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Sample records for interpret theropod walking

  1. Walking like dinosaurs: chickens with artificial tails provide clues about non-avian theropod locomotion.

    Science.gov (United States)

    Grossi, Bruno; Iriarte-Díaz, José; Larach, Omar; Canals, Mauricio; Vásquez, Rodrigo A

    2014-01-01

    Birds still share many traits with their dinosaur ancestors, making them the best living group to reconstruct certain aspects of non-avian theropod biology. Bipedal, digitigrade locomotion and parasagittal hindlimb movement are some of those inherited traits. Living birds, however, maintain an unusually crouched hindlimb posture and locomotion powered by knee flexion, in contrast to the inferred primitive condition of non-avian theropods: more upright posture and limb movement powered by femur retraction. Such functional differences, which are associated with a gradual, anterior shift of the centre of mass in theropods along the bird line, make the use of extant birds to study non-avian theropod locomotion problematic. Here we show that, by experimentally manipulating the location of the centre of mass in living birds, it is possible to recreate limb posture and kinematics inferred for extinct bipedal dinosaurs. Chickens raised wearing artificial tails, and consequently with more posteriorly located centre of mass, showed a more vertical orientation of the femur during standing and increased femoral displacement during locomotion. Our results support the hypothesis that gradual changes in the location of the centre of mass resulted in more crouched hindlimb postures and a shift from hip-driven to knee-driven limb movements through theropod evolution. This study suggests that, through careful experimental manipulations during the growth phase of ontogeny, extant birds can potentially be used to gain important insights into previously unexplored aspects of bipedal non-avian theropod locomotion.

  2. Walking like dinosaurs: chickens with artificial tails provide clues about non-avian theropod locomotion.

    Directory of Open Access Journals (Sweden)

    Bruno Grossi

    Full Text Available Birds still share many traits with their dinosaur ancestors, making them the best living group to reconstruct certain aspects of non-avian theropod biology. Bipedal, digitigrade locomotion and parasagittal hindlimb movement are some of those inherited traits. Living birds, however, maintain an unusually crouched hindlimb posture and locomotion powered by knee flexion, in contrast to the inferred primitive condition of non-avian theropods: more upright posture and limb movement powered by femur retraction. Such functional differences, which are associated with a gradual, anterior shift of the centre of mass in theropods along the bird line, make the use of extant birds to study non-avian theropod locomotion problematic. Here we show that, by experimentally manipulating the location of the centre of mass in living birds, it is possible to recreate limb posture and kinematics inferred for extinct bipedal dinosaurs. Chickens raised wearing artificial tails, and consequently with more posteriorly located centre of mass, showed a more vertical orientation of the femur during standing and increased femoral displacement during locomotion. Our results support the hypothesis that gradual changes in the location of the centre of mass resulted in more crouched hindlimb postures and a shift from hip-driven to knee-driven limb movements through theropod evolution. This study suggests that, through careful experimental manipulations during the growth phase of ontogeny, extant birds can potentially be used to gain important insights into previously unexplored aspects of bipedal non-avian theropod locomotion.

  3. Predatory behaviour of carnivorous dinosaurs: Ecological interpretations based on tooth marked dinosaur bones and wear patterns of theropod teeth

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    Predation marks on bones are a source on information on the feeding behaviour of the carnivores involved. Although predator damaged bone is common in the fossil record, published reports of such marks on dinosaur bones are rare. Patterns of bone modification by mammalian carnivores overlap patterns...... left by theropod dinosaurs.Differences in tooth morphology can also be correlated with characteristics of the marks left by the teeth. In a study of tooth marks on dinosaur bones from the Dinosaur Park Formation of Alberta, Canada, it was possible to identify the feeding theropods to family, generic...... different taxa and different skeletal elements produced some interesting results. The frequency of tooth marked dinosaur bones is higher than expected. Up to 14 % of the observed hadrosaur bones were predator damaged. The lower incidence of damage in ceratopsian bones can be explained by the fact...

  4. Walking the walk while thinking about the talk: embodied interpretation of metaphorical narratives.

    Science.gov (United States)

    Gibbs, Raymond W

    2013-08-01

    Two sets of experiments examined people's embodied understanding of metaphorical narratives. Participants heard one of two stories about a romantic relationship; either one that was successful or one that was not, that initially described it in metaphorical terms as "Your relationship was moving along in a good direction" or nonmetaphorical terms as "Your relationship was very important to you." Participants were then blindfolded and attempted to accurately walk, or imagine walking, to a marker 40 feet away while they thought about the story they just heard. People who heard about the successful metaphorical story walked longer and further than those presented with the unsuccessful relationship story. But these walking and imagining differences disappeared when the critical metaphorical statement "moving along in a good direction" was replaced by a nonmetaphorical expression. These findings, and those from another set of experiments, suggest that people's understanding of metaphorical narratives is partly based on their embodied simulations of the metaphorical actions referred to in these stories.

  5. Using step width to compare locomotor biomechanics between extinct, non-avian theropod dinosaurs and modern obligate bipeds.

    Science.gov (United States)

    Bishop, P J; Clemente, C J; Weems, R E; Graham, D F; Lamas, L P; Hutchinson, J R; Rubenson, J; Wilson, R S; Hocknull, S A; Barrett, R S; Lloyd, D G

    2017-07-01

    How extinct, non-avian theropod dinosaurs locomoted is a subject of considerable interest, as is the manner in which it evolved on the line leading to birds. Fossil footprints provide the most direct evidence for answering these questions. In this study, step width-the mediolateral (transverse) distance between successive footfalls-was investigated with respect to speed (stride length) in non-avian theropod trackways of Late Triassic age. Comparable kinematic data were also collected for humans and 11 species of ground-dwelling birds. Permutation tests of the slope on a plot of step width against stride length showed that step width decreased continuously with increasing speed in the extinct theropods ( p < 0.001), as well as the five tallest bird species studied ( p < 0.01). Humans, by contrast, showed an abrupt decrease in step width at the walk-run transition. In the modern bipeds, these patterns reflect the use of either a discontinuous locomotor repertoire, characterized by distinct gaits (humans), or a continuous locomotor repertoire, where walking smoothly transitions into running (birds). The non-avian theropods are consequently inferred to have had a continuous locomotor repertoire, possibly including grounded running. Thus, features that characterize avian terrestrial locomotion had begun to evolve early in theropod history. © 2017 The Author(s).

  6. An enigmatic plant-eating theropod from the Late Jurassic period of Chile.

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    Novas, Fernando E; Salgado, Leonardo; Suárez, Manuel; Agnolín, Federico L; Ezcurra, Martín D; Chimento, Nicolás R; de la Cruz, Rita; Isasi, Marcelo P; Vargas, Alexander O; Rubilar-Rogers, David

    2015-06-18

    Theropod dinosaurs were the dominant predators in most Mesozoic era terrestrial ecosystems. Early theropod evolution is currently interpreted as the diversification of various carnivorous and cursorial taxa, whereas the acquisition of herbivorism, together with the secondary loss of cursorial adaptations, occurred much later among advanced coelurosaurian theropods. A new, bizarre herbivorous basal tetanuran from the Upper Jurassic of Chile challenges this conception. The new dinosaur was discovered at Aysén, a fossil locality in the Upper Jurassic Toqui Formation of southern Chile (General Carrera Lake). The site yielded abundant and exquisitely preserved three-dimensional skeletons of small archosaurs. Several articulated individuals of Chilesaurus at different ontogenetic stages have been collected, as well as less abundant basal crocodyliforms, and fragmentary remains of sauropod dinosaurs (diplodocids and titanosaurians).

  7. Scaling in Theropod Dinosaurs: Femoral Bone Dimensions

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    Lee, Scott A.

    2014-01-01

    Finding topics that inspire students is an important aspect of any physics course. Virtually everyone is fascinated by "Tyrannosaurus rex," and the excitement of the class is palpable when we explore scaling effects in "T. rex" and other bipedal theropod dinosaurs as part of our discussion of mechanics and elasticity. In this…

  8. Homologies and homeotic transformation of the theropod 'semilunate' carpal.

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    Xu, Xing; Han, Fenglu; Zhao, Qi

    2014-08-13

    The homology of the 'semilunate' carpal, an important structure linking non-avian and avian dinosaurs, has been controversial. Here we describe the morphology of some theropod wrists, demonstrating that the 'semilunate' carpal is not formed by the same carpal elements in all theropods possessing this feature and that the involvement of the lateralmost distal carpal in forming the 'semilunate' carpal of birds is an inheritance from their non-avian theropod ancestors. Optimization of relevant morphological features indicates that these features evolved in an incremental way and the 'semilunate' structure underwent a lateral shift in position during theropod evolution, possibly as a result of selection for foldable wings in birds and their close theropod relatives. We propose that homeotic transformation was involved in the evolution of the 'semilunate' carpal. In combination with developmental data on avian wing digits, this suggests that homeosis played a significant role in theropod hand evolution in general.

  9. A king-sized theropod coprolite

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    Chin, K.; Tokaryk, T.T.; Erickson, G.M.; Calk, L.C.

    1998-01-01

    Fossil faeces (coprolites) provide unique trophic perspectives on ancient ecosystems. Yet, although thousands of coprolites have been discovered, specimens that can be unequivocally attributed to carnivorous dinosaurs are almost unknown. A few fossil faeces have been ascribed to herbivorous dinosaurs, but it is more difficult to identify coprolites produced by theropods because other carnivorous taxa coexisted with dinosaurs and most faeces are taxonomically ambiguous. Thus sizeable (up to 20 cm long and 10 cm wide) phosphatic coprolites from Belgium and India that have been attributed to dinosaurs might have been produced by contemporaneous crocodylians or fish. But there is no ambiguity about the theropod origin of the Cretaceous coprolite we report here. This specimen is more than twice as large as any previously reported carnivore coprolite, and its great size and temporal and geographic context indicate that it was produced by a tyrannosaur, most likely Tyrannosaurus rex. The specimen contains a high proportion (30-50%) of bone fragments, an it rare tangible evidence of theropod diet and digestive processes.

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

    Science.gov (United States)

    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…

  11. Tooth-marked small theropod bone: an extremely rare trace

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2001-01-01

    Tooth-marked dinosaur bones provide insight into feeding behaviours and biting strategies of theropod dinosaurs. The majority of theropod tooth marks reported to date have been found on herbivorous dinosaur bones, although some tyrannosaurid bones with tooth marks have also been reported. In 1988...

  12. LIDAR-based characterization and conservation of the first theropod dinosaur trackways from Arkansas, USA.

    Directory of Open Access Journals (Sweden)

    Brian F Platt

    Full Text Available LIDAR-based analyses of the first theropod dinosaur trackways known from the state of Arkansas, USA are reported. The trackways were found on a limestone bedding plane in the Albian De Queen Formation in an active gypsum quarry. Because limited access precluded thorough field study, fieldwork focused on preserving the entire site digitally with ground-based LIDAR, and detailed measurements were later taken digitally from point cloud data. The site contains eight tridactyl trackways associated with sauropod trackways and numerous isolated tracks. Although there appear to be two different tridactyl morphotypes, we show that the tracks are all likely from a single species of trackmaker. We apply a simple method of estimating substrate consistency by comparing the differences between true track dimensions and apparent track dimensions. The tridactyl tracks at the southern end of the site are preserved with significantly greater differences in true vs. apparent dimensions and are shallower than the rest of the tridactyl tracks at the site, which we interpret as the result of outward expansion of the soft tissues of the foot upon contact with a firm substrate. We interpret the firm substrate as having high bulk density and high shear strength, which also explain associated manus-only sauropod tracks. We show that the tridactyl tracks are likely from theropod trackmakers and that footprint lengths, trackway paces, stride lengths, and pace angulations of the De Queen trackways are statistically indistinguishable from equivalent measurements of theropod trackways in the Glen Rose Formation. The Glen Rose tracks are attributed to the large-bodied theropod, Acrocanthosaurus and we likewise attribute the De Queen tracks to Acrocanthosaurus, which is known from skeletal remains in temporally equivalent units and from the mine itself.

  13. LIDAR-based characterization and conservation of the first theropod dinosaur trackways from Arkansas, USA.

    Science.gov (United States)

    Platt, Brian F; Suarez, Celina A; Boss, Stephen K; Williamson, Malcolm; Cothren, Jackson; Kvamme, Jo Ann C

    2018-01-01

    LIDAR-based analyses of the first theropod dinosaur trackways known from the state of Arkansas, USA are reported. The trackways were found on a limestone bedding plane in the Albian De Queen Formation in an active gypsum quarry. Because limited access precluded thorough field study, fieldwork focused on preserving the entire site digitally with ground-based LIDAR, and detailed measurements were later taken digitally from point cloud data. The site contains eight tridactyl trackways associated with sauropod trackways and numerous isolated tracks. Although there appear to be two different tridactyl morphotypes, we show that the tracks are all likely from a single species of trackmaker. We apply a simple method of estimating substrate consistency by comparing the differences between true track dimensions and apparent track dimensions. The tridactyl tracks at the southern end of the site are preserved with significantly greater differences in true vs. apparent dimensions and are shallower than the rest of the tridactyl tracks at the site, which we interpret as the result of outward expansion of the soft tissues of the foot upon contact with a firm substrate. We interpret the firm substrate as having high bulk density and high shear strength, which also explain associated manus-only sauropod tracks. We show that the tridactyl tracks are likely from theropod trackmakers and that footprint lengths, trackway paces, stride lengths, and pace angulations of the De Queen trackways are statistically indistinguishable from equivalent measurements of theropod trackways in the Glen Rose Formation. The Glen Rose tracks are attributed to the large-bodied theropod, Acrocanthosaurus and we likewise attribute the De Queen tracks to Acrocanthosaurus, which is known from skeletal remains in temporally equivalent units and from the mine itself.

  14. Interpretations

    Science.gov (United States)

    Bellac, Michel Le

    2014-11-01

    Although nobody can question the practical efficiency of quantum mechanics, there remains the serious question of its interpretation. As Valerio Scarani puts it, "We do not feel at ease with the indistinguishability principle (that is, the superposition principle) and some of its consequences." Indeed, this principle which pervades the quantum world is in stark contradiction with our everyday experience. From the very beginning of quantum mechanics, a number of physicists--but not the majority of them!--have asked the question of its "interpretation". One may simply deny that there is a problem: according to proponents of the minimalist interpretation, quantum mechanics is self-sufficient and needs no interpretation. The point of view held by a majority of physicists, that of the Copenhagen interpretation, will be examined in Section 10.1. The crux of the problem lies in the status of the state vector introduced in the preceding chapter to describe a quantum system, which is no more than a symbolic representation for the Copenhagen school of thought. Conversely, one may try to attribute some "external reality" to this state vector, that is, a correspondence between the mathematical description and the physical reality. In this latter case, it is the measurement problem which is brought to the fore. In 1932, von Neumann was first to propose a global approach, in an attempt to build a purely quantum theory of measurement examined in Section 10.2. This theory still underlies modern approaches, among them those grounded on decoherence theory, or on the macroscopic character of the measuring apparatus: see Section 10.3. Finally, there are non-standard interpretations such as Everett's many worlds theory or the hidden variables theory of de Broglie and Bohm (Section 10.4). Note, however, that this variety of interpretations has no bearing whatsoever on the practical use of quantum mechanics. There is no controversy on the way we should use quantum mechanics!

  15. Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany.

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    Gerke, Oliver; Wings, Oliver

    2016-01-01

    Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A-R) could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A) and Abelisauridae (morphotype K). This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q) differ only in some probably size-related characteristics from larger morphotypes (B and C) and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America.

  16. Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany.

    Directory of Open Access Journals (Sweden)

    Oliver Gerke

    Full Text Available Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A-R could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A and Abelisauridae (morphotype K. This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q differ only in some probably size-related characteristics from larger morphotypes (B and C and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America.

  17. Estimating cranial musculoskeletal constraints in theropod dinosaurs.

    Science.gov (United States)

    Lautenschlager, Stephan

    2015-11-01

    Many inferences on the biology, behaviour and ecology of extinct vertebrates are based on the reconstruction of the musculature and rely considerably on its accuracy. Although the advent of digital reconstruction techniques has facilitated the creation and testing of musculoskeletal hypotheses in recent years, muscle strain capabilities have rarely been considered. Here, a digital modelling approach using the freely available visualization and animation software Blender is applied to estimate cranial muscle length changes and optimal and maximal possible gape in different theropod dinosaurs. Models of living archosaur taxa (Alligator mississippiensis, Buteo buteo) were used in an extant phylogenetically bracketed framework to validate the method. Results of this study demonstrate that Tyrannosaurus rex, Allosaurus fragilis and Erlikosaurus andrewsi show distinct differences in the recruitment of the jaw adductor musculature and resulting gape, confirming previous dietary and ecological assumptions. While the carnivorous taxa T. rex and Allo. fragilis were capable of a wide gape and sustained muscle force, the herbivorous therizinosaurian E. andrewsi was constrained to small gape angles.

  18. The evolutionary continuum of limb function from early theropods to birds.

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    Hutchinson, John R; Allen, Vivian

    2009-04-01

    The bipedal stance and gait of theropod dinosaurs evolved gradually along the lineage leading to birds and at some point(s), flight evolved. How and when did these changes occur? We review the evidence from neontology and paleontology, including pectoral and pelvic limb functional morphology, fossil footprints/trackways and biomechanical models and simulations. We emphasise that many false dichotomies or categories have been applied to theropod form and function, and sometimes, these impede research progress. For example, dichotomisation of locomotor function into 'non-avian' and 'avian' modes is only a conceptual crutch; the evidence supports a continuous transition. Simplification of pelvic limb function into cursorial/non-cursorial morphologies or flexed/columnar poses has outlived its utility. For the pectoral limbs, even the classic predatory strike vs. flight wing-stroke distinction and separation of theropods into non-flying and flying--or terrestrial and arboreal--categories may be missing important subtleties. Distinguishing locomotor function between taxa, even with quantitative approaches, will always be fraught with ambiguity, making it difficult to find real differences if that ambiguity is properly acknowledged. There must be an 'interpretive asymptote' for reconstructing dinosaur limb function that available methods and evidence cannot overcome. We may be close to that limit, but how far can it be stretched with improved methods and evidence, if at all? The way forward is a combination of techniques that emphasises integration of neontological and paleontological evidence and quantitative assessment of limb function cautiously applied with validated techniques and sensitivity analysis of unknown variables.

  19. The influence of speed and size on avian terrestrial locomotor biomechanics: Predicting locomotion in extinct theropod dinosaurs.

    Science.gov (United States)

    Bishop, P J; Graham, D F; Lamas, L P; Hutchinson, J R; Rubenson, J; Hancock, J A; Wilson, R S; Hocknull, S A; Barrett, R S; Lloyd, D G; Clemente, C J

    2018-01-01

    How extinct, non-avian theropod dinosaurs moved is a subject of considerable interest and controversy. A better understanding of non-avian theropod locomotion can be achieved by better understanding terrestrial locomotor biomechanics in their modern descendants, birds. Despite much research on the subject, avian terrestrial locomotion remains little explored in regards to how kinematic and kinetic factors vary together with speed and body size. Here, terrestrial locomotion was investigated in twelve species of ground-dwelling bird, spanning a 1,780-fold range in body mass, across almost their entire speed range. Particular attention was devoted to the ground reaction force (GRF), the force that the feet exert upon the ground. Comparable data for the only other extant obligate, striding biped, humans, were also collected and studied. In birds, all kinematic and kinetic parameters examined changed continuously with increasing speed, while in humans all but one of those same parameters changed abruptly at the walk-run transition. This result supports previous studies that show birds to have a highly continuous locomotor repertoire compared to humans, where discrete 'walking' and 'running' gaits are not easily distinguished based on kinematic patterns alone. The influences of speed and body size on kinematic and kinetic factors in birds are developed into a set of predictive relationships that may be applied to extinct, non-avian theropods. The resulting predictive model is able to explain 79-93% of the observed variation in kinematics and 69-83% of the observed variation in GRFs, and also performs well in extrapolation tests. However, this study also found that the location of the whole-body centre of mass may exert an important influence on the nature of the GRF, and hence some caution is warranted, in lieu of further investigation.

  20. The influence of speed and size on avian terrestrial locomotor biomechanics: Predicting locomotion in extinct theropod dinosaurs.

    Directory of Open Access Journals (Sweden)

    P J Bishop

    Full Text Available How extinct, non-avian theropod dinosaurs moved is a subject of considerable interest and controversy. A better understanding of non-avian theropod locomotion can be achieved by better understanding terrestrial locomotor biomechanics in their modern descendants, birds. Despite much research on the subject, avian terrestrial locomotion remains little explored in regards to how kinematic and kinetic factors vary together with speed and body size. Here, terrestrial locomotion was investigated in twelve species of ground-dwelling bird, spanning a 1,780-fold range in body mass, across almost their entire speed range. Particular attention was devoted to the ground reaction force (GRF, the force that the feet exert upon the ground. Comparable data for the only other extant obligate, striding biped, humans, were also collected and studied. In birds, all kinematic and kinetic parameters examined changed continuously with increasing speed, while in humans all but one of those same parameters changed abruptly at the walk-run transition. This result supports previous studies that show birds to have a highly continuous locomotor repertoire compared to humans, where discrete 'walking' and 'running' gaits are not easily distinguished based on kinematic patterns alone. The influences of speed and body size on kinematic and kinetic factors in birds are developed into a set of predictive relationships that may be applied to extinct, non-avian theropods. The resulting predictive model is able to explain 79-93% of the observed variation in kinematics and 69-83% of the observed variation in GRFs, and also performs well in extrapolation tests. However, this study also found that the location of the whole-body centre of mass may exert an important influence on the nature of the GRF, and hence some caution is warranted, in lieu of further investigation.

  1. The tail of Tyrannosaurus: reassessing the size and locomotive importance of the M. caudofemoralis in non-avian theropods.

    Science.gov (United States)

    Persons, W Scott; Currie, Philip J

    2011-01-01

    Unlike extant birds and mammals, most non-avian theropods had large muscular tails, with muscle arrangements similar to those of modern reptiles. Examination of ornithomimid and tyrannosaurid tails revealed sequential diagonal scarring on the lateral faces of four or more hemal spines that consistently correlates with the zone of the tail just anterior to the disappearance of the vertebral transverse processes. This sequential scarring is interpreted as the tapering boundary between the insertions of the M. caudofemoralis and the M. ilioischiocaudalis. Digital muscle reconstructions based on measurements of fossil specimens and dissections of modern reptiles showed that the M. caudofemoralis of many non-avian theropods was exceptionally large. These high caudofemoral mass estimates are consistent with the elevation of the transverse processes of the caudal vertebra above the centrum, which creates an enlarged hypaxial region. Dorsally elevated transverse processes are characteristic of even primitive theropods and suggest that a large M. caudofemoralis is a basal characteristic of the group. In the genus Tyrannosaurus, the mass of the M. caudofemoralis was further increased by dorsoventrally lengthening the hemal arches. The expanded M. caudofemoralis of Tyrannosaurus may have evolved as compensation for the animal's immense size. Because the M. caudofemoralis is the primary hind limb retractor, large M. caudofemoralis masses and the resulting contractile force and torque estimates presented here indicate a sizable investment in locomotive muscle among theropods with a range of body sizes and give new evidence in favor of greater athleticism, in terms of overall cursoriality, balance, and turning agility. 2010 Wiley-Liss, Inc.

  2. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion

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    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…

  3. Body Size as a Driver of Scavenging in Theropod Dinosaurs.

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    Kane, Adam; Healy, Kevin; Ruxton, Graeme D; Jackson, Andrew L

    2016-06-01

    Theropod dinosaurs dominated Earth's terrestrial ecosystem as a diverse group of predators for more than 160 million years, yet little is known about their foraging ecology. Maintaining a balanced energy budget presented a major challenge for therapods, which ranged from the chicken-sized Microraptor up to the whale-sized Giganotosaurus, in the face of intense competition and the demands of ontogenetic growth. Facultative scavenging, a behavior present in almost all modern predators, may have been important in supplementing energetically expensive lifestyles. By using agent-based models based on the allometric relationship between size and foraging behaviors, we show that theropods between 27 and 1,044 kg would have gained a significant energetic advantage over individuals at both the small and large extremes of theropod body mass through their scavenging efficiency. These results were robust to rate of competition, primary productivity, and detection distance. Our models demonstrate the potential importance of facultative scavenging in theropods and the role of body size in defining its prevalence in Mesozoic terrestrial systems.

  4. The evolution of cranial form and function in theropod dinosaurs:Insights from geometric morphometrics

    OpenAIRE

    Brusatte, S.L.; Montanari, S.; Harcourt Smith, W.E.H.; Sakamoto, M.

    2012-01-01

    Theropod dinosaurs, an iconic clade of fossil species including Tyrannosaurus and Velociraptor, developed a great diversity of body size, skull form and feeding habits over their 160+ million year evolutionary history. Here, we utilize geometric morphometrics to study broad patterns in theropod skull shape variation and compare the distribution of taxa in cranial morphospace (form) to both phylogeny and quantitative metrics of biting behaviour (function). We find that theropod skulls primaril...

  5. The phylogenetic position of the Tyrannosauridae: implications for theropod systematics

    Science.gov (United States)

    Holtz, T.R.

    1994-01-01

    A new cladistic analysis indicates that the tyrannosaurs were derived members of the Coelurosauria, a group of otherwise small theropods. Desipte certain gross cranial similarities with the large predators of the Jurassic and Early Cretaceous, the Late Cretaceous tyrannosaurids are shown to be the sister group to ornithominids and troodontids, which share a derived condition of the metatarsus. The taxa "Carnosauria' and "Deinonychosauria' are shown to be polyphyletic, and the Late Jurassic African form Elaphrosaurus is found to be the sister taxon to Abelisauridae. Purported allosaurid-tyrannosaurid synapomorphies are seen to be largely size-related. The remaining giant tetanurine theropods were found to be progressive distant outgroups to an allosaurid-coelurosaur clade. -from Author

  6. Vertebral Adaptations to Large Body Size in Theropod Dinosaurs.

    Directory of Open Access Journals (Sweden)

    John P Wilson

    Full Text Available Rugose projections on the anterior and posterior aspects of vertebral neural spines appear throughout Amniota and result from the mineralization of the supraspinous and interspinous ligaments via metaplasia, the process of permanent tissue-type transformation. In mammals, this metaplasia is generally pathological or stress induced, but is a normal part of development in some clades of birds. Such structures, though phylogenetically sporadic, appear throughout the fossil record of non-avian theropod dinosaurs, yet their physiological and adaptive significance has remained unexamined. Here we show novel histologic and phylogenetic evidence that neural spine projections were a physiological response to biomechanical stress in large-bodied theropod species. Metaplastic projections also appear to vary between immature and mature individuals of the same species, with immature animals either lacking them or exhibiting smaller projections, supporting the hypothesis that these structures develop through ontogeny as a result of increasing bending stress subjected to the spinal column. Metaplastic mineralization of spinal ligaments would likely affect the flexibility of the spinal column, increasing passive support for body weight. A stiff spinal column would also provide biomechanical support for the primary hip flexors and, therefore, may have played a role in locomotor efficiency and mobility in large-bodied species. This new association of interspinal ligament metaplasia in Theropoda with large body size contributes additional insight to our understanding of the diverse biomechanical coping mechanisms developed throughout Dinosauria, and stresses the significance of phylogenetic methods when testing for biological trends, evolutionary or not.

  7. Vertebral Adaptations to Large Body Size in Theropod Dinosaurs.

    Science.gov (United States)

    Wilson, John P; Woodruff, D Cary; Gardner, Jacob D; Flora, Holley M; Horner, John R; Organ, Chris L

    2016-01-01

    Rugose projections on the anterior and posterior aspects of vertebral neural spines appear throughout Amniota and result from the mineralization of the supraspinous and interspinous ligaments via metaplasia, the process of permanent tissue-type transformation. In mammals, this metaplasia is generally pathological or stress induced, but is a normal part of development in some clades of birds. Such structures, though phylogenetically sporadic, appear throughout the fossil record of non-avian theropod dinosaurs, yet their physiological and adaptive significance has remained unexamined. Here we show novel histologic and phylogenetic evidence that neural spine projections were a physiological response to biomechanical stress in large-bodied theropod species. Metaplastic projections also appear to vary between immature and mature individuals of the same species, with immature animals either lacking them or exhibiting smaller projections, supporting the hypothesis that these structures develop through ontogeny as a result of increasing bending stress subjected to the spinal column. Metaplastic mineralization of spinal ligaments would likely affect the flexibility of the spinal column, increasing passive support for body weight. A stiff spinal column would also provide biomechanical support for the primary hip flexors and, therefore, may have played a role in locomotor efficiency and mobility in large-bodied species. This new association of interspinal ligament metaplasia in Theropoda with large body size contributes additional insight to our understanding of the diverse biomechanical coping mechanisms developed throughout Dinosauria, and stresses the significance of phylogenetic methods when testing for biological trends, evolutionary or not.

  8. The first well-preserved coelophysoid theropod dinosaur from Asia.

    Science.gov (United States)

    You, Hai-Lu; Azuma, Yoichi; Wang, Tao; Wang, Ya-Ming; Dong, Zhi-Ming

    2014-10-16

    Coelophysoid dinosaurs represent the earliest major radiation of neotheropods. These small-to-medium-sized agile bipeds lived throughout much of Pangaea during the Late Triassic-arly Jurassic. Previously reported coelophysoid material from Asia (excluding the Gondwanan territory of India) is limited to two specimens that comprise only limb fragments. This paper describes a new genus and species of coelophysoid, Panguraptor lufengensis, from the Lower Jurassic Lufeng Formation of Yunnan Province, China. The new taxon is represented by a well-preserved skeleton, including the skull and lower jaw, the presacral vertebral column and partial ribs, the right scapula, a partial forelimb, part of the pelvic girdle, and an almost complete hind limb. It is distinguished from other coelophysoid theropods by the unique combination of the following three character states: 1) diagonal (rostrodorsal-caudoventral) ridge on lateral surface of maxilla, within antorbital fossa, 2) elliptical, laterally facing fenestra caudodorsal to aforementioned diagonal ridge, and 3) hooked craniomedial corner of distal tarsal IV. Cladistic analysis recovers Panguraptor lufengensis deeply nested within Coelophysoidea as a member of Coelophysidae, and it is more closely related to Coelophysis than to "Syntarsus". Panguraptor represents the first well-preserved coelophysoid theropod dinosaur from Asia, and provides fresh evidence supporting the hypothesis that terrestrial tetrapods tended to be distributed pan-continentally during the Early Jurassic.

