936

  11. Factors that affect stabilisation times of canine spontaneous hypoadrenocorticism.

    PubMed

    Roberts, E; Boden, L A; Ramsey, I K

    2016-07-23

    The objective of this retrospective study was to examine factors that may have affected the stabilisation times of 50 dogs with spontaneous hypoadrenocorticism that were being treated with fludrocortisone acetate, with particular emphasis on dosing frequency and the concurrent use of prednisolone. Stabilisation was defined as an absence of clinical signs with a sodium:potassium ratio >27:1 and both electrolyte concentrations within a laboratory reference range. It was found that the median time till stabilisation was three months. The frequency of fludrocortisone treatment (once, twice or changed from once to twice a day) had no effect on the stabilisation time. The two groups of dogs that were started and stabilised on once a day or twice a day dosing had a median stabilisation time of two months. However, dogs that failed to stabilise on once a day dosing of fludrocortisone and were then changed onto twice a day dosing then stabilised a median of one month later. Concurrent use of prednisolone resulted in significantly faster stabilisation times. It was concluded that dogs with hypoadrenocorticism should be continued on prednisolone therapy until they are stabilised. If a dog is failing to stabilise on once a day fludrocortisone acetate, a change to twice a day administration could be considered. PMID:27269282

  12. The activity of isolated snail neurons controlling locomotion is affected by glucose

    PubMed Central

    Dyakonova, Varvara; Hernádi, László; Ito, Etsuro; Dyakonova, Taisia; Zakharov, Igor; Sakharov, Dmitri

    2015-01-01

    The involvement of serotonin in mediating hunger-related changes in behavioral state has been described in many invertebrates. However, the mechanisms by which hunger signals to serotonergic cells remain unknown. We tested the hypothesis that serotonergic neurons can directly sense the concentration of glucose, a metabolic indicator of nutritional state. In the snail Lymnaea stagnalis, we demonstrate that completely isolated pedal serotonergic neurons that control locomotion changed their biophysical characteristics in response to glucose application by lowering membrane potential and decreasing the firing rate. Additionally, the excitatory response of the isolated serotonergic neurons to the neuroactive microenvironment of the pedal ganglia was significantly lowered by glucose application. Because hunger has been reported to increase the activity of select neurons and their responses to the pedal ganglia microenvironment, these responses to glucose are in accordance with the hypothesis that direct glucose signaling is involved in the mediation of the hunger-related behavioral state. PMID:27493515

  13. Does Methylphenidate Affect Cystometric Parameters in Spontaneously Hypertensive Rats?

    PubMed Central

    Kim, Khae Hawn; Jung, Ha Bum; Choi, Don Kyoung; Park, Geun Ho; Cho, Sung Tae

    2015-01-01

    Purpose: Methylphenidate (MPH) is one of the most commonly prescribed psychostimulants for attention deficit hyperactivity disorder (ADHD). However, there is limited research on its effects on lower urinary tract function. This study investigated changes in cystometric parameters after intragastric administration of MPH in conscious spontaneously hypertensive rats (SHRs), an animal model of ADHD. Methods: Fourteen- to 16-week-old male SHRs (n=10), weighing between 280 and 315 g, were used. Three micturition cycles were recorded before administering MPH. One hour after each intragastric MPH injection, three cycles of cystometrogram were obtained in the awake condition. Various cystometric parameters were evaluated, including basal pressure (BP), maximal pressure (MP), threshold pressure (TP), bladder capacity (BC), micturition volume (MV), micturition interval (MI), and residual volume (RV). The data were analyzed using paired Student t-tests. Results: Five SHRs were each administered a dose of 3-mg/kg MPH, and the other five received a dose of 6-mg/kg MPH. BP and MP increased significantly in the rats that received the 3-mg/kg MPH injection, but not in those that received the 6-mg/kg injection. BC, MV, and MI significantly increased in the rats that received the 6-mg/kg MPH injection, but not in those that received the 3-mg/kg injection. There were no significant changes in TP after either injection. Conclusions: Significant increases in BC, MV, and MI after the 6-mg/kg MPH injection suggest that the peripheral and the central nervous systems may play important roles in bladder function in those receiving MPH for ADHD. PMID:26126435

  14. Environmental and cow-related factors affect cow locomotion and can cause misclassification in lameness detection systems.

    PubMed

    Van Nuffel, A; Van De Gucht, T; Saeys, W; Sonck, B; Opsomer, G; Vangeyte, J; Mertens, K C; De Ketelaere, B; Van Weyenberg, S

    2016-09-01

    To tackle the high prevalence of lameness, techniques to monitor cow locomotion are being developed in order to detect changes in cows' locomotion due to lameness. Obviously, in such lameness detection systems, alerts should only respond to locomotion changes that are related to lameness. However, other environmental or cow factors can contribute to locomotion changes not related to lameness and hence, might cause false alerts. In this study the effects of wet surfaces, dark environment, age, production level, lactation and gestation stage on cow locomotion were investigated. Data was collected at Institute for Agricultural and Fisheries Research research farm (Melle, Belgium) during a 5-month period. The gait variables of 30 non-lame and healthy Holstein cows were automatically measured every day. In dark environments and on wet walking surfaces cows took shorter, more asymmetrical strides with less step overlap. In general, older cows had a more asymmetrical gait and they walked slower with more abduction. Lactation stage or gestation stage also showed significant association with asymmetrical and shorter gait and less step overlap probably due to the heavy calf in the uterus. Next, two lameness detection algorithms were developed to investigate the added value of environmental and cow data into detection models. One algorithm solely used locomotion variables and a second algorithm used the same locomotion variables and additional environmental and cow data. In the latter algorithm only age and lactation stage together with the locomotion variables were withheld during model building. When comparing the sensitivity for the detection of non-lame cows, sensitivity increased by 10% when the cow data was added in the algorithm (sensitivity was 70% and 80% for the first and second algorithm, respectively). Hence, the number of false alerts for lame cows that were actually non-lame, decreased. This pilot study shows that using knowledge on influencing factors on cow

  15. Does deep brain stimulation of the nucleus ventralis intermedius affect postural control and locomotion in Parkinson's disease?

    PubMed

    Pinter, M M; Murg, M; Alesch, F; Freundl, B; Helscher, R J; Binder, H

    1999-11-01

    The purpose of this study was to evaluate the effect of unilateral stimulation of the nucleus ventralis intermedius (VIM) on parkinsonian signs like postural stability and locomotion with respect to the severity of Parkinson's disease (PD). Seven patients with idiopathic PD were included in the study. Changes in visual cues on postural stability and step initiation were assessed on a fixed platform system with VIM stimulation switched either on (VIM ON) or off (VIM OFF), and compared with a control group of seven age-matched normal individuals. Sway scores (area and path) were significantly (p <0.05) higher in the parkinsonian patients with VIM OFF than with VIM ON as well as compared with the control subjects. No correlation was obtained between extent of sway scores and severity of contralateral tremor after cessation of VIM stimulation. Locomotion parameters, by contrast, were not influenced by VIM stimulation: latency until step initiation and walking-cycle time were the same among parkinsonian patients as among normal individuals, both in the presence and in the absence of VIM stimulation. In conclusion, our results indicate that tremor suppression by VIM stimulation improves postural stability. PMID:10584670

  16. Torsional locomotion

    PubMed Central

    Bigoni, D.; Dal Corso, F.; Misseroni, D.; Bosi, F.

    2014-01-01

    One edge of an elastic rod is inserted into a friction-less and fitting socket head, whereas the other edge is subjected to a torque, generating a uniform twisting moment. It is theoretically shown and experimentally proved that, although perfectly smooth, the constraint realizes an expulsive axial force on the elastic rod, which amount is independent of the shape of the socket head. The axial force explains why screwdrivers at high torque have the tendency to disengage from screw heads and demonstrates torsional locomotion along a perfectly smooth channel. This new type of locomotion finds direct evidence in the realization of a ‘torsional gun’, capable of transforming torque into propulsive force. PMID:25383038

  17. The role of current affect, anticipated affect and spontaneous self-affirmation in decisions to receive self-threatening genetic risk information.

    PubMed

    Ferrer, Rebecca A; Taber, Jennifer M; Klein, William M P; Harris, Peter R; Lewis, Katie L; Biesecker, Leslie G

    2015-01-01

    One reason for not seeking personally threatening information may be negative current and anticipated affective responses. We examined whether current (e.g., worry) and anticipated negative affect predicted intentions to seek sequencing results in the context of an actual genomic sequencing trial (ClinSeq®; n = 545) and whether spontaneous self-affirmation mitigated any (negative) association between affect and intentions. Anticipated affective response negatively predicted intentions to obtain and share results pertaining to both medically actionable and non-actionable disease, whereas current affect was only a marginal predictor. The negative association between anticipated affect and intentions to obtain results pertaining to non-actionable disease was weaker in individuals who were higher in spontaneous self-affirmation. These results have implications for the understanding of current and anticipated affect, self-affirmation and consequential decision-making and contribute to a growing body of evidence on the role of affect in medical decisions. PMID:25482843

  18. Electrokinetic Locomotion

    NASA Astrophysics Data System (ADS)

    Moran, Jeffrey Lawrence

    occurring in the interfacial layer near the particle/solution interface, which play a key role in the locomotion. The model enables one to understand how the rods' motion depends on the properties of their environment, such as hydrogen peroxide concentration, solution electrical conductivity, and solution viscosity. The numerical simulations are complemented with a scaling analysis based on the governing equations, which makes definite, verifiable predictions of these dependences. One of the most important trends that has been observed experimentally is the significant decrease in speed induced by adding sub-millimolar concentrations of inert electrolyte. It is important to understand the physical reasons for the electrolyte-induced speed decrease, in order to know whether it is fundamental to this propulsion mechanism, or if there is some feasible means to circumvent it. Successful completion of this research will result in an improved understanding of the capabilities, as well as the risks and limits of applicability, of the bimetallic nanomotors for applications in nanotechnology and nanomedicine. Potential applications of the rods include the targeted delivery of drugs in the human body, sensing of chemical impurities in drinking water, and as engines to drive fabrication of microscale structures.

  19. Locomotive safety device

    SciTech Connect

    Kleffman, D.R.; Phiffer, L.V.

    1987-01-20

    This patent describes the environment of a longitudinally extending and diesel engine type railroad locomotive classified under a stopped and ''blue flag'' condition, the locomotive having its traction wheels powerable from a high-voltage main-generator. The locomotive is also equipped with a low-voltage auxiliary-generator having electrical circuitry connected to locomotive installed alarm means, to at least one fuel valve for the diesel engine, to locomotive forward-rearward motive directional control, and to locomotive acceleration control. The low-voltage electrical circuitry extends the locomotive longitudinal length and terminates as two endward multi-pins receptacles. The improvement of a locomotive safety device tending to enforce upon would be the locomotive operators ''blue flag'' condition. The locomotive safety device is adapted to removably engaged with a locomotive multipins receptacle and comprises a multi-perforate plug including electrically conductive bushings adapted to be removably inserted into electrically conductive relationship with appropriately selected individual pins of the multi-pins receptacle.

  20. Legless locomotion in lattices

    NASA Astrophysics Data System (ADS)

    Schiebel, Perrin; Dai, Jin; Gong, Chaohui; Serrano, Miguel M.; Mendelson, Joseph R., III; Choset, Howie; Goldman, Daniel I.

    2015-03-01

    By propagating waves from head to tail, limbless organisms like snakes can traverse terrain composed of rocks, foliage, soil and sand. Previous research elucidated how rigid obstacles influence snake locomotion by studying a model terrain-symmetric lattices of pegs placed in hard ground. We want to understand how different substrate-body interaction modes affect performance in desert-adapted snakes during transit of substrates composed of both rigid obstacles and granular media (GM). We tested Chionactis occipitalis, the Mojave shovel-nosed snake, in two laboratory treatments: lattices of 0 . 64 cm diameter obstacles arrayed on both a hard, slick substrate and in a GM of ~ 0 . 3 mm diameter glass particles. For all lattice spacings, d, speed through the hard ground lattices was less than that in GM lattices. However, maximal undulation efficiencies ηu (number of body lengths advanced per undulation cycle) in both treatments were comparable when d was intermediate. For other d, ηu was lower than this maximum in hard ground lattices, while on GM, ηu was insensitive to d. To systematically explore such locomotion, we tested a physical robot model of the snake; performance depended sensitively on base substrate, d and body wave parameters.

  1. Non-motorized voluntary running does not affect experimental and spontaneous metastasis in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The present study investigated the effects of non-motorized voluntary running on experimental metastasis of B16BL/6 melanoma and spontaneous metastasis of Lewis lung carcinoma (LLC) in male C57BL/6 mice. After 9 weeks of running, mice (n = 30 per group) received an intravenous injection of B16BL/6 c...

  2. Crocin loaded nano-emulsions: Factors affecting emulsion properties in spontaneous emulsification.

    PubMed

    Mehrnia, Mohammad-Amin; Jafari, Seid-Mahdi; Makhmal-Zadeh, Behzad S; Maghsoudlou, Yahya

    2016-03-01

    Spontaneous emulsification may be used for encapsulating bioactive compounds in food and pharmaceutical industry. It has several advantages over high energy and other low energy methods including, protecting sensitive compounds against severe conditions of high energy method and its ability to minimize surfactant, removal of cosurfactant and thermal stability compared with other low energy methods. In this study, we examined possibility of encapsulating highly soluble crocin in W/O micro-emulsions using spontaneous method which further could be used for making double emulsions. Nonionic surfactants of Span 80 and polyglycerol polyricinoleate (PGPR) were used for making micro-emulsions that showed the high potential of PGPR for spontaneous method. Surfactant to water ratio (SWR%) was evaluated to find the highest amount of aqueous phase which can be dispersed in organic phase. Droplet size decreased by increasing SWR toward the SWR=100% which had the smallest droplet size and then increased at higher levels of surfactant. By increasing SWR, shear viscosity increased which showed the high effect of PGPR on rheological properties. This study shows in addition to W/O micro-emulsions, spontaneous method could be used for preparing stable O/W micro-emulsions. PMID:26708427

  3. Rostral spinal cord segments are sufficient to generate a rhythm for both locomotion and scratching but affect their hip extensor phases differently.

    PubMed

    Hao, Zhao-Zhe; Meier, Megan L; Berkowitz, Ari

    2014-07-01

    Rostral segments of the spinal cord hindlimb enlargement are more important than caudal segments for generating locomotion and scratching rhythms in limbed vertebrates, but the adequacy of rostral segments has not been directly compared between locomotion and scratching. We separated caudal segments from immobilized low-spinal turtles by sequential spinal cord transections. After separation of the caudal four segments of the five-segment hindlimb enlargement, the remaining enlargement segment and five preenlargement segments still produced rhythms for forward swimming and both rostral and pocket scratching. The swimming rhythm frequency was usually maintained. Some animals continued to generate swimming and scratching rhythms even with no enlargement segments remaining, using only preenlargement segments. The preenlargement segments and rostral-most enlargement segment were also sufficient to maintain hip flexor (HF) motoneuron quiescence between HF bursts [which normally occurs during each hip extensor (HE) phase] during swimming. In contrast, the HF-quiescent phase was increasingly absent (i.e., HE-phase deletions) during rostral and pocket scratching. Moreover, respiratory motoneurons that normally burst during HE bursts continued to burst during the HF quiescence of swimming even with the caudal segments separated. Thus the same segments are sufficient to generate the basic rhythms for both locomotion and scratching. These segments are also sufficient to produce a reliable HE phase during locomotion but not during rostral or pocket scratching. We hypothesize that the rostral HE-phase interneurons that rhythmically inhibit HF motoneurons and interneurons are sufficient to generate HF quiescence during HE-biased swimming but not during the more HF-biased rostral and pocket scratching. PMID:24717347

  4. Railroad and locomotive technology roadmap.

    SciTech Connect

    Stodolsky, F.; Gaines, L.; Energy Systems

    2003-02-24

    Railroads are important to the U.S. economy. They transport freight efficiently, requiring less energy and emitting fewer pollutants than other modes of surface transportation. While the railroad industry has steadily improved its fuel efficiency--by 16% over the last decade--more can, and needs to, be done. The ability of locomotive manufacturers to conduct research into fuel efficiency and emissions reduction is limited by the small number of locomotives manufactured annually. Each year for the last five years, the two North American locomotive manufacturers--General Electric Transportation Systems and the Electro-Motive Division of General Motors--have together sold about 800 locomotives in the United States. With such a small number of units over which research costs can be spread, outside help is needed to investigate all possible ways to reduce fuel usage and emissions. Because fuel costs represent a significant portion of the total operating costs of a railroad, fuel efficiency has always been an important factor in the design of locomotives and in the operations of a railroad. However, fuel efficiency has recently become even more critical with the introduction of strict emission standards by the U.S. Environmental Protection Agency, to be implemented in stages (Tiers 0, 1, and 2) between 2000 and 2005. Some of the technologies that could be employed to meet the emission standards may negatively affect fuel economy--by as much as 10-15% when emissions are reduced to Tier 1 levels. Lowering fuel economy by that magnitude would have a serious impact on the cost to the consumer of goods shipped by rail, on the competitiveness of the railroad industry, and on this country's dependence on foreign oil. Clearly, a joint government/industry R&D program is needed to help catalyze the development of advanced technologies that will substantially reduce locomotive engine emissions while also improving train system energy efficiency. DOE convened an industry

  5. Cross-fostering differentially affects ADHD-related behaviors in spontaneously hypertensive rats.

    PubMed

    Gauthier, Angela C; DeAngeli, Nicole E; Bucci, David J

    2015-03-01

    Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered to an unfamiliar dam of either the same or different strain. Behavioral testing took place when the rats reached adulthood. Locomotor hyperactivity was completely dependent on the strain of the offspring. In contrast, social behavior was primarily determined by the strain of the mother, while attentional orienting behavior was influenced by both the strain of the offspring and the strain of the dam. Anxiety-related behavior was influenced by an interaction between offspring and dam strain. PMID:25647439

  6. Cross-Fostering Differentially Affects ADHD-Related Behaviors in Spontaneously Hypertensive Rats

    PubMed Central

    Gauthier, Angela C.; DeAngeli, Nicole E.; Bucci, David J.

    2014-01-01

    Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered to an unfamiliar dam of either the same or different strain. Behavioral testing took place when the rats reached adulthood. Locomotor hyperactivity was completely dependent on the strain of the offspring. In contrast, social behavior was primarily determined by the strain of the mother, while attentional orienting behavior was influenced by both the strain of the offspring and the strain of the dam. Anxiety-related behavior was influenced by an interaction between offspring and dam strain. PMID:25647439

  7. Oxytocin affects spontaneous neural oscillations in trauma-exposed war veterans.

    PubMed

    Eidelman-Rothman, Moranne; Goldstein, Abraham; Levy, Jonathan; Weisman, Omri; Schneiderman, Inna; Mankuta, David; Zagoory-Sharon, Orna; Feldman, Ruth

    2015-01-01

    Exposure to combat-related trauma often leads to lifetime functional impairments. Previous research demonstrated the effects of oxytocin (OT) administration on brain regions implicated in post-traumatic stress disorder (PTSD); yet OT's effects on brain patterns in trauma-exposed veterans have not been studied. In the current study the effects of OT on spontaneous brain oscillatory activity were measured in 43 veterans using magnetoencephalography (MEG): 28 veterans who were exposed to a combat-related trauma and 15 trauma-unexposed controls. Participants participated in two experimental sessions and were administered OT or placebo (PBO) in a double-blind, placebo-control, within-subject design. Following OT/PBO administration, participants underwent a whole-head MEG scan. Plasma and salivary OT levels were assessed each session. Spontaneous brain activity measured during a 2-min resting period was subjected to source-localization analysis. Trauma-exposed veterans showed higher resting-state alpha (8-13 Hz) activity compared to controls in the left dorsolateral prefrontal cortex (dlPFC), specifically in the superior frontal gyrus (SFG) and the middle frontal gyrus (MFG), indicating decreased neural activity in these regions. The higher alpha activity was "normalized" following OT administration and under OT, group differences were no longer found. Increased resting-state alpha was associated with lower baseline plasma OT, reduced salivary OT reactivity, and more re-experiencing symptoms. These findings demonstrate effects of OT on resting-state brain functioning in prefrontal regions subserving working memory and cognitive control, which are disrupted in PTSD. Results raise the possibility that OT, traditionally studied in social contexts, may also enhance performance in cognitive tasks associated with working memory and cognitive control following trauma exposure. PMID:26175673

  8. Oxytocin affects spontaneous neural oscillations in trauma-exposed war veterans

    PubMed Central

    Eidelman-Rothman, Moranne; Goldstein, Abraham; Levy, Jonathan; Weisman, Omri; Schneiderman, Inna; Mankuta, David; Zagoory-Sharon, Orna; Feldman, Ruth

    2015-01-01

    Exposure to combat-related trauma often leads to lifetime functional impairments. Previous research demonstrated the effects of oxytocin (OT) administration on brain regions implicated in post-traumatic stress disorder (PTSD); yet OT’s effects on brain patterns in trauma-exposed veterans have not been studied. In the current study the effects of OT on spontaneous brain oscillatory activity were measured in 43 veterans using magnetoencephalography (MEG): 28 veterans who were exposed to a combat-related trauma and 15 trauma-unexposed controls. Participants participated in two experimental sessions and were administered OT or placebo (PBO) in a double-blind, placebo-control, within-subject design. Following OT/PBO administration, participants underwent a whole-head MEG scan. Plasma and salivary OT levels were assessed each session. Spontaneous brain activity measured during a 2-min resting period was subjected to source-localization analysis. Trauma-exposed veterans showed higher resting-state alpha (8–13 Hz) activity compared to controls in the left dorsolateral prefrontal cortex (dlPFC), specifically in the superior frontal gyrus (SFG) and the middle frontal gyrus (MFG), indicating decreased neural activity in these regions. The higher alpha activity was “normalized” following OT administration and under OT, group differences were no longer found. Increased resting-state alpha was associated with lower baseline plasma OT, reduced salivary OT reactivity, and more re-experiencing symptoms. These findings demonstrate effects of OT on resting-state brain functioning in prefrontal regions subserving working memory and cognitive control, which are disrupted in PTSD. Results raise the possibility that OT, traditionally studied in social contexts, may also enhance performance in cognitive tasks associated with working memory and cognitive control following trauma exposure. PMID:26175673

  9. Factors Affecting Trial Without Catheter for First Spontaneous Acute Urinary Retention

    PubMed Central

    Vaddi, Surya Prakash; Godala, Chandra-Mohan; Reddy, V. Vijaya Kumar; Sambar, Venkat Krishna

    2013-01-01

    Purpose To find the association of trial without catheter (TWOC) outcome for first spontaneous acute urinary retention (AUR) in benign prostatic obstruction with age, prior lower urinary tract symptoms (LUTS), retention volume at catheterization (RV), and size of prostate. Methods Our prospective observational analytical (interventional) study enrolled 77 cases of spontaneous AUR over 24 months. After clinical evaluation, digital rectal examination, and transabdominal ultrasonography, all patients were catheterized per urethra and their RV was recorded. TWOC was administered after 2 or 3 doses of 0.4 mg tamsulosin-oral absorption control system and after 48-72 hours had passed. A successful endpoint was defined as a maximum flow-rate, >5 mL/sec; voided volume, >100 mL; postvoid residue, <200 mL; and voiding within 6 hours of catheter removal. Data obtained from 58 patients were analyzed after excluding the cases lost to follow-up and secondary exclusion. Age, RV, duration of LUTS, and prostate volume on examination and ultrasonography (PUSG) were recorded and statistically analyzed. Prostate-specific antigen levels were obtained on follow-up and cases of cancer, as seen on transrectal ultrasound-guided biopsy, were secondarily excluded. Results The patients had a mean age of 65.89±8.67 years. Prior LUTS was seen in 35 patients (2.07±2.91 months). The mean PUSG and RV were 46.81±20.58 mL and 854.8±36.26 mL, respectively. Thirty patients underwent a successful TWOC; a mean age of 63.13±8.58 years (mean±standard deviation; unpaired t-test; P=0.0053) and a PUSG of ≤45 mL (Pearson chi-square test; P=0.0427) were significantly associated with a successful outcome. Conclusions There is a significant association between TWOC outcome, age (P=0.0053), and PUSG (P=0.0427). PMID:24143290

  10. Factors affecting the spontaneous adsorption of Bi(III) onto Pt and PtRu nanoparticles

    NASA Astrophysics Data System (ADS)

    Sawy, Ehab N. El; Khan, M. Akhtar; Pickup, Peter G.

    2016-02-01

    The influence of Bi(III) concentration and pH on the spontaneous adsorption of Bi species onto Pt nanoparticles has been systematically investigated in order to identify the adsorbing species, determine whether the nature of the adsorbing species changes, and investigate whether the activities of the resulting Bi decorated particles for formic acid oxidation can be influenced. The adsorption of Bi follows a Temkin-type isotherm, with a pH dependence indicating that the adsorbing species is [Bi6O4(OH)4]6+. Activities of Bi decorated Pt nanoparticles for formic acid oxidation are strongly influenced by the Bi coverage, with a maximum enhancement of a factor of ca. 60 at a coverage of 70%, but not by the Bi(III) concentration or pH used to adsorb the Bi species, other than through their influence on Bi coverage. These results support the conclusion that the adsorbing species is [Bi6O4(OH)4]6+ under all conditions investigated. Adsorbed Bi also activates PtRu nanoparticles for formic acid oxidation, although the effect is not as strong as for Pt. The maximum enhancement observed was only a factor of ca. 7. This has been attributed to attenuation of the effects of Bi adatoms that are adsorbed at Ru sites.

  11. Negative affect and 24-hour ambulatory physiological recordings as predictors of spontaneous improvement of medically unexplained symptoms.

    PubMed

    Houtveen, Jan H; VAN Doornen, Lorenz J P

    2008-12-01

    The predictive value for spontaneous improvement in individuals suffering from medically unexplained symptoms (MUS) was explored of (1) anxiety and depression obtained from questionnaires, (2) negative affective states obtained from experience-sampling, and (3) ambulatory-assessed real-life physiological recordings. Sixty-seven individuals with MUS and 61 healthy controls were included. Twenty-four hour ambulatory recordings of cardiac autonomic activity, respiration, end-tidal CO(2) and saliva cortisol were combined with experience-sampling of somatic complaints and mood. Complaints were assessed again after one year. Although a reduction in symptoms (25%) was found, this could not be predicted from initial anxiety and depression. Improvement was somewhat related to relatively low diary reports of fatigue, especially in the late-afternoon and evening (3% variance explained). From the physiological measures only relatively high PetCO(2) values in the morning predicted improvement (5% explained). It was concluded that spontaneous recovery from MUS is hard to predict from self-reported distress and ambulatory physiological recordings. PMID:18771476

  12. OPERANT CONDITIONING OF A SPINAL REFLEX CAN IMPROVE LOCOMOTION AFTER SPINAL CORD INJURY IN HUMANS

    PubMed Central

    Thompson, Aiko K.; Pomerantz, Ferne; Wolpaw, Jonathan R.

    2013-01-01

    Operant conditioning protocols can modify the activity of specific spinal cord pathways and can thereby affect behaviors that use these pathways. To explore the therapeutic application of these protocols, we studied the impact of down-conditioning the soleus H-reflex in people with impaired locomotion caused by chronic incomplete spinal cord injury. After a baseline period in which soleus H-reflex size was measured and locomotion was assessed, subjects completed either 30 H-reflex down-conditioning sessions (DC subjects) or 30 sessions in which the H-reflex was simply measured (Unconditioned (UC) subjects), and locomotion was reassessed. Over the 30 sessions, the soleus H-reflex decreased in two-thirds of the DC subjects (a success rate similar to that in normal subjects) and remained smaller several months later. In these subjects, locomotion became faster and more symmetrical, and the modulation of EMG activity across the step-cycle increased bilaterally. Furthermore, beginning about halfway through the conditioning sessions, all of these subjects commented spontaneously that they were walking faster and farther in their daily lives, and several noted less clonus, easier stepping, and/or other improvements. The H-reflex did not decrease in the other DC subjects or in any of the UC subjects; and their locomotion did not improve. These results suggest that reflex conditioning protocols can enhance recovery of function after incomplete spinal cord injuries and possibly in other disorders as well. Because they are able to target specific spinal pathways, these protocols could be designed to address each individual’s particular deficits, and might thereby complement other rehabilitation methods. PMID:23392666

  13. Goal Directed Locomotion and Balance Control in Autistic Children

    ERIC Educational Resources Information Center

    Vernazza-Martin, S.; Martin, N.; Vernazza, A.; Lepellec-Muller, A.; Rufo, M.; Massion, J.; Assaiante, C.

    2005-01-01

    This article focuses on postural anticipation and multi-joint coordination during locomotion in healthy and autistic children. Three questions were addressed: (1) Are gait parameters modified in autistic children? (2) Is equilibrium control affected in autistic children? (3) Is locomotion adjusted to the experimenter-imposed goal? Six healthy…

  14. Effects of Voluntary Locomotion and Calcitonin Gene-Related Peptide on the Dynamics of Single Dural Vessels in Awake Mice

    PubMed Central

    Gao, Yu-Rong

    2016-01-01

    The dura mater is a vascularized membrane surrounding the brain and is heavily innervated by sensory nerves. Our knowledge of the dural vasculature has been limited to pathological conditions, such as headaches, but little is known about the dural blood flow regulation during behavior. To better understand the dynamics of dural vessels during behavior, we used two-photon laser scanning microscopy (2PLSM) to measure the diameter changes of single dural and pial vessels in the awake mouse during voluntary locomotion. Surprisingly, we found that voluntary locomotion drove the constriction of dural vessels, and the dynamics of these constrictions could be captured with a linear convolution model. Dural vessel constrictions did not mirror the large increases in intracranial pressure (ICP) during locomotion, indicating that dural vessel constriction was not caused passively by compression. To study how behaviorally driven dynamics of dural vessels might be altered in pathological states, we injected the vasodilator calcitonin gene-related peptide (CGRP), which induces headache in humans. CGRP dilated dural, but not pial, vessels and significantly reduced spontaneous locomotion but did not block locomotion-induced constrictions in dural vessels. Sumatriptan, a drug commonly used to treat headaches, blocked the vascular and behavioral the effects of CGRP. These findings suggest that, in the awake animal, the diameters of dural vessels are regulated dynamically during behavior and during drug-induced pathological states. SIGNIFICANT STATEMENT The vasculature of the dura has been implicated in the pathophysiology of headaches, but how individual dural vessels respond during behavior, both under normal conditions and after treatment with the headache-inducing peptide calcitonin gene-related peptide (CGRP), is poorly understood. To address these issues, we imaged individual dural vessels in awake mice and found that dural vessels constricted during voluntary locomotion, and

  15. Deletion of dopamine D1 and D3 receptors differentially affects spontaneous behaviour and cocaine-induced locomotor activity, reward and CREB phosphorylation.

    PubMed

    Karasinska, Joanna M; George, Susan R; Cheng, Regina; O'Dowd, Brian F

    2005-10-01

    Co-localization of dopamine D1 and D3 receptors in striatal neurons suggests that these two receptors interact at a cellular level in mediating dopaminergic function including psychostimulant-induced behaviour. To study D1 and D3 receptor interactions in cocaine-mediated effects, cocaine-induced locomotion and reward in mice lacking either D1, D3 or both receptors were analysed. Spontaneous locomotor activity was increased in D1-/- and D1-/-D3-/- mice and D1-/-D3-/- mice did not exhibit habituation of spontaneous rearing activity. Cocaine (20 mg/kg) increased locomotor activity in wild-type and D3-/- mice, failed to stimulate activity in D1-/- mice and reduced activity in D1-/-D3-/- mice. In the conditioned place preference, all groups exhibited reward at 5, 10 and 20 mg/kg of cocaine. D1-/-D3-/- mice did not demonstrate preference at 2.5 mg/kg of cocaine although preference was observed in wild-type, D1-/- and D3-/- mice. The transcription factor cAMP-responsive element binding protein (CREB) is activated by phosphorylation in striatal regions following dopamine receptor activation. Striatal pCREB levels following acute cocaine were increased in wild-type and D3-/- mice and decreased in D1-/- and D1-/-D3-/- mice. After repeated administration of 2.5 mg/kg of cocaine, D1-/- mice had lower pCREB levels in caudate-putamen and nucleus accumbens. Our findings suggest that, although spontaneous and cocaine-induced horizontal activity depended mainly on the presence of the D1 receptor, there may be crosstalk between D1 and D3 receptors in rearing habituation and the perception of cocaine reward at low doses of the drug. Furthermore, alterations in pCREB levels were associated with changes in cocaine-induced locomotor activity but not reward. PMID:16197514

  16. Compensations during Unsteady Locomotion.

    PubMed

    Qiao, Mu; Jindrich, Devin L

    2014-12-01

    Locomotion in a complex environment is often not steady, but the mechanisms used by animals to power and control unsteady locomotion (stability and maneuverability) are not well understood. We use behavioral, morphological, and impulsive perturbations to determine the compensations used during unsteady locomotion. At the level both of the whole-body and of joints, quasi-stiffness models are useful for describing adjustments to the functioning of legs and joints during maneuvers. However, alterations to the mechanics of legs and joints often are distinct for different phases of the step cycle or for specific joints. For example, negotiating steps involves independent changes of leg stiffness during compression and thrust phases of stance. Unsteady locomotion also involves parameters that are not part of the simplest reduced-parameter models of locomotion (e.g., the spring-loaded inverted pendulum) such as moments of the hip joint. Extensive coupling among translational and rotational parameters must be taken into account to stabilize locomotion or maneuver. For example, maneuvers with morphological perturbations (increased rotational inertial turns) involve changes to several aspects of movement, including the initial conditions of rotation and ground-reaction forces. Coupled changes to several parameters may be employed to control maneuvers on a trial-by-trial basis. Compensating for increased rotational inertia of the body during turns is facilitated by the opposing effects of several mechanical and behavioral parameters. However, the specific rules used by animals to control translation and rotation of the body to maintain stability or maneuver have not been fully characterized. We initiated direct-perturbation experiments to investigate the strategies used by humans to maintain stability following center-of-mass (COM) perturbations. When walking, humans showed more resistance to medio-lateral perturbations (lower COM displacement). However, when running, humans

  17. Fuelcell Prototype Locomotive

    SciTech Connect

    David L. Barnes

    2007-09-28

    An international industry-government consortium is developing a fuelcell hybrid switcher locomotive for commercial railway applications and power-to-grid generation applications. The current phase of this on-going project addresses the practicalities of on-board hydrogen storage, fuelcell technology, and hybridity, all with an emphasis on commercially available products. Through practical evaluation using designs from Vehicle Projects’ Fuelcell-Powered Underground Mine Loader Project, the configuration of the fuelcell switcher locomotive changed from using metal-hydride hydrogen storage and a pure fuelcell power plant to using compressed hydrogen storage, a fuelcell-battery hybrid power plant, and fuelcell stack modules from Ballard Power Systems that have been extensively used in the Citaro bus program in Europe. The new overall design will now use a RailPower battery hybrid Green Goat™ as the locomotive platform. Keeping the existing lead-acid batteries, we will replace the 205 kW diesel gen-set with 225 kW of net fuelcell power, remove the diesel fuel tank, and place 14 compressed hydrogen cylinders, capable of storing 70 kg of hydrogen at 350 bar, on the roof. A detailed design with associated CAD models will allow a complete build of the fuelcell-battery hybrid switcher locomotive in the next funded phase.

  18. Exposure to ultrafine carbon particles at levels below detectable pulmonary inflammation affects cardiovascular performance in spontaneously hypertensive rats

    PubMed Central

    Upadhyay, Swapna; Stoeger, Tobias; Harder, Volkar; Thomas, Ronald F; Schladweiler, Mette C; Semmler-Behnke, Manuela; Takenaka, Shinji; Karg, Erwin; Reitmeir, Peter; Bader, Michael; Stampfl, Andreas; Kodavanti, Urmila P; Schulz, Holger

    2008-01-01

    Background Exposure to particulate matter is a risk factor for cardiopulmonary disease but the underlying molecular mechanisms remain poorly understood. In the present study we sought to investigate the cardiopulmonary responses on spontaneously hypertensive rats (SHRs) following inhalation of UfCPs (24 h, 172 μg·m-3), to assess whether compromised animals (SHR) exhibit a different response pattern compared to the previously studied healthy rats (WKY). Methods Cardiophysiological response in SHRs was analyzed using radiotelemetry. Blood pressure (BP) and its biomarkers plasma renin-angiotensin system were also assessed. Lung and cardiac mRNA expressions for markers of oxidative stress (hemeoxygenase-1), blood coagulation (tissue factor, plasminogen activator inhibitor-1), and endothelial function (endothelin-1, and endothelin receptors A and B) were analyzed following UfCPs exposure in SHRs. UfCPs-mediated inflammatory responses were assessed from broncho-alveolar-lavage fluid (BALF). Results Increased BP and heart rate (HR) by about 5% with a lag of 1–3 days were detected in UfCPs exposed SHRs. Inflammatory markers of BALF, lung (pulmonary) and blood (systemic) were not affected. However, mRNA expression of hemeoxygenase-1, endothelin-1, endothelin receptors A and B, tissue factor, and plasminogen activator inhibitor showed a significant induction (~2.5-fold; p < 0.05) with endothelin 1 being the maximally induced factor (6-fold; p < 0.05) on the third recovery day in the lungs of UfCPs exposed SHRs; while all of these factors – except hemeoxygenase-1 – were not affected in cardiac tissues. Strikingly, the UfCPs-mediated altered BP is paralleled by the induction of renin-angiotensin system in plasma. Conclusion Our finding shows that UfCPs exposure at levels which does not induce detectable pulmonary neutrophilic inflammation, triggers distinct effects in the lung and also at the systemic level in compromised SHRs. These effects are characterized by

  19. Compliant Synergies in Locomotion

    NASA Astrophysics Data System (ADS)

    Travers, Matthew; Choset, Howie; Goldman @ Georgia Tech. Physics Department Collaboration

    Biological systems appear to have natural mechanisms that allow them to readily compensate for unexpected environmental variations when compared to their mechanical (i.e., robotic) counterparts. We hypothesize that the basis for this discrepancy is almost innate: what biology appears to be born with, built-in mechanisms for coordinating their many degrees of freedom, we struggle to ``program.'' We therefore look toward biology for inspiration. In particular, we are interested in kinematic synergies, low-dimensional representations that explicitly encode the underlying structure of how systems coordinate their internal degrees of freedom to achieve high-level tasks. In this work, we derive parametric representations of kinematic synergies and present a new compliant locomotion control framework that enables the parameters to be directly controlled in response to external disturbances. We present results of this framework implemented on two separate platforms, a snake-like and hexapod robot. Our results show that, using synergies, the locomotion control of these very different systems can be reduced to simple, extremely capable, and common forms, thus offering new insights into both robotic as well as biological locomotion in complex terrains.

  20. Advanced robot locomotion.

    SciTech Connect

    Neely, Jason C.; Sturgis, Beverly Rainwater; Byrne, Raymond Harry; Feddema, John Todd; Spletzer, Barry Louis; Rose, Scott E.; Novick, David Keith; Wilson, David Gerald; Buerger, Stephen P.

    2007-01-01

    This report contains the results of a research effort on advanced robot locomotion. The majority of this work focuses on walking robots. Walking robot applications include delivery of special payloads to unique locations that require human locomotion to exo-skeleton human assistance applications. A walking robot could step over obstacles and move through narrow openings that a wheeled or tracked vehicle could not overcome. It could pick up and manipulate objects in ways that a standard robot gripper could not. Most importantly, a walking robot would be able to rapidly perform these tasks through an intuitive user interface that mimics natural human motion. The largest obstacle arises in emulating stability and balance control naturally present in humans but needed for bipedal locomotion in a robot. A tracked robot is bulky and limited, but a wide wheel base assures passive stability. Human bipedal motion is so common that it is taken for granted, but bipedal motion requires active balance and stability control for which the analysis is non-trivial. This report contains an extensive literature study on the state-of-the-art of legged robotics, and it additionally provides the analysis, simulation, and hardware verification of two variants of a proto-type leg design.

  1. Interactions between locomotion and ventilation in tetrapods.

    PubMed

    Boggs, Dona F

    2002-10-01

    Interactions between locomotion and ventilation have now been studied in several species of reptiles, birds and mammals, from a variety of perspectives. Among these perspectives are neural interactions of separate but linked central controllers; mechanical impacts of locomotion upon ventilatory pressures and flows; and the extent to which the latter may affect gas exchange and the energetics of exercise. A synchrony, i.e. 1:1 pattern of coordination, is observed in many running mammals once they achieve galloping speeds, as well as in flying bats, some flying birds and hopping marsupials. Other, non-1:1, patterns of coordination are seen in trotting and walking quadrupeds, as well as running bipedal humans and running and flying birds. There is evidence for an energetic advantage to coordination of locomotor and respiratory cycles for flying birds and running mammals. There is evidence for a mechanical constraint upon ventilation by locomotion for some reptiles (e.g. iguana), but not for others (e.g. varanids and crocodilians). In diving birds the impact of wing flapping or foot paddling on differential air sac pressures enhances gas exchange during the breath hold by improving diffusive and convective movement of air sac oxygen to parabronchi. This paper will review the current state of our knowledge of such influences of locomotion upon respiratory system function. PMID:12208300

  2. Chronic treatment with epigallocatechin gallate reduces motor hyperactivity and affects in vitro tested intestinal motility of spontaneously hypertensive rats

    PubMed Central

    Potenza, Maria Assunta; Montagnani, Monica; Nacci, Carmela; De Salvia, Maria Antonietta

    2016-01-01

    Background Green tea catechins seem to contribute toward reducing body weight and fat. Objective We aimed to investigate whether chronic administration of (–)-epigallocatechin-3-gallate (EGCG), the most abundant catechin of green tea, reduces weight gain in spontaneously hypertensive rats (SHR), an animal model of metabolic syndrome, by increasing motor activity and/or by altering gastrointestinal motility. Design Nine-week-old SHR were randomly assigned to two groups and treated by gavage for 3 weeks with vehicle dimethyl sulfoxide or EGCG (200 mg/kg/day). Age-matched Wistar-Kyoto (WKY) control rats were treated with vehicle alone. The effect of chronic administration of EGCG was evaluated on open-field motor activity and on ex vivo colonic and duodenal motility. Moreover, in vitro acute effect of 20-min incubation with EGCG (100 µM) or vehicle was evaluated in colonic and duodenal specimens from untreated WKY rats and SHR. Results Vehicle-treated SHR were normoglycemic and hyperinsulinemic, and showed a reduction of plasma adiponectin when compared to vehicle-treated WKY rats. In addition, consistent with fasting glucose and insulin values, vehicle-treated SHR were more insulin resistant than age-matched vehicle-treated WKY rats. Chronic treatment for 3 weeks with EGCG improved insulin sensitivity, raised plasma adiponectin levels, and reduced food intake and weight gain in SHR. Vehicle-treated SHR showed increased open-field motor activity (both crossings and rearings) when tested after each week of treatment. The overall hyperactivity of vehicle-treated SHR was significantly reduced to the levels of vehicle-treated WKY rats after 2 and 3 weeks of EGCG treatment. Colonic and duodenal preparations obtained from SHR chronically treated in vivo with EGCG showed reduced responses to carbachol (0.05–5 µM) and increased inhibitory response to electrical field stimulation (EFS, 1–10 Hz, 13 V, 1 msec, 10-sec train duration), respectively. In vitro acute EGCG

  3. Arousal and locomotion make distinct contributions to cortical activity patterns and visual encoding.

    PubMed

    Vinck, Martin; Batista-Brito, Renata; Knoblich, Ulf; Cardin, Jessica A

    2015-05-01

    Spontaneous and sensory-evoked cortical activity is highly state-dependent, yet relatively little is known about transitions between distinct waking states. Patterns of activity in mouse V1 differ dramatically between quiescence and locomotion, but this difference could be explained by either motor feedback or a change in arousal levels. We recorded single cells and local field potentials from area V1 in mice head-fixed on a running wheel and monitored pupil diameter to assay arousal. Using naturally occurring and induced state transitions, we dissociated arousal and locomotion effects in V1. Arousal suppressed spontaneous firing and strongly altered the temporal patterning of population activity. Moreover, heightened arousal increased the signal-to-noise ratio of visual responses and reduced noise correlations. In contrast, increased firing in anticipation of and during movement was attributable to locomotion effects. Our findings suggest complementary roles of arousal and locomotion in promoting functional flexibility in cortical circuits. PMID:25892300

  4. Locomotion: dealing with friction.

    PubMed

    Radhakrishnan, V

    1998-05-12

    To move on land, in water, or in the air, even at constant speed and at the same level, always requires an expenditure of energy. The resistance to motion that has to be overcome is of many different kinds depending on size, speed, and the characteristics of the medium, and is a fascinating subject in itself. Even more interesting are nature's stratagems and solutions toward minimizing the effort involved in the locomotion of different types of living creatures, and humans' imitations and inventions in an attempt to do at least as well. PMID:9576902

  5. Locomotion: Dealing with friction

    PubMed Central

    Radhakrishnan, V.

    1998-01-01

    To move on land, in water, or in the air, even at constant speed and at the same level, always requires an expenditure of energy. The resistance to motion that has to be overcome is of many different kinds depending on size, speed, and the characteristics of the medium, and is a fascinating subject in itself. Even more interesting are nature’s stratagems and solutions toward minimizing the effort involved in the locomotion of different types of living creatures, and humans’ imitations and inventions in an attempt to do at least as well. PMID:9576902

  6. Does dilation and curettage versus expectant management for spontaneous abortion in patients undergoing in vitro fertilization affect subsequent endometrial development?

    PubMed

    Moon, Kimberly S; Richter, Kevin S; Levy, Michael J; Widra, Eric A

    2009-11-01

    In in vitro fertilization patients, treatment of spontaneous abortion with dilation and curettage (D&C) versus expectant management has no long-term effect on subsequent endometrial development, as measured by change in endometrial thickness. A transient reduction in endometrial thickness was found within the first 6 months after D&C, which is a novel finding, but it is likely to have little or no effect on pregnancy rates given the small absolute effect on endometrial thickness. PMID:19560759

  7. Terrestrial locomotion in arachnids.

    PubMed

    Spagna, Joseph C; Peattie, Anne M

    2012-05-01

    In this review, we assess the current state of knowledge on terrestrial locomotion in Arachnida. Arachnids represent a single diverse (>100,000 species) clade containing well-defined subgroups (at both the order and subordinal levels) that vary morphologically around a basic body plan, yet exhibit highly disparate limb usage, running performance, and tarsal attachment mechanisms. Spiders (Araneae), scorpions (Scorpiones), and harvestmen (Opiliones) have received the most attention in the literature, while some orders have never been subject to rigorous mechanical characterization. Most well-characterized taxa move with gaits analogous to the alternating tripod gaits that characterize fast-moving Insecta - alternating tetrapods or alternating tripods (when one pair of legs is lifted from the ground for some other function). However, between taxa, there is considerable variation in the regularity of phasing between legs. Both large and small spiders appear to show a large amount of variation in the distribution of foot-ground contact, even between consecutive step-cycles of a single run. Mechanisms for attachment to vertical surfaces also vary, and may depend on tufts of adhesive hairs, fluid adhesives, silks, or a combination of these. We conclude that Arachnida, particularly with improvements in microelectronic force sensing technology, can serve as a powerful study system for understanding the kinematics, dynamics, and ecological correlates of sprawled-posture locomotion. PMID:22326455

  8. A fundamental mechanism of legged locomotion with hip torque and leg damping.

    PubMed

    Shen, Z H; Seipel, J E

    2012-12-01

    New models and theories of legged locomotion are needed to better explain and predict the robustly stable legged locomotion of animals and some bio-inspired robots. In this paper we observe that a hip-torque and leg-damping mechanism is fundamental to many legged robots and some animals and determine its affect on locomotion dynamics. We discuss why this hip-torque-and-leg-damping mechanism is not so easily understood. We investigate how hip-torque and leg-damping affect the stability and robustness of locomotion using a mathematical model: First, we extend the canonical spring-loaded-inverted-pendulum model to include constant hip torque and leg damping proportional to leg length speed. Then, we calculate the stability and robustness of locomotion as a function of increasing levels of torque and damping, starting from zero-the energy conserving and marginally stable special case-to high levels of torque and damping. We find that the stabilizing effects of hip-torque and leg-damping occur in the context of the piecewise-continuous dynamics of legged locomotion, and so linear intuition does not apply. We discover that adding hip torque and leg damping changes the stability of legged locomotion in an unexpected way. When a small amount of torque and damping are added, legged locomotion is initially destabilized. As more torque and damping are added, legged locomotion turns stable and becomes increasingly more stable and more robust the more torque and damping are added. Also, stable locomotion becomes more probable over the biologically-relevant region of the parameter space, indicating greater prediction and explanatory capabilities of the model. These results provide a more clear understanding of the hip-torque-and-leg-damping mechanism of legged locomotion, and extend existing theory of legged locomotion towards a greater understanding of robustly stable locomotion. PMID:22989956

  9. Maneuvers during legged locomotion

    NASA Astrophysics Data System (ADS)

    Jindrich, Devin L.; Qiao, Mu

    2009-06-01

    Maneuverability is essential for locomotion. For animals in the environment, maneuverability is directly related to survival. For humans, maneuvers such as turning are associated with increased risk for injury, either directly through tissue loading or indirectly through destabilization. Consequently, understanding the mechanics and motor control of maneuverability is a critical part of locomotion research. We briefly review the literature on maneuvering during locomotion with a focus on turning in bipeds. Walking turns can use one of several different strategies. Anticipation can be important to adjust kinematics and dynamics for smooth and stable maneuvers. During running, turns may be substantially constrained by the requirement for body orientation to match movement direction at the end of a turn. A simple mathematical model based on the requirement for rotation to match direction can describe leg forces used by bipeds (humans and ostriches). During running turns, both humans and ostriches control body rotation by generating fore-aft forces. However, whereas humans must generate large braking forces to prevent body over-rotation, ostriches do not. For ostriches, generating the lateral forces necessary to change movement direction results in appropriate body rotation. Although ostriches required smaller braking forces due in part to increased rotational inertia relative to body mass, other movement parameters also played a role. Turning performance resulted from the coordinated behavior of an integrated biomechanical system. Results from preliminary experiments on horizontal-plane stabilization support the hypothesis that controlling body rotation is an important aspect of stable maneuvers. In humans, body orientation relative to movement direction is rapidly stabilized during running turns within the minimum of two steps theoretically required to complete analogous maneuvers. During straight running and cutting turns, humans exhibit spring-mass behavior in the

  10. Cardiac Arrest-Induced Global Brain Hypoxia-Ischemia during Development Affects Spontaneous Activity Organization in Rat Sensory and Motor Thalamocortical Circuits during Adulthood

    PubMed Central

    Shoykhet, Michael; Middleton, Jason W.