  9. Bird-like anatomy, posture, and behavior revealed by an early jurassic theropod dinosaur resting trace.

    Directory of Open Access Journals (Sweden)

    Andrew R C Milner

    Full Text Available BACKGROUND: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe a well-preserved theropod trackway in a Lower Jurassic ( approximately 198 million-year-old lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. CONCLUSIONS/SIGNIFICANCE: The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.

  10. Bird-like anatomy, posture, and behavior revealed by an early jurassic theropod dinosaur resting trace

    Science.gov (United States)

    Milner, Andrew R.C.; Harris, J.D.; Lockley, M.G.; Kirkland, J.I.; Matthews, N.A.

    2009-01-01

    Background: Fossil tracks made by non-avian theropod dinosaurs commonly reflect the habitual bipedal stance retained in living birds. Only rarely-captured behaviors, such as crouching, might create impressions made by the hands. Such tracks provide valuable information concerning the often poorly understood functional morphology of the early theropod forelimb. Methodology/Principal Findings: Here we describe a well-preserved theropod trackway in a Lower Jurassic (???198 millionyear- old) lacustrine beach sandstone in the Whitmore Point Member of the Moenave Formation in southwestern Utah. The trackway consists of prints of typical morphology, intermittent tail drags and, unusually, traces made by the animal resting on the substrate in a posture very similar to modern birds. The resting trace includes symmetrical pes impressions and well-defined impressions made by both hands, the tail, and the ischial callosity. Conclusions/Significance: The manus impressions corroborate that early theropods, like later birds, held their palms facing medially, in contrast to manus prints previously attributed to theropods that have forward-pointing digits. Both the symmetrical resting posture and the medially-facing palms therefore evolved by the Early Jurassic, much earlier in the theropod lineage than previously recognized, and may characterize all theropods.

  11. Feeding strategies as revealed by the section moduli of the humerus bones in bipedal theropod dinosaurs

    Science.gov (United States)

    Lee, Scott; Richards, Zachary

    2015-03-01

    The section modulus of a bone is a measure of its ability to resist bending torques. Carnivorous dinosaurs presumably had strong arm bones to hold struggling prey during hunting. Some theropods are believed to have become herbivorous and such animals would not have needed such strong arms. In this work, the section moduli of the humerus bones of bipedal theropod dinosaurs (from Microvenator celer to Tyrannosaurus rex) are studied to determine the maximum bending loads their arms could withstand. The results show that bending strength is not of uniform importance to these magnificent animals. The predatory theropods had strong arms for use in hunting. In contrast, the herbivorous dinosaurs had weaker arms.

  12. A reassessment of Kelmayisaurus petrolicus, a large theropod dinosaur from the Early Cretaceous of China

    OpenAIRE

    Brusatte, S.L.; Benson, R.B.J.; Xu, X.

    2012-01-01

    The Early Cretaceous fossil record of large−bodied theropods from Asia is poor, hindering comparison of Asian predatory dinosaur faunas with those from other continents. One of the few large Asian theropod specimens from this interval is a partial skull (maxilla and dentary) from the Lianmugin Formation (?Valanginian–Albian), the holotype of Kelmayisaurus petrolicus. Most authors have either considered this specimen as an indeterminate basal tetanuran or a nomen dubium. Weredescribe K. petrol...

  13. Evolution of the respiratory system in nonavian theropods: evidence from rib and vertebral morphology.

    Science.gov (United States)

    Schachner, Emma R; Lyson, Tyler R; Dodson, Peter

    2009-09-01

    Recent reports of region-specific vertebral pneumaticity in nonavian theropod dinosaurs have brought attention to the hypothesis that these animals possessed an avian-style respiratory system with flow-through ventilation. This study explores the thoracic rib and vertebral anatomy of Sinraptor, Allosaurus, Tyrannosaurus, and Deinonychus; four nonavian theropods that all show well-preserved thoracic vertebrae and ribs. Comparisons to the osteology and soft tissue anatomy of extant saurians provide new evidence supporting the hypothesis of flow-through ventilation in nonavian theropods. Analyses of diapophyseal and parapophyseal position and thoracic rib morphology suggest that most nonavian theropods possessed lungs that were deeply incised by the adjacent bicapitate thoracic ribs. This functionally constrains the lungs as rigid nonexpansive organs that were likely ventilated by accessory nonvascularized air sacs. The axial anatomy of this group also reveals that a crocodilian-like hepatic-piston lung would be functionally and biomechanically untenable. Taken together with the evidence that avian-like air sacs were present in basal theropods, these data lead us to conclude that an avian-style pulmonary system was likely a universal theropod trait. (c) 2009 Wiley-Liss, Inc.

  14. Megalosauripus transjuranicus ichnosp. nov. A new Late Jurassic theropod ichnotaxon from NW Switzerland and implications for tridactyl dinosaur ichnology and ichnotaxomy.

    Science.gov (United States)

    Razzolini, Novella L; Belvedere, Matteo; Marty, Daniel; Paratte, Géraldine; Lovis, Christel; Cattin, Marielle; Meyer, Christian A

    2017-01-01

    long trackways very consistently present Morphotype II features (notably blunt digits) and do not exhibit any of the features that are typical for Megalosauripus (notably phalangeal pads). Therefore, it is not very likely that these tracks are preservational variants of Megalosauripus transjuranicus or Megalosauripus isp. These trackways are interpreted to have been left by an ornithopod dinosaur. The high frequency of large theropod tracks in tidal-flat deposits of the Jura carbonate platform, associated on single ichnoassemblages with minute to medium-sized tridactyl and tiny to large sauropod tracks has important implications for the dinosaur community and for paleoenvironmental and paleogeographical reconstructions. As with most other known occurrences of Megalosauripus tracks, M. transjuranicus is found in coastal settings, which may reflect the preference of their theropod trackmakers for expanded carbonate flats where food was abundant.

  15. A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America.

    Directory of Open Access Journals (Sweden)

    Lindsay E Zanno

    Full Text Available Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species--Troodon formosus--presently known from substantial skeletal remains.Here we report a gracile new troodontid theropod--Talos sampsoni gen. et sp. nov.--from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes.Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and

  16. The evolution of cranial form and function in theropod dinosaurs: insights from geometric morphometrics.

    Science.gov (United States)

    Brusatte, S L; Sakamoto, M; Montanari, S; Harcourt Smith, W E H

    2012-02-01

    Theropod dinosaurs, an iconic clade of fossil species including Tyrannosaurus and Velociraptor, developed a great diversity of body size, skull form and feeding habits over their 160+ million year evolutionary history. Here, we utilize geometric morphometrics to study broad patterns in theropod skull shape variation and compare the distribution of taxa in cranial morphospace (form) to both phylogeny and quantitative metrics of biting behaviour (function). We find that theropod skulls primarily differ in relative anteroposterior length and snout depth and to a lesser extent in orbit size and depth of the cheek region, and oviraptorosaurs deviate most strongly from the "typical" and ancestral theropod morphologies. Noncarnivorous taxa generally fall out in distinct regions of morphospace and exhibit greater overall disparity than carnivorous taxa, whereas large-bodied carnivores independently converge on the same region of morphospace. The distribution of taxa in morphospace is strongly correlated with phylogeny but only weakly correlated with functional biting behaviour. These results imply that phylogeny, not biting function, was the major determinant of theropod skull shape. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

  17. Bony cranial ornamentation linked to rapid evolution of gigantic theropod dinosaurs

    Science.gov (United States)

    Gates, Terry A.; Organ, Chris; Zanno, Lindsay E.

    2016-09-01

    Exaggerated cranial structures such as crests and horns, hereafter referred to collectively as ornaments, are pervasive across animal species. These structures perform vital roles in visual communication and physical interactions within and between species. Yet the origin and influence of ornamentation on speciation and ecology across macroevolutionary time scales remains poorly understood for virtually all animals. Here, we explore correlative evolution of osseous cranial ornaments with large body size in theropod dinosaurs using a phylogenetic comparative framework. We find that body size evolved directionally toward phyletic giantism an order of magnitude faster in theropod species possessing ornaments compared with unadorned lineages. In addition, we find a body mass threshold below which bony cranial ornaments do not originate. Maniraptoriform dinosaurs generally lack osseous cranial ornaments despite repeatedly crossing this body size threshold. Our study provides novel, quantitative support for a shift in selective pressures on socio-sexual display mechanisms in theropods coincident with the evolution of pennaceous feathers.

  18. Developmental and evolutionary novelty in the serrated teeth of theropod dinosaurs.

    Science.gov (United States)

    Brink, K S; Reisz, R R; LeBlanc, A R H; Chang, R S; Lee, Y C; Chiang, C C; Huang, T; Evans, D C

    2015-07-28

    Tooth morphology and development can provide valuable insights into the feeding behaviour and evolution of extinct organisms. The teeth of Theropoda, the only clade of predominantly predatory dinosaurs, are characterized by ziphodonty, the presence of serrations (denticles) on their cutting edges. Known today only in varanid lizards, ziphodonty is much more pervasive in the fossil record. Here we present the first model for the development of ziphodont teeth in theropods through histological, SEM, and SR-FTIR analyses, revealing that structures previously hypothesized to prevent tooth breakage instead first evolved to shape and maintain the characteristic denticles through the life of the tooth. We show that this novel complex of dental morphology and tissues characterizes Theropoda, with the exception of species with modified feeding behaviours, suggesting that these characters are important for facilitating the hypercarnivorous diet of most theropods. This adaptation may have played an important role in the initial radiation and subsequent success of theropods as terrestrial apex predators.

  19. An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina

    Science.gov (United States)

    Apesteguía, Sebastián; Smith, Nathan D.; Juárez Valieri, Rubén; Makovicky, Peter J.

    2016-01-01

    Background Late Cretaceous terrestrial strata of the Neuquén Basin, northern Patagonia, Argentina have yielded a rich fauna of dinosaurs and other vertebrates. The diversity of saurischian dinosaurs is particularly high, especially in the late Cenomanian-early Turonian Huincul Formation, which has yielded specimens of rebacchisaurid and titanosaurian sauropods, and abelisaurid and carcharodontosaurid theropods. Continued sampling is adding to the known vertebrate diversity of this unit. Methodology/ Principal Findings A new, partially articulated mid-sized theropod was found in rocks from the Huincul Formation. It exhibits a unique combination of traits that distinguish it from other known theropods justifying erection of a new taxon, Gualicho shinyae gen. et sp. nov. Gualicho possesses a didactyl manus with the third digit reduced to a metacarpal splint reminiscent of tyrannosaurids, but both phylogenetic and multivariate analyses indicate that didactyly is convergent in these groups. Derived characters of the scapula, femur, and fibula supports the new theropod as the sister taxon of the nearly coeval African theropod Deltadromeus and as a neovenatorid carcharodontosaurian. A number of these features are independently present in ceratosaurs, and Gualicho exhibits an unusual mosaic of ceratosaurian and tetanuran synapomorphies distributed throughout the skeleton. Conclusions/ Significance Gualicho shinyae gen. et sp. nov. increases the known theropod diversity of the Huincul Formation and also represents the first likely neovenatorid from this unit. It is the most basal tetatanuran to exhibit common patterns of digit III reduction that evolved independently in a number of other tetanuran lineages. A close relationship with Deltadromaeus from the Kem Kem beds of Niger adds to the already considerable biogeographic similarity between the Huincul Formation and coeval rock units in North Africa. PMID:27410683

  20. Shake a tail feather: the evolution of the theropod tail into a stiff aerodynamic surface.

    Directory of Open Access Journals (Sweden)

    Michael Pittman

    Full Text Available Theropod dinosaurs show striking morphological and functional tail variation; e.g., a long, robust, basal theropod tail used for counterbalance, or a short, modern avian tail used as an aerodynamic surface. We used a quantitative morphological and functional analysis to reconstruct intervertebral joint stiffness in the tail along the theropod lineage to extant birds. This provides new details of the tail's morphological transformation, and for the first time quantitatively evaluates its biomechanical consequences. We observe that both dorsoventral and lateral joint stiffness decreased along the non-avian theropod lineage (between nodes Theropoda and Paraves. Our results show how the tail structure of non-avian theropods was mechanically appropriate for holding itself up against gravity and maintaining passive balance. However, as dorsoventral and lateral joint stiffness decreased, the tail may have become more effective for dynamically maintaining balance. This supports our hypothesis of a reduction of dorsoventral and lateral joint stiffness in shorter tails. Along the avian theropod lineage (Avialae to crown group birds, dorsoventral and lateral joint stiffness increased overall, which appears to contradict our null expectation. We infer that this departure in joint stiffness is specific to the tail's aerodynamic role and the functional constraints imposed by it. Increased dorsoventral and lateral joint stiffness may have facilitated a gradually improved capacity to lift, depress, and swing the tail. The associated morphological changes should have resulted in a tail capable of producing larger muscular forces to utilise larger lift forces in flight. Improved joint mobility in neornithine birds potentially permitted an increase in the range of lift force vector orientations, which might have improved flight proficiency and manoeuvrability. The tail morphology of modern birds with tail fanning capabilities originated in early ornithuromorph

  1. Secondarily flightless birds or Cretaceous non-avian theropods?

    Science.gov (United States)

    Kavanau, J Lee

    2010-02-01

    Recent studies by Varricchio et al. reveal that males cared for the eggs of troodontids and oviraptorids, so-called "non-avian theropods" of the Cretaceous, just as do those of most Paleognathic birds (ratites and tinamous) today. Further, the clutches of both groups have large relative volumes, and consist of many eggs of relatively large size. By comparison, clutch care by most extant birds is biparental and the clutches are of small relative volume, and consist of but few small eggs. Varricchio et al. propose that troodontids and oviraptorids were pre-avian and that paternal egg care preceded the origin of birds. On the contrary, unmentioned by them is that abundant paleontological evidence has led several workers to conclude that troodontids and oviraptorids were secondary flightless birds. This evidence ranges from bird-like bodies and bone designs, adapted for climbing, perching, gliding, and ultimately flight, to relatively large, highly developed brains, poor sense of smell, and their feeding habits. Because ratites also are secondarily flightless and tinamous are reluctant, clumsy fliers, the new evidence strengthens the view that troodontids and oviraptorids were secondarily flightless. Although secondary flightlessness apparently favors paternal care of clutches of large, abundant eggs, such care is not likely to have been primitive. There are a suite of previously unknown independent findings that point to the evolution of, first, maternal, followed by biparental egg care in earliest ancestors of birds. This follows from the discovery of remarkable relict avian reproductive behaviors preserved by virtue of the highly conservative nature of vertebrate brain evolution. These behaviors can be elicited readily by exposing breeding birds to appropriate conditions, both environmental and with respect to their eggs and chicks. They give significant new clues for a coherent theory of avian origin and early evolution.

  2. The Act of Walking

    DEFF Research Database (Denmark)

    Vestergaard, Maria Quvang Harck; Olesen, Mette; Helmer, Pernille Falborg

    2014-01-01

    perception of ‘walkability’ is based upon a subjective judgement of different physical factors, such as sidewalk width, traffic volumes and building height (Ewing and Handy 2009:67). And iIn order to understand the act of walking it is therefore necessary to create a vocabulary to understand how and why...... the individuals evaluate, interpret and act (Bourdieu 1984), and how this affects their choice to walk. Therefore it could be questioned if whether an assessment of the physical environment is sufficient to identify all the factors that influence the individual perception of ‘walkability’, or if other influencing...... factors like lifestyle and life situation should be addressed in order to understand ‘walkability’ fully. The challenge is to approach issues linked to the ‘more-than representational’ (Thrift 2007; Vannini 2012) act of walking and thereby understand pedestrian behaviour in general, but also...

  3. Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks

    Science.gov (United States)

    Stiegler, Josef; Wu, Ping; Chuong, Cheng-Ming; Hu, Dongyu; Balanoff, Amy; Zhou, Yachun; Xu, Xing

    2017-01-01

    Beaks are innovative structures characterizing numerous tetrapod lineages, including birds, but little is known about how developmental processes influenced the macroevolution of these important structures. Here we provide evidence of ontogenetic vestigialization of alveoli in two lineages of theropod dinosaurs and show that these are transitional phenotypes in the evolution of beaks. One of the smallest known caenagnathid oviraptorosaurs and a small specimen of the Early Cretaceous bird Sapeornis both possess shallow, empty vestiges of dentary alveoli. In both individuals, the system of vestiges connects via foramina with a dorsally closed canal homologous to alveoli. Similar morphologies are present in Limusaurus, a beaked theropod that becomes edentulous during ontogeny; and an analysis of neontological and paleontological evidence shows that ontogenetic reduction of the dentition is a relatively common phenomenon in vertebrate evolution. Based on these lines of evidence, we propose that progressively earlier postnatal and embryonic truncation of odontogenesis corresponds with expansion of rostral keratin associated with the caruncle, and these progenesis and peramorphosis heterochronies combine to drive the evolution of edentulous beaks in nonavian theropods and birds. Following initial apomorphic expansion of rostral keratinized epithelia in perinatal toothed theropods, beaks appear to inhibit odontogenesis as they grow postnatally, resulting in a sequence of common morphologies. This sequence is shifted earlier in development through phylogeny until dentition is absent at hatching, and odontogenesis is inhibited by beak formation in ovo. PMID:28973883

  4. Jaw biomechanics and the evolution of biting performance in theropod dinosaurs

    Science.gov (United States)

    Sakamoto, Manabu

    2010-01-01

    Despite the great diversity in theropod craniomandibular morphology, the presence and distribution of biting function types across Theropoda has rarely been assessed. A novel method of biomechanical profiling using mechanical advantage computed for each biting position along the entirety of the tooth row was applied to 41 extinct theropod taxa. Multivariate ordination on the polynomial coefficients of the profiles reveals the distribution of theropod biting performance in function space. In particular, coelophysoids are found to occupy a unique region of function space, while tetanurans have a wide but continuous function space distribution. Further, the underlying phylogenetic structure and evolution of biting performance were investigated using phylogenetic comparative methods. There is a strong phylogenetic signal in theropod biomechanical profiles, indicating that evolution of biting performance does not depart from Brownian motion evolution. Reconstructions of ancestral function space occupation conform to this pattern, but phylogenetically unexpected major shifts in function space occupation can be observed at the origins of some clades. However, uncertainties surround ancestor estimates in some of these internal nodes, so inferences on the nature of these evolutionary changes must be viewed with caution. PMID:20534620

  5. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs.

    Science.gov (United States)

    Foth, Christian; Rauhut, Oliver W M

    2017-12-02

    Archaeopteryx is an iconic fossil that has long been pivotal for our understanding of the origin of birds. Remains of this important taxon have only been found in the Late Jurassic lithographic limestones of Bavaria, Germany. Twelve skeletal specimens are reported so far. Archaeopteryx was long the only pre-Cretaceous paravian theropod known, but recent discoveries from the Tiaojishan Formation, China, yielded a remarkable diversity of this clade, including the possibly oldest and most basal known clade of avialan, here named Anchiornithidae. However, Archaeopteryx remains the only Jurassic paravian theropod based on diagnostic material reported outside China. Re-examination of the incomplete Haarlem Archaeopteryx specimen did not find any diagnostic features of this genus. In contrast, the specimen markedly differs in proportions from other Archaeopteryx specimens and shares two distinct characters with anchiornithids. Phylogenetic analysis confirms it as the first anchiornithid recorded outside the Tiaojushan Formation of China, for which the new generic name Ostromia is proposed here. In combination with a biogeographic analysis of coelurosaurian theropods and palaeogeographic and stratigraphic data, our results indicate an explosive radiation of maniraptoran coelurosaurs probably in isolation in eastern Asia in the late Middle Jurassic and a rapid, at least Laurasian dispersal of the different subclades in the Late Jurassic. Small body size and, possibly, a multiple origin of flight capabilities enhanced dispersal capabilities of paravian theropods and might thus have been crucial for their evolutionary success.

  6. Femoral bone strength in large theropod dinosaurs: A study by genus

    Science.gov (United States)

    Lee, Scott

    2015-03-01

    The locomotion of bipedal theropod dinosaurs is controlled by the strength of the femur to resist bending torques (caused by the foot striking the ground and the action of muscles on the femur). The section modulus at the narrowest part measures the ability of the femur to resist such torques. We present the results of our study of the femoral section moduli for six genus of large theropods: Tyrannosaurus, Nanotyrannus, Gorgosaurus, and Albertosaurus of the Late Cretaceous, Acrocanthosaurus of the Early Cretaceous, and Allosaurus of the Late Jurassic. These animals had femora of lengths between 65 and 134 cm. The corresponding section moduli varied between 23 and 570 cm3. Some species of Tyrannosaurus, Gorgosaurus, Allosaurus, and Albertosaurus had femora with lengths in the same 75 to 90 cm range. The section moduli of these animals are all in the same range, showing that the animals had the same abilities of locomotion. That is, Allosaurus of the Late Jurassic could locomote just as well as the Late Cretaceous Tyrannosaurus, Gorgosaurus, and Albertosaurus. There is no evidence that these later theropods had evolved to be any faster than similarly-sized theropods living about 80 million years earlier.

  7. Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks.

    Science.gov (United States)

    Wang, Shuo; Stiegler, Josef; Wu, Ping; Chuong, Cheng-Ming; Hu, Dongyu; Balanoff, Amy; Zhou, Yachun; Xu, Xing

    2017-10-10

    Beaks are innovative structures characterizing numerous tetrapod lineages, including birds, but little is known about how developmental processes influenced the macroevolution of these important structures. Here we provide evidence of ontogenetic vestigialization of alveoli in two lineages of theropod dinosaurs and show that these are transitional phenotypes in the evolution of beaks. One of the smallest known caenagnathid oviraptorosaurs and a small specimen of the Early Cretaceous bird Sapeornis both possess shallow, empty vestiges of dentary alveoli. In both individuals, the system of vestiges connects via foramina with a dorsally closed canal homologous to alveoli. Similar morphologies are present in Limusaurus , a beaked theropod that becomes edentulous during ontogeny; and an analysis of neontological and paleontological evidence shows that ontogenetic reduction of the dentition is a relatively common phenomenon in vertebrate evolution. Based on these lines of evidence, we propose that progressively earlier postnatal and embryonic truncation of odontogenesis corresponds with expansion of rostral keratin associated with the caruncle, and these progenesis and peramorphosis heterochronies combine to drive the evolution of edentulous beaks in nonavian theropods and birds. Following initial apomorphic expansion of rostral keratinized epithelia in perinatal toothed theropods, beaks appear to inhibit odontogenesis as they grow postnatally, resulting in a sequence of common morphologies. This sequence is shifted earlier in development through phylogeny until dentition is absent at hatching, and odontogenesis is inhibited by beak formation in ovo .

  8. A late-surviving basal theropod dinosaur from the latest Triassic of North America.

    Science.gov (United States)

    Sues, Hans-Dieter; Nesbitt, Sterling J; Berman, David S; Henrici, Amy C

    2011-11-22

    The oldest theropod dinosaurs are known from the Carnian of Argentina and Brazil. However, the evolutionary diversification of this group after its initial radiation but prior to the Triassic-Jurassic boundary is still poorly understood because of a sparse fossil record near that boundary. Here, we report on a new basal theropod, Daemonosaurus chauliodus gen. et sp. nov., from the latest Triassic 'siltstone member' of the Chinle Formation of the Coelophysis Quarry at Ghost Ranch, New Mexico. Based on a comprehensive phylogenetic analysis, Daemonosaurus is more closely related to coeval neotheropods (e.g. Coelophysis bauri) than to Herrerasauridae and Eoraptor. The skeletal structure of Daemonosaurus and the recently discovered Tawa bridge a morphological gap between Eoraptor and Herrerasauridae on one hand and neotheropods on the other, providing additional support for the theropod affinities of both Eoraptor and Herrerasauridae and demonstrating that lineages from the initial radiation of Dinosauria persisted until the end of the Triassic. Various features of the skull of Daemonosaurus, including the procumbent dentary and premaxillary teeth and greatly enlarged premaxillary and anterior maxillary teeth, clearly set this taxon apart from coeval neotheropods and demonstrate unexpected disparity in cranial shape among theropod dinosaurs just prior to the end of the Triassic.

  9. A large abelisaurid (Dinosauria, Theropoda from Morocco and comments on the Cenomanian theropods from North Africa

    Directory of Open Access Journals (Sweden)

    Alfio Alessandro Chiarenza

    2016-02-01

    Full Text Available We describe the partially preserved femur of a large-bodied theropod dinosaur from the Cenomanian “Kem Kem Compound Assemblage” (KKCA of Morocco. The fossil is housed in the Museo Geologico e Paleontologico “Gaetano Giorgio Gemmellaro” in Palermo (Italy. The specimen is compared with the theropod fossil record from the KKCA and coeval assemblages from North Africa. The combination of a distally reclined head, a not prominent trochanteric shelf, distally placed lesser trochanter of stout, alariform shape, a stocky shaft with the fourth trochanter placed proximally, and rugose muscular insertion areas in the specimen distinguishes it from Carcharodontosaurus, Deltadromeus and Spinosaurus and supports referral to an abelisaurid. The estimated body size for the individual from which this femur was derived is comparable to Carnotaurus and Ekrixinatosaurus (up to 9 meters in length and 2 tons in body mass. This find confirms that abelisaurids had reached their largest body size in the “middle Cretaceous,” and that large abelisaurids coexisted with other giant theropods in Africa. We review the taxonomic status of the theropods from the Cenomanian of North Africa, and provisionally restrict the Linnean binomina Carcharodontosaurus iguidensis and Spinosaurus aegyptiacus to the type specimens. Based on comparisons among the theropod records from the Aptian-Cenomanian of South America and Africa, a partial explanation for the so-called “Stromer’s riddle” (namely, the coexistence of many large predatory dinosaurs in the “middle Cretaceous” record from North Africa is offered in term of taphonomic artifacts among lineage records that were ecologically and environmentally non-overlapping. Although morphofunctional and stratigraphic evidence supports an ecological segregation between spinosaurids and the other lineages, the co-occurrence of abelisaurids and carcharodontosaurids, two groups showing several craniodental convergences that

  10. Walking Problems

    Science.gov (United States)

    ... your legs or feet Movement disorders such as Parkinson's disease Diseases such as arthritis or multiple sclerosis Vision or balance problems Treatment of walking problems depends on the cause. Physical therapy, surgery, or mobility aids may help.

  11. Quantum walks and search algorithms

    CERN Document Server

    Portugal, Renato

    2013-01-01

    This book addresses an interesting area of quantum computation called quantum walks, which play an important role in building quantum algorithms, in particular search algorithms. Quantum walks are the quantum analogue of classical random walks. It is known that quantum computers have great power for searching unsorted databases. This power extends to many kinds of searches, particularly to the problem of finding a specific location in a spatial layout, which can be modeled by a graph. The goal is to find a specific node knowing that the particle uses the edges to jump from one node to the next. This book is self-contained with main topics that include: Grover's algorithm, describing its geometrical interpretation and evolution by means of the spectral decomposition of the evolution operater Analytical solutions of quantum walks on important graphs like line, cycles, two-dimensional lattices, and hypercubes using Fourier transforms Quantum walks on generic graphs, describing methods to calculate the limiting d...

  12. Random walk polynomials and random walk measures

    NARCIS (Netherlands)

    van Doorn, Erik A.; Schrijner, Pauline

    1993-01-01

    Random walk polynomials and random walk measures play a prominent role in the analysis of a class of Markov chains called random walks. Without any reference to random walks, however, a random walk polynomial sequence can be defined (and will be defined in this paper) as a polynomial sequence{Pn(x)}

  13. Multivariate analyses of small theropod dinosaur teeth and implications for paleoecological turnover through time.

    Directory of Open Access Journals (Sweden)

    Derek W Larson

    Full Text Available Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian. It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth

  14. A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America

    OpenAIRE

    Lamanna, Matthew C.; Sues, Hans-Dieter; Schachner, Emma R.; Lyson, Tyler R.

    2014-01-01

    The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosau...