    2016-01-01

    Normal maturation of sensory information processing in the cortex requires patterned synaptic activity during developmentally regulated critical periods. During early development, spontaneous synaptic activity establishes required patterns of synaptic input, and during later development it influences patterns of sensory experience-dependent neuronal firing. Thalamocortical neurons occupy a critical position in regulating the flow of patterned sensory information from the periphery to the cortex. Abnormal thalamocortical inputs may permanently affect the organization and function of cortical neuronal circuits, especially if they occur during a critical developmental window. We examined the effect of cardiac arrest (CA)-associated global brain hypoxia-ischemia in developing rats on spontaneous and evoked firing of somatosensory thalamocortical neurons and on large-scale correlations in the motor thalamocortical circuit. The mean spontaneous and sensory-evoked firing rate activity and variability were higher in CA injured rats. Furthermore, spontaneous and sensory-evoked activity and variability were correlated in uninjured rats, but not correlated in neurons from CA rats. Abnormal activity patterns of ventroposterior medial nucleus (VPm) neurons persisted into adulthood. Additionally, we found that neurons in the entopeduncular nucleus (EPN) in the basal ganglia had lower firing rates yet had higher variability and higher levels of burst firing after injury. Correlated levels of power in local field potentials (LFPs) between the EPN and the motor cortex (MCx) were also disrupted by injury. Our findings indicate that hypoxic-ischemic injury during development leads to abnormal spontaneous and sensory stimulus-evoked input patterns from thalamus to cortex. Abnormal thalamic inputs likely permanently and detrimentally affect the organization of cortical circuitry and processing of sensory information. Hypoxic-ischemic injury also leads to abnormal single neuron and

  11. Cardiac Arrest-Induced Global Brain Hypoxia-Ischemia during Development Affects Spontaneous Activity Organization in Rat Sensory and Motor Thalamocortical Circuits during Adulthood.

    PubMed

    Shoykhet, Michael; Middleton, Jason W

    2016-01-01

    Normal maturation of sensory information processing in the cortex requires patterned synaptic activity during developmentally regulated critical periods. During early development, spontaneous synaptic activity establishes required patterns of synaptic input, and during later development it influences patterns of sensory experience-dependent neuronal firing. Thalamocortical neurons occupy a critical position in regulating the flow of patterned sensory information from the periphery to the cortex. Abnormal thalamocortical inputs may permanently affect the organization and function of cortical neuronal circuits, especially if they occur during a critical developmental window. We examined the effect of cardiac arrest (CA)-associated global brain hypoxia-ischemia in developing rats on spontaneous and evoked firing of somatosensory thalamocortical neurons and on large-scale correlations in the motor thalamocortical circuit. The mean spontaneous and sensory-evoked firing rate activity and variability were higher in CA injured rats. Furthermore, spontaneous and sensory-evoked activity and variability were correlated in uninjured rats, but not correlated in neurons from CA rats. Abnormal activity patterns of ventroposterior medial nucleus (VPm) neurons persisted into adulthood. Additionally, we found that neurons in the entopeduncular nucleus (EPN) in the basal ganglia had lower firing rates yet had higher variability and higher levels of burst firing after injury. Correlated levels of power in local field potentials (LFPs) between the EPN and the motor cortex (MCx) were also disrupted by injury. Our findings indicate that hypoxic-ischemic injury during development leads to abnormal spontaneous and sensory stimulus-evoked input patterns from thalamus to cortex. Abnormal thalamic inputs likely permanently and detrimentally affect the organization of cortical circuitry and processing of sensory information. Hypoxic-ischemic injury also leads to abnormal single neuron and

  12. Scaling macroscopic aquatic locomotion

    NASA Astrophysics Data System (ADS)

    Gazzola, Mattia; Argentina, Mederic; Mahadevan, Lakshminarayanan

    2014-11-01

    Inertial aquatic swimmers that use undulatory gaits range in length L from a few millimeters to 30 meters, across a wide array of biological taxa. Using elementary hydrodynamic arguments, we uncover a unifying mechanistic principle characterizing their locomotion by deriving a scaling relation that links swimming speed U to body kinematics (tail beat amplitude A and frequency ω) and fluid properties (kinematic viscosity ν). This principle can be simply couched as the power law Re ~ Swα , where Re = UL / ν >> 1 and Sw = ωAL / ν , with α = 4 / 3 for laminar flows, and α = 1 for turbulent flows. Existing data from over 1000 measurements on fish, amphibians, larvae, reptiles, mammals and birds, as well as direct numerical simulations are consistent with our scaling. We interpret our results as the consequence of the convergence of aquatic gaits to the performance limits imposed by hydrodynamics.

  13. Scaling macroscopic aquatic locomotion

    NASA Astrophysics Data System (ADS)

    Gazzola, Mattia; Argentina, Médéric; Mahadevan, L.

    2014-10-01

    Inertial aquatic swimmers that use undulatory gaits range in length L from a few millimetres to 30 metres, across a wide array of biological taxa. Using elementary hydrodynamic arguments, we uncover a unifying mechanistic principle characterizing their locomotion by deriving a scaling relation that links swimming speed U to body kinematics (tail beat amplitude A and frequency ω) and fluid properties (kinematic viscosity ν). This principle can be simply couched as the power law Re ~ Swα, where Re = UL/ν >> 1 and Sw = ωAL/ν, with α = 4/3 for laminar flows, and α = 1 for turbulent flows. Existing data from over 1,000 measurements on fish, amphibians, larvae, reptiles, mammals and birds, as well as direct numerical simulations are consistent with our scaling. We interpret our results as the consequence of the convergence of aquatic gaits to the performance limits imposed by hydrodynamics.

  14. 76 FR 2199 - Locomotive Safety Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... October 19, 2007 (72 FR 59216). FRA continued to utilize the RSAC process to address additional locomotive... to reach consensus on the issues related to remote control locomotives, cab temperature, and... proposals related to remote control locomotives, alerters, and locomotive cab temperature, issues that...

  15. 77 FR 21311 - Locomotive Safety Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-09

    .... Brakes, General E. Locomotive Cab Temperature F. Headlights G. Alerters H. Locomotive Electronics I... a minimum permissible locomotive cab temperature. FRA also independently developed a proposal for... in the NPRM and retains it in this final rule. Locomotive Cab Temperature In 1998, FRA led an...

  16. Multi-modal locomotion: from animal to application.

    PubMed

    Lock, R J; Burgess, S C; Vaidyanathan, R

    2014-03-01

    The majority of robotic vehicles that can be found today are bound to operations within a single media (i.e. land, air or water). This is very rarely the case when considering locomotive capabilities in natural systems. Utility for small robots often reflects the exact same problem domain as small animals, hence providing numerous avenues for biological inspiration. This paper begins to investigate the various modes of locomotion adopted by different genus groups in multiple media as an initial attempt to determine the compromise in ability adopted by the animals when achieving multi-modal locomotion. A review of current biologically inspired multi-modal robots is also presented. The primary aim of this research is to lay the foundation for a generation of vehicles capable of multi-modal locomotion, allowing ambulatory abilities in more than one media, surpassing current capabilities. By identifying and understanding when natural systems use specific locomotion mechanisms, when they opt for disparate mechanisms for each mode of locomotion rather than using a synergized singular mechanism, and how this affects their capability in each medium, similar combinations can be used as inspiration for future multi-modal biologically inspired robotic platforms. PMID:24343102

  17. Kinematic adaptations to tripedal locomotion in dogs.

    PubMed

    Goldner, B; Fuchs, A; Nolte, I; Schilling, N

    2015-05-01

    Limb amputation often represents the only treatment option for canine patients with certain diseases or injuries of the appendicular system. Previous studies have investigated adaptations to tripedal locomotion in dogs but there is a lack of understanding of biomechanical compensatory mechanisms. This study evaluated the kinematic differences between quadrupedal and tripedal locomotion in nine healthy dogs running on a treadmill. The loss of the right pelvic limb was simulated using an Ehmer sling. Kinematic gait analysis included spatio-temporal comparisons of limb, joint and segment angles of the remaining pelvic and both thoracic limbs. The following key parameters were compared between quadrupedal and tripedal conditions: angles at touch-down and lift-off, minimum and maximum joint angles, plus range of motion. Significant differences in angular excursion were identified in several joints of each limb during both stance and swing phases. The most pronounced differences concerned the remaining pelvic limb, followed by the contralateral thoracic limb and, to a lesser degree, the ipsilateral thoracic limb. The thoracic limbs were, in general, more retracted, consistent with pelvic limb unloading and previous observations of bodyweight re-distribution in amputees. Proximal limb segments showed more distinct changes than distal ones. Particularly, the persistently greater anteversion of the pelvis probably affects the axial system. Overall, tripedal locomotion requires concerted kinematic adjustments of both the appendicular and axial systems, and consequently preventive, therapeutic and rehabilitative care of canine amputees should involve the whole musculoskeletal apparatus. PMID:25862392

  18. Affective and somatic aspects of spontaneous and precipitated nicotine withdrawal in C57BL/6J and BALB/cByJ mice

    PubMed Central

    Stoker, Astrid K.; Semenova, Svetlana; Markou, Athina

    2008-01-01

    The aversive aspects of nicotine withdrawal are powerful motivational forces contributing to the tobacco smoking habit. We evaluated measures of affective and somatic aspects of nicotine withdrawal in C57BL/6J and BALB/cByJ mice. Nicotine withdrawal was induced by termination of chronic nicotine delivery through osmotic minipumps or precipitated with the nicotinic acetylcholine receptor (nAChR) antagonists mecamylamine or dihydro-β-erythroidine (DHβE). A rate-independent discrete-trial intracranial self-stimulation threshold procedure was used to assess brain reward function. Anxiety-like behavior and sensorimotor gating were assessed in the light-dark box and prepulse inhibition (PPI) tests, respectively. Acoustic startle response and somatic signs of withdrawal were also evaluated. Spontaneous nicotine withdrawal after 14-day exposure to 10–40 mg/kg/day nicotine induced no alterations in anxiety-like behavior, startle reactivity, PPI, or somatic signs in either strain, and no changes in thresholds in C57BL/6J mice. Extended 28-day exposure to 40 mg/kg/day nicotine induced threshold elevations, increased somatic signs, and anxiety-like behavior 24 h post-nicotine in C57BL/6J mice; thresholds returned to baseline levels by day 4 in nicotine-exposed mice. Mecamylamine or DHβE administration induced threshold elevations in nicotine-exposed C57BL/6J mice compared with saline-exposed mice. In conclusion, administration of relatively high nicotine doses over prolonged periods of time induces both the affective and somatic aspects of spontaneous nicotine withdrawal in the mouse, while exposure to nicotine for shorter periods of time is sufficient for nAChR antagonist-precipitated nicotine withdrawal. The current study is one of the first to demonstrate reward deficits associated with both spontaneous and nAChR antagonist-precipitated nicotine withdrawal in C57BL/6J mice. PMID:18452957

  19. Lung ventilation during treadmill locomotion in a semi-aquatic turtle, Trachemys scripta.

    PubMed

    Landberg, Tobias; Mailhot, Jeffrey D; Brainerd, Elizabeth L

    2009-10-01

    It is reasonable to presume that locomotion should have a mechanical effect on breathing in turtles. The turtle shell is rigid, and when the limbs protract and retract, air in the lungs should be displaced. This expectation was met in a previous study of the green sea turtle, Chelonia mydas; breathing completely ceased during terrestrial locomotion (Jackson and Prange, 1979. J Comp Physiol 134:315-319). In contrast, another study found no direct effect of locomotion on ventilation in the terrestrial box turtle, Terrapene carolina (Landberg et al., 2003. J Exp Biol 206:3391-3404). In this study we measured lung ventilation during treadmill locomotion in a semi-aquatic turtle, the red-eared slider, Trachemys scripta. Sliders breathed almost continuously during locomotion and during brief pauses between locomotor bouts. Tidal volume was relatively small (approximately 1 mL) during locomotion and approximately doubled during pauses. Minute ventilation was, however, not significantly smaller during locomotion because breath frequency was higher than that during the pauses. We found no consistent evidence for phase coupling between breathing and locomotion indicating that sliders do not use locomotor movements to drive breathing. We also found no evidence for a buccal-pump mechanism. Sliders, like box turtles, appear to use abdominal musculature to breathe during locomotion. Thus, locomotion affects lung ventilation differently in the three turtle species studied to date: the terrestrial Te. carolina shows no measurable effect of locomotion on ventilation; the semi-aquatic Tr. scripta breathes with smaller tidal volumes during locomotion; and the highly aquatic C. mydas stops breathing completely during terrestrial locomotion. PMID:18623107

  20. Locomotion in a turbulent world

    NASA Astrophysics Data System (ADS)

    Koehl, M.

    2014-11-01

    When organisms swim or crawl in aquatic habitats, the water through which they travel is usually moving. Therefore, an important part of understanding how aquatic organisms locomote is determining how they interact with the fluctuating turbulent water currents through which they move. The research systems we have been using to address this question are microscopic marine animals swimming in turbulent, wavy water flow or crawling on surfaces in spatially-complex habitats exposed to such flow. Using a combination of field studies, wave-flume experiments, experiments in fluidic devices, and mathematical modeling, we have discovered that small organisms swimming or crawling in turbulent flow are not subjected to steady velocities. The shears, accelerations, and odor concentrations encountered by small swimmers and crawlers fluctuate rapidly, with peaks much higher than mean values. Although microscopic organisms swim slowly relative to ambient water flow, their locomotory behavior in response to the rapidly-fluctuating shears and odors they encounter can affect where they are transported by ambient water movement. Furthermore, the ability of small organisms to walk on surfaces without being dislodged by pulses of rapid flow constrains the microhabitats in which they can forage. Supported by NSF Grant #IOS-0842685.

  1. Legless locomotion in lattices

    NASA Astrophysics Data System (ADS)

    Schiebel, Perrin; Goldman, Daniel I.

    2014-11-01

    Little is known about interactions between an animal body and complex terrestrial terrain like sand and boulders during legless, undulatory travel (e.g. snake locomotion). We study the locomotor performance of Mojave shovel-nosed snakes (Chionactisoccipitalis , ~ 35 cm long) using a simplified model of heterogeneous terrain: symmetric lattices of obstacles. To quantify performance we measure mean forward speed and slip angle, βs, defined as the angle between the instantaneous velocity and tangent vectors at each point on the body. We find that below a critical peg density the presence of granular media results in high speed (~ 60 cm/s), low average slip (βs ~6°) snake performance as compared to movement in the same peg densities on hard ground (~ 25 cm/s and βs ~15°). Above this peg density, performance on granular and hard substrates converges. Speed on granular media decreases with increasing peg density to that of the speed on hard ground, while speed on hard ground remains constant. Conversely, βs on hard ground trends toward that on granular media as obstacle density increases.

  2. Intermittent Hypoxia Affects the Spontaneous Differentiation In Vitro of Human Neutrophils into Long-Lived Giant Phagocytes

    PubMed Central

    Dyugovskaya, Larissa; Berger, Slava; Polyakov, Andrey; Lavie, Peretz; Lavie, Lena

    2016-01-01

    Previously we identified, for the first time, a new small-size subset of neutrophil-derived giant phagocytes (Gϕ) which spontaneously develop in vitro without additional growth factors or cytokines. Gϕ are CD66b+/CD63+/MPO+/LC3B+ and are characterized by extended lifespan, large phagolysosomes, active phagocytosis, and reactive oxygen species (ROS) production, and autophagy largely controls their formation. Hypoxia, and particularly hypoxia/reoxygenation, is a prominent feature of many pathological processes. Herein we investigated Gϕ formation by applying various hypoxic conditions. Chronic intermittent hypoxia (IH) (29 cycles/day for 5 days) completely abolished Gϕ formation, while acute IH had dose-dependent effects. Exposure to 24 h (56 IH cycles) decreased their size, yield, phagocytic ability, autophagy, mitophagy, and gp91-phox/p22-phox expression, whereas under 24 h sustained hypoxia (SH) the size and expression of LC3B and gp91-phox/p22-phox resembled Gϕ formed in normoxia. Diphenyl iodide (DPI), a NADPH oxidase inhibitor, as well as the PI3K/Akt and autophagy inhibitor LY294002 abolished Gϕ formation at all oxygen conditions. However, the potent antioxidant, N-acetylcysteine (NAC) abrogated the effects of IH by inducing large CD66b+/LC3B+ Gϕ and increased both NADPH oxidase expression and phagocytosis. These findings suggest that NADPH oxidase, autophagy, and the PI3K/Akt pathway are involved in Gϕ development. PMID:26635914

  3. Loss of Signal Transduction and Inhibition of Lymphocyte Locomotion in a Ground-Based Model of Microgravity

    NASA Technical Reports Server (NTRS)

    Sundaresan, Alamelu; Risin, Diana; Pellis, Neal R.

    1999-01-01

    Inflammatory adherence to, and locomotion through the interstitium is an important component of the immune response. Conditions such as true gravity (TG) and modeled microgravity (MMG) severely inhibit lymphocyte locomotion in vitro through gelled Type I collagen (Pellis et al., 1994, 1997). We used the rotating-wall vessel bioreactor (RWV) as a prototype for modeled microgravity. After observing that lymphocyte locomotion was severely affected in modeled microgravity, we found that polyclonal activation of lymphocytes before exposure to modeled microgravity reversed the locomotion inhibition. Phorbol myristate acetate (PMA) treatment of normal peripheral blood lymphocytes, after exposure to modeled microgravity, restored lymphocyte locomotion by 84%. Calcium ionophore had no effect on modeled microgravity-exposed lymphocytes. Therefore, the signal pathways involving calcium may not be affected by modeled microgravity. However, direct activation of Protein Kinase C (PKC) with PMA was effective in restoring locomotion in modeled microgravity almost comparable to normal levels in lymphocytes cultured in static T flasks. Thus, events either at the level of PKC or upstream are affected by modeled microgravity. Treatment of lymphocytes with mitomycin C prior to exposure to modeled microgravity, followed by PMA, restored locomotion to the same extent as nonmitomycin C-treated lymphocytes exposed to modeled microgravity (80-85%). Therefore 1) new DNA synthesis is not necessary to restore locomotion and 2) traditional activation and locomotion share common pathways up to PKC. Thereafter the signals diverge. Furthermore PMA added immediately before or after initiation of modeled microgravity prevents the loss of lymphocyte locomotion.

  4. Methylmercury differentially affects GABAA receptor-mediated spontaneous IPSCs in Purkinje and granule cells of rat cerebellar slices

    PubMed Central

    Yuan, Yukun; Atchison, William D

    2003-01-01

    Using whole-cell recording techniques we compared effects of the environmental cerebellar neurotoxicant methylmercury (MeHg) on spontaneous IPSCs (sIPSCs) of both Purkinje and granule cells in cerebellar slices of the rat. In Purkinje cells, bath application of 10, 20 or 100 μM MeHg initially increased then suppressed the frequency of sIPSCs to zero. In granule cells, the initial increase in frequency was not observed in ≈50 % of cells examined, but suppression of sIPSCs by MeHg occurred in every cell tested. For both cells, time to onset of effects of MeHg was inversely related to the concentration; moreover, the pattern of changes in mIPSCs induced by MeHg in the presence of tetrodotoxin was similar to that in sIPSCs. For each concentration of MeHg, it took 2–3 times longer to block sIPSCs in Purkinje cells than it did in granule cells. MeHg also initially increased then decreased amplitudes of sIPSCs to block in both cells; again the response was more variable in granule cells. In most Purkinje and some granule cells, MeHg induced a giant, slow inward current during the late stages of exposure. Appearance of this current appeared to be MeHg concentration dependent, and the direction of current flow was reversed by changing the holding potentials. Reduction of the [Cl−] in the internal solution caused inwardly directed, but not outwardly directed giant currents to disappear, suggesting that this current is a Cl−-mediated response. However, bicuculline and picrotoxin failed to block it. MeHg apparently acts at both presynaptic and postsynaptic sites to alter GABAA receptor-mediated inhibitory synaptic transmission. GABAA receptors in granule cells appear to be more sensitive to block by MeHg than are those in Purkinje cells, although the general patterns of effects on the two cells are similar. PMID:12879869

  5. Optimism and spontaneous self-affirmation are associated with lower likelihood of cognitive impairment and greater positive affect among cancer survivors

    PubMed Central

    Taber, Jennifer M.; Klein, William M. P.; Ferrer, Rebecca A.; Kent, Erin E.; Harris, Peter R.

    2016-01-01

    Background Optimism and self-affirmation promote adaptive coping, goal achievement, and better health. Purpose To examine the associations of optimism and spontaneous self-affirmation (SSA) with physical, mental, and cognitive health and information seeking among cancer survivors. Methods Cancer survivors (n=326) completed the Health Information National Trends Survey 2013, a national survey of U.S. adults. Participants reported optimism, SSA, cognitive and physical impairment, affect, health status, and information seeking. Results Participants higher in optimism reported better health on nearly all indices examined, even when controlling for SSA. Participants higher in SSA reported lower likelihood of cognitive impairment, greater happiness and hopefulness, and greater likelihood of cancer information seeking. SSA remained significantly associated with greater hopefulness and cancer information seeking when controlling for optimism. Conclusions Optimism and SSA may be associated with beneficial health-related outcomes among cancer survivors. Given the demonstrated malleability of self-affirmation, these findings represent important avenues for future research. PMID:26497697

  6. Descending Command Neurons in the Brainstem that Halt Locomotion.

    PubMed

    Bouvier, Julien; Caggiano, Vittorio; Leiras, Roberto; Caldeira, Vanessa; Bellardita, Carmelo; Balueva, Kira; Fuchs, Andrea; Kiehn, Ole

    2015-11-19

    The episodic nature of locomotion is thought to be controlled by descending inputs from the brainstem. Most studies have largely attributed this control to initiating excitatory signals, but little is known about putative commands that may specifically determine locomotor offset. To link identifiable brainstem populations to a potential locomotor stop signal, we used developmental genetics and considered a discrete neuronal population in the reticular formation: the V2a neurons. We find that those neurons constitute a major excitatory pathway to locomotor areas of the ventral spinal cord. Selective activation of V2a neurons of the rostral medulla stops ongoing locomotor activity, owing to an inhibition of premotor locomotor networks in the spinal cord. Moreover, inactivation of such neurons decreases spontaneous stopping in vivo. Therefore, the V2a "stop neurons" represent a glutamatergic descending pathway that favors immobility and may thus help control the episodic nature of locomotion. PMID:26590422

  7. The first observation of seasonal affective disorder symptoms in Rhesus macaque.

    PubMed

    Qin, Dongdong; Chu, Xunxun; Feng, Xiaoli; Li, Zhifei; Yang, Shangchuan; Lü, Longbao; Yang, Qing; Pan, Lei; Yin, Yong; Li, Jiali; Xu, Lin; Chen, Lin; Hu, Xintian

    2015-10-01

    Diurnal animals are a better model for seasonal affective disorder (SAD) than nocturnal ones. Previous work with diurnal rodents demonstrated that short photoperiod conditions brought about depression-like behavior. However, rodents are at a large phylogenetic distance from humans. In contrast, nonhuman primates are closely similar to humans, making them an excellent candidate for SAD model. This study made the first attempt to develop SAD in rhesus macaque (Macaca mulatta) and it was found that short photoperiod conditions could lead monkeys to display depressive-like huddling behavior, less spontaneous locomotion, as well as less reactive locomotion. In addition to these depression-related behavioral changes, the physiological abnormalities that occur in patients with SAD, such as weight loss, anhedonia and hypercortisolism, were also observed in those SAD monkeys. Moreover, antidepressant treatment could reverse all of the depression-related symptoms, including depressive-like huddling behavior, less spontaneous locomotion, less reactive locomotion, weight loss, anhedonia and hypercortisolism. For the first time, this study observed the SAD symptoms in rhesus macaque, which would provide an important platform for the understanding of the etiology of SAD as well as developing novel therapeutic interventions in the future. PMID:26164484

  8. Histological Lesions and Cellular Response in the Skin of Alpine Chamois (Rupicapra r. rupicapra) Spontaneously Affected by Sarcoptic Mange

    PubMed Central

    Salvadori, Claudia; Lazzarotti, Camilla; Trogu, Tiziana; Lanfranchi, Paolo

    2016-01-01

    Population dynamics of chamois (genus Rupicapra, subfamily Caprinae) can be influenced by infectious diseases epizootics, of which sarcoptic mange is probably the most severe in the Alpine chamois (Rupicapra rupicapra rupicapra). In this study, skin lesions and cellular inflammatory infiltrates were characterized in 44 Alpine chamois affected by sarcoptic mange. Dermal cellular responses were evaluated in comparison with chamois affected by trombiculosis and controls. In both sarcoptic mange and trombiculosis, a significantly increase of eosinophils, mast cells, T and B lymphocytes, and macrophages was detected. Moreover, in sarcoptic mange significant higher numbers of T lymphocytes and macrophages compared to trombiculosis were observed. Lesions in sarcoptic mange were classified in three grades, according to crusts thickness, correlated with mite counts. Grade 3 represented the most severe form with crust thickness more than 3.5 mm, high number of mites, and severe parakeratosis with diffuse bacteria. Evidence of immediate and delayed hypersensitivity was detected in all three forms associated with diffuse severe epidermal hyperplasia. In grade 3, a significant increase of B lymphocytes was evident compared to grades 1 and 2, while eosinophil counts were significantly higher than in grade 1, but lower than in grade 2 lesions. An involvement of nonprotective Th2 immune response could in part account for severe lesions of grade 3. PMID:27403422

  9. Mutations in the 3c and 7b genes of feline coronavirus in spontaneously affected FIP cats.

    PubMed

    Borschensky, C M; Reinacher, M

    2014-10-01

    Feline infectious peritonitis (FIP) is the most frequent lethal infectious disease in cats. However, understanding of FIP pathogenesis is still incomplete. Mutations in the ORF 3c/ORF 7b genes are proposed to play a role in the occurrence of the fatal FIPV biotype. Here, we investigated 282 tissue specimens from 28 cats that succumbed to FIP. Within one cat, viral sequences from different organs were similar or identical, whereas greater discrepancies were found comparing sequences from various cats. Eleven of the cats exhibited deletions in the 3c gene, resulting in truncated amino acid sequences. The 7b gene was affected by deletions only in one cat. In three of the FIP cats, coronavirus isolates with both intact 3c genes as well as 7b genes of full length could also be detected. Thus, deletions or stop codons in the 3c sequence seem to be a frequent but not compelling feature of FIPVs. PMID:25128417

  10. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive horn. 229.129 Section 229.129 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Cabs and Cab Equipment § 229.129 Locomotive horn. (a) Each...

  11. Dynamic affordances in embodied interactive systems: the role of display and mode of locomotion.

    PubMed

    Grechkin, Timofey Y; Plumert, Jodie M; Kearney, Joseph K

    2014-04-01

    We investigated how the properties of interactive virtual reality systems affect user behavior in full-body embodied interactions. Our experiment compared four interactive virtual reality systems using different display types (CAVE vs. HMD) and modes of locomotion (walking vs. joystick). Participants performed a perceptual-motor coordination task, in which they had to choose among a series of opportunities to pass through a gate that cycled open and closed and then board a moving train. Mode of locomotion, but not type of display, affected how participants chose opportunities for action. Both mode of locomotion and display affected performance when participants acted on their choices. We conclude that technological properties of virtual reality system (both display and mode of locomotion) significantly affected opportunities for action available in the environment (affordances) and discuss implications for design and practical applications of immersive interactive systems. PMID:24650987

  12. Central Pattern Generator for Locomotion: Anatomical, Physiological, and Pathophysiological Considerations

    PubMed Central

    Guertin, Pierre A.

    2013-01-01

    This article provides a perspective on major innovations over the past century in research on the spinal cord and, specifically, on specialized spinal circuits involved in the control of rhythmic locomotor pattern generation and modulation. Pioneers such as Charles Sherrington and Thomas Graham Brown have conducted experiments in the early twentieth century that changed our views of the neural control of locomotion. Their seminal work supported subsequently by several decades of evidence has led to the conclusion that walking, flying, and swimming are largely controlled by a network of spinal neurons generally referred to as the central pattern generator (CPG) for locomotion. It has been subsequently demonstrated across all vertebrate species examined, from lampreys to humans, that this CPG is capable, under some conditions, to self-produce, even in absence of descending or peripheral inputs, basic rhythmic, and coordinated locomotor movements. Recent evidence suggests, in turn, that plasticity changes of some CPG elements may contribute to the development of specific pathophysiological conditions associated with impaired locomotion or spontaneous locomotor-like movements. This article constitutes a comprehensive review summarizing key findings on the CPG as well as on its potential role in Restless Leg Syndrome, Periodic Leg Movement, and Alternating Leg Muscle Activation. Special attention will be paid to the role of the CPG in a recently identified, and uniquely different neurological disorder, called the Uner Tan Syndrome. PMID:23403923

  13. Venous cerebral blood volume increase during voluntary locomotion reflects cardiovascular changes.

    PubMed

    Huo, Bing-Xing; Greene, Stephanie E; Drew, Patrick J

    2015-09-01

    Understanding how changes in the cardiovascular system contribute to cerebral blood flow (CBF) and volume (CBV) increases is critical for interpreting hemodynamic signals. Here we investigated how systemic cardiovascular changes affect the cortical hemodynamic response during voluntary locomotion. In the mouse, voluntary locomotion drives an increase in cortical CBF and arterial CBV that is localized to the forelimb/hindlimb representation in the somatosensory cortex, as well as a diffuse venous CBV increase. To determine if the heart rate increases that accompany locomotion contribute to locomotion-induced CBV and CBF increases, we occluded heart rate increases with the muscarinic cholinergic receptor antagonist glycopyrrolate, and reduced heart rate with the β1-adrenergic receptor antagonist atenolol. We quantified the effects of these cardiovascular manipulations on CBV and CBF dynamics by comparing the hemodynamic response functions (HRF) to locomotion across these conditions. Neither the CBF HRF nor the arterial component of the CBV HRF was significantly affected by pharmacological disruption of the heart rate. In contrast, the amplitude and spatial extent of the venous component of the CBV HRF were decreased by atenolol. These results suggest that the increase in venous CBV during locomotion was partially driven by peripheral cardiovascular changes, whereas CBF and arterial CBV increases associated with locomotion reflect central processes. PMID:26057593

  14. [Locomotion disturbances in Huntington's disease].

    PubMed

    Delval, A; Krystkowiak, P

    2010-02-01

    In Huntington's disease (HD), perturbed locomotion occurs early in the course of the disease and presents numerous clinical features. The gait disorders in HD might best be defined as a timing disorder; however, hypokinesia (i.e. a decrease in stride length) also plays an important role in disturbed locomotion as HD progresses. Gait impairments are particularly important because they lead to an increased risk of falls. Falls risk factors and consequences depend on the stage of the disease. A satisfactory therapeutic strategy for gait impairments is a serious challenge: the use of a metronome during gait in HD patients does not effectively improve their gait. Attention deficits in HD may be a major determinant of this failure. The effect of antichoreic medications on gait is still controversial because of the absence of specific evaluation of these medications on gait disturbances. PMID:19604530

  15. The K-Ras 4A isoform promotes apoptosis but does not affect either lifespan or spontaneous tumor incidence in aging mice

    SciTech Connect

    Plowman, Sarah J.; Arends, Mark J.; Brownstein, David G.; Luo Feijun; Devenney, Paul S.; Rose, Lorraine; Ritchie, Ann-Marie; Berry, Rachel L.; Harrison, David J.; Hooper, Martin L.; Patek, Charles E. . E-mail: Charles.Patek@ed.ac.uk

    2006-01-01

    Ras proteins function as molecular switches in signal transduction pathways, and, here, we examined the effects of the K-ras4A and 4B splice variants on cell function by comparing wild-type embryonic stem (ES) cells with K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} (exon 4A knock-out) ES cells which express K-ras4B only and K-ras {sup -/-} (exons 1-3 knock-out) ES cells which express neither splice variant, and intestinal epithelium from wild-type and K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} mice. RT-qPCR analysis found that K-ras4B expression was reduced in K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} ES cells but unaffected in small intestine. K-Ras deficiency did not affect ES cell growth, and K-Ras4A deficiency did not affect intestinal epithelial proliferation. K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} and K-ras {sup -/-} ES cells showed a reduced capacity for differentiation following LIF withdrawal, and K-ras {sup -/-} cells were least differentiated. K-Ras4A deficiency inhibited etoposide-induced apoptosis in ES cells and intestinal epithelial cells. However, K-ras {sup tm{delta}}{sup 4A/tm{delta}}{sup 4A} ES cells were more resistant to etoposide-induced apoptosis than K-ras {sup -/-} cells. The results indicate that (1) K-Ras4A promotes apoptosis while K-Ras4B inhibits it, and (2) K-Ras4B, and possibly K-Ras4A, promotes differentiation. The findings raise the possibility that alteration of the K-Ras4A/4B isoform ratio modulates tumorigenesis by differentially affecting stem cell survival and/or differentiation. However, K-Ras4A deficiency did not affect life expectancy or spontaneous overall tumor incidence in aging mice.

  16. Stability of underwater periodic locomotion

    NASA Astrophysics Data System (ADS)

    Jing, Fangxu; Kanso, Eva

    2013-07-01

    Most aquatic vertebrates swim by lateral flapping of their bodies and caudal fins. While much effort has been devoted to understanding the flapping kinematics and its influence on the swimming efficiency, little is known about the stability (or lack of) of periodic swimming. It is believed that stability limits maneuverability and body designs/flapping motions that are adapted for stable swimming are not suitable for high maneuverability and vice versa. In this paper, we consider a simplified model of a planar elliptic body undergoing prescribed periodic heaving and pitching in potential flow. We show that periodic locomotion can be achieved due to the resulting hydrodynamic forces, and its value depends on several parameters including the aspect ratio of the body, the amplitudes and phases of the prescribed flapping.We obtain closedform solutions for the locomotion and efficiency for small flapping amplitudes, and numerical results for finite flapping amplitudes. This efficiency analysis results in optimal parameter values that are in agreement with values reported for some carangiform fish. We then study the stability of the (finite amplitude flapping) periodic locomotion using Floquet theory. We find that stability depends nonlinearly on all parameters. Interesting trends of switching between stable and unstable motions emerge and evolve as we continuously vary the parameter values. This suggests that, for live organisms that control their flapping motion, maneuverability and stability need not be thought of as disjoint properties, rather the organism may manipulate its motion in favor of one or the other depending on the task at hand.

  17. Lunar Balance and Locomotion

    NASA Technical Reports Server (NTRS)

    Paloski, William H.

    2008-01-01

    Balance control and locomotor patterns were altered in Apollo crewmembers on the lunar surface, owing, presumably, to a combination of sensory-motor adaptation during transit and lunar surface operations, decreased environmental affordances associated with the reduced gravity, and restricted joint mobility as well as altered center-of-gravity caused by the EVA pressure suits. Dr. Paloski will discuss these factors, as well as the potential human and mission impacts of falls and malcoordination during planned lunar sortie and outpost missions. Learning objectives: What are the potential impacts of postural instabilities on the lunar surface? CME question: What factors affect balance control and gait stability on the moon? Answer: Sensory-motor adaptation to the lunar environment, reduced mechanical and visual affordances, and altered biomechanics caused by the EVA suit.

  18. Energetics of terrestrial locomotion of the platypus Ornithorhynchus anatinus.

    PubMed

    Fish, F E; Frappell, P B; Baudinette, R V; MacFarlane, P M

    2001-02-01

    The platypus Ornithorhynchus anatinus Shaw displays specializations in its limb structure for swimming that could negatively affect its terrestrial locomotion. Platypuses walked on a treadmill at speeds of 0.19-1.08 m x s(-1). Video recordings were used for gait analysis, and the metabolic rate of terrestrial locomotion was studied by measuring oxygen consumption. Platypuses used walking gaits (duty factor >0.50) with a sprawled stance. To limit any potential interference from the extensive webbing on the forefeet, platypuses walk on their knuckles. Metabolic rate increased linearly over a 2.4-fold range with increasing walking speed in a manner similar to that of terrestrial mammals, but was low as a result of the relatively low standard metabolic rate of this monotreme. The dimensionless cost of transport decreased with increasing speed to a minimum of 0.79. Compared with the cost of transport for swimming, the metabolic cost for terrestrial locomotion was 2.1 times greater. This difference suggests that the platypus may pay a price in terrestrial locomotion by being more aquatically adapted than other semi-aquatic or terrestrial mammals. PMID:11171362

  19. The Effect of Increasing Mass upon Locomotion

    NASA Technical Reports Server (NTRS)

    DeWitt, John; Hagan, Donald

    2007-01-01

    The purpose of this investigation was to determine if increasing body mass while maintaining bodyweight would affect ground reaction forces and joint kinetics during walking and running. It was hypothesized that performing gait with increased mass while maintaining body weight would result in greater ground reaction forces, and would affect the net joint torques and work at the ankle, knee and hip when compared to gait with normal mass and bodyweight. Vertical ground reaction force was measured for ten subjects (5M/5F) during walking (1.34 m/s) and running (3.13 m/s) on a treadmill. Subjects completed one minute of locomotion at normal mass and bodyweight and at four added mass (AM) conditions (10%, 20%, 30% and 40% of body mass) in random order. Three-dimensional joint position data were collected via videography. Walking and running were analyzed separately. The addition of mass resulted in several effects. Peak impact forces and loading rates increased during walking, but decreased during running. Peak propulsive forces decreased during walking and did not change during running. Stride time increased and hip extensor angular impulse and positive work increased as mass was added for both styles of locomotion. Work increased at a greater rate during running than walking. The adaptations to additional mass that occur during walking are different than during running. Increasing mass during exercise in microgravity may be beneficial to increasing ground reaction forces during walking and strengthening hip musculature during both walking and running. Future study in true microgravity is required to determine if the adaptations found would be similar in a weightless environment.

  20. 49 CFR 229.209 - Alternative locomotive crashworthiness designs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Alternative locomotive crashworthiness designs... Locomotive Crashworthiness Design Requirements § 229.209 Alternative locomotive crashworthiness designs. (a... locomotive crashworthiness designs which are not consistent with any FRA-approved locomotive...

  1. Spontaneous Fission

    DOE R&D Accomplishments Database

    Segre, Emilio

    1950-11-22

    The first attempt to discover spontaneous fission in uranium was made by [Willard] Libby, who, however, failed to detect it on account of the smallness of effect. In 1940, [K. A.] Petrzhak and [G. N.] Flerov, using more sensitive methods, discovered spontaneous fission in uranium and gave some rough estimates of the spontaneous fission decay constant of this substance. Subsequently, extensive experimental work on the subject has been performed by several investigators and will be quoted in the various sections. [N.] Bohr and [A.] Wheeler have given a theory of the effect based on the usual ideas of penetration of potential barriers. On this project spontaneous fission has been studied for the past several years in an effort to obtain a complete picture of the phenomenon. For this purpose the spontaneous fission decay constants {lambda} have been measured for separated isotopes of the heavy elements wherever possible. Moreover, the number {nu} of neutrons emitted per fission has been measured wherever feasible, and other characteristics of the spontaneous fission process have been studied. This report summarizes the spontaneous fission work done at Los Alamos up to January 1, 1945. A chronological record of the work is contained in the Los Alamos monthly reports.

  2. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were... performance or operability of the locomotive or locomotive engine. (6) A description of the adverse effects, if any, that such nonconformity would have on the performance or operability of the locomotive...

  3. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were... performance or operability of the locomotive or locomotive engine. (6) A description of the adverse effects, if any, that such nonconformity would have on the performance or operability of the locomotive...

  4. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Forward end structure of locomotives, including... SAFETY STANDARDS Specific Requirements for Tier I Passenger Equipment § 238.209 Forward end structure of locomotives, including cab cars and MU locomotives. (a)(1) The skin covering the forward-facing end of...

  5. Lung ventilation during treadmill locomotion in a terrestrial turtle, Terrapene carolina.

    PubMed

    Landberg, Tobias; Mailhot, Jeffrey D; Brainerd, Elizabeth L

    2003-10-01

    The limb girdles and lungs of turtles are both located within the bony shell, and therefore limb movements during locomotion could affect breathing performance. A mechanical conflict between locomotion and lung ventilation has been reported in adult green sea turtles, Chelonia mydas, in which breathing stops during terrestrial locomotion and resumes during pauses between bouts of locomotion. We measured lung ventilation during treadmill locomotion using pneumotach masks in three individual Terrapene carolina (mass 304-416 g) and found no consistent mechanical effects of locomotion on breathing performance. Relatively small tidal volumes (2.2+/-1.4 ml breath(-1); mean +/- S.D., N=3 individuals) coupled with high breath frequencies (36.6+/-26.4 breaths min(-1); mean +/- S.D., N=3 individuals) during locomotion yield mass-specific minute volumes that are higher than any previously reported for turtles (264+/-64 ml min kg(-1); mean +/- S.D., N=3 individuals). Minute volume was higher during locomotion than during recovery from exercise (P<0.01; paired t-test), and tidal volumes measured during locomotion were not significantly different from values measured during brief pauses between locomotor bouts or during recovery from exercise (P>0.05; two-way ANOVA). Since locomotion does not appear to conflict with breathing performance, the mechanism of lung ventilation must be either independent of, or coupled to, the stride cycle. The timing of peak airflow from breaths occurring during locomotion does not show any fixed phase relationship with the stride cycle. Additionally, the peak values of inhalatory and exhalatory airflow rates do not differ consistently with respect to the stride cycle. Together, these data indicate that T. carolina is not using respiratory-locomotor coupling and limb and girdle movements do not contribute to lung ventilation during locomotion. X-ray video recordings indicate that lung ventilation is achieved via bilateral activity of the transverse

  6. Changes in gravity inhibit lymphocyte locomotion through type I collagen

    NASA Technical Reports Server (NTRS)

    Pellis, N. R.; Goodwin, T. J.; Risin, D.; McIntyre, B. W.; Pizzini, R. P.; Cooper, D.; Baker, T. L.; Spaulding, G. F.

    1997-01-01

    Immunity relies on the circulation of lymphocytes through many different tissues including blood vessels, lymphatic channels, and lymphoid organs. The ability of lymphocytes to traverse the interstitium in both nonlymphoid and lymphoid tissues can be determined in vitro by assaying their capacity to locomote through Type I collagen. In an attempt to characterize potential causes of microgravity-induced immunosuppression, we investigated the effects of simulated microgravity on human lymphocyte function in vitro using a specialized rotating-wall vessel culture system developed at the Johnson Space Center. This very low shear culture system randomizes gravitational vectors and provides an in vitro approximation of microgravity. In the randomized gravity of the rotating-wall vessel culture system, peripheral blood lymphocytes did not locomote through Type I collagen, whereas static cultures supported normal movement. Although cells remained viable during the entire culture period, peripheral blood lymphocytes transferred to unit gravity (static culture) after 6 h in the rotating-wall vessel culture system were slow to recover and locomote into collagen matrix. After 72 h in the rotating-wall vessel culture system and an additional 72 h in static culture, peripheral blood lymphocytes did not recover their ability to locomote. Loss of locomotory activity in rotating-wall vessel cultures appears to be related to changes in the activation state of the lymphocytes and the expression of adhesion molecules. Culture in the rotating-wall vessel system blunted the ability of peripheral blood lymphocytes to respond to polyclonal activation with phytohemagglutinin. Locomotory response remained intact when peripheral blood lymphocytes were activated by anti-CD3 antibody and interleukin-2 prior to introduction into the rotating-wall vessel culture system. Thus, in addition to the systemic stress factors that may affect immunity, isolated lymphocytes respond to gravitational changes

  7. Biomechanics of locomotion in subgravity.

    PubMed

    Margaria, R

    1973-01-01

    The speed of walking or running on the moon as compared with earth is appreciably reduced, in spite of mechanisms of compensation taking place such a forward leaning of the body and an increase of the horizontal component of the push of the foot on the ground. However on the moon the same speed of locomotion as on earth can be reached by shifting to a different mechanism of locomotion, i. e. progression by jumps, which becomes possible on the moon because of the reduction of the body weight. The energy cost of locomotion is certainly less on the moon than on earth, about 1/6. Were the subject not restrained by the space suit, progression by jumps at 20 km hr-1 on the moon would cost no more than 10 ml kg-1 min-1 of oxygen, the same as walking on earth at 6 km hr-1. Maximal acceleration of the body as in sprinting, or deceleration as in stopping, attains much higher values on earth than on the moon. While sprinting on earth may involve the maximal muscular power, sprinting or progressing at the highest speed on the moon involves only a fraction of the maximal power, mainly because of the reduced maximal frequency of the steps (or jumps). The maximal height of the jump on both feet on the moon could attain 4 m in the unrestricted subject. An analysis is wanted on the restriction of the movements brought about by the space suit and on the energy cost of progression. PMID:12523382

  8. Dopamine autoreceptors and the effects of drugs on locomotion and dopamine synthesis.

    PubMed Central

    Brown, F.; Campbell, W.; Mitchell, P. J.; Randall, K.

    1985-01-01

    Criteria for distinguishing dopamine autoreceptor agonism from other mechanisms of inhibiting locomotion were examined, together with the relationship between inhibition of locomotion and dopamine synthesis. ED50 potencies to inhibit locomotion of mice were established for drugs from a number of categories. Spiperone 0.02 mg kg-1 significantly (P less than 0.05) reversed inhibition of locomotion by known dopamine agonists but not that by the other types of drug. Idazoxan antagonized inhibition of locomotion due to alpha 2-agonists but not dopamine agonists. RU 24926 (N-propyl-N,N-di[2-(3-hydroxyphenyl)ethyl]amine) was antagonized by both spiperone and idazoxan. Only for dopamine agonists was there good correlation (r = 0.97) between potencies to inhibit locomotion in mice and L-dihydroxyphenylalanine (L-DOPA) accumulation in the nucleus accumbens of rats treated with gamma-butyrolactone and 3-hydroxybenzylhydrazine. The specific dopamine D1-agonist, SK&F 38393 (2,3,4,5-tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine), was inactive in both tests at doses up to 10 mg kg-1. The mixed dopamine agonist/antagonist, (-)-3-(3-hydroxyphenyl)-N-propylpiperidine, commonly known as (-)-3-PPP, acted as a dopamine agonist in both tests but inhibited locomotion more potently than L-DOPA accumulation. The inhibitory effects of dopamine agonists on locomotion were not prevented by alpha-methyl-p-tyrosine pretreatment. The data suggest that spiperone-reversible inhibition of locomotion in mice is a good criterion for dopamine autoreceptor agonists. The receptors involved are affected by low doses of both dopamine agonists and antagonists and seem similar to those involved in the autoreceptor mediated inhibition of dopamine synthesis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:4005487

  9. Diencephalic regulation of respiration and arterial pressure during actual and fictive locomotion in cat.

    PubMed

    Millhorn, D E; Eldridge, F L; Waldrop, T G; Kiley, J P

    1987-10-01

    The purpose of this study was to examine by experimentation the hypothesis that the respiratory and circulatory responses during exercise are attributable to command signals that emanate from the suprapontine brain. We studied the relations between locomotion (exercise) and phrenic nerve activity and arterial pressure in cats that walked or ran on a treadmill and in animals during fictive locomotion, i.e., locomotor activity in motor nerves to legs. Anesthetized cats with intact brains and unanesthetized decorticated cats were used. All preparations exhibited spontaneous actual and fictive locomotion. Electrical stimulation or microinjection of picrotoxin, a GABA antagonist, of the subthalamic locomotor areas always caused locomotion to develop. Phrenic nerve activity and arterial pressure increased in proportion to the level of locomotor activity despite control or ablation of feedback signals from chemoreceptors and vagal receptors. Similar relations were measured during fictive locomotion despite the absence of muscular contraction and limb movement and the lack of change in metabolic rate. These findings provide experimental support for the central command hypothesis for the genesis of the respiratory hyperpnea and increased cardiovascular function that occur during exercise. We believe that the command signals emanate from the subthalamic locomotor area of the diencephalon. PMID:3652403

  10. Functions of Intermittent Locomotion in Mustached Tamarins (Saguinus mystax)

    PubMed Central

    Heymann, Eckhard W.