  15. Theropod fauna from southern Australia indicates high polar diversity and climate-driven dinosaur provinciality.

    Science.gov (United States)

    Benson, Roger B J; Rich, Thomas H; Vickers-Rich, Patricia; Hall, Mike

    2012-01-01

    The Early Cretaceous fauna of Victoria, Australia, provides unique data on the composition of high latitude southern hemisphere dinosaurs. We describe and review theropod dinosaur postcranial remains from the Aptian-Albian Otway and Strzelecki groups, based on at least 37 isolated bones, and more than 90 teeth from the Flat Rocks locality. Several specimens of medium- and large-bodied individuals (estimated up to ~8.5 metres long) represent allosauroids. Tyrannosauroids are represented by elements indicating medium body sizes (~3 metres long), likely including the holotype femur of Timimus hermani, and a single cervical vertebra represents a juvenile spinosaurid. Single specimens representing medium- and small-bodied theropods may be referrable to Ceratosauria, Ornithomimosauria, a basal coelurosaur, and at least three taxa within Maniraptora. Thus, nine theropod taxa may have been present. Alternatively, four distinct dorsal vertebrae indicate a minimum of four taxa. However, because most taxa are known from single bones, it is likely that small-bodied theropod diversity remains underestimated. The high abundance of allosauroids and basal coelurosaurs (including tyrannosauroids and possibly ornithomimosaurs), and the relative rarity of ceratosaurs, is strikingly dissimilar to penecontemporaneous dinosaur faunas of Africa and South America, which represent an arid, lower-latitude biome. Similarities between dinosaur faunas of Victoria and the northern continents concern the proportional representatation of higher clades, and may result from the prevailing temperate-polar climate of Australia, especially at high latitudes in Victoria, which is similar to the predominant warm-temperate climate of Laurasia, but distinct from the arid climate zone that covered extensive areas of Gondwana. Most dinosaur groups probably attained a near-cosmopolitan distribution in the Jurassic, prior to fragmentation of the Pangaean supercontinent, and some aspects of the hallmark

  16. Theropod Fauna from Southern Australia Indicates High Polar Diversity and Climate-Driven Dinosaur Provinciality

    Science.gov (United States)

    Benson, Roger B. J.; Rich, Thomas H.; Vickers-Rich, Patricia; Hall, Mike

    2012-01-01

    The Early Cretaceous fauna of Victoria, Australia, provides unique data on the composition of high latitude southern hemisphere dinosaurs. We describe and review theropod dinosaur postcranial remains from the Aptian–Albian Otway and Strzelecki groups, based on at least 37 isolated bones, and more than 90 teeth from the Flat Rocks locality. Several specimens of medium- and large-bodied individuals (estimated up to ∼8.5 metres long) represent allosauroids. Tyrannosauroids are represented by elements indicating medium body sizes (∼3 metres long), likely including the holotype femur of Timimus hermani, and a single cervical vertebra represents a juvenile spinosaurid. Single specimens representing medium- and small-bodied theropods may be referrable to Ceratosauria, Ornithomimosauria, a basal coelurosaur, and at least three taxa within Maniraptora. Thus, nine theropod taxa may have been present. Alternatively, four distinct dorsal vertebrae indicate a minimum of four taxa. However, because most taxa are known from single bones, it is likely that small-bodied theropod diversity remains underestimated. The high abundance of allosauroids and basal coelurosaurs (including tyrannosauroids and possibly ornithomimosaurs), and the relative rarity of ceratosaurs, is strikingly dissimilar to penecontemporaneous dinosaur faunas of Africa and South America, which represent an arid, lower-latitude biome. Similarities between dinosaur faunas of Victoria and the northern continents concern the proportional representatation of higher clades, and may result from the prevailing temperate–polar climate of Australia, especially at high latitudes in Victoria, which is similar to the predominant warm–temperate climate of Laurasia, but distinct from the arid climate zone that covered extensive areas of Gondwana. Most dinosaur groups probably attained a near-cosmopolitan distribution in the Jurassic, prior to fragmentation of the Pangaean supercontinent, and some aspects of the

  17. Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time

    Science.gov (United States)

    Larson, Derek W.; Currie, Philip J.

    2013-01-01

    Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian). It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed) from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth will help illuminate

  18. RIVERSIDE WALK

    Directory of Open Access Journals (Sweden)

    Pablo Fernández Marmisole

    2015-06-01

    Full Text Available Since 2009, and as part of the Neighborhood Law (Ley de Barrios of Catalonia there is a strategic plan to integrate neighborhoods Baró de Viver and Bon Pastor in the city of Barcelona. The guidelines of the plan are to improve public space and to better connect neighborhoods to each other and the adjoining districts and municipalities. Within the strategy includes opening the Besos River to the urban territory through green corridors and installation of equipment. In this sense, the argument is to provide qualified public space to encourage the urban cohesiveness of the neighborhoods through the creation of a new Riverside Walk. The project consists in converting an urban highway into a pacified walk. The stroll also attempts to pacify the area by removing the visual and acoustic pollution caused by the Ronda Litoral (Highway next to the Besos River. In response to this problem the project consists in covering the Ronda Litoral, creating 1.5km of qualified public space, where a set of vegetation and the generation of sun areas will create different spaces that invigorate the territory and connect the neighborhoods. The platform covering the Ronda Litoral includes peaceful meetings with each and every one of the streets that are right with it. The Riverside Walk will be found within less than 400m from 4 metro stations and will have three pedestrian walkways as an access to Barcelona from the neighboring municipality of Santa Coloma. The installation of common equipment, to be shared by the two neighborhoods in the central part of the Riverside Walk is a guiding principle of the integrated strategy. Within the guidelines of the plan for the area of Ley de Barrios lies the importance of public participation; in that sense it is contemplated a participatory process from the initial design phase of the stroll, where subject for debate, reflection and proposal neighbors will design the walk and their equipment. The process will contemplate since the

  19. Edentulism, beaks, and biomechanical innovations in the evolution of theropod dinosaurs.

    Science.gov (United States)

    Lautenschlager, Stephan; Witmer, Lawrence M; Altangerel, Perle; Rayfield, Emily J

    2013-12-17

    Maniraptoriformes, the speciose group of derived theropod dinosaurs that ultimately gave rise to modern birds, display a diverse and remarkable suite of skeletal adaptations. Apart from the evolution of flight, a large-scale change in dietary behavior appears to have been one of the main triggers for specializations in the bauplan of these derived theropods. Among the different skeletal specializations, partial or even complete edentulism and the development of keratinous beaks form a recurring and persistent trend in from the evolution of derived nonavian dinosaurs. Therizinosauria is an enigmatic maniraptoriform clade, whose members display these and other osteological characters thought to be correlated with the shift from carnivory to herbivory. This makes therizinosaurians prime candidates to assess the functional significance of these morphological characters. Based on a highly detailed biomechanical model of Erlikosaurus andrewsi, a therizinosaurid from the Upper Cretaceous of Mongolia, different morphological configurations incorporating soft-tissue structures, such as a keratinous rhamphotheca, are evaluated for their biomechanical performance. Our results indicate that the development of beaks and the presence of a keratinous rhamphotheca would have helped to dissipate stress and strain, making the rostral part of the skull less susceptible to bending and displacement, and this benefit may extend to other vertebrate clades that possess rhamphothecae. Keratinous beaks, paralleled by edentulism, thus represent an evolutionary innovation developed early in derived theropods to enhance cranial stability, distinct to postulated mass-saving benefits associated with the origin of flight.

  20. The behavioral implications of a multi-individual bonebed of a small theropod dinosaur.

    Directory of Open Access Journals (Sweden)

    Lucio M Ibiricu

    Full Text Available BACKGROUND: Central Patagonia, Argentina, preserves an abundant and rich fossil record. Among vertebrate fossils from the Upper Cretaceous Bajo Barreal Formation of Patagonia, five individuals of the small, non-avian theropod dinosaur Aniksosaurus darwini were recovered. Group behavior is an important aspect of dinosaur paleoecology, but it is not well-documented and is poorly understood among non-avian Theropoda. METHODS/PRINCIPAL FINDINGS: The taphonomic association of individuals from the Bajo Barreal Formation and aspects of their bone histology suggest gregarious behavior for Aniksosaurus, during at least a portion of the life history of this species. Histology indicates that the specimens were juvenile to sub-adult individuals. In addition, morphological differences between individuals, particularly proportions of the appendicular bones, are probably related to body-size dimorphism rather than ontogenetic stage. CONCLUSIONS/SIGNIFICANCE: Gregarious behaviour may have conferred a selective advantage on Aniksosaurus individuals, contributing to their successful exploitation of the Cretaceous paleoenvironment preserved in the Bajo Barreal Formation. The monospecific assemblage of Aniksosaurus specimens constitutes only the second body fossil association of small, coelurosaurian theropods in South America and adds valuable information about the paleoecologies of non-avian theropod dinosaurs, particularly in the early Late Cretaceous of Patagonia.

  1. A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings.

    Science.gov (United States)

    Xu, Xing; Zheng, Xiaoting; Sullivan, Corwin; Wang, Xiaoli; Xing, Lida; Wang, Yan; Zhang, Xiaomei; O'Connor, Jingmai K; Zhang, Fucheng; Pan, Yanhong

    2015-05-07

    The wings of birds and their closest theropod relatives share a uniform fundamental architecture, with pinnate flight feathers as the key component. Here we report a new scansoriopterygid theropod, Yi qi gen. et sp. nov., based on a new specimen from the Middle-Upper Jurassic period Tiaojishan Formation of Hebei Province, China. Yi is nested phylogenetically among winged theropods but has large stiff filamentous feathers of an unusual type on both the forelimb and hindlimb. However, the filamentous feathers of Yi resemble pinnate feathers in bearing morphologically diverse melanosomes. Most surprisingly, Yi has a long rod-like bone extending from each wrist, and patches of membranous tissue preserved between the rod-like bones and the manual digits. Analogous features are unknown in any dinosaur but occur in various flying and gliding tetrapods, suggesting the intriguing possibility that Yi had membranous aerodynamic surfaces totally different from the archetypal feathered wings of birds and their closest relatives. Documentation of the unique forelimbs of Yi greatly increases the morphological disparity known to exist among dinosaurs, and highlights the extraordinary breadth and richness of the evolutionary experimentation that took place close to the origin of birds.

  2. Didactyl tracks of paravian theropods (Maniraptora from the ?Middle Jurassic of Africa.

    Directory of Open Access Journals (Sweden)

    Alexander Mudroch

    Full Text Available BACKGROUND: A new dinosaur tracksite from ?Middle Jurassic sediments of the Irhazer Group on the plains of Agadez (Rep. Niger, northwest Africa revealed extraordinarily well preserved didactyl tracks of a digitigrade bipedal trackmaker. The distinct morphology of the pes imprints indicates a theropod trackmaker from a paravian maniraptoran closely related to birds. METHODOLOGY/PRINCIPAL FINDINGS: The early age and the morphological traits of the tracks allow for description of the new ichnotaxon Paravipus didactyloides. A total of 120 tracks are assigned to 5 individual trackways. The 'medium-sized' tracks with an average footprint length of 27.5 cm and footprint width of 23.1 cm are deeply imprinted into the track bearing sandstone. CONCLUSIONS/SIGNIFICANCE: A comparison with other didactyl tracks gives new insights into the foot morphology of advanced maniraptoran theropods and contributes to knowledge of their evolutionary history. The new ichnotaxon takes an important position in the ichnological fossil record of Gondwana and the mid-Jurassic biota worldwide, because it is among the earliest known records of paravian maniraptorans and of didactyl theropod tracks from Africa.

  3. Evolution of olfaction in non-avian theropod dinosaurs and birds.

    Science.gov (United States)

    Zelenitsky, Darla K; Therrien, François; Ridgely, Ryan C; McGee, Amanda R; Witmer, Lawrence M

    2011-12-22

    Little is known about the olfactory capabilities of extinct basal (non-neornithine) birds or the evolutionary changes in olfaction that occurred from non-avian theropods through modern birds. Although modern birds are known to have diverse olfactory capabilities, olfaction is generally considered to have declined during avian evolution as visual and vestibular sensory enhancements occurred in association with flight. To test the hypothesis that olfaction diminished through avian evolution, we assessed relative olfactory bulb size, here used as a neuroanatomical proxy for olfactory capabilities, in 157 species of non-avian theropods, fossil birds and living birds. We show that relative olfactory bulb size increased during non-avian maniraptoriform evolution, remained stable across the non-avian theropod/bird transition, and increased during basal bird and early neornithine evolution. From early neornithines through a major part of neornithine evolution, the relative size of the olfactory bulbs remained stable before decreasing in derived neoavian clades. Our results show that, rather than decreasing, the importance of olfaction actually increased during early bird evolution, representing a previously unrecognized sensory enhancement. The relatively larger olfactory bulbs of earliest neornithines, compared with those of basal birds, may have endowed neornithines with improved olfaction for more effective foraging or navigation skills, which in turn may have been a factor allowing them to survive the end-Cretaceous mass extinction.

  4. A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids

    Science.gov (United States)

    Novas, Fernando E.; Valais, Silvina; Vickers-Rich, Pat; Rich, Tom

    2005-05-01

    The Cretaceous Carcharodontosauridae is the latest clade of carnosaurs, including the largest predatory dinosaurs yet recorded. Albeit spectacular for their size, the skeletal anatomy of these theropods remains poorly-known, and their diversity was until recently restricted to two Cenomanian species: the highly derived Giganotosaurus carolinii, from southern South America, and the incompletely known Carcharodontosaurus saharicus, from northern Africa. Here we describe an older and basal member of the group, Tyrannotitan chubutensis gen. et sp. nov., from Aptian strata of Patagonia, Argentina. The new taxon gives new insights into the systematics and evolution of carcharodontosaurids and offers a better understanding of the evolution of Southern theropod faunas. We suggest that carcharodontosaurids radiated in Gondwana sharing with spinosaurids the role of top-predators until their extinction in Cenomanian Turonian times. During this interval, the diplodocoid sauropods and giant titanosaurians went extinct (probably as part of a global-scale crisis), and the smaller abelisaurid theropods took dominance, reigning until the end of the Cretaceous. Electronic Supplementary Material is available.

  5. Toe Walking in Children

    Science.gov (United States)

    ... normally, toe walking is unlikely to be a cause for concern. Toe walking sometimes can result from certain conditions, including cerebral palsy, muscular dystrophy and autism spectrum disorder. Symptoms Toe walking is walking on the toes ...

  6. High on Walking: Conquering Everyday Life.

    Science.gov (United States)

    Martinsen, Bente; Haahr, Anita; Dreyer, Pia; Norlyk, Annelise

    2018-05-01

    The aim of this study is to discuss the meaning of walking impairment among people who have previously been able to walk on their own. The study is based on findings from three different life situations: older people recovering after admission in intermediate care, people who have lost a leg, and people who live with Parkinson's disease. The analysis of the data is inspired by Paul Ricoeur's philosophy of interpretation. Four themes were identified: (a) I feel high in two ways; (b) Walking has to be automatic; (c) Every Monday, I walk with the girls in the park; and (d) I dream of walking along the street without sticks and things like that. The findings demonstrate that inability to walk profoundly affected the participants' lives. Other problems seemed small by comparison because walking impairment was at the same time experienced as a concrete physical limit and an existential deficit.

  7. The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora: dromaeosaurid or flightless bird?

    Directory of Open Access Journals (Sweden)

    Andrea Cau

    2015-06-01

    Full Text Available The exceptionally well-preserved Romanian dinosaur Balaur bondoc is the most complete theropod known to date from the Upper Cretaceous of Europe. Previous studies of this remarkable taxon have included its phylogenetic interpretation as an aberrant dromaeosaurid with velociraptorine affinities. However, Balaur displays a combination of both apparently plesiomorphic and derived bird-like characters. Here, we analyse those features in a phylogenetic revision and show how they challenge its referral to Dromaeosauridae. Our reanalysis of two distinct phylogenetic datasets focusing on basal paravian taxa supports the reinterpretation of Balaur as an avialan more crownward than Archaeopteryx but outside of Pygostylia, and as a flightless taxon within a paraphyletic assemblage of long-tailed birds. Our placement of Balaur within Avialae is not biased by character weighting. The placement among dromaeosaurids resulted in a suboptimal alternative that cannot be rejected based on the data to hand. Interpreted as a dromaeosaurid, Balaur has been assumed to be hypercarnivorous and predatory, exhibiting a peculiar morphology influenced by island endemism. However, a dromaeosaurid-like ecology is contradicted by several details of Balaur’s morphology, including the loss of a third functional manual digit, the non-ginglymoid distal end of metatarsal II, and a non-falciform ungual on the second pedal digit that lacks a prominent flexor tubercle. Conversely, an omnivorous ecology is better supported by Balaur’s morphology and is consistent with its phylogenetic placement within Avialae. Our reinterpretation of Balaur implies that a superficially dromaeosaurid-like taxon represents the enlarged, terrestrialised descendant of smaller and probably volant ancestors.

  8. Air-filled postcranial bones in theropod dinosaurs: physiological implications and the 'reptile'-bird transition.

    Science.gov (United States)

    Benson, Roger B J; Butler, Richard J; Carrano, Matthew T; O'Connor, Patrick M

    2012-02-01

    Pneumatic (air-filled) postcranial bones are unique to birds among extant tetrapods. Unambiguous skeletal correlates of postcranial pneumaticity first appeared in the Late Triassic (approximately 210 million years ago), when they evolved independently in several groups of bird-line archosaurs (ornithodirans). These include the theropod dinosaurs (of which birds are extant representatives), the pterosaurs, and sauropodomorph dinosaurs. Postulated functions of skeletal pneumatisation include weight reduction in large-bodied or flying taxa, and density reduction resulting in energetic savings during foraging and locomotion. However, the influence of these hypotheses on the early evolution of pneumaticity has not been studied in detail previously. We review recent work on the significance of pneumaticity for understanding the biology of extinct ornithodirans, and present detailed new data on the proportion of the skeleton that was pneumatised in 131 non-avian theropods and Archaeopteryx. This includes all taxa known from significant postcranial remains. Pneumaticity of the cervical and anterior dorsal vertebrae occurred early in theropod evolution. This 'common pattern' was conserved on the line leading to birds, and is likely present in Archaeopteryx. Increases in skeletal pneumaticity occurred independently in as many as 12 lineages, highlighting a remarkably high number of parallel acquisitions of a bird-like feature among non-avian theropods. Using a quantitative comparative framework, we show that evolutionary increases in skeletal pneumaticity are significantly concentrated in lineages with large body size, suggesting that mass reduction in response to gravitational constraints at large body sizes influenced the early evolution of pneumaticity. However, the body size threshold for extensive pneumatisation is lower in theropod lineages more closely related to birds (maniraptorans). Thus, relaxation of the relationship between body size and pneumatisation preceded

  9. Time dependency of walking classification in stroke.

    NARCIS (Netherlands)

    Kollen, B.; Kwakkel, G.; Lindeman, E.

    2006-01-01

    BACKGROUND AND PURPOSE: To facilitate optimal stroke rehabilitation, valid interpretation of observed functional recovery is required. The purpose of this study was to examine the longitudinal relationship between comfortable walking speed and Functional Ambulation Categories (FAC) scores for

  10. Theropod courtship: large scale physical evidence of display arenas and avian-like scrape ceremony behaviour by Cretaceous dinosaurs

    Science.gov (United States)

    Lockley, Martin G.; McCrea, Richard T.; Buckley, Lisa G.; Deock Lim, Jong; Matthews, Neffra A.; Breithaupt, Brent H.; Houck, Karen J.; Gierliński, Gerard D.; Surmik, Dawid; Soo Kim, Kyung; Xing, Lida; Yong Kong, Dal; Cart, Ken; Martin, Jason; Hadden, Glade

    2016-01-01

    Relationships between non-avian theropod dinosaurs and extant and fossil birds are a major focus of current paleobiological research. Despite extensive phylogenetic and morphological support, behavioural evidence is mostly ambiguous and does not usually fossilize. Thus, inferences that dinosaurs, especially theropods displayed behaviour analogous to modern birds are intriguing but speculative. Here we present extensive and geographically widespread physical evidence of substrate scraping behavior by large theropods considered as compelling evidence of “display arenas” or leks, and consistent with “nest scrape display” behaviour among many extant ground-nesting birds. Large scrapes, up to 2 m in diameter, occur abundantly at several Cretaceous sites in Colorado. They constitute a previously unknown category of large dinosaurian trace fossil, inferred to fill gaps in our understanding of early phases in the breeding cycle of theropods. The trace makers were probably lekking species that were seasonally active at large display arena sites. Such scrapes indicate stereotypical avian behaviour hitherto unknown among Cretaceous theropods, and most likely associated with terrirorial activity in the breeding season. The scrapes most probably occur near nesting colonies, as yet unknown or no longer preserved in the immediate study areas. Thus, they provide clues to paleoenvironments where such nesting sites occurred.

  11. Theropod courtship: large scale physical evidence of display arenas and avian-like scrape ceremony behaviour by Cretaceous dinosaurs.

    Science.gov (United States)

    Lockley, Martin G; McCrea, Richard T; Buckley, Lisa G; Lim, Jong Deock; Matthews, Neffra A; Breithaupt, Brent H; Houck, Karen J; Gierliński, Gerard D; Surmik, Dawid; Kim, Kyung Soo; Xing, Lida; Kong, Dal Yong; Cart, Ken; Martin, Jason; Hadden, Glade

    2016-01-07

    Relationships between non-avian theropod dinosaurs and extant and fossil birds are a major focus of current paleobiological research. Despite extensive phylogenetic and morphological support, behavioural evidence is mostly ambiguous and does not usually fossilize. Thus, inferences that dinosaurs, especially theropods displayed behaviour analogous to modern birds are intriguing but speculative. Here we present extensive and geographically widespread physical evidence of substrate scraping behavior by large theropods considered as compelling evidence of "display arenas" or leks, and consistent with "nest scrape display" behaviour among many extant ground-nesting birds. Large scrapes, up to 2 m in diameter, occur abundantly at several Cretaceous sites in Colorado. They constitute a previously unknown category of large dinosaurian trace fossil, inferred to fill gaps in our understanding of early phases in the breeding cycle of theropods. The trace makers were probably lekking species that were seasonally active at large display arena sites. Such scrapes indicate stereotypical avian behaviour hitherto unknown among Cretaceous theropods, and most likely associated with terrirorial activity in the breeding season. The scrapes most probably occur near nesting colonies, as yet unknown or no longer preserved in the immediate study areas. Thus, they provide clues to paleoenvironments where such nesting sites occurred.

  12. An enigmatic, diminutive theropod footprint in the shallow marine Pliensbachian Hasle Formation, Bornholm, Denmark

    DEFF Research Database (Denmark)

    Milàn, Jesper; Surlyk, Finn

    2015-01-01

    localities around the world. The occurrence of a diminutive dinosaur footprint in a shallow marine sandstone is enigmatic. The well-defined morphology of the footprint, together with the very small size of the trackmaker, excludes the possibility that the track was emplaced by a swimming or wading animal......A well-preserved three-toed footprint, measuring 34 mm in length from a very small predatory dinosaur with an estimated hip height of 153 mm and a total body length around 50 cm including tail, is reported from the type section of the marine Lower Jurassic (Pliensbachian), Hasle Formation...... found footprint is interpreted to have walked in shallow beach pools, thus explaining the strange occurrence of the footprint in a marine deposit....

  13. A theropod dinosaur embryo and the affinities of the flaming cliffs dinosaur eggs.

    Science.gov (United States)

    Norell, M A; Clark, J M; Demberelyin, D; Rhinchen, B; Chiappe, L M; Davidson, A R; McKenna, M C; Altangerel, P; Novacek, M J

    1994-11-04

    An embryonic skeleton of a nonavian theropod dinosaur was found preserved in an egg from Upper Cretaceous rocks in the Gobi Desert of Mongolia. Cranial features identify the embryo as a member of Oviraptoridae. Two embryo-sized skulls of dromaeosaurids, similar to that of Velociraptor, were also recovered in the nest. The eggshell microstructure is similar to that of ratite birds and is of a type common in the Djadokhta Formation at the Flaming Cliffs (Bayn Dzak). Discovery of a nest of such eggs at the Flaming Cliffs in 1923, beneath the Oviraptor philoceratops holotype, suggests that this dinosaur may have been a brooding adult.

  14. New theropod, thyreophoran, and small sauropod tracks from the Middle Jurassic Bagå Formation, Bornholm, Denmark

    DEFF Research Database (Denmark)

    Milàn, Jesper

    2011-01-01

    Three new dinosaur tracks are described from the Middle Jurassic Bagå Formation of Bornholm, Denmark. The tracks are all preserved as natural casts on the underside of fluvial sandstone blocks originating from the old Hasle Klinkefabrik’s clay pit, now called Pyritsøen. The new tracks are from...... a medium-sized theropod, a thyreophoran, and a small sauropod. Together with a hyreophoran track and large sauropod tracks described in 2005, the Middle Jurassic dinosaur fauna of Bornholm now comprises theropods, two sizes of sauropods and at least one type of thyreophoran dinosaur. This is important...

  15. Allegheny County Walk Scores

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Walk Score measures the walkability of any address using a patented system developed by the Walk Score company. For each 2010 Census Tract centroid, Walk Score...

  16. Phylogenetic eigenvectors and nonstationarity in the evolution of theropod dinosaur skulls.

    Science.gov (United States)

    Diniz-Filho, J A F; Alves, D M C C; Villalobos, F; Sakamoto, M; Brusatte, S L; Bini, L M

    2015-07-01

    Despite the long-standing interest in nonstationarity of both phenotypic evolution and diversification rates, only recently have methods been developed to study this property. Here, we propose a methodological expansion of the phylogenetic signal-representation (PSR) curve based on phylogenetic eigenvectors to test for nonstationarity. The PSR curve is built by plotting the coefficients of determination R(2) from phylogenetic eigenvector regression (PVR) models increasing the number of phylogenetic eigenvectors against the accumulated eigenvalues. The PSR curve is linear under a stationary model of trait evolution (i.e. the Brownian motion model). Here we describe the distribution of shifts in the models R(2) and used a randomization procedure to compare observed and simulated shifts along the PSR curve, which allowed detecting nonstationarity in trait evolution. As an applied example, we show that the main evolutionary pattern of variation in the theropod dinosaur skull was nonstationary, with a significant shift in evolutionary rates in derived oviraptorosaurs, an aberrant group of mostly toothless, crested, birdlike theropods. This result is also supported by a recently proposed Bayesian-based method (AUTEUR). A significant deviation between Ceratosaurus and Limusaurus terminal branches was also detected. We purport that our new approach is a valuable tool for evolutionary biologists, owing to its simplicity, flexibility and comprehensiveness. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  17. Apparent sixth sense in theropod evolution: The making of a Cretaceous weathervane.

    Directory of Open Access Journals (Sweden)

    Bruce M Rothschild

    Full Text Available Two separate and distinctive skills are necessary to find prey: Detection of its presence and determination of its location. Surface microscopy of the dentary of albertosaurines revealed a previously undescribed sensory modification, as will be described here. While dentary "foramina" were previously thought to contain tactile sensory organs, the potential function of this theropod modification as a unique localizing system is explored in this study.Dentary surface perforations were examined by surface epi-illumination microscopy in tyrannosaurine and albertosaurine dinosaurs to characterize their anatomy. Fish lateral lines were examined as potentially comparable structures.In contrast to the subsurface vascular bifurcation noted in tyrannosaurines (which lack a lateral dentary surface groove, the area subjacent to the apertures in albertosaurine grooves has the appearance of an expanded chamber. That appearance seemed to be indistinguishable from the lateral line of fish.Dentary groove apertures in certain tyrannosaurid lines (specifically albertosaurines not only have a unique appearance, but one with significant functional and behavior implications. The appearance of the perforations in the dentary groove of albertosaurines mirrors that previously noted only with specialized neurologic structures accommodating derived sensory functions, as seen in the lateral line of fish. The possibility that this specialized morphology could also represent a unique function in albertosaurine theropods for interacting with the environment or facilitating prey acquisition cannot be ignored. It is suggested that these expanded chambers function in perceiving and aligning the body relative to the direction of wind, perhaps a Cretaceous analogue of the contemporary midwestern weathervane.

  18. Dental morphology and variation in theropod dinosaurs: implications for the taxonomic identification of isolated teeth.

    Science.gov (United States)

    Smith, Joshua B; Vann, David R; Dodson, Peter

    2005-08-01

    Isolated theropod teeth are common Mesozoic fossils and would be an important data source for paleoecology biogeography if they could be reliably identified as having come from particular taxa. However, obtaining identifications is confounded by a paucity of easily identifiable characters. Here we discuss a quantitative methodology designed to provide defensible identifications of isolated teeth using Tyrannosaurus as a comparison taxon. We created a standard data set based as much as possible on teeth of known taxonomic affinity against which to compare isolated crowns. Tooth morphology was described using measured variables describing crown length, base length and width, and derived variables related to basal shape, squatness, mesial curve shape, apex location with respect to base, and denticle size. Crown curves were described by fitting the power function Y = a + bX(0.5) to coordinate data collected from lateral-view images of mesial curve profiles. The b value from these analyses provides a measure of curvature. Discriminant analyses compared isolated teeth of various taxonomic affinities against the standard. The analyses classified known Tyrannosaurus teeth with Tyrannosaurus and separated most teeth known not to be Tyrannosaurus from Tyrannosaurus. They had trouble correctly classifying teeth that were very similar to Tyrannosaurus and for which there were few data in the standard. However, the results indicate that expanding the standard should facilitate the identification of numerous types of isolated theropod teeth. (c) 2005 Wiley-Liss, Inc.

  19. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers

    Science.gov (United States)

    Lefèvre, Ulysse; Cau, Andrea; Cincotta, Aude; Hu, Dongyu; Chinsamy, Anusuya; Escuillié, François; Godefroit, Pascal

    2017-10-01

    Genuine fossils with exquisitely preserved plumage from the Late Jurassic and Early Cretaceous of northeastern China have recently revealed that bird-like theropod dinosaurs had long pennaceous feathers along their hindlimbs and may have used their four wings to glide or fly. Thus, it has been postulated that early bird flight might initially have involved four wings (Xu et al. Nature 421:335-340, 2003; Hu et al. Nature 461:640-643, 2009; Han et al. Nat Commun 5:4382, 2014). Here, we describe Serikornis sungei gen. et sp. nov., a new feathered theropod from the Tiaojishan Fm (Late Jurassic) of Liaoning Province, China. Its skeletal morphology suggests a ground-dwelling ecology with no flying adaptations. Our phylogenetic analysis places Serikornis, together with other Late Jurassic paravians from China, as a basal paravians, outside the Eumaniraptora clade. The tail of Serikornis is covered proximally by filaments and distally by slender rectrices. Thin symmetrical remiges lacking barbules are attached along its forelimbs and elongate hindlimb feathers extend up to its toes, suggesting that hindlimb remiges evolved in ground-dwelling maniraptorans before being co-opted to an arboreal lifestyle or flight.