    2010-01-01

    Many animals interrupt their moving with brief pauses, which appear to serve several different functions. We examined the function of such intermittent locomotion in wild living mustached tamarins (Saguinus mystax), small arboreal New World primates that form mixed-species groups with saddleback tamarins (Saguinus fuscicollis). We investigated how different environmental and social factors affect pausing during locomotion and used these data to infer the function of this behavior. As measures of intermittent locomotion, we used percentage of time spent pausing and pause rate. We considered 3 possible functions that are not mutually exclusive: increased endurance, route planning, and antipredator vigilance. Mustached tamarins spent on average (mean ± SE) 55.1 ± 1.0% of time pausing, which makes effective resource exploitation more time consuming and needs to be outweighed by correspondingly large benefits. Percentage of time spent pausing decreased in larger mixed-species groups vs. smaller mixed-species groups and decreased with height and in monkeys carrying infants. It was not affected by sex, age, spatial arrangement, or single-species group size. Pause rate increased in individuals traveling independently compared to those traveling in file, but was not affected by other factors. The group size effect in mixed-species groups lends support to the notion that pausing during locomotion is an antipredator tactic that can be reduced in the increased safety of larger groups, but other results suggest that additional functions, particularly route planning, are also of great importance. Benefits in terms of predator confusion and group movement coordination are also likely to play a role and remain a topic for further research. PMID:20949115

  11. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  12. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  13. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  14. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  15. 76 FR 8699 - Locomotive Safety Standards; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... NPRM related to locomotive safety standards. See 76 FR 2200. The NPRM established a public docket to... the proposed rule published January 12, 2011, at 76 FR 2200, remains March 14, 2011. FOR FURTHER... Federal Railroad Administration 49 CFR Parts 229 and 238 RIN 2130-AC16 Locomotive Safety...

  16. 30 CFR 56.6203 - Locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Locomotives. 56.6203 Section 56.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6203 Locomotives. Explosive material shall not...

  17. 30 CFR 56.6203 - Locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Locomotives. 56.6203 Section 56.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6203 Locomotives. Explosive material shall not...

  18. 30 CFR 56.6203 - Locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Locomotives. 56.6203 Section 56.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6203 Locomotives. Explosive material shall not...

  19. 30 CFR 56.6203 - Locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Locomotives. 56.6203 Section 56.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6203 Locomotives. Explosive material shall not...

  20. 30 CFR 56.6203 - Locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Locomotives. 56.6203 Section 56.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6203 Locomotives. Explosive material shall not...

  1. Novel locomotion via biological inspiration

    NASA Astrophysics Data System (ADS)

    Quinn, Roger D.; Boxerbaum, Alexander; Palmer, Luther; Chiel, Hillel; Diller, Eric; Hunt, Alexander; Bachmann, Richard

    2011-05-01

    Animal behavioral, physiological and neurobiological studies are providing a wealth of inspirational data for robot design and control. Several very different biologically inspired mobile robots will be reviewed. A robot called DIGbot is being developed that moves independent of the direction of gravity using Distributed Inward Gripping (DIG) as a rapid and robust attachment mechanism observed in climbing animals. DIGbot is an 18 degree of freedom hexapod with onboard power and control systems. Passive compliance in its feet, which is inspired by the flexible tarsus of the cockroach, increases the robustness of the adhesion strategy and enables DIGbot to execute large steps and stationary turns while walking on mesh screens. A Whegs™ robot, inspired by insect locomotion principles, is being developed that can be rapidly reconfigured between tracks and wheel-legs and carry GeoSystems Zipper Mast. The mechanisms that cause it to passively change its gait on irregular terrain have been integrated into its hubs for a compact and modular design. The robot is designed to move smoothly on moderately rugged terrain using its tracks and run on irregular terrain and stairs using its wheel-legs. We are also developing soft bodied robots that use peristalsis, the same method of locomotion earthworms use. We present a technique of using a braided mesh exterior to produce fluid waves of motion along the body of the robot that increase the robot's speed relative to previous designs. The concept is highly scalable, for endoscopes to water, oil or gas line inspection.

  2. Simulation of a Hybrid Locomotion Robot Vehicle

    NASA Astrophysics Data System (ADS)

    Aarnio, P.

    2002-10-01

    This study describes a simulation process of a mobile robot. The focus is in kinematic and dynamic behavior simulations of hybrid locomotion robot vehicles. This research is motivated by the development needs of the WorkPartner field service robot. The whole robot system consists of a mobile platform and a two-hand manipulator. The robot platform, called Hybtor, is a hybrid locomotion robot capable of walking and driving by wheels as well as combining these two locomotion modes. This study describes first the general problems and their solutions in the dynamic simulation of mobile robots. A kinematic and dynamic virtual model of the Hybtor robot was built and simulations were carried out using one commercial simulation tool. Walking, wheel driven and rolking mode locomotion, which is a special hybrid locomotion style, has been simulated and analyzed. Position and force control issues during obstacle overrun and climbing were also studied.

  3. Spinal circuitry of sensorimotor control of locomotion

    PubMed Central

    McCrea, David A

    2001-01-01

    During locomotion many segmental hindlimb reflex pathways serve not only to regulate the excitability of local groups of motoneurones, but also to control the basic operation of the central pattern-generating circuitry responsible for locomotion. This is accomplished through a reorganization of reflexes that includes the suppression of reflex pathways operating at rest and the recruitment during locomotion of previously unrecognized types of spinal interneurones. In addition presynaptic inhibition of transmission from segmental afferents serves to regulate the gain of segmental reflexes and may contribute to the selection of particular reflex pathways during locomotion. The fictive locomotion preparation in adult decerebrate cats has proved to be an important tool in understanding reflex pathway reorganization. Further identification of the spinal interneurones involved in locomotor-dependent reflexes will contribute to our understanding not only of reflex pathway organization but also of the organization of the mammalian central pattern generator. PMID:11351011

  4. [Spontaneous mediastinal emphysema].

    PubMed

    Svedbrand, Charlotte; Lange, Peter; Nielsen, Klaus

    2016-01-01

    Spontaneous mediastinal emphysema, also known as spontaneous pneumomediastinum, is defined as radiologically detected free air in the mediastinum, without preceding trauma. It is a rare condition, mainly affecting young adults. It can be caused by coughing, strenuous sports or cocaine inhalation, however, 40% are idiopatic. Common symptoms are chest pain and dyspnoea. 75-90% can be diagnosed with a chest X-ray, and 100% with a computed tomography. Treatment is symptomatic and complications are rare, however, pneumothorax and pneumorrachis have been reported. PMID:26750190

  5. Peritonitis - spontaneous

    MedlinePlus

    ... a catheter used in peritoneal dialysis. Antibiotics may control infection in cases of spontaneous peritonitis with liver or kidney disease. Intravenous therapy can treat dehydration . You may need to stay in the hospital so health care providers can rule out conditions ...

  6. Differences in gaze anticipation for locomotion with and without vision.

    PubMed

    Authié, Colas N; Hilt, Pauline M; N'Guyen, Steve; Berthoz, Alain; Bennequin, Daniel

    2015-01-01

    Previous experimental studies have shown a spontaneous anticipation of locomotor trajectory by the head and gaze direction during human locomotion. This anticipatory behavior could serve several functions: an optimal selection of visual information, for instance through landmarks and optic flow, as well as trajectory planning and motor control. This would imply that anticipation remains in darkness but with different characteristics. We asked 10 participants to walk along two predefined complex trajectories (limaçon and figure eight) without any cue on the trajectory to follow. Two visual conditions were used: (i) in light and (ii) in complete darkness with eyes open. The whole body kinematics were recorded by motion capture, along with the participant's right eye movements. We showed that in darkness and in light, horizontal gaze anticipates the orientation of the head which itself anticipates the trajectory direction. However, the horizontal angular anticipation decreases by a half in darkness for both gaze and head. In both visual conditions we observed an eye nystagmus with similar properties (frequency and amplitude). The main difference comes from the fact that in light, there is a shift of the orientations of the eye nystagmus and the head in the direction of the trajectory. These results suggest that a fundamental function of gaze is to represent self motion, stabilize the perception of space during locomotion, and to simulate the future trajectory, regardless of the vision condition. PMID:26106313

  7. Data-driven stochastic modelling of zebrafish locomotion.

    PubMed

    Zienkiewicz, Adam; Barton, David A W; Porfiri, Maurizio; di Bernardo, Mario

    2015-11-01

    In this work, we develop a data-driven modelling framework to reproduce the locomotion of fish in a confined environment. Specifically, we highlight the primary characteristics of the motion of individual zebrafish (Danio rerio), and study how these can be suitably encapsulated within a mathematical framework utilising a limited number of calibrated model parameters. Using data captured from individual zebrafish via automated visual tracking, we develop a model using stochastic differential equations and describe fish as a self propelled particle moving in a plane. Based on recent experimental evidence of the importance of speed regulation in social behaviour, we extend stochastic models of fish locomotion by introducing experimentally-derived processes describing dynamic speed regulation. Salient metrics are defined which are then used to calibrate key parameters of coupled stochastic differential equations, describing both speed and angular speed of swimming fish. The effects of external constraints are also included, based on experimentally observed responses. Understanding the spontaneous dynamics of zebrafish using a bottom-up, purely data-driven approach is expected to yield a modelling framework for quantitative investigation of individual behaviour in the presence of various external constraints or biological assays. PMID:25358499

  8. 49 CFR 238.223 - Locomotive fuel tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Locomotive fuel tanks. 238.223 Section 238.223... Equipment § 238.223 Locomotive fuel tanks. Locomotive fuel tanks shall comply with either the following or....21: (a) External fuel tanks. External locomotive fuel tanks shall comply with the...

  9. 49 CFR 238.223 - Locomotive fuel tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Locomotive fuel tanks. 238.223 Section 238.223... Equipment § 238.223 Locomotive fuel tanks. Locomotive fuel tanks shall comply with either the following or....21: (a) External fuel tanks. External locomotive fuel tanks shall comply with the...

  10. 49 CFR 229.209 - Alternative locomotive crashworthiness designs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Alternative locomotive crashworthiness designs... Locomotive Crashworthiness Design Requirements § 229.209 Alternative locomotive crashworthiness designs. (a... design standard. (b) Petitions for FRA approval of alternative locomotive crashworthiness designs....

  11. 49 CFR 229.209 - Alternative locomotive crashworthiness designs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Alternative locomotive crashworthiness designs... Locomotive Crashworthiness Design Requirements § 229.209 Alternative locomotive crashworthiness designs. (a... design standard. (b) Petitions for FRA approval of alternative locomotive crashworthiness designs....

  12. 49 CFR 229.209 - Alternative locomotive crashworthiness designs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Alternative locomotive crashworthiness designs... Locomotive Crashworthiness Design Requirements § 229.209 Alternative locomotive crashworthiness designs. (a... design standard. (b) Petitions for FRA approval of alternative locomotive crashworthiness designs....

  13. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  14. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  15. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  16. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  17. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  18. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  19. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  20. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  1. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  2. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  3. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Production locomotives and engines. 92... (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Certification Provisions § 92.214 Production locomotives and engines. Any manufacturer or remanufacturer obtaining...

  4. 49 CFR 238.223 - Locomotive fuel tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Locomotive fuel tanks. 238.223 Section 238.223... Equipment § 238.223 Locomotive fuel tanks. Locomotive fuel tanks shall comply with either the following or....21: (a) External fuel tanks. External locomotive fuel tanks shall comply with the...

  5. 40 CFR 1033.652 - Special provisions for exported locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Special Compliance Provisions § 1033.652 Special provisions for exported locomotives. (a) Uncertified locomotives. Locomotives covered by an export exemption under 40 CFR 1068.230 may be introduced into U.S. commerce prior to being exported, but may not...

  6. 40 CFR 1033.652 - Special provisions for exported locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Special Compliance Provisions § 1033.652 Special provisions for exported locomotives. (a) Uncertified locomotives. Locomotives covered by an export exemption under 40 CFR 1068.230 may be introduced into U.S. commerce prior to being exported, but may not...

  7. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Production locomotives and engines. 92... (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Certification Provisions § 92.214 Production locomotives and engines. Any manufacturer or remanufacturer obtaining...

  8. The primate semicircular canal system and locomotion

    PubMed Central

    Spoor, Fred; Garland, Theodore; Krovitz, Gail; Ryan, Timothy M.; Silcox, Mary T.; Walker, Alan

    2007-01-01

    The semicircular canal system of vertebrates helps coordinate body movements, including stabilization of gaze during locomotion. Quantitative phylogenetically informed analysis of the radius of curvature of the three semicircular canals in 91 extant and recently extinct primate species and 119 other mammalian taxa provide support for the hypothesis that canal size varies in relation to the jerkiness of head motion during locomotion. Primate and other mammalian species studied here that are agile and have fast, jerky locomotion have significantly larger canals relative to body mass than those that move more cautiously. PMID:17576932

  9. A quantifiably complete repertoire of C. elegans locomotion

    NASA Astrophysics Data System (ADS)

    Brown, Andre; Schwarz, Roland; Branicky, Robyn; Schafer, William

    2014-03-01

    Visible phenotypes have played a critical role in understanding the molecular basis of behaviour in model organisms. However, most current descriptions of behaviour are based on manually identified events or a limited set of quantitative parameters. Here we report an extension of the concept of behavioural motifs to exhaustively catalogue C. elegans locomotion and derive a repertoire that is quantifiably complete. A repertoire learned for spontaneous behaviour in wild-type worms can be used to fit data from mutants or worms in different environmental conditions and provides a sensitive measure of phenotypic similarity. Repertoire comparison can also be used to assess inter-individual variation and the compositionality of behaviour, that is, the extent to which behavioural adaptation involves the creation of novel repertoire elements or the reuse of existing elements in novel sequences. Repertoire derivation is general, so that given a representation of posture, our approach will apply to other organisms.

  10. Using a robot to study the evolution of legged locomotion

    NASA Astrophysics Data System (ADS)

    McInroe, Benjamin; Astley, Henry; Goldman, Daniel I.

    2014-03-01

    Throughout history, many organisms have used flipper-like limbs for both aquatic and terrestrial locomotion. Modern examples include mudskippers and sea turtles; extinct examples include walkers such as the early tetrapodIchthyostega. In the transition from an aquatic to a terrestrial environment, early walkers had to adapt to the challenges of locomotion over flowable media like sand and mud. Previously, we discovered that a flipper with an elbow-like joint that could passively flex and extend toward and away from the body aided crawling on dry granular media [Mazouchova et. al. 2013], a result related to the jamming of material behind and beneath the flipper. To gain insight into how an additional degree of freedom of this joint affects flipper-based locomotors, we have built a robotic model with limb-joint morphology inspired by Ichthyostega. We add to our previous limb design a passive degree of freedom that allows for supination/pronation of the flipper about a variable insertion angle. Springs at the joints restore the flippers to equilibrium positions after interaction with the media. We study the crutching locomotion of the robot performing a symmetric gait, varying flipper-joint degrees of freedom and limb cycle frequency. This work was supported by NSF PoLS.

  11. A scattering approach for locomotion on heterogeneous granular media

    NASA Astrophysics Data System (ADS)

    Zhang, Tingnan; Qian, Feifei; Kamor, Adam; Cvitanovic, Predrag; Goldman, Daniel

    2014-03-01

    Locomotion on homogeneous particulate media has been recently studied using biological and robotic experiment and modeled using multi-particle discrete element simulation and empirical resistive force theory. Little is known about how locomotion is affected when environments are composed of particles with a large distribution of sizes. We study in experiment and a reduced order model, locomotion dynamics when particle sizes are widely separated. A hexapedal robot (~15 cm, ~100 g) interacts with a single boulder (whose size is comparable to the robot) during runs on a substrate of homogeneous, loosely packed poppy seeds. We vary the perpendicular distance between the center of the boulder and the trajectory of the robot's center of mass (CoM) before collision (the impact parameter), and measure the post-collision direction. For fixed impact parameter, the CoM deflection sensitively depends on the boulder contact point and leg phase. Counterintuitively, the interactions are largely attractive; the robot turns towards the scattering center. To understand the long-time dynamics, in a reduced-order model, we treat the scattering angle as a function of only the impact parameter with other effects modeled as noise; we thereby extend the study to an infinite field of boulders. This work is supported by DARPA.

  12. Brief anesthesia, but not voluntary locomotion, significantly alters cortical temperature

    PubMed Central

    Shirey, Michael J.; Kudlik, D'Anne E.; Huo, Bing-Xing; Greene, Stephanie E.; Drew, Patrick J.

    2015-01-01

    Changes in brain temperature can alter electrical properties of neurons and cause changes in behavior. However, it is not well understood how behaviors, like locomotion, or experimental manipulations, like anesthesia, alter brain temperature. We implanted thermocouples in sensorimotor cortex of mice to understand how cortical temperature was affected by locomotion, as well as by brief and prolonged anesthesia. Voluntary locomotion induced small (∼0.1°C) but reliable increases in cortical temperature that could be described using a linear convolution model. In contrast, brief (90-s) exposure to isoflurane anesthesia depressed cortical temperature by ∼2°C, which lasted for up to 30 min after the cessation of anesthesia. Cortical temperature decreases were not accompanied by a concomitant decrease in the γ-band local field potential power, multiunit firing rate, or locomotion behavior, which all returned to baseline within a few minutes after the cessation of anesthesia. In anesthetized animals where core body temperature was kept constant, cortical temperature was still >1°C lower than in the awake animal. Thermocouples implanted in the subcortex showed similar temperature changes under anesthesia, suggesting these responses occur throughout the brain. Two-photon microscopy of individual blood vessel dynamics following brief isoflurane exposure revealed a large increase in vessel diameter that ceased before the brain temperature significantly decreased, indicating cerebral heat loss was not due to increased cerebral blood vessel dilation. These data should be considered in experimental designs recording in anesthetized preparations, computational models relating temperature and neural activity, and awake-behaving methods that require brief anesthesia before experimental procedures. PMID:25972579

  13. The Kinematics of Treadmill Locomotion in Space

    NASA Technical Reports Server (NTRS)

    Thornton, W. E.; Cavanagh, P. R.; Buczek, F. L.; Burgess-Milliron, M. J.; Davis, B. L.

    1997-01-01

    Locomotion on a treadmill in 0 G will probably remain a centerpiece of NASA's exercise countermeasures programme. This form of physical activity has the potential to cause large bone and muscle forces as well as loading during a period of continuous treadmill exercise. A critical concern is the provision of a treadmill which can approximate 1 G performance in space. At this point, no adequate objective measurements of in-flight treadmill kinetics or of the human response to this activity have been made. Interpretation of the results obtained in the present study is limited by the following: (1) bungee tensions were not measured; (2) ground reaction forces were not measured in parallel with the kinematic measurements; and (3) the instrumentation used to film the astronauts could itself have been affected by microgravity. Despite these shortcomings, what is apparent is that exercise during NASA missions STS 7 and STS 8 resulted in leg motions that were similar to those found during 1 G locomotion on an inclined passive treadmill and on an active treadmill at an even steeper grade. In addition, it was apparent that the majority of the loads were transmitted through the forefoot, and one can surmise that this style of running would result in physiologically significant tensions in the calf musculature and resultant ankle compressive loading. Further speculation regarding limb loading is complicated by the fact that varying amounts of force are transmitted through (1) the treadmill handle and (2) bungee cords that act as a tether. New generations of treadmills are being manufactured that could provide I important information for planners of long-duration space missions. If these types of treadmill are flown on future missions, it will be possible to control bungee tensions more precisely, control for grade and speed, and, most importantly, provide data on the rates and magnitudes of limb loading. These data could then be incorporated into biomechanical models of the

  14. Biomechanics of locomotion in Asian elephants.

    PubMed

    Genin, J J; Willems, P A; Cavagna, G A; Lair, R; Heglund, N C

    2010-03-01

    Elephants are the biggest living terrestrial animal, weighing up to five tons and measuring up to three metres at the withers. These exceptional dimensions provide certain advantages (e.g. the mass-specific energetic cost of locomotion is decreased) but also disadvantages (e.g. forces are proportional to body volume while supportive tissue strength depends on their cross-sectional area, which makes elephants relatively more fragile than smaller animals). In order to understand better how body size affects gait mechanics the movement of the centre of mass (COM) of 34 Asian elephants (Elephas maximus) was studied over their entire speed range of 0.4-5.0 m s(-1) with force platforms. The mass-specific mechanical work required to maintain the movements of the COM per unit distance is approximately 0.2 J kg(-1) m(-1) (about 1/3 of the average of other animals ranging in size from a 35 g kangaroo rat to a 70 kg human). At low speeds this work is reduced by a pendulum-like exchange between the kinetic and potential energies of the COM, with a maximum energy exchange of approximately 60% at 1.4 m s(-1). At high speeds, elephants use a bouncing mechanism with little exchange between kinetic and potential energies of the COM, although without an aerial phase. Elephants increase speed while reducing the vertical oscillation of the COM from about 3 cm to 1 cm. PMID:20154184

  15. Motoneuronal and muscle synergies involved in cat hindlimb control during fictive and real locomotion: a comparison study.

    PubMed

    Markin, Sergey N; Lemay, Michel A; Prilutsky, Boris I; Rybak, Ilya A

    2012-04-01

    We compared the activity profiles and synergies of spinal motoneurons recorded during fictive locomotion evoked in immobilized decerebrate cat preparations by midbrain stimulation to the activity profiles and synergies of the corresponding hindlimb muscles obtained during forward level walking in cats. The fictive locomotion data were collected in the Spinal Cord Research Centre, University of Manitoba, and provided by Dr. David McCrea; the real locomotion data were obtained in the laboratories of M. A. Lemay and B. I. Prilutsky. Scatterplot representation and minimum spanning tree clustering algorithm were used to identify the possible motoneuronal and muscle synergies operating during both fictive and real locomotion. We found a close similarity between the activity profiles and synergies of motoneurons innervating one-joint muscles during fictive locomotion and the profiles and synergies of the corresponding muscles during real locomotion. However, the activity patterns of proximal nerves controlling two-joint muscles, such as posterior biceps and semitendinosus (PBSt) and rectus femoris (RF), were not uniform in fictive locomotion preparations and differed from the activity profiles of the corresponding two-joint muscles recorded during forward level walking. Moreover, the activity profiles of these nerves and the corresponding muscles were unique and could not be included in the synergies identified in fictive and real locomotion. We suggest that afferent feedback is involved in the regulation of locomotion via motoneuronal synergies controlled by the spinal central pattern generator (CPG) but may also directly affect the activity of motoneuronal pools serving two-joint muscles (e.g., PBSt and RF). These findings provide important insights into the organization of the spinal CPG in mammals, the motoneuronal and muscle synergies engaged during locomotion, and their afferent control. PMID:22190626

  16. Motoneuronal and muscle synergies involved in cat hindlimb control during fictive and real locomotion: a comparison study

    PubMed Central

    Markin, Sergey N.; Lemay, Michel A.; Prilutsky, Boris I.

    2012-01-01

    We compared the activity profiles and synergies of spinal motoneurons recorded during fictive locomotion evoked in immobilized decerebrate cat preparations by midbrain stimulation to the activity profiles and synergies of the corresponding hindlimb muscles obtained during forward level walking in cats. The fictive locomotion data were collected in the Spinal Cord Research Centre, University of Manitoba, and provided by Dr. David McCrea; the real locomotion data were obtained in the laboratories of M. A. Lemay and B. I. Prilutsky. Scatterplot representation and minimum spanning tree clustering algorithm were used to identify the possible motoneuronal and muscle synergies operating during both fictive and real locomotion. We found a close similarity between the activity profiles and synergies of motoneurons innervating one-joint muscles during fictive locomotion and the profiles and synergies of the corresponding muscles during real locomotion. However, the activity patterns of proximal nerves controlling two-joint muscles, such as posterior biceps and semitendinosus (PBSt) and rectus femoris (RF), were not uniform in fictive locomotion preparations and differed from the activity profiles of the corresponding two-joint muscles recorded during forward level walking. Moreover, the activity profiles of these nerves and the corresponding muscles were unique and could not be included in the synergies identified in fictive and real locomotion. We suggest that afferent feedback is involved in the regulation of locomotion via motoneuronal synergies controlled by the spinal central pattern generator (CPG) but may also directly affect the activity of motoneuronal pools serving two-joint muscles (e.g., PBSt and RF). These findings provide important insights into the organization of the spinal CPG in mammals, the motoneuronal and muscle synergies engaged during locomotion, and their afferent control. PMID:22190626

  17. Characteristics of undulatory locomotion in granular media

    NASA Astrophysics Data System (ADS)

    Peng, Zhiwei; Pak, On Shun; Elfring, Gwynn J.

    2016-03-01

    Undulatory locomotion is ubiquitous in nature and observed in different media, from the swimming of flagellated microorganisms in biological fluids, to the slithering of snakes on land, or the locomotion of sandfish lizards in sand. Despite the similarity in the undulating pattern, the swimming characteristics depend on the rheological properties of different media. Analysis of locomotion in granular materials is relatively less developed compared with fluids partially due to a lack of validated force models but recently a resistive force theory in granular media has been proposed and shown useful in studying the locomotion of a sand-swimming lizard. Here we employ the proposed model to investigate the swimming characteristics of a slender filament, of both finite and infinite length, undulating in a granular medium and compare the results with swimming in viscous fluids. In particular, we characterize the effects of drifting and pitching in terms of propulsion speed and efficiency for a finite sinusoidal swimmer. We also find that, similar to Lighthill's results using resistive force theory in viscous fluids, the sawtooth swimmer is the optimal waveform for propulsion speed at a given power consumption in granular media. The results complement our understanding of undulatory locomotion and provide insights into the effective design of locomotive systems in granular media.

  18. Characterization of undulatory locomotion in granular media

    NASA Astrophysics Data System (ADS)

    Peng, Zhiwei; Pak, On Shun; Elfring, Gwynn

    2015-11-01

    Undulatory locomotion is ubiquitous in nature, from the swimming of flagellated microorganisms in biological fluids, to the slithering of snakes on land, or the locomotion of sandfish lizards in sand. Analysis of locomotion in granular materials is relatively less developed compared with fluids partially due to a lack of validated force models but a recently proposed resistive force theory (RFT) in granular media has been shown useful in studying the locomotion of a sand-swimming lizard. Here we employ this model to investigate the swimming characteristics of an undulating slender filament of both finite and infinite length. For infinite swimmers, similar to results in viscous fluids, the sawtooth waveform is found to be optimal for propulsion speed at a given power consumption. We also compare the swimming characteristics of sinusoidal and sawtooth swimmers with swimming in viscous fluids. More complex swimming dynamics emerge when the assumption of an infinite swimmer is removed. In particular, we characterize the effects of drifting and pitching in terms of propulsion speed and efficiency for a finite sinusoidal swimmer. The results complement our understanding of undulatory locomotion and provide insights into the effective design of locomotive systems in granular media.

  19. Push-Pull Locomotion for Vehicle Extrication

    NASA Technical Reports Server (NTRS)

    Creager, Colin M.; Johnson, Kyle A.; Plant, Mark; Moreland, Scott J.; Skonieczny, Krzysztof

    2014-01-01

    For applications in which unmanned vehicles must traverse unfamiliar terrain, there often exists the risk of vehicle entrapment. Typically, this risk can be reduced by using feedback from on-board sensors that assess the terrain. This work addressed the situations where a vehicle has already become immobilized or the desired route cannot be traversed using conventional rolling. Specifically, the focus was on using push-pull locomotion in high sinkage granular material. Push-pull locomotion is an alternative mode of travel that generates thrust through articulated motion, using vehicle components as anchors to push or pull against. It has been revealed through previous research that push-pull locomotion has the capacity for generating higher net traction forces than rolling, and a unique optical flow technique indicated that this is the result of a more efficient soil shearing method. It has now been found that pushpull locomotion results in less sinkage, lower travel reduction, and better power efficiency in high sinkage material as compared to rolling. Even when starting from an "entrapped" condition, push-pull locomotion was able to extricate the test vehicle. It is the authors' recommendation that push-pull locomotion be considered as a reliable back-up mode of travel for applications where terrain entrapment is a possibility.

  20. Patterned control of human locomotion.

    PubMed

    Lacquaniti, Francesco; Ivanenko, Yuri P; Zago, Myrka

    2012-05-15

    There is much experimental evidence for the existence of biomechanical constraints which simplify the problem of control of multi-segment movements. In addition, it has been hypothesized that movements are controlled using a small set of basic temporal components or activation patterns, shared by several different muscles and reflecting global kinematic and kinetic goals. Here we review recent studies on human locomotion showing that muscle activity is accounted for by a combination of few basic patterns, each one timed at a different phase of the gait cycle. Similar patterns are involved in walking and running at different speeds, walking forwards or backwards, and walking under different loading conditions. The corresponding weights of distribution to different muscles may change as a function of the condition, allowing highly flexible control. Biomechanical correlates of each activation pattern have been described, leading to the hypothesis that the co-ordination of limb and body segments arises from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle activations need only intervene during limited time epochs to force intrinsic oscillations of the system when energy is lost. PMID:22411012

  1. Bipedal locomotion in granular media

    NASA Astrophysics Data System (ADS)

    Kingsbury, Mark; Zhang, Tingnan; Goldman, Daniel

    Bipedal walking, locomotion characterized by alternating swing and double support phase, is well studied on ground where feet do not penetrate the substrate. On granular media like sand however, intrusion and extrusion phases also occur. In these phases, relative motion of the two feet requires that one or both feet slip through the material, degrading performance. To study walking in these phases, we designed and studied a planarized bipedal robot (1.6 kg, 42 cm) that walked in a fluidized bed of poppy seeds. We also simulated the robot in a multibody software environment (Chrono) using granular resistive force theory (RFT) to calculate foot forces. In experiment and simulation, the robot experienced slip during the intrusion phase, with the experiment presenting additional slip due to motor control error during the double support phase. This exaggerated slip gave insight (through analysis of ground reaction forces in simulation) into how slip occurs when relative motion exists between the two feet in the granular media, where the foot with higher relative drag forces (from its instantaneous orientation, rotation, relative direction of motion, and depth) remains stationary. With this relationship, we generated walking gaits for the robot to walk with minimal slip.

  2. Gravitational Effects upon Locomotion Posture

    NASA Technical Reports Server (NTRS)

    DeWitt, John K.; Bentley, Jason R.; Edwards, W. Brent; Perusek, Gail P.; Samorezov, Sergey

    2008-01-01

    Researchers use actual microgravity (AM) during parabolic flight and simulated microgravity (SM) obtained with horizontal suspension analogs to better understand the effect of gravity upon gait. In both environments, the gravitational force is replaced by an external load (EL) that returns the subject to the treadmill. However, when compared to normal gravity (N), researchers consistently find reduced ground reaction forces (GRF) and subtle kinematic differences (Schaffner et al., 2005). On the International Space Station, the EL is applied by elastic bungees attached to a waist and shoulder harness. While bungees can provide EL approaching body weight (BW), their force-length characteristics coupled with vertical oscillations of the body during gait result in a variable load. However, during locomotion in N, the EL is consistently equal to 100% body weight. Comparisons between AM and N have shown that during running, GRF are decreased in AM (Schaffner et al, 2005). Kinematic evaluations in the past have focussed on joint range of motion rather than joint posture at specific instances of the gait cycle. The reduced GRF in microgravity may be a result of differing hip, knee, and ankle positions during contact. The purpose of this investigation was to compare joint angles of the lower extremities during walking and running in AM, SM, and N. We hypothesized that in AM and SM, joints would be more flexed at heel strike (HS), mid-stance (MS) and toe-off (TO) than in N.

  3. A case of ovarian torsion in a patient carrier of a FSH receptor gene mutation previously affected by spontaneous ovarian hyperstimulation syndrome.

    PubMed

    Di Carlo, C; Savoia, F; Fabozzi, A; Gargano, V; Nappi, C

    2015-02-01

    We here report a case of ovarian torsion in a patient with an history of two previous episodes of spontaneous ovarian hyperstimulation syndrome during her two pregnancies. A mutation of follicle-stimulating hormone receptor (FSHr) gene was identified in this patient and in other members of the family. Two years after her successful second pregnancy, the patient showed signs of severe thyroiditis during administration of oral contraceptive, with suppressed TSH and increased thyreoglobulin, in the absence of any abnormalities of the auto-antibodies. In few days, she developed severe pelvic pain and ultrasonographic evidence of increased ovarian volume. She underwent laparoscopy with unilateral adnexectomy for ovarian ischemic necrosis due to adnexal torsion. Our experience suggests that patients' carrier of a mutation of FSHr gene are at risk of ovarian pathologies also when non-pregnant and in the presence of low TSH levels. Further investigations are needed for an appropriate knowledge of typical and atypical manifestations of spontaneous ovarian hyperstimulation syndrome. PMID:25495063

  4. A study of snake-like locomotion through the analysis of a flexible robot model

    PubMed Central

    Cicconofri, Giancarlo; DeSimone, Antonio

    2015-01-01

    We examine the problem of snake-like locomotion by studying a system consisting of a planar inextensible elastic rod with adjustable spontaneous curvature, which provides an internal actuation mechanism that mimics muscular action in a snake. Using a Cosserat model, we derive the equations of motion in two special cases: one in which the rod can only move along a prescribed curve, and one in which the rod is constrained to slide longitudinally without slipping laterally, but the path is not fixed a priori (free-path case). The second setting is inspired by undulatory locomotion of snakes on flat surfaces. The presence of constraints leads in both cases to non-standard boundary conditions that allow us to close and solve the equations of motion. The kinematics and dynamics of the system can be recovered from a one-dimensional equation, without any restrictive assumption on the followed trajectory or the actuation. We derive explicit formulae highlighting the role of spontaneous curvature in providing the driving force (and the steering, in the free-path case) needed for locomotion. We also provide analytical solutions for a special class of serpentine motions, which enable us to discuss the connection between observed trajectories, internal actuation and forces exchanged with the environment. PMID:26807040

  5. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were established to protect the public health or welfare from the dangers of air pollution.” (2) A statement that... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES...

  6. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were established to protect the public health or welfare from the dangers of air pollution.” (2) A statement that... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES...

  7. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were established to protect the public health or welfare from the dangers of air pollution.” (2) A statement that... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES...

  8. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate with a yield strength of 25,000 pounds-per-square-inch—material of a higher yield strength may be used to decrease the required thickness of the material provided at least an equivalent level of strength...

  9. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate with a yield strength of 25,000 pounds-per-square-inch—material of a higher yield strength may be used to decrease the required thickness of the material provided at least an equivalent level of strength...

  10. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate with a yield strength of 25,000 pounds-per-square-inch—material of a higher yield strength may be used to decrease the required thickness of the material provided at least an equivalent level of strength...

  11. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Forward end structure of locomotives, including cab cars and MU locomotives. 238.209 Section 238.209 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PASSENGER EQUIPMENT SAFETY STANDARDS Specific Requirements...

  12. Relationship between osteology and aquatic locomotion in birds: determining modes of locomotion in extinct Ornithurae.

    PubMed

    Hinić-Frlog, S; Motani, R

    2010-02-01

    The evolutionary history of aquatic invasion in birds would be incomplete without incorporation of extinct species. We show that aquatic affinities in fossil birds can be inferred by multivariate analysis of skeletal features and locomotion of 245 species of extant birds. Regularized discriminant analyses revealed that measurements of appendicular skeletons successfully separated diving birds from surface swimmers and flyers, while also discriminating among different underwater modes of swimming. The high accuracy of this method allows detection of skeletal characteristics that are indicative of aquatic locomotion and inference of such locomotion in bird species with insufficient behavioural information. Statistical predictions based on the analyses confirm qualitative assessments for both foot-propelled (Hesperornithiformes) and wing-propelled (Copepteryx) underwater locomotion in fossil birds. This is the first quantitative inference of underwater modes of swimming in fossil birds, enabling future studies of locomotion in extinct birds and evolutionary transitions among locomotor modes in avian lineage. PMID:20021550

  13. Locomotion and self-administration induced by cocaine in 129/OlaHsd mice lacking galanin

    PubMed Central

    Brabant, Christian; Kuschpel, Anna S; Picciotto, Marina R

    2010-01-01

    Previous studies have demonstrated that the galanin system modulates responses to drugs of abuse such as morphine. The current study examined whether genetic deletion of galanin could affect the locomotor and reinforcing effects of cocaine in mice. We examined spontaneous motor activity and cocaine-induced hyperactivity in wild-type (GAL-WT) and knockout mice lacking galanin (GAL-KO) maintained on the 129/OlaHsd background. Our results indicate that cocaine enhanced locomotion (defined as moving more than 5 cm) dose-dependently in GAL-WT and GAL-KO mice. However, general activity (total beam breaks) was increased by cocaine only in GAL-WT mice. An additional experiment indicated that galnon, a non-selective galanin receptor agonist, did not affect cocaine-induced hyperactivity. In a second set of experiments, mice of both genotypes were trained to self-administer cocaine under a fixed ratio schedule and tested with various doses of cocaine under different schedules of reinforcement. This set of experiments showed that cocaine self-administration did not differ markedly between genotypes. However, while GAL-WT mice acquired cocaine self-administration, a median split analysis showed that mice could be divided into large and small drug takers, whereas all GAL-KO mice were small drug takers. Our results indicate that wild-type and galanin knockout mice on a congenic 129/OlaHsd background are responsive to the locomotor effects of cocaine and can acquire i.v. cocaine self-administration. However, the phenotype observed in GAL-KO mice does not support a major role for galanin in cocaine-induced hyperlocomotion and self-administration. PMID:21038934

  14. Evolution of neural controllers for salamanderlike locomotion

    NASA Astrophysics Data System (ADS)

    Ijspeert, Auke J.

    1999-08-01

    This paper presents an experiment in which evolutionary algorithms are used for the development of neural controllers for salamander locomotion. The aim of the experiment is to investigate which kind of neural circuitry can produce the typical swimming and trotting gaits of the salamander, and to develop a synthetic approach to neurobiology by using genetic algorithms as design tool. A 2D bio-mechanical simulation of the salamander's body is developed whose muscle contraction is determined by the locomotion controller simulated as continuous-time neural networks. While the connectivity of the neural circuitry underlying locomotion in the salamander has not been decoded for the moment, the general organization of the designed neural circuits corresponds to that hypothesized by neurobiologist for the real animal. In particular, the locomotion controllers are based on a body central pattern generator (CPG) corresponding to a lamprey-like swimming controller as developed by Ekeberg, and are extended with a limb CPG for controlling the salamander's body. A genetic algorithm is used to instantiate synaptic weights of the connections within the limb CPG and from the limb CPG to the body CPG given a high level description of the desired gaits. A set of biologically plausible controllers are thus developed which can produce a neural activity and locomotion gaits very similar to those observed in the real salamander. By simply varying the external excitation applied to the network, the speed, direction and type of gait can be varied.

  15. [Possible changes in energy-minimizer mechanisms of locomotion due to chronic low back pain - a literature review].

    PubMed

    de Carvalho, Alberito Rodrigo; Andrade, Alexandro; Peyré-Tartaruga, Leonardo Alexandre

    2015-01-01

    One goal of the locomotion is to move the body in the space at the most economical way possible. However, little is known about the mechanical and energetic aspects of locomotion that are affected by low back pain. And in case of occurring some damage, little is known about how the mechanical and energetic characteristics of the locomotion are manifested in functional activities, especially with respect to the energy-minimizer mechanisms during locomotion. This study aimed: a) to describe the main energy-minimizer mechanisms of locomotion; b) to check if there are signs of damage on the mechanical and energetic characteristics of the locomotion due to chronic low back pain (CLBP) which may endanger the energy-minimizer mechanisms. This study is characterized as a narrative literature review. The main theory that explains the minimization of energy expenditure during the locomotion is the inverted pendulum mechanism, by which the energy-minimizer mechanism converts kinetic energy into potential energy of the center of mass and vice-versa during the step. This mechanism is strongly influenced by spatio-temporal gait (locomotion) parameters such as step length and preferred walking speed, which, in turn, may be severely altered in patients with chronic low back pain. However, much remains to be understood about the effects of chronic low back pain on the individual's ability to practice an economic locomotion, because functional impairment may compromise the mechanical and energetic characteristics of this type of gait, making it more costly. Thus, there are indications that such changes may compromise the functional energy-minimizer mechanisms. PMID:25440708

  16. Measurement techniques in animal locomotion analysis.

    PubMed

    Schamhardt, H C; van den Bogert, A J; Hartman, W

    1993-01-01

    Animal performance can be determined by subjective observations or objective measurements. Numerical data are only then superior to results of subjective observations when they are the result of measurements carried out to test a well-defined hypothesis or to give the answer to a clear, precisely formulated question. In the analysis of kinematics a careful evaluation of the set-up of the measurement equipment and the resulting accuracy in the data is required. Measurements in three dimensions (3D) are theoretically better than those in 2D. Practically, however, collection, analysis, interpretation and presentation of 3D data are so much more complicated that frequently 2D analysis appears to be more useful. The minimal size of markers necessary to obtain a certain accuracy in kinematic data is usually too big for practical use. Smaller markers impair accuracy. Reduction of measurement noise is obligatory when time derivatives are to be calculated. Skin movement artefacts cannot be removed by data smoothing. Forces occurring between the digits and the ground can be determined using a force plate or an instrumented shoe. A force plate is accurate, but repeated trials are necessary. Using a force shoe each ground contact results in useful data. However, the shoe itself may affect locomotion. Surface strains on long bones can be recorded relatively easily. Determination of loading forces from surface strains is complicated but can be carried out using multiple strain gauges and a post-mortem calibration test. Strain in tendons is difficult to measure due to problems in defining a'zero' or reference length.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8470454

  17. Stabilization of cat paw trajectory during locomotion.

    PubMed

    Klishko, Alexander N; Farrell, Bradley J; Beloozerova, Irina N; Latash, Mark L; Prilutsky, Boris I

    2014-09-15

    We investigated which of cat limb kinematic variables during swing of regular walking and accurate stepping along a horizontal ladder are stabilized by coordinated changes of limb segment angles. Three hypotheses were tested: 1) animals stabilize the entire swing trajectory of specific kinematic variables (performance variables); and 2) the level of trajectory stabilization is similar between regular and ladder walking and 3) is higher for forelimbs compared with hindlimbs. We used the framework of the uncontrolled manifold (UCM) hypothesis to quantify the structure of variance of limb kinematics in the limb segment orientation space across steps. Two components of variance were quantified for each potential performance variable, one of which affected it ("bad variance," variance orthogonal to the UCM, VORT) while the other one did not ("good variance," variance within the UCM, VUCM). The analysis of five candidate performance variables revealed that cats during both locomotor behaviors stabilize 1) paw vertical position during the entire swing (VUCM > VORT, except in mid-hindpaw swing of ladder walking) and 2) horizontal paw position in initial and terminal swing (except for the entire forepaw swing of regular walking). We also found that the limb length was typically stabilized in midswing, whereas limb orientation was not (VUCM ≤ VORT) for both limbs and behaviors during entire swing. We conclude that stabilization of paw position in early and terminal swing enables accurate and stable locomotion, while stabilization of vertical paw position in midswing helps paw clearance. This study is the first to demonstrate the applicability of the UCM-based analysis to nonhuman movement. PMID:24899676

  18. Stabilization of cat paw trajectory during locomotion

    PubMed Central

    Klishko, Alexander N.; Farrell, Bradley J.; Beloozerova, Irina N.; Latash, Mark L.

    2014-01-01

    We investigated which of cat limb kinematic variables during swing of regular walking and accurate stepping along a horizontal ladder are stabilized by coordinated changes of limb segment angles. Three hypotheses were tested: 1) animals stabilize the entire swing trajectory of specific kinematic variables (performance variables); and 2) the level of trajectory stabilization is similar between regular and ladder walking and 3) is higher for forelimbs compared with hindlimbs. We used the framework of the uncontrolled manifold (UCM) hypothesis to quantify the structure of variance of limb kinematics in the limb segment orientation space across steps. Two components of variance were quantified for each potential performance variable, one of which affected it (“bad variance,” variance orthogonal to the UCM, VORT) while the other one did not (“good variance,” variance within the UCM, VUCM). The analysis of five candidate performance variables revealed that cats during both locomotor behaviors stabilize 1) paw vertical position during the entire swing (VUCM > VORT, except in mid-hindpaw swing of ladder walking) and 2) horizontal paw position in initial and terminal swing (except for the entire forepaw swing of regular walking). We also found that the limb length was typically stabilized in midswing, whereas limb orientation was not (VUCM ≤ VORT) for both limbs and behaviors during entire swing. We conclude that stabilization of paw position in early and terminal swing enables accurate and stable locomotion, while stabilization of vertical paw position in midswing helps paw clearance. This study is the first to demonstrate the applicability of the UCM-based analysis to nonhuman movement. PMID:24899676

  19. Locomotion gaits of a rotating cylinder pair

    NASA Astrophysics Data System (ADS)

    van Rees, Wim M.; Novati, Guido; Koumoutsakos, Petros; Mahadevan, L.

    2015-11-01

    Using 2D numerical simulations of the Navier-Stokes equations, we demonstrate that a simple pair of rotating cylinders can display a range of locomotion patterns of biological and engineering interest. Steadily counter-rotating the cylinders causes the pair to move akin to a vortex dipole for low rotation rates, but as the rotational velocity is increased the direction of motion reverses. Unsteady rotations lead to different locomotion gaits that resemble jellyfish (for in-phase rotations) and undulating swimmers (for out-of-phase rotations). The small number of parameters for this simple system allows us to systematically map the phase space of these gaits, and allows us to understand the underlying physical mechanisms using a minimal model with implications for biological locomotion and engineered analogs.

  20. Passive appendages aid locomotion through symmetry breaking

    NASA Astrophysics Data System (ADS)

    Bagheri, Shervin; Lacis, Ugis; Mazzino, Andrea; Kellay, Hamid; Brosse, Nicolas; Lundell, Fredrik; Ingremeau, Francois

    2014-11-01

    Plants and animals use plumes, barbs, tails, feathers, hairs, fins, and other types of appendages to aid locomotion. Despite their enormous variation, passive appendages may contribute to locomotion by exploiting the same physical mechanism. We present a new mechanism that applies to body appendages surrounded by a separated flow, which often develops behind moving bodies larger than a few millimeters. We use theory, experiments, and numerical simulations to show that bodies with protrusions turn and drift by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in flowing fluid is unstable and how it stabilizes either to the left or right of the incoming fluid flow direction. The discovery suggests a new mechanism of locomotion that may be relevant for certain organisms; for example, how plumed seeds may drift without wind and how motile animals may passively reorient themselves.

  1. Operating a locomotive on liquid methane fuel

    SciTech Connect

    Stolz, J.L. )

    1992-04-01

    This paper reports that several years ago, Burlington Northern Railroad looked into the feasibility of operating a diesel railroad locomotive to also run on compressed natural gas in a dual-fuel mode. Recognizing the large volume of on-board storage required and other limitations of CNG in the application, a program was begun to fuel a locomotive with liquefied natural gas. Because natural gas composition can vary with source and processing, it was considered desirable to use essentially pure liquid methane as the engine fuel. Initial testing results show the locomotive system achieved full diesel-rated power when operating on liquid methane and with equivalent fuel efficiency. Extended testing, including an American Association of Railroad 500-hour durability test, was undertaken to obtain information on engine life, wear rate and lubrication oil life.