  20. Apparent sixth sense in theropod evolution: The making of a Cretaceous weathervane.

    Science.gov (United States)

    Rothschild, Bruce M; Naples, Virginia

    2017-01-01

    Two separate and distinctive skills are necessary to find prey: Detection of its presence and determination of its location. Surface microscopy of the dentary of albertosaurines revealed a previously undescribed sensory modification, as will be described here. While dentary "foramina" were previously thought to contain tactile sensory organs, the potential function of this theropod modification as a unique localizing system is explored in this study. Dentary surface perforations were examined by surface epi-illumination microscopy in tyrannosaurine and albertosaurine dinosaurs to characterize their anatomy. Fish lateral lines were examined as potentially comparable structures. In contrast to the subsurface vascular bifurcation noted in tyrannosaurines (which lack a lateral dentary surface groove), the area subjacent to the apertures in albertosaurine grooves has the appearance of an expanded chamber. That appearance seemed to be indistinguishable from the lateral line of fish. Dentary groove apertures in certain tyrannosaurid lines (specifically albertosaurines) not only have a unique appearance, but one with significant functional and behavior implications. The appearance of the perforations in the dentary groove of albertosaurines mirrors that previously noted only with specialized neurologic structures accommodating derived sensory functions, as seen in the lateral line of fish. The possibility that this specialized morphology could also represent a unique function in albertosaurine theropods for interacting with the environment or facilitating prey acquisition cannot be ignored. It is suggested that these expanded chambers function in perceiving and aligning the body relative to the direction of wind, perhaps a Cretaceous analogue of the contemporary midwestern weathervane.

  1. Speed related changes in muscle activity from normal to very slow walking speeds

    NARCIS (Netherlands)

    den Otter, A.R.; Mulder, T.; Duysens, J.

    2004-01-01

    The study of neuromuscular activity at very slow walking speeds may lead to a better understanding of the mechanisms underlying speed regulation during walking, and may aid the interpretation of gait data in patients who walk slowly. Extreme reductions in walking speed will cause changes in

  2. Celestial Walk: A Terminating Oblivious Walk for Convex Subdivisions

    OpenAIRE

    Kuijper, Wouter; Ermolaev, Victor; Devillers, Olivier

    2017-01-01

    We present a new oblivious walking strategy for convex subdivisions. Our walk is faster than the straight walk and more generally applicable than the visibility walk. To prove termination of our walk we use a novel monotonically decreasing distance measure.

  3. Complete forelimb myology of the basal theropod dinosaur Tawa hallae based on a novel robust muscle reconstruction method.

    Science.gov (United States)

    Burch, Sara H

    2014-09-01

    The forelimbs of nonavian theropod dinosaurs have been the subject of considerable study and speculation due to their varied morphology and role in the evolution of flight. Although many studies on the functional morphology of a limb require an understanding of its musculature, comparatively little is known about the forelimb myology of theropods and other bipedal dinosaurs. Previous phylogenetically based myological reconstructions have been limited to the shoulder, restricting their utility in analyses of whole-limb function. The antebrachial and manual musculature in particular have remained largely unstudied due to uncertain muscular homologies in archosaurs. Through analysis of the musculature of extant taxa in a robust statistical framework, this study presents new hypotheses of homology for the distal limb musculature of archosaurs and provides the first complete reconstruction of dinosaurian forelimb musculature, including the antebrachial and intrinsic manual muscles. Data on the forelimb myology of a broad sample of extant birds, crocodylians, lizards, and turtles were analyzed using maximum likelihood ancestral state reconstruction and examined together with the osteology of the early theropod Tawa hallae from the Late Triassic of New Mexico to formulate a complete plesiomorphic myology for the theropod forelimb. Comparisons with previous reconstructions show that the shoulder musculature of basal theropods is more similar to that of basal ornithischians and sauropodomorphs than to that of dromaeosaurids. Greater development of the supracoracoideus and deltoideus musculature in theropods over other bipedal dinosaurs correlates with stronger movements of the forelimb at the shoulder and an emphasis on apprehension of relatively large prey. This emphasis is further supported by the morphology of the antebrachium and the intrinsic manual musculature, which exhibit a high degree of excursion and a robust morphology well-suited for powerful digital flexion

  4. Influence of rotational inertia on turning performance of theropod dinosaurs: clues from humans with increased rotational inertia.

    Science.gov (United States)

    Carrier, D R; Walter, R M; Lee, D V

    2001-11-01

    The turning agility of theropod dinosaurs may have been severely limited by the large rotational inertia of their horizontal trunks and tails. Bodies with mass distributed far from the axis of rotation have much greater rotational inertia than bodies with the same mass distributed close to the axis of rotation. In this study, we increased the rotational inertia about the vertical axis of human subjects 9.2-fold, to match our estimate for theropods the size of humans, and measured the ability of the subjects to turn. To determine the effect of the increased rotational inertia on maximum turning capability, five subjects jumped vertically while attempting to rotate as far as possible about their vertical axis. This test resulted in a decrease in the average angle turned to 20 % of the control value. We also tested the ability of nine subjects to run as rapidly as possible through a tight slalom course of six 90 degrees turns. When the subjects ran with the 9.2-fold greater rotational inertia, the average velocity through the course decreased to 77% of the control velocity. When the subjects ran the same course but were constrained as to where they placed their feet, the average velocity through the course decreased to 65 % of the control velocity. These results are consistent with the hypothesis that rotational inertia may have limited the turning performance of theropods. They also indicate that the effect of rotational inertia on turning performance is dependent on the type of turning behavior. Characters such as retroverted pubes, reduced tail length, decreased body size, pneumatic vertebrae and the absence of teeth reduced rotational inertia in derived theropods and probably, therefore, improved their turning agility. To reduce rotational inertia, theropods may have run with an arched back and tail, an S-curved neck and forelimbs held backwards against the body.

  5. Fire-Walking

    Science.gov (United States)

    Willey, David

    2010-01-01

    This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

  6. Spectroscopic Analysis of a Theropod Dinosaur (Reptilia, Archosauria from the Ipubi Formation, Araripe Basin, Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    João Hermínio da Silva

    2013-01-01

    Full Text Available The Araripe Sedimentary Basin is known by the excellence of its fossils, regarding the preservation, diversity, and quantity. Here, we present a spectroscopic analysis using several experimental techniques (X-ray energy dispersion spectroscopy, Fourier-transform infrared spectroscopy as well as X-ray diffraction and thermogravimetric analysis applied in small fragments of bones from the posterior members of a theropod dinosaur. The results agree regarding the different composition of the stone matrix and the fossilized bone, indicating a partial substitution of the material by elements present in the depositional environment. However, differently from what is believed to occur, there is evidence that pyritization is not the only mechanism of fossilization for a specimen of Ipubi formation, but calcification, additionally, plays an important role in the fossil production of this Formation.

  7. Gait or Walking Problems

    Science.gov (United States)

    Gait or Walking Problems the basic facts multiple sclerosis Many people with MS will experience difficulty with walking, which is also called ambulation. The term “gait” refers more specifically to the manner or pattern ...

  8. What Is Walking Pneumonia?

    Science.gov (United States)

    ... pneumonia: What does it mean? What is walking pneumonia? How is it different from regular pneumonia? Answers from Eric J. Olson, M.D. Walking pneumonia is an informal term for pneumonia that isn' ...

  9. Craniocervical myology and functional morphology of the small-headed therizinosaurian theropods Falcarius utahensis and Nothronychus mckinleyi.

    Directory of Open Access Journals (Sweden)

    David K Smith

    Full Text Available Therizinosaurs represent a highly unusual clade of herbivorous theropods from the Cretaceous of North America and Asia. Following descriptions of the basicrania of the North American therizinosaurs Falcarius utahenisis and Nothronychus mckinleyi, the craniocervical musculature in both taxa is reconstructed using Tyrannosaurus, Allosaurus, and some extant birds as models. These muscles are subdivided into functional groups as dorsiflexors, lateroflexors, and ventroflexors. Lateroflexors and dorsiflexors in Nothronychus, but not Falcarius, are reduced, from the plesiomorphic theropod condition, but are still well developed. Attachments in both genera are favorable for an increase in ventroflexion in feeding, convergent with Allosaurus fragilis. Falcarius and Nothronychus are both characterized by a flat occipital condyle, followed by centra with shallow articular facets suggesting neck function very similar to that of an ostrich Struthio camelus. Neck movement was a combined result of minimal movement between the individual cervical vertebrae.

  10. Craniocervical myology and functional morphology of the small-headed therizinosaurian theropods Falcarius utahensis and Nothronychus mckinleyi.

    Science.gov (United States)

    Smith, David K

    2015-01-01

    Therizinosaurs represent a highly unusual clade of herbivorous theropods from the Cretaceous of North America and Asia. Following descriptions of the basicrania of the North American therizinosaurs Falcarius utahenisis and Nothronychus mckinleyi, the craniocervical musculature in both taxa is reconstructed using Tyrannosaurus, Allosaurus, and some extant birds as models. These muscles are subdivided into functional groups as dorsiflexors, lateroflexors, and ventroflexors. Lateroflexors and dorsiflexors in Nothronychus, but not Falcarius, are reduced, from the plesiomorphic theropod condition, but are still well developed. Attachments in both genera are favorable for an increase in ventroflexion in feeding, convergent with Allosaurus fragilis. Falcarius and Nothronychus are both characterized by a flat occipital condyle, followed by centra with shallow articular facets suggesting neck function very similar to that of an ostrich Struthio camelus. Neck movement was a combined result of minimal movement between the individual cervical vertebrae.

  11. Quantum walk computation

    International Nuclear Information System (INIS)

    Kendon, Viv

    2014-01-01

    Quantum versions of random walks have diverse applications that are motivating experimental implementations as well as theoretical studies. Recent results showing quantum walks are “universal for quantum computation” relate to algorithms, to be run on quantum computers. We consider whether an experimental implementation of a quantum walk could provide useful computation before we have a universal quantum computer

  12. Small theropod teeth from the Late Cretaceous of the San Juan Basin, northwestern New Mexico and their implications for understanding latest Cretaceous dinosaur evolution.

    Science.gov (United States)

    Williamson, Thomas E; Brusatte, Stephen L

    2014-01-01

    Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during the Late Cretaceous, but few such specimens have been well documented from outside of the northern Rockies, making it difficult to assess Late Cretaceous dinosaur diversity and biogeographic patterns. We describe small theropod teeth from the San Juan Basin of northwestern New Mexico. These specimens were collected from strata spanning Santonian - Maastrichtian. We grouped isolated theropod teeth into several morphotypes, which we assigned to higher-level theropod clades based on possession of phylogenetic synapomorphies. We then used principal components analysis and discriminant function analyses to gauge whether the San Juan Basin teeth overlap with, or are quantitatively distinct from, similar tooth morphotypes from other geographic areas. The San Juan Basin contains a diverse record of small theropods. Late Campanian assemblages differ from approximately coeval assemblages of the northern Rockies in being less diverse with only rare representatives of troodontids and a Dromaeosaurus-like taxon. We also provide evidence that erect and recurved morphs of a Richardoestesia-like taxon represent a single heterodont species. A late Maastrichtian assemblage is dominated by a distinct troodontid. The differences between northern and southern faunas based on isolated theropod teeth provide evidence for provinciality in the late Campanian and the late Maastrichtian of North America. However, there is no indication that major components of small-bodied theropod diversity were lost

  13. Tetradactyl Footprints of an Unknown Affinity Theropod Dinosaur from the Upper Jurassic of Morocco

    Science.gov (United States)

    Nouri, Jaouad; Díaz-Martínez, Ignacio; Pérez-Lorente, Félix

    2011-01-01

    Background New tetradactyl theropod footprints from Upper Jurassic (Oxfordian-Kimmeridgian) have been found in the Iouaridène syncline (Morocco). The tracksites are at several layers in the intermediate lacustrine unit of Iouaridène Formation. The footprints were named informally in previous works “Eutynichnium atlasipodus”. We consider as nomen nudum. Methodology/Principal Findings Boutakioutichnium atlasicus ichnogen. et ichnosp. nov. is mainly characterized by the hallux impression. It is long, strong, directed medially or forward, with two digital pads and with the proximal part of the first pad in lateral position. More than 100 footprints in 15 trackways have been studied with these features. The footprints are large, 38–48 cm in length, and 26–31 cm in width. Conclusions/Significance Boutakioutichnium mainly differs from other ichnotaxa with hallux impression in lacking metatarsal marks and in not being a very deep footprint. The distinct morphology of the hallux of the Boutakioutichnium trackmaker –i.e. size and hallux position- are unique in the dinosaur autopodial record to date. PMID:22180775

  14. A new large-bodied oviraptorosaurian theropod dinosaur from the latest Cretaceous of western North America.

    Science.gov (United States)

    Lamanna, Matthew C; Sues, Hans-Dieter; Schachner, Emma R; Lyson, Tyler R

    2014-01-01

    The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs.

  15. A new large-bodied oviraptorosaurian theropod dinosaur from the latest Cretaceous of western North America.

    Directory of Open Access Journals (Sweden)

    Matthew C Lamanna

    Full Text Available The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs.

  16. The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs

    Science.gov (United States)

    Sullivan, Corwin; Hone, David W. E.; Xu, Xing; Zhang, Fucheng

    2010-01-01

    In extant birds, the hand is permanently abducted towards the ulna, and the wrist joint can bend extensively in this direction to fold the wing when not in use. Anatomically, this asymmetric mobility of the wrist results from the wedge-like shape of one carpal bone, the radiale, and from the well-developed convexity of the trochlea at the proximal end of the carpometacarpus. Among the theropod precursors of birds, a strongly convex trochlea is characteristic of Coelurosauria, a clade including the highly derived Maniraptora in addition to tyrannosaurs and compsognathids. The shape of the radiale can be quantified using a ‘radiale angle’ between the proximal and distal articular surfaces. Measurement of the radiale angle and reconstruction of ancestral states using squared-change parsimony shows that the angle was small (15°) in primitive coelurosaurs but considerably larger (25°) in primitive maniraptorans, indicating that the radiale was more wedge-shaped and the carpal joint more asymmetric. The radiale angle progressively increased still further within Maniraptora, with concurrent elongation of the forelimb feathers and the forelimb itself. Carpal asymmetry would have permitted avian-like folding of the forelimb in order to protect the plumage, an early advantage of the flexible, asymmetric wrist inherited by birds. PMID:20200032

  17. Isolated theropod teeth from the Middle Jurassic of Niger and the early dental evolution of Spinosauridae

    Directory of Open Access Journals (Sweden)

    Alejandro Serrano-Martínez

    2016-06-01

    Full Text Available Four isolated theropod teeth from the ?Bathonian “Argiles de l’Irhazer” in Niger are described. The teeth were found in association with the holotype of the basal sauropod Spinophorosaurus nigerensis. These specimens have been assigned to two different taxa by independent analyses, such as direct comparison with teeth previously described in the literature, discriminant and morphometric analyses from metric characters, and cladistic and cluster analyses from discrete characters. The results suggest that three teeth share affinities with those of Megalosauridae and Allosauridae, belonging most likely to the former. The fourth tooth might be from a member of the stem group Spinosauridae. If so, this would be the oldest representative of this clade. This tooth shows a combination of characters that are unusual in typical spinosaurid teeth (crown moderately compressed labiolingually and curved distally with minute denticles on the carina and a deeply veined enamel surface texture without apicobasal ridges. This could shed light on the morphological transition from the plesiomorphic ziphodont dental pattern to that of Spinosauridae. This tooth would also allow a better understanding of the origin of the spinosaurids, supporting a Gondwanan origin for the group.

  18. A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs.

    Science.gov (United States)

    Pol, Diego; Rauhut, Oliver W M

    2012-08-22

    Abelisaurids are a clade of large, bizarre predatory dinosaurs, most notable for their high, short skulls and extremely reduced forelimbs. They were common in Gondwana during the Cretaceous, but exceedingly rare in the Northern Hemisphere. The oldest definitive abelisaurids so far come from the late Early Cretaceous of South America and Africa, and the early evolutionary history of the clade is still poorly known. Here, we report a new abelisaurid from the Middle Jurassic of Patagonia, Eoabelisaurus mefi gen. et sp. nov., which predates the so far oldest known secure member of this lineage by more than 40 Myr. The almost complete skeleton reveals the earliest evolutionary stages of the distinctive features of abelisaurids, such as the modification of the forelimb, which started with a reduction of the distal elements. The find underlines the explosive radiation of theropod dinosaurs in the Middle Jurassic and indicates an unexpected diversity of ceratosaurs at that time. The apparent endemism of abelisauroids to southern Gondwana during Pangean times might be due to the presence of a large, central Gondwanan desert. This indicates that, apart from continent-scale geography, aspects such as regional geography and climate are important to reconstruct the biogeographical history of Mesozoic vertebrates.

  19. No evidence for directional evolution of body mass in herbivorous theropod dinosaurs.

    Science.gov (United States)

    Zanno, Lindsay E; Makovicky, Peter J

    2013-01-22

    The correlation between large body size and digestive efficiency has been hypothesized to have driven trends of increasing mass in herbivorous clades by means of directional selection. Yet, to date, few studies have investigated this relationship from a phylogenetic perspective, and none, to our knowledge, with regard to trophic shifts. Here, we reconstruct body mass in the three major subclades of non-avian theropod dinosaurs whose ecomorphology is correlated with extrinsic evidence of at least facultative herbivory in the fossil record--all of which also achieve relative gigantism (more than 3000 kg). Ordinary least-squares regressions on natural log-transformed mean mass recover significant correlations between increasing mass and geological time. However, tests for directional evolution in body mass find no support for a phylogenetic trend, instead favouring passive models of trait evolution. Cross-correlation of sympatric taxa from five localities in Asia reveals that environmental influences such as differential habitat sampling and/or taphonomic filtering affect the preserved record of dinosaurian body mass in the Cretaceous. Our results are congruent with studies documenting that behavioural and/or ecological factors may mitigate the benefit of increasing mass in extant taxa, and suggest that the hypothesis can be extrapolated to herbivorous lineages across geological time scales.

  20. Tetradactyl footprints of an unknown affinity theropod dinosaur from the Upper Jurassic of Morocco.

    Directory of Open Access Journals (Sweden)

    Jaouad Nouri

    Full Text Available BACKGROUND: New tetradactyl theropod footprints from Upper Jurassic (Oxfordian-Kimmeridgian have been found in the Iouaridène syncline (Morocco. The tracksites are at several layers in the intermediate lacustrine unit of Iouaridène Formation. The footprints were named informally in previous works "Eutynichnium atlasipodus". We consider as nomen nudum. METHODOLOGY/PRINCIPAL FINDINGS: Boutakioutichnium atlasicus ichnogen. et ichnosp. nov. is mainly characterized by the hallux impression. It is long, strong, directed medially or forward, with two digital pads and with the proximal part of the first pad in lateral position. More than 100 footprints in 15 trackways have been studied with these features. The footprints are large, 38-48 cm in length, and 26-31 cm in width. CONCLUSIONS/SIGNIFICANCE: Boutakioutichnium mainly differs from other ichnotaxa with hallux impression in lacking metatarsal marks and in not being a very deep footprint. The distinct morphology of the hallux of the Boutakioutichnium trackmaker -i.e. size and hallux position- are unique in the dinosaur autopodial record to date.

  1. Conference Interpreters

    DEFF Research Database (Denmark)

    Leal Lobato, Ana Isabel

    2017-01-01

    Conference Interpreters: How to serve the cause of minorized communities in the new postmonolingual / ‘postmonodiscoursive’ order,......Conference Interpreters: How to serve the cause of minorized communities in the new postmonolingual / ‘postmonodiscoursive’ order,...

  2. Interpretive Journalism

    OpenAIRE

    Salgado, Susana; Strömbäck, Jesper; Aalberg, Toril; Esser, Frank

    2017-01-01

    In summary one-third of the political coverage analyzed in the 16 countries was found to contain interpretive journalism, with some countries - including France and the United States - making use of it much more than the rest. Indeed, the story genres and the interpretive journalism used in the various countries differ substantially, indicating distinct motives and news cultures. A multivariate analysis conducted to identify the most powerful predictors of interpretive journ...

  3. More Adults Are Walking

    Centers for Disease Control (CDC) Podcasts

    2012-07-31

    This podcast is based on the August 2012 CDC Vital Signs report. While more adults are walking, only half get the recommended amount of physical activity. Listen to learn how communities, employers, and individuals may help increase walking.  Created: 7/31/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/7/2012.

  4. Learning-Walk Continuum

    Science.gov (United States)

    Finch, Peter Dallas

    2010-01-01

    The continuum of learning walks can be viewed in stages with various dimensions including frequency, participants, purpose and the presence of an instructional framework within which the instructional practice is viewed. Steps in the continuum progress as the learning walks are conducted more frequently. One way to ensure this is accomplished is…

  5. walk in CAIRO

    DEFF Research Database (Denmark)

    2011-01-01

    Research-baseret audio walk om revolutionen i Cairo med start på Teater Grob (første version, 2011) og Helsingør Teater (anden version, 2012).......Research-baseret audio walk om revolutionen i Cairo med start på Teater Grob (første version, 2011) og Helsingør Teater (anden version, 2012)....

  6. The evolution of the manus of early theropod dinosaurs is characterized by high inter- and intraspecific variation.

    Science.gov (United States)

    Barta, Daniel E; Nesbitt, Sterling J; Norell, Mark A

    2018-01-01

    The origin of the avian hand, with its reduced and fused carpals and digits, from the five-fingered hands and complex wrists of early dinosaurs represents one of the major transformations of manus morphology among tetrapods. Much attention has been directed to the later part of this transition, from four- to three-fingered taxa. However, earlier anatomical changes may have influenced these later modifications, possibly paving the way for a later frameshift in digit identities. We investigate the five- to four-fingered transition among early dinosaurs, along with changes in carpus morphology. New three-dimensional reconstructions from computed tomography data of the manus of the Triassic and Early Jurassic theropod dinosaurs Coelophysis bauri and Megapnosaurus rhodesiensis are described and compared intra- and interspecifically. Several novel findings emerge from these reconstructions and comparisons, including the first evidence of an ossified centrale and a free intermedium in some C. bauri specimens, as well as confirmation of the presence of a vestigial fifth metacarpal in this taxon. Additionally, a specimen of C. bauri and an unnamed coelophysoid from the Upper Triassic Hayden Quarry, New Mexico, are to our knowledge the only theropods (other than alvarezsaurs and birds) in which all of the distal carpals are completely fused together into a single unit. Several differences between the manus of C. bauri and M. rhodesiensis are also identified. We review the evolution of the archosauromorph manus more broadly in light of these new data, and caution against incorporating carpal characters in phylogenetic analyses of fine-scale relationships of Archosauromorpha, in light of the high degree of observed polymorphism in taxa for which large sample sizes are available, such as the theropod Coelophysis and the sauropodomorph Plateosaurus. We also find that the reduction of the carpus and ultimate loss of the fourth and fifth digits among early dinosaurs did not

  7. Avian-like attributes of a virtual brain model of the oviraptorid theropod Conchoraptor gracilis

    Science.gov (United States)

    Kundrát, Martin

    2007-06-01

    An almost complete adult endoneurocranium of Conchoraptor gracilis Barsbold 1986 (Oviraptoridae; ZPAL MgD-I/95), discovered at the Hermiin Tsav locality (the Upper Cretaceous) in Mongolia, is analyzed. A virtual model of the endoneurocranial cavity was derived from CT scans and represents the most complete maniraptoran endocast to date. It displays reduced olfactory bulbs, large cerebral hemispheres in contact with the expanded cerebellum, an epiphysial projection, optic lobes displaced latero-ventrally, presumptive cerebellar folia, enlarged cerebellar auricles, and a deep medulla oblongata with a prominent ventral flexure. Contrary to Archaeopteryx, the shortened olfactory tract and cerebellum overtopping cerebral hemispheres of Conchoraptor resemble conditions in modern birds. Calculating brain mass relative to body mass indicates that Conchoraptor falls within the range of extant birds, whereas Archaeopteryx occupies a marginal position. Most of the endoneurocranial attributes, however, have a less birdlike appearance in Conchoraptor than do corresponding structures in Archaeopteryx and modern birds in which 1) postero-laterally expanded hemispheral domains broadly overlap the optic lobes, 2) the epiphysis projects to the posterior cerebrum, 3) lateral extension of the optic lobes substantially decreases a brain length-to-width ratio, 4) optic lobe and anterior hindbrain are superposed in lateral view, and 5) cerebellar and midbrain compartments are in distinct superposition. The endoneurocranial characteristics of Conchoraptor, taken together, suggest that the animal had a keen sense of vision, balance, and coordination. The data presented in this study do not allow an unambiguous assessment whether the avian-like endoneurocranial characteristics of the flightless Conchoraptor evolved convergently to those of avian theropods, or indicate a derivation of oviraptorosaurs from volant ancestors.

  8. Lévy walks

    Science.gov (United States)

    Zaburdaev, V.; Denisov, S.; Klafter, J.

    2015-04-01

    Random walk is a fundamental concept with applications ranging from quantum physics to econometrics. Remarkably, one specific model of random walks appears to be ubiquitous across many fields as a tool to analyze transport phenomena in which the dispersal process is faster than dictated by Brownian diffusion. The Lévy-walk model combines two key features, the ability to generate anomalously fast diffusion and a finite velocity of a random walker. Recent results in optics, Hamiltonian chaos, cold atom dynamics, biophysics, and behavioral science demonstrate that this particular type of random walk provides significant insight into complex transport phenomena. This review gives a self-consistent introduction to Lévy walks, surveys their existing applications, including latest advances, and outlines further perspectives.

  9. Biomechanical analysis of rollator walking

    DEFF Research Database (Denmark)

    Alkjaer, T; Larsen, Peter K; Pedersen, Gitte

    2006-01-01

    The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects.......The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects....

  10. Environmental factors influencing older adults' walking for transportation: a study using walk-along interviews.

    Science.gov (United States)

    Van Cauwenberg, Jelle; Van Holle, Veerle; Simons, Dorien; Deridder, Riet; Clarys, Peter; Goubert, Liesbet; Nasar, Jack; Salmon, Jo; De Bourdeaudhuij, Ilse; Deforche, Benedicte

    2012-07-10

    Current knowledge on the relationship between the physical environment and walking for transportation among older adults (≥ 65 years) is limited. Qualitative research can provide valuable information and inform further research. However, qualitative studies are scarce and fail to include neighborhood outings necessary to study participants' experiences and perceptions while interacting with and interpreting the local social and physical environment. The current study sought to uncover the perceived environmental influences on Flemish older adults' walking for transportation. To get detailed and context-sensitive environmental information, it used walk-along interviews. Purposeful convenience sampling was used to recruit 57 older adults residing in urban or semi-urban areas. Walk-along interviews to and from a destination (e.g. a shop) located within a 15 minutes' walk from the participants' home were conducted. Content analysis was performed using NVivo 9 software (QSR International). An inductive approach was used to derive categories and subcategories from the data. Data were categorized in the following categories and subcategories: access to facilities (shops & services, public transit, connectivity), walking facilities (sidewalk quality, crossings, legibility, benches), traffic safety (busy traffic, behavior of other road users), familiarity, safety from crime (physical factors, other persons), social contacts, aesthetics (buildings, natural elements, noise & smell, openness, decay) and weather. The findings indicate that to promote walking for transportation a neighborhood should provide good access to shops and services, well-maintained walking facilities, aesthetically appealing places, streets with little traffic and places for social interaction. In addition, the neighborhood environment should evoke feelings of familiarity and safety from crime. Future quantitative studies should investigate if (changes in) these environmental factors relate to

  11. Alzheimer random walk

    Science.gov (United States)

    Odagaki, Takashi; Kasuya, Keisuke

    2017-09-01

    Using the Monte Carlo simulation, we investigate a memory-impaired self-avoiding walk on a square lattice in which a random walker marks each of sites visited with a given probability p and makes a random walk avoiding the marked sites. Namely, p = 0 and p = 1 correspond to the simple random walk and the self-avoiding walk, respectively. When p> 0, there is a finite probability that the walker is trapped. We show that the trap time distribution can well be fitted by Stacy's Weibull distribution b(a/b){a+1}/{b}[Γ({a+1}/{b})]-1x^a\\exp(-a/bx^b)} where a and b are fitting parameters depending on p. We also find that the mean trap time diverges at p = 0 as p- α with α = 1.89. In order to produce sufficient number of long walks, we exploit the pivot algorithm and obtain the mean square displacement and its Flory exponent ν(p) as functions of p. We find that the exponent determined for 1000 step walks interpolates both limits ν(0) for the simple random walk and ν(1) for the self-avoiding walk as [ ν(p) - ν(0) ] / [ ν(1) - ν(0) ] = pβ with β = 0.388 when p ≪ 0.1 and β = 0.0822 when p ≫ 0.1. Contribution to the Topical Issue "Continuous Time Random Walk Still Trendy: Fifty-year History, Current State and Outlook", edited by Ryszard Kutner and Jaume Masoliver.

  12. Interpretation miniatures

    Science.gov (United States)

    Nikolić, Hrvoje

    Most physicists do not have patience for reading long and obscure interpretation arguments and disputes. Hence, to attract attention of a wider physics community, in this paper various old and new aspects of quantum interpretations are explained in a concise and simple (almost trivial) form. About the “Copenhagen” interpretation, we note that there are several different versions of it and explain how to make sense of “local nonreality” interpretation. About the many-world interpretation (MWI), we explain that it is neither local nor nonlocal, that it cannot explain the Born rule, that it suffers from the preferred basis problem, and that quantum suicide cannot be used to test it. About the Bohmian interpretation, we explain that it is analogous to dark matter, use it to explain that there is no big difference between nonlocal correlation and nonlocal causation, and use some condensed-matter ideas to outline how nonrelativistic Bohmian theory could be a theory of everything. We also explain how different interpretations can be used to demystify the delayed choice experiment, to resolve the problem of time in quantum gravity, and to provide alternatives to quantum nonlocality. Finally, we explain why is life compatible with the second law.

  13. A new theropod dinosaur from India with remarks on the Gondwana-Laurasia connection in the Late Triassic

    Science.gov (United States)

    Chatterjee, S.