  2. Corticotropin-releasing factor enhances locomotion and medullary neuronal firing in an amphibian.

    PubMed

    Lowry, C A; Rose, J D; Moore, F L

    1996-03-01

    Corticotropin-releasing factor (CRF) administration has been shown to act centrally to enhance locomotion in rats and amphibians. In the present study we used an amphibian, the roughskin newt (Taricha granulosa), to characterize changes in medullary neuronal activity associated with CRF-induced walking and swimming in animals chronically implanted with fine-wire microelectrodes. Neuronal activity was recorded from the raphe and adjacent reticular region of the rostral medulla. Under baseline conditions most of the recorded neurons showed low to moderate amounts of neuronal activity during periods of immobility and pronounced increases in firing that were time-locked with episodes of walking. These neurons sometimes showed further increases in discharge during swimming. Injections of CRF but not saline into the lateral ventricle produced a rapidly appearing increase in walking and pronounced changes (mostly increases) in firing rates of the medullary neurons. CRF produced diverse changes in patterns of firing in different neurons, but for these neurons as a group, the effects of CRF showed a close temporal association with the onset and expression of the peptide's effect on locomotion. In neurons that were active exclusively during movement prior to CRF treatment, the post-CRF increase in firing was evident during episodes of walking; in other neurons that also were spontaneously active during immobility prior to CRF infusion, post-CRF activity changes were evident during immobility as well as during episodes of locomotion. Thus, a principal effect of CRF was to potentiate the level of neuronal firing in a population of medullary neurons with locomotor-related properties. Due to the route of administration CRF may have acted on multiple central nervous system sites to enhance locomotion, but the results are consistent with neurophysiological effects involving medullary locomotion-regulating neurons. PMID:8724179

  3. The kinematics of locomotion in caecilians: effects of substrate and body shape.

    PubMed

    Herrel, Anthony; Measey, G John

    2010-06-01

    Caecilians are limbless amphibians that have radiated extensively in the tropics, and have evolved distinct cranial and postcranial specializations associated with a burrowing lifestyle. Some species are recognized as being surface active, whereas others are dedicated burrowers. Previous authors have demonstrated that some caecilians use a hydrostatic mechanism to generate burrowing forces which is dependent on the existence of skin-vertebral independence. It has been hypothesized that skin-vertebral independence may be lost in extremely elongated species, thus affecting their ability to burrow. Here, we use X-ray video to study the kinematics of locomotion in five species of caecilian differing in their degree of body elongation. Animals were filmed moving in or across different substrates imposing different functional demands on the locomotor system. Our data demonstrate that all species have the ability to perform internal concertina locomotion, but indicate differences between species in the kinematics of locomotion with more elongate species showing a smaller degree of skin-vertebral independence. In all species, locomotion was dependent on the substrate and species switched from using lateral undulation on the surface substrates to the use of whole body or internal concertina in wide and narrow tunnels, respectively. When burrowing in soil, all species used a combination of whole-body and internal concertina locomotion. Additional studies on the ability of different species to generate forces are needed to test whether the reduced skin-vertebral independence in elongate forms has resulted in a decreased ability to generate burrows. PMID:20301183

  4. 8. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL LOCOMOTIVE NO. 6734 ON TURNTABLE, adjacent to Erecting Shop and Machine Shop - Juniata Shops, Turntable, South of Sixth Street at Third Avemue, Altoona, Blair County, PA

  5. 5. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL LOCOMOTIVE NO. 6734 ON TURNTABLE, adjacent to Erecting Shop and Machine Shop - Juniata Shops, Turntable, South of Sixth Street at Third Avemue, Altoona, Blair County, PA

  6. 6. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL LOCOMOTIVE NO. 6734 ON TURNTABLE, adjacent to Erecting Shop and Machine Shop - Juniata Shops, Turntable, South of Sixth Street at Third Avemue, Altoona, Blair County, PA

  7. 4. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL LOCOMOTIVE NO. 6734 ON TURNTABLE, adjacent to Erecting Shop and Machine Shop - Juniata Shops, Turntable, South of Sixth Street at Third Avemue, Altoona, Blair County, PA

  8. 7. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL LOCOMOTIVE NO. 6734 ON TURNTABLE, adjacent to Erecting Shop and Machine Shop - Juniata Shops, Turntable, South of Sixth Street at Third Avemue, Altoona, Blair County, PA

  9. 9. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. VIEW OF SHUNT LOCOMOTIVE NO. 9072 POSITIONING ELECTRIC DIESEL LOCOMOTIVE NO. 6734 ON TURNTABLE, adjacent to Erecting Shop and Machine Shop - Juniata Shops, Turntable, South of Sixth Street at Third Avemue, Altoona, Blair County, PA

  10. 7. Detail of the Grant Locomotive Works Erecting Shop looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Detail of the Grant Locomotive Works Erecting Shop looking southwest showing ruined wall and entrance of a single story addition. - Grant Locomotive Works, Market & Spruce Streets, Paterson, Passaic County, NJ

  11. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... under this part shall supply to the Administrator, upon his/her request, a reasonable number of... locomotives or locomotive engines that may be supplied to the Administrator is five per model year....

  12. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... under this part shall supply to the Administrator, upon his/her request, a reasonable number of... locomotives or locomotive engines that may be supplied to the Administrator is five per model year....

  13. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... under this part shall supply to the Administrator, upon his/her request, a reasonable number of... locomotives or locomotive engines that may be supplied to the Administrator is five per model year....

  14. 1. AERIAL VIEW SHOWING ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE PITS IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. AERIAL VIEW SHOWING ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE PITS IN FORMER ERECTING SHOP. MACHINE SHOP IS BUILDING AT RIGHT. - Grant Locomotive Works, Market & Spruce Streets, Paterson, Passaic County, NJ

  15. 2. CLOSE IN AERIAL VIEW OF ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. CLOSE IN AERIAL VIEW OF ARCHEOLOGICAL EXCAVATIONS OF LOCOMOTIVE PITS IN FORMER ERECTING SHOP. MACHINE SHOP IS BUILDING AT RIGHT. - Grant Locomotive Works, Market & Spruce Streets, Paterson, Passaic County, NJ

  16. Return of spontaneous Circulation Is Not Affected by Different Chest Compression Rates Superimposed with Sustained Inflations during Cardiopulmonary Resuscitation in Newborn Piglets

    PubMed Central

    Li, Elliott S.; Cheung, Po-Yin; Lee, Tze-Fun; Lu, Min; O'Reilly, Megan

    2016-01-01

    Objective Recently, sustained inflations (SI) during chest compression (CC) have been suggested as an alternative to the current approach during neonatal resuscitation. However, the optimal rate of CC during SI has not yet been established. Our aim was to determine whether different CC rates during SI reduce time to return of spontaneous circulation (ROSC) and improve hemodynamic recovery in newborn piglets with asphyxia-induced bradycardia. Intervention and measurements Term newborn piglets were anesthetized, intubated, instrumented and exposed to 45-min normocapnic hypoxia followed by asphyxia. Resuscitation was initiated when heart rate decreased to 25% of baseline. Piglets were randomized into three groups: CC superimposed by SI at a rate of 90 CC per minute (SI+CC 90, n = 8), CC superimposed by SI at a rate of 120 CC per minute (SI+CC 120, n = 8), or a sham group (n = 6). Cardiac function, carotid blood flow, cerebral oxygenation and respiratory parameters were continuously recorded throughout the experiment. Main results Both treatment groups had similar time of ROSC, survival rates, hemodynamic and respiratory parameters during cardiopulmonary resuscitation. The hemodynamic recovery in the subsequent 4h was similar in both groups and was only slightly lower than sham-operated piglets at the end of experiment. Conclusion Newborn piglets resuscitated by SI+CC 120 did not show a significant advantage in ROSC, survival, and hemodynamic recovery as compared to those piglets resuscitated by SI+CC 90. PMID:27304210

  17. Locomotion of Paramecium in patterned environments

    NASA Astrophysics Data System (ADS)

    Park, Eun-Jik; Eddins, Aja; Kim, Junil; Yang, Sung; Jana, Saikat; Jung, Sunghwan

    2011-10-01

    Ciliary organisms like Paramecium Multimicronucleatum locomote by synchronized beating of cilia that produce metachronal waves over their body. In their natural environments they navigate through a variety of environments especially surfaces with different topology. We study the effects of wavy surfaces patterned on the PDMS channels on the locomotive abilities of Paramecium by characterizing different quantities like velocity amplitude and wavelength of the trajectories traced. We compare this result with the swimming characteristics in straight channels and draw conclusions about the effects of various patterned surfaces.

  18. Large and limbless: the locomotion of snakes

    NASA Astrophysics Data System (ADS)

    Hu, David

    2008-03-01

    In efforts to understand snake locomotion, we consider one of their various gaits. By contracting and extending their bodies unidirectionally like a slinky, large snakes propel themselves in a straight line. In a combined experimental and theoretical investigation, we here report on the dynamics of a boa constrictor alongside the analysis of an n-linked extensible crawler model. Constraints on their locomotion are quantified and discussed, such as the elasticity, frictional anisotropy and abrasive wear of their skin. Also presented are certain snake behaviors that culminate in their tying themselves into knots.

  19. Propulsion by sinusoidal locomotion: A motion inspired by Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Ulrich, Xialing

    Sinusoidal locomotion is commonly seen in snakes, fish, nematodes, or even the wings of some birds and insects. This doctoral thesis presents the study of sinusoidal locomotion of the nematode C. elegans in experiments and the application of the state-space airloads theory to the theoretical forces of sinusoidal motion. An original MATLAB program has been developed to analyze the video records of C. elegans' movement in different fluids, including Newtonian and non-Newtonian fluids. The experimental and numerical studies of swimming C. elegans has revealed three conclusions. First, though the amplitude and wavelength are varying with time, the motion of swimming C. elegans can still be viewed as sinusoidal locomotion with slips. The average normalized wavelength is a conserved character of the locomotion for both Newtonian and non-Newtonian fluids. Second, fluid viscosity affects the frequency but not the moving speed of C. elegans, while fluid elasticity affects the moving speed but not the frequency. Third, by the resistive force theory, for more elastic fluids the ratio of resistive coefficients becomes smaller. Inspired by the motion of C. elegans and other animals performing sinusoidal motion, we investigated the sinusoidal motion of a thin flexible wing in theory. Given the equation of the motion, we have derived the closed forms of propulsive force, lift and other generalized forces applying on the wing. We also calculated the power required to perform the motion, the power lost due to the shed vortices and the propulsive efficiency. These forces and powers are given as functions of reduced frequency k, dimensionless wavelength z, dimensionless amplitude A/b, and time. Our results show that a positive, time-averaged propulsive force is produced for all k>k0=pi/ z. At k=k0, which implies the moment when the moving speed of the wing is the same as the wave speed of its undulation, the motion reaches a steady state with all forces being zero. If there were no

  20. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Body structure, MU locomotives. 229.141 Section... Cab Equipment § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... body structure designed to meet or exceed the following minimum specifications: (1) The body...

  1. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Body structure, MU locomotives. 229.141 Section 229.141 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Crashworthiness Design Requirements § 229.141 Body...

  2. 49 CFR 229.15 - Remote control locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Remote control locomotives. 229.15 Section 229.15 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS General § 229.15 Remote control locomotives. (a) Design and operation. (1)...

  3. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  4. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  5. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  6. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  7. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  8. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Body structure, MU locomotives. 229.141 Section... Design Requirements § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... body structure designed to meet or exceed the following minimum specifications: (1) The body...

  9. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  10. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  11. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  12. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  13. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  14. A Spontaneous Missense Mutation in Branched Chain Keto Acid Dehydrogenase Kinase in the Rat Affects Both the Central and Peripheral Nervous Systems

    PubMed Central

    Zigler, J. Samuel; Hodgkinson, Colin A.; Wright, Megan; Klise, Andrew; Broman, Karl W.; Huang, Hao; Patek, Bonnie; Sergeev, Yuri; Hose, Stacey; Xaiodong, Jiao; Vasquez, David; Maragakis, Nicholas; Mori, Susumu; Goldman, David; Sinha, Debasish

    2016-01-01

    A novel mutation, causing a phenotype we named frogleg because its most obvious characteristic is a severe splaying of the hind limbs, arose spontaneously in a colony of Sprague-Dawley rats. Frogleg is a complex phenotype that includes abnormalities in hind limb function, reduced brain weight with dilated ventricles and infertility. Using micro-satellite markers spanning the entire rat genome, the mutation was mapped to a region of rat chromosome 1 between D1Rat131 and D1Rat287. Analysis of whole genome sequencing data within the linkage interval, identified a missense mutation in the branched-chain alpha-keto dehydrogenase kinase (Bckdk) gene. The protein encoded by Bckdk is an integral part of an enzyme complex located in the mitochondrial matrix of many tissues which regulates the levels of the branched-chain amino acids (BCAAs), leucine, isoleucine and valine. BCAAs are essential amino acids (not synthesized by the body), and circulating levels must be tightly regulated; levels that are too high or too low are both deleterious. BCKDK phosphorylates Ser293 of the E1α subunit of the BCKDH protein, which catalyzes the rate-limiting step in the catabolism of the BCAAs, inhibiting BCKDH and thereby, limiting breakdown of the BCAAs. In contrast, when Ser293 is not phosphorylated, BCKDH activity is unchecked and the levels of the BCAAs will decrease dramatically. The mutation is located within the kinase domain of Bckdk and is predicted to be damaging. Consistent with this, we show that in rats homozygous for the mutation, phosphorylation of BCKDH in the brain is markedly decreased relative to wild type or heterozygous littermates. Further, circulating levels of the BCAAs are reduced by 70–80% in animals homozygous for the mutation. The frogleg phenotype shares important characteristics with a previously described Bckdk knockout mouse and with human subjects with Bckdk mutations. In addition, we report novel data regarding peripheral neuropathy of the hind limbs

  15. Factors affecting accumulation of thallium and other trace elements in two wild Brassicaceae spontaneously growing on soils contaminated by tailings dam waste.

    PubMed

    Madejón, P; Murillo, J M; Marañón, T; Lepp, N W

    2007-02-01

    Thallium is a scarce, highly toxic element. There are several investigations that report Tl accumulation in plants of the family Brassicaceae. These plants could pose a risk in areas where Tl is present at higher concentrations than normal soils. The present study reports analyses of two wild Brassicaceae, Hirschfeldia incana and Diplotaxis catholica, growing spontaneously at five sampling sites moderately polluted with Tl and other trace elements in the Green Corridor of the Guadiamar river, Seville, S. Spain. In general, trace element content was unremarkable in all part plants, despite the concentrations present in soil. Thallium was the only element whose concentration in both plant species was above normal for plants (maximum values of 5.00 mgkg(-1) in H. incana flowers). There were significant positive correlations between total Tl in soil and Tl in both plant species. Transfer Coefficients (TC) for all elements were, in general, <1 for both species, except for Tl in flowers and fruits at some sites. The highest Enrichment Factor (EF) was found for Tl in H. incana fruits (EF = 607) and D. catholica flowers (EF = 321). H. incana was studied in a previous growing season (2004) in the same area, although the rainfall was 3 times more than in the year of the present study (2005), giving a maximum Tl content of 46.5 mgkg(-1) in H. incana flowers. The data presented here show that Tl content of plants growing in semi-arid conditions can be significantly influenced by precipitation. In dry years, plant Tl accumulation may be significantly reduced. PMID:17123576

  16. A Spontaneous Missense Mutation in Branched Chain Keto Acid Dehydrogenase Kinase in the Rat Affects Both the Central and Peripheral Nervous Systems.

    PubMed

    Zigler, J Samuel; Hodgkinson, Colin A; Wright, Megan; Klise, Andrew; Sundin, Olof; Broman, Karl W; Hejtmancik, Fielding; Huang, Hao; Patek, Bonnie; Sergeev, Yuri; Hose, Stacey; Brayton, Cory; Xaiodong, Jiao; Vasquez, David; Maragakis, Nicholas; Mori, Susumu; Goldman, David; Hoke, Ahmet; Sinha, Debasish

    2016-01-01

    A novel mutation, causing a phenotype we named frogleg because its most obvious characteristic is a severe splaying of the hind limbs, arose spontaneously in a colony of Sprague-Dawley rats. Frogleg is a complex phenotype that includes abnormalities in hind limb function, reduced brain weight with dilated ventricles and infertility. Using micro-satellite markers spanning the entire rat genome, the mutation was mapped to a region of rat chromosome 1 between D1Rat131 and D1Rat287. Analysis of whole genome sequencing data within the linkage interval, identified a missense mutation in the branched-chain alpha-keto dehydrogenase kinase (Bckdk) gene. The protein encoded by Bckdk is an integral part of an enzyme complex located in the mitochondrial matrix of many tissues which regulates the levels of the branched-chain amino acids (BCAAs), leucine, isoleucine and valine. BCAAs are essential amino acids (not synthesized by the body), and circulating levels must be tightly regulated; levels that are too high or too low are both deleterious. BCKDK phosphorylates Ser293 of the E1α subunit of the BCKDH protein, which catalyzes the rate-limiting step in the catabolism of the BCAAs, inhibiting BCKDH and thereby, limiting breakdown of the BCAAs. In contrast, when Ser293 is not phosphorylated, BCKDH activity is unchecked and the levels of the BCAAs will decrease dramatically. The mutation is located within the kinase domain of Bckdk and is predicted to be damaging. Consistent with this, we show that in rats homozygous for the mutation, phosphorylation of BCKDH in the brain is markedly decreased relative to wild type or heterozygous littermates. Further, circulating levels of the BCAAs are reduced by 70-80% in animals homozygous for the mutation. The frogleg phenotype shares important characteristics with a previously described Bckdk knockout mouse and with human subjects with Bckdk mutations. In addition, we report novel data regarding peripheral neuropathy of the hind limbs

  17. When locomotion is used to interact with the environment: investigation of the link between emotions and the twofold goal-directed locomotion in humans.

    PubMed

    Vernazza-Martin, S; Longuet, S; Damry, T; Chamot, J M; Dru, V

    2015-10-01

    Walking as a means to interact with the environment has a twofold goal: body displacement (intermediate goal) and the future action on the environment (final representational goal). This involves different processes that plan, program, and control goal-directed locomotion linked to motivation as an "emotional state," which leads to achieving this twofold goal. The aim of the present study was to determine whether emotional valence associated with the final representational goal influences these processes or whether they depend more on the emotional valence associated with the intermediate goal in young adults. Twenty subjects, aged 18-35 years, were instructed to erase an emotional picture that appeared on a wall as soon as they saw it. They had to press a stop button located 5 m in front of them with their right hand. Their gait was analyzed using a force platform and the Vicon system. The main results suggest that the emotional valence of the intermediate goal has the greatest effect on the processes that organize and modulate goal-directed locomotion. A positive valence facilitates cognitive processes involved in the temporal organization of locomotion. A negative valence disturbs the cognitive processes involved in the spatial organization of the locomotion and online motor control, leading to a deviating trajectory and a final body position that is more distant from the stop button. These results are discussed in line with the motivational direction hypothesis and with the affective meaning of the intended response goal. PMID:26126802

  18. Relation between observed locomotion traits and locomotion score in dairy cows.

    PubMed

    Schlageter-Tello, Andrés; Bokkers, Eddie A M; Groot Koerkamp, Peter W G; Van Hertem, Tom; Viazzi, Stefano; Romanini, Carlos E B; Halachmi, Ilan; Bahr, Claudia; Berckmans, Daniël; Lokhorst, Kees

    2015-12-01

    Lameness is still an important problem in modern dairy farming. Human observation of locomotion, by looking at different traits in one go, is used in practice to assess locomotion. The objectives of this article were to determine which individual locomotion traits are most related to locomotion scores in dairy cows, and whether experienced raters are capable of scoring these individual traits consistently. Locomotion and 5 individual locomotion traits (arched back, asymmetric gait, head bobbing, reluctance to bear weight, and tracking up) were scored independently on a 5-level scale for 58 videos of different cows. Videos were shown to 10 experienced raters in 2 different scoring sessions. Relations between locomotion score and traits were estimated by 3 logistic regression models aiming to calculate the size of the fixed effects on the probability of scoring a cow in 1 of the 5 levels of the scale (model 1) and the probability of classifying a cow as lame (locomotion score ≥3; model 2) or as severely lame (locomotion score ≥4; model 3). Fixed effects were rater, session, traits, and interactions among fixed effects. Odds ratios were calculated to estimate the relative probability to classify a cow as lame when an altered (trait score ≥3) or severely altered trait (trait score ≥4) was present. Overall intrarater and interrater reliability and agreement were calculated as weighted kappa coefficient (κw) and percentage of agreement, respectively. Specific intrarater and interrater agreement for individual levels within a 5-level scale were calculated. All traits were significantly related to the locomotion score when scored with a 5-level scale and when classified as (severely) lame or nonlame. Odds ratios for altered and severely altered traits were 10.8 and 14.5 for reluctance to bear weight, 6.5 and 7.2 for asymmetric gait, and 4.8 and 3.2 for arched back, respectively. Raters showed substantial variation in reliability and agreement values when scoring

  19. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  20. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  1. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  2. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  3. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before... ambient air temperature is between 32 degrees and 104 degrees Fahrenheit inclusively; relative humidity is.... The observer shall not stand between the microphone and the horn. (8) Background noise shall...

  4. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before... ambient air temperature is between 32 degrees and 104 degrees Fahrenheit inclusively; relative humidity is.... The observer shall not stand between the microphone and the horn. (8) Background noise shall...

  5. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before... ambient air temperature is between 32 degrees and 104 degrees Fahrenheit inclusively; relative humidity is.... The observer shall not stand between the microphone and the horn. (8) Background noise shall...

  6. 77 FR 23159 - Locomotive Safety Standards; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... rule related to locomotive safety standards. See 77 FR 21312. The final rule established a public... safety standards and comments on such petitions. That final rule mistakenly lists FR-2009- 0095... is FRA-2009-0094. The final rule issued on April 9, 2012, incorrectly identified docket number...

  7. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before... Electrotechnical Commission (IEC) Standard 61672-1 (2002-05) for a Class 2 instrument. (2) An acoustic calibrator... with the acoustic calibrator immediately before and after compliance tests. Any change in the...

  8. Learning in the Development of Infant Locomotion.

    ERIC Educational Resources Information Center

    Adolph, Karen E.

    1997-01-01

    Examined how infants acquire adaptive locomotion in the novel task of going up and down slopes. Found that infants' judgments became increasingly accurate and exploration became increasingly efficient, with no transfer over the transition from crawling to walking. Infants learned to gauge their abilities on-line as they encountered each hill at…

  9. Evidence for Motor Simulation in Imagined Locomotion

    ERIC Educational Resources Information Center

    Kunz, Benjamin R.; Creem-Regehr, Sarah H.; Thompson, William B.

    2009-01-01

    A series of experiments examined the role of the motor system in imagined movement, finding a strong relationship between imagined walking performance and the biomechanical information available during actual walking. Experiments 1 through 4 established the finding that real and imagined locomotion differ in absolute walking time. We then tested…

  10. Energetics and mechanics for partial gravity locomotion.

    PubMed

    Newman, D J; Alexander, H L; Webbon, B W

    1994-09-01

    The role of gravitational acceleration on human locomotion is not clearly understood. It is hypothesized that the mechanics and energetics of locomotion depend upon the prevailing gravity level. A unique human-rated underwater treadmill and an adjustable ballasting harness were used to stimulate partial gravity environments. This study has two research aspects, biomechanics and energetics. Vertical forces which are exerted by subjects on the treadmill-mounted, split-plate force platform show that peak vertical force and stride frequency significantly decrease (p < 0.05) as the gravity level is reduced, while ground contact time is independent of gravity level. A loping gait is employed over a wide range of speeds (approximately 1.5 m/s to approximately 2.3 m/s) suggesting a change in the mechanics for lunar (1/6 G) and Martian (3/8 G) locomotion. As theory predicts, locomotion energy requirements for partial gravity levels are significantly less than at 1 G (p < 0.05). PMID:7818450

  11. The role of locomotion in psychological development

    PubMed Central

    Anderson, David I.; Campos, Joseph J.; Witherington, David C.; Dahl, Audun; Rivera, Monica; He, Minxuan; Uchiyama, Ichiro; Barbu-Roth, Marianne

    2013-01-01

    The psychological revolution that follows the onset of independent locomotion in the latter half of the infant's first year provides one of the best illustrations of the intimate connection between action and psychological processes. In this paper, we document some of the dramatic changes in perception-action coupling, spatial cognition, memory, and social and emotional development that follow the acquisition of independent locomotion. We highlight the range of converging research operations that have been used to examine the relation between locomotor experience and psychological development, and we describe recent attempts to uncover the processes that underlie this relation. Finally, we address three important questions about the relation that have received scant attention in the research literature. These questions include: (1) What changes in the brain occur when infants acquire experience with locomotion? (2) What role does locomotion play in the maintenance of psychological function? (3) What implications do motor disabilities have for psychological development? Seeking the answers to these questions can provide rich insights into the relation between action and psychological processes and the general processes that underlie human development. PMID:23888146

  12. 30 CFR 57.6203 - Locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Locomotives. 57.6203 Section 57.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6203...

  13. 30 CFR 57.6203 - Locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Locomotives. 57.6203 Section 57.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6203...

  14. 30 CFR 57.6203 - Locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Locomotives. 57.6203 Section 57.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6203...

  15. 30 CFR 57.6203 - Locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Locomotives. 57.6203 Section 57.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6203...

  16. 30 CFR 57.6203 - Locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Locomotives. 57.6203 Section 57.6203 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface and Underground § 57.6203...

  17. Lizard locomotion in heterogeneous granular media

    NASA Astrophysics Data System (ADS)

    Schiebel, Perrin; Goldman, Daniel

    2014-03-01

    Locomotion strategies in heterogeneous granular environments (common substrates in deserts), are relatively unexplored. The zebra-tailed lizard (C. draconoides) is a useful model organism for such studies owing to its exceptional ability to navigate a variety of desert habitats at impressive speed (up to 50 body-lengths per second) using both quadrapedal and bidepal gaits. In laboratory experiments, we challenge the lizards to run across a field of boulders (2.54 cm diameter glass spheres or 3.8 cm 3D printed spheres) placed in a lattice pattern and embedded in a loosely packed granular medium of 0.3 mm diameter glass particles. Locomotion kinematics of the lizard are recorded using high speed cameras, with and without the scatterers. The data reveals that unlike the lizard's typical quadrupedal locomotion using a diagonal gait, when scatterers are present the lizard is most successful when using a bipedal gait, with a raised center of mass (CoM). We propose that the kinematics of bipedal running in conjunction with the lizard's long toes and compliant hind foot are the keys to this lizard's successful locomotion in the presence of such obstacles. NSF PoLS

  18. Judgments of Path, Not Heading, Guide Locomotion

    ERIC Educational Resources Information Center

    Wilkie, Richard M.; Wann, John P.

    2006-01-01

    To steer a course through the world, people are almost entirely dependent on visual information, of which a key component is optic flow. In many models of locomotion, heading is described as the fundamental control variable; however, it has also been shown that fixating points along or near one's future path could be the basis of an efficient…

  19. Passive mechanics in jellyfish-like locomotion

    NASA Astrophysics Data System (ADS)

    Wilson, Megan; Eldredge, Jeff

    2008-11-01

    The aim of this work is to identify possible benefits of passive flexibility in biologically-inspired locomotion. Substantial energy savings are likely achieved in natural locomotion by allowing a mix of actively controlled and passively responsive deformation. The jellyfish is a useful target of study, due to its relatively simple structure and the availability of recent kinematics and flow-field measurements. In this investigation, the jellyfish consists of a two-dimensional articulated system of rigid bodies linked by hinges. The kinematics -- expressed via the hinge angles -- are adapted from experimentally measured motion. The free swimming system is explored via high-fidelity numerical simulation with a viscous vortex particle method with coupled body dynamics. The computational tool allows the arbitrary designation of individual hinges as ``active'' or ``passive,'' to introduce a mix of flexibility into the system. In some cases, replacing an active hinge with a passive spring can enhance the mean swimming speed, thus reducing the power requirements of the system. Varying the stiffness and damping coefficients of the spring yield different locomotive results. The numerical solution is used to compute the finite-time Lyapunov exponents (FTLE) throughout the field. The FTLE fields reveal manifolds in the flow that act as transport barriers, uncovering otherwise unseen geometric characteristics of the flow field that add new insight into the locomotion mechanics.

  20. 49 CFR 229.207 - New locomotive crashworthiness design standards and changes to existing FRA-approved locomotive...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-approved locomotive crashworthiness design standards. (a) General. The following procedures govern... approval of a locomotive crashworthiness design standard must be titled “Petition for FRA Approval of a New... petition for approval of a substantive change to an FRA-approved locomotive crashworthiness design...

  1. 49 CFR 1242.60 - Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives (accounts XX-51-67, XX-51-68 and XX-51-69). 1242.60 Section...-Transportation § 1242.60 Locomotive fuel, electric power purchased/produced for motive power and...

  2. 49 CFR 229.207 - New locomotive crashworthiness design standards and changes to existing FRA-approved locomotive...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false New locomotive crashworthiness design standards... Design Requirements § 229.207 New locomotive crashworthiness design standards and changes to existing FRA... consideration and action upon requests for FRA approval of new locomotive crashworthiness design standards...

  3. 49 CFR 1242.60 - Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives (accounts XX-51-67, XX-51-68 and XX-51-69). 1242.60 Section...-Transportation § 1242.60 Locomotive fuel, electric power purchased/produced for motive power and...

  4. Kinetics of bipedal locomotion during load carrying in capuchin monkeys.

    PubMed

    Hanna, Jandy B; Schmitt, Daniel; Wright, Kristin; Eshchar, Yonat; Visalberghi, Elisabetta; Fragaszy, Dorothy

    2015-08-01

    Facultative bipedalism during load transport in nonhuman primates has been argued to be an important behavior potentially leading to the evolution of obligate, extended limb bipedalism. Understanding the biomechanics of such behavior may lead to insights about associated morphology, which may translate to interpretation of features in the fossil record. Some populations of bearded capuchin monkeys (Sapajus libidinosus) spontaneously carry heavy loads bipedally during foraging activities. This study provides the first data on all three components of ground reaction force for spontaneous bipedalism during load carriage in a nonhuman primate. Five individual S. libidinosus (mean body mass = 2.4 kg ± 0.96) were videorecorded during bipedalism while carrying a stone (0.93 kg) under natural conditions. A force plate was embedded in the path of the monkeys. Spatiotemporal and force data for all three components of the ground reaction force were recorded for 28 steps. Capuchins exhibited a mean vertical peak force per total weight (Vpk) for the hindlimb of 1.19 (sd = 0.13), consistent with those of unloaded capuchins in the laboratory and for other bipedal primates, including humans. Vertical force records suggest that capuchins, along with most nonhuman primates, maintain a relatively compliant leg during both unloaded and loaded locomotion. Like all other primates, loaded capuchins maintained laterally (outward) directed medio-lateral forces, presumably to stabilize side-to-side movements of the center of mass. Medio-lateral forces suggest that at near-running speeds dynamic stability diminishes the need to generate high lateral forces. Vertical force traces exhibited a measurable impact spike at foot contact in 85% of the steps recorded. An impact spike is common in human walking and running but has not been reported in other bipedal primates. This spike in humans is thought to lead to bone and cartilage damage. The earliest biped may have experienced similar

  5. Delayed and lasting effects of deep brain stimulation on locomotion in Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Beuter, Anne; Modolo, Julien

    2009-06-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by a variety of motor signs affecting gait, postural stability, and tremor. These symptoms can be improved when electrodes are implanted in deep brain structures and electrical stimulation is delivered chronically at high frequency (>100 Hz). Deep brain stimulation (DBS) onset or cessation affects PD signs with different latencies, and the long-term improvements of symptoms affecting the body axis and those affecting the limbs vary in duration. Interestingly, these effects have not been systematically analyzed and modeled. We compare these timing phenomena in relation to one axial (i.e., locomotion) and one distal (i.e., tremor) signs. We suggest that during DBS, these symptoms are improved by different network mechanisms operating at multiple time scales. Locomotion improvement may involve a delayed plastic reorganization, which takes hours to develop, whereas rest tremor is probably alleviated by an almost instantaneous desynchronization of neural activity in subcortical structures. Even if all PD patients develop both distal and axial symptoms sooner or later, current computational models of locomotion and rest tremor are separate. Furthermore, a few computational models of locomotion focus on PD and none exploring the effect of DBS was found in the literature. We, therefore, discuss a model of a neuronal network during DBS, general enough to explore the subcircuits controlling locomotion and rest tremor simultaneously. This model accounts for synchronization and plasticity, two mechanisms that are believed to underlie the two types of symptoms analyzed. We suggest that a hysteretic effect caused by DBS-induced plasticity and synchronization modulation contributes to the different therapeutic latencies observed. Such a comprehensive, generic computational model of DBS effects, incorporating these timing phenomena, should assist in developing a more efficient, faster, durable treatment of

  6. Locomotion and drag in wet and dry granular media

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel; Kuckuk, Robyn; Sharpe, Sarah

    2015-03-01

    Many animals move within substrates such as soil and dry sand; the resistive properties of such granular materials (GM) can depend on water content and compaction, but little is known about how such parameters affect locomotion or the relevant physics of drag and penetration. We developed a system to create homogeneous wet GM of varying moisture content and compaction in quantities sufficient to study the burial and subsurface locomotion of the Ocellated skink (C. ocellatus) a desert-generalist lizard. X-ray imaging revealed that in wet and dry GM the lizard slowly buried (~ 30 seconds) propagating a wave from head to tail, while moving in a start-stop motion. During forward movement, the head oscillated, and the forelimb on the convex side of the body propelled the animal. Although body kinematics (and ``slip'') were similar in both substrates, the burial depth was smaller in wet GM. Penetration and drag force experiments on smooth cylinders revealed that wet GM was ~ 3 × more resistive than dry GM, suggesting that during burial the lizard operated near its maximum force producing capability and was thus constrained by environmental properties. work supported by NSF PoLS.

  7. Receptors and Other Signaling Proteins Required for Serotonin Control of Locomotion in Caenorhabditis elegans

    PubMed Central

    Gürel, Güliz; Gustafson, Megan A.; Pepper, Judy S.; Horvitz, H. Robert; Koelle, Michael R.

    2012-01-01

    A better understanding of the molecular mechanisms of signaling by the neurotransmitter serotonin is required to assess the hypothesis that defects in serotonin signaling underlie depression in humans. Caenorhabditis elegans uses serotonin as a neurotransmitter to regulate locomotion, providing a genetic system to analyze serotonin signaling. From large-scale genetic screens we identified 36 mutants of C. elegans in which serotonin fails to have its normal effect of slowing locomotion, and we molecularly identified eight genes affected by 19 of the mutations. Two of the genes encode the serotonin-gated ion channel MOD-1 and the G-protein-coupled serotonin receptor SER-4. mod-1 is expressed in the neurons and muscles that directly control locomotion, while ser-4 is expressed in an almost entirely non-overlapping set of sensory and interneurons. The cells expressing the two receptors are largely not direct postsynaptic targets of serotonergic neurons. We analyzed animals lacking or overexpressing the receptors in various combinations using several assays for serotonin response. We found that the two receptors act in parallel to affect locomotion. Our results show that serotonin functions as an extrasynaptic signal that independently activates multiple receptors at a distance from its release sites and identify at least six additional proteins that appear to act with serotonin receptors to mediate serotonin response. PMID:23023001

  8. Anticipatory control using substrate manipulation enables trajectory control of legged locomotion on heterogeneous granular media

    NASA Astrophysics Data System (ADS)

    Qian, Feifei; Goldman, Daniel

    2015-05-01

    Legged robots must traverse complex terrain consisting of particles of varying size, shape and texture. While much is known about how robots can effectively locomote on hard ground and increasingly on homogeneous granular media, principles of locomotion over heterogeneous granular substrates are relatively unexplored. To systematically discover how substrate heterogeneity affects ambulatory locomotion, we investigate how the presence of a single boulder (3D printed convex objects of different geometries) embedded in fine granular media affects the trajectory of a small (150 g) six legged robot. Using an automated system to collect thousands of locomotion trials, we observed that trajectories were straight before the interaction with the boulder, and scattered to different angles after the interaction depending on the leg-boulder contact positions. However, this dependence of scattering angle upon contact zone was relatively insensitive to boulder shape, orientation and roughness.1 Inspired by this insensitivity, here we develop an anticipatory control scheme which uses the scattering information in coordination with a tail induced substrate jamming. Our scheme allows the robot to "envision" outcomes of the interaction such that the robot can prevent trajectory deviation before the scattering occurs. We hypothesize that (particularly during rapid running or in the presence of noisy sensors) appropriate substrate manipulation can allow a robot to remain in a favorable locomotor configuration and avoid catastrophic interactions.

  9. Loss of signal transduction and inhibition of lymphocyte locomotion in a ground-based model of microgravity

    NASA Technical Reports Server (NTRS)

    Sundaresan, Alamelu; Risin, Diana; Pellis, Neal R.; McIntire, L. V. (Principal Investigator)

    2002-01-01

    Inflammatory adherence to, and locomotion through the interstitium is an important component of the immune response. Conditions such as microgravity and modeled microgravity (MMG) severely inhibit lymphocyte locomotion in vitro through gelled type I collagen. We used the NASA rotating wall vessel bioreactor or slow-turning lateral vessel as a prototype for MMG in ground-based experiments. Previous experiments from our laboratory revealed that when lymphocytes (human peripheral blood mononuclear cells [PBMCs]) were first activated with phytohemaglutinin followed by exposure to MMG, locomotory capacity was not affected. In the present study, MMG inhibits lymphocyte locomotion in a manner similar to that observed in microgravity. Phorbol myristate acetate (PMA) treatment of PBMCs restored lost locomotory capacity by a maximum of 87%. Augmentation of cellular calcium flux with ionomycin had no restorative effect. Treatment of lymphocytes with mitomycin C prior to exposure to MMG, followed by PMA, restored locomotion to the same extent as when nonmitomycin C-treated lymphocytes were exposed to MMG (80-87%), suggesting that deoxyribonucleic acid replication is not essential for the restoration of locomotion. Thus, direct activation of protein kinase C (PKC) with PMA was effective in restoring locomotion in MMG comparable to the normal levels seen in Ig cultures. Therefore, in MMG, lymphocyte calcium signaling pathways were functional, with defects occurring at either the level of PKC or upstream of PKC.

  10. Abstracting in the Context of Spontaneous Learning

    ERIC Educational Resources Information Center

    Williams, Gaye

    2007-01-01

    There is evidence that spontaneous learning leads to relational understanding and high positive affect. To study spontaneous abstracting, a model was constructed by combining the RBC model of abstraction with Krutetskii's mental activities. Using video-stimulated interviews, the model was then used to analyze the behavior of two Year 8 students…

  11. Locomotion control of hybrid cockroach robots

    PubMed Central

    Sanchez, Carlos J.; Chiu, Chen-Wei; Zhou, Yan; González, Jorge M.; Vinson, S. Bradleigh; Liang, Hong

    2015-01-01

    Natural systems retain significant advantages over engineered systems in many aspects, including size and versatility. In this research, we develop a hybrid robotic system using American (Periplaneta americana) and discoid (Blaberus discoidalis) cockroaches that uses the natural locomotion and robustness of the insect. A tethered control system was firstly characterized using American cockroaches, wherein implanted electrodes were used to apply an electrical stimulus to the prothoracic ganglia. Using this approach, larger discoid cockroaches were engineered into a remotely controlled hybrid robotic system. Locomotion control was achieved through electrical stimulation of the prothoracic ganglia, via a remotely operated backpack system and implanted electrodes. The backpack consisted of a microcontroller with integrated transceiver protocol, and a rechargeable battery. The hybrid discoid roach was able to walk, and turn in response to an electrical stimulus to its nervous system with high repeatability of 60%. PMID:25740855

  12. Locomotion control of hybrid cockroach robots.

    PubMed

    Sanchez, Carlos J; Chiu, Chen-Wei; Zhou, Yan; González, Jorge M; Vinson, S Bradleigh; Liang, Hong

    2015-04-01

    Natural systems retain significant advantages over engineered systems in many aspects, including size and versatility. In this research, we develop a hybrid robotic system using American (Periplaneta americana) and discoid (Blaberus discoidalis) cockroaches that uses the natural locomotion and robustness of the insect. A tethered control system was firstly characterized using American cockroaches, wherein implanted electrodes were used to apply an electrical stimulus to the prothoracic ganglia. Using this approach, larger discoid cockroaches were engineered into a remotely controlled hybrid robotic system. Locomotion control was achieved through electrical stimulation of the prothoracic ganglia, via a remotely operated backpack system and implanted electrodes. The backpack consisted of a microcontroller with integrated transceiver protocol, and a rechargeable battery. The hybrid discoid roach was able to walk, and turn in response to an electrical stimulus to its nervous system with high repeatability of 60%. PMID:25740855

  13. Intermittent locomotion as an optimal control strategy

    PubMed Central

    Paoletti, P.; Mahadevan, L.

    2014-01-01

    Birds, fish and other animals routinely use unsteady effects to save energy by alternating between phases of active propulsion and passive coasting. Here, we construct a minimal model for such behaviour that can be couched as an optimal control problem via an analogy to travelling with a rechargeable battery. An analytical solution of the optimal control problem proves that intermittent locomotion has lower energy requirements relative to steady-state strategies. Additional realistic hypotheses, such as the assumption that metabolic cost at a given power should be minimal (the fixed gear hypothesis), a nonlinear dependence of the energy storage rate on propulsion and/or a preferred average speed, allow us to generalize the model and demonstrate the flexibility of intermittent locomotion with implications for biological and artificial systems. PMID:24711718

  14. Locomotion of chemically powered autonomous nanowire motors

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Li, Longqiu; Li, Tianlong; Zhang, Guangyu; Sun, Qian

    2015-08-01

    Physical insights on the hydrodynamics and locomotion of self-propelled nanowire motor under nonequilibrium steady state are investigated using finite element method in accordance with hybrid molecular dynamics/multiparticle collision dynamics and rigid body dynamics. Nanowire motor is discretized into finite segments, and forces of solvent molecule acting on the motor are assumed to be the sum of forces acting on all segments of the motor. We show that the locomotion of nanowire motor is mainly determined by the imbalance forces acting on the catalytic and noncatalytic segments. The average velocity along the axis increases significantly as a function of time prior to reaching equilibrium. The length of nanowire motor shows negligible effect on the velocity of the motor. Preliminary experimental results are provided to validate the current model.

  15. Both dorsal and ventral spinal cord pathways contribute to overground locomotion in the adult rat.

    PubMed

    Loy, David N; Talbott, Jason F; Onifer, Stephen M; Mills, Michael D; Burke, Darlene A; Dennison, Jessica B; Fajardo, Lili C; Magnuson, David S K; Whittemore, Scott R

    2002-10-01

    Identification of long tracts responsible for spontaneous locomotion is critical for spinal cord injury (SCI) repair strategies. We recently demonstrated that extensive demyelination of adult rat thoracic ventral columns, ventromedial, and ventrolateral white matter produces persistent, significant open-field hindlimb locomotor deficits. Locomotor movements resulting from stimulation of the pontomedullary locomotor region are inhibited by dorsolateral funiculus (DLF) lesions suggesting that important pathways for locomotion may also exist in the dorsal white matter. However, dorsal hemisections that interrupt dorsal columns/dorsal corticospinal tract (DC/CST) and DLF pathways do not produce persistent, severe locomotor deficits in the adult rat. We studied the contributions of myelinated tracts in the DLF and DC/CST to overground locomotion following complete conduction blockade of axons in the ventrolateral funiculus (VLF), a region important for locomotor movements and for transcranial magnetic motor-evoked potentials (tcMMEP). Animals received ethidium bromide plus photon irradiation to produce discrete demyelinating lesions sufficient to stop axonal conduction in the VLF, combined VLF + DLF, or combined VLF + DC/CST. Open-field BBB scores and tcMMEPs were studied at 1, 2, 3, and 4 weeks postlesion. VLF lesions resulted in mean BBB scores of 17 at 4 weeks. VLF + DC/CST and VLF + DLF lesions resulted in mean BBB scores of 15.9 and 11.1, respectively. TcMMEPs were absent in all lesion types confirming VLF conduction blockade throughout the study. Our data indicate that significant contributions to locomotion from myelinated pathways within the rat DLF can be revealed when combined with simultaneous compromise of the VLF. PMID:12429203

  16. Characterization of a Spontaneous Novel Mutation in the NPC2 Gene in a Cat Affected by Niemann Pick Type C Disease

    PubMed Central

    Zampieri, Stefania; Bianchi, Ezio; Cantile, Carlo; Saleri, Roberta; Bembi, Bruno; Dardis, Andrea

    2014-01-01

    Niemann-Pick C disease (NPC) is an autosomal recessive lysosomal storage disorder characterized by accumulation of unesterified cholesterol and other lipids within the lysosomes due to mutation in NPC1 or NPC2 genes. A feline model of NPC carrying a mutation in NPC1 gene has been previously described. We have identified two kittens affected by NPC disease due to a mutation in NPC2 gene. They manifested with tremors at the age of 3 months, which progressed to dystonia and severe ataxia. At 6 months of age cat 2 was unable to stand without assistance and had bilaterally reduced menace response. It died at the age of 10 months. Post-mortem histological analysis of the brain showed the presence of neurons with cytoplasmic swelling and vacuoles, gliosis of the substantia nigra and degeneration of the white matter. Spheroids with accumulation of ubiquitinated aggregates were prominent in the cerebellar cortex. Purkinje cells were markedly reduced in number and they showed prominent intracytoplasmic storage. Scattered perivascular aggregates of lymphocytes and microglial cells proliferation were present in the thalamus and midbrain. Proliferation of Bergmann glia was also observed. In the liver, hepatocytes were swollen because of accumulation of small vacuoles and foamy Kupffer cells were also detected. Foamy macrophages were observed within the pulmonary interstitium and alveoli as well. At 9 months cat 1 was unable to walk, developed seizures and it was euthanized at 21 months. Filipin staining of cultured fibroblasts showed massive storage of unesterified cholesterol. Molecular analysis of NPC1 and NPC2 genes showed the presence of a homozygous intronic mutation (c.82+5G>A) in the NPC2 gene. The subsequent analysis of the mRNA showed that the mutation causes the retention of 105 bp in the mature mRNA, which leads to the in frame insertion of 35 amino acids between residues 28 and 29 of NPC2 protein (p.G28_S29ins35). PMID:25396745

  17. Disparity and convergence in bipedal archosaur locomotion

    PubMed Central

    Bates, K. T.; Schachner, E. R.

    2012-01-01

    This study aims to investigate functional disparity in the locomotor apparatus of bipedal archosaurs. We use reconstructions of hindlimb myology of extant and extinct archosaurs to generate musculoskeletal biomechanical models to test hypothesized convergence between bipedal crocodile-line archosaurs and dinosaurs. Quantitative comparison of muscle leverage supports the inference that bipedal crocodile-line archosaurs and non-avian theropods had highly convergent hindlimb myology, suggesting similar muscular mechanics and neuromuscular control of locomotion. While these groups independently evolved similar musculoskeletal solutions to the challenges of parasagittally erect bipedalism, differences also clearly exist, particularly the distinct hip and crurotarsal ankle morphology characteristic of many pseudosuchian archosaurs. Furthermore, comparative analyses of muscle design in extant archosaurs reveal that muscular parameters such as size and architecture are more highly adapted or optimized for habitual locomotion than moment arms. The importance of these aspects of muscle design, which are not directly retrievable from fossils, warns against over-extrapolating the functional significance of anatomical convergences. Nevertheless, links identified between posture, muscle moments and neural control in archosaur locomotion suggest that functional interpretations of osteological changes in limb anatomy traditionally linked to postural evolution in Late Triassic archosaurs could be constrained through musculoskeletal modelling. PMID:22112652

  18. The effect of routine hoof trimming on locomotion score, ruminating time, activity, and milk yield of dairy cows.

    PubMed

    Van Hertem, T; Parmet, Y; Steensels, M; Maltz, E; Antler, A; Schlageter-Tello, A A; Lokhorst, C; Romanini, C E B; Viazzi, S; Bahr, C; Berckmans, D; Halachmi, I

    2014-01-01

    The objective of this study was to quantify the effect of hoof trimming on cow behavior (ruminating time, activity, and locomotion score) and performance (milk yield) over time. Data were gathered from a commercial dairy farm in Israel where routine hoof trimming is done by a trained hoof trimmer twice per year on the entire herd. In total, 288 cows spread over 6 groups with varying production levels were used for the analysis. Cow behavior was measured continuously with a commercial neck activity logger and a ruminating time logger (HR-Tag, SCR Engineers Ltd., Netanya, Israel). Milk yield was recorded during each milking session with a commercial milk flow sensor (Free Flow, SCR Engineers Ltd.). A trained observer assigned on the spot 5-point locomotion scores during 19 nighttime milking occasions between 22 October 2012 and 4 February 2013. Behavioral and performance data were gathered from 1wk before hoof trimming until 1wk after hoof trimming. A generalized linear mixed model was used to statistically test all main and interactive effects of hoof trimming, parity, lactation stage, and hoof lesion presence on ruminating time, neck activity, milk yield, and locomotion score. The results on locomotion scores show that the proportional distribution of cows in the different locomotion score classes changes significantly after trimming. The proportion of cows with a locomotion score ≥3 increases from 14% before to 34% directly after the hoof trimming. Two months after the trimming, the number of cows with a locomotion score ≥3 reduced to 20%, which was still higher than the baseline values 2wk before the trimming. The neck activity level was significantly reduced 1d after trimming (380±6 bits/d) compared with before trimming (389±6 bits/d). Each one-unit increase in locomotion score reduced cow activity level by 4.488 bits/d. The effect of hoof trimming on ruminating time was affected by an interaction effect with parity. The effect of hoof trimming on

  19. Terrain Classification From Body-Mounted Cameras During Human Locomotion.

    PubMed

    Anantrasirichai, Nantheera; Burn, Jeremy; Bull, David

    2015-10-01

    This paper presents a novel algorithm for terrain type classification based on monocular video captured from the viewpoint of human locomotion. A texture-based algorithm is developed to classify the path ahead into multiple groups that can be used to support terrain classification. Gait is taken into account in two ways. Firstly, for key frame selection, when regions with homogeneous texture characteristics are updated, the frequency variations of the textured surface are analyzed and used to adaptively define filter coefficients. Secondly, it is incorporated in the parameter estimation process where probabilities of path consistency are employed to improve terrain-type estimation. When tested with multiple classes that directly affect mobility-a hard surface, a soft surface, and an unwalkable area-our proposed method outperforms existing methods by up to 16%, and also provides improved robustness. PMID:25420277

  20. Caenorhabditis elegans exhibit a coupling between the defecation motor program and directed locomotion

    PubMed Central

    Nagy, Stanislav; Huang, Yung-Chi; Alkema, Mark J.; Biron, David

    2015-01-01

    Distinct motor programs can be coupled to refine the repertoire of behavior dynamics. However, mechanisms underlying such coupling are poorly understood. The defecation motor program (DMP) of C. elegans is composed of a succession of body contraction and expulsion steps, performed repeatedly with a period of 50–60 sec. We show that recurring patterns of directed locomotion are executed in tandem with, co-reset, and co-terminate with the DMP cycle. Calcium waves in the intestine and proton signaling were shown to regulate the DMP. We found that genetic manipulations affecting these calcium dynamics regulated the corresponding patterns of directed locomotion. Moreover, we observed the initiation of a recurring locomotion pattern 10 seconds prior to the posterior body contraction, suggesting that the synchronized motor program may initiate prior to the DMP. This study links two multi-step motor programs executed by C. elegans in synchrony, utilizing non-neuronal tissue to drive directed locomotion. PMID:26597056

  1. Interplay between shear stress and adhesion on neutrophil locomotion.

    PubMed

    Smith, Lee A; Aranda-Espinoza, Helim; Haun, Jered B; Hammer, Daniel A

    2007-01-15

    Leukocyte locomotion over the lumen of inflamed endothelial cells is a critical step, following firm adhesion, in the inflammatory response. Once firmly adherent, the cell will spread and will either undergo diapedesis through individual vascular endothelial cells or will migrate to tight junctions before extravasating to the site of injury or infection. Little is known about the mechanisms of neutrophil spreading or locomotion, or how motility is affected by the physical environment. We performed a systematic study to investigate the effect of the type of adhesive ligand and shear stress on neutrophil motility by employing a parallel-plate flow chamber with reconstituted protein surfaces of E-selectin, E-selectin/PECAM-1, and E-selectin/ICAM-1. We find that the level and type of adhesive ligand and the shear rate are intertwined in affecting several metrics of migration, such as the migration velocity, random motility, index of migration, and the percentage of cells moving in the direction of flow. On surfaces with high levels of PECAM-1, there is a near doubling in random motility at a shear rate of 180 s(-1) compared to the motility in the absence of flow. On surfaces with ICAM-1, neutrophil random motility exhibits a weaker response to shear rate, decreasing slightly when shear rate is increased from static conditions to 180 s(-1), and is only slightly higher at 1000 s(-1) than in the absence of flow. The random motility increases with increasing surface concentrations of E-selectin and PECAM-1 under static and flow conditions. Our findings illustrate that the endothelium may regulate neutrophil migration in postcapillary venules through the presentation of various adhesion ligands at sites of inflammation. PMID:17071667

  2. Industry review: Locomotive dynamic characterization test-analysis

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Data are given relative to tests performed on locomotive components. Dynamic characteristics related to safety are described. Suspension systems, shock absorbers, data processing, bearings, and damping are discussed.

  3. A contribution about ferrofluid based flow manipulation and locomotion systems

    NASA Astrophysics Data System (ADS)

    Zimmermann, K.; Zeidis, I.; Bohm, V.; Popp, J.

    2009-02-01

    With the background of developing apedal bionic inspired locomotion systems for future application fields like autonomous (swarm) robots, medical engineering and inspection systems, this article presents a selection of locomotion systems with bifluidic flow control using ferrofluid. By controlling the change of shape, position and pressure of the ferrofluid in a secondary low viscous fluid by magnetic fields locomotion of objects or the ferrofluid itself can be realised. The locomotion of an object is caused in the first example by a ferrofluid generated flow of the secondary fluid and in the second and third case by the direct alteration of the ferrofluid position.

  4. The Need for Speed in Rodent Locomotion Analyses

    PubMed Central

    Batka, Richard J.; Brown, Todd J.; Mcmillan, Kathryn P.; Meadows, Rena M.; Jones, Kathryn J.; Haulcomb, Melissa M.

    2016-01-01

    Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript, we accomplish three things: (1) review the interaction between speed and locomotion variables in rodent studies, (2) comprehensively analyze the relationship between speed and 162 locomotion variables in a group of 16 wild-type mice using the CatWalk gait analysis system, and (3) develop and test a statistical method in which locomotion variables are analyzed and reported in the context of speed. Notable results include the following: (1) over 90% of variables, reported by CatWalk, were dependent on speed with an average R2 value of 0.624, (2) most variables were related to speed in a nonlinear manner, (3) current methods of controlling for speed are insufficient, and (4) the linear mixed model is an appropriate and effective statistical method for locomotion analyses that is inclusive of speed-dependent relationships. Given the pervasive dependency of locomotion variables on speed, we maintain that valid conclusions from locomotion analyses cannot be made unless they are analyzed and reported within the context of speed. PMID:24890845

  5. The equine neck and its function during movement and locomotion.

    PubMed

    Zsoldos, Rebeka R; Licka, Theresia F

    2015-10-01

    During both locomotion and body movements at stance, the head and neck of the horse are a major craniocaudal and lateral balancing mechanism employing input from the visual, vestibular and proprioceptive systems. The function of the equine neck has recently become the focus of several research groups; this is probably also feeding on an increase of interest in the equine neck in equestrian sports, with a controversial discussion of specific neck positions such as maximum head and neck flexion. The aim of this review is to offer an overview of new findings on the structures and functions of the equine neck, illustrating their interplay. The movement of the neck is based on intervertebral motion, but it is also an integral part of locomotion; this is illustrated by the different neck conformations in the breeds of horses used for various types of work. The considerable effect of the neck movement and posture onto the whole trunk and even the limbs is transmitted via bony, ligamentous and muscular structures. Also, the fact that the neck position can easily be influenced by the rider and/or by the employment of training aids makes it an important avenue for training of new movements of the neck as well as the whole horse. Additionally, the neck position also affects the cervical spinal cord as well as the roots of the spinal nerves; besides the commonly encountered long-term neurological effects of cervical vertebral disorders, short-term changes of neural and muscular function have also been identified in the maximum flexion of the cranial neck and head position. During locomotion, the neck stores elastic energy within the passive tissues such as ligaments, joint capsules and fasciae. For adequate stabilisation, additional muscle activity is necessary; this is learned and requires constant muscle training as it is essential to prevent excessive wear and tear on the vertebral joints and also repetitive or single trauma to the spinal nerves and the spinal cord. The

  6. Optimal locomotion of mechanical rectifier systems

    NASA Astrophysics Data System (ADS)

    Blair, Justin T.

    Vehicles utilizing animal locomotion mechanisms may possess increased performance parameters and the ability to overcome more difficult terrain than conventional wheel or propeller driven vehicles. The essential mechanism underlying animal locomotion can be viewed as mechanical rectification that converts periodic body movements to thrust force through interactions with the environment. This dissertation defines a general class of mechanical rectifiers as multi-body systems equipped with such thrust generation mechanisms. A general model is developed from the Euler-Lagrange equation and simplified by assuming small body oscillations around a given nominal posture. The model reveals that the rectifying dynamics can be captured by a bilinear (but not linear) term of body shape variables. An optimal gait problem is formulated for the bilinear rectifier model as a minimization of a quadratic cost function over the set of periodic functions subject to a constraint on the average locomotion velocity. We prove that a globally optimal solution is given by a harmonic gait that can be found by generalized eigenvalue computation with a line search over cycle frequencies. We verify the solution method through case studies of a two dimensional chain of links for which snake-like undulations and jellyfish-like flapping gaits are found to be optimal, and obtain analytical insights into determinants of optimal gaits from a simple disk-mass rectifier system. Lastly, we develop a dynamic model for batoid swimming featuring a 6 degree-of-freedom main body (position and orientation), with independent wing deformation (described as the motion of many discrete points in the body-fixed coordinate frame), and calculate various gaits. Multiple wing shapes and optimality criteria are considered, such as the maximum thrust to deflection ratio or minimum input power, and the resulting gaits are compared.

  7. Guiding locomotion in complex, dynamic environments.

    PubMed

    Fajen, Brett R

    2013-01-01

    Locomotion in complex, dynamic environments is an integral part of many daily activities, including walking in crowded spaces, driving on busy roadways, and playing sports. Many of the tasks that humans perform in such environments involve interactions with moving objects-that is, they require people to coordinate their own movement with the movements of other objects. A widely adopted framework for research on the detection, avoidance, and interception of moving objects is the bearing angle model, according to which observers move so as to keep the bearing angle of the object constant for interception and varying for obstacle avoidance. The bearing angle model offers a simple, parsimonious account of visual control but has several significant limitations and does not easily scale up to more complex tasks. In this paper, I introduce an alternative account of how humans choose actions and guide locomotion in the presence of moving objects. I show how the new approach addresses the limitations of the bearing angle model and accounts for a variety of behaviors involving moving objects, including (1) choosing whether to pass in front of or behind a moving obstacle, (2) perceiving whether a gap between a pair of moving obstacles is passable, (3) avoiding a collision while passing through single or multiple lanes of traffic, (4) coordinating speed and direction of locomotion during interception, (5) simultaneously intercepting a moving target while avoiding a stationary or moving obstacle, and (6) knowing whether to abandon the chase of a moving target. I also summarize data from recent studies that support the new approach. PMID:23885238

  8. Coal-fueled diesel locomotive test

    SciTech Connect

    Hsu, B.D.; McDowell, R.E.; Confer, G.L.; Basic, S.L.

    1993-01-01

    The biggest challenges to the development of a commercially-acceptable coal-fueled diesel-electric locomotive are integrating all systems into a working unit that can be operated in railroad service. This involves mainly the following three systems: (1) the multi-cylinder coal-fueled diesel engine, (2) the locomotive and engine controls, and (3) the CWS fuel supply system. Consequently, a workable 12-cylinder coal-fueled diesel engine was considered necessary at this stage to evolve the required locomotive support systems, in addition to gaining valuable multi-cylinder engine operating experience. The CWS fuel used during this project was obtained from Otisca, Inc. (Syracuse, NY). It was prepared from micronized and deashed Kentucky Blue Gem coal to 49.0% coal loading by weight, with less than 1% ash and 5 micron mean diameter particle size. Its higher heating value was analyzed at approximately 34630 kJ/k. Anti-agglomerating additive Triton X-114 was added to the CWS at GE Transportation Systems at 2% of coal weight. The nature of the Otisca CWS fuel makes it inherently more difficult to store, pump, and inject than diesel fuel, since concepts which govern Newtonian or normally viscous liquids do not apply entirely to CWS. Otisca CWS tends to be unstable and to settle in tanks and lines after a period of time, making it necessary to provide a means of agitation during storage. To avoid long term settling problems and to minimize losses, piping velocities were designed to be in the 60-90 m/min range.

  9. Exposure to noise on board locomotives.

    PubMed

    Seshagiri, Baily

    2003-01-01

    Personal and area noise dosimetry measurements were taken in the cabs of leading and trailing locomotives on 48 trips, under winter and summer conditions, on 9 different routes. The mean equivalent sound level (L(EQ), 3 dB exchange rate, 50 dBA threshold) of the engineers and conductors was 84 dBA during winter and 88 dBA during summer. The corresponding time-weighted average levels (L(TWA), 5 dB exchange rate, 80 dBA threshold) were 80 and 84 dBA respectively. The L(EQ) of 56% of the engineers sampled was > or =85 dBA and of 13% was > or =90 dBA. Plots of L(EQ) time history show that under normal operating conditions L(EQ) reaches its steady-state value in about 3 hours. The mean noise levels in the trailing cabs were lower than the personal exposure levels of the engineers and conductors. The mean L(EQ) on the engineer and conductor sides was 80 dBA during winter, and 85 dBA during summer. Locomotive configuration has a significant effect on the noise levels in the trailing cab. The forward-backward configuration resulted in higher noise levels than the forward-forward configuration. Octave and one-third octave band spectra taken during a variety of locomotive operating conditions are presented. The octave band centered at 31.5 Hz contains nearly 46% of the acoustical energy, and those centered at and below 250 Hz contain nearly 99% of the acoustical energy. Wheel-rail interaction appears to be the predominant source of the low frequency noise. Recommendations for controlling exposure are made. PMID:14521423

  10. Biomedical perspectives on locomotion in null gravity

    NASA Technical Reports Server (NTRS)

    Cavanagh, Peter R.

    1989-01-01

    A number of important features of various locomotor activities are discussed, and approaches to the study of these activities in the context of space flight are suggested. In particular, the magnitude of peak forces and the rates of change of force during terrestrial cycling, walking, and running are compared. It is shown that subtle changes in the conditions and techniques of locomotion can have a major influence on the biomechanical consequences to the skeleton. The various hypotheses that identify locomotor exercise as a countermeasure to bone demineralization during weightlessness deserve to be tested with some degree of biomechanical rigor. Various approaches for achieving such scrutiny are discussed.

  11. Hamiltonian mechanics and planar fishlike locomotion

    NASA Astrophysics Data System (ADS)

    Kelly, Scott; Xiong, Hailong; Burgoyne, Will

    2007-11-01

    A free deformable body interacting with a system of point vortices in the plane constitutes a Hamiltonian system. A free Joukowski foil with variable camber shedding point vortices in an ideal fluid according to a periodically applied Kutta condition provides a model for fishlike locomotion which bridges the gap between inviscid analytical models that sacrifice realism for tractability and viscous computational models inaccessible to tools from nonlinear control theory. We frame such a model in the context of Hamiltonian mechanics and describe its relevance both to the study of hydrodynamic interactions within schools of fish and to the realization of model-based control laws for biomimetic autonomous robotic vehicles.

  12. Why arboreal snakes should not be cylindrical: body shape, incline and surface roughness have interactive effects on locomotion.

    PubMed

    Jayne, Bruce C; Newman, Steven J; Zentkovich, Michele M; Berns, H Matthew

    2015-12-01

    Depending on animal size, shape, body plan and behaviour, variation in surface structure can affect the speed and ease of locomotion. The slope of branches and the roughness of bark both vary considerably, but their combined effects on the locomotion of arboreal animals are poorly understood. We used artificial branches with five inclines and five peg heights (≤40 mm) to test for interactive effects on the locomotion of three snake species with different body shapes. Unlike boa constrictors (Boa constrictor), corn snakes (Pantherophis guttatus) and brown tree snakes (Boiga irregularis) can both form ventrolateral keels, which are most pronounced in B. irregularis. Increasing peg height up to 10 mm elicited more of the lateral undulatory behaviour (sliding contact without gripping) rather than the concertina behaviour (periodic static gripping) and increased the speed of lateral undulation. Increased incline: (1) elicited more concertina locomotion, (2) decreased speed and (3) increased the threshold peg height that elicited lateral undulation. Boiga irregularis was the fastest species, and it used lateral undulation on the most surfaces, including a vertical cylinder with pegs only 1 mm high. Overall, B. constrictor was the slowest and used the most concertina locomotion, but this species climbed steep, smooth surfaces faster than P. guttatus. Our results illustrate how morphology and two different aspects of habitat structure can have interactive effects on organismal performance and behaviour. Notably, a sharper keel facilitated exploiting shorter protrusions to prevent slipping and provide propulsion, which became increasingly important as surface steepness increased. PMID:26677261

  13. Locomotion Induced by Spatial Restriction in Adult Drosophila

    PubMed Central

    Xiao, Chengfeng; Robertson, R. Meldrum

    2015-01-01

    Drosophila adults display an unwillingness to enter confined spaces but the behaviors induced by spatial restriction in Drosophila are largely unknown. We developed a protocol for high-throughput analysis of locomotion and characterized features of locomotion in a restricted space. We observed intense and persistent locomotion of flies in small circular arenas (diameter 1.27 cm), whereas locomotion was greatly reduced in large circular arenas (diameter 3.81 cm). The increased locomotion induced by spatial restriction was seen in male flies but not female flies, indicating sexual dimorphism of the response to spatial restriction. In large arenas, male flies increased locomotion in arenas previously occupied by male but not female individuals. In small arenas, such pre-conditioning had no effect on male flies, which showed intense and persistent locomotion similar to that seen in fresh arenas. During locomotion with spatial restriction, wildtype Canton-S males traveled slower and with less variation in speed than the mutant w1118 carrying a null allele of white gene. In addition, wildtype flies showed a stronger preference for the boundary than the mutant in small arenas. Genetic analysis with a series of crosses revealed that the white gene was not associated with the phenotype of boundary preference in wildtype flies. PMID:26351842

  14. Looking north toward Locomotive Shop (2 tracks on left), Car ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking north toward Locomotive Shop (2 tracks on left), Car Shop on right, and flat car in foreground. Note locomotive and car tires leaning on stock shed at left - East Broad Top Railroad & Coal Company, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

  15. Economic assessment of coal-burning locomotives: Topical report

    SciTech Connect

    Not Available

    1986-02-01

    The General Electric Company embarked upon a study to evaluate various alternatives for the design and manufacture a coal fired locomotive considering various prime movers, but retaining the electric drive transmission. The initial study was supported by the Burlington-Northern and Norfolk-Southern railroads, and included the following alternatives: coal fired diesel locomotive; direct fired gas turbine locomotives; direct fired gas turbine locomotive with steam injection; raw coal gasifier gas turbine locomotive; and raw coal fluid bed steam turbine locomotive. All alternatives use the electric drive transmission and were selected for final evaluation. The first three would use a coal water slurry as a fuel, which must be produced by new processing plants. Therefore, use of a slurry would require a significant plant capital investment. The last two would use classified run-of-the-mine (ROM) coal with much less capital expenditure. Coal fueling stations would be required but are significantly lower in capital cost than a coal slurry plant. For any coal fired locomotive to be commercially viable, it must pass the following criteria: be technically feasible and environmentally acceptable; meet railroads' financial expectations; and offer an attractive return to the locomotive manufacturer. These three criteria are reviewed in the report.

  16. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... families. 1033.230 Section 1033.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Certifying Engine Families § 1033.230 Grouping locomotives into engine families. (a) Divide your product line into engine families of...

  17. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... families. 1033.230 Section 1033.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Certifying Engine Families § 1033.230 Grouping locomotives into engine families. (a) Divide your product line into engine families of...

  18. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... families. 1033.230 Section 1033.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Certifying Engine Families § 1033.230 Grouping locomotives into engine families. (a) Divide your product line into engine families of...

  19. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... families. 1033.230 Section 1033.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Certifying Engine Families § 1033.230 Grouping locomotives into engine families. (a) Divide your product line into engine families of...

  20. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... reservoir on locomotives and related piping shall be zero, unless the system is capable of maintaining the... equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the system logs or displays a fault related to equalizing reservoir leakage, the train may be moved only to...

  1. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  2. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  3. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  4. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  5. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  6. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRAKE SYSTEM SAFETY STANDARDS FOR FREIGHT AND OTHER NON-PASSENGER... reservoir on locomotives and related piping shall be zero, unless the system is capable of maintaining the... equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  7. 49 CFR 236.509 - Two or more locomotives coupled.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Two or more locomotives coupled. 236.509 Section... Train Stop, Train Control and Cab Signal Systems Standards § 236.509 Two or more locomotives coupled. The automatic train stop, train control or cab signal apparatus shall be arranged so that when two...

  8. 40 CFR 92.104 - Locomotive and engine testing; overview.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... restriction within 1 inch of water of the upper limit of a typical engine as installed with clean air filters... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Locomotive and engine testing....104 Locomotive and engine testing; overview. (a) The test procedures described here...

  9. 40 CFR 92.104 - Locomotive and engine testing; overview.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... restriction within 1 inch of water of the upper limit of a typical engine as installed with clean air filters... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Locomotive and engine testing....104 Locomotive and engine testing; overview. (a) The test procedures described here...

  10. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  11. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  12. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  13. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  14. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  15. 77 FR 30047 - Petition for Alternative Locomotive Crashworthiness Design

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Federal Railroad Administration Petition for Alternative Locomotive Crashworthiness Design In accordance... design for an electric locomotive, Model ACS-64, built by Siemens Industry, Inc. This request is made in...-0036. The alternative design incorporates crash energy management features, detailed in the...

  16. 49 CFR 229.13 - Control of locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... coupled in remote or multiple control, the propulsion system, the sanders, and the power brake system of each locomotive shall respond to control from the cab of the controlling locomotive. If a dynamic brake or regenerative brake system is in use, that portion of the system in use shall respond to...

  17. Job Grading Standard for Locomotive Engineer WG-6004.

    ERIC Educational Resources Information Center

    Civil Service Commission, Washington, DC. Bureau of Policies and Standards.

    The standard is used to grade the nonsupervisory work of operating all types of locomotives and trains to transport supplies, equipment, conveyances, and personnel. The work involves skill in operating locomotives under various conditions, and knowledge of the layout of a track system and the safety, signalling, and track use requirements or…

  18. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... classification of cars according to commodity or destination; assembling of cars for train movements; changing... constitute a road movement. However, this term does not include movement of a train or part of a train within yard limits by the road locomotive and the placement of locomotives or cars in a train or their...

  19. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... classification of cars according to commodity or destination; assembling of cars for train movements; changing... constitute a road movement. However, this term does not include movement of a train or part of a train within yard limits by the road locomotive and the placement of locomotives or cars in a train or their...

  20. Proprioceptive Actuation Design for Dynamic Legged locomotion

    NASA Astrophysics Data System (ADS)

    Kim, Sangbae; Wensing, Patrick; Biomimetic Robotics Lab Team

    Designing an actuator system for highly-dynamic legged locomotion exhibited by animals has been one of the grand challenges in robotics research. Conventional actuators designed for manufacturing applications have difficulty satisfying challenging requirements for high-speed locomotion, such as the need for high torque density and the ability to manage dynamic physical interactions. It is critical to introduce a new actuator design paradigm and provide guidelines for its incorporation in future mobile robots for research and industry. To this end, we suggest a paradigm called proprioceptive actuation, which enables highly- dynamic operation in legged machines. Proprioceptive actuation uses collocated force control at the joints to effectively control contact interactions at the feet under dynamic conditions. In the realm of legged machines, this paradigm provides a unique combination of high torque density, high-bandwidth force control, and the ability to mitigate impacts through backdrivability. Results show that the proposed design provides an impact mitigation factor that is comparable to other quadruped designs with series springs to handle impact. The paradigm is shown to enable the MIT Cheetah to manage the application of contact forces during dynamic bounding, with results given down to contact times of 85ms and peak forces over 450N. As a result, the MIT Cheetah achieves high-speed 3D running up to 13mph and jumping over an 18-inch high obstacle. The project is sponsored by DARPA M3 program.

  1. Environmental engineering simplifies subterranean locomotion control

    NASA Astrophysics Data System (ADS)

    Gravish, Nick; Monaenkova, Darya; Goodisman, Michael A. D.; Goldman, Daniel I.

    2013-03-01

    We hypothesize that ants engineer habitats which reduce locomotion control requirements. We studied tunnel construction, and locomotion, in fire ants (Solenopsis invicta, body length L = 0 . 35 +/- 0 . 05). In their daily life, ants forage for food above ground and return resources to the nest. This steady-state tunnel traffic enables high-throughput biomechanics studies of tunnel climbing. In a laboratory experiment we challenged fire ants to climb through 8 cm long glass tunnels (D = 0.1 - 0.9 cm) that separated a nest from an open arena with food and water. During ascending and descending climbs we induced falls by a motion-activated rapid, short, downward translation of the tunnels. Normalized tunnel diameter (D / L) determined the ability of ants to rapidly recover from perturbations. Fall arrest probability was unity for small D / L , and zero for large D / L . The transition from successful to unsuccessful arrest occurred at D / L = 1 . 4 +/- 0 . 3 . Through X-Ray computed tomography study we show that the diameter of ant-excavated tunnels is independent of soil-moisture content (studied from 1-20%) and particle size (50-595 μm diameter), and has a mean value of D / L = 1 . 06 +/- 0 . 23 . Thus fire ants construct tunnels of diameter near the onset of fall instability.

  2. Turning and maneuverability during sidewinding locomotion

    NASA Astrophysics Data System (ADS)

    Astley, Henry; Goldman, Daniel; Hu, David

    2014-03-01

    Sidewinding is an unusual form of snake locomotion used to move rapidly on yielding substrates such as desert sands. Posteriorly propagating waves alternate between static contact with the substrate and elevated motion, resulting in a ``stepping'' motion of body segments. Unlike lateral undulation, the direction of travel is not collinear with the axis of the body wave, and posterior body segments do not follow the path of anterior segments. Field observations indicate that sidewinding snakes are highly maneuverable, but the mechanisms by which these snakes change direction during this complex movement are unknown. Motion capture data from three Colorado Desert sidewinder rattlesnakes (Crotalus cerastes laterorepens) shows a variety of turn magnitudes and behaviors. Additionally, sidewinders are capable of ``reversals'' in which the snakes halts forward progress and begins locomotion in the opposite direction without rotation of the body. Because the head is re-oriented with respect to the body during these reversals, the snake is able to reverse direction without rotation yet continue moving in the new direction without impediment to perception or mechanics, a rare level of maneuverability in animals.

  3. Locomotion of a flapping flexible plate

    NASA Astrophysics Data System (ADS)

    Hua, Ru-Nan; Zhu, Luoding; Lu, Xi-Yun

    2013-12-01

    The locomotion of a flapping flexible plate in a viscous incompressible stationary fluid is numerically studied by an immersed boundary-lattice Boltzmann method for the fluid and a finite element method for the plate. When the leading-edge of the flexible plate is forced to heave sinusoidally, the entire plate starts to move freely as a result of the fluid-structure interaction. Mechanisms underlying the dynamics of the plate are elucidated. Three distinct states of the plate motion are identified and can be described as forward, backward, and irregular. Which state to occur depends mainly on the heaving amplitude and the bending rigidity of the plate. In the forward motion regime, analysis of the dynamic behaviors of the flapping flexible plate indicates that a suitable degree of flexibility can improve the propulsive performance. Moreover, there exist two kinds of vortex streets in the downstream of the plate which are normal and deflected wake. Further the forward motion is compared with the flapping-based locomotion of swimming and flying animals. The results obtained in the present study are found to be consistent with the relevant observations and measurements and can provide some physical insights into the understanding of the propulsive mechanisms of swimming and flying animals.

  4. Bipedal and quadrupedal locomotion in chimpanzees.

    PubMed

    Pontzer, Herman; Raichlen, David A; Rodman, Peter S

    2014-01-01

    Chimpanzees (Pan troglodytes) habitually walk both bipedally and quadrupedally, and have been a common point of reference for understanding the evolution of bipedal locomotion in early ape-like hominins. Here we compare the kinematics, kinetics, and energetics of bipedal and quadrupedal walking and running in a sample of five captive chimpanzees. Kinematics were recorded using sagittal-plane digital high-speed video of treadmill trials. Kinetics were recorded via a forceplate. Metabolic energy cost was measured via steady-state oxygen consumption during treadmill trials. Consistent with previous work on chimpanzees and other hominoids, we found that the spatiotemporal characteristics, joint angles, ground reaction forces, and metabolic cost of bipedal and quadrupedal locomotion are similar in chimpanzees. Notable differences include hip and trunk angles, which reflected a more orthograde trunk posture during bipedalism, and mediolateral ground reaction forces, which were larger during bipedal walking. Stride frequencies were also higher (and step lengths shorter) during bipedal trials. Bipedal and quadrupedal walking among chimpanzees was similar to that reported for bonobos, gibbons, and other primates. The similarity in cost between bipedal and quadrupedal trials suggests that the adoption of bipedal walking would have had no effect on walking costs for early ape-like hominins. However, habitual bipedalism may have favored modifications of the hip to allow a more orthograde posture, and of the hind limb abductor mechanisms to efficiently exert mediolateral ground forces. PMID:24315239

  5. A Review of Locomotion Systems for Capsule Endoscopy.

    PubMed

    Liu, Lejie; Towfighian, Shahrzad; Hila, Amine

    2015-01-01

    Wireless capsule endoscopy for gastrointestinal (GI) tract is a modern technology that has the potential to replace conventional endoscopy techniques. Capsule endoscopy is a pill-shaped device embedded with a camera, a coin battery, and a data transfer. Without a locomotion system, this capsule endoscopy can only passively travel inside the GI tract via natural peristalsis, thus causing several disadvantages such as inability to control and stop, and risk of capsule retention. Therefore, a locomotion system needs to be added to optimize the current capsule endoscopy. This review summarizes the state-of-the-art locomotion methods along with the desired locomotion features such as size, speed, power, and temperature and compares the properties of different methods. In addition, properties and motility mechanisms of the GI tract are described. The main purpose of this review is to understand the features of GI tract and diverse locomotion methods in order to create a future capsule endoscopy compatible with GI tract properties. PMID:26292162

  6. Sensory feedback in cockroach locomotion: current knowledge and open questions.

    PubMed

    Ayali, A; Couzin-Fuchs, E; David, I; Gal, O; Holmes, P; Knebel, D

    2015-09-01

    The American cockroach, Periplaneta americana, provides a successful model for the study of legged locomotion. Sensory regulation and the relative importance of sensory feedback vs. central control in animal locomotion are key aspects in our understanding of locomotive behavior. Here we introduce the cockroach model and describe the basic characteristics of the neural generation and control of walking and running in this insect. We further provide a brief overview of some recent studies, including mathematical modeling, which have contributed to our knowledge of sensory control in cockroach locomotion. We focus on two sensory mechanisms and sense organs, those providing information related to loading and unloading of the body and the legs, and leg-movement-related sensory receptors, and present evidence for the instrumental role of these sensory signals in inter-leg locomotion control. We conclude by identifying important open questions and indicate future perspectives. PMID:25432627

  7. Spontaneous perseverative turning in rats with radiation-induced hippocampal damage

    SciTech Connect

    Mickley, G.A.; Ferguson, J.L.; Nemeth, T.J.; Mulvihill, M.A.; Alderks, C.E. )

    1989-08-01

    This study found a new behavioral correlate of lesions specific to the dentate granule cell layer of the hippocampus: spontaneous perseverative turning. Irradiation of a portion of the neonatal rat cerebral hemispheres produced hypoplasia of the granule cell layer of the hippocampal dentate gyrus while sparing the rest of the brain. Radiation-induced damage to the hippocampal formation caused rats placed in bowls to spontaneously turn in long, slow bouts without reversals. Irradiated subjects also exhibited other behaviors characteristic of hippocampal damage (e.g., perseveration in spontaneous exploration of the arms of a T-maze, retarded acquisition of a passive avoidance task, and increased horizontal locomotion). These data extend previously reported behavioral correlates of fascia dentata lesions and suggest the usefulness of a bout analysis of spontaneous bowl turning as a measure of nondiscrete-trial spontaneous alternation and a sensitive additional indicator of radiation-induced hippocampal damage.

  8. Women's perceptions of first trimester spontaneous abortion.

    PubMed

    Wall-Haas, C L

    1985-01-01

    Fifteen to twenty percent of all pregnancies end in spontaneous abortion. For many women, this loss is nearly the equivalent of the loss of a real baby. To explore the complexity of women's responses to spontaneous abortion, nine women were given a questionnaire to complete regarding experiences and behaviors at the time of the miscarriage. The data revealed that each woman was affected, to some degree, by her experience with a spontaneous abortion. A comprehensive psychologic approach to this special client is needed to help more effectively the woman who aborts in the first trimester cope with the very real loss of an infant. PMID:3844461

  9. Ground Reaction Forces During Locomotion in Simulated Microgravity

    NASA Technical Reports Server (NTRS)

    Davis, B. L.; Cavanagh, Peter R.; Sommer, H. J., III; Wu, G.

    1996-01-01

    Significant losses in bone density and mineral, primarily in the lower extremities have been reported following exposure to weightlessness. Recent investigations suggest that mechanical influences such as bone deformation and strain rate may be critically important in stimulating new bone formation. It was hypothesized that velocity, cadence and harness design would significantly affect lower limb impact forces during treadmill exercise in simulated zero gravity (0G). A ground-based hypogravity simulator was used to investigate which factors affect limb loading during tethered treadmill exercise. A fractional factorial design was used and 12 subjects were studied. The results showed that running on active and passive treadmills in the simulator with a tethering force close to the maximum comfortable level produced similar magnitudes for the peak ground reaction force. It was also found that these maximum forces were significantly lower than those obtained during overground trials, even when the speeds of locomotion in the simulator were 66 % greater than those in 1 G. Cadence had no effect on any of the response variables. The maximum rate of force application (DFDT-Max) was similar for overground running and exercise in simulated 0G, provided that the "weightless subjects ran on a motorized treadmill. These findings have implications for the use of treadmill exercise as a countermeasure for hypokinetic osteoporosis. As the relationship between mechanical factors and osteogenesis becomes better understood, results from human experiments in 0G simulators will help to design in-flight exercise programs that are more closely targeted to generate appropriate mechanical stimuli.

  10. Cerebellar contribution to feedforward control of locomotion

    PubMed Central

    Pisotta, Iolanda; Molinari, Marco

    2014-01-01

    The cerebellum is an important contributor to feedforward control mechanisms of the central nervous system, and sequencing—the process that allows spatial and temporal relationships between events to be recognized—has been implicated as the fundamental cerebellar mode of operation. By adopting such a mode and because cerebellar activity patterns are sensitive to a variety of sensorimotor-related tasks, the cerebellum is believed to support motor and cognitive functions that are encoded in the frontal and parietal lobes of the cerebral cortex. In this model, the cerebellum is hypothesized to make predictions about the consequences of a motor or cognitive command that originates from the cortex to prepare the entire system to cope with ongoing changes. In this framework, cerebellar predictive mechanisms for locomotion are addressed, focusing on sensorial and motoric sequencing. The hypothesis that sequence recognition is the mechanism by which the cerebellum functions in gait control is presented and discussed. PMID:25009490

  11. Cocaine modulates locomotion behavior in C. elegans.

    PubMed

    Ward, Alex; Walker, Vyvyca J; Feng, Zhaoyang; Xu, X Z Shawn

    2009-01-01

    Cocaine, a potent addictive substance, is an inhibitor of monoamine transporters, including DAT (dopamine transporter), SERT (serotonin transporter) and NET (norepinephrine transporter). Cocaine administration induces complex behavioral alterations in mammals, but the underlying mechanisms are not well understood. Here, we tested the effect of cocaine on C. elegans behavior. We show for the first time that acute cocaine treatment evokes changes in C. elegans locomotor activity. Interestingly, the neurotransmitter serotonin, rather than dopamine, is required for cocaine response in C. elegans. The C. elegans SERT MOD-5 is essential for the effect of cocaine, consistent with the role of cocaine in targeting monoamine transporters. We further show that the behavioral response to cocaine is primarily mediated by the ionotropic serotonin receptor MOD-1. Thus, cocaine modulates locomotion behavior in C. elegans primarily by impinging on its serotoninergic system. PMID:19536276

  12. Locomotion of C elegans in structured environments

    NASA Astrophysics Data System (ADS)

    Majmudar, Trushant; Keaveny, Eric; Shelley, Michael; Zhang, Jun

    2011-11-01

    We have established a combined experimental and numerical platform to study the swimming dynamics of an undulating worm in structured environments (fluid-filled micro-pillar arrays). We have shown that the worm (C. elegans) swims with different velocity and frequency depending on the lattice spacing and our purely mechanistic simulations (elastically linked bead-chain) reproduce the experimental results qualitatively and quantitatively, including ``life-like'' trajectories the worm exhibits. We build upon this platform to investigate more complex environments, such as linear and radial lattices, with gradients in spacing. In addition, we study C. elegans mutants to investigate the role of length of the worm, frequency of undulations, and mechano-sensation on the resultant dynamics. We also examine the worm moving through a lattice with random distribution of obstacles - a model soil-like environment. Our combined experimental and simulations approach allows us to gain insights into the dynamics of locomotion of undulating microorganisms in realistic complex environments.

  13. Locomotion by Tandem and Parallel Wings

    NASA Astrophysics Data System (ADS)

    Tanida, Yoshimichi

    A two-dimensional analysis was carried out on the locomotion by tandem and parallel wings in relation to the free flight of dragonflies and beetles, remarking the mutual interference between fore and hind wings. The results obtained are summarized as follows: In the case of tandem wings, (1)High thrust and propulsive efficiency can be achieved when the forewing oscillates with a definite phase lag behind the hindwing, as in the case of real dragonflies, (2)Somewhat smaller amplitude of hindwing leads to optimum condition for work sharing of two wings, (3)The hard forewing does not serve for the thrust and propulsive efficiency, whereas the hard hindwing does for the augmentation of them; In the case of parallel wings, (4)The hard wing placed near the soft wing acts nearly as an infinite plate, as for the ground effect, increasing both thrust and propulsive efficiency.

  14. Hydrodynamics and control of microbial locomotion

    NASA Astrophysics Data System (ADS)

    Dunkel, Jorn; Kantsler, Vasily; Polin, Marco; Wioland, Hugo; Goldstein, Raymond

    2014-03-01

    Interactions between swimming cells, surfaces and fluid flow are essential to many microbiological processes, from the formation of biofilms to the fertilization of human egg cells. Yet, relatively little remains known quantitatively about the physical mechanisms that govern the response of bacteria, algae and sperm cells to flow velocity gradients and solid surfaces. A better understanding of cell-surface and cell-flow interactions promises new biological insights and may advance microfluidic techniques for controlling microbial and sperm locomotion, with potential applications in diagnostics and therapeutic protein synthesis. Here, we report new experimental measurements that quantify surface interactions of bacteria, unicellular green algae and mammalian spermatozoa. These experiments show that the subtle interplay of hydrodynamics and surface interactions can stabilize collective bacterial motion, that direct ciliary contact interactions dominate surface scattering of eukaryotic biflagellate algae, and that rheotaxis combined with steric surface interactions provides a robust long-range navigation mechanism for sperm cells.

  15. Undulatory Locomotion of Magnetic Multilink Nanoswimmers.

    PubMed

    Jang, Bumjin; Gutman, Emiliya; Stucki, Nicolai; Seitz, Benedikt F; Wendel-García, Pedro D; Newton, Taylor; Pokki, Juho; Ergeneman, Olgaç; Pané, Salvador; Or, Yizhar; Nelson, Bradley J

    2015-07-01

    Micro- and nanorobots operating in low Reynolds number fluid environments require specialized swimming strategies for efficient locomotion. Prior research has focused on designs mimicking the rotary corkscrew motion of bacterial flagella or the planar beating motion of eukaryotic flagella. These biologically inspired designs are typically of uniform construction along their flagellar axis. This work demonstrates for the first time planar undulations of composite multilink nanowire-based chains (diameter 200 nm) induced by a planar-oscillating magnetic field. Those chains comprise an elastic eukaryote-like polypyrrole tail and rigid magnetic nickel links connected by flexible polymer bilayer hinges. The multilink design exhibits a high swimming efficiency. Furthermore, the manufacturing process enables tuning the geometrical and material properties to specific applications. PMID:26029795

  16. Cerebellar contribution to feedforward control of locomotion.

    PubMed

    Pisotta, Iolanda; Molinari, Marco

    2014-01-01

    The cerebellum is an important contributor to feedforward control mechanisms of the central nervous system, and sequencing-the process that allows spatial and temporal relationships between events to be recognized-has been implicated as the fundamental cerebellar mode of operation. By adopting such a mode and because cerebellar activity patterns are sensitive to a variety of sensorimotor-related tasks, the cerebellum is believed to support motor and cognitive functions that are encoded in the frontal and parietal lobes of the cerebral cortex. In this model, the cerebellum is hypothesized to make predictions about the consequences of a motor or cognitive command that originates from the cortex to prepare the entire system to cope with ongoing changes. In this framework, cerebellar predictive mechanisms for locomotion are addressed, focusing on sensorial and motoric sequencing. The hypothesis that sequence recognition is the mechanism by which the cerebellum functions in gait control is presented and discussed. PMID:25009490

  17. Fish locomotion: recent advances and new directions.

    PubMed

    Lauder, George V

    2015-01-01

    Research on fish locomotion has expanded greatly in recent years as new approaches have been brought to bear on a classical field of study. Detailed analyses of patterns of body and fin motion and the effects of these movements on water flow patterns have helped scientists understand the causes and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swimming fish in the oceans and the vorticity present in fin and body wakes support the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail. PMID:25251278

  18. Fish Locomotion: Recent Advances and New Directions

    NASA Astrophysics Data System (ADS)

    Lauder, George V.

    2015-01-01

    Research on fish locomotion has expanded greatly in recent years as new approaches have been brought to bear on a classical field of study. Detailed analyses of patterns of body and fin motion and the effects of these movements on water flow patterns have helped scientists understand the causes and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swimming fish in the oceans and the vorticity present in fin and body wakes support the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail.

  19. Biofluiddynamics of balistiform and gymnotiform locomotion: Revisited

    NASA Astrophysics Data System (ADS)

    Sprinkle, Brennan; Bale, Rahul; Singh, Amneet; Chen, Nelson; Maciver, Malcom; Patankar, Neelesh

    2015-11-01

    Gymnotiform and balistiform swimmers are those which have an undulatory fin affixed to a rigid body unlike anguilliforms who undulate their entire body. Is there a mechanical advantage to gymnotiform and balistiform swimming? This question was investigated by Lighthill & Blake in a four paper series Biofluiddynamics of balistiform and gymnotiform locomotion. We revisit this work using fully resolved numerical simulations of the types of swimmers considered by Lighthill & Blake to interrogate the issue of mechanical advantage for rigid body swimmers. In doing so, we find that while there is advantage to rigid body swimming, the mechanism of `momentum enhancement,' proposed by Lighthill and Blake, is not the cause. Further, we use our results and simulations to explain why some gymnotiform and balistiform swimmers have their propulsor attached to their bodies at an angle. This work was supported in part by NSF grants CBET-0828749, CMMI-0941674 and CBET-1066575. Computational resources were provided by Northwestern University High Performance Computing System-Quest.

  20. Dynamic legged locomotion in robots and animals

    NASA Astrophysics Data System (ADS)

    Raibert, Marc; Playter, Robert; Ringrose, Robert; Bailey, Dave; Leeser, Karl

    1995-01-01

    This report documents our study of active legged systems that balance actively and move dynamically. The purpose of this research is to build a foundation of knowledge that can lead both to the construction of useful legged vehicles and to a better understanding of how animal locomotion works. In this report we provide an update on progress during the past year. Here are the topics covered in this report: (1) Is cockroach locomotion dynamic? To address this question we created three models of cockroaches, each abstracted at a different level. We provided each model with a control system and computer simulation. One set of results suggests that 'Groucho Running,' a type of dynamic walking, seems feasible at cockroach scale. (2) How do bipeds shift weight between the legs? We built a simple planar biped robot specifically to explore this question. It shifts its weight from one curved foot to the other, using a toe-off and toe-on strategy, in conjunction with dynamic tipping. (3) 3D biped gymnastics: The 3D biped robot has done front somersaults in the laboratory. The robot changes its leg length in flight to control rotation rate. This in turn provides a mechanism for controlling the landing attitude of the robot once airborne. (4) Passively stabilized layout somersault: We have found that the passive structure of a gymnast, the configuration of masses and compliances, can stabilize inherently unstable maneuvers. This means that body biomechanics could play a larger role in controlling behavior than is generally thought. We used a physical 'doll' model and computer simulation to illustrate the point. (5) Twisting: Some gymnastic maneuvers require twisting. We are studying how to couple the biomechanics of the system to its control to produce efficient, stable twisting maneuvers.

  1. Speeding up spontaneous disease extinction

    NASA Astrophysics Data System (ADS)

    Khasin, Michael

    2012-02-01

    The dynamics of epidemic in a susceptible population is affected both by the random character of interactions between the individuals and by environmental variations. As a consequence, the sizes of the population groups (infected, susceptible, etc.) fluctuate in the course of evolution of the epidemic. In a small community a rare large fluctuation in the number of infected can result in extinction of the disease. We suggest a novel paradigm of controlling the epidemic, where the control field, such as vaccination, is designed to maximize the rate of spontaneous disease extinction. We show that, for a limited-scope vaccination, the optimal vaccination protocol and its impact on the epidemics have universal features: (i) the vaccine must be applied in pulses, (ii) the spontaneous disease extinction is synchronized with the vaccination. We trace this universality to general properties of the response of large fluctuations to external perturbations.

  2. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  3. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  4. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  5. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  6. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  7. Recovery of locomotion after spinal cord injury: some facts and mechanisms.

    PubMed

    Rossignol, Serge; Frigon, Alain

    2011-01-01

    After spinal cord injury (SCI), various sensorimotor functions can recover, ranging from simple spinal reflexes to more elaborate motor patterns, such as locomotion. Locomotor recovery after complete spinalization (complete SCI) must depend on the presence of spinal circuitry capable of generating the complex sequential activation of various leg muscles. This is achieved by an intrinsic spinal circuitry, termed the central pattern generator (CPG), working in conjunction with sensory feedback from the legs. After SCI, different changes in cellular and circuit properties occur spontaneously and can be promoted by pharmacological, electrical, or rehabilitation strategies. After partial SCI, hindlimb locomotor recovery can result from regeneration or sprouting of spared pathways, but also from mechanisms observed after complete SCI, namely changes within the intrinsic spinal circuitry and sensory inputs. PMID:21469957

  8. Shape-switching microrobots for medical applications: the influence of shape in drug delivery and locomotion.

    PubMed

    Fusco, Stefano; Huang, Hen-Wei; Peyer, Kathrin E; Peters, Christian; Häberli, Moritz; Ulbers, André; Spyrogianni, Anastasia; Pellicer, Eva; Sort, Jordi; Pratsinis, Sotiris E; Nelson, Bradley J; Sakar, Mahmut Selman; Pané, Salvador

    2015-04-01

    The effect of dynamic shape switching of hydrogel bilayers on the performance of self-folding microrobots is investigated for navigation in body orifices and drug release on demand. Tubular microrobots are fabricated by coupling a thermoresponsive hydrogel nanocomposite with a poly(ethylene glycol)diacrylate (PEGDA) layer, to achieve spontaneous and reversible folding from a planar rectangular structure. Graphene oxide (GO) or silica-coated superparamagnetic iron oxide nanoparticles are dispersed in the thermoresponsive hydrogel matrix to provide near-infrared (NIR) light sensitivity or magnetic actuation, respectively. The NIR light-responsive microstructures are fabricated for triggered drug delivery while magnetic nanocomposite-based microrobots are used to analyze the role of shape in locomotion. Experimental analysis and computational simulations of tubular structures show that drug release and motility can be optimized through controlled shape change. These concepts are finally applied to helical microrobots to show a possible way to achieve autonomous behavior. PMID:25751020

  9. How to find home backwards? Locomotion and inter-leg coordination during rearward walking of Cataglyphis fortis desert ants.

    PubMed

    Pfeffer, Sarah E; Wahl, Verena L; Wittlinger, Matthias

    2016-07-15

    For insects, flexibility in the performance of terrestrial locomotion is a vital part of facing the challenges of their often unpredictable environment. Arthropods such as scorpions and crustaceans can switch readily from forward to backward locomotion, but in insects this behaviour seems to be less common and, therefore, is only poorly understood. Here we present an example of spontaneous and persistent backward walking in Cataglyphis desert ants that allows us to investigate rearward locomotion within a natural context. When ants find a food item that is too large to be lifted up and to be carried in a normal forward-faced orientation, they will drag the load walking backwards to their home nest. A detailed examination of this behaviour reveals a surprising flexibility of the locomotor output. Compared with forward walks with regular tripod coordination, no main coordination pattern can be assigned to rearward walks. However, we often observed leg-pair-specific stepping patterns. The front legs frequently step with small stride lengths, while the middle and the hind legs are characterized by less numerous but larger strides. But still, these specializations show no rigidly fixed leg coupling, nor are they strictly embedded within a temporal context; therefore, they do not result in a repetitive coordination pattern. The individual legs act as separate units, most likely to better maintain stability during backward dragging. PMID:27445398

  10. Locomotion of bacteria in liquid flow and the boundary layer effect on bacterial attachment

    SciTech Connect

    Zhang, Chao; Liao, Qiang; Chen, Rong; Zhu, Xun

    2015-06-12

    The formation of biofilm greatly affects the performance of biological reactors, which highly depends on bacterial swimming and attachment that usually takes place in liquid flow. Therefore, bacterial swimming and attachment on flat and circular surfaces with the consideration of flow was studied experimentally. Besides, a mathematical model comprehensively combining bacterial swimming and motion with flow is proposed for the simulation of bacterial locomotion and attachment in flow. Both experimental and theoretical results revealed that attached bacteria density increases with decreasing boundary layer thickness on both flat and circular surfaces, the consequence of which is inherently related to the competition between bacterial swimming and the non-slip motion with flow evaluated by the Péclet number. In the boundary layer, where the Péclet number is relatively higher, bacterial locomotion mainly depends on bacterial swimming. Thinner boundary layer promotes bacterial swimming towards the surface, leading to higher attachment density. To enhance the performance of biofilm reactors, it is effective to reduce the boundary layer thickness on desired surfaces. - Highlights: • Study of bacterial locomotion in flow as an early stage in biofilm formation. • Mathematical model combining bacterial swimming and the motion with flow. • Boundary layer plays a key role in bacterial attachment under flow condition. • The competition between bacterial swimming and the motion with flow is evaluated.

  11. Quantitative analysis of hindlimbs locomotion kinematics in spinalized rats treated with Tamoxifen plus treadmill exercise.