    Walkeria maleriensis (n. g., n. sp.) from the Late Triassic Maleri Formation of the Godavari Valley of India is the earliest known dinosaur from Asia. It is a small podokesaurid theropod, very similar to Procompsognathus of Germany, Coelophysis of North America, and Syntarsus from Zimbabwe and North America. The podokesaurs are of particular interest to students of organic evolution because they are the earliest known theropods from which Archaeopteryx, the oldest known fossil bird, was probably evolved. Traditionally, India has been regarded as a part of Gondwana. It is generally believed that Gondwana remained an integral geographic unit throughout the Triassic. If this is so, a strong faunal correlation between India and other Gondwana continents should be expected in Late Triassic time. Contrary to this, the Maleri fauna is overwhelmingly "northern". Walkeria occurs in association with metoposaurs, parasuchids, protorosaurs, aetosaurs, rhynchosaurs, and traversodonts. Most of these taxa have been identified in the Dockum fauna of North America, indicating a close paleontologic link between India and Laurasia. Possibly the route of faunal migration between India and North America during the Late Triassic was via northern Africa.

  14. Functional variation of neck muscles and their relation to feeding style in Tyrannosauridae and other large theropod dinosaurs.

    Science.gov (United States)

    Snively, Eric; Russell, Anthony P

    2007-08-01

    Reconstructed neck muscles of large theropod dinosaurs suggest influences on feeding style that paralleled variation in skull mechanics. In all examined theropods, the head dorsiflexor m. transversospinalis capitis probably filled in the posterior dorsal concavity of the neck, for a more crocodilian- than avian-like profile in this region. The tyrannosaurine tyrannosaurids Daspletosaurus and Tyrannosaurus had relatively larger moment arms for latero-flexion by m. longissimus capitis superficialis and m. complexus than albertosaurine tyrannosaurids, and longer dorsiflexive moment arms for m. complexus. Areas of dorsiflexor origination are significantly larger relative to neck length in adult Tyrannosaurus rex than in other tyrannosaurids, suggesting relatively large muscle cross-sections and forces. Tyrannosaurids were not particularly specialized for neck ventro-flexion. In contrast, the hypothesis that Allosaurus co-opted m. longissimus capitis superficialis for ventro-flexion is strongly corroborated. Ceratosaurus had robust insertions for the ventro-flexors m. longissimus capitis profundus and m. rectus capitis ventralis. Neck muscle morphology is consistent with puncture-and-pull and powerful shake feeding in tyrannosaurids, relatively rapid strikes in Allosaurus and Ceratosaurus, and ventroflexive augmentation of weaker jaw muscle forces in the non tyrannosaurids. (c) 2007 Wiley-Liss, Inc.

  15. Record-Breaking Pain: The Largest Number and Variety of Forelimb Bone Maladies in a Theropod Dinosaur.

    Directory of Open Access Journals (Sweden)

    Phil Senter

    Full Text Available Bone abnormalities are common in theropod dinosaur skeletons, but before now no specimen was known with more than four afflicted bones of the pectoral girdle and/or forelimb. Here we describe the pathology of a specimen of the theropod dinosaur Dilophosaurus wetherilli with eight afflicted bones of the pectoral girdle and forelimb. On its left side the animal has a fractured scapula and radius and large fibriscesses in the ulna and the proximal thumb phalanx. On its right side the animal has abnormal torsion of the humeral shaft, bony tumors on the radius, a truncated distal articular surface of metacarpal III, and angular deformities of the first phalanx of the third finger. Healing and remodeling indicates that the animal survived for months and possibly years after its ailments began, but its right third finger was permanently deformed and lacked the capability of flexion. The deformities of the humerus and the right third finger may be due to developmental osteodysplasia, a condition known in extant birds but unreported in non-avian dinosaurs before now.

  16. Record-Breaking Pain: The Largest Number and Variety of Forelimb Bone Maladies in a Theropod Dinosaur.

    Science.gov (United States)

    Senter, Phil; Juengst, Sara L

    2016-01-01

    Bone abnormalities are common in theropod dinosaur skeletons, but before now no specimen was known with more than four afflicted bones of the pectoral girdle and/or forelimb. Here we describe the pathology of a specimen of the theropod dinosaur Dilophosaurus wetherilli with eight afflicted bones of the pectoral girdle and forelimb. On its left side the animal has a fractured scapula and radius and large fibriscesses in the ulna and the proximal thumb phalanx. On its right side the animal has abnormal torsion of the humeral shaft, bony tumors on the radius, a truncated distal articular surface of metacarpal III, and angular deformities of the first phalanx of the third finger. Healing and remodeling indicates that the animal survived for months and possibly years after its ailments began, but its right third finger was permanently deformed and lacked the capability of flexion. The deformities of the humerus and the right third finger may be due to developmental osteodysplasia, a condition known in extant birds but unreported in non-avian dinosaurs before now.

  17. Objective interpretation as conforming interpretation

    Directory of Open Access Journals (Sweden)

    Lidka Rodak

    2011-12-01

    Full Text Available The practical discourse willingly uses the formula of “objective interpretation”, with no regards to its controversial nature that has been discussed in literature.The main aim of the article is to investigate what “objective interpretation” could mean and how it could be understood in the practical discourse, focusing on the understanding offered by judicature.The thesis of the article is that objective interpretation, as identified with textualists’ position, is not possible to uphold, and should be rather linked with conforming interpretation. And what this actually implies is that it is not the virtue of certainty and predictability – which are usually associated with objectivity- but coherence that makes the foundation of applicability of objectivity in law.What could be observed from the analyses, is that both the phenomenon of conforming interpretation and objective interpretation play the role of arguments in the interpretive discourse, arguments that provide justification that interpretation is not arbitrary or subjective. With regards to the important part of the ideology of legal application which is the conviction that decisions should be taken on the basis of law in order to exclude arbitrariness, objective interpretation could be read as a question “what kind of authority “supports” certain interpretation”? that is almost never free of judicial creativity and judicial activism.One can say that, objective and conforming interpretation are just another arguments used in legal discourse.

  18. When Human Walking is a Random Walk

    Science.gov (United States)

    Hausdorff, J. M.

    1998-03-01

    The complex, hierarchical locomotor system normally does a remarkable job of controlling an inherently unstable, multi-joint system. Nevertheless, the stride interval --- the duration of a gait cycle --- fluctuates from one stride to the next, even under stationary conditions. We used random walk analysis to study the dynamical properties of these fluctuations under normal conditions and how they change with disease and aging. Random walk analysis of the stride-to-stride fluctuations of healthy, young adult men surprisingly reveals a self-similar pattern: fluctuations at one time scale are statistically similar to those at multiple other time scales (Hausdorff et al, J Appl Phsyiol, 1995). To study the stability of this fractal property, we analyzed data obtained from healthy subjects who walked for 1 hour at their usual pace, as well as at slower and faster speeds. The stride interval fluctuations exhibited long-range correlations with power-law decay for up to a thousand strides at all three walking rates. In contrast, during metronomically-paced walking, these long-range correlations disappeared; variations in the stride interval were uncorrelated and non-fractal (Hausdorff et al, J Appl Phsyiol, 1996). To gain insight into the mechanism(s) responsible for this fractal property, we examined the effects of aging and neurological impairment. Using detrended fluctuation analysis (DFA), we computed α, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. α was significantly lower in healthy elderly subjects compared to young adults (p < .003) and in subjects with Huntington's disease, a neuro-degenerative disorder of the central nervous system, compared to disease-free controls (p < 0.005) (Hausdorff et al, J Appl Phsyiol, 1997). α was also significantly related to degree of functional impairment in subjects with Huntington's disease (r=0.78). Recently, we have observed that just as

  19. Interpretive Experiments

    Science.gov (United States)

    DeHaan, Frank, Ed.

    1977-01-01

    Describes an interpretative experiment involving the application of symmetry and temperature-dependent proton and fluorine nmr spectroscopy to the solution of structural and kinetic problems in coordination chemistry. (MLH)

  20. Telling Apart Ornithopod and Theropod Trackways : A Closer Look at a Large, Late Jurassic Tridactyl Dinosaur Trackway at Serwah, Republic of Yemen

    NARCIS (Netherlands)

    Schulp, Anne S.; Al-Wosabi, Mohammed

    2012-01-01

    A large bipedal tridactyl dinosaur trackway from the Late Jurassic of Serwah, near Madar, Arhab district, Republic of Yemen, has been attributed to an ornithopod trackmaker. As the distinction between theropod and ornithopod dinosaurs can pose a challenge, we present additional data to support and

  1. Reanalysis of Wupus agilis (Early Cretaceous) of Chongqing, China as a Large Avian Trace: Differentiating between Large Bird and Small Non-Avian Theropod Tracks.

    Science.gov (United States)

    Xing, Lida; Buckley, Lisa G; McCrea, Richard T; Lockley, Martin G; Zhang, Jianping; Piñuela, Laura; Klein, Hendrik; Wang, Fengping

    2015-01-01

    Trace fossils provide the only records of Early Cretaceous birds from many parts of the world. The identification of traces from large avian track-makers is made difficult given their overall similarity in size and tridactyly in comparison with traces of small non-avian theropods. Reanalysis of Wupus agilis from the Early Cretaceous (Aptian-Albian) Jiaguan Formation, one of a small but growing number of known avian-pterosaur track assemblages, of southeast China determines that these are the traces of a large avian track-maker, analogous to extant herons. Wupus, originally identified as the trace of a small non-avian theropod track-maker, is therefore similar in both footprint and trackway characteristics to the Early Cretaceous (Albian) large avian trace Limiavipes curriei from western Canada, and Wupus is reassigned to the ichnofamily Limiavipedidae. The reanalysis of Wupus reveals that it and Limiavipes are distinct from similar traces of small to medium-sized non-avian theropods (Irenichnites, Columbosauripus, Magnoavipes) based on their relatively large footprint length to pace length ratio and higher mean footprint splay, and that Wupus shares enough characters with Limiavipes to be reassigned to the ichnofamily Limiavipedidae. The ability to discern traces of large avians from those of small non-avian theropods provides more data on the diversity of Early Cretaceous birds. This analysis reveals that, despite the current lack of body fossils, large wading birds were globally distributed in both Laurasia and Gondwana during the Early Cretaceous.

  2. Reanalysis of Wupus agilis (Early Cretaceous of Chongqing, China as a Large Avian Trace: Differentiating between Large Bird and Small Non-Avian Theropod Tracks.

    Directory of Open Access Journals (Sweden)

    Lida Xing

    Full Text Available Trace fossils provide the only records of Early Cretaceous birds from many parts of the world. The identification of traces from large avian track-makers is made difficult given their overall similarity in size and tridactyly in comparison with traces of small non-avian theropods. Reanalysis of Wupus agilis from the Early Cretaceous (Aptian-Albian Jiaguan Formation, one of a small but growing number of known avian-pterosaur track assemblages, of southeast China determines that these are the traces of a large avian track-maker, analogous to extant herons. Wupus, originally identified as the trace of a small non-avian theropod track-maker, is therefore similar in both footprint and trackway characteristics to the Early Cretaceous (Albian large avian trace Limiavipes curriei from western Canada, and Wupus is reassigned to the ichnofamily Limiavipedidae. The reanalysis of Wupus reveals that it and Limiavipes are distinct from similar traces of small to medium-sized non-avian theropods (Irenichnites, Columbosauripus, Magnoavipes based on their relatively large footprint length to pace length ratio and higher mean footprint splay, and that Wupus shares enough characters with Limiavipes to be reassigned to the ichnofamily Limiavipedidae. The ability to discern traces of large avians from those of small non-avian theropods provides more data on the diversity of Early Cretaceous birds. This analysis reveals that, despite the current lack of body fossils, large wading birds were globally distributed in both Laurasia and Gondwana during the Early Cretaceous.

  3. Walking - Sensing - Participation

    DEFF Research Database (Denmark)

    Bødker, Mads; Meinhardt, Nina Dam; Browning, David

    2014-01-01

    Building on ethnographic research and social theory in the field of ‘mobilities’, this workshop paper suggests that field work based on simply walking with people entails a form of embodied participation that informs technological interventions by creating a space within which to address a wider ...... set of experiential or ‘felt’ qualities of living with mobile technologies. Moving from reflections on the value of walking with people, the paper outlines some affordances of a smartphone application built to capture place experiences through walking.......Building on ethnographic research and social theory in the field of ‘mobilities’, this workshop paper suggests that field work based on simply walking with people entails a form of embodied participation that informs technological interventions by creating a space within which to address a wider...

  4. Minimal Walking Technicolor

    DEFF Research Database (Denmark)

    Foadi, Roshan; Frandsen, Mads Toudal; A. Ryttov, T.

    2007-01-01

    Different theoretical and phenomenological aspects of the Minimal and Nonminimal Walking Technicolor theories have recently been studied. The goal here is to make the models ready for collider phenomenology. We do this by constructing the low energy effective theory containing scalars, pseudoscal......Different theoretical and phenomenological aspects of the Minimal and Nonminimal Walking Technicolor theories have recently been studied. The goal here is to make the models ready for collider phenomenology. We do this by constructing the low energy effective theory containing scalars......, pseudoscalars, vector mesons and other fields predicted by the minimal walking theory. We construct their self-interactions and interactions with standard model fields. Using the Weinberg sum rules, opportunely modified to take into account the walking behavior of the underlying gauge theory, we find...

  5. Walking wisely: Sapiential influence in Psalm 26

    Directory of Open Access Journals (Sweden)

    Annette Potgieter

    2013-05-01

    Full Text Available Psalm 26 is interpreted by the majority of scholars as a cultic psalm. This has limited research on Psalm 26. There are clear traces of sapiential influence in Psalm 26 concerning its intricately well-thought concentric structure as well as various wisdom connections. This study will however focus on the structure as well as on the core wisdom theme of walking the way of Yahweh. This opens up interpretation possibilities for Psalm 26 and it also indicates that Psalm 26 is a literary creation belonging to the Persian Period.

  6. Walking the Everyday

    Directory of Open Access Journals (Sweden)

    Matthew Bissen

    2014-11-01

    Full Text Available Since 2010, @matthewalking (Bissen, 2013 has published real-time public texts of walks in the city. This text-based Twitter feed has developed a narrative of a particular everyday life and developed a space of interface with others that represents a centering of perspective within an urban landscape. Walking the city provides a spatial, tactile, social, and embodied knowledge of the environment as each of us emerges into a space, orients ourselves, and determines a path that is highly localized, but is in connection with distant spaces and cultures. According to Ben Jacks in “Walking the City: Manhattan Projects,” “for urban dwellers and designers, walking is a fundamental tool for laying claim to, understanding, and shaping a livable city. Walking yields bodily knowing, recovers place memory, creates narrative, prioritizes human scale, and reconnects people to places” (75. @matthewalking’s walks, at times for as long as 5 hours, attempt to center an experience of an urban existence in a spatial narrative of the city that at once prioritizes a connection to place, but also is projected outward into a mediated relationship with others. The project is a series of unbounded walks, or dérives (drift, through the city that are logged on Twitter and traced to create an archive map of a set of particular urban experiences. The dérive concept as outlined in “The Theory of the Dérive,” by Guy Debord is when “one or more persons during a certain period drop their relations, their work and leisure activities, and all their other usual motives for movement and action, and let themselves be drawn by the attractions of the terrain and the encounters they find there” (62.

  7. How does wearable robotic exoskeleton affect overground walking performance measured with the 10-m and six-minute walk tests after a basic locomotor training in healthy individuals?

    Science.gov (United States)

    Gagnon, Dany H; Cunha, Jérémie Da; Boyer-Delestre, Mael; Bosquet, Laurent; Duclos, Cyril

    2017-10-01

    It is still unknown to what extent overground walking with a WRE is equivalent to natural overground walking without a WRE. Hence, the interpretability of the 10-m (10MWT) and six-minute (6MWT) walk tests during overground walking with a WRE against reference values collected during natural overground walking without a WRE is challenging. This study aimed to 1) compare walking performance across three different overground walking conditions: natural walking without a WRE, walking with a WRE providing minimal assistance (active walking), and walking with a WRE proving complete assistance (passive walking) and 2) assess the association and the agreement between the 10MWT and the 6MWT during passive and active walking with a WRE. Seventeen healthy individuals who underwent basic locomotor training with a WRE performed the 10MWT (preferred and maximal speeds) and the 6MWT under the three conditions. For the 10MWT, the speed progressively and significantly decreased from natural walking without a WRE (preferred: 1.40±0.18m/s; maximal: 2.16±0.19m/s), to active walking with a WRE (preferred: 0.48±0.10m/s; maximal: 0.61±0.14m/s), and to passive walking with a WRE (preferred: 0.38±0.09m/s; maximal: 0.42±0.10m/s). For the 6MWT, total distances decreased from walking without a WRE (609±53.9m), to active walking with a WRE (196.6±42.6m), and to passive walking with a WRE (144.3±33.3m). The 10MWT and 6MWT provide distinct information and can't be used interchangeably to document speed only during active walking with the WRE. Speed and distance drastically decrease during active and, even more so, passive walking with the WRE in comparison to walking without a WRE. Selection of walking tests should depend on the level of assistance provided by the WRE. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Interpreting Physics

    CERN Document Server

    MacKinnon, Edward

    2012-01-01

    This book is the first to offer a systematic account of the role of language in the development and interpretation of physics. An historical-conceptual analysis of the co-evolution of mathematical and physical concepts leads to the classical/quatum interface. Bohrian orthodoxy stresses the indispensability of classical concepts and the functional role of mathematics. This book analyses ways of extending, and then going beyond this orthodoxy orthodoxy. Finally, the book analyzes how a revised interpretation of physics impacts on basic philosophical issues: conceptual revolutions, realism, and r

  9. Walking With Death, Walking With Science, Walking With Living: Philosophical Praxis and Happiness

    Directory of Open Access Journals (Sweden)

    Frances Gray

    2006-01-01

    Full Text Available This paper explores the consequences of acknowledging that we are the dead walking with the dead. I argue that if we take the view that life frames death, rather than the view that death frames life, then we must refigure our living as ethical creatures. Using Aristotle's notion that we become virtuous by practising virtue, I argue that happiness, thought of in terms of ethical living, should temper our attitude to death as the inevitable end we must all encounter. Acknowledgement of our dying and our death enhances the ethical imperative to live virtuously and to promote human flourishing. I adopt a Buddhist reading of death and dying to interpret the Aristotelian perspective.

  10. Walking With Death, Walking With Science, Walking With Living: Philosophical Praxis and Happiness

    Directory of Open Access Journals (Sweden)

    Frances Gray

    2005-01-01

    Full Text Available This paper explores the consequences of acknowledging that we are the dead walking with the dead. I argue that if we take the view that life frames death, rather than the view that death frames life, then we must refigure our living as ethical creatures. Using Aristotle's notion that we become virtuous by practising virtue, I argue that happiness, thought of in terms of ethical living, should temper our attitude to death as the inevitable end we must all encounter. Acknowledgement of our dying and our death enhances the ethical imperative to live virtuously and to promote human flourishing. I adopt a Buddhist reading of death and dying to interpret the Aristotelian perspective.

  11. Unitary equivalence of quantum walks

    International Nuclear Information System (INIS)

    Goyal, Sandeep K.; Konrad, Thomas; Diósi, Lajos

    2015-01-01

    Highlights: • We have found unitary equivalent classes in coined quantum walks. • A single parameter family of coin operators is sufficient to realize all simple one-dimensional quantum walks. • Electric quantum walks are unitarily equivalent to time dependent quantum walks. - Abstract: A simple coined quantum walk in one dimension can be characterized by a SU(2) operator with three parameters which represents the coin toss. However, different such coin toss operators lead to equivalent dynamics of the quantum walker. In this manuscript we present the unitary equivalence classes of quantum walks and show that all the nonequivalent quantum walks can be distinguished by a single parameter. Moreover, we argue that the electric quantum walks are equivalent to quantum walks with time dependent coin toss operator

  12. A THEROPOD DOMINATED ICHNOCOENOSIS FROM LATE HAUTERIVIAN-EARLYBARREMIAN OF BORGO CELANO (GARGANO PROMONTORY, APULIA, SOUTHERN ITALY

    Directory of Open Access Journals (Sweden)

    FABIO MASSIMO PETTI

    2008-03-01

    Full Text Available Several dinosaur footprints were discovered on three different levels cropping out in the CO.L.MAR quarry, south of the village of Borgo Celano in the Gargano Promontory (Apulia, southern Italy. The track-bearing levels belong to a carbonate inner platform succession referred to the Lower Cretaceous (upper Hauterivian-lower Barremian. This paper describes only the lowest dinoturbated bed, where footprints are preserved as natural cast. Forty footprints, mostly tridactyl, have been attributed to medium-sized theropods. Tridactyl tracks are similar to Kayentapus Welles, 1971 regarding ichnotaxonomy. Round shaped footprints, previously not described from this site, are found in association with tridactyl footprints and are related to ornitischian dinosaurs. 

  13. New information on Nqwebasaurus thwazi, a coelurosaurian theropod from the Early Cretaceous Kirkwood Formation in South Africa

    Science.gov (United States)

    Choiniere, Jonah N.; Forster, Catherine A.; de Klerk, William J.

    2012-08-01

    We performed additional preparation on the holotype skeleton of Nqwebasaurus thwazi and discovered new skeletal material. We describe this material, which includes a maxilla with small, conical, unserrated teeth and bones of the braincase, as well as parts of the holotype postcranial anatomy that were previously poorly documented. We incorporate this new anatomical information into a broadly sampled matrix designed to test theropod relationships. Our phylogenetic results hypothesize that Nqwebasaurus is the basalmost ornithomimosaur, and recover numerous characters supporting this relationship, including features of the maxilla, frontal, dentition, axial skeleton, forelimb and hindlimb. Nqwebasaurus is the first African ornithomimosaur and the first Gondwanan member of this group known from articulated skeletal material, supporting the hypothesis that coelurosaurian groups were cosmopolitan during their early evolutionary history. The presence of reduced dentition and a gastric mill in Nqwebasaurus strongly suggest that this taxon was herbivorous.

  14. Walks on SPR neighborhoods.

    Science.gov (United States)

    Caceres, Alan Joseph J; Castillo, Juan; Lee, Jinnie; St John, Katherine

    2013-01-01

    A nearest-neighbor-interchange (NNI)-walk is a sequence of unrooted phylogenetic trees, T1, T2, . . . , T(k) where each consecutive pair of trees differs by a single NNI move. We give tight bounds on the length of the shortest NNI-walks that visit all trees in a subtree-prune-and-regraft (SPR) neighborhood of a given tree. For any unrooted, binary tree, T, on n leaves, the shortest walk takes Θ(n²) additional steps more than the number of trees in the SPR neighborhood. This answers Bryant’s Second Combinatorial Challenge from the Phylogenetics Challenges List, the Isaac Newton Institute, 2011, and the Penny Ante Problem List, 2009.

  15. Ways of Walking

    DEFF Research Database (Denmark)

    Eslambolchilar, Parisa; Bødker, Mads; Chamberlain, Alan

    2016-01-01

    technologies. Drawing on insights from non-representational theory, we develop a partial vocabulary with which to engage with qualities of pedestrian mobility, and we outline how taking more mindful approaches to walking may enrich and inform the design space of handheld technologies.......It seems logical to argue that mobile computing technologies are intended for use "on-the-go." However, on closer inspection, the use of mobile technologies pose a number of challenges for users who are mobile, particularly moving around on foot. In engaging with such mobile technologies...... and their envisaged development, we argue that interaction designers must increasingly consider a multitude of perspectives that relate to walking in order to frame design problems appropriately. In this paper, we consider a number of perspectives on walking, and we discuss how these may inspire the design of mobile...

  16. Walking for data

    DEFF Research Database (Denmark)

    Bødker, Mads; Browning, David; Meinhardt, Nina Dam

    We suggest that ‘walking’ in ethnographic work sensitizes researchers to a particular means of making sense of place. Following a brief conceptual exposition, we present our research tool iMaCam) that supports capturing and representing activities such as walking.......We suggest that ‘walking’ in ethnographic work sensitizes researchers to a particular means of making sense of place. Following a brief conceptual exposition, we present our research tool iMaCam) that supports capturing and representing activities such as walking....

  17. Minimal Walking Technicolor

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal

    2007-01-01

    I report on our construction and analysis of the effective low energy Lagrangian for the Minimal Walking Technicolor (MWT) model. The parameters of the effective Lagrangian are constrained by imposing modified Weinberg sum rules and by imposing a value for the S parameter estimated from the under......I report on our construction and analysis of the effective low energy Lagrangian for the Minimal Walking Technicolor (MWT) model. The parameters of the effective Lagrangian are constrained by imposing modified Weinberg sum rules and by imposing a value for the S parameter estimated from...

  18. Fitness Club / Nordic Walking

    CERN Multimedia

    Fitness Club

    2011-01-01

    Nordic Walking at CERN Enrollments are open for Nordic Walking courses and outings at CERN. Classes will be on Tuesdays as of 20 September, and outings for the more experienced will be on Thursdays as of 15 September. We meet at the CERN Club barracks car park (near entrance A). • 18:00 to 19:00 on 20 & 27 September, as well as 4 & 11 October. Check out our schedule and rates and enroll at: http://cern.ch/club-fitness Hope to see you among us! CERN Fitness Club fitness.club@cern.ch  

  19. Sunspot random walk and 22-year variation

    Science.gov (United States)

    Love, Jeffrey J.; Rigler, E. Joshua

    2012-01-01

    We examine two stochastic models for consistency with observed long-term secular trends in sunspot number and a faint, but semi-persistent, 22-yr signal: (1) a null hypothesis, a simple one-parameter random-walk model of sunspot-number cycle-to-cycle change, and, (2) an alternative hypothesis, a two-parameter random-walk model with an imposed 22-yr alternating amplitude. The observed secular trend in sunspots, seen from solar cycle 5 to 23, would not be an unlikely result of the accumulation of multiple random-walk steps. Statistical tests show that a 22-yr signal can be resolved in historical sunspot data; that is, the probability is low that it would be realized from random data. On the other hand, the 22-yr signal has a small amplitude compared to random variation, and so it has a relatively small effect on sunspot predictions. Many published predictions for cycle 24 sunspots fall within the dispersion of previous cycle-to-cycle sunspot differences. The probability is low that the Sun will, with the accumulation of random steps over the next few cycles, walk down to a Dalton-like minimum. Our models support published interpretations of sunspot secular variation and 22-yr variation resulting from cycle-to-cycle accumulation of dynamo-generated magnetic energy.

  20. Physiological aspect walking and Nordic walking as adequate kinetic activities.

    OpenAIRE

    BENEŠ, Václav

    2010-01-01

    This bachelor thesis on the topic of The Physiological Aspect of Walking and Nordic Walking as an adequate physical activity focuses on chosen physiological changes of an organism during a five-month training cycle. In the theoretical part I describe the physiological changes of organism during a regularly repeated strain, and also the technique of walking, Nordic walking and health benefits of these activities are defined here. The research part of the thesis describes the measurement method...

  1. 10 CFR 431.302 - Definitions concerning walk-in coolers and walk-in freezers.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning walk-in coolers and walk-in... FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers § 431.302 Definitions concerning walk-in coolers and walk-in freezers. Walk-in cooler and walk-in freezer mean an...

  2. Interpretive Medicine

    Science.gov (United States)

    Reeve, Joanne

    2010-01-01

    Patient-centredness is a core value of general practice; it is defined as the interpersonal processes that support the holistic care of individuals. To date, efforts to demonstrate their relationship to patient outcomes have been disappointing, whilst some studies suggest values may be more rhetoric than reality. Contextual issues influence the quality of patient-centred consultations, impacting on outcomes. The legitimate use of knowledge, or evidence, is a defining aspect of modern practice, and has implications for patient-centredness. Based on a critical review of the literature, on my own empirical research, and on reflections from my clinical practice, I critique current models of the use of knowledge in supporting individualised care. Evidence-Based Medicine (EBM), and its implementation within health policy as Scientific Bureaucratic Medicine (SBM), define best evidence in terms of an epistemological emphasis on scientific knowledge over clinical experience. It provides objective knowledge of disease, including quantitative estimates of the certainty of that knowledge. Whilst arguably appropriate for secondary care, involving episodic care of selected populations referred in for specialist diagnosis and treatment of disease, application to general practice can be questioned given the complex, dynamic and uncertain nature of much of the illness that is treated. I propose that general practice is better described by a model of Interpretive Medicine (IM): the critical, thoughtful, professional use of an appropriate range of knowledges in the dynamic, shared exploration and interpretation of individual illness experience, in order to support the creative capacity of individuals in maintaining their daily lives. Whilst the generation of interpreted knowledge is an essential part of daily general practice, the profession does not have an adequate framework by which this activity can be externally judged to have been done well. Drawing on theory related to the

  3. Walking along water

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2014-01-01

    Steep slopes, white peaks and deep valleys make up the Andes. As phenomenologists of landscape have told us, different people have different landscapes. By moving across the terrain, walking along, we might get a sense of how this has been carved out by the movement of wind and water, tectonics...

  4. Walking to transit.

    Science.gov (United States)

    2011-12-01

    Using a real-life setting, WalkBostons project focused on developing and testing techniques to broaden the scope and range of public participation in transportation planning in a large neighborhood in Boston. The team explored methods of seeking o...

  5. Walking - Sensing - Participation

    DEFF Research Database (Denmark)

    Bødker, Mads; Meinhardt, Nina Dam; Browning, David

    Building on ethnographic research and social theory in the field of ‘mobilities’, this workshop paper suggests that field work based on simply walking with people entails a form of embodied participation that informs technological interventions by creating a space within which to address a wider...

  6. Walking and Sensing Mobile Lives

    DEFF Research Database (Denmark)

    Bødker, Mads; Meinhardt, Nina Dam

    In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk.......In this position paper, we discuss how mindful walking with people allow us to explore sensory aspects of mobile lives that are typically absent from research. We present an app that aids researchers collect impressions from a walk....