    PubMed

    Osuna-Carrasco, L P; López-Ruiz, J R; Mendizabal-Ruiz, E G; De la Torre-Valdovinos, B; Bañuelos-Pineda, J; Jiménez-Estrada, I; Dueñas-Jiménez, S H

    2016-10-01

    Locomotion recovery after a spinal cord injury (SCI) includes axon regeneration, myelin preservation and increased plasticity in propriospinal and descending spinal circuitries. The combined effects of tamoxifen and exercise after a SCI were analyzed in this study to determine whether the combination of both treatments induces the best outcome in locomotion recovery. In this study, the penetrating injury was provoked by a sharp projectile that penetrates through right dorsal and ventral portions of the T13-L1 spinal segments, affecting propriospinal and descending/ascending tracts. Intraperitoneal application of Tamoxifen and a treadmill exercise protocol, as rehabilitation therapies, separately or combined, were used. To evaluate the functional recovery, angular patterns of the hip, knee and ankle joints as well as the leg pendulum-like movement (PLM) were measured during the unrestricted gait of treated and untreated (UT) animals, previously and after the traumatic injury (15 and 30days post-injury (dpi)). A pattern (curve) comparison analysis was made by using a locally designed Matlab script that determines the Frechet dissimilarity. The SCI magnitude was assessed by qualitative and quantitative histological analysis of the injury site 30days after SCI. Our results showed that all treated groups had an improvement in hindlimbs kinematics compared to the UT group, which showed a poor gait locomotion recovery throughout the rehabilitation period. The group with the combined treatment (tamoxifen+exercise (TE)) presented the best outcome. In conclusion, tamoxifen and treadmill exercise treatments are complementary therapies for the functional recovery of gait locomotion in hemi-spinalized rats. PMID:27450566

  12. Synaptic representation of locomotion in single cerebellar granule cells

    PubMed Central

    Powell, Kate; Mathy, Alexandre; Duguid, Ian; Häusser, Michael

    2015-01-01

    The cerebellum plays a crucial role in the regulation of locomotion, but how movement is represented at the synaptic level is not known. Here, we use in vivo patch-clamp recordings to show that locomotion can be directly read out from mossy fiber synaptic input and spike output in single granule cells. The increase in granule cell spiking during locomotion is enhanced by glutamate spillover currents recruited during movement. Surprisingly, the entire step sequence can be predicted from input EPSCs and output spikes of a single granule cell, suggesting that a robust gait code is present already at the cerebellar input layer and transmitted via the granule cell pathway to downstream Purkinje cells. Thus, synaptic input delivers remarkably rich information to single neurons during locomotion. DOI: http://dx.doi.org/10.7554/eLife.07290.001 PMID:26083712

  13. EXTERIOR VIEW WITH HEART OF DIXIE MUSEUM'S HISTORIC LOCOMOTIVE IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    EXTERIOR VIEW WITH HEART OF DIXIE MUSEUM'S HISTORIC LOCOMOTIVE IN MUSEUM'S POWELL AVENUE YARD (BOTTOM) AND SOUTHERN RAILWAY BOXCAR ON ACTIVE TRACKAGE (ABOVE). - Heart of Dixie Railroad, Rolling Stock, 1800 Block Powell Avenue, Birmingham, Jefferson County, AL

  14. 10. Locomotive smoke flue coming through Roundhouse roof with gable ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Locomotive smoke flue coming through Roundhouse roof with gable end of Machine Shop in background. - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Roundhouse, Site Bounded by West Broad, Jones, West Boundary & Hull, Savannah, Chatham County, GA

  15. "Shower head" water connection for servicing railroad locomotives, perspective view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    "Shower head" water connection for servicing railroad locomotives, perspective view looking NW across ATSF railyard. - Grand Canyon Village Utilities, Grand Canyon National Park, Grand Canyon Village, Coconino County, AZ

  16. Breathing and locomotion: comparative anatomy, morphology and function.

    PubMed

    Klein, Wilfried; Codd, Jonathan R

    2010-08-31

    Using specialized respiratory structures such as gills, lungs and or a tracheal system, animals take up oxygen and release carbon dioxide. The efficiency of gas exchange, however, may be constrained by the morphology of the respiratory organ itself as well as by other aspects of an animal's physiology such as feeding, circulation or locomotion. Herein we discuss some aspects of the functional link between the respiratory and locomotor systems, such as gill morphology of sharks as a factor limiting maximum aerobic scope, respiratory constraints among legless lizards, lung morphology of testudines, trade-offs between locomotion and respiration among birds, reconstruction of the respiratory system of sauropods, respiration of mice during locomotion as well as some aspects of gas exchange among insects. Data covering such a broad spectrum of interactions between the locomotor and respiratory systems shall allow us to place breathing and locomotion into a wider context of evolution of oxygen. PMID:20417316

  17. Locomotion in Lymphocytes is Altered by Differential PKC Isoform Expression

    NASA Technical Reports Server (NTRS)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    1999-01-01

    Lymphocyte locomotion is critical for proper elicitation of the immune response. Locomotion of immune cells via the interstitium is essential for optimal immune function during wound healing, inflammation and infection. There are conditions which alter lymphocyte locomotion and one of them is spaceflight. Lymphocyte locomotion is severely inhibited in true spaceflight (true microgravity) and in rotating wall vessel culture (modeled microgravity). When lymphocytes are activated prior to culture in modeled microgravity, locomotion is not inhibited and the levels are comparable to those of static cultured lymphocytes. When a phorbol ester (PMA) is used in modeled microgravity, lymphocyte locomotion is restored by 87%. This occurs regardless if PMA is added after culture in the rotating wall vessel or during culture. Inhibition of DNA synthesis also does not alter restoration of lymphocyte locomotion by PMA. PMA is a direct activator of (protein kinase C) PKC . When a calcium ionophore, ionomycin is used it does not possess any restorative properties towards locomotion either alone or collectively with PMA. Since PMA brings about restoration without help from calcium ionophores (ionomycin), it is infer-red that calcium independent PKC isoforms are involved. Changes were perceived in the protein levels of PKC 6 where levels of the protein were downregulated at 24,72 and 96 hours in untreated rotated cultures (modeled microgravity) compared to untreated static (1g) cultures. At 48 hours there is an increase in the levels of PKC & in the same experimental set up. Studies on transcriptional and translational patterns of calcium independent isoforms of PKC such as 8 and E are presented in this study.

  18. EXTERIOR VIEW WITH HISTORIC LOCOMOTIVES, COAL AND PASSENGER CARS INCLUDING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    EXTERIOR VIEW WITH HISTORIC LOCOMOTIVES, COAL AND PASSENGER CARS INCLUDING THE WOODWARD IRON COMPANY NO. 38 LOCOMOTIVE AND TENDER LOCATED IN THE HEART OF DIXIE MUSEUM'S POWELL AVENUE YARD AND SOUTHERN RAILROAD BOXCARS ON ACTIVE TRACKS OF BIRMINGHAM'S RAILROAD RESERVATION. IN BACKGROUND AT RIGHT AND CENTER IS THE BIRMINGHAM CITY CENTER. - Heart of Dixie Railroad, Rolling Stock, 1800 Block Powell Avenue, Birmingham, Jefferson County, AL

  19. The Geometry of Locomotive Behavioral States in C. elegans

    PubMed Central

    Bjorness, Theresa; Greene, Robert; You, Young-Jai

    2013-01-01

    We develop a new hidden Markov model-based method to analyze C elegans locomotive behavior and use this method to quantitatively characterize behavioral states. In agreement with previous work, we find states corresponding to roaming, dwelling, and quiescence. However, we also find evidence for a continuum of intermediate states. We suggest that roaming, dwelling, and quiescence may best be thought of as extremes which, mixed in any proportion, define the locomotive repertoire of C elegans foraging and feeding behavior. PMID:23555813

  20. Serotonin Influences Locomotion in the Nudibranch Mollusc Melibe leonina

    PubMed Central

    LEWIS, STEFANIE L.; LYONS, DEBORAH E.; MEEKINS, TIFFANIE L.; NEWCOMB, JAMES M.

    2015-01-01

    Serotonin (5-HT) influences locomotion in many animals, from flatworms to mammals. This study examined the effects of 5-HT on locomotion in the nudibranch mollusc Melibe leonina (Gould, 1852). M. leonina exhibits two modes of locomotion, crawling and swimming. Animals were bath-immersed in a range of concentrations of 5-HT or injected with various 5-HT solutions into the hemolymph and then monitored for locomotor activity. In contrast to other gastropods studied, M. leonina showed no significant effect of 5-HT on the distance crawled or the speed of crawling. However, the highest concentration (10−3 mol l−1 for bath immersion and 10−5 mol l−1 for injection) significantly increased the time spent swimming and the swimming speed. The 5-HT receptor antagonist methysergide inhibited the influence of 5-HT on the overall amount of swimming but not on swimming speed. These results suggest that 5-HT influences locomotion at the behavioral level in M. leonina. In conjunction with previous studies on the neural basis of locomotion in M. leonina, these results also suggest that this species is an excellent model system for investigating the 5-HT modulation of locomotion. PMID:21712224

  1. Visuomotor Control of Human Adaptive Locomotion: Understanding the Anticipatory Nature

    PubMed Central

    Higuchi, Takahiro

    2013-01-01

    To maintain balance during locomotion, the central nervous system (CNS) accommodates changes in the constraints of spatial environment (e.g., existence of an obstacle or changes in the surface properties). Locomotion while modifying the basic movement patterns in response to such constraints is referred to as adaptive locomotion. The most powerful means of ensuring balance during adaptive locomotion is to visually perceive the environmental properties at a distance and modify the movement patterns in an anticipatory manner to avoid perturbation altogether. For this reason, visuomotor control of adaptive locomotion is characterized, at least in part, by its anticipatory nature. The purpose of the present article is to review the relevant studies which revealed the anticipatory nature of the visuomotor control of adaptive locomotion. The anticipatory locomotor adjustments for stationary and changeable environment, as well as the spatio-temporal patterns of gaze behavior to support the anticipatory locomotor adjustments are described. Such description will clearly show that anticipatory locomotor adjustments are initiated when an object of interest (e.g., a goal or obstacle) still exists in far space. This review also show that, as a prerequisite of anticipatory locomotor adjustments, environmental properties are accurately perceived from a distance in relation to individual’s action capabilities. PMID:23720647

  2. Advanced underground Vehicle Power and Control: The locomotive Research Platform

    SciTech Connect

    Vehicle Projects LLC

    2003-01-28

    Develop a fuelcell mine locomotive with metal-hydride hydrogen storage. Test the locomotive for fundamental limitations preventing successful commercialization of hydride fuelcells in underground mining. During Phase 1 of the DOE-EERE sponsored project, FPI and its partner SNL, completed work on the development of a 14.4 kW fuelcell power plant and metal-hydride energy storage. An existing battery-electric locomotive with similar power requirements, minus the battery module, was used as the base vehicle. In March 2001, Atlas Copco Wagner of Portland, OR, installed the fuelcell power plant into the base vehicle and initiated integration of the system into the vehicle. The entire vehicle returned to Sandia in May 2001 for further development and integration. Initial system power-up took place in December 2001. A revision to the original contract, Phase 2, at the request of DOE Golden Field Office, established Vehicle Projects LLC as the new prime contractor,. Phase 2 allowed industry partners to conduct surface tests, incorporate enhancements to the original design by SNL, perform an extensive risk and safety analysis, and test the fuelcell locomotive underground under representative production mine conditions. During the surface tests one of the fuelcell stacks exhibited reduced power output resulting in having to replace both fuelcell stacks. The new stacks were manufactured with new and improved technology resulting in an increase of the gross power output from 14.4 kW to 17 kW. Further work by CANMET and Hatch Associates, an engineering consulting firm specializing in safety analysis for the mining industry, both under subcontract to Vehicle Projects LLC, established minimum requirements for underground testing. CANMET upgraded the Programmable Logic Control (PLC) software used to monitor and control the fuelcell power plant, taking into account locomotive operator's needs. Battery Electric, a South Africa manufacturer, designed and manufactured (at no cost to

  3. [Locomotive syndrome and frailty. Osteoporosis as an underlying disorder in the locomotive syndrome].

    PubMed

    Hagino, Hiroshi

    2012-04-01

    Osteoporosis, a disorder related to locomotive syndrome, has been nicknamed "the silent disease" since it has no symptoms until fragility fracture occurs. However, a new fragility fracture cannot only reduce daily activity but can also increase fracture risk resulting in possible repetition of the fracture or other new fractures. As a result, daily living activities requiring mobility are often rapidly reduced and the quality of life can be considerably impaired. There are three strategies for preventing fragility fractures : prevention of falls, anti-osteoporosis treatment and hip protectors. A multidisciplinary approach including these strategies should be emphasized to impede the damaging process involved in fragility fracture. PMID:22460510

  4. Vestibular compensation and orientation during locomotion

    NASA Technical Reports Server (NTRS)

    Raphan, T.; Imai, T.; Moore, S. T.; Cohen, B.

    2001-01-01

    Body, head, and eye movements were studied in three dimensions while walking and turning to determine the role of the vestibular system in directing gaze and maintaining spatial orientation. The body, head, and eyes were represented as three-dimensional coordinate frames, and the movement of these frames was related to a trajectory frame that described the motion of the body on a terrestrial plane. The axis-angle of the body, head, and eye rotation were then compared to the axis-angle of the rotation of the gravitoinertial acceleration (GIA). We inferred the role of the vestibular system during locomotion and the contributions of the VCR and VOR by examining the interrelationship between these coordinate frames. Straight walking induced head and eye rotations in a compensatory manner to the linear accelerations, maintaining head pointing and gaze along the direction of forward motion. Turning generated a combination of compensation and orientation responses. The head leads and steers the turn while the eyes compensate to maintain stable horizontal gaze in space. Saccades shift horizontal gaze as the turn is executed. The head pitches, as during straight walking. It also rolls so that the head tends to align with the orientation of the GIA. Head orientation changes anticipate orientation changes of the GIA. Eye orientation follows the changes in GIA orientation so that the net orientation gaze is closer to the orientation of the GIA. The study indicates that the vestibular system utilizes compensatory and orienting mechanisms to stabilize spatial orientation and gaze during walking and turning.

  5. Legged-locomotion on inclined granular media

    NASA Astrophysics Data System (ADS)

    Rieser, Jennifer; Qian, Feifei; Goldman, Daniel

    Animals traverse a wide variety of complex environments, including situations in which the ground beneath them can yield (e.g. dry granular media in desert dunes). Locomotion strategies that are effective on level granular media can fail when traversing a granular slope. Taking inspiration from successful legged-locomotors in sandy, uneven settings, we explore the ability of a small (15 cm long, 100 g), six-c-shaped legged robot to run uphill in a bed of 1-mm-diameter poppy seeds, using an alternating tripod gait. Our fully automated experiments reveal that locomotor performance can depend sensitively on both environmental parameters such as the inclination angle and volume fraction of the substrate, and robot morphology and control parameters like leg shape, step frequency, and the friction between the feet of the robot and the substrate. We assess performance by measuring the average speed of the robot, and we find that the robot tends to perform better at higher step frequency and lower inclination angles, and that average speed decreases more rapidly with increasing angle for higher step frequency.

  6. Water surface locomotion in tropical canopy ants.

    PubMed

    Yanoviak, S P; Frederick, D N

    2014-06-15

    Upon falling onto the water surface, most terrestrial arthropods helplessly struggle and are quickly eaten by aquatic predators. Exceptions to this outcome mostly occur among riparian taxa that escape by walking or swimming at the water surface. Here we document sustained, directional, neustonic locomotion (i.e. surface swimming) in tropical arboreal ants. We dropped 35 species of ants into natural and artificial aquatic settings in Peru and Panama to assess their swimming ability. Ten species showed directed surface swimming at speeds >3 body lengths s(-1), with some swimming at absolute speeds >10 cm s(-1). Ten other species exhibited partial swimming ability characterized by relatively slow but directed movement. The remaining species showed no locomotory control at the surface. The phylogenetic distribution of swimming among ant genera indicates parallel evolution and a trend toward negative association with directed aerial descent behavior. Experiments with workers of Odontomachus bauri showed that they escape from the water by directing their swimming toward dark emergent objects (i.e. skototaxis). Analyses of high-speed video images indicate that Pachycondyla spp. and O. bauri use a modified alternating tripod gait when swimming; they generate thrust at the water surface via synchronized treading and rowing motions of the contralateral fore and mid legs, respectively, while the hind legs provide roll stability. These results expand the list of facultatively neustonic terrestrial taxa to include various species of tropical arboreal ants. PMID:24920838

  7. Visualizing the spinal neuronal dynamics of locomotion

    NASA Astrophysics Data System (ADS)

    Subramanian, Kalpathi R.; Bashor, D. P.; Miller, M. T.; Foster, J. A.

    2004-06-01

    Modern imaging and simulation techniques have enhanced system-level understanding of neural function. In this article, we present an application of interactive visualization to understanding neuronal dynamics causing locomotion of a single hip joint, based on pattern generator output of the spinal cord. Our earlier work visualized cell-level responses of multiple neuronal populations. However, the spatial relationships were abstract, making communication with colleagues difficult. We propose two approaches to overcome this: (1) building a 3D anatomical model of the spinal cord with neurons distributed inside, animated by the simulation and (2) adding limb movements predicted by neuronal activity. The new system was tested using a cat walking central pattern generator driving a pair of opposed spinal motoneuron pools. Output of opposing motoneuron pools was combined into a single metric, called "Net Neural Drive", which generated angular limb movement in proportion to its magnitude. Net neural drive constitutes a new description of limb movement control. The combination of spatial and temporal information in the visualizations elegantly conveys the neural activity of the output elements (motoneurons), as well as the resulting movement. The new system encompasses five biological levels of organization from ion channels to observed behavior. The system is easily scalable, and provides an efficient interactive platform for rapid hypothesis testing.

  8. Nematode locomotion in unconfined and confined fluids

    NASA Astrophysics Data System (ADS)

    Bilbao, Alejandro; Wajnryb, Eligiusz; Vanapalli, Siva A.; Blawzdziewicz, Jerzy

    2013-08-01

    The millimeter-long soil-dwelling nematode Caenorhabditis elegans propels itself by producing undulations that propagate along its body and turns by assuming highly curved shapes. According to our recent study [V. Padmanabhan et al., PLoS ONE 7, e40121 (2012), 10.1371/journal.pone.0040121] all these postures can be accurately described by a piecewise-harmonic-curvature model. We combine this curvature-based description with highly accurate hydrodynamic bead models to evaluate the normalized velocity and turning angles for a worm swimming in an unconfined fluid and in a parallel-wall cell. We find that the worm moves twice as fast and navigates more effectively under a strong confinement, due to the large transverse-to-longitudinal resistance-coefficient ratio resulting from the wall-mediated far-field hydrodynamic coupling between body segments. We also note that the optimal swimming gait is similar to the gait observed for nematodes swimming in high-viscosity fluids. Our bead models allow us to determine the effects of confinement and finite thickness of the body of the nematode on its locomotion. These effects are not accounted for by the classical resistive-force and slender-body theories.

  9. Stokesian locomotion in elastic fluids: Experiments

    NASA Astrophysics Data System (ADS)

    Zenit, Roberto; Lauga, Eric

    2010-11-01

    In many instances of biological relevance, self-propelled cells have to swim through non-Newtonian fluids. In order to provide fundamental understanding on the effect of such non-Newtonian stresses on locomotion, we have studied the motion an oscillating magnetic swimmer immersed in both Newtonian and non-Newtonian liquids at small Reynolds numbers. The swimmer is made with a small rare earth (Neodymium-Iron-Boron) magnetic rod (3 mm) to which a flexible tail was glued. This array was immersed in cylindrical container (50 mm diameter) in which the test fluid was contained. A nearly uniform oscillating magnetic field was created with a Helmholtz coil (R=200mm) and a AC power supply. For the Newtonian case, a 30,000 cSt silicon oil was used. In the non-Newtonian case, a fluid with nearly constant viscosity and large first normal stress difference (highly elastic) was used; this fluid was made with Corn syrup with a small amount of polyacrylamide. The swimming speed was measured, for different amplitudes and frequencies, using a digital image analysis. The objective of the present investigation is to determine whether the elastic effects of the fluid improve or not the swimming performance. Some preliminary results will be presented and discussed.

  10. Stability versus maneuverability in aquatic locomotion.

    PubMed

    Weihs, Daniel

    2002-02-01

    The dictionary definition of stability as "Firmly established, not easily to be changed" immediately indicates the conflict between stability and maneuverability in aquatic locomotion. The present paper addresses several issues resulting from these opposing requirements. Classical stability theory for bodies moving in fluids is based on developments in submarine and airship motions. These have lateral symmetry, in common with most animals. This enables the separation of the equations of motion into two sets of 3 each. The vertical (longitudinal) set, which includes motions in the axial (surge), normal (heave) and pitching directions, can thus be separated from the lateral-horizontal plane which includes yaw, roll and sideslip motions. This has been found useful in the past for longitudinal stability studies based on coasting configurations but is not applicable to the analysis of turning, fast starts and vigorous swimming, where the lateral symmetry of the fish body is broken by bending motions. The present paper will also examine some of the aspects of the stability vs. maneuverability tradeoff for these asymmetric motions. An analysis of the conditions under which the separation of equations of motions into vertical and horizontal planes is justified, and a definition of the equations to be used in cases where this separation is not accurate enough is presented. PMID:21708701

  11. Drosophila melanogaster locomotion in cold thin air.

    PubMed

    Dillon, Michael E; Frazier, Melanie R

    2006-01-01

    The alpine environment is likely to challenge insect locomotion because of low mean temperatures and reduced barometric pressure. In this study, we measured the direct and interactive effects of these factors on walking and flight performance of wild-caught Drosophila melanogaster Meigen. We found that decreased temperature and decreased air pressure both reduced walking speed and flight performance. Flies walked more slowly at 18 degrees C and in the lowest air pressure treatment (34 kPa). This treatment, equivalent in air pressure to the top of Mount Everest, was the only air pressure that significantly reduced fly walking speed. Therefore, walking performance in the wild is likely limited by temperature, but not oxygen availability. In contrast to walking performance, low but ecologically realistic air pressures dramatically reduced overall flight performance. The effects of reduced air pressure on flight performance were more pronounced at colder temperatures. Reduced flight performance in high altitude conditions was primarily driven by an increased reluctance for flies to initiate flight rather than outright failure to fly. Such reluctance to fly in high altitude conditions may in part explain the prevalence of aptery and brachyptery in high altitude insects. The observed interactive effects of temperature and air pressure on flight performance confirm the importance of simultaneously manipulating both of these factors when studying the impact of altitudinal conditions on insect physiology and behavior. PMID:16391358

  12. Intramuscular Pressure Measurement During Locomotion in Humans

    NASA Technical Reports Server (NTRS)

    Ballard, Ricard E.

    1996-01-01

    To assess the usefulness of intramuscular pressure (IMP) measurement for studying muscle function during gait, IMP was recorded in the soleus and tibialis anterior muscles of ten volunteers during, treadmill walking, and running using transducer-tipped catheters. Soleus IMP exhibited single peaks during late-stance phase of walking (181 +/- 69 mmHg, mean +/- S.E.) and running (269 +/- 95 mmHg). Tibialis anterior IMP showed a biphasic response, with the largest peak (90 +/- 15 mmHg during walking and 151 +/- 25 mmHg during running) occurring shortly after heel strike. IMP magnitude increased with gait speed in both muscles. Linear regression of soleus IMP against ankle joint torque obtained by a dynamometer in two subjects produced linear relationships (r = 0.97). Application of these relationships to IMP data yielded estimated peak soleus moment contributions of 0.95-165 Nm/Kg during walking, and 1.43-2.70 Nm/Kg during running. IMP results from local muscle tissue deformations caused by muscle force development and thus, provides a direct, practical index of muscle function during locomotion in humans.

  13. Leg intramuscular pressures during locomotion in humans

    NASA Technical Reports Server (NTRS)

    Ballard, R. E.; Watenpaugh, D. E.; Breit, G. A.; Murthy, G.; Holley, D. C.; Hargens, A. R.

    1998-01-01

    To assess the usefulness of intramuscular pressure (IMP) measurement for studying muscle function during gait, IMP was recorded in the soleus and tibialis anterior muscles of 10 volunteers during treadmill walking and running by using transducer-tipped catheters. Soleus IMP exhibited single peaks during late-stance phase of walking [181 +/- 69 (SE) mmHg] and running (269 +/- 95 mmHg). Tibialis anterior IMP showed a biphasic response, with the largest peak (90 +/- 15 mmHg during walking and 151 +/- 25 mmHg during running) occurring shortly after heel strike. IMP magnitude increased with gait speed in both muscles. Linear regression of soleus IMP against ankle joint torque obtained by a dynamometer produced linear relationships (n = 2, r = 0.97 for both). Application of these relationships to IMP data yielded estimated peak soleus moment contributions of 0.95-1.65 N . m/kg during walking, and 1.43-2.70 N . m/kg during running. Phasic elevations of IMP during exercise are probably generated by local muscle tissue deformations due to muscle force development. Thus profiles of IMP provide a direct, reproducible index of muscle function during locomotion in humans.

  14. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  15. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  16. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  17. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  18. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  19. Spontaneous combustion of hydrogen

    NASA Technical Reports Server (NTRS)

    Nusselt, Wilhelm; Pothmann, PH

    1923-01-01

    It is shown by the author's experiments that hydrogen which escapes to the atmosphere through openings in the system may burn spontaneously if it contains dust. Purely thermal reasoning can not account for the combustion. It seems to be rather an electrical ignition. In order to determine whether the cause of the spontaneous ignition was thermo-chemical, thermo-mechanical, or thermo-electrical, the experiments in this paper were performed.

  20. Manual and automatic locomotion scoring systems in dairy cows: a review.

    PubMed

    Schlageter-Tello, Andrés; Bokkers, Eddie A M; Koerkamp, Peter W G Groot; Van Hertem, Tom; Viazzi, Stefano; Romanini, Carlos E B; Halachmi, Ilan; Bahr, Claudia; Berckmans, Daniël; Lokhorst, Kees

    2014-09-01

    clear definition of a lameness case difficult, and thus affect the validity of ALSSs. MLSSs and ALSSs showed limited validity for hoof lesion detection and pain assessment. The utilization of MLSSs and ALSSs should aim to the prevention and efficient management of conditions that induce impaired locomotion. Long-term studies comparing MLSSs and ALSSs while applying various strategies to detect and control unfavourable conditions leading to impaired locomotion are required to determine the usefulness of MLSSs and ALSSs for securing optimal production and animal welfare in practice. PMID:25000863

  1. The behavioral space of zebrafish locomotion and its neural network model

    NASA Astrophysics Data System (ADS)

    Girdhar, Kiran; Benitez-Jones, Maria; Thi, Ha Pham; Nelson, Mark; Gruebele, Martin; Chemla, Yann

    2014-03-01

    How does one describe quantitatively the complex motion of vertebrates? To answer this question, we investigated a model system for vertebrate locomotion: zebrafish swimming. We performed a quantitative analysis of all stereotyped behavioral swimming patterns of zebrafish larvae: spontaneous swimming, escape response to stimulus, and prey tracking. Previous attempts to analyze zebrafish swimming motion quantitatively have imposed many arbitrary parameters. Here, we instead used a parameter-independent method that produces an orthogonal set of ``eigen-shapes'' of fish backbones to describe swimming motion in a low-dimensional space. We show that a linear combination of only three such ``eigen-shapes'' is sufficient to describe 97% of zebrafish shapes. Moreover, stereotyped swimming behaviors fall on two low-dimensional attractors embedded in this three dimensional behavioral space. We also show using a two-dimensional correlation analysis that ``scoots'' and ``R-turns,'' which were previously described as discrete behavioral states, in fact represent extrema in a continuum in this low-dimensional behavioral space. To understand the neural basis of the behavior, we have also developed a neural network model of spontaneous swimming of fish larvae. We present a set of neural parameters such as synaptic conductance, stimulus amplitude that produces swimming behavior and reconstructed the low-dimensional behavioral space obtained from experimental results.

  2. Cytoskeletal Mechanics Regulating Amoeboid Cell Locomotion

    PubMed Central

    Álvarez-González, Begoña; Meili, Ruedi; Firtel, Richard; Bastounis, Effie; del Álamo, Juan C.; Lasheras, Juan C.

    2014-01-01

    Migrating cells exert traction forces when moving. Amoeboid cell migration is a common type of cell migration that appears in many physiological and pathological processes and is performed by a wide variety of cell types. Understanding the coupling of the biochemistry and mechanics underlying the process of migration has the potential to guide the development of pharmacological treatment or genetic manipulations to treat a wide range of diseases. The measurement of the spatiotemporal evolution of the traction forces that produce the movement is an important aspect for the characterization of the locomotion mechanics. There are several methods to calculate the traction forces exerted by the cells. Currently the most commonly used ones are traction force microscopy methods based on the measurement of the deformation induced by the cells on elastic substrate on which they are moving. Amoeboid cells migrate by implementing a motility cycle based on the sequential repetition of four phases. In this paper we review the role that specific cytoskeletal components play in the regulation of the cell migration mechanics. We investigate the role of specific cytoskeletal components regarding the ability of the cells to perform the motility cycle effectively and the generation of traction forces. The actin nucleation in the leading edge of the cell, carried by the ARP2/3 complex activated through the SCAR/WAVE complex, has shown to be fundamental to the execution of the cyclic movement and to the generation of the traction forces. The protein PIR121, a member of the SCAR/WAVE complex, is essential to the proper regulation of the periodic movement and the protein SCAR, also included in the SCAR/WAVE complex, is necessary for the generation of the traction forces during migration. The protein Myosin II, an important F-actin cross-linker and motor protein, is essential to cytoskeletal contractility and to the generation and proper organization of the traction forces during

  3. Forelimb muscle activity during equine locomotion.

    PubMed

    Harrison, Simon M; Whitton, R Chris; King, Melissa; Haussler, Kevin K; Kawcak, Chris E; Stover, Susan M; Pandy, Marcus G

    2012-09-01

    Few quantitative data exist to describe the activity of the distal muscles of the equine forelimb during locomotion, and there is an incomplete understanding of the functional roles of the majority of the forelimb muscles. Based on morphology alone it would appear that the larger proximal muscles perform the majority of work in the forelimb, whereas the smaller distal muscles fulfil supplementary roles such as stabilizing the joints and positioning the limb for impact with the ground. We measured the timing and amplitude of the electromyographic activity of the intrinsic muscles of the forelimb in relation to the phase of gait (stance versus swing) and the torque demand placed on each joint during walking, trotting and cantering. We found that all forelimb muscles, except the extensor carpi radialis (ECR), were activated just prior to hoof-strike and deactivated during stance. Only the ECR was activated during swing. The amplitudes of muscle activation typically increased as gait speed increased. However, the amplitudes of muscle activation were not proportional to the net joint torques, indicating that passive structures may also contribute significantly to torque generation. Our results suggest that the smaller distal muscles help to stabilize the forelimb in early stance, in preparation for the passive structures (tendons and ligaments) to be stretched. The distal forelimb muscles remain active throughout stance only during canter, when the net torques acting about the distal forelimb joints are highest. The larger proximal muscles activate in a complex coordination to position and stabilize the shoulder and elbow joints during ground contact. PMID:22875767

  4. Spontaneous Language Markers of Spanish Language Impairment

    ERIC Educational Resources Information Center

    Simon-Cereijido, Gabriela; Gutierrez-Clellen, Vera F.

    2007-01-01

    Spanish-speaking (SS) children with language impairment (LI) present with deficits in morphology and verb argument structure. These language areas may be useful for clinical identification of affected children. This study aimed to evaluate the discrimination accuracy of spontaneous language measures with SS preschoolers to tease out what…

  5. Macrovascular Lesions Underlying Spontaneous Intracerebral Hemorrhage.

    PubMed

    Yeung, Jacky; Cord, Branden J; O'Rourke, Timothy K; Maina, Renee M; Sommaruga, Samuel; Matouk, Charles C

    2016-06-01

    Spontaneous intracerebral hemorrhage (ICH) is a morbid disease with a high case fatality rate. Prognosis, rehemorrhage rates, and acute, clinical decision making are greatly affected by the underlying etiology of hemorrhage. This review focuses on the evaluation, diagnosis, and management of structural, macrovascular lesions presenting with ICH, including ruptured aneurysms, brain arteriovenous malformations, cranial dural arteriovenous fistulas, and cerebral cavernous malformations. PMID:27214699

  6. EphA4-Mediated Ipsilateral Corticospinal Tract Misprojections Are Necessary for Bilateral Voluntary Movements But Not Bilateral Stereotypic Locomotion

    PubMed Central

    Serradj, Najet; Paixão, Sónia; Sobocki, Tomasz; Feinberg, Mitchell; Klein, Rüdiger; Kullander, Klas

    2014-01-01

    In this study, we took advantage of the reported role of EphA4 in determining the contralateral spinal projection of the corticospinal tract (CST) to investigate the effects of ipsilateral misprojections on voluntary movements and stereotypic locomotion. Null EphA4 mutations produce robust ipsilateral CST misprojections, resulting in bilateral corticospinal tracts. We hypothesize that a unilateral voluntary limb movement, not a stereotypic locomotor movement, will become a bilateral movement in EphA4 knock-out mice with a bilateral CST. However, in EphA4 full knock-outs, spinal interneurons also develop bilateral misprojections. Aberrant bilateral spinal circuits could thus transform unilateral corticospinal control signals into bilateral movements. We therefore studied mice with conditional forebrain deletion of the EphA4 gene under control by Emx1, a gene expressed in the forebrain that affects the developing CST but spares brainstem motor pathways and spinal motor circuits. We examined two conditional knock-outs targeting forebrain EphA4 during performance of stereotypic locomotion and voluntary movement: adaptive locomotion over obstacles and exploratory reaching. We found that the conditional knock-outs used alternate stepping, not hopping, during overground locomotion, suggesting normal central pattern generator function and supporting our hypothesis of minimal CST involvement in the moment-to-moment control of stereotypic locomotion. In contrast, the conditional knock-outs showed bilateral voluntary movements under conditions when single limb movements are normally produced and, as a basis for this aberrant control, developed a bilateral motor map in motor cortex that is driven by the aberrant ipsilateral CST misprojections. Therefore, a specific change in CST connectivity is associated with and explains a change in voluntary movement. PMID:24719100

  7. Autonomous locomotion of capsule endoscope in gastrointestinal tract.

    PubMed

    Yang, Sungwook; Park, Kitae; Kim, Jinseok; Kim, Tae Song; Cho, Il-Joo; Yoon, Eui-Sung

    2011-01-01

    Autonomous locomotion in gastrointestinal (GI) tracts is achieved with a paddling-based capsule endoscope. For this, a miniaturized encoder module was developed utilizing a MEMS fabrication technology to monitor the position of paddles. The integrated encoder module yielded the high resolution of 0.0025 mm in the linear motion of the paddles. In addition, a PID control method was implemented on a DSP to control the stroke of the paddles accurately. As a result, the average accuracy and the standard deviation were measured to be 0.037 mm and 0.025 mm by a laser position sensor for the repetitive measurements. The locomotive performance was evaluated via ex-vivo tests according to various strokes in paddling. In an in-vivo experiment with a living pig, the locomotion speed was improved by 58% compared with the previous control method relying on a given timer value for reciprocation of the paddles. Finally, the integrated encoder module and the control system allow consistent paddling during locomotion even under loads in GI tract. It provides the autonomous locomotion without intervention in monitoring and controlling the capsule endoscope. PMID:22255866

  8. Locomotion of neutrally buoyant fish with flexible caudal fin.

    PubMed

    Iosilevskii, Gil

    2016-06-21

    Historically, burst-and-coast locomotion strategies have been given two very different explanations. The first one was based on the assumption that the drag of an actively swimming fish is greater than the drag of the same fish in motionless glide. Fish reduce the cost of locomotion by swimming actively during a part of the swimming interval, and gliding through the remaining part. The second one was based on the assumption that muscles perform efficiently only if their contraction rate exceeds a certain threshold. Fish reduce the cost of locomotion by using an efficient contraction rate during a part of the swimming interval, and gliding through the remaining part. In this paper, we suggest yet a third explanation. It is based on the assumption that propulsion efficiency of a swimmer can increase with thrust. Fish reduce the cost of locomotion by alternating high thrust, and hence more efficient, bursts with passive glides. The paper presents a formal analysis of the respective burst-and-coast strategy, shows that the locomotion efficiency can be practically as high as the propulsion efficiency during burst, and shows that the other two explanations can be considered particular cases of the present one. PMID:27067246

  9. 49 CFR Appendix B to Part 240 - Procedures for Submission and Approval of Locomotive Engineer Qualification Programs

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Locomotive Engineer Qualification Programs B Appendix B to Part 240 Transportation Other Regulations Relating... Submission and Approval of Locomotive Engineer Qualification Programs This appendix establishes procedures... evaluating of persons seeking certification or recertification as a locomotive engineer in accordance...

  10. Biomodal spontaneous fission

    SciTech Connect

    Hulet, E.K. )

    1989-09-26

    Investigations of mass and kinetic-energy distributions from spontaneous fission have been extended in recent years to an isotope of element 104 and, for half-lives, to an isotope of element 108. The results have been surprising in that spontaneous fission half-lives have turned out to be much longer than expected and mass and kinetic- energy distributions were found to abruptly shift away from those of the lighter actinides, showing two modes of fission. These new developments have caused a re-evaluation of our understanding of the fission process, bringing an even deeper appreciation of the role played by nuclear shell effects upon spontaneous fission properties. 16 refs., 10 figs.

  11. Spontaneous hypnotic age regression: case report.

    PubMed

    Spiegel, D; Rosenfeld, A

    1984-12-01

    Age regression--reliving the past as though it were occurring in the present, with age appropriate vocabulary, mental content, and affect--can occur with instruction in highly hypnotizable individuals, but has rarely been reported to occur spontaneously, especially as a primary symptom. The psychiatric presentation and treatment of a 16-year-old girl with spontaneous age regressions accessible and controllable with hypnosis and psychotherapy are described. Areas of overlap and divergence between this patient's symptoms and those found in patients with hysterical fugue and multiple personality syndrome are also discussed. PMID:6501240

  12. Local reflexive mechanisms essential for snakes' scaffold-based locomotion.

    PubMed

    Kano, Takeshi; Sato, Takahide; Kobayashi, Ryo; Ishiguro, Akio

    2012-12-01

    Most robots are designed to work in predefined environments, and irregularities that exist in the environment interfere with their operation. For snakes, irregularities play the opposite role: snakes actively utilize terrain irregularities and move by effectively pushing their body against the scaffolds that they encounter. Autonomous decentralized control mechanisms could be the key to understanding this locomotion. We demonstrate through modelling and simulations that only two local reflexive mechanisms, which exploit sensory information about the stretching of muscles and the pressure on the body wall, are crucial for realizing locomotion. This finding will help develop robots that work in undefined environments and shed light on the understanding of the fundamental principles underlying adaptive locomotion in animals. PMID:22918023

  13. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion II

    NASA Astrophysics Data System (ADS)

    Lee, Scott

    2015-03-01

    In the second paper1 of this series, the effect of transverse femoral stresses due to locomotion in theropod dinosaurs of different sizes was examined for the case of an unchanging leg geometry. Students are invariably thrilled to learn about theropod dinosaurs, and this activity applies the concepts of torque and stress to the issue of theropod locomotion. In this paper, our model calculation of Ref. 1 is extended to incorporate the fact that larger animals run with straighter legs. As in Ref. 1, students use geometric data for the femora of theropod dinosaurs to analyze their locomotion abilities. This can either be an in-class activity or given as a homework problem. Larger theropods are found to be less athletic in their movements than smaller theropods since the stresses in the femora of large theropods are closer to breaking their legs than smaller theropods.

  14. A PHYSIOLOGIST'S PERSPECTIVE ON ROBOTIC EXOSKELETONS FOR HUMAN LOCOMOTION.

    PubMed

    Ferris, Daniel P; Sawicki, Gregory S; Daley, Monica A

    2007-09-01

    Technological advances in robotic hardware and software have enabled powered exoskeletons to move from science fiction to the real world. The objective of this article is to emphasize two main points for future research. First, the design of future devices could be improved by exploiting biomechanical principles of animal locomotion. Two goals in exoskeleton research could particularly benefit from additional physiological perspective: 1) reduction in the metabolic energy expenditure of the user while wearing the device, and 2) minimization of the power requirements for actuating the exoskeleton. Second, a reciprocal potential exists for robotic exoskeletons to advance our understanding of human locomotor physiology. Experimental data from humans walking and running with robotic exoskeletons could provide important insight into the metabolic cost of locomotion that is impossible to gain with other methods. Given the mutual benefits of collaboration, it is imperative that engineers and physiologists work together in future studies on robotic exoskeletons for human locomotion. PMID:18185840

  15. High-content screening assay for identification of chemicals impacting spontaneous activity in zebrafish embryos.

    PubMed

    Raftery, Tara D; Isales, Gregory M; Yozzo, Krystle L; Volz, David C

    2014-01-01

    Although cell-based assays exist, rapid and cost-efficient high-content screening (HCS) assays within intact organisms are needed to support prioritization for developmental neurotoxicity testing in rodents. During zebrafish embryogenesis, spontaneous tail contractions occur from late-segmentation (∼19 h postfertilization, hpf) through early pharyngula (∼29 hpf) and represent the first sign of locomotion. Using transgenic zebrafish (fli1:egfp) that stably express eGFP beginning at ∼14 hpf, we have developed and optimized a 384-well-based HCS assay that quantifies spontaneous activity within single zebrafish embryos after exposure to test chemicals in a concentration-response format. Following static exposure of one embryo per well from 5 to 25 hpf, automated image acquisition procedures and custom analysis protocols were used to quantify total body area and spontaneous activity in live embryos. Survival and imaging success rates across control plates ranged from 87.5 to 100% and 93.3-100%, respectively. Using our optimized procedures, we screened 16 chemicals within the US EPA's ToxCast Phase-I library, and found that exposure to abamectin and emamectin benzoate-both potent avermectins-abolished spontaneous activity in the absence of gross malformations. Overall, compared to existing locomotion-based zebrafish assays conducted later in development, this method provides a simpler discovery platform for identifying potential developmental neurotoxicants. PMID:24328182

  16. Spontaneous sarcomere dynamics

    NASA Astrophysics Data System (ADS)

    Günther, Stefan; Kruse, Karsten

    2010-12-01

    Sarcomeres are the basic force generating units of striated muscles and consist of an interdigitating arrangement of actin and myosin filaments. While muscle contraction is usually triggered by neural signals, which eventually set myosin motors into motion, isolated sarcomeres can oscillate spontaneously between a contracted and a relaxed state. We analyze a model for sarcomere dynamics, which is based on a force-dependent detachment rate of myosin from actin. Our numerical bifurcation analysis of the spontaneous sarcomere dynamics reveals notably Hopf bifurcations, canard explosions, and gluing bifurcations. We discuss possible implications for experiments.

  17. Quantifying coordination between the head and the trunk during locomotion

    NASA Astrophysics Data System (ADS)

    Mulavara, Ajitkumar P.

    This study developed unique measures of coordination between the head and the trunk during the combined tasks of locomotion and gaze fixation of visual targets. These measures will be used to determine the effects of long-duration space flight on sensorimotor function. This will enable evaluation of the efficacy of countermeasures and postflight rehabilitation programs. Indices were proposed as composite measures reflecting the functional aspects of the control system involved in gaze fixation during locomotion. The stiffness index (Nm/deg) was calculated as the ratio between the change in the magnitude of the net relative moments to the change in magnitude of the relative angular motion. The viscosity index (Nm-sec/deg) was calculated as the ratio between the change in the magnitude of the net relative moments to the change in magnitude of the relative angular velocity. These coordination measures were used to evaluate the normal dynamic pattern of coordination between the head and the trunk with respect to the events occurring in a gait cycle. The indices were evaluated for three discrete speeds of locomotion for the same gaze fixation task and for three discrete gaze fixation tasks at the same speed of locomotion. The indices were found to be repeatable measures reflecting inter-segmental coordination strategies while performing an activity of daily living. These indices showed that the coordination of the head with respect to the trunk was significantly different between the events of heel strike and swing phases during the gait cycle. These indices showed no significant differences between the different gaze fixation tasks. The speed of locomotion had a significant effect on the magnitude of these indices. The results indicate that the CNS dynamically modulates head motion with respect to the trunk dependent on the events occurring during the gait cycle. This modulation is appropriate for stabilizing gaze during locomotion. The results support the hypothesis

  18. Insects Use Two Distinct Classes of Steps during Unrestrained Locomotion

    PubMed Central

    Theunissen, Leslie M.; Dürr, Volker

    2013-01-01

    Background Adaptive, context-dependent control of locomotion requires modulation of centrally generated rhythmic motor patterns through peripheral control loops and postural reflexes. Thus assuming that the modulation of rhythmic motor patterns accounts for much of the behavioural variability observed in legged locomotion, investigating behavioural variability is a key to the understanding of context-dependent control mechanisms in locomotion. To date, the variability of unrestrained locomotion is poorly understood, and virtually nothing is known about the features that characterise the natural statistics of legged locomotion. In this study, we quantify the natural variability of hexapedal walking and climbing in insects, drawing from a database of several thousand steps recorded over two hours of walking time. Results We show that the range of step length used by unrestrained climbing stick insects is large, showing that step length can be changed substantially for adaptive locomotion. Step length distributions were always bimodal, irrespective of leg type and walking condition, suggesting the presence of two distinct classes of steps: short and long steps. Probability density of step length was well-described by a gamma distribution for short steps, and a logistic distribution for long steps. Major coefficients of these distributions remained largely unaffected by walking conditions. Short and long steps differed concerning their spatial occurrence on the walking substrate, their timing within the step sequence, and their prevalent swing direction. Finally, ablation of structures that serve to improve foothold increased the ratio of short to long steps, indicating a corrective function of short steps. Conclusions Statistical and functional differences suggest that short and long steps are physiologically distinct classes of leg movements that likely reflect distinct control mechanisms at work. PMID:24376877

  19. Postural dependence of human locomotion during gait initiation.

    PubMed

    Mille, Marie-Laure; Simoneau, Martin; Rogers, Mark W

    2014-12-15

    The initiation of human walking involves postural motor actions for body orientation and balance stabilization that must be effectively integrated with locomotion to allow safe and efficient transport. Our ability to coordinately adapt these functions to environmental or bodily changes through error-based motor learning is essential to effective performance. Predictive compensations for postural perturbations through anticipatory postural adjustments (APAs) that stabilize mediolateral (ML) standing balance normally precede and accompany stepping. The temporal sequencing between these events may involve neural processes that suppress stepping until the expected stability conditions are achieved. If so, then an unexpected perturbation that disrupts the ML APAs should delay locomotion. This study investigated how the central nervous system (CNS) adapts posture and locomotion to perturbations of ML standing balance. Healthy human adults initiated locomotion while a resistance force was applied at the pelvis to perturb posture. In experiment 1, using random perturbations, step onset timing was delayed relative to the APA onset indicating that locomotion was withheld until expected stability conditions occurred. Furthermore, stepping parameters were adapted with the APAs indicating that motor prediction of the consequences of the postural changes likely modified the step motor command. In experiment 2, repetitive postural perturbations induced sustained locomotor aftereffects in some parameters (i.e., step height), immediate but rapidly readapted aftereffects in others, or had no aftereffects. These results indicated both rapid but transient reactive adaptations in the posture and gait assembly and more durable practice-dependent changes suggesting feedforward adaptation of locomotion in response to the prevailing postural conditions. PMID:25231611

  20. Activity of motor cortex neurons during backward locomotion

    PubMed Central

    Deliagina, T. G.; Orlovsky, G. N.; Karayannidou, A.; Stout, E. E.; Sirota, M. G.; Beloozerova, I. N.

    2011-01-01

    Forward walking (FW) and backward walking (BW) are two important forms of locomotion in quadrupeds. Participation of the motor cortex in the control of FW has been intensively studied, whereas cortical activity during BW has never been investigated. The aim of this study was to analyze locomotion-related activity of the motor cortex during BW and compare it with that during FW. For this purpose, we recorded activity of individual neurons in the cat during BW and FW. We found that the discharge frequency in almost all neurons was modulated in the rhythm of stepping during both FW and BW. However, the modulation patterns during BW and FW were different in 80% of neurons. To determine the source of modulating influences (forelimb controllers vs. hindlimb controllers), the neurons were recorded not only during quadrupedal locomotion but also during bipedal locomotion (with either forelimbs or hindlimbs walking), and their modulation patterns were compared. We found that during BW (like during FW), modulation in some neurons was determined by inputs from limb controllers of only one girdle, whereas the other neurons received inputs from both girdles. The combinations of inputs could depend on the direction of locomotion. Most often (in 51% of forelimb-related neurons and in 34% of the hindlimb-related neurons), the neurons received inputs only from their own girdle when this girdle was leading and from both girdles when this girdle was trailing. This reconfiguration of inputs suggests flexibility of the functional roles of individual cortical neurons during different forms of locomotion. PMID:21430283

  1. [Locomotion and control study on autonomous interventional diagnostic micro-robots].

    PubMed

    Gu, Da-qiang; Zhou, Yong

    2008-09-01

    This paper introduces the locomotion control and the research status of the autonomous interventional diagnostic micro-robots in detail, outlines technical problems and difficulties now existing, and discusses the developing trend of locomotion control. PMID:19119659

  2. Track train dynamics analysis and test program: Locomotive dynamic characterization summary

    NASA Technical Reports Server (NTRS)

    Berry, R. L.

    1982-01-01

    Locomotive mechanical characteristics, track perturbations, and operational characteristics involving experimentally determined suspension system parameters are analyzed. Suspension bearings, shock absorbers, pads, and two- and three- axle trucks are comparatively evaluated with respect to locomotive design.