  7. Objective interpretation as conforming interpretation

    OpenAIRE

    Lidka Rodak

    2011-01-01

    The practical discourse willingly uses the formula of “objective interpretation”, with no regards to its controversial nature that has been discussed in literature.The main aim of the article is to investigate what “objective interpretation” could mean and how it could be understood in the practical discourse, focusing on the understanding offered by judicature.The thesis of the article is that objective interpretation, as identified with textualists’ position, is not possible to uphold, and ...

  8. Kineziologická charakteristika Nordic Walking

    OpenAIRE

    Pospíšilová, Petra

    2009-01-01

    Title: Functional a physiological characteristics of Nordic Walking Purposes: The aim of the thesis is to describe and summarize current knowledge about Nordic Walking Methods: Literature analysis Key words: Nordic Walking, free bipedal walk, health benefits, functional indicator changes

  9. Quantum walks induced by Dirichlet random walks on infinite trees

    Science.gov (United States)

    Higuchi, Yusuke; Segawa, Etsuo

    2018-02-01

    We consider the Grover walk on infinite trees from the viewpoint of spectral analysis. From the previous work, infinite regular trees provide localization. In this paper, we give the complete characterization of the eigenspace of this Grover walk, which involves localization of its behavior and recovers the previous work. Our result suggests that the Grover walk on infinite trees may be regarded as a limit of the quantum walk induced by the isotropic random walk with the Dirichlet boundary condition at the n-th depth rather than one with the Neumann boundary condition.

  10. Small Theropod Teeth from the Late Cretaceous of the San Juan Basin, Northwestern New Mexico and Their Implications for Understanding Latest Cretaceous Dinosaur Evolution

    OpenAIRE

    Williamson, Thomas; Brusatte, Steve

    2014-01-01

    Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during th...

  11. Health benefits of Nordic walking: a systematic review.

    Science.gov (United States)

    Tschentscher, Marcus; Niederseer, David; Niebauer, Josef

    2013-01-01

    Modern lifestyle, with its lack of everyday physical activity and exercise training, predisposes people to chronic diseases such as diabetes mellitus, obesity, hypertension, and coronary artery diseases. Brisk walking as a simple and safe form of exercise is undisputedly an effective measure to counteract sedentary lifestyle risks even in the most unfit and could lead to a reduction of the prevalence of chronic diseases in all populations. The purpose of this review is to systematically summarize, analyze, and interpret the health benefits of Nordic walking (walking with poles), and to compare it to brisk walking and jogging. A systematic and comprehensive literature search was performed between November 2010 and May 2012. Data were analyzed between April 2011 and May 2012. Sixteen RCTs with a total of 1062 patients and 11 observational studies with 831 patients were identified. The current analysis revealed that with regard to short- and long-term effects on heart rate, oxygen consumption, quality of life, and other measures, Nordic walking is superior to brisk walking without poles and in some endpoints to jogging. Nordic walking exerts beneficial effects on resting heart rate, blood pressure, exercise capacity, maximal oxygen consumption, and quality of life in patients with various diseases and can thus be recommended to a wide range of people as primary and secondary prevention. Copyright © 2013 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  12. Mammographic interpretation

    International Nuclear Information System (INIS)

    Tabor, L.

    1987-01-01

    For mammography to be an effective diagnostic method, it must be performed to a very high standard of quality. Otherwise many lesions, in particular cancer in its early stages, will simply not be detectable on the films, regardless of the skill of the mammographer. Mammographic interpretation consists of two basic steps: perception and analysis. The process of mammographic interpretation begins with perception of the lesion on the mammogram. Perception is influenced by several factors. One of the most important is the parenchymal pattern of the breast tissue, detection of pathologic lesions being easier with fatty involution. The mammographer should use a method for the systematic viewing of the mammograms that will ensure that all parts of each mammogram are carefully searched for the presence of lesions. The method of analysis proceeds according to the type of lesion. The contour analysis of primary importance in the evaluation of circumscribed tumors. After having analyzed the contour and density of a lesion and considered its size, the mammographer should be fairly certain whether the circumscribed tumor is benign or malignant. Fine-needle puncture and/or US may assist the mammographer in making this decision. Painstaking analysis is required because many circumscribed tumors do not need to be biopsied. The perception of circumscribed tumors seldom causes problems, but their analysis needs careful attention. On the other hand, the major challenge with star-shaped lesions is perception. They may be difficult to discover when small. Although the final diagnosis of a stellate lesion can be made only with the help of histologic examination, the preoperative mammorgraphic differential diagnosis can be highly accurate. The differential diagnostic problem is between malignant tumors (scirrhous carcinoma), on the one hand, and traumatic fat necrosis as well as radial scars on the other hand

  13. Nordic Walking Classes

    CERN Multimedia

    Fitness Club

    2015-01-01

    Four classes of one hour each are held on Tuesdays. RDV barracks parking at Entrance A, 10 minutes before class time. Spring Course 2015: 05.05/12.05/19.05/26.05 Prices 40 CHF per session + 10 CHF club membership 5 CHF/hour pole rental Check out our schedule and enroll at: https://espace.cern.ch/club-fitness/Lists/Nordic%20Walking/NewForm.aspx? Hope to see you among us! fitness.club@cern.ch

  14. An Interpreter's Interpretation: Sign Language Interpreters' View of Musculoskeletal Disorders

    National Research Council Canada - National Science Library

    Johnson, William L

    2003-01-01

    Sign language interpreters are at increased risk for musculoskeletal disorders. This study used content analysis to obtain detailed information about these disorders from the interpreters' point of view...

  15. A history of digit identification in the manus of theropods (including Aves)

    DEFF Research Database (Denmark)

    Hansen, Kasper Lykke

    2010-01-01

    The identification of avian and dinosaurian digits remains one of the major controversies in vertebrate evolution. A long history of morphological interpretations of fossil forms and studies of limb development in embryos has been given as evidence for two differing points of view. From...

  16. A history of digit identification in the manus of theropods (including Aves)

    DEFF Research Database (Denmark)

    Hansen, Kasper Lykke

    2010-01-01

    The identification of avian and dinosaurian digits remains one of the major controversies in vertebrate evolution. A long history of morphological interpretations of fossil forms and studies of limb development in embryos has been given as evidence for two differing points of view. From an origin...

  17. The Random Walk Drainage Simulation Model as a Teaching Exercise

    Science.gov (United States)

    High, Colin; Richards, Paul

    1972-01-01

    Practical instructions about using the random walk drainage network simulation model as a teaching excercise are given and the results discussed. A source of directional bias in the resulting simulated drainage patterns is identified and given an interpretation in the terms of the model. Three points of educational value concerning the model are…

  18. Interpretation training influences memory for prior interpretations

    NARCIS (Netherlands)

    Salemink, E.; Hertel, P.; Mackintosh, B.

    2010-01-01

    Anxiety is associated with memory biases when the initial interpretation of the event is taken into account. This experiment examined whether modification of interpretive bias retroactively affects memory for prior events and their initial interpretation. Before training, participants imagined

  19. An exquisitely preserved troodontid theropod with new information on the palatal structure from the Upper Cretaceous of Mongolia

    Science.gov (United States)

    Tsuihiji, Takanobu; Barsbold, Rinchen; Watabe, Mahito; Tsogtbaatar, Khishigjav; Chinzorig, Tsogtbaatar; Fujiyama, Yoshito; Suzuki, Shigeru

    2014-02-01

    Troodontidae is a clade of small-bodied theropod dinosaurs. A new troodontid, Gobivenator mongoliensis gen. et sp. nov., is described based on the most complete skeleton of a Late Cretaceous member of this clade presently known, from the Campanian Djadokhta Formation in the central Gobi Desert. G. mongoliensis is different from other troodontids in possessing a pointed anterior end of the fused parietal and a fossa on the surangular in front of the posterior surangular foramen. The skull was superbly preserved in the specimen and provides detailed information of the entire configuration of the palate in Troodontidae. Overall morphology of the palate in Gobivenator resembles those of dromaeosaurids and Archaeopteryx, showing an apparent trend of elongation of the pterygoid process of the palatine and reduction of the pterygopalatine suture toward the basal Avialae. The palatal configuration suggests that the skull of Gobivenator would have been akinetic but had already acquired prerequisites for later evolution of cranial kinesis in birds, such as the loss of the epipterygoid and reduction in contact areas among bones.

  20. Fractional random walk lattice dynamics

    Science.gov (United States)

    Michelitsch, T. M.; Collet, B. A.; Riascos, A. P.; Nowakowski, A. F.; Nicolleau, F. C. G. A.

    2017-02-01

    We analyze time-discrete and time-continuous ‘fractional’ random walks on undirected regular networks with special focus on cubic periodic lattices in n  =  1, 2, 3,.. dimensions. The fractional random walk dynamics is governed by a master equation involving fractional powers of Laplacian matrices {{L}\\fracα{2}}} where α =2 recovers the normal walk. First we demonstrate that the interval 0expressions for the transition matrix of the fractional random walk and closely related the average return probabilities. We further obtain the fundamental matrix {{Z}(α )} , and the mean relaxation time (Kemeny constant) for the fractional random walk. The representation for the fundamental matrix {{Z}(α )} relates fractional random walks with normal random walks. We show that the matrix elements of the transition matrix of the fractional random walk exihibit for large cubic n-dimensional lattices a power law decay of an n-dimensional infinite space Riesz fractional derivative type indicating emergence of Lévy flights. As a further footprint of Lévy flights in the n-dimensional space, the transition matrix and return probabilities of the fractional random walk are dominated for large times t by slowly relaxing long-wave modes leading to a characteristic {{t}-\\frac{n{α}} -decay. It can be concluded that, due to long range moves of fractional random walk, a small world property is emerging increasing the efficiency to explore the lattice when instead of a normal random walk a fractional random walk is chosen.

  1. Agile Walking Robot

    Science.gov (United States)

    Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.; Waldron, Kenneth J.

    1990-01-01

    Proposed agile walking robot operates over rocky, sandy, and sloping terrain. Offers stability and climbing ability superior to other conceptual mobile robots. Equipped with six articulated legs like those of insect, continually feels ground under leg before applying weight to it. If leg sensed unexpected object or failed to make contact with ground at expected point, seeks alternative position within radius of 20 cm. Failing that, robot halts, examines area around foot in detail with laser ranging imager, and replans entire cycle of steps for all legs before proceeding.

  2. Physical implementation of quantum walks

    CERN Document Server

    Manouchehri, Kia

    2013-01-01

    Given the extensive application of random walks in virtually every science related discipline, we may be at the threshold of yet another problem solving paradigm with the advent of quantum walks. Over the past decade, quantum walks have been explored for their non-intuitive dynamics, which may hold the key to radically new quantum algorithms. This growing interest has been paralleled by a flurry of research into how one can implement quantum walks in laboratories. This book presents numerous proposals as well as actual experiments for such a physical realization, underpinned by a wide range of

  3. Quantum walks with entangled coins

    International Nuclear Information System (INIS)

    Venegas-Andraca, S E; Ball, J L; Burnett, K; Bose, S

    2005-01-01

    We present a mathematical formalism for the description of un- restricted quantum walks with entangled coins and one walker. The numerical behaviour of such walks is examined when using a Bell state as the initial coin state, with two different coin operators, two different shift operators, and one walker. We compare and contrast the performance of these quantum walks with that of a classical random walk consisting of one walker and two maximally correlated coins as well as quantum walks with coins sharing different degrees of entanglement. We illustrate that the behaviour of our walk with entangled coins can be very different in comparison to the usual quantum walk with a single coin. We also demonstrate that simply by changing the shift operator, we can generate widely different distributions. We also compare the behaviour of quantum walks with maximally entangled coins with that of quantum walks with non-entangled coins. Finally, we show that the use of different shift operators on two and three qubit coins leads to different position probability distributions in one- and two-dimensional graphs

  4. Random-walk enzymes

    Science.gov (United States)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-01-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C → U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics. PMID:26465508

  5. Random-walk enzymes

    Science.gov (United States)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-09-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  6. Walking trajectory in neglect patients

    NARCIS (Netherlands)

    Huitema, RB; Brouwer, WH; Hof, AL; Dekker, R; Mulder, T; Postema, K

    A lateral deviation of the walking trajectory is often observed in stroke patients with unilateral spatial neglect. However, existing research appears to be contradictory regarding the direction of this deviation. The aim of the present study was to gain more insight into the walking trajectory of

  7. Walking for art's sake

    CERN Multimedia

    2005-01-01

      The man who compared himself to a proton ! On 20 May, Gianni Motti went down into the LHC tunnel and walked around the 27 kilometres of the underground ring at an average, unaccelerated pace of 5 kph. This was an artistic rather than an athletic performance, aimed at drawing a parallel between the fantastic speed of the beams produced by the future accelerator and the leisurely stroll of a human. The artist, who hails from Lombardy, was accompanied by cameraman Ivo Zanetti, who filmed the event from start to finish, and physicist Jean-Pierre Merlo. The first part of the film can be seen at the Villa Bernasconi, 8 route du Grand-Lancy, Grand Lancy, until 26 June.

  8. Walking for art's sake

    CERN Multimedia

    2005-01-01

    The man who compared himself to a proton ! On 20 May, Gianni Motti went down into the LHC tunnel and walked around the 27 kilometres of the underground ring at an average, unaccelerated pace of 5 kph. This was an artistic rather than an athletic performance, aimed at drawing a parallel between the fantastic speed of the beams produced by the future accelerator and the leisurely stroll of a human. The artist, who hails from Lombardy, was accompanied by cameraman Ivo Zanetti, who filmed the event from start to finish, and physicist Jean-Pierre Merlo. The first part of the film can be seen at the Villa Bernasconi, 8 route du Grand-Lancy, Grand Lancy, until 26 June.

  9. walk around Irkutsk

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2011-08-01

    Full Text Available It is noteworthy that this country develops through two types of events: either through a jubilee or through a catastrophe.It seems that Irkutsk Airport will be built only after the next crash. At least the interest to this problem returns regularly after sad events, and this occurs almost half a century (a jubilee, too! – the Council of Ministers decided to relocate the Airport away from the city as long ago as 1962. The Airport does not relate to the topic of this issue, but an attentive reader understands that it is our Carthage, and that the Airport should be relocated. The Romans coped with it faster and more effectively.Back to Irkutsk’s jubilee, we should say that we will do without blare of trumpets. We will just make an unpretentious walk around the city in its summer 350. Each our route covers new (some of them have been completed by the jubilee and old buildings, some of them real monuments. All these buildings are integrated into public spaces of different quality and age.We will also touch on the problems, for old houses, especially the wooden ones often provoke a greedy developer to demolish or to burn them down. Thus a primitive thrift estimates an output of additional square meters. Not to mention how attractive it is to seize public spaces without demolition or without reallocation of the dwellers. Or, rather, the one who is to preserve, to cherish and to improve such houses for the good of the citizens never speaks about this sensitive issue. So we have to do it.Walking is a no-hurry genre, unlike the preparation for the celebration. Walking around the city you like is a pleasant and cognitive process. It will acquaint the architects with the works of their predecessors and colleagues. We hope that such a walk may be interesting for Irkutsk citizens and visitors, too. Isn’t it interesting to learn “at first hand” the intimate details of the restoration of the Trubetskoys’ estate

  10. Human treadmill walking needs attention

    Directory of Open Access Journals (Sweden)

    Daniel Olivier

    2006-08-01

    Full Text Available Abstract Background The aim of the study was to assess the attentional requirements of steady state treadmill walking in human subjects using a dual task paradigm. The extent of decrement of a secondary (cognitive RT task provides a measure of the attentional resources required to maintain performance of the primary (locomotor task. Varying the level of difficulty of the reaction time (RT task is used to verify the priority of allocation of attentional resources. Methods 11 healthy adult subjects were required to walk while simultaneously performing a RT task. Participants were instructed to bite a pressure transducer placed in the mouth as quickly as possible in response to an unpredictable electrical stimulation applied on the back of the neck. Each subject was tested under five different experimental conditions: simple RT task alone and while walking, recognition RT task alone and while walking, walking alone. A foot switch system composed of a pressure sensitive sensor was placed under the heel and forefoot of each foot to determine the gait cycle duration. Results Gait cycle duration was unchanged (p > 0.05 by the addition of the RT task. Regardless of the level of difficulty of the RT task, the RTs were longer during treadmill walking than in sitting conditions (p 0.05 was found between the attentional demand of the walking task and the decrement of performance found in the RT task under varying levels of difficulty. This finding suggests that the healthy subjects prioritized the control of walking at the expense of cognitive performance. Conclusion We conclude that treadmill walking in young adults is not a purely automatic task. The methodology and outcome measures used in this study provide an assessment of the attentional resources required by walking on the treadmill at a steady state.

  11. Why Do Knuckle-Walking African Apes Knuckle-Walk?

    Science.gov (United States)

    Simpson, Scott W; Latimer, Bruce; Lovejoy, C Owen

    2018-03-01

    Among living mammals, only the African apes and some anteaters adopt knuckle-walking as their primary locomotor behavior. That Pan and Gorilla both knuckle-walk has been cited as evidence of their common ancestry and a primitive condition for a combined Homo, Pan, and Gorilla clade. Recent research on forelimb ontogeny and anatomy, in addition to recently described hominin fossils, indicate that knuckle-walking was independently acquired after divergence of the Pan and Gorilla lineages. Although the large-bodied, largely suspensory orangutan shares some aspects of the African ape bauplan, it does not regularly knuckle-walk when terrestrial. While many anatomical correlates of knuckle-walking have been identified, a functional explanation of this unusual locomotor pattern has yet to be proposed. Here, we argue that it was adopted by African apes as a means of ameliorating the consequences of repetitive impact loadings on the soft and hard tissues of the forelimb by employing isometric and/or eccentric contraction of antebrachial musculature during terrestrial locomotion. Evidence of this adaptation can be found in the differential size and fiber geometry of the forearm musculature, and differences in torso shape between the knuckle-walking and non-knuckle-walking apes (including humans). We also argue that some osteological features of the carpus and metacarpus that have been identified as adaptations to knuckle-walking are consequences of cartilage remodeling during ontogeny rather than traits limiting motion in the hand and wrist. An understanding of the functional basis of knuckle-walking provides an explanation of the locomotor parallelisms in modern Pan and Gorilla. Anat Rec, 301:496-514, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  12. Inescapable Stress Changes Walking Behavior in Flies - Learned Helplessness Revisited.

    Directory of Open Access Journals (Sweden)

    Sophie Batsching

    Full Text Available Like other animals flies develop a state of learned helplessness in response to unescapable aversive events. To show this, two flies, one 'master', one 'yoked', are each confined to a dark, small chamber and exposed to the same sequence of mild electric shocks. Both receive these shocks when the master fly stops walking for more than a second. Behavior in the two animals is differently affected by the shocks. Yoked flies are transiently impaired in place learning and take longer than master flies to exit from the chamber towards light. After the treatment they walk more slowly and take fewer and shorter walking bouts. The low activity is attributed to the fly's experience that its escape response, an innate behavior to terminate the electric shocks, does not help anymore. Earlier studies using heat pulses instead of electric shocks had shown similar effects. This parallel supports the interpretation that it is the uncontrollability that induces the state.

  13. Interventions to Increase Walking Behavior

    Science.gov (United States)

    Williams, David M.; Matthews, Charles; Rutt, Candace; Napolitano, Melissa A.; Marcus, Bess H.

    2009-01-01

    Walking is the most prevalent and preferred method of physical activity for both work and leisure purposes, thus making it a prime target for physical activity promotion interventions. We identified 14 randomized controlled trials, which tested interventions specifically targeting and assessing walking behavior. Results show that among self-selected samples intensive interventions can increase walking behavior relative to controls. Brief telephone prompts appear to be as effective as more substantial telephone counseling. Although more research is needed, individual studies support prescriptions to walk 5–7 d/wk versus 3–5 d/wk and at a moderate (versus vigorous) intensity pace, with no differences in total walking minutes when single or multiple daily walking bouts are prescribed. Mediated interventions delivering physical activity promotion materials through non-face-to-face channels may be ideal for delivering walking promotion interventions and have shown efficacy in promoting overall physical activity, especially when theory-based and individually tailored. Mass media campaigns targeting broader audiences, including those who may not intend to increase their physical activity, have been successful at increasing knowledge and awareness about physical activity, but are often too diffuse to successfully impact individual behavior change. Incorporating individually tailored programs into broader mass media campaigns may be an important next step, and the Internet could be a useful vehicle. PMID:18562974

  14. Constraining walking and custodial technicolor

    DEFF Research Database (Denmark)

    Foadi, Roshan; Frandsen, Mads Toudal; Sannino, Francesco

    2008-01-01

    We show how to constrain the physical spectrum of walking technicolor models via precision measurements and modified Weinberg sum rules. We also study models possessing a custodial symmetry for the S parameter at the effective Lagrangian level-custodial technicolor-and argue that these models...... cannot emerge from walking-type dynamics. We suggest that it is possible to have a very light spin-one axial (vector) boson. However, in the walking dynamics the associated vector boson is heavy while it is degenerate with the axial in custodial technicolor Udgivelsesdato: 19 May...

  15. Interpretive Media Study and Interpretive Social Science.

    Science.gov (United States)

    Carragee, Kevin M.

    1990-01-01

    Defines the major theoretical influences on interpretive approaches in mass communication, examines the central concepts of these perspectives, and provides a critique of these approaches. States that the adoption of interpretive approaches in mass communication has ignored varied critiques of interpretive social science. Suggests that critical…

  16. The Dead Walk

    Directory of Open Access Journals (Sweden)

    Bill Phillips

    2014-02-01

    Full Text Available Monsters have always enjoyed a significant presence in the human imagination, and religion was instrumental in replacing the physical horror they engendered with that of a moral threat. Zombies, however, are amoral – their motivation purely instinctive and arbitrary, yet they are, perhaps, the most loathed of all contemporary monsters. One explanation for this lies in the theory of the uncanny valley, proposed by robotics engineer Masahiro Mori. According to the theory, we reserve our greatest fears for those things which seem most human, yet are not – such as dead bodies. Such a reaction is most likely a survival mechanism to protect us from danger and disease – a mechanism even more essential when the dead rise up and walk. From their beginnings zombies have reflected western societies’ greatest fears – be they of revolutionary Haitians, women, or communists. In recent years the rise in the popularity of the zombie in films, books and television series reflects our fears for the planet, the economy, and of death itself

  17. Late Triassic sauropodomorph and Middle Jurassic theropod tracks from the Xichang Basin, Sichuan Province, southwestern China: First report of the ichnogenus Carmelopodus

    Directory of Open Access Journals (Sweden)

    Li-Da Xing

    2018-01-01

    Full Text Available Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus (Late Triassic and Liujianpus (Early Jurassic. The neighboring Bingtu tracksite is stratigraphically younger (Shaximiao Formation, Middle Jurassic and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation.

  18. Knuckle-walking anteater: a convergence test of adaptation for purported knuckle-walking features of African Hominidae.

    Science.gov (United States)

    Orr, Caley M

    2005-11-01

    Appeals to synapomorphic features of the wrist and hand in African apes, early hominins, and modern humans as evidence of knuckle-walking ancestry for the hominin lineage rely on accurate interpretations of those features as adaptations to knuckle-walking locomotion. Because Gorilla, Pan, and Homo share a relatively close common ancestor, the interpretation of such features is confounded somewhat by phylogeny. The study presented here examines the evolution of a similar locomotor regime in New World anteaters (order Xenarthra, family Myrmecophagidae) and uses the terrestrial giant anteater (Myrmecophaga tridactyla) as a convergence test of adaptation for purported knuckle-walking features of the Hominidae. During the stance phase of locomotion, Myrmecophaga transmits loads through flexed digits and a vertical manus, with hyperextension occurring at the metacarpophalangeal joints of the weight-bearing rays. This differs from the locomotion of smaller, arboreal anteaters of outgroup genera Tamandua and Cyclopes that employ extended wrist postures during above-branch quadrupedality. A number of features shared by Myrmecophaga and Pan and Gorilla facilitate load transmission or limit extension, thereby stabilizing the wrist and hand during knuckle-walking, and distinguish these taxa from their respective outgroups. These traits are a distally extended dorsal ridge of the distal radius, proximal expansion of the nonarticular surface of the dorsal capitate, a pronounced articular ridge on the dorsal aspects of the load-bearing metacarpal heads, and metacarpal heads that are wider dorsally than volarly. Only the proximal expansion of the nonarticular area of the dorsal capitate distinguishes knuckle-walkers from digitigrade cercopithecids, but features shared with digitigrade primates might be adaptive to the use of a vertical manus of some sort in the stance phase of terrestrial locomotion. The appearance of capitate nonarticular expansion and the dorsal ridge of the

  19. Walking around to grasp interaction

    DEFF Research Database (Denmark)

    Lykke, Marianne; Jantzen, Christian

    2013-01-01

    -alongs the research-ers acted as facilitators and partners in the engagement with the sound installa-tions. The study provided good insight into advantages and challenges with the walk-along method, for instance the importance of shared, embodied sensing of space for the understanding of the experience. The common......The paper presents experiences from a study using walk-alongs to provide insight into museum visitors’ experience with interactive features of sound art installations. The overall goal of the study was to learn about the participants’ opinions and feelings about the possibility of interaction...... with the sound installations. The aim was to gain an understanding of the role of the in-teraction, if interaction makes a difference for the understanding of the sound art. 30 walking interviews were carried out at ZKM, Karlsruhe with a total of 57 museum guests, individuals or groups. During the walk...

  20. Walking behavior in technicolored GUTs

    International Nuclear Information System (INIS)

    Doff, A.

    2009-01-01

    There exist two ways to obtain walk behavior: assuming a large number of technifermions in the fundamental representation of the technicolor (TC) gauge group, or a small number of technifermions, assuming that these fermions are in higher-dimensional representations of the TC group. We propose a scheme to obtain the walking behavior based on technicolored GUTs (TGUTs), where elementary scalars with the TC degree of freedom may remain in the theory after the GUT symmetry breaking. (orig.)

  1. Walking behavior in technicolored GUTs

    Energy Technology Data Exchange (ETDEWEB)

    Doff, A. [Universidade Tecnologica Federal do Parana-UTFPR-COMAT, Pato Branco, PR (Brazil)

    2009-03-15

    There exist two ways to obtain walk behavior: assuming a large number of technifermions in the fundamental representation of the technicolor (TC) gauge group, or a small number of technifermions, assuming that these fermions are in higher-dimensional representations of the TC group. We propose a scheme to obtain the walking behavior based on technicolored GUTs (TGUTs), where elementary scalars with the TC degree of freedom may remain in the theory after the GUT symmetry breaking. (orig.)

  2. Walking and Sustainable Urban Transportation

    OpenAIRE

    Khashayar Kashani Jou

    2012-01-01

    Walking as a type of non-motorized transportation has various social, economical and environmental privileges. Also, today different aspects of sustainable development have been emphasized and promotion of sustainable transportation modes has been considered according to this approach. Therefore, the objective of this research is exploring the circumstance of relationship between walking and sustainable urban transportation.For writing this article, the most important res...

  3. Locomotor sequence learning in visually guided walking

    DEFF Research Database (Denmark)

    Choi, Julia T; Jensen, Peter; Nielsen, Jens Bo

    2016-01-01

    Voluntary limb modifications must be integrated with basic walking patterns during visually guided walking. Here we tested whether voluntary gait modifications can become more automatic with practice. We challenged walking control by presenting visual stepping targets that instructed subjects...... visually guided walking....

  4. W' and Z' limits for Minimal Walking Technicolor

    DEFF Research Database (Denmark)

    R. Andersen, Jeppe; Hapola, Tuomas; Sannino, Francesco

    2012-01-01

    We interpret the recent data on non-observation of Z'- and W'-bosons, reported by CMS, within Minimal Walking Technicolor models and use them to constrain the couplings and spectrum of the theory. We provide the reach for both exclusion and possible observation for the LHC with 5 fb^-1 at 7 TeV...... in the centre of mass energy, and 100 fb^-1 at 13 TeV....

  5. Walking technicolor models

    International Nuclear Information System (INIS)

    King, S.F.

    1989-01-01

    Recent work on technicolor theories with small β-functions has shown that the flavour changing neutral current problem which besets any realistic extended technicolor model might be solved by Holdom's original suggestion of raising the extended technicolor scales. In this paper we apply these field theoretic ideas to the problem of constructing a realistic model of the quark and lepton mass spectrum. We discuss two closely related models: (1) An extended technicolor model based on the gauge group SO(10) ETC x SO(10) GUT ; (2) A composite/elementary extended technicolor model based on the gauge group SO(10) MC x SO(10) ETC x SU(5) GUT . Model (1) is relatively simple, and contains three families of quarks and leptons plus an SO(7) TC family of technifermions. The technicolor sector corresponds to one of the examples of walking technicolor discussed by Appelquist et al. The model is fully discussed with particular emphasis on the resulting quark and lepton mass spectrum. Charged lepton masses are adequately described, but the quark masses are degenerate in pairs with zero mixig angles. Model (2) shares the desirable low energy spectrum of Model (1) but in addition provides a mechanism for enhancing the mass of u-type quarks relative to d-type quarks, based on non-perturbative compositeness corrections. We discuss these compositeness corrections, as far as a perturbative treatment allows, and develop techniques for calculating quark masses and mixing angles. We apply these techniques to the first two families of quarks, and are encouraged to find that we can reproduce the observed features of u-d mass inversion for the first family, and Cabibbo mixing. Model (2) leads to the prediction of D 0 -anti D 0 mixing, K L → e ± μ -+ , K + → π + e - μ + , all at rates close to current experimental limits. The model also predicts three families and a top quark mass m t ≅ 50 GeV. (orig.)