  3. Biorobotics: using robots to emulate and investigate agile locomotion.

    PubMed

    Ijspeert, Auke J

    2014-10-10

    The graceful and agile movements of animals are difficult to analyze and emulate because locomotion is the result of a complex interplay of many components: the central and peripheral nervous systems, the musculoskeletal system, and the environment. The goals of biorobotics are to take inspiration from biological principles to design robots that match the agility of animals, and to use robots as scientific tools to investigate animal adaptive behavior. Used as physical models, biorobots contribute to hypothesis testing in fields such as hydrodynamics, biomechanics, neuroscience, and prosthetics. Their use may contribute to the design of prosthetic devices that more closely take human locomotion principles into account. PMID:25301621

  4. Economic aspects of advanced coal-fired gas turbine locomotives

    NASA Technical Reports Server (NTRS)

    Liddle, S. G.; Bonzo, B. B.; Houser, B. C.

    1983-01-01

    Increases in the price of such conventional fuels as Diesel No. 2, as well as advancements in turbine technology, have prompted the present economic assessment of coal-fired gas turbine locomotive engines. A regenerative open cycle internal combustion gas turbine engine may be used, given the development of ceramic hot section components. Otherwise, an external combustion gas turbine engine appears attractive, since although its thermal efficiency is lower than that of a Diesel engine, its fuel is far less expensive. Attention is given to such a powerplant which will use a fluidized bed coal combustor. A life cycle cost analysis yields figures that are approximately half those typical of present locomotive engines.

  5. A rolling locomotion method for untethered magnetic microrobots

    NASA Astrophysics Data System (ADS)

    Hou, Max T.; Shen, Hui-Mei; Jiang, Guan-Lin; Lu, Chiang-Ni; Hsu, I.-Jen; Yeh, J. Andrew

    2010-01-01

    It is a challenge to achieve free and efficient motion of microrobots on arbitrary surfaces. We report a rolling locomotion method for a magnetic microrobot with a rectangular body (300×200×50 μm3); this method is based on an external rotating magnetic field. The magnetic force, accompanied by normal and friction forces, enables the successive rotations of the microrobot. A magnetic field with a rotational speed of 2 rps rolls the microrobot, giving it a translation speed of 1.4 mm/s. With this locomotion ability, microrobots can move along a line or curve and can climb slopes or stairs.

  6. Locomotive Emission and Engine Idle Reduction Technology Demonstration Project

    SciTech Connect

    John R. Archer

    2005-03-14

    In response to a United States Department of Energy (DOE) solicitation, the Maryland Energy Administration (MEA), in partnership with CSX Transportation, Inc. (CSXT), submitted a proposal to DOE to support the demonstration of Auxiliary Power Unit (APU) technology on fifty-six CSXT locomotives. The project purpose was to demonstrate the idle fuel savings, the Nitrous Oxide (NOX) emissions reduction and the noise reduction capabilities of the APU. Fifty-six CSXT Baltimore Division locomotives were equipped with APUs, Engine Run Managers (ERM) and communications equipment to permit GPS tracking and data collection from the locomotives. Throughout the report there is mention of the percent time spent in the State of Maryland. The fifty-six locomotives spent most of their time inside the borders of Maryland and some spent all their time inside the state borders. Usually when a locomotive traveled beyond the Maryland State border it was into an adjoining state. They were divided into four groups according to assignment: (1) Power Unit/Switcher Mate units, (2) Remote Control units, (3) SD50 Pusher units and (4) Other units. The primary data of interest were idle data plus the status of the locomotive--stationary or moving. Also collected were main engine off, idling or working. Idle data were collected by county location, by locomotive status (stationary or moving) and type of idle (Idle 1, main engine idling, APU off; Idle 2, main engine off, APU on; Idle 3, main engine off, APU off; Idle 4, main engine idle, APU on). Desirable main engine idle states are main engine off and APU off or main engine off and APU on. Measuring the time the main engine spends in these desirable states versus the total time it could spend in an engine idling state allows the calculation of Percent Idle Management Effectiveness (%IME). IME is the result of the operation of the APU plus the implementation of CSXT's Warm Weather Shutdown Policy. It is difficult to separate the two. The units

  7. Decoding the organization of spinal circuits that control locomotion

    PubMed Central

    Kiehn, Ole

    2016-01-01

    Unravelling the functional operation of neuronal networks and linking cellular activity to specific behavioural outcomes are among the biggest challenges in neuroscience. In this broad field of research, substantial progress has been made in studies of the spinal networks that control locomotion. Through united efforts using electrophysiological and molecular genetic network approaches and behavioural studies in phylogenetically diverse experimental models, the organization of locomotor networks has begun to be decoded. The emergent themes from this research are that the locomotor networks have a modular organization with distinct transmitter and molecular codes and that their organization is reconfigured with changes to the speed of locomotion or changes in gait. PMID:26935168

  8. The control of ventilation is dissociated from locomotion during walking in sheep

    PubMed Central

    Haouzi, Philippe; Chenuel, Bruno; Chalon, Bernard

    2004-01-01

    This study was designed to test the hypothesis that the frequency response of the systems controlling the motor activity of breathing and walking in quadrupeds is compatible with the idea that supra-spinal locomotor centres could proportionally drive locomotion and ventilation. The locomotor and the breath-by-breath ventilatory and gas exchange (CO2 output (V̇CO2) and O2 uptake (V̇CO2)) responses were studied in five sheep spontaneously walking on a treadmill. The speed of the treadmill was changed in a sinusoidal pattern of various periods (from 10 to 1 minute) and in a step-like manner. The frequency and amplitude of the limb movements, oscillating at the same period as the treadmill speed changes, had a constant gain with no phase lag (determined by Fourier analysis) regardless the periods of oscillations. In marked contrast, when the periods of speed oscillations decreased, the amplitude (peak-to-mean) of minute ventilation (V̇E) oscillations decreased sharply and significantly (from 6.1 ± 0.4 l min−1 to 1.9 ± 0.2 l min−1) and the phase lag between ventilation and treadmill speed oscillations increased (to 105 ± 25 ° during the 1 min oscillation periods). V̇E response followed V̇CO2 very closely. The drop in V̇E amplitude ratio was proportional to that in V̇CO2 (from 149 ± 48 ml min−1 to 38 ± 5 ml min−1) with a slightly longer phase lag for ventilation than for V̇CO2. These results show that beyond the onset period of a locomotor activity, the amplitude and phase lag of the V̇E response depends on the period of the walking speed oscillations, tracking the gas exchange rate, regardless of the amplitude of the motor act of walking. Locomotion thus appears unlikely to cause a simple parallel and proportional increase in ventilation in walking sheep. PMID:15235099

  9. Microfluidic-based electrotaxis for on-demand quantitative analysis of Caenorhabditis elegans' locomotion.

    PubMed

    Tong, Justin; Rezai, Pouya; Salam, Sangeena; Selvaganapathy, P Ravi; Gupta, Bhagwati P

    2013-01-01

    The nematode Caenorhabditis elegans is a versatile model organism for biomedical research because of its conservation of disease-related genes and pathways as well as its ease of cultivation. Several C. elegans disease models have been reported, including neurodegenerative disorders such as Parkinson's disease (PD), which involves the degeneration of dopaminergic (DA) neurons (1). Both transgenes and neurotoxic chemicals have been used to induce DA neurodegeneration and consequent movement defects in worms, allowing for investigations into the basis of neurodegeneration and screens for neuroprotective genes and compounds (2,3). Screens in lower eukaryotes like C. elegans provide an efficient and economical means to identify compounds and genes affecting neuronal signaling. Conventional screens are typically performed manually and scored by visual inspection; consequently, they are time-consuming and prone to human errors. Additionally, most focus on cellular level analysis while ignoring locomotion, which is an especially important parameter for movement disorders. We have developed a novel microfluidic screening system (Figure 1) that controls and quantifies C. elegans' locomotion using electric field stimuli inside microchannels. We have shown that a Direct Current (DC) field can robustly induce on-demand locomotion towards the cathode ("electrotaxis") (4). Reversing the field's polarity causes the worm to quickly reverse its direction as well. We have also shown that defects in dopaminergic and other sensory neurons alter the swimming response (5). Therefore, abnormalities in neuronal signaling can be determined using locomotion as a read-out. The movement response can be accurately quantified using a range of parameters such as swimming speed, body bending frequency and reversal time. Our work has revealed that the electrotactic response varies with age. Specifically, young adults respond to a lower range of electric fields and move faster compared to larvae (4

  10. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  11. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  12. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  13. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  14. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  15. Spontaneous otogenic pneumocephalus.

    PubMed

    Mohammed, El Romyssa; Profant, Milan

    2011-06-01

    The diagnosis and management of spontaneous otogenic pneumocephalus with literature review is described. A young sportsman experienced headache and fluctuating mass in his occiput during increased physical activity. A large extradural intracranial pneumocephalus with corresponding emphysema was imaged on a CT scan. Transmastoid identification and plugging of temporal bone defect solved the problem with complete pneumocephalus and emphysema resorption. PMID:21254960

  16. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with...

  17. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with...

  18. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with...

  19. 40 CFR Appendix I to Part 92 - Emission Related Locomotive and Engine Parameters and Specifications

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Emission Related Locomotive and Engine Parameters and Specifications I Appendix I to Part 92 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Pt. 92, App. I Appendix I to...

  20. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  1. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  2. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  3. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  4. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  5. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  6. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Specifications common to all steam locomotives... Specifications common to all steam locomotives. (a) Hand brakes. (1) Hand brakes will not be required on...) Locomotives having headlights which can not be safely and conveniently reached from pilot-beam or steam...

  7. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Specifications common to all steam locomotives... Specifications common to all steam locomotives. (a) Hand brakes. (1) Hand brakes will not be required on...) Locomotives having headlights which can not be safely and conveniently reached from pilot-beam or steam...

  8. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Specifications common to all steam locomotives... Specifications common to all steam locomotives. (a) Hand brakes. (1) Hand brakes will not be required on...) Locomotives having headlights which can not be safely and conveniently reached from pilot-beam or steam...

  9. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  10. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  11. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  12. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Specifications common to all steam locomotives... Specifications common to all steam locomotives. (a) Hand brakes. (1) Hand brakes will not be required on...) Locomotives having headlights which can not be safely and conveniently reached from pilot-beam or steam...

  13. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Specifications common to all steam locomotives... Specifications common to all steam locomotives. (a) Hand brakes. (1) Hand brakes will not be required on...) Locomotives having headlights which can not be safely and conveniently reached from pilot-beam or steam...

  14. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  15. 49 CFR 229.9 - Movement of non-complying locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... lite locomotive or a dead locomotive after the carrier has complied with the following: (1) A qualified... lite or dead within a yard, at speeds not in excess of 10 miles per hour, without meeting the... is responsible to insure that the movement may be safely made. (d) A dead locomotive may not...

  16. 40 CFR Appendix I to Part 92 - Emission Related Locomotive and Engine Parameters and Specifications

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Emission Related Locomotive and Engine Parameters and Specifications I Appendix I to Part 92 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Pt. 92, App. I Appendix I to...

  17. 49 CFR 240.105 - Criteria for selection of designated supervisors of locomotive engineers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of locomotive engineers. 240.105 Section 240.105 Transportation Other Regulations Relating to... CERTIFICATION OF LOCOMOTIVE ENGINEERS Component Elements of the Certification Process § 240.105 Criteria for selection of designated supervisors of locomotive engineers. (a) Each railroad's program shall...

  18. 49 CFR 240.105 - Criteria for selection of designated supervisors of locomotive engineers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... of locomotive engineers. 240.105 Section 240.105 Transportation Other Regulations Relating to... CERTIFICATION OF LOCOMOTIVE ENGINEERS Component Elements of the Certification Process § 240.105 Criteria for selection of designated supervisors of locomotive engineers. (a) Each railroad's program shall...

  19. 49 CFR 240.105 - Criteria for selection of designated supervisors of locomotive engineers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... of locomotive engineers. 240.105 Section 240.105 Transportation Other Regulations Relating to... CERTIFICATION OF LOCOMOTIVE ENGINEERS Component Elements of the Certification Process § 240.105 Criteria for selection of designated supervisors of locomotive engineers. (a) Each railroad's program shall...

  20. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  1. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  2. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  3. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  4. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  5. 49 CFR 1242.25 - Locomotive servicing facilities (account XX-19-27).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Locomotive servicing facilities (account XX-19-27... Structures § 1242.25 Locomotive servicing facilities (account XX-19-27). Separate common expenses according to distribution of common expenses in the following accounts: Locomotive Fuel (XX-51-67 and...

  6. Physiologic Responses to Motorized and Non-Motorized Locomotion Utilizing the International Space Station Treadmill

    NASA Technical Reports Server (NTRS)

    Smith, Cassie; Lee, Stuart MC; Laughlin, Mitzi; Loehr, James; Norcross, Jason; DeWitt, John; Hagan, R. D.

    2006-01-01

    Treadmill locomotion is used onboard the International Space Station (ISS) as a countermeasure to the effects of prolonged weightlessness. The treadmill operates in two modes: motorized (T-M) and non-motorized (T-NM). Little is known about the potential physiologic differences between modes which may affect countermeasure exercise prescription. PURPOSE: To quantify heart rate (HR), oxygen consumption (VO2), perceived exertion (RPE), and blood lactate (BLa) during T-M and T-NM locomotion at 2 and 4 mph in normal ambulatory subjects. METHODS: Twenty subjects (10 men, 10 women; 31+/-5 yr, 172+/-10 cm, 68+/-13 kg, mean SD) with a treadmill peakVO2 of 45.5+/-5.4 ml/kg/min (mean+/-SD) exercised on the ground-based ISS treadmill. Following a familiarization session in each mode, subjects completed two data collection sessions, T-M and T-NM in random order, at 2 and 4 mph. Subjects attempted to complete 5 min of exercise at each speed; if they could not maintain the speed, the trial was discontinued. At least 5 minutes of rest separated each speed trial, and at least 48 hrs separated each session. VO2 was measured continuously (metabolic gas analysis), while HR (HR monitor) and RPE (Borg Chart, 6-20 scale) were recorded each min. Not all subjects completed 5 min during each condition, therefore the mean of the min 3 and 4 was taken as representative of steady-state. BLa was measured (finger stick) within 2 min post-exercise. Paired t-tests were used to test for differences (p<0.05) between treadmill modes within the same speed. RESULTS: All twenty subjects completed at least 4 min of exercise during all conditions, except T-NM 4 mph when only 11 subjects completed the minimum exercise duration. VO2, HR, RPE and BLa were significantly higher during T-NM locomotion at both speeds.

  7. Locomotion, physical development, and brain myelination in rats treated with ionizing radiation in utero

    SciTech Connect

    Zaman, M.S.

    1989-01-01

    Effects of ionizing radiation on the emergence of locomotion skill and some physical development parameters were studied in laboratory rats (Fisher F-344 inbred strain). Rats were treated with 3 different doses of radiation (150 R, 15 R, and 6.8 R) delivered on the 20th day of the prenatal life. Results indicated that relatively moderate (15 R) to high (150 R) doses of radiation have effects on certain locomotion and physical development parameters. Exposure to 150 R affected pivoting, cliff-avoidance, upper jaw tooth eruption, body weight, and organs, such as brain, cerebral cortex, ovary, kidney, heart and spleen weights. Other parameters, such as negative geotaxis, eye opening, and lower jaw tooth eruption appeared to be affected in the 150 R treated animals. Exposure to 15 R affected pivoting and cliff-avoidance parameters. The cerebral cortex weight of the 15 R treated animals was found to be reduced at the age of day 30. Exposure to 6.8 R had no adverse effects on these parameters. Prenatal exposure to 150 R of radiation reduced the cerebral cortex weight by 22.07% at 30 days of age, and 20.15% at 52 days of age which caused a reduction in cerebral cortex myelin content by 20.16, and 22.89% at the ages of day 30 and day 52 respectively. Exposure to 150 R did not affect the myelin content of the cerebellum or the brain stem; or the myelin concentration (mg myelin/g brain tissue weight) of the cerebral cortex, cerebellum, and the brain stem. Exposure to 15 R, and 6.8 R did not affect either the myelin content or the myelin concentration of these brain areas.

  8. Energetic Extremes in Aquatic Locomotion by Coral Reef Fishes

    PubMed Central

    Fulton, Christopher J.; Johansen, Jacob L.; Steffensen, John F.

    2013-01-01

    Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s−1) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed. PMID:23326566

  9. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... requirements of 40 CFR part 1033. We have not changed production processes or quality-control procedures for... family by that installer. (f) An engine family is determined to have failed an audit, if at any time during the model year, you determine that the three locomotives audited are found to have had...

  10. Finite state model of locomotion for functional electrical stimulation systems.

    PubMed

    Popović, D B

    1993-01-01

    A finite state model of locomotion was developed to simplify a controller design for motor activities of handicapped humans. This paper presents a model developed for real time control of locomotion with functional electrical stimulation (FES) assistive systems. Hierarchical control of locomotion was adopted with three levels: voluntary, coordination and actuator level. This paper deals only with coordination level of control. In our previous studies we demonstrated that a skill-based expert system can be used for coordination level of control in multi-joint FES systems. Basic elements in this skill-based expert system are production rules. Production rules have the form of If-Then conditional expressions. A technique of automatic determination of these conditional expressions is presented in this paper. This technique for automatic synthesis of production rules uses fuzzy logic and artificial neural networks (ANN). The special class of fuzzy logic elements used in this research is called preferential neurons. The preferential neurons were used to estimate the relevance of each of the sensory inputs to the recognition of patterns defined as finite states. The combination of preferential neurons forms a preferential neural network. The preferential neural network belongs to a class of ANNs. The preferential neural network determined the set of finite states convenient for a skill-based expert system for different modalities of locomotion. PMID:8234764

  11. Drosophila melanogaster (fruit fly) locomotion during a sounding rocket flight

    NASA Astrophysics Data System (ADS)

    Miller, Mark S.; Keller, Tony S.

    2008-05-01

    The locomotor activity of young Drosophila melanogaster (fruit fly) was studied during a Nike-Orion sounding rocket flight, which included a short-duration microgravity exposure. An infrared monitoring system was used to determine the activity level, instantaneous velocity, and continuous velocity of 240 (120 male, 120 female) fruit flies. Individual flies were placed in chambers that limit their motion to walking. Chambers were oriented both vertically and horizontally with respect to the rocket's longitudinal axis. Significant changes in Drosophila locomotion patterns were observed throughout the sounding rocket flight, including launch, microgravity exposure, payload re-entry, and after ocean impact. During the microgravity portion of the flight (3.8 min), large increases in all locomotion measurements for both sexes were observed, with some measurements doubling compared to pad (1 G) data. Initial effects of microgravity were probably delayed due to large accelerations from the payload despining immediately before entering microgravity. The results indicate that short-duration microgravity exposure has a large effect on locomotor activity for both males and females, at least for a short period of time. The locomotion increases may explain the increased male aging observed during long-duration exposure to microgravity. Studies focusing on long-duration microgravity exposure are needed to confirm these findings, and the relationship of increased aging and locomotion.

  12. 49 CFR 223.11 - Requirements for existing locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of the Secretary of Transportation, 49 CFR 1.49(m)) ... 49 Transportation 4 2010-10-01 2010-10-01 false Requirements for existing locomotives. 223.11 Section 223.11 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL...

  13. Fish locomotion: insights from both simple and complex mechanical models

    NASA Astrophysics Data System (ADS)

    Lauder, George

    2015-11-01

    Fishes are well-known for their ability to swim and maneuver effectively in the water, and recent years have seen great progress in understanding the hydrodynamics of aquatic locomotion. But studying freely-swimming fishes is challenging due to difficulties in controlling fish behavior. Mechanical models of aquatic locomotion have many advantages over studying live animals, including the ability to manipulate and control individual structural or kinematic factors, easier measurement of forces and torques, and the ability to abstract complex animal designs into simpler components. Such simplifications, while not without their drawbacks, facilitate interpretation of how individual traits alter swimming performance and the discovery of underlying physical principles. In this presentation I will discuss the use of a variety of mechanical models for fish locomotion, ranging from simple flexing panels to complex biomimetic designs incorporating flexible, actively moved, fin rays on multiple fins. Mechanical devices have provided great insight into the dynamics of aquatic propulsion and, integrated with studies of locomotion in freely-swimming fishes, provide new insights into how fishes move through the water.

  14. 4. 'OLD NUMBER SIX' STEAM LOCOMOTIVE USED BY SEATTLE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. 'OLD NUMBER SIX' -- STEAM LOCOMOTIVE USED BY SEATTLE CITY LIGHT ON THEIR RAILROAD FROM MARBLEMOUNT TO DIABLE AND NOW A POPULAR TOURIST ATTRACTION IN NEWHALEM, 1989. - Skagit Power Development, Skagit River & Newhalem Creek Hydroelectric Project, On Skagit River, Newhalem, Whatcom County, WA

  15. Ontogeny of locomotion in mountain gorillas and chimpanzees.

    PubMed

    Doran, D M

    1997-04-01

    The African apes are a group of closely related taxa that differ considerably in body size. In spite of the large body size difference, the African apes are similar in many aspects of their morphology; it has been suggested that most of their differences result from selection for these body size differences (Shea, 1988). The influence of body size on locomotion has been well-documented, but what is less clear, is whether these behavioral differences occur throughout ontogeny because few studies have directly addressed the influence of ontogeny (and changing body size) on locomotion. This study documents the ontogeny of mountain gorilla locomotion and compares it with that of chimpanzees in order to consider how changing body size during ontogeny influences locomotion in the two species. Results indicate that gorilla locomotor development is greatly accelerated compared with chimpanzees, and that much of the interspecific variation in age can be explained by body size. When chimpanzees and gorillas are at similar sizes (although widely disparate ages), they perform very similar locomotor activities. However, it is incorrect to view a gorilla as a faster growing and ultimately larger chimpanzee. Throughout ontogeny, gorillas have broader scapulae and relatively shorter phalanges and metacarpals than chimpanzees (Susman, 1979; Shea, 1981; Jungers & Susman, 1984; Inouye, 1992) which are associated differences in mountain gorilla and chimpanzee suspensory behavior; gorillas never show as high an incidence of suspensory behavior as chimpanzees during ontogeny. PMID:9085185

  16. Current problems: New similiquid lubricant for locomotive gears

    SciTech Connect

    Shibryaev, S.B.; Nesterov, A.V.; Seregina, I.E.

    1995-01-01

    The development of a formula for a new, domestically manufactured, semiliquid lubricant is described. The lubricant is for traction gears of locomotives and motorized cars of multiple-unit trains that will ensure year-round operation. Scientific principles have been used in selecting additives and in increasing the effectiveness of the additives by means of oxygen-containing synthetic oils.

  17. 21st Century Locomotive Technology: Quarterly Technical Status Report 28

    SciTech Connect

    Lembit Salasoo; Ramu Chandra

    2010-02-19

    Thermal testing of a subscale locomotive sodium battery module was initiated.to validate thermal models. The hybrid trip optimizer problem was formulated. As outcomes of this project, GE has proceeded to commercialize trip optimizer technology, and has initiated work on a state-of-the-art battery manufacturing plant for high energy density, sodium-based batteries.

  18. Gaze Stabilization During Locomotion Requires Full Body Coordination

    NASA Technical Reports Server (NTRS)

    Mulavara, A. P.; Miller, C. A.; Houser, J.; Richards, J. T.; Bloomberg, J. J.

    2001-01-01

    Maintaining gaze stabilization during locomotion places substantial demands on multiple sensorimotor subsystems for precise coordination. Gaze stabilization during locomotion requires eye-head-trunk coordination (Bloomberg, et al., 1997) as well as the regulation of energy flow or shock-wave transmission through the body at high impact phases with the support surface (McDonald, et al., 1997). Allowing these excessive transmissions of energy to reach the head may compromise gaze stability. Impairments in these mechanisms may lead to the oscillopsia and decreased dynamic visual acuity seen in crewmembers returning from short and long duration spaceflight, as well as in patients with vestibular disorders (Hillman, et al., 1999). Thus, we hypothesize that stabilized gaze during locomotion results from full-body coordination of the eye-head-trunk system combined with the lower limb apparatus. The goal of this study was to determine how multiple, interdependent full- body sensorimotor subsystems aiding gaze stabilization during locomotion are functionally coordinated, and how they adaptively respond to spaceffight.

  19. Locomotion pattern and trunk musculoskeletal architecture among Urodela

    PubMed Central

    Omura, Ayano; Ejima, Ken-Ichiro; Honda, Kazuya; Anzai, Wataru; Taguchi, Yuki; Koyabu, Daisuke; Endo, Hideki

    2015-01-01

    We comparatively examined the trunk musculature and prezygapophyseal angle of mid-trunk vertebra in eight urodele species with different locomotive modes (aquatic Siren intermedia, Amphiuma tridactylum, Necturus maculosus and Andrias japonicus; semi-aquatic Cynops pyrrhogaster, Cynops ensicauda; and terrestrial Hynobius nigrescens, Hynobius lichenatus and Ambystoma tigrinum). We found that the more terrestrial species were characterized by larger dorsal and abdominal muscle weight ratios compared with those of the more aquatic species, whereas muscle ratios of the lateral hypaxial musculature were larger in the more aquatic species. The lateral hypaxial muscles were thicker in the more aquatic species, whereas the M. rectus abdominis was more differentiated in the more terrestrial species. Our results suggest that larger lateral hypaxial muscles function for lateral bending during underwater locomotion in aquatic species. Larger dorsalis and abdominal muscles facilitate resistance against sagittal extension of the trunk, stabilization and support of the ventral contour line against gravity in terrestrial species. The more aquatic species possessed a more horizontal prezygapophyseal angle for more flexible lateral locomotion. In contrast, the more terrestrial species have an increasingly vertical prezygapophyseal angle to provide stronger column support against gravity. Thus, we conclude trunk structure in urodeles differs clearly according to their locomotive modes. PMID:25914411

  20. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion II

    ERIC Educational Resources Information Center

    Lee, Scott

    2015-01-01

    In the second paper of this series, the effect of transverse femoral stresses due to locomotion in theropod dinosaurs of different sizes was examined for the case of an unchanging leg geometry. Students are invariably thrilled to learn about theropod dinosaurs, and this activity applies the concepts of torque and stress to the issue of theropod…

  1. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion

    ERIC Educational Resources Information Center

    Lee, Scott

    2015-01-01

    In our first article on scaling in theropod dinosaurs, the longitudinal stress in the leg bones due to supporting the weight of the animal was studied and found not to control the dimensions of the femur. As a continuation of our study of elasticity in dinosaur bones, we now examine the transverse stress in the femur due to locomotion and find…

  2. 29 CFR 1910.180 - Crawler locomotive and truck cranes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Crawler locomotive and truck cranes. 1910.180 Section 1910.180 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Materials Handling and Storage §...

  3. Kinematics of treadmill versus overground locomotion in horses.

    PubMed

    Buchner, H H; Savelberg, H H; Schamhardt, H C; Merkens, H W; Barneveld, A

    1994-05-01

    A kinematic analysis was carried out to compare treadmill and overground locomotion in horses at the trot. Stride variables and limb and trunk movements of 10 Dutch Warmblood horses were measured using the CODA-3 gait analysis system. Overground recordings were made on a rubber ground surface and on an asphalt track. Treadmill recordings were taken after a controlled habituation programme and at the same velocities as measured overground. On asphalt, a shorthened stride duration and a decreased vertical displacement of the withers were found compared with those on rubber ground. On the treadmill, stance duration of the forelimbs was longer than for either overground condition. Correspondingly, the hind limbs were placed earlier than the forelimbs in making diagonal ground contact in overground locomotion, but this changed to preceding forelimbs on the treadmill. Both forelimbs and hind limbs were moved more caudally during the retraction phase on the treadmill, while no differences were found in the protraction angle. The vertical movement of the hooves as well as the withers was smaller on the treadmill than on rubber ground. Treadmill belt velocity decreased by 9% during the stance phase. This is supposed to be an important reason for the differences in biomechanics and kinematics between treadmill and overground locomotion, which must be kept in mind when data obtained during treadmill locomotion have to be extrapolated to overground conditions. PMID:7801509

  4. Transmembrane channel-like (tmc) gene regulates Drosophila larval locomotion.

    PubMed

    Guo, Yanmeng; Wang, Yuping; Zhang, Wei; Meltzer, Shan; Zanini, Damiano; Yu, Yue; Li, Jiefu; Cheng, Tong; Guo, Zhenhao; Wang, Qingxiu; Jacobs, Julie S; Sharma, Yashoda; Eberl, Daniel F; Göpfert, Martin C; Jan, Lily Yeh; Jan, Yuh Nung; Wang, Zuoren

    2016-06-28

    Drosophila larval locomotion, which entails rhythmic body contractions, is controlled by sensory feedback from proprioceptors. The molecular mechanisms mediating this feedback are little understood. By using genetic knock-in and immunostaining, we found that the Drosophila melanogaster transmembrane channel-like (tmc) gene is expressed in the larval class I and class II dendritic arborization (da) neurons and bipolar dendrite (bd) neurons, both of which are known to provide sensory feedback for larval locomotion. Larvae with knockdown or loss of tmc function displayed reduced crawling speeds, increased head cast frequencies, and enhanced backward locomotion. Expressing Drosophila TMC or mammalian TMC1 and/or TMC2 in the tmc-positive neurons rescued these mutant phenotypes. Bending of the larval body activated the tmc-positive neurons, and in tmc mutants this bending response was impaired. This implicates TMC's roles in Drosophila proprioception and the sensory control of larval locomotion. It also provides evidence for a functional conservation between Drosophila and mammalian TMCs. PMID:27298354

  5. Online measurement for geometrical parameters of locomotive wheel set

    NASA Astrophysics Data System (ADS)

    Wu, Kaihua; Li, Zhengjie; Ban, Tao

    2009-11-01

    Locomotive is the most important parts of a train. Wheel set is the major running components of a locomotive. Wheel set tread is the contacting part with the rail and tread will be worn down gradually. The wearing degree of the wheel set tread is one of the main factors that influence the safety and stability of running train. The measurement of wheel set wear is usually static and by handwork, which limits the accuracy and reliability. An automatic measurement method for geometrical parameters of locomotive wheel set based on optoelectronic technique was proposed. Geometrical parameters include flange thickness, flange height and rim inside distance. Linear structured laser light was projected on the wheel tread surface. The geometrical parameters can be deduced from the profile image. An online image acquisition system was designed based on asynchronous reset of CCD. Precision hardware time-delay and asynchronous reset pulse generation circuits were designed. The entire time sequence of asynchronous reset was researched. Images were acquired only when wheel sets moved into the designed position. The image acquisition was fulfilled by hardware interrupt mode. The measuring system was installed along the straight railway section. When the locomotive was running in a limited speed, the devices placed alone railway line can measure the geometrical parameters automatically.

  6. 13. VIEW OF RAILROAD EXHIBIT AT EL PORTAL. SHAY LOCOMOTIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. VIEW OF RAILROAD EXHIBIT AT EL PORTAL. SHAY LOCOMOTIVE IS FROM THE HETCH HETCHY RAILROAD. CABOOSE IS FROM THE YOSEMITE VALLEY RAILROAD. FOREST ROAD IN FOREGROUND IS THE ALIGNMENT OF THE YOSEMITE VALLEY RAILROAD. LOOKING W. GIS: N-37 40 27.0 / W-119 47 10.5 - Yosemite National Park Roads & Bridges, Yosemite Village, Mariposa County, CA

  7. Effect of rubber flooring on cow locomotion and gene expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to evaluate the effect of 2 dairy cow housing systems on cow locomotion and expression of genes associated with lameness, during the dry and peri-parturient period. Cows were assigned to free-stall housing with either rubber (RUB; n=13) or concrete (CON; n=14) at the feed-f...

  8. Kinematic Differences Between Motorized and Nonmotorized Treadmill Locomotion

    NASA Technical Reports Server (NTRS)

    DeWitt, John K.; Bentley, Jason R.; Lee, Stuart M. C.; Norcross, Jason; Smith, Cassie; Hagan, R. Donald

    2006-01-01

    There are few scientific publications comparing human locomotion between motorized and nonmotorized treadmills. Lakomy (1987) and Gamble et al (1988) reported that forward lean is greater on a nonmotorized treadmill to aid in the generation of horizontal force necessary for belt propulsion, but there are no data concerning lower limb kinematics. During long-term spaceflight, astronauts use locomotive exercise to mitigate the physiological effects caused by long-term exposure to microgravity. A critical decision for mission planners concerns the requirements for a treadmill to be used during potential trips to the Moon and Mars. Treadmill operation in an un-powered configuration could reduce mission resource demands, but also may impact the efficacy of treadmill exercise countermeasures. To ascertain the most appropriate type of treadmill to be used, it is important to understand biomechanical differences between motorized (M) and nonmotorized (NM) locomotion. The purpose of this evaluation was to test for differences in lower limb kinematics that occur during M and NM treadmill locomotion at two speeds. It was hypothesized that hip and knee joint angle trajectories would differ between the conditions.

  9. Human locomotion and workload for simulated lunar and Martian environments.

    PubMed

    Newman, D J; Alexander, H L

    1993-08-01

    Human locomotion in simulated lunar and Martian environments is investigated. A unique human-rated underwater treadmill and an adjustable ballasting harness simulate partial gravity in order to better understand how gravity determines the biomechanics and energetics of human locomotion. This study has two research aspects, biomechanics and energetics. The fundamental biomechanics measurements are continuously recorded vertical forces as exerted by subjects of the treadmill which is instrumented with a force platform. Experimental results indicate that peak vertical force and stride frequency decrease as the gravity level is reduced. Foot contact time is independent of gravity level. Oxygen uptake measurements, VO2, constitute the energetics, or workload, data for this study. As theory predicts, locomotion energy requirements for lunar (1/6-g) and Martian (3/8-g) gravity levels are significantly less than at 1-g. The observed variation in workload with gravity level is nonmonotonic, however, in over half the subject population. The hypothesis is offered that energy expenditure increases for lunar, as compared with Martian, locomotion due to the subject "wasting energy" for stability and posture control in simulated lunar gravity. Biomechanics data could influence advanced spacesuit design and planetary habitat design, while workload data will help define oxygen requirements for planetary life support systems. PMID:11541642

  10. 30 CFR 77.1603 - Trains and locomotives; authorized persons.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Trains and locomotives; authorized persons. 77.1603 Section 77.1603 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Loading and Haulage...

  11. 30 CFR 77.1603 - Trains and locomotives; authorized persons.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Trains and locomotives; authorized persons. 77.1603 Section 77.1603 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Loading and Haulage...

  12. 30 CFR 77.1603 - Trains and locomotives; authorized persons.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Trains and locomotives; authorized persons. 77.1603 Section 77.1603 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Loading and Haulage...

  13. 30 CFR 77.1603 - Trains and locomotives; authorized persons.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Trains and locomotives; authorized persons. 77.1603 Section 77.1603 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Loading and Haulage...

  14. 30 CFR 77.1603 - Trains and locomotives; authorized persons.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Trains and locomotives; authorized persons. 77.1603 Section 77.1603 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Loading and Haulage...

  15. Analysis of locomotion scores with altered periparturient management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate locomotion scoring as a predictor of lameness in heifers and multiparous cows subjected to periparurient management change. Heifers were either milked 3 wk prior to expected calving or not milked until after calving. The multiparous cows were fed hyper-a...

  16. Using Computational and Mechanical Models to Study Animal Locomotion

    PubMed Central

    Miller, Laura A.; Goldman, Daniel I.; Hedrick, Tyson L.; Tytell, Eric D.; Wang, Z. Jane; Yen, Jeannette; Alben, Silas

    2012-01-01

    Recent advances in computational methods have made realistic large-scale simulations of animal locomotion possible. This has resulted in numerous mathematical and computational studies of animal movement through fluids and over substrates with the purpose of better understanding organisms’ performance and improving the design of vehicles moving through air and water and on land. This work has also motivated the development of improved numerical methods and modeling techniques for animal locomotion that is characterized by the interactions of fluids, substrates, and structures. Despite the large body of recent work in this area, the application of mathematical and numerical methods to improve our understanding of organisms in the context of their environment and physiology has remained relatively unexplored. Nature has evolved a wide variety of fascinating mechanisms of locomotion that exploit the properties of complex materials and fluids, but only recently are the mathematical, computational, and robotic tools available to rigorously compare the relative advantages and disadvantages of different methods of locomotion in variable environments. Similarly, advances in computational physiology have only recently allowed investigators to explore how changes at the molecular, cellular, and tissue levels might lead to changes in performance at the organismal level. In this article, we highlight recent examples of how computational, mathematical, and experimental tools can be combined to ultimately answer the questions posed in one of the grand challenges in organismal biology: “Integrating living and physical systems.” PMID:22988026

  17. Energetic extremes in aquatic locomotion by coral reef fishes.

    PubMed

    Fulton, Christopher J; Johansen, Jacob L; Steffensen, John F

    2013-01-01

    Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s(-1)) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed. PMID:23326566

  18. 1. RESTORED GLOVER LOCOMOTIVE #81421 JUST WEST OF MARIETTA SQUARE; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. RESTORED GLOVER LOCOMOTIVE #81421 JUST WEST OF MARIETTA SQUARE; 36 INCH GAUGE 2-6-0, BUILT 1-3-17. RETURNED FOR REPAIR AND RESALE IN 1923, LAST OFFERED FOR SALE IN 1931 FOR $750. - Glover Machine Works, 651 Butler Street, Marietta, Cobb County, GA

  19. Locomotive Crane placing concrete on trestle at coal dock (Pier ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Locomotive Crane placing concrete on trestle at coal dock (Pier 01) - looking southeast. Taken Jan 4, 1924. 14th Naval District Photo Collection Item No. 4872-B - U.S. Naval Base, Pearl Harbor, Exterior Cranes, Waterfront Crane Track System, Pearl City, Honolulu County, HI

  20. 3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR SURFACE HAULAGE OF MINE CARS, LOOKING SOUTHWEST; NOTE GEARING - Nuttallburg Mine Complex, Main Mine, North side of New River, 2.7 miles upstream from Fayette Landing, Lookout, Fayette County, WV

  1. 6. VIEW OF BORING MILL. Chuck action of locomotive wheel ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW OF BORING MILL. Chuck action of locomotive wheel Wheel weight 1200 pounds, 3'-0' diameter. Table 53' in diameter Wheel is 48'. Largest hole that can be bored is 9-1/2' plus (GE axle is 10'). - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  2. Zero-Gravity Locomotion Simulators: New Ground-Based Analogs for Microgravity Exercise Simulation

    NASA Technical Reports Server (NTRS)

    Perusek, Gail P.; DeWitt, John K.; Cavanagh, Peter R.; Grodsinsky, Carlos M.; Gilkey, Kelly M.

    2007-01-01

    pneumatic subject load device to apply a near constant gravity-replacement load to the test subject during exercise, and is currently used in conjunction with the General Clinical Research Center for evaluating exercise protocols using a bedrest analog. The enhanced ZLS (eZLS) at NASA Glenn Research Center features an offloaded treadmill that floats on a thin film of air and interfaces to a force reaction frame via variably-compliant isolators, or vibration isolation system. The isolators can be configured to simulate compliant interfaces to the vehicle, which affects mechanical loading to crewmembers during exercise, and has been used to validate system dynamic models for new countermeasures equipment designs, such as the second International Space Station treadmill slated for use in 2010. In the eZLS, the test subject and exercise device can be pitched at the appropriate angle for partial gravity simulations, such as lunar gravity (1/6th earth gravity). On both the eZLS and the NASA-Johnson Space Center standalone ZLS installed at the University of Texas Medical Branch in Galveston, Texas, USA, the subject's body weight relative to the treadmill is controlled via a linear motor subject load device (LM-SLD). The LM-SLD employs a force-feedback closed-loop control system to provide a relatively constant force to the test subject during locomotion, and is set and verified for subject safety prior to each session. Locomotion data were collected during parabolic flight and on the eZLS. The purpose was to determine the similarities and differences between locomotion in actual and simulated microgravity. Subjects attained greater amounts of hip flexion during walking and running during parabolic flight. During running, subjects had greater hip range of motion. Trunk motion was significantly less on the eZLS than during parabolic flight. Peak impact forces, loading rate, and impulse were greater on the eZLS than during parabolic while walking with a low external load (EL) and

  3. Simulations of Unsteady Aquatic Locomotion: From Unsteadiness in Straight-Line Swimming to Fast-Starts.

    PubMed

    Borazjani, Iman

    2015-10-01

    Unsteady aquatic locomotion is not an exception, but rather how animals often swim. It includes fast-starts (C-start or S-start), escape maneuvers, turns, acceleration/deceleration, and even during steady locomotion the swimming speed fluctuates, i.e., there is unsteadiness. Here, a review of the recent work on unsteady aquatic locomotion with emphasis on numerical simulations is presented. The review is started by an overview of different theoretical and numerical methods that have been used for unsteady swimming, and then the insights provided by these methods on (1) unsteadiness in straight-line swimming and (2) unsteady fast-starts and turns are discussed. The swimming speed's unsteady fluctuations during straight-line swimming are typically less than 3% of the average swimming speed, but recent simulations show that body shape affects fluctuations more than does body kinematics, i.e., changing the shape of the body generates larger fluctuations than does changing its kinematics. For fast-starts, recent simulations show that the best motion to maximize the distance traveled from rest are similar to the experimentally observed C-start maneuvers. Furthermore, another set of simulations, which are validated against measurements of flow in experiments with live fish, investigate the role of fins during the C-start. The simulations showed that most of the force is generated by the body of the fish (not by fins) during the first stage of the C-start when the fish bends itself into the C-shape. However, in the second stage, when it rapidly bends out of the C-shape, more than 70% of the instantaneous hydrodynamic force is produced by the tail. The effect of dorsal and anal fins was less than 5% of the instantaneous force in both stages, except for a short period of time (2 ms) just before the second stage. Therefore, the active control and the erection of the anal/dorsal fins might be related to retaining the stability of the sunfish against roll and pitch during the C

  4. Bird terrestrial locomotion as revealed by 3D kinematics.

    PubMed

    Abourachid, Anick; Hackert, Remi; Herbin, Marc; Libourel, Paul A; Lambert, François; Gioanni, Henri; Provini, Pauline; Blazevic, Pierre; Hugel, Vincent

    2011-12-01

    Most birds use at least two modes of locomotion: flying and walking (terrestrial locomotion). Whereas the wings and tail are used for flying, the legs are mainly used for walking. The role of other body segments remains, however, poorly understood. In this study, we examine the kinematics of the head, the trunk, and the legs during terrestrial locomotion in the quail (Coturnix coturnix). Despite the trunk representing about 70% of the total body mass, its function in locomotion has received little scientific interest to date. This prompted us to focus on its role in terrestrial locomotion. We used high-speed video fluoroscopic recordings of quails walking at voluntary speeds on a trackway. Dorso-ventral and lateral views of the motion of the skeletal elements were recorded successively and reconstructed in three dimensions using a novel method based on the temporal synchronisation of both views. An analysis of the trajectories of the body parts and their coordination showed that the trunk plays an important role during walking. Moreover, two sub-systems participate in the gait kinematics: (i) the integrated 3D motion of the trunk and thighs allows for the adjustment of the path of the centre of mass; (ii) the motion of distal limbs transforms the alternating forward motion of the feet into a continuous forward motion at the knee and thus assures propulsion. Finally, head bobbing appears qualitatively synchronised to the movements of the trunk. An important role for the thigh muscles in generating the 3D motion of the trunk is suggested by an analysis of the pelvic anatomy. PMID:21982408

  5. Arachnoid cyst spontaneous rupture.

    PubMed

    Marques, Inês Brás; Vieira Barbosa, José

    2014-01-01

    Arachnoid cysts are benign congenital cerebrospinal fluid collections, usually asymptomatic and diagnosed incidentally in children or adolescents. They may become symptomatic after enlargement or complications, frequently presenting with symptoms of intracranial hypertension. We report an unusual case of progressive refractory headache in an adult patient due to an arachnoid cyst spontaneous rupture. Although clinical improvement occurred with conservative treatment, the subdural hygroma progressively enlarged and surgical treatment was ultimately needed. Spontaneous rupture is a very rare complication of arachnoid cysts. Accumulation of cerebrospinal fluid accumulation in the subdural space causes sustained intracranial hypertension that may be life-threatening and frequently requires surgical treatment. Patients with arachnoid cysts must be informed on their small vulnerability to cyst rupture and be aware that a sudden and severe headache, especially if starting after minor trauma or a Valsalva manoeuvre, always requires medical evaluation. PMID:24581205

  6. Spontaneous Quantum Hall Liquids

    NASA Astrophysics Data System (ADS)

    Zhang, Fan

    2012-02-01

    Driven by electron-electron interactions, bilayer graphene and its thicker cousins, chirally (ABC) stacked multilayers, exhibit a variety of distinct broken symmetry states in which each spin-valley flavor spontaneously transfers charge between layers, because of their flat touching bands and large pseudospin chiralities. These gapped states are accompanied by large momentum space Berry curvatures and different types of topological orders. These competing ground states are distinguished by their flavor Hall conductivities, orbital magnetizations, edge state properties, and response to external fields. These spontaneous quantum Hall (SQH) states at zero field smoothly evolve into quantum Hall ferromagnet states at finite field. Various phase transitions occur by tuning carrier densities, temperature, and external fields. Recently, SQH states have started to be observed and explored in transport and Hall experiments on suspended devices with dual gates.

  7. Spontaneous Perforation of Pyometra.

    PubMed

    Sharma, Nalini; Singh, Ahanthem Santa; Bhaphiralyne, Wankhar

    2016-04-01

    Pyometra is collection of purulent material which occurs when there is interference with its normal drainage. It is an uncommon condition with incidence of 0.1 to 0.5% of all gynecological patients. Spontaneous rupture of uterus is an extremely rare complication of pyometra. A 65-year-old lady presented with pain abdomen and purulent vaginal discharge. Preoperative diagnosis of pyometra was made by magnetic resonance imaging (MRI). Laparotomy followed by peritoneal lavage and repair of perforation was performed. Although spontaneously perforated pyometra is rare, the condition must be borne in mind with regard to elderly women with acute abdominal pain. Preoperative diagnosis of perforated pyometra is absolutely essential. Computed tomography (CT) and MRI are diagnostic tools. In selected cases conservative approach at surgery can be opted. PMID:27152313

  8. Spontaneous Perforation of Pyometra

    PubMed Central

    Singh, Ahanthem Santa; Bhaphiralyne, Wankhar

    2016-01-01

    Pyometra is collection of purulent material which occurs when there is interference with its normal drainage. It is an uncommon condition with incidence of 0.1 to 0.5% of all gynecological patients. Spontaneous rupture of uterus is an extremely rare complication of pyometra. A 65-year-old lady presented with pain abdomen and purulent vaginal discharge. Preoperative diagnosis of pyometra was made by magnetic resonance imaging (MRI). Laparotomy followed by peritoneal lavage and repair of perforation was performed. Although spontaneously perforated pyometra is rare, the condition must be borne in mind with regard to elderly women with acute abdominal pain. Preoperative diagnosis of perforated pyometra is absolutely essential. Computed tomography (CT) and MRI are diagnostic tools. In selected cases conservative approach at surgery can be opted. PMID:27152313

  9. Spontaneous ileostomy closure

    PubMed Central

    Alyami, Mohammad S.; Lundberg, Peter W.; Cotte, Eddy G.; Glehen, Olivier J.

    2016-01-01

    Iatrogenic ileostomies are routinely placed during colorectal surgery for the diversion of intestinal contents to permit healing of the distal anastomosis prior to elective reversal. We present an interesting case of spontaneous closure of a diverting ileostomy without any adverse effects to the patient. A 65-year-old woman, positive for hereditary non-polyposis colorectal cancer type-I, with locally invasive cancer of the distal colon underwent en-bloc total colectomy, hysterectomy, and bilateral salpingoophorectomy with creation of a proximal loop ileostomy. The ostomy temporarily closed without reoperation at 10 weeks, after spontaneously reopening, it definitively closed, again without surgical intervention at 18 weeks following the original surgery. This rare phenomenon has occurred following variable colorectal pathology and is poorly understood, particularly in patients with aggressive disease and adjunct perioperative interventions. PMID:27279518

  10. [Spontaneous intraperitoneal hemorrhage: etiology].

    PubMed

    Ksontini, R; Roulet, D; Cosendey, B A; Cavin, R

    2001-10-01

    Spontaneous intraperitoneal hemorrhage is a rare and sometime fatal condition. The clinical presentation may range from a non-specific abdominal pain to an acute abdomen with hemodynamic instability. Often, a preoperative diagnosis cannot be obtained. Immediate surgical exploration remains the treatment of choice. However, pre or postoperative diagnosis can sometime be confirmed and treated with interventional radiology. In rare cases, the site of bleeding remains unknown despite intraoperative exploration and radiographic studies. PMID:11715286

  11. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  12. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  13. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  14. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  15. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  16. A Locomotion Intent Prediction System Based on Multi-Sensor Fusion

    PubMed Central

    Chen, Baojun; Zheng, Enhao; Wang, Qining

    2014-01-01

    Locomotion intent prediction is essential for the control of powered lower-limb prostheses to realize smooth locomotion transitions. In this research, we develop a multi-sensor fusion based locomotion intent prediction system, which can recognize current locomotion mode and detect locomotion transitions in advance. Seven able-bodied subjects were recruited for this research. Signals from two foot pressure insoles and three inertial measurement units (one on the thigh, one on the shank and the other on the foot) are measured. A two-level recognition strategy is used for the recognition with linear discriminate classifier. Six kinds of locomotion modes and ten kinds of locomotion transitions are tested in this study. Recognition accuracy during steady locomotion periods (i.e., no locomotion transitions) is 99.71% ± 0.05% for seven able-bodied subjects. During locomotion transition periods, all the transitions are correctly detected and most of them can be detected before transiting to new locomotion modes. No significant deterioration in recognition performance is observed in the following five hours after the system is trained, and small number of experiment trials are required to train reliable classifiers. PMID:25014097

  17. Influence of person- and situation-specific characteristics on collision avoidance behavior in human locomotion.

    PubMed

    Knorr, Alexander G; Willacker, Lina; Hermsdörfer, Joachim; Glasauer, Stefan; Krüger, Melanie

    2016-09-01

    In everyday situations, pedestrians deploy successful strategies to avoid collisions with other persons crossing their paths. In this study, 2 experiments were conducted to investigate to what extent personal or situational characteristics affect role attribution and contribution to successful collision avoidance in human locomotion. Pairs of subjects walked at their natural speed from a start to a goal point. Walking paths were defined in such a way that subjects would collide halfway on their trajectory, if they did not actively avoid colliding by speed or path adjustments. In the first experiment, we investigated whether crossing order, path, and speed adjustments correlate with subject-specific parameters, such as gender, height, and personality traits. It is interesting that individuals' collision avoidance behavior was not correlated with any of these factors. In the second experiment, initial walking speed and heading were used to predict the crossing order. It was found that these 2 parameters are sufficient to estimate future role attribution with 95% confidence already 2.5 m before the crossing; that is, even before any collision avoidance behavior is initiated. In sum, this suggests that collision avoidance strategies in human locomotion are based on situational rather than on personal characteristics. These situational characteristics result in role attributions, which are highly predictable within and across pairs of pedestrians, whereby the role-dependent contribution of the pedestrian giving way is of greater relevance for successful collision avoidance. (PsycINFO Database Record PMID:26999273

  18. A dynamical systems analysis of afferent control in a neuromechanical model of locomotion. I. Rhythm generation

    PubMed Central

    Spardy, Lucy E.; Markin, Sergey N.; Shevtsova, Natalia A.; Prilutsky, Boris I.; Rybak, Ilya A.; Rubin, Jonathan E.

    2012-01-01

    Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical systems methods, in a series of two papers, we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed and open loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback and to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structure in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury. PMID:22058274

  19. A dynamical systems analysis of afferent control in a neuromechanical model of locomotion: I. Rhythm generation.

    PubMed

    Spardy, Lucy E; Markin, Sergey N; Shevtsova, Natalia A; Prilutsky, Boris I; Rybak, Ilya A; Rubin, Jonathan E

    2011-12-01

    Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical system methods, in a series of two papers we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed- and open-loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback, and then to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structures in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury. PMID:22058274

  20. Dynamics of underwater legged locomotion: modeling and experiments on an octopus-inspired robot.

    PubMed

    Calisti, M; Corucci, F; Arienti, A; Laschi, C

    2015-08-01

    This paper studies underwater legged locomotion (ULL) by means of a robotic octopus-inspired prototype and its associated model. Two different types of propulsive actions are embedded into the robot model: reaction forces due to leg contact with the ground and hydrodynamic forces such as the drag arising from the sculling motion of the legs. Dynamic parameters of the model are estimated by means of evolutionary techniques and subsequently the model is exploited to highlight some distinctive features of ULL. Specifically, the separation between the center of buoyancy (CoB)/center of mass and density affect the stability and speed of the robot, whereas the sculling movements contribute to propelling the robot even when its legs are detached from the ground. The relevance of these effects is demonstrated through robotic experiments and model simulations; moreover, by slightly changing the position of the CoB in the presence of the same feed-forward activation, a number of different behaviors (i.e. forward and backward locomotion at different speeds) are achieved. PMID:26226238

  1. A dynamical systems analysis of afferent control in a neuromechanical model of locomotion: I. Rhythm generation

    NASA Astrophysics Data System (ADS)

    Spardy, Lucy E.; Markin, Sergey N.; Shevtsova, Natalia A.; Prilutsky, Boris I.; Rybak, Ilya A.; Rubin, Jonathan E.

    2011-10-01

    Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical system methods, in a series of two papers we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed- and open-loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback, and then to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structures in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury.

  2. Self-regulatory mode (locomotion and assessment), well-being (subjective and psychological), and exercise behavior (frequency and intensity) in relation to high school pupils' academic achievement.

    PubMed

    Garcia, Danilo; Jimmefors, Alexander; Mousavi, Fariba; Adrianson, Lillemor; Rosenberg, Patricia; Archer, Trevor

    2015-01-01

    Background. Self-regulation is the procedure implemented by an individual striving to reach a goal and consists of two inter-related strategies: assessment and locomotion. Moreover, both subjective and psychological well-being along exercise behaviour might also play a role on adolescents academic achievement. Method. Participants were 160 Swedish high school pupils (111 boys and 49 girls) with an age mean of 17.74 (sd = 1.29). We used the Regulatory Mode Questionnaire to measure self-regulation strategies (i.e., locomotion and assessment). Well-being was measured using Ryff's Psychological Well-Being Scales short version, the Temporal Satisfaction with Life Scale, and the Positive Affect and Negative Affect Schedule. Exercise behaviour was self-reported using questions pertaining to frequency and intensity of exercise compliance. Academic achievement was operationalized through the pupils' mean value of final grades in Swedish, Mathematics, English, and Physical Education. Both correlation and regressions analyses were conducted. Results. Academic achievement was positively related to assessment, well-being, and frequent/intensive exercise behaviour. Assessment was, however, negatively related to well-being. Locomotion on the other hand was positively associated to well-being and also to exercise behaviour. Conclusions. The results suggest a dual (in)direct model to increase pupils' academic achievement and well-being-assessment being directly related to higher academic achievement, while locomotion is related to frequently exercising and well-being, which in turn, increase academic achievement. PMID:25861553

  3. Self-regulatory mode (locomotion and assessment), well-being (subjective and psychological), and exercise behavior (frequency and intensity) in relation to high school pupils’ academic achievement

    PubMed Central

    Jimmefors, Alexander; Mousavi, Fariba; Adrianson, Lillemor; Rosenberg, Patricia; Archer, Trevor

    2015-01-01

    Background. Self-regulation is the procedure implemented by an individual striving to reach a goal and consists of two inter-related strategies: assessment and locomotion. Moreover, both subjective and psychological well-being along exercise behaviour might also play a role on adolescents academic achievement. Method. Participants were 160 Swedish high school pupils (111 boys and 49 girls) with an age mean of 17.74 (sd = 1.29). We used the Regulatory Mode Questionnaire to measure self-regulation strategies (i.e., locomotion and assessment). Well-being was measured using Ryff’s Psychological Well-Being Scales short version, the Temporal Satisfaction with Life Scale, and the Positive Affect and Negative Affect Schedule. Exercise behaviour was self-reported using questions pertaining to frequency and intensity of exercise compliance. Academic achievement was operationalized through the pupils’ mean value of final grades in Swedish, Mathematics, English, and Physical Education. Both correlation and regressions analyses were conducted. Results. Academic achievement was positively related to assessment, well-being, and frequent/intensive exercise behaviour. Assessment was, however, negatively related to well-being. Locomotion on the other hand was positively associated to well-being and also to exercise behaviour. Conclusions. The results suggest a dual (in)direct model to increase pupils’ academic achievement and well-being—assessment being directly related to higher academic achievement, while locomotion is related to frequently exercising and well-being, which in turn, increase academic achievement. PMID:25861553

  4. [Spontaneous abortion. Etiologic survey. Results].

    PubMed

    Baaklini, N; Anguenot, J L; Boulanger, J C; Vitse, M

    1990-12-01

    The definition of repeated spontaneous abortions is subject to caution. For some, it corresponds to at least three repeated spontaneous abortions with no normal previous pregnancy; for others, it comprises the repeated spontaneous abortions occurring after a normal pregnancy. It is a frequent problem, especially if one tries to give a wider definition. The authors studied the frequency of repeated spontaneous abortions in a continuous series of 14,857 pregnancies which took place between January 1982 and December 1988. In the study of the aetiology of the repeated spontaneous abortions in the various groups of women defined according to the number of previous pregnancies and abortions, they find the classical causes of repeated spontaneous abortions in all the categories: therefore, it seems legitimate to them that a wider definition be given for repeated spontaneous abortions. PMID:2291048

  5. Management of Spontaneous Vaginal Delivery.

    PubMed

    Dresang, Lee T; Yonke, Nicole

    2015-08-01

    Most of the nearly 4 million births in the United States annually are normal spontaneous vaginal deliveries. In the first stage of labor, normal birth outcomes can be improved by encouraging the patient to walk and stay in upright positions, waiting until at least 6 cm dilation to diagnose active stage arrest, providing continuous labor support, using intermittent auscultation in low-risk deliveries, and following the Centers for Disease Control and Prevention guidelines for group B streptococcus prophylaxis. Most women with a low transverse uterine incision are candidates for a trial of labor after cesarean delivery and should be counseled accordingly. Pain management during labor includes complementary modalities and systemic opioids, epidural anesthesia, and pudendal block. Outcomes in the second stage of labor can be improved by using warm perineal compresses, allowing women more time to push before intervening, and offering labor support. Delayed pushing increases the length of the second stage of labor and does not affect the rate of spontaneous vaginal delivery. A tight nuchal cord can be clamped twice and cut before delivery of the shoulders, or the baby may be delivered using a somersault maneuver in which the cord is left nuchal and the distance from the cord to placenta minimized by pushing the head toward the maternal thigh. After delivery, skin-to-skin contact with the mother is recommended. Beyond 35 weeks' gestation, there is no benefit to bulb suctioning the nose and mouth. Postpartum maternal and neonatal outcomes can be improved through delayed cord clamping, active management to prevent postpartum hemorrhage, careful examination for external anal sphincter injuries, and use of absorbable synthetic suture for second-degree perineal laceration repair. Practices that will not improve outcomes and may result in negative outcomes include discontinuation of epidurals late in labor and routine episiotomy. PMID:26280140

  6. The adaptation of a reflex response to the ongoing phase of locomotion in fish.

    PubMed

    Grillner, S; Rossignol, S; Wallén, P

    1977-10-24

    The reflex response to stimulation of the tail fin has been studied in the swimming fish, by bilateral electromyographical (EMG) recordings in several segments along the body. The response varies with the phase of swimming. When the muscles on one side (segment) are active, a large response will occur on this side but no response on the contralateral side at the same level. When the other side becomes active an identical stimulus will cause an activation of this side but no response on the previously active side. When the movements were filmed a powerful mechanical effect was demonstrated with an augmentation of the ongoing movement, that would result in an instantaneous increase in speed. The stimulus causes in addition a shortening of the duration of the swimming cycle and its components. Most of the results were obtained on spinal dogfish, which also exhibits spontaneous locomotion after a spinal transection. Mainly electrical bipolar stimulation of the tail fin was used. Identical stimuli applied in different phases on an ongoing movement, thus give a reflex response that changes dramatically with the phase of the movement. This phase dependent reflex reversal is functionally meaningful; it is fast and due to spinal mechanisms. PMID:590408

  7. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION COMPLIANCE...

  8. The coal-fired gas turbine locomotive - A new look

    NASA Technical Reports Server (NTRS)

    Liddle, S. G.; Bonzo, B. B.; Purohit, G. P.

    1983-01-01

    Advances in turbomachine technology and novel methods of coal combustion may have made possible the development of a competitive coal fired gas turbine locomotive engine. Of the combustor, thermodynamic cycle, and turbine combinations presently assessed, an external combustion closed cycle regenerative gas turbine with a fluidized bed coal combustor is judged to be the best suited for locomotive requirements. Some merit is also discerned in external combustion open cycle regenerative systems and internal combustion open cycle regenerative gas turbine systems employing a coal gasifier. The choice of an open or closed cycle depends on the selection of a working fluid and the relative advantages of loop pressurization, with air being the most attractive closed cycle working fluid on the basis of cost.

  9. Spinal corollary discharge modulates motion sensing during vertebrate locomotion

    PubMed Central

    Chagnaud, Boris P.; Banchi, Roberto; Simmers, John; Straka, Hans

    2015-01-01

    During active movements, neural replicas of the underlying motor commands may assist in adapting motion-detecting sensory systems to an animal's own behaviour. The transmission of such motor efference copies to the mechanosensory periphery offers a potential predictive substrate for diminishing sensory responsiveness to self-motion during vertebrate locomotion. Here, using semi-isolated in vitro preparations of larval Xenopus, we demonstrate that shared efferent neural pathways to hair cells of vestibular endorgans and lateral line neuromasts express cyclic impulse bursts during swimming that are directly driven by spinal locomotor circuitry. Despite common efferent innervation and discharge patterns, afferent signal encoding at the two mechanosensory peripheries is influenced differentially by efference copy signals, reflecting the different organization of body/water motion-detecting processes in the vestibular and lateral line systems. The resultant overall gain reduction in sensory signal encoding in both cases, which likely prevents overstimulation, constitutes an adjustment to increased stimulus magnitudes during locomotion. PMID:26337184

  10. Emergence of adaptability to time delay in bipedal locomotion.

    PubMed

    Ohgane, Kunishige; Ei, Shin-Ichiro; Kazutoshi, Kudo; Ohtsuki, Tatsuyuki

    2004-02-01

    Based on neurophysiological evidence, theoretical studies have shown that locomotion is generated by mutual entrainment between the oscillatory activities of central pattern generators (CPGs) and body motion. However, it has also been shown that the time delay in the sensorimotor loop can destabilize mutual entrainment and result in the failure to walk. In this study, a new mechanism called flexible-phase locking is proposed to overcome the time delay. It is realized by employing the Bonhoeffer-Van der Pol formalism - well known as a physiologically faithful neuronal model - for neurons in the CPG. The formalism states that neurons modulate their phase according to the delay so that mutual entrainment is stabilized. Flexible-phase locking derives from the phase dynamics related to an asymptotically stable limit cycle of the neuron. The effectiveness of the mechanism is verified by computer simulations of a bipedal locomotion model. PMID:14999479

  11. Direct measurements of drag forces in C. elegans crawling locomotion.

    PubMed

    Rabets, Yegor; Backholm, Matilda; Dalnoki-Veress, Kari; Ryu, William S

    2014-10-21

    With a simple and versatile microcantilever-based force measurement technique, we have probed the drag forces involved in Caenorhabditis elegans locomotion. As a worm crawls on an agar surface, we found that substrate viscoelasticity introduces nonlinearities in the force-velocity relationships, yielding nonconstant drag coefficients that are not captured by original resistive force theory. A major contributing factor to these nonlinearities is the formation of a shallow groove on the agar surface. We measured both the adhesion forces that cause the worm's body to settle into the agar and the resulting dynamics of groove formation. Furthermore, we quantified the locomotive forces produced by C. elegans undulatory motions on a wet viscoelastic agar surface. We show that an extension of resistive force theory is able to use the dynamics of a nematode's body shape along with the measured drag coefficients to predict the forces generated by a crawling nematode. PMID:25418179

  12. Optimizing Locomotion Controllers Using Biologically-Based Actuators and Objectives

    PubMed Central

    Wang, Jack M.; Hamner, Samuel R.; Delp, Scott L.; Koltun, Vladlen

    2015-01-01

    We present a technique for automatically synthesizing walking and running controllers for physically-simulated 3D humanoid characters. The sagittal hip, knee, and ankle degrees-of-freedom are actuated using a set of eight Hill-type musculotendon models in each leg, with biologically-motivated control laws. The parameters of these control laws are set by an optimization procedure that satisfies a number of locomotion task terms while minimizing a biological model of metabolic energy expenditure. We show that the use of biologically-based actuators and objectives measurably increases the realism of gaits generated by locomotion controllers that operate without the use of motion capture data, and that metabolic energy expenditure provides a simple and unifying measurement of effort that can be used for both walking and running control optimization. PMID:26251560

  13. Theoretical and experimental study on a compliant flipper-leg during terrestrial locomotion.

    PubMed

    Fang, Tao; Zhou, Youcheng; Li, Shikun; Xu, Min; Liang, Haiyi; Li, Weihua; Zhang, Shiwu

    2016-01-01

    An amphibious robot with straight compliant flipper-legs can conquer various amphibious environments. The robot can rotate its flipper-legs and utilize their large deflection to walk on rough terrain, and it can oscillate the straight flipper-legs to propel itself underwater. This paper focuses on the dynamics of the compliant straight flipper-legs during terrestrial locomotion by modeling its deformation dynamically with large deflection theory and simulating it to investigate the parameters of locomotion such as trajectory, velocity, and propulsion. To validate the theoretical model of dynamic locomotion, a single-leg experimental platform is used to explore the flipper-legs in motion with various structural and kinematic parameters. Furthermore, a robotic platform mounting with four compliant flipper-legs is also developed and used to experiment with locomotion. The trajectories of the rotating axle of the compliant flipper-leg during locomotion were approximately coincidental in simulation and in experiments. The speed of locomotion and cost of transport during locomotion were explored and analyzed. The performance of different types of compliant flipper-legs during locomotion shows that varying the degrees of stiffness will have a significant effect on their locomotion. The dynamic model and analysis of the compliant flipper-leg for terrestrial locomotion facilitates the ability of amphibious robots to conquer complex environments. PMID:27530372

  14. Dynamics of entanglement between two atomic samples with spontaneous scattering

    SciTech Connect

    Di Lisi, Antonio; De Siena, Silvio; Illuminati, Fabrizio

    2004-07-01

    We investigate the effects of spontaneous scattering on the evolution of entanglement of two atomic samples, probed by phase-shift measurements on optical beams interacting with both samples. We develop a formalism of conditional quantum evolutions and present a wave function analysis implemented in numerical simulations of the state vector dynamics. This method allows us to track the evolution of entanglement and to compare it with the predictions obtained when spontaneous scattering is neglected. We provide numerical evidence that the interferometric scheme to entangle atomic samples is only marginally affected by the presence of spontaneous scattering and should thus be robust even in more realistic situations.

  15. Ground reaction forces during human locomotion on railroad ballast.

    PubMed

    Wade, Chip; Redfern, Mark S

    2007-11-01

    Locomotion over ballast surfaces provides a unique situation for investigating the biomechanics of gait. Although much research has focused on level and sloped walking on a smooth, firm surface in order to understand the common kinematic and kinetic variables associated with human locomotion, the literature currently provides few if any discussions regarding the dynamics of locomotion on surfaces that are either rocky or uneven. The purpose of this study was to investigate a method for using force plates to measure the ground reaction forces (GRFs) during gait on ballast. Ballast is a construction aggregate of unsymmetrical rock used in industry for the purpose of forming track bed on which railway ties are laid or in yards where railroad cars are stored. It is used to facilitate the drainage of water and to create even running surfaces. To construct the experimental ballast surfaces, 31.75 mm (1 1/4 in.) marble ballast at depths of approximately 63.5 mm (2.5 in.) or 101.6 mm (4 in.) were spread over a carpeted vinyl tile walkway specially designed for gait studies. GRF magnitudes and time histories from a force plate were collected under normal smooth surface and under both ballast surface conditions for five subjects. GRF magnitudes and time histories during smooth surface walking were similar to GRF magnitudes and time histories from the two ballast surface conditions. The data presented here demonstrate the feasibility of using a force plate system to expand the scope of biomechanical analyses of locomotion on ballast surfaces. PMID:18089931

  16. Performance analysis of jump-gliding locomotion for miniature robotics.

    PubMed

    Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M

    2015-04-01

    Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the 'EPFL jump-glider'. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs. PMID:25811417

  17. A terradynamics of legged locomotion on granular media

    NASA Astrophysics Data System (ADS)

    Li, Chen; Zhang, Tingnan; Goldman, Daniel

    2013-03-01

    The theories of aero and hydrodynamics form the bases for prediction of animal movement and device design in air and water, and allow computation of lift, drag, and thrust forces on wings and fins. While models of terrestrial legged locomotion have focused on interactions with solid ground, many legged animals (and increasingly robots) move on substrates such as sand, gravel, soil, mud, snow, grass, and leaf litter that flow in response to intrusion. However, locomotor-ground interaction models on such flowable ground are often unavailable. Here we develop a resistive force model that predicts forces on arbitrary-shaped legs and bodies moving freely in granular media in the vertical plane. Our resistive force measurements reveal a complex but generic dependence of stresses on an intruder on its depth, orientation, and movement direction in granular media of different particle size, density, friction, and compaction. Our resistive force model and a multi-body simulation predict a small legged robot's locomotion on granular media using various leg shapes and stride frequencies, and give insight into the effects of leg morphology and kinematics on movement on granular media. Our study is an initial but important step in creation of ``terradynamics'' of locomotion on flowable ground.

  18. Kinematics of treadmill locomotion in mice raised in hypergravity.

    PubMed

    Bojados, Mickael; Herbin, Marc; Jamon, Marc

    2013-05-01

    The study compared the motor performance of adult C57Bl/6J mice previously exposed to a 2G gravity environment during different periods of their development. 12 mice were housed in a large diameter centrifuge from the conception to Postnatal day 10 (P10). Another group of 10 mice was centrifuged form P10 to P30, and a third group of 9 mice was centrifuged from conception to P30. Their gait parameters, and kinematics of joint excursions were compared with 11 control mice, at the age of 2 months using a video-radiographic apparatus connected to a motorized treadmill. The mice that returned to Earth gravity level at the age of P10 showed a motor pattern similar to control mice. At variance the two groups that were centrifuged from P10 to P30 showed a different motor pattern with smaller and faster strides to walk at the same velocity as controls. On the other hand all the centrifuged mice showed significant postural changes, particularly with a more extended ankle joint, but the mice centrifuged during the whole experimental period differed even more. Our results showed that the exposure to hypergravity before P10 sufficed to modify the posture, suggesting that postural control starts before the onset of locomotion, whereas the gravity constraint perceived between P10 and P30 conditioned the tuning of quadruped locomotion with long term consequences. These results support the existence of a critical period in the acquisition of locomotion in mice. PMID:23352767

  19. Children's locomotion on slopes given visual, acoustic, and tactile information.

    PubMed

    Alexandre, R; Cordovil, R; Barreiros, J

    2012-08-01

    The effects of visual, acoustic, and tactile information on 5 blind and 5 sighted children's locomotion on slopes (10 degrees, 15 degrees, 20 degrees, 25 degrees, and 30 degrees) were investigated. Children's ages ranged from 5.8 to 7.7 years (M= 6.8, SD= 0.7). The sighted children performed the task of walking up and down different slopes blindfolded and with full vision. Locomotion modes, locomotor skill, gait deviation, and time to complete the task were analyzed. Walking was the preferred locomotion mode up to 20 degrees, but steeper slopes were perceived as "non-walkable." Doubly multivariate MANOVAs revealed an effect of visual information (blindfolded vs full vision) on the sighted children's gait patterns, and a significant interaction between cue condition and group (blind vs blindfolded), underlining a distinct influence of the cues in the gait patterns of the two groups of children. Acoustic and tactile cues were generally more effective for the blind than for the sighted blindfolded children. PMID:23033757

  20. Instability-based mechanism for body undulations in centipede locomotion

    NASA Astrophysics Data System (ADS)

    Aoi, Shinya; Egi, Yoshimasa; Tsuchiya, Kazuo

    2013-01-01

    Centipedes have many body segments and legs and they generate body undulations during terrestrial locomotion. Centipede locomotion has the characteristic that body undulations are absent at low speeds but appear at faster speeds; furthermore, their amplitude and wavelength increase with increasing speed. There are conflicting reports regarding whether the muscles along the body axis resist or support these body undulations and the underlying mechanisms responsible for the body undulations remain largely unclear. In the present study, we investigated centipede locomotion dynamics using computer simulation with a body-mechanical model and experiment with a centipede-like robot and then conducted dynamic analysis with a simple model to clarify the mechanism. The results reveal that body undulations in these models occur due to an instability caused by a supercritical Hopf bifurcation. We subsequently compared these results with data obtained using actual centipedes. The model and actual centipedes exhibit similar dynamic properties, despite centipedes being complex, nonlinear dynamic systems. Based on our findings, we propose a possible passive mechanism for body undulations in centipedes, similar to a follower force or jackknife instability. We also discuss the roles of the muscles along the body axis in generating body undulations in terms of our physical model.

  1. On the feasibility of life-saving locomotive bumpers.

    PubMed

    Paden, Brad E; Kelly, Paraic M; Hines, Jacob A; Bothman, David; Simms, Ciaran

    2016-04-01

    Motivated by the thousands of pedestrians killed each year in train impacts, this paper investigates the life-saving capability of four high-level locomotive bumper concepts. The head motions produced by the four concepts are modeled as one or two square acceleration pulses and are analyzed using the Head Injury Criterion (HIC). Surprisingly, the analyses show that all four concepts can achieve HIC values of less than 200 for an impact with a locomotive traveling at 100 km/h. Two of the concepts eject the pedestrian trackside with at a velocity of roughly 40 km/h and the risk of ground-impact injury is discussed in the context of related automobile accident data. The computed bumper lengths are a fraction of the overall length of a locomotive and are thus feasible for practical implementation. One concept involves an oblique impact and the potential for rotational head injury is analyzed. This basic feasibility research motivates future investigations into the detailed design of bumper shapes, multi-body pedestrian simulations, and finite-element injury models. PMID:26866281

  2. Spontaneous Tumor Lysis Syndrome

    PubMed Central

    Kimple, Michelle E.

    2015-01-01

    Tumor lysis syndrome (TLS) is a known complication of malignancy and its treatment. The incidence varies on malignancy type, but is most common with hematologic neoplasms during cytotoxic treatment. Spontaneous TLS is thought to be rare. This case study is of a 62-year-old female admitted with multisystem organ failure, with subsequent diagnosis of aggressive B cell lymphoma. On admission, laboratory abnormalities included renal failure, elevated uric acid (20.7 mg/dL), and 3+ amorphous urates on urinalysis. Oliguric renal failure persisted despite aggressive hydration and diuretic use, requiring initiation of hemodialysis prior to chemotherapy. Antihyperuricemic therapy and hemodialysis were used to resolve hyperuricemia. However, due to multisystem organ dysfunction syndrome with extremely poor prognosis, the patient ultimately expired in the setting of a terminal ventilator wean. Although our patient did not meet current TLS criteria, she required hemodialysis due to uric acid nephropathy, a complication of TLS. This poses the clinical question of whether adequate diagnostic criteria exist for spontaneous TLS and if the lack of currently accepted guidelines has resulted in the underestimation of its incidence. Allopurinol and rasburicase are commonly used for prevention and treatment of TLS. Although both drugs decrease uric acid levels, allopurinol mechanistically prevents formation of the substrate rasburicase acts to solubilize. These drugs were administered together in our patient, although no established guidelines recommend combined use. This raises the clinical question of whether combined therapy is truly beneficial or, conversely, detrimental to patient outcomes. PMID:26904699

  3. Quantum Spontaneous Stochasticity

    NASA Astrophysics Data System (ADS)

    Drivas, Theodore; Eyink, Gregory

    Classical Newtonian dynamics is expected to be deterministic, but recent fluid turbulence theory predicts that a particle advected at high Reynolds-numbers by ''nearly rough'' flows moves nondeterministically. Small stochastic perturbations to the flow velocity or to the initial data lead to persistent randomness, even in the limit where the perturbations vanish! Such ``spontaneous stochasticity'' has profound consequences for astrophysics, geophysics, and our daily lives. We show that a similar effect occurs with a quantum particle in a ''nearly rough'' force, for the semi-classical (large-mass) limit, where spreading of the wave-packet is usually expected to be negligible and dynamics to be deterministic Newtonian. Instead, there are non-zero probabilities to observe multiple, non-unique solutions of the classical equations. Although the quantum wave-function remains split, rapid phase oscillations prevent any coherent superposition of the branches. Classical spontaneous stochasticity has not yet been seen in controlled laboratory experiments of fluid turbulence, but the corresponding quantum effects may be observable by current techniques. We suggest possible experiments with neutral atomic-molecular systems in repulsive electric dipole potentials.

  4. Simultaneous bilateral spontaneous pneumothorax.

    PubMed

    Graf-Deuel, E; Knoblauch, A

    1994-04-01

    We describe 12 patients with simultaneous bilateral spontaneous pneumothorax (SBSP). They represent 4 percent of patients with spontaneous pneumothorax seen at our hospital from 1971 to 1990. Five of the 12 had no underlying lung disease. In the seven remaining patients, SBSP was secondary to histiocytosis X, lymphangioleiomyomatosis, osteogenic sarcoma with pleural and pulmonary metastases, Hodgkin's disease, mesothelioma, cystic fibrosis, or miliary tuberculosis. Nineteen of the 56 patients with SBSP (34 percent) described in the literature (this series included) had pulmonary disease related to disorders of cells of mesenchymal origin. Emphysema and bullous lung disease were not associated with SBSP. Long-term prognosis was a function of pulmonary status. Four of the patients described herein died during the period reviewed. All suffered from severe underlying disease. In no case was SBSP the main cause of death. With timely treatment, the short-term prognosis is benign even for patients with underlying lung disease. Surgical pleurectomy should be attempted early, especially in SBSP secondary to underlying lung disease. PMID:8162740

  5. Experience of Time by People on the Go: A Theory of the Locomotion-Temporality Interface.

    PubMed

    Kruglanski, Arie W; Pierro, Antonio; Higgins, E Tory

    2016-05-01

    We explore the psychological interface of time and motion.Locomotion, the proclivity toward movement and change, constitutes a significant determinant of persons' orientation toward time, both as a valuable resource and as a flow advancing from past to future. High locomotors act quickly, multitask and refrain from procrastination, thus conserving time as are source Their preoccupation with movement, moreover, affects their relation to the flow of time High locomotors are future oriented and eschew preoccupation with the past. They are optimistic, experience little regret, generate few counterfactuals, feel little guilt about past wrongdoings, and leave behind past friends. Evidence accumulates that locomotors' "fast forward" orientation pervades diverse aspects of their behavior and has significant consequences for individuals and societies. PMID:25862368

  6. Actin flows in cell migration: from locomotion and polarity to trajectories.

    PubMed

    Callan-Jones, Andrew C; Voituriez, Raphaël

    2016-02-01

    Eukaryotic cell movement is characterized by very diverse migration modes. Recent studies show that cells can adapt to environmental cues, such as adhesion and geometric confinement, thereby readily switching their mode of migration. Among this diversity of motile behavior, actin flows have emerged as a highly conserved feature of both mesenchymal and amoeboid migration, and have also been identified as key regulators of cell polarity. This suggests that the various observed migration modes are continuous variations of elementary locomotion mechanisms, based on a very robust physical property of the actin/myosin system - its ability to sustain flows at the cell scale. This central role of actin/myosin flows is shown to affect the large scale properties of cell trajectories. PMID:26827283

  7. Locomotion training of legged robots using hybrid machine learning techniques

    NASA Technical Reports Server (NTRS)

    Simon, William E.; Doerschuk, Peggy I.; Zhang, Wen-Ran; Li, Andrew L.

    1995-01-01

    In this study artificial neural networks and fuzzy logic are used to control the jumping behavior of a three-link uniped robot. The biped locomotion control problem is an increment of the uniped locomotion control. Study of legged locomotion dynamics indicates that a hierarchical controller is required to control the behavior of a legged robot. A structured control strategy is suggested which includes navigator, motion planner, biped coordinator and uniped controllers. A three-link uniped robot simulation is developed to be used as the plant. Neurocontrollers were trained both online and offline. In the case of on-line training, a reinforcement learning technique was used to train the neurocontroller to make the robot jump to a specified height. After several hundred iterations of training, the plant output achieved an accuracy of 7.4%. However, when jump distance and body angular momentum were also included in the control objectives, training time became impractically long. In the case of off-line training, a three-layered backpropagation (BP) network was first used with three inputs, three outputs and 15 to 40 hidden nodes. Pre-generated data were presented to the network with a learning rate as low as 0.003 in order to reach convergence. The low learning rate required for convergence resulted in a very slow training process which took weeks to learn 460 examples. After training, performance of the neurocontroller was rather poor. Consequently, the BP network was replaced by a Cerebeller Model Articulation Controller (CMAC) network. Subsequent experiments described in this document show that the CMAC network is more suitable to the solution of uniped locomotion control problems in terms of both learning efficiency and performance. A new approach is introduced in this report, viz., a self-organizing multiagent cerebeller model for fuzzy-neural control of uniped locomotion is suggested to improve training efficiency. This is currently being evaluated for a possible

  8. Behavioural toxicity assessment of silver ions and nanoparticles on zebrafish using a locomotion profiling approach.

    PubMed

    Ašmonaitė, Giedrė; Boyer, Scott; Souza, Karine Bresolin de; Wassmur, Britt; Sturve, Joachim

    2016-04-01

    Zebrafish (Danio rerio) is not only a widely used species in the Fish Embryo Toxicity (FET) test but also an emerging model in behavioural ecotoxicology. By using automatic behaviour tracking technology, locomotion of developing zebrafish (ZF) larvae can be accurately recorded and potentially used in an ecotoxicological context to detect toxicant-induced behavioural alterations. In this study, we explored if and how quantitative locomotion data can be used for sub-lethal toxicity testing within the FET framework. We exposed ZF embryos to silver ions and nanoparticles, which previously have been reported to cause neurodevelopmental toxicity and behavioural retardation in early-life stages of ZF. Exposure to a broad range of silver (Ag(+) and AgNPs) concentrations was conducted, and developmental toxicity was assessed using FET criteria. For behavioural toxicity assessment, locomotion of exposed ZF eleutheroembryos (120hpf) was quantified according to a customised behavioural assay in an automatic video tracking system. A set of repeated episodes of dark/light stimulation were used to artificially stress ZF and evoke photo-motor responses, which were consequently utilized for locomotion profiling. Our locomotion-based behaviour profiling approach consisted of (1) dose-response ranking for multiple and single locomotion variables; (2) quantitative assessment of locomotion structure; and (3) analysis of ZF responsiveness to darkness stimulation. We documented that both silver forms caused adverse effects on development and inhibited hatchability and, most importantly, altered locomotion. High Ag(+) and AgNPs exposures significantly suppressed locomotion and a clear shift in locomotion towards inactivity was reported. Additionally, we noted that low, environmentally relevant Ag(+) concentrations may cause subordinate locomotive changes (hyperactivity) in developing fish. Overall, it was concluded that our locomotion-based behaviour-testing scheme can be used jointly

  9. Spontaneously broken complete relativity

    NASA Astrophysics Data System (ADS)

    Andreev, A. F.

    1982-08-01

    It is suggested that the equations of the theory of relativity should have a spontaneously broken invariance with respect to the complex Poincare group, in order that relative velocities stay below that of light. Lorentz transformation matrices corresponding to velocities higher than that of light, which contain imaginary elements, are combined with real transformations in a single group, requiring the introduction of a complex Lorentz group as a symmetry group. For this complex group to be realized in real, physical space-time, the complex character of the coordinates must be eliminated by introducing appropriate Goldstone fields. The properties of these Goldstone fiels are discussed. A massless Goldstone field is deduced which, in the linear approximation, has no manifestations of any sort in classical mechanics and whose sole macroscopic manifestation is the presence of a nonelectromagnetic long-range interaction of bodies having a nonvanishing average spin density. An experiment to detect such a field is suggested.

  10. Spontaneous Atherosclerosis in Pigeons

    PubMed Central

    Santerre, Robert F.; Wight, Thomas N.; Smith, Samuel C.; Brannigan, David

    1972-01-01

    The interpretation of metabolic studies related to early changes in spontaneous atherosclerosis has been hampered by the focal nature of the disease and by the lack of a well-defined model system of the disease process. Gross, histologic and ultrastructural observations of lesion development at the celiac bifurcation of the aorta in atherosclerosis-susceptible White Carneau and atherosclerosis-resistant Show Racer pigeons are compared and discussed in terms of hemodynamics, muscular aggregation and altered metabolism of smooth muscle cells. Detailed knowledge of the morphologic sequence of events in lesion localization makes the celiac bifurcation in White Carneau and Show Racer pigeons a useful model for genetic comparisons of arterial wall metabolism and for investigating metabolic alterations occurring with atherogenesis. ImagesFig 9Fig 10Fig 1Fig 2Fig 10Fig 11Fig 3Fig 4Fig 12Fig 5Fig 6Fig 7Fig 8 PMID:4261591

  11. Spontaneous Iliac Vein Rupture

    PubMed Central

    Kim, Dae Hwan; Park, Hyung Sub; Lee, Taeseung

    2015-01-01

    Spontaneous iliac vein rupture (SIVR) is a rare entity, which usually occurs without a precipitating factor, but can be a life-threatening emergency often requiring an emergency operation. This is a case report of SIVR in a 62-year-old female who presented to the emergency room with left leg swelling. Workup with contrast-enhanced computed tomography revealed a left leg deep vein thrombosis with May-Thurner syndrome and a hematoma in the pelvic cavity without definite evidence of arterial bleeding. She was managed conservatively without surgical intervention, and also underwent inferior vena cava filter insertion and subsequent anticoagulation therapy for pulmonary thromboembolism. This case shows that SIVR can be successfully managed with close monitoring and conservative management, and anticoagulation may be safely applied despite the patient presenting with venous bleeding. PMID:26217647

  12. Spontaneous aortocaval fistula.

    PubMed

    Rajmohan, B

    2002-01-01

    Spontaneous aortocaval fistula is rare, occurring only in 4% of all ruptured abdominal aortic aneurysms. The physical signs can be missed but the presence of low back pain, palpable abdominal aortic aneurysm, machinery abdominal murmur and high-output cardiac failure unresponsive to medical treatment should raise the suspicion. Pre-operative diagnosis is crucial, as adequate preparation has to be made for the massive bleeding expected at operation. Successful treatment depends on management of perioperative haemodynamics, control of bleeding from the fistula and prevention of deep vein thrombosis and pulmonary embolism. Surgical repair of an aortocaval fistula is now standardised--repair of the fistula from within the aneurysm (endoaneurysmorraphy) followed by prosthetic graft replacement of the aneurysm. A case report of a 77-year-old woman, initially suspected to have unstable angina but subsequently diagnosed to have an aortocaval fistula and surgically treated successfully, is presented along with a review of literature. PMID:12432197

  13. Spontaneous Coronary Artery Dissection.

    PubMed

    Tweet, Marysia S; Gulati, Rajiv; Hayes, Sharonne N

    2016-07-01

    Spontaneous coronary artery dissection is an important etiology of nonatherosclerotic acute coronary syndrome, myocardial infarction, and sudden death. Innovations in the catheterization laboratory including optical coherence tomography and intravascular ultrasound have enhanced the ability to visualize intimal disruption and intramural hematoma associated with SCAD. Formerly considered "rare," these technological advances and heightened awareness suggest that SCAD is more prevalent than prior estimates. SCAD is associated with female sex, young age, extreme emotional stress, or extreme exertion, pregnancy, and fibromuscular dysplasia. The clinical characteristics and management strategies of SCAD patients are different than for atherosclerotic heart disease and deserve specific consideration. This review will highlight recent discoveries about SCAD as well as describe current efforts to elucidate remaining gaps in knowledge. PMID:27216840

  14. Modelling human locomotion: applications to cycling.

    PubMed

    Olds, T

    2001-01-01

    Mathematical models of performance in locomotor sports are reducible to functions of the sort y = f(x) where y is some performance variable, such as time, distance or speed, and x is a combination of predictor variables which may include expressions for power (or energy) supply and/or demand. The most valid and useful models are first-principles models that equate expressions for power supply and power demand. Power demand in cycling is the sum of the power required to overcome air resistance and rolling resistance, the power required to change the kinetic energy of the system, and the power required to ride up or down a grade. Power supply is drawn from aerobic and anaerobic sources, and modellers must consider not only the rate but also the kinetics and pattern of power supply. The relative contributions of air resistance to total demand, and of aerobic energy to total supply, increase curvilinearly with performance time, while the importance of other factors decreases. Factors such as crosswinds, aerodynamic accessories and drafting can modify the power demand in cycling, while body configuration/orientation and altitude will affect both power demand and power supply, often in opposite directions. Mathematical models have been used to solve specific problems in cycling, such as the chance of success of a breakaway, the optimal altitude for performance, creating a 'level playing field' to compare performances for selection purposes, and to quantify, in the common currency of minutes and seconds, the effects on performance of changes in physiological, environmental and equipment variables. The development of crank dynamometers and portable gas-analysis systems, combined with a modelling approach, will in the future provide valuable information on the effect of changes in equipment, configuration and environment on both supply and demand-side variables. PMID:11428687

  15. Management factors associated with impaired locomotion in dairy cows in England and Wales.

    PubMed

    Barker, Z E; Amory, J R; Wright, J L; Blowey, R W; Green, L E

    2007-07-01

    Forty-nine farms in England and Wales were visited on 4 occasions between February 2003 and March 2004. A total of 21,693 scores of locomotion were assigned to 7,722 cattle. Locomotion was assessed on a 3-point scale by observing the posture of a cow's back while standing and walking (1 = sound, 2 = not sound, 3 = lame). Data on measurable factors potentially associated with locomotion were collected from all farms using direct observations of the farm environment and a comprehensive farmer interview. The mean herd locomotion score was 1.77 +/- 0.02. There was no significant difference in mean herd locomotion scores between 5 herds housed in straw yards (1.72 +/- 0.02) and 44 herds housed in free stalls (1.78 +/- 0.02), possibly because of lack of power. A GLM was produced using data from the 44 herds housed in free stalls, with the mean farm locomotion score of all cows examined on all 4 visits as the outcome variable. Factors associated with an elevated locomotion score were dry cows kept in straw yards compared with free stalls (increase in locomotion score = 0.06 +/- 0.03), pregnant heifers kept with milking cows in winter compared with being kept with dry cows (increase in locomotion score = 0.09 +/- 0.03), aisle widths of < 3 m compared with widths of > or = 3 m (increase in locomotion score = 0.06 +/- 0.02), a curb height of < or = 15 cm compared with a height of > 15 cm (increase in locomotion score = 0.07 +/- 0.03), routine trimming of hooves of all cows by a hoof trimmer or by the farmer compared with no routine hoof trimming (increase in locomotion score = 0.18 +/- 0.04 and 0.13 +/- 0.03 respectively), feeding corn silage to milking cows compared with feeding other forage types (increase in locomotion score = 0.10 +/- 0.03), and the use of automatic scrapers in the free-stall barn compared with tractor scrapers (increase in locomotion score = 0.10 +/- 0.03). These variables were correlated with many other management variables. The use of automatic

  16. On predatory wasps and zombie cockroaches: Investigations of "free will" and spontaneous behavior in insects.

    PubMed

    Gal, Ram; Libersat, Frederic

    2010-09-01

    Accumulating evidence suggest that nonhuman organisms, including invertebrates, possess the ability to make non-random choices based purely on ongoing and endogenously-created neuronal processes. We study this precursor of spontaneity in cockroaches stung by A. compressa, a parasitoid wasp that employs cockroaches as a live food supply for its offspring. This wasp uses a neurotoxic venom cocktail to 'hijack' the nervous system of its cockroach prey and manipulate specific features of its decision making process, thereby turning the cockroach into a submissive 'zombie' unable to self-initiate locomotion. We discuss different behavioral and physiological aspects of this venom-induced 'zombified state' and highlight at least one neuronal substrate involved in the regulation of spontaneous behavior in insects. PMID:21057640

  17. Spontaneous curvature of phosphatidic acid and lysophosphatidic acid.

    PubMed

    Kooijman, Edgar E; Chupin, Vladimir; Fuller, Nola L; Kozlov, Michael M; de Kruijff, Ben; Burger, Koert N J; Rand, Peter R

    2005-02-15

    The formation of phosphatidic acid (PA) from lysophosphatidic acid (LPA), diacylglycerol, or phosphatidylcholine plays a key role in the regulation of intracellular membrane fission events, but the underlying molecular mechanism has not been resolved. A likely possibility is that PA affects local membrane curvature facilitating membrane bending and fission. To examine this possibility, we determined the spontaneous radius of curvature (R(0p)) of PA and LPA, carrying oleoyl fatty acids, using well-established X-ray diffraction methods. We found that, under physiological conditions of pH and salt concentration (pH 7.0, 150 mM NaCl), the R(0p) values of PA and LPA were -46 A and +20 A, respectively. Thus PA has considerable negative spontaneous curvature while LPA has the most positive spontaneous curvature of any membrane lipid measured to date. The further addition of Ca(2+) did not significantly affect lipid spontaneous curvature; however, omitting NaCl from the hydration buffer greatly reduced the spontaneous curvature of PA, turning it into a cylindrically shaped lipid molecule (R(0p) of -1.3 x 10(2) A). Our quantitative data on the spontaneous radius of curvature of PA and LPA at a physiological pH and salt concentration will be instrumental in developing future models of biomembrane fission. PMID:15697235

  18. Sexuality of Disabled Athletes Depending on the Form of Locomotion

    PubMed Central

    Plinta, Ryszard; Sobiecka, Joanna; Drosdzol-Cop, Agnieszka; Nowak-Brzezińska, Agnieszka; Skrzypulec-Plinta, Violetta

    2015-01-01

    The main purpose of this study was to determine sexuality of disabled athletes depending on the form of locomotion. The study included 170 disabled athletes, aged between 18 and 45. The entire population was divided into 3 research groups depending on the form of locomotion: moving on wheelchairs (n=52), on crutches (n=29) and unaided (n=89). The research tool was a questionnaire voluntarily and anonymously completed by the respondents of the research groups. The questionnaire was composed of a general part concerning the socio-demographic conditions, medical history, health problems, a part dedicated to physical disability as well as the Polish version of the International Index of Erectile Function (IIEF) and the Female Sexual Function Index (FSFI) evaluating sexual life. STATISTICA 10.0 for Windows was used in the statistical analysis. Subjects moving on crutches were significantly older than ones moving on wheelchairs and unaided (34.41 ±11.00 vs. 30.49 ±10.44 and 27.99 ±10.51 years, respectively) (p=0.018). Clinically significant erectile dysfunctions were most often diagnosed in athletes moving on wheelchairs (70.27%), followed by athletes moving on crutches and moving unaided (60% and 35.42%, respectively; p=0.048). Clinical sexual dysfunctions were diagnosed on a similar level among all female athletes. It was concluded that the form of locomotion may determine sexuality of disabled men. Males on wheelchair revealed the worst sexual functioning. Female athletes moving on wheelchairs, on crutches and moving unaided were comparable in the aspect of their sexual life. PMID:26834876

  19. Comparative energetics of mammalian locomotion: humans are not different.

    PubMed

    Halsey, L G; White, C R

    2012-11-01

    Debates about the evolution of human bipedality sometimes include discussion on the energy costs of terrestrial locomotion of extinct and extant hominins. However, comparative analyses of hominin transport costs conducted to date have been limited and potentially misinforming, in part because they fail to consider phylogenetic history. In the present study, we compare the measured costs of pedestrian locomotion in humans and the estimated costs for Australopithecus afarensis (an early bipedal hominin), to a database of locomotory costs for mammals. Using data for 81 species of mammal, we demonstrate significant phylogenetic signal in both log-transformed body mass (logMass) and log-transformed net cost of transport (logNCOT), but no phylogenetic signal in residuals of the relationship between logNCOT and logMass. We then used this relationship to generate a prediction line for NCOT based on body mass, and compared this prediction with published measured data for NCOT of running and walking in humans, and estimated NCOT of walking in A. afarensis. The cost of human walking was 25% lower than predicted, while the cost of running was 27% higher. The cost of A. afarensis walking was 32% lower than predicted. However, all of these data points fall within the 95% prediction interval for mammals, indicating that they are not significantly lower or higher than predicted for other mammals of similar mass. Moreover, the difference between humans and our closest living relative the common chimpanzee is comparable to differences between other similarly closely related species. We therefore conclude that there is no evidence from metabolic data that humans, or A. afarensis, have/had a reduced energy cost of pedestrian locomotion compared to other mammals in general. PMID:22963931

  20. Emulating constant acceleration locomotion mechanics on a treadmill.

    PubMed

    Farris, Dominic James

    2016-03-21

    Locomotion on an accelerating treadmill belt is not dynamically similar to overground acceleration. The purpose of this study was to test if providing an external force to compensate for inertial forces during locomotion on an accelerating treadmill belt could induce locomotor dynamics similar to real accelerations. Nine males (mean±sd age=26±4 years, mass=81±9kg, height=1.8±0.05m) began walking and transitioned to running on an accelerating instrumented treadmill belt at three accelerations (0.27ms(-2), 0.42ms(-2), 0.76ms(-2)). Half the trials were typical treadmill locomotion (TT) and half were emulated acceleration (EA), where elastic tubing harnessed to the participant provided a horizontal force equal to mass multiplied by acceleration. Net mechanical work (WCOM) and ground reaction force impulses (IGRF) were calculated for individual steps and a linear regression was performed with these experimental measures as independent variables and theoretically derived values of work and impulse as predictor variables. For EA, linear fits were significant for WCOM (y=1.19x+10.5, P<0.001, R(2)=0.41) and IGRF (y=0.95x+8.1, P<0.001, R(2)=0.3). For TT, linear fits were not significant and explained virtually no variance for WCOM (y=0.06x+1.6, P=0.29, R(2)<0.01) and IGRF (y=0.10x+0.4, P=0.06, R(2)=0.01). This suggested that the EA condition was a better representation of real acceleration dynamics than TT. Running steps from EA where work and impulse closely matched theoretical values showed similar adaptations to increasing acceleration as have been previously observed overground (forward reorientation of GRF vector without an increase in magnitude or change in spatio-temporal metrics). PMID:26897649