  6. An Interpreter's Interpretation: Sign Language Interpreters' View of Musculoskeletal Disorders

    National Research Council Canada - National Science Library

    Johnson, William L

    2003-01-01

    ...; interpreting style, such as poor body posture, tensing muscles, signing too forcefully; job control, including the emotional and physical stress of the job, being overworked, and disliking the job...

  7. Walking Distance Estimation Using Walking Canes with Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Duc Cong Dang

    2018-01-01

    Full Text Available A walking distance estimation algorithm for cane users is proposed using an inertial sensor unit attached to various positions on the cane. A standard inertial navigation algorithm using an indirect Kalman filter was applied to update the velocity and position of the cane during movement. For quadripod canes, a standard zero-velocity measurement-updating method is proposed. For standard canes, a velocity-updating method based on an inverted pendulum model is proposed. The proposed algorithms were verified by three walking experiments with two different types of canes and different positions of the sensor module.

  8. Walking Distance Estimation Using Walking Canes with Inertial Sensors.

    Science.gov (United States)

    Dang, Duc Cong; Suh, Young Soo

    2018-01-15

    A walking distance estimation algorithm for cane users is proposed using an inertial sensor unit attached to various positions on the cane. A standard inertial navigation algorithm using an indirect Kalman filter was applied to update the velocity and position of the cane during movement. For quadripod canes, a standard zero-velocity measurement-updating method is proposed. For standard canes, a velocity-updating method based on an inverted pendulum model is proposed. The proposed algorithms were verified by three walking experiments with two different types of canes and different positions of the sensor module.

  9. Interpreting Impoliteness: Interpreters’ Voices

    Directory of Open Access Journals (Sweden)

    Tatjana Radanović Felberg

    2017-11-01

    Full Text Available Interpreters in the public sector in Norway interpret in a variety of institutional encounters, and the interpreters evaluate the majority of these encounters as polite. However, some encounters are evaluated as impolite, and they pose challenges when it comes to interpreting impoliteness. This issue raises the question of whether interpreters should take a stance on their own evaluation of impoliteness and whether they should interfere in communication. In order to find out more about how interpreters cope with this challenge, in 2014 a survey was sent to all interpreters registered in the Norwegian Register of Interpreters. The survey data were analyzed within the theoretical framework of impoliteness theory using the notion of moral order as an explanatory tool in a close reading of interpreters’ answers. The analysis shows that interpreters reported using a variety of strategies for interpreting impoliteness, including omissions and downtoning. However, the interpreters also gave examples of individual strategies for coping with impoliteness, such as interrupting and postponing interpreting. These strategies border behavioral strategies and conflict with the Norwegian ethical guidelines for interpreting. In light of the ethical guidelines and actual practice, mapping and discussing different strategies used by interpreters might heighten interpreters’ and interpreter-users’ awareness of the role impoliteness can play in institutional interpreter– mediated encounters. 

  10. Pedagogies of the Walking Dead

    Directory of Open Access Journals (Sweden)

    Michael A. Peters

    2016-04-01

    Full Text Available This paper investigates the trope of the zombie and the recent upsurge in popular culture surrounding the figure of the zombie described as the “walking dead”. We investigate this trope and figure as a means of analyzing the “pedagogy of the walking dead” with particular attention to the crisis of education in the era of neoliberal capitalism. In particular we examine the professionalization and responsibilization of teachers in the new regulative environment and ask whether there is any room left for the project of critical education.

  11. Walk Score(TM), Perceived Neighborhood Walkability, and walking in the US.

    Science.gov (United States)

    Tuckel, Peter; Milczarski, William

    2015-03-01

    To investigate both the Walk Score(TM) and a self-reported measure of neighborhood walkability ("Perceived Neighborhood Walkability") as estimators of transport and recreational walking among Americans. The study is based upon a survey of a nationally-representative sample of 1224 American adults. The survey gauged walking for both transport and recreation and included a self-reported measure of neighborhood walkability and each respondent's Walk Score(TM). Binary logistic and linear regression analyses were performed on the data. The Walk Score(TM) is associated with walking for transport, but not recreational walking nor total walking. Perceived Neighborhood Walkability is associated with transport, recreational and total walking. Perceived Neighborhood Walkability captures the experiential nature of walking more than the Walk Score(TM).

  12. Torvosaurus gurneyi n. sp., the largest terrestrial predator from Europe, and a proposed terminology of the maxilla anatomy in nonavian theropods.

    Directory of Open Access Journals (Sweden)

    Christophe Hendrickx

    Full Text Available The Lourinhã Formation (Kimmeridgian-Tithonian of Central West Portugal is well known for its diversified dinosaur fauna similar to that of the Morrison Formation of North America; both areas share dinosaur taxa including the top predator Torvosaurus, reported in Portugal. The material assigned to the Portuguese T. tanneri, consisting of a right maxilla and an incomplete caudal centrum, was briefly described in the literature and a thorough description of these bones is here given for the first time. A comparison with material referred to Torvosaurus tanneri allows us to highlight some important differences justifying the creation of a distinct Eastern species. Torvosaurus gurneyi n. sp. displays two autapomorphies among Megalosauroidea, a maxilla possessing fewer than eleven teeth and an interdental wall nearly coincidental with the lateral wall of the maxillary body. In addition, it differs from T. tanneri by a reduced number of maxillary teeth, the absence of interdental plates terminating ventrally by broad V-shaped points and falling short relative to the lateral maxillary wall, and the absence of a protuberant ridge on the anterior part of the medial shelf, posterior to the anteromedial process. T. gurneyi is the largest theropod from the Lourinhã Formation of Portugal and the largest land predator discovered in Europe hitherto. This taxon supports the mechanism of vicariance that occurred in the Iberian Meseta during the Late Jurassic when the proto-Atlantic was already well formed. A fragment of maxilla from the Lourinhã Formation referred to Torvosaurus sp. is ascribed to this new species, and several other bones, including a femur, a tibia and embryonic material all from the Kimmeridgian-Tithonian of Portugal, are tentatively assigned to T. gurneyi. A standard terminology and notation of the theropod maxilla is also proposed and a record of the Torvosaurus material from Portugal is given.

  13. Adults' Daily Walking for Travel and Leisure: Interaction Between Attitude Toward Walking and the Neighborhood Environment.

    Science.gov (United States)

    Yang, Yong; Diez-Roux, Ana V

    2017-09-01

    Studies on how the interaction of psychological and environmental characteristics influences walking are limited, and the results are inconsistent. Our aim is to examine how the attitude toward walking and neighborhood environments interacts to influence walking. Cross-sectional phone and mail survey. Participants randomly sampled from 6 study sites including Los Angeles, Chicago, Baltimore, Minneapolis, Manhattan, and Bronx Counties in New York City, and Forsyth and Davidson Counties in North Carolina. The final sample consisted of 2621 persons from 2011 to 2012. Total minutes of walking for travel or leisure, attitude toward walking, and perceptions of the neighborhood environments were self-reported. Street Smart (SS) Walk Score (a measure of walkability derived from a variety of geographic data) was obtained for each residential location. Linear regression models adjusting for age, gender, race/ethnicity, education, and income. Attitude toward walking was positively associated with walking for both purposes. Walking for travel was significantly associated with SS Walk Score, whereas walking for leisure was not. The SS Walk Score and selected perceived environment characteristics were associated with walking in people with a very positive attitude toward walking but were not associated with walking in people with a less positive attitude. Attitudes toward walking and neighborhood environments interact to affect walking behavior.

  14. On Convergent Probability of a Random Walk

    Science.gov (United States)

    Lee, Y.-F.; Ching, W.-K.

    2006-01-01

    This note introduces an interesting random walk on a straight path with cards of random numbers. The method of recurrent relations is used to obtain the convergent probability of the random walk with different initial positions.

  15. Minnesota Walk-In Access Sites

    Data.gov (United States)

    Minnesota Department of Natural Resources — The Minnesota Walk-In Access site (WIA) GIS data represents areas of private land that have been made open to the public for the purpose of walk-in (foot travel)...

  16. Quantum walks, quantum gates, and quantum computers

    International Nuclear Information System (INIS)

    Hines, Andrew P.; Stamp, P. C. E.

    2007-01-01

    The physics of quantum walks on graphs is formulated in Hamiltonian language, both for simple quantum walks and for composite walks, where extra discrete degrees of freedom live at each node of the graph. It is shown how to map between quantum walk Hamiltonians and Hamiltonians for qubit systems and quantum circuits; this is done for both single-excitation and multiexcitation encodings. Specific examples of spin chains, as well as static and dynamic systems of qubits, are mapped to quantum walks, and walks on hyperlattices and hypercubes are mapped to various gate systems. We also show how to map a quantum circuit performing the quantum Fourier transform, the key element of Shor's algorithm, to a quantum walk system doing the same. The results herein are an essential preliminary to a Hamiltonian formulation of quantum walks in which coupling to a dynamic quantum environment is included

  17. Taking Light For a Walk

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 11. Taking Light For a Walk. Anita R Warrier C Vijayan. General Article Volume 18 Issue 11 November 2013 pp 1015-1031. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/018/11/1015-1031 ...

  18. Random walk over a hypersphere

    Directory of Open Access Journals (Sweden)

    J. M. C. Joshi

    1985-01-01

    A generalization of Hammersley's result has also been developed. The main purpose of the paper is to show that although the use of characteristic functions, using the method of Bochner, is available in problems of random walk yet distributional S. M. Joshi transform can be used as a natural tool has been proved for the first time in the paper.

  19. "A Walk with Robert Frost."

    Science.gov (United States)

    Gustafson, John A.

    1984-01-01

    Describes a field exercise using nature poetry to enlarge and give emotional content to ecological ideas. The trip involves walking in silence (except during poetry readings) through a natural area where objects or situations illustrated in the poetry are found. Recommended readings on specific details and ideas are provided. (BC)

  20. Nine walks (photo series / web page)

    OpenAIRE

    Robinson, Andrew

    2015-01-01

    'Nine Walks' is a body of work resulting from my engagement with the Media Arts Research Walking Group at Sheffield Hallam University who are exploring the role of walking in as a social, developmental and production space for the creative arts. / My participation in the walking group is an extension of my investigation of the journey as a creative, conceptual and contemplative space for photography which in turn reflects an interest in the role of the accident, instinct and intuition and the...

  1. Treadmill walking with body weight support

    OpenAIRE

    Aaslund, Mona Kristin

    2012-01-01

    Background: Rehabilitating walking in patients post-stroke with safe, task-specific, intensive training of sufficient duration, can be challenging. Body weight supported treadmill training (BWSTT) has been proposed as an effective method to meet these challenges and may therefore have benefits over training overground walking. However, walking characteristics should not be aggravated during BWSTT or require a long familiarisation time compared to overground walking. Objectives: To investi...

  2. It's how you get there: Walking down a virtual alley activates premotor and parietal areas

    Directory of Open Access Journals (Sweden)

    Johanna eWagner

    2014-02-01

    Full Text Available Voluntary drive is crucial for motor learning, therefore we are interested in the role that motor planning plays in gait movements. In this study we examined the impact of an interactive Virtual Environment (VE feedback task on the EEG patterns during robot assisted walking. We compared walking in the VE modality to two control conditions: walking with a visual attention paradigm, in which visual stimuli were unrelated to the motor task; and walking with mirror feedback, in which participants observed their own movements. Eleven healthy participants were considered. Application of independent component analysis to the EEG revealed three independent component clusters in premotor and parietal areas showing increased activity during walking with the adaptive VE training paradigm compared to the control conditions. During the interactive VE walking task spectral power in frequency ranges 8-12Hz, 15-20Hz and 23-40Hz was significantly (p ≤ 0.05 decreased. This power decrease is interpreted as a correlate of an active cortical area. Furthermore activity in the premotor cortex revealed gait cycle related modulations significantly different (p ≤ 0.05 from baseline in the frequency range 23-40Hz during walking. These modulations were significantly (p ≤ 0.05 reduced depending on gait cycle phases in the interactive VE walking task compared to the control conditions.We demonstrate that premotor and parietal areas show increased activity during walking with the adaptive VE training paradigm, when compared to walking with mirror- and movement unrelated feedback. Previous research has related a premotor-parietal network to motor planning and motor intention. We argue that movement related interactive feedback enhances motor planning and motor intention. We hypothesize that this might improve gait recovery during rehabilitation.

  3. Walking pattern classification and walking distance estimation algorithms using gait phase information.

    Science.gov (United States)

    Wang, Jeen-Shing; Lin, Che-Wei; Yang, Ya-Ting C; Ho, Yu-Jen

    2012-10-01

    This paper presents a walking pattern classification and a walking distance estimation algorithm using gait phase information. A gait phase information retrieval algorithm was developed to analyze the duration of the phases in a gait cycle (i.e., stance, push-off, swing, and heel-strike phases). Based on the gait phase information, a decision tree based on the relations between gait phases was constructed for classifying three different walking patterns (level walking, walking upstairs, and walking downstairs). Gait phase information was also used for developing a walking distance estimation algorithm. The walking distance estimation algorithm consists of the processes of step count and step length estimation. The proposed walking pattern classification and walking distance estimation algorithm have been validated by a series of experiments. The accuracy of the proposed walking pattern classification was 98.87%, 95.45%, and 95.00% for level walking, walking upstairs, and walking downstairs, respectively. The accuracy of the proposed walking distance estimation algorithm was 96.42% over a walking distance.

  4. Interpreting. PEPNet Tipsheet

    Science.gov (United States)

    Darroch, Kathleen

    2010-01-01

    An interpreter's role is to facilitate communication and convey all auditory and signed information so that both hearing and deaf individuals may fully interact. The common types of services provided by interpreters are: (1) American Sign Language (ASL) Interpretation--a visual-gestural language with its own linguistic features; (2) Sign Language…

  5. Engineering Definitional Interpreters

    DEFF Research Database (Denmark)

    Midtgaard, Jan; Ramsay, Norman; Larsen, Bradford

    2013-01-01

    A definitional interpreter should be clear and easy to write, but it may run 4--10 times slower than a well-crafted bytecode interpreter. In a case study focused on implementation choices, we explore ways of making definitional interpreters faster without expending much programming effort. We...

  6. Journalists as Interpretive Communities.

    Science.gov (United States)

    Zelizer, Barbie

    1993-01-01

    Proposes viewing journalists as members of an interpretive community (not a profession) united by its shared discourse and collective interpretations of key public events. Applies the frame of the interpretive community to journalistic discourse about two events central for American journalists--Watergate and McCarthyism. (SR)

  7. Development of independent walking in toddlers

    NARCIS (Netherlands)

    Ivanenko, Yuri P; Dominici, Nadia; Lacquaniti, Francesco

    Surprisingly, despite millions of years of bipedal walking evolution, the gravity-related pendulum mechanism of walking does not seem to be implemented at the onset of independent walking, requiring each toddler to develop it. We discuss the precursor of the mature locomotor pattern in infants as an

  8. Random walks in a random environment

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. Random walks as well as diffusions in random media are considered. Methods are developed that allow one to establish large deviation results for both the 'quenched' and the 'averaged' case. Keywords. Large deviations; random walks in a random environment. 1. Introduction. A random walk on Zd is a stochastic ...

  9. Walking Beliefs in Women With Fibromyalgia: Clinical Profile and Impact on Walking Behavior.

    Science.gov (United States)

    Peñacoba, Cecilia; Pastor, María-Ángeles; López-Roig, Sofía; Velasco, Lilian; Lledo, Ana

    2017-10-01

    Although exercise is essential for the treatment of fibromyalgia, adherence is low. Walking, as a form of physical exercise, has significant advantages. The aim of this article is to describe, in 920 women with fibromyalgia, the prevalence of certain walking beliefs and analyze their effects both on the walking behavior itself and on the associated symptoms when patients walk according to a clinically recommended way. The results highlight the high prevalence of beliefs related to pain and fatigue as walking-inhibitors. In the whole sample, beliefs are associated with an increased perception that comorbidity prevents walking, and with higher levels of pain and fatigue. In patients who walk regularly, beliefs are only associated with the perception that comorbidity prevents them from walking. It is necessary to promote walking according to the established way (including breaks to prevent fatigue) and to implement interventions on the most prevalent beliefs that inhibit walking.

  10. Estimating mood variation from MPF of EMG during walking.

    Science.gov (United States)

    Kinase, Yuta; Venture, Gentiane

    2013-01-01

    The information on the mood included in behavior is classified into nonverbal information, and is included in behavior without necessarily being based on the intention of an agent. Consequently, it is considered that we can estimate the mood from the measurement of the behavior. In this work, we estimate the mood from the surface electromyogram (EMG) information of the muscles of the upper limb during walking. Identification of emotion and mood using EMG information has been done with a variety of methods until now. In addition, it is known that human walking includes information that is specific to the individual and be affected by mood. Therefore, it is thought that the EMG analysis of walking is effective in the identification of human mood. In this work, we made a subject walk in the various mood states and answer psychological tests that measure the mood. We use two types of tasks (music listening and numerical calculation) for evoking different moods. Statistical features of EMG signals are calculated using Fast Fourier Transform (FFT) and Principal Component Analysis (PCA). These statistical features are related with psychological test scores, using regression analysis. In this paper, we have shown the statistical significance of the linear model to predict the variation of mood based on the information on the variation in MPF of EMG data of the muscles of the upper limb during walking with different moods. This shows the validity of such a mapping. However, since the interpretability of the model is still low, it cannot be said that the model is able to accurately represent the mood variation. Creating a model with high accuracy is a key issue in the future.

  11. Analyzing Walking Route Choice through Built Environments using Random Forests and Discrete Choice Techniques.

    Science.gov (United States)

    Tribby, Calvin P; Miller, Harvey J; Brown, Barbara B; Werner, Carol M; Smith, Ken R

    2017-11-01

    Walking is a form of active transportation with numerous benefits, including better health outcomes, lower environmental impacts and stronger communities. Understanding built environmental associations with walking behavior is a key step towards identifying design features that support walking. Human mobility data available through GPS receivers and cell phones, combined with high resolution walkability data, provide a rich source of georeferenced data for analyzing environmental associations with walking behavior. However, traditional techniques such as route choice models have difficulty with highly dimensioned data. This paper develops a novel combination of a data-driven technique with route choice modeling for leveraging walkability audits. Using data from a study in Salt Lake City, Utah, USA, we apply the data-driven technique of random forests to select variables for use in walking route choice models. We estimate data-driven route choice models and theory-driven models based on predefined walkability dimensions. Results indicate that the random forest technique selects variables that dramatically improve goodness of fit of walking route choice models relative to models based on predefined walkability dimensions. We compare the theory-driven and data-driven walking route choice models based on interpretability and policy relevance.

  12. Equivalence of Szegedy's and coined quantum walks

    Science.gov (United States)

    Wong, Thomas G.

    2017-09-01

    Szegedy's quantum walk is a quantization of a classical random walk or Markov chain, where the walk occurs on the edges of the bipartite double cover of the original graph. To search, one can simply quantize a Markov chain with absorbing vertices. Recently, Santos proposed two alternative search algorithms that instead utilize the sign-flip oracle in Grover's algorithm rather than absorbing vertices. In this paper, we show that these two algorithms are exactly equivalent to two algorithms involving coined quantum walks, which are walks on the vertices of the original graph with an internal degree of freedom. The first scheme is equivalent to a coined quantum walk with one walk step per query of Grover's oracle, and the second is equivalent to a coined quantum walk with two walk steps per query of Grover's oracle. These equivalences lie outside the previously known equivalence of Szegedy's quantum walk with absorbing vertices and the coined quantum walk with the negative identity operator as the coin for marked vertices, whose precise relationships we also investigate.

  13. Nordic walking and chronic low back pain

    DEFF Research Database (Denmark)

    Morsø, Lars; Hartvigsen, Jan; Puggaard, Lis

    2006-01-01

    activity provide similar benefits. Nordic Walking is a popular and fast growing type of exercise in Northern Europe. Initial studies have demonstrated that persons performing Nordic Walking are able to exercise longer and harder compared to normal walking thereby increasing their cardiovascular metabolism....... Until now no studies have been performed to investigate whether Nordic Walking has beneficial effects in relation to low back pain. The primary aim of this study is to investigate whether supervised Nordic Walking can reduce pain and improve function in a population of chronic low back pain patients...... when compared to unsupervised Nordic Walking and advice to stay active. In addition we investigate whether there is an increase in the cardiovascular metabolism in persons performing supervised Nordic Walking compared to persons who are advised to stay active. Finally, we investigate whether...

  14. Groups, graphs and random walks

    CERN Document Server

    Salvatori, Maura; Sava-Huss, Ecaterina

    2017-01-01

    An accessible and panoramic account of the theory of random walks on groups and graphs, stressing the strong connections of the theory with other branches of mathematics, including geometric and combinatorial group theory, potential analysis, and theoretical computer science. This volume brings together original surveys and research-expository papers from renowned and leading experts, many of whom spoke at the workshop 'Groups, Graphs and Random Walks' celebrating the sixtieth birthday of Wolfgang Woess in Cortona, Italy. Topics include: growth and amenability of groups; Schrödinger operators and symbolic dynamics; ergodic theorems; Thompson's group F; Poisson boundaries; probability theory on buildings and groups of Lie type; structure trees for edge cuts in networks; and mathematical crystallography. In what is currently a fast-growing area of mathematics, this book provides an up-to-date and valuable reference for both researchers and graduate students, from which future research activities will undoubted...

  15. Chemical Continuous Time Random Walks

    Science.gov (United States)

    Aquino, Tomás; Dentz, Marco

    2017-12-01

    Kinetic Monte Carlo methods such as the Gillespie algorithm model chemical reactions as random walks in particle number space. The interreaction times are exponentially distributed under the assumption that the system is well mixed. We introduce an arbitrary interreaction time distribution, which may account for the impact of incomplete mixing on chemical reactions, and in general stochastic reaction delay, which may represent the impact of extrinsic noise. This process defines an inhomogeneous continuous time random walk in particle number space, from which we derive a generalized chemical master equation. This leads naturally to a generalization of the Gillespie algorithm. Based on this formalism, we determine the modified chemical rate laws for different interreaction time distributions. This framework traces Michaelis-Menten-type kinetics back to finite-mean delay times, and predicts time-nonlocal macroscopic reaction kinetics as a consequence of broadly distributed delays. Non-Markovian kinetics exhibit weak ergodicity breaking and show key features of reactions under local nonequilibrium.

  16. City Walks and Tactile Experience

    Directory of Open Access Journals (Sweden)

    Mădălina Diaconu

    2011-01-01

    Full Text Available This paper is an attempt to develop categories of the pedestrian’s tactile and kinaesthetic experience of the city. The beginning emphasizes the haptic qualities of surfaces and textures, which can be “palpated” visually or experienced by walking. Also the lived city is three-dimensional; its corporeal depth is discussed here in relation to the invisible sewers, protuberant profiles, and the formal diversity of roofscapes. A central role is ascribed in the present analysis to the formal similarities between the representation of the city by walking through it and the representation of the tactile form of objects. Additional aspects of the “tactile” experience of the city in a broad sense concern the feeling of their rhythms and the exposure to weather conditions. Finally, several aspects of contingency converge in the visible age of architectural works, which record traces of individual and collective histories.

  17. Stable walking with asymmetric legs

    International Nuclear Information System (INIS)

    Merker, Andreas; Rummel, Juergen; Seyfarth, Andre

    2011-01-01

    Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

  18. Object Study Walk. BLOK P

    Directory of Open Access Journals (Sweden)

    Tone Huse

    2017-03-01

    Full Text Available I would like to take you for a walk, around the housing complex Blok P in the centre of Nuuk, Greenland. I encourage you to move and listen, to smell and touch. In the presence of your evoked senses, linger for a moment; turn your face towards the past. Let us explore urban nostalgia, not as an either/or reactionary, speculative, radical, or future-oriented but as the organizing narrative of our shared journey.

  19. Spin lattices of walking droplets

    Science.gov (United States)

    Saenz, Pedro; Pucci, Giuseppe; Goujon, Alexis; Dunkel, Jorn; Bush, John

    2017-11-01

    We present the results of an experimental investigation of the spontaneous emergence of collective behavior in spin lattice of droplets walking on a vibrating fluid bath. The bottom topography consists of relatively deep circular wells that encourage the walking droplets to follow circular trajectories centered at the lattice sites, in one direction or the other. Wave-mediated interactions between neighboring drops are enabled through a thin fluid layer between the wells. The sense of rotation of the walking droplets may thus become globally coupled. When the coupling is sufficiently strong, interactions with neighboring droplets may result in switches in spin that lead to preferred global arrangements, including correlated (all drops rotating in the same direction) or anti-correlated (neighboring drops rotating in opposite directions) states. Analogies with ferromagnetism and anti-ferromagnetism are drawn. Different spatial arrangements are presented in 1D and 2D lattices to illustrate the effects of topological frustration. This work was supported by the US National Science Foundation through Grants CMMI-1333242 and DMS-1614043.

  20. Genre and Interpretation

    DEFF Research Database (Denmark)

    Auken, Sune

    2015-01-01

    Despite the immensity of genre studies as well as studies in interpretation, our understanding of the relationship between genre and interpretation is sketchy at best. The article attempts to unravel some of intricacies of that relationship through an analysis of the generic interpretation carried...... out by us all in everyday life, and the role of generic interpretation in scholarly work. The article argues that the role played by genre in interpretation has as much to do with the individual characteristics of an utterance as with its relationship to other utterances. An interest in the generic...... traits of an utterance will lead to a characterization of its individual, as well as its general characteristics. The article proceeds to describe three central concepts within genre studies that are applicable to generic interpretation: “horizon of expectation,” “world,” and the triad “theme...

  1. On court interpreters' visibility

    DEFF Research Database (Denmark)

    Dubslaff, Friedel; Martinsen, Bodil

    in by the participants almost immediately after the interrogations and supplemented by interviews. The main objective of the project is to explore the interpreters' own perception of the quality of the service they render as well as the professional users´ and the other language users' perception of the quality...... of the service they receive. Ultimately, the findings will be used for training purposes. Future - and, for that matter, already practising - interpreters as well as the professional users of interpreters ought to take the reality of the interpreters' work in practice into account when assessing the quality......, such as the interpreter's engagement in explicit co-construction of meaning. In addition, we shall include social factors which must be assumed to have a bearing on the interpreter's behaviour. Here we can, at least to some extent, draw upon the questionnaires and interviews mentioned above. Finally, we shall discuss...

  2. Predicting outcomes from 6-minute walk distance in chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Spruit, Martijn A; Polkey, Michael I; Celli, Bartolome

    2012-01-01

    Exercise tolerance is an important clinical aspect of chronic obstructive pulmonary disease that can be easily and reliably measured with the 6-minute walking test (6MWT). To improve the utility of the 6MWT for patient and health care system management, the interpretation of the functional status...

  3. Generalized Continuous-Time Random Walks (CTRW), Subordination by Hitting Times and Fractional Dynamics

    OpenAIRE

    Kolokoltsov, Vassili N.

    2007-01-01

    Functional limit theorem for continuous-time random walks (CTRW) are found in general case of dependent waiting times and jump sizes that are also position dependent. The limiting anomalous diffusion is described in terms of fractional dynamics. Probabilistic interpretation of generalized fractional evolution is given in terms of the random time change (subordination) by means of hitting times processes.

  4. Interpreting land records

    CERN Document Server

    Wilson, Donald A

    2014-01-01

    Base retracement on solid research and historically accurate interpretation Interpreting Land Records is the industry's most complete guide to researching and understanding the historical records germane to land surveying. Coverage includes boundary retracement and the primary considerations during new boundary establishment, as well as an introduction to historical records and guidance on effective research and interpretation. This new edition includes a new chapter titled "Researching Land Records," and advice on overcoming common research problems and insight into alternative resources wh

  5. Patient satisfaction of using the ActiGait® drop foot stimulator system and effect of treatment on walking

    DEFF Research Database (Denmark)

    Larsen, Birgit Tine; Severinsen, Kåre; Grey, Kurt

    2014-01-01

    in a clinical setting at Aalborg University Hospital. Using The Canadian Occupational Performance Measurement and a ten meter walk test as well as standard neurophysiological measurements we demonstrate an increase in self- assessed walking performance and patient satisfaction and an apparent increase......In this case-control study of ten chronic stroke patients with drop foot we report preliminary data on patient satisfaction, self- assessed changes in walking performance, effect on walking speed as well as adverse effects after surgical implantation of the ActiGait® drop foot stimulator...... performed three, six and twelve months after implantation demonstrating an increasing degree of patient satisfaction over time. Implementation of ActiGait® in a daily clinical setting seems safe with high patient satisfaction whereas, interpretation of the effect on walking speed must be performed...

  6. Patient Satisfaction of Using the ActiGait® Drop Foot Stimulator System and Effect of Treatment on Walking

    DEFF Research Database (Denmark)

    Severinsen, Kåre Eg; Grey, Kurt; Juhl, Anne

    2014-01-01

    In this case-control study of ten chronic stroke patients with drop foot we report preliminary data on patient satisfaction, self- assessed changes in walking performance, effect on walking speed as well as adverse effects after surgical implantation of the ActiGait® drop foot stimulator...... in a clinical setting at Aalborg University Hospital. Using The Canadian Occupational Performance Measurement and a ten meter walk test as well as standard neurophysiological measurements we demonstrate an increase in self- assessed walking performance and patient satisfaction and an apparent increase...... performed three, six and twelve months after implantation demonstrating an increasing degree of patient satisfaction over time. Implementation of ActiGait® in a daily clinical setting seems safe with high patient satisfaction whereas, interpretation of the effect on walking speed must be performed...

  7. Random walks and diffusion on networks

    Science.gov (United States)

    Masuda, Naoki; Porter, Mason A.; Lambiotte, Renaud

    2017-11-01

    Random walks are ubiquitous in the sciences, and they are interesting from both theoretical and practical perspectives. They are one of the most fundamental types of stochastic processes; can be used to model numerous phenomena, including diffusion, interactions, and opinions among humans and animals; and can be used to extract information about important entities or dense groups of entities in a network. Random walks have been studied for many decades on both regular lattices and (especially in the last couple of decades) on networks with a variety of structures. In the present article, we survey the theory and applications of random walks on networks, restricting ourselves to simple cases of single and non-adaptive random walkers. We distinguish three main types of random walks: discrete-time random walks, node-centric continuous-time random walks, and edge-centric continuous-time random walks. We first briefly survey random walks on a line, and then we consider random walks on various types of networks. We extensively discuss applications of random walks, including ranking of nodes (e.g., PageRank), community detection, respondent-driven sampling, and opinion models such as voter models.

  8. Positive messaging promotes walking in older adults.

    Science.gov (United States)

    Notthoff, Nanna; Carstensen, Laura L

    2014-06-01

    Walking is among the most cost-effective and accessible means of exercise. Mounting evidence suggests that walking may help to maintain physical and cognitive independence in old age by preventing a variety of health problems. However, older Americans fall far short of meeting the daily recommendations for walking. In 2 studies, we examined whether considering older adults' preferential attention to positive information may effectively enhance interventions aimed at promoting walking. In Study 1, we compared the effectiveness of positive, negative, and neutral messages to encourage walking (as measured with pedometers). Older adults who were informed about the benefits of walking walked more than those who were informed about the negative consequences of failing to walk, whereas younger adults were unaffected by framing valence. In Study 2, we examined within-person change in walking in older adults in response to positively- or negatively-framed messages over a 28-day period. Once again, positively-framed messages more effectively promoted walking than negatively-framed messages, and the effect was sustained across the intervention period. Together, these studies suggest that consideration of age-related changes in preferences for positive and negative information may inform the design of effective interventions to promote healthy lifestyles. Future research is needed to examine the mechanisms underlying the greater effectiveness of positively- as opposed to negatively-framed messages and the generalizability of findings to other intervention targets and other subpopulations of older adults. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  9. Does walking in nature restore directed attention?

    Directory of Open Access Journals (Sweden)

    2015-09-01

    Full Text Available Aims: Mental fatigue is commonly understood and experienced as mental exhaustion, irritability and foggy thinking. Research indicates mental fatigue is indicative of depleted directed attention resources. Thus, restoration of directed attention is thought to alleviate mental fatigue. This research sought to determine if walking in nature compared to walking on a treadmill provided enhanced performance on tasks of directed attention. Method: Twenty-two participants completed a 30-min walk on a treadmill and a walk in the local Botanic Garden on separate days. Two directed attention tasks (Rapid Visual Information Processing (RVIP and Necker Cube reversal task were conducted both before and after each walk as well as a Perceived Arousal Scale and a Positive and Negative Affect Schedule. Results: Total hits and sensitivity to a target on a RVIP task improved significantly in both locations F(1, 20 = 11.892, p = .003, F(1, 20 = 12.364, p = .002 respectively. However, there was no significant difference between the nature walk and the treadmill walk. Significant order effects were found for sensitivity to targets pre/post walks, F(1, 19 = 10.309, p = .005 and F(1, 19 = 8.578, p = .009 respectively. Necker cube baseline scores indicated a significant reduction in reversals after 30 minutes of walking in both locations. Arousal was higher overall in the nature walk compared to the treadmill walk, F(1, 20 = 11.626, p = .003. Conclusions: No evidence was obtained to suggest that walking in nature leads to improved directed attention compared to walking on a treadmill. Results indicate that improvements were due to significant learning affects. The significantly higher overall score on the arousal scale in the natural environment suggests that participants were more alert in this environment.

  10. A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the “middle” Cretaceous of Morocco

    Directory of Open Access Journals (Sweden)

    Serjoscha W. Evers

    2015-10-01

    Full Text Available Sigilmassasaurus brevicollis is an enigmatic theropod dinosaur from the early Late Cretaceous (Cenomanian of Morocco, originally based on a few isolated cervical vertebrae. Ever since its original description, both its taxonomic validity and systematic affinities were contentious. Originally considered to represent its own family, Sigilmassasauridae, the genus has variously been suggested to represent a carcharodontosaurid, an ornithischian, and, more recently, a spinosaurid. Here we describe new remains referrable to this taxon and re-evaluate its taxonomic status and systematic affinities. Based on the new remains, a re-evaluation of the original materials, and comparisons with other spinosaurids, the holotype of Sigilmassasaurus brevicollis is identified as an anterior dorsal, rather than a cervical vertebra, and differences between elements referred to this taxon can be explained by different positions of the elements in question within the vertebral column. Many characters used previously to diagnose the genus and species are found to be more widespread among basal tetanurans, and specifically spinosaurids. However, the taxon shows several autapomorphies that support its validity, including the presence of a strongly rugose, ventrally offset triangular platform that is confluent with a ventral keel anteriorly in the mid-cervical vertebral centra and a strongly reduced lateral neural arch lamination, with no or an incomplete distinction between anterior and posterior centrodiapophyseal laminae in the posterior cervical and anterior dorsal vertebrae. We argue furthermore that Spinosaurus maroccanus, also described on the basis of isolated cervical vertebrae from the same stratigraphic unit and in the same paper as Sigilmassasaurus brevicollis, is a subjective synonym of the latter. Both a detailed comparison of this taxon with other theropods and a formal phylogenetic analysis support spinosaurid affintities for Sigilmassasaurus. However, we

  11. Walk-Startup of a Two-Legged Walking Mechanism

    Science.gov (United States)

    Babković, Kalman; Nagy, László; Krklješ, Damir; Borovac, Branislav

    There is a growing interest towards humanoid robots. One of their most important characteristic is the two-legged motion - walk. Starting and stopping of humanoid robots introduce substantial delays. In this paper, the goal is to explore the possibility of using a short unbalanced state of the biped robot to quickly gain speed and achieve the steady state velocity during a period shorter than half of the single support phase. The proposed method is verified by simulation. Maintainig a steady state, balanced gait is not considered in this paper.

  12. Linguistics in Text Interpretation

    DEFF Research Database (Denmark)

    Togeby, Ole

    2011-01-01

    A model for how text interpretation proceeds from what is pronounced, through what is said to what is comunicated, and definition of the concepts 'presupposition' and 'implicature'.......A model for how text interpretation proceeds from what is pronounced, through what is said to what is comunicated, and definition of the concepts 'presupposition' and 'implicature'....

  13. Acquiring specific interpreting competence

    Directory of Open Access Journals (Sweden)

    Jana Zidar Forte

    2012-12-01

    Full Text Available In postgraduate interpreter training, the main objective of the course is to help trainees develop various competences, from linguistic, textual and cultural competence, to professional and specific interpreting competence. For simultaneous interpreting (SI, the main focus is on mastering the SI technique and strategies as well as on developing and strengthening communicative skills, which is discussed and illustrated with examples in the present paper. First, a brief overview is given of all the necessary competences of a professional interpreter with greater emphasis on specific interpreting competence for SI. In the second part of the paper, various approaches are described in terms of acquiring specific skills and strategies, specifically through a range of exercises. Besides interpreting entire speeches, practical courses should also consist of targeted exercises, which help trainees develop suitable coping strategies and mechanisms (later on almost automatisms, while at the same time "force" them to reflect on their individual learning process and interpreting performance. This provides a solid base on which trained interpreters can progress and develop their skills also after joining the professional sphere.

  14. Life Cycle Interpretation

    DEFF Research Database (Denmark)

    Bonou, Alexandra; Olsen, Stig Irving

    2017-01-01

    an interpretation. The process of interpretation starts with identification of potentially significant issues in the previous stages of goal and scope definition, inventory analysis and impact assessment, and examples of potential significant issues are given for each phase. The significance is then determined...

  15. Nordic walking versus walking without poles for rehabilitation with cardiovascular disease: Randomized controlled trial.

    Science.gov (United States)

    Girold, Sébastien; Rousseau, Jérome; Le Gal, Magalie; Coudeyre, Emmanuel; Le Henaff, Jacqueline

    2017-07-01

    With Nordic walking, or walking with poles, one can travel a greater distance and at a higher rate than with walking without poles, but whether the activity is beneficial for patients with cardiovascular disease is unknown. This randomized controlled trial was undertaken to determine whether Nordic walking was more effective than walking without poles on walk distance to support rehabilitation training for patients with acute coronary syndrome (ACS) and peripheral arterial occlusive disease (PAOD). Patients were recruited in a private specialized rehabilitation centre for cardiovascular diseases. The entire protocol, including patient recruitment, took place over 2 months, from September to October 2013. We divided patients into 2 groups: Nordic Walking Group (NWG, n=21) and Walking Group without poles (WG, n=21). All patients followed the same program over 4 weeks, except for the walk performed with or without poles. The main outcome was walk distance on the 6-min walk test. Secondary outcomes were maximum heart rate during exercise and walk distance and power output on a treadmill stress test. We included 42 patients (35 men; mean age 57.2±11 years and BMI 26.5±4.5kg/m 2 ). At the end of the training period, both groups showed improved walk distance on the 6-min walk test and treatment stress test as well as power on the treadmill stress test (Ptraining period, Nordic walking training appeared more efficient than training without poles for increasing walk distance on the 6-min walk test for patients with ACS and PAOD. Copyright © 2017. Published by Elsevier Masson SAS.

  16. Differences in walking pattern during 6-min walk test between patients with COPD and healthy subjects.

    Science.gov (United States)

    Annegarn, Janneke; Spruit, Martijn A; Savelberg, Hans H C M; Willems, Paul J B; van de Bool, Coby; Schols, Annemie M W J; Wouters, Emiel F M; Meijer, Kenneth

    2012-01-01

    To date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT) have not been performed in patients with chronic obstructive pulmonary disease (COPD). Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects. 79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability) and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD) using multiple ordinary least squares (OLS) regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%). COPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD.

  17. Quantum walks driven by many coins

    International Nuclear Information System (INIS)

    Brun, Todd A.; Ambainis, Andris; Carteret, Hilary A.

    2003-01-01

    Quantum random walks have been much studied recently, largely due to their highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum random walk on the line: the use of multiple quantum 'coins' (or more generally, coins of higher dimension) in order to diminish the effects of interference between paths. We find solutions to this system in terms of the single-coin random walk, and compare the asymptotic limit of these solutions to numerical simulations. We find exact analytical expressions for the time dependence of the first two moments, and show that in the long-time limit the ''quantum-mechanical'' behavior of the one-coin walk persists, even if each coin is flipped only twice. We further show that this is generic for a very broad class of possible walks, and that this behavior disappears only in the limit of a new coin for every step of the walk

  18. Coined quantum walks on weighted graphs

    Science.gov (United States)

    Wong, Thomas G.

    2017-11-01

    We define a discrete-time, coined quantum walk on weighted graphs that is inspired by Szegedy’s quantum walk. Using this, we prove that many lackadaisical quantum walks, where each vertex has l integer self-loops, can be generalized to a quantum walk where each vertex has a single self-loop of real-valued weight l. We apply this real-valued lackadaisical quantum walk to two problems. First, we analyze it on the line or one-dimensional lattice, showing that it is exactly equivalent to a continuous deformation of the three-state Grover walk with faster ballistic dispersion. Second, we generalize Grover’s algorithm, or search on the complete graph, to have a weighted self-loop at each vertex, yielding an improved success probability when l < 3 + 2\\sqrt{2} ≈ 5.828 .

  19. Can psychology walk the walk of open science?

    Science.gov (United States)

    Hesse, Bradford W

    2018-01-01

    An "open science movement" is gaining traction across many disciplines within the research enterprise but is also precipitating consternation among those who worry that too much disruption may be hampering professional productivity. Despite this disruption, proponents of open data collaboration have argued that some of the biggest problems of the 21st century need to be solved with the help of many people and that data sharing will be the necessary engine to make that happen. In the United States, a national strategic plan for data sharing encouraged the federally funded scientific agencies to (a) publish open data for community use in discoverable, machine-readable, and useful ways; (b) work with public and civil society organizations to set priorities for data to be shared; (c) support innovation and feedback on open data solutions; and (d) continue efforts to release and enhance high-priority data sets funded by taxpayer dollars. One of the more visible open data projects in the psychological sciences is the presidentially announced "Brain Research Through Advancing Innovative Neurotechnologies" (BRAIN) initiative. Lessons learned from initiatives such as these are instructive both from the perspective of open science within psychology and from the perspective of understanding the psychology of open science. Recommendations for creating better pathways to "walk the walk" in open science include (a) nurturing innovation and agile learning, (b) thinking outside the paradigm, (c) creating simplicity from complexity, and (d) participating in continuous learning evidence platforms. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  20. A discrete random walk on the hypercube

    Science.gov (United States)

    Zhang, Jingyuan; Xiang, Yonghong; Sun, Weigang

    2018-03-01

    In this paper, we study the scaling for mean first-passage time (MFPT) of random walks on the hypercube and obtain a closed-form formula for the MFPT over all node pairs. We also determine the exponent of scaling efficiency characterizing the random walks and compare it with those of the existing networks. Finally we study the random walks on the hypercube with a located trap and provide a solution of the Kirchhoff index of the hypercube.

  1. Quantum Walks for Computer Scientists

    CERN Document Server

    Venegas-Andraca, Salvador

    2008-01-01

    Quantum computation, one of the latest joint ventures between physics and the theory of computation, is a scientific field whose main goals include the development of hardware and algorithms based on the quantum mechanical properties of those physical systems used to implement such algorithms. Solving difficult tasks (for example, the Satisfiability Problem and other NP-complete problems) requires the development of sophisticated algorithms, many of which employ stochastic processes as their mathematical basis. Discrete random walks are a popular choice among those stochastic processes. Inspir

  2. Energy expenditure of nordic walking and conventional walking assessed by accelerometer

    Directory of Open Access Journals (Sweden)

    Mynarski Władysław

    2014-12-01

    Full Text Available Study aim: the objective was to assess and compare the energy expenditure (EE and exercise heart rate (EHR during Nordic Walking (NW, and conventional walking (W in physical education and tourism/recreation university students.

  3. The Relationship Between Arm Movement and Walking Stability in Bipedal Walking

    National Research Council Canada - National Science Library

    Shibukawa, Miki

    2001-01-01

    ... analysis of walking for use in rehabilitation programs. The analysis of walking movement has generally focused on the legs rather than the arms, probably due to a perception that the arms do not play an essential role in this movement...

  4. Effect of Body Composition on Walking Economy

    Directory of Open Access Journals (Sweden)

    Maciejczyk Marcin

    2016-12-01

    Full Text Available Purpose. The aim of the study was to evaluate walking economy and physiological responses at two walking speeds in males with similar absolute body mass but different body composition. Methods. The study involved 22 young men with similar absolute body mass, BMI, aerobic performance, calf and thigh circumference. The participants differed in body composition: body fat (HBF group and lean body mass (HLBM group. In the graded test, maximal oxygen uptake (VO2max and maximal heart rate were measured. Walking economy was evaluated during two walks performed at two different speeds (4.8 and 6.0 km ‧ h-1. Results. The VO2max was similar in both groups, as were the physiological responses during slow walking. The absolute oxygen uptake or oxygen uptake relative to body mass did not significantly differentiate the studied groups. The only indicator significantly differentiating the two groups was oxygen uptake relative to LBM. Conclusions. Body composition does not significantly affect walking economy at low speed, while during brisk walking, the economy is better in the HLBM vs. HBF group, provided that walking economy is presented as oxygen uptake relative to LBM. For this reason, we recommend this manner of oxygen uptake normalization in the evaluation of walking economy.

  5. Thermodynamics and entanglements of walks under stress

    International Nuclear Information System (INIS)

    Janse van Rensburg, E J; Orlandini, E; Tesi, M C; Whittington, S G

    2009-01-01

    We use rigorous arguments and Monte Carlo simulations to study the thermodynamics and the topological properties of self-avoiding walks on the cubic lattice subjected to an external force f. The walks are anchored at one or both endpoints to an impenetrable plane at Z = 0 and the force is applied in the Z-direction. If a force is applied to the free endpoint of an anchored walk, then a model of pulled walks is obtained. If the walk is confined to a slab and a force is applied to the top bounding plane, then a model of stretched walks is obtained. For both models we prove the existence of the limiting free energy for any value of the force and we show that, for compressive forces, the thermodynamic properties of the two models differ substantially. For pulled walks we prove the existence of a phase transition that, by numerical simulation, we estimate to be second order and located at f = 0. By using a pattern theorem for large positive forces we show that almost all sufficiently long stretched walks are knotted. We examine the entanglement complexity of stretched and pulled walks; our numerical results show a sharp reduction with increasing pulling and stretching forces. Finally, we also examine models of pulled and stretched loops. We prove the existence of limiting free energies in these models and consider the knot probability numerically as a function of the applied pulling or stretching force

  6. Muscle co-contraction around the knee when walking with unstable shoes.

    Science.gov (United States)

    Horsak, Brian; Heller, Mario; Baca, Arnold

    2015-02-01

    Walking with unstable shoes has been discussed to decrease joint loading. Typical estimates of joint loading using an inverse dynamic approach only account for net joint moments, not considering the potential role of muscular co-contraction. Therefore, the purpose of this study was to compare muscular co-contraction levels when walking with two different unstable shoe constructions (rocker-bottom and toning shoes) compared to walking with regular shoes. For each shoe condition, 12 healthy subjects walked with both, a regular shoe and with an unstable shoe at self-selected walking speed at a 10-m walkway. Surface EMG data of selected muscles were recorded and time normalized for calculating co-contraction indices (CCI) for opposing muscle groups. Results showed an increase of co-contraction primarily for vastii and gastrocnemius muscles for the first and second half of stance when walking with an unstable shoe construction. Therefore, when using an inverse dynamic approach to analyze joint loading differences between regular shoes and unstable shoes, one should be cautious in interpreting the data, as these methods base their estimates of joint moments upon the net joint torque. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Knee Stretch Walking Method for Biped Robot: Using Toe and Heel Joints to Increase Walking Strides

    Science.gov (United States)

    Sato, Takahiko; Shimmyo, Shuhei; Nakazato, Miki; Mikami, Kei; Sato, Tomoya; Sakaino, Sho; Ohnishi, Kouhei

    This paper proposes a knee stretch walking method for biped robots; the method involves the use of the toes and heel joints to increase walking strides. A knee can be stretched by switching control variables. By a knee stretch walking with heel contacts to the ground and toe takeoffs from the ground, biped robots can increase their walking stride and speed. The validity of the proposed method is confirmed by simulation and experimental results.

  8. Spatial search by quantum walk

    International Nuclear Information System (INIS)

    Childs, Andrew M.; Goldstone, Jeffrey

    2004-01-01

    Grover's quantum search algorithm provides a way to speed up combinatorial search, but is not directly applicable to searching a physical database. Nevertheless, Aaronson and Ambainis showed that a database of N items laid out in d spatial dimensions can be searched in time of order √(N) for d>2, and in time of order √(N) poly(log N) for d=2. We consider an alternative search algorithm based on a continuous-time quantum walk on a graph. The case of the complete graph gives the continuous-time search algorithm of Farhi and Gutmann, and other previously known results can be used to show that √(N) speedup can also be achieved on the hypercube. We show that full √(N) speedup can be achieved on a d-dimensional periodic lattice for d>4. In d=4, the quantum walk search algorithm takes time of order √(N) poly(log N), and in d<4, the algorithm does not provide substantial speedup

  9. Dynamic optimization of human walking.

    Science.gov (United States)

    Anderson, F C; Pandy, M G

    2001-10-01

    A three-dimensional, neuromusculoskeletal model of the body was combined with dynamic optimization theory to simulate normal walking on level ground. The body was modeled as a 23 degree-of-freedom mechanical linkage, actuated by 54 muscles. The dynamic optimization problem was to calculate the muscle excitation histories, muscle forces, and limb motions subject to minimum metabolic energy expenditure per unit distance traveled. Muscle metabolic energy was calculated by slimming five terms: the basal or resting heat, activation heat, maintenance heat, shortening heat, and the mechanical work done by all the muscles in the model. The gait cycle was assumed to be symmetric; that is, the muscle excitations for the right and left legs and the initial and terminal states in the model were assumed to be equal. Importantly, a tracking problem was not solved. Rather only a set of terminal constraints was placed on the states of the model to enforce repeatability of the gait cycle. Quantitative comparisons of the model predictions with patterns of body-segmental displacements, ground-reaction forces, and muscle activations obtained from experiment show that the simulation reproduces the salient features of normal gait. The simulation results suggest that minimum metabolic energy per unit distance traveled is a valid measure of walking performance.

  10. Study of human walking patterns based on the parameter optimization of a passive dynamic walking robot.

    Science.gov (United States)

    Zang, Xizhe; Liu, Xinyu; Zhu, Yanhe; Zhao, Jie

    2016-04-29

    The study of human walking patterns mainly focuses on how control affects walking because control schemes are considered to be dominant in human walking. This study proposes that not only fine control schemes but also optimized body segment parameters are responsible for humans' low-energy walking. A passive dynamic walker provides the possibility of analyzing the effect of parameters on walking efficiency because of its ability to walk without any control. Thus, a passive dynamic walking model with a relatively human-like structure was built, and a parameter optimization process based on the gait sensitivity norm was implemented to determine the optimal mechanical parameters by numerical simulation. The results were close to human body parameters, thus indicating that humans can walk under a passive pattern based on their body segment parameters. A quasi-passive walking prototype was built on the basis of the optimization results. Experiments showed that a passive robot with optimized parameters could walk on level ground with only a simple hip actuation. This result implies that humans can walk under a passive pattern based on their body segment parameters with only simple control strategy implying that humans can opt to walk instinctively under a passive pattern.

  11. Comparison of two 6-minute walk tests to assess walking capacity in polio survivors.

    Science.gov (United States)

    Brehm, Merel-Anne; Verduijn, Suzan; Bon, Jurgen; Bredt, Nicoline; Nollet, Frans

    2017-11-21

    To compare walking dynamics and test-retest reliability for 2 frequently applied walk tests in polio survivors: the 6-minute walk test (6MWT) to walk as far as possible; and the 6-minute walking energy cost test (WECT) at comfortable speed. Observational study. Thirty-three polio survivors, able to walk ≥ 150 m. On the same day participants performed a 6MWT and a WECT, which were repeated 1-3 weeks later. For each test, distance walked, heart rate and reduction in speed were assessed. The mean distance walked and mean heart rate were significantly higher in the 6MWT (441 m (standard deviation) (SD 79.7); 118 bpm (SD 19.2)) compared with the WECT (366 m (SD 67.3); 103 bpm (SD 14.3)); pwalked distance was 42 m (9.7% change from the mean) and 50 m (13.7%) on the 6MWT and WECT, respectively. Both the 6MWT and the WECT are reliable to assess walking capacity in polio survivors, with slightly superior sensitivity to detect change for the 6MWT. Differences in walking dynamics confirm that the tests cannot be used interchangeably. The 6MWT is recommended for measuring maximal walking capacity and the WECT for measuring submaximal walking capacity.

  12. IMU-based ambulatory walking speed estimation in constrained treadmill and overground walking.

    Science.gov (United States)

    Yang, Shuozhi; Li, Qingguo

    2012-01-01

    This study evaluated the performance of a walking speed estimation system based on using an inertial measurement unit (IMU), a combination of accelerometers and gyroscopes. The walking speed estimation algorithm segments the walking sequence into individual stride cycles (two steps) based on the inverted pendulum-like behaviour of the stance leg during walking and it integrates the angular velocity and linear accelerations of the shank to determine the displacement of each stride. The evaluation was performed in both treadmill and overground walking experiments with various constraints on walking speed, step length and step frequency to provide a relatively comprehensive assessment of the system. Promising results were obtained in providing accurate and consistent walking speed/step length estimation in different walking conditions. An overall percentage root mean squared error (%RMSE) of 4.2 and 4.0% was achieved in treadmill and overground walking experiments, respectively. With an increasing interest in understanding human walking biomechanics, the IMU-based ambulatory system could provide a useful walking speed/step length measurement/control tool for constrained walking studies.

  13. Walking, sustainability and health: findings from a study of a Walking for Health group.

    Science.gov (United States)

    Grant, Gordon; Machaczek, Kasia; Pollard, Nick; Allmark, Peter

    2017-05-01

    Not only is it tacitly understood that walking is good for health and well-being but there is also now robust evidence to support this link. There is also growing evidence that regular short walks can be a protective factor for a range of long-term health conditions. Walking in the countryside can bring additional benefits, but access to the countryside brings complexities, especially for people with poorer material resources and from different ethnic communities. Reasons for people taking up walking as a physical activity are reasonably well understood, but factors linked to sustained walking, and therefore sustained benefit, are not. Based on an ethnographic study of a Walking for Health group in Lincolnshire, UK, this paper considers the motivations and rewards of group walks for older people. Nineteen members of the walking group, almost all with long-term conditions, took part in tape-recorded interviews about the personal benefits of walking. The paper provides insights into the links between walking as a sustainable activity and health, and why a combination of personal adaptive capacities, design elements of the walks and relational achievements of the walking group are important to this understanding. The paper concludes with some observations about the need to reframe conventional thinking about adherence to physical activity programmes. © 2017 John Wiley & Sons Ltd.

  14. Walking performance: correlation between energy cost of walking and walking participation. new statistical approach concerning outcome measurement.

    Directory of Open Access Journals (Sweden)

    Marco Franceschini

    Full Text Available Walking ability, though important for quality of life and participation in social and economic activities, can be adversely affected by neurological disorders, such as Spinal Cord Injury, Stroke, Multiple Sclerosis or Traumatic Brain Injury. The aim of this study is to evaluate if the energy cost of walking (CW, in a mixed group of chronic patients with neurological diseases almost 6 months after discharge from rehabilitation wards, can predict the walking performance and any walking restriction on community activities, as indicated by Walking Handicap Scale categories (WHS. One hundred and seven subjects were included in the study, 31 suffering from Stroke, 26 from Spinal Cord Injury and 50 from Multiple Sclerosis. The multivariable binary logistical regression analysis has produced a statistical model with good characteristics of fit and good predictability. This model generated a cut-off value of.40, which enabled us to classify correctly the cases with a percentage of 85.0%. Our research reveal that, in our subjects, CW is the only predictor of the walking performance of in the community, to be compared with the score of WHS. We have been also identifying a cut-off value of CW cost, which makes a distinction between those who can walk in the community and those who cannot do it. In particular, these values could be used to predict the ability to walk in the community when discharged from the rehabilitation units, and to adjust the rehabilitative treatment to improve the performance.

  15. Cytological artifacts masquerading interpretation

    Directory of Open Access Journals (Sweden)

    Khushboo Sahay

    2013-01-01

    Conclusions: In order to justify a cytosmear interpretation, a cytologist must be well acquainted with delayed fixation-induced cellular changes and microscopic appearances of common contaminants so as to implicate better prognosis and therapy.

  16. Interpretability in PRA

    Czech Academy of Sciences Publication Activity Database

    Bílková, Marta; De Jongh, D.; Joosten, J.J.

    2009-01-01

    Roč. 161, č. 2 (2009), s. 128-138 ISSN 0168-0072 R&D Projects: GA AV ČR IAA900090703 Grant - others:GA ČR(CZ) GA401/06/0387 Institutional research plan: CEZ:AV0Z10300504 Keywords : interpretability * arithmetic * primitive recursive arithmetic * interpretability logic Subject RIV: BA - General Mathematics Impact factor: 0.667, year: 2009

  17. Predicting Home and Community Walking Activity Poststroke.

    Science.gov (United States)

    Fulk, George D; He, Ying; Boyne, Pierce; Dunning, Kari

    2017-02-01

    Walking ability poststroke is commonly assessed using gait speed categories developed by Perry et al. The purpose of this study was to reexamine factors that predict home and community ambulators determined from real-world walking activity data using activity monitors. Secondary analyses of real-world walking activity from 2 stroke trials. Home (100-2499 steps/d), most limited community (2500-4499 steps/d), least limited community (5000-74 999), and full community (≥7500 steps/d) walking categories were developed based on normative data. Independent variables to predict walking categories were comfortable and fast gait speed, 6-minute walk test, Berg Balance Scale, Fugl Meyer, and Stroke Impact Scale. Data were analyzed using multivariate analyses to identify significant variables associated with walking categories, bootstrap method to select the most stable model and receiver-operating characteristic to identify cutoff values. Data from 441 individuals poststroke were analyzed. The 6-minute walk test, Fugl Meyer, and Berg Balance Scale combined were the strongest predictors of home versus community and limited versus unlimited community ambulators. The 6-minute walk test was the strongest individual variable in predicting home versus community (receiver-operating characteristic area under curve=0.82) and limited versus full community ambulators (receiver-operating characteristic area under curve=0.76). A comfortable gait speed of 0.49 m/s discriminated between home and community and a comfortable gait speed of 0.93 m/s discriminated between limited community and full community ambulators. The 6-minute walk test was better able to discriminate among home, limited community, and full community ambulators than comfortable gait speed. Gait speed values commonly used to distinguish between home and community walkers may overestimate walking activity. © 2017 American Heart Association, Inc.

  18. Interpreter-mediated dentistry.

    Science.gov (United States)

    Bridges, Susan; Drew, Paul; Zayts, Olga; McGrath, Colman; Yiu, Cynthia K Y; Wong, H M; Au, T K F

    2015-05-01

    The global movements of healthcare professionals and patient populations have increased the complexities of medical interactions at the point of service. This study examines interpreter mediated talk in cross-cultural general dentistry in Hong Kong where assisting para-professionals, in this case bilingual or multilingual Dental Surgery Assistants (DSAs), perform the dual capabilities of clinical assistant and interpreter. An initial language use survey was conducted with Polyclinic DSAs (n = 41) using a logbook approach to provide self-report data on language use in clinics. Frequencies of mean scores using a 10-point visual analogue scale (VAS) indicated that the majority of DSAs spoke mainly Cantonese in clinics and interpreted for postgraduates and professors. Conversation Analysis (CA) examined recipient design across a corpus (n = 23) of video-recorded review consultations between non-Cantonese speaking expatriate dentists and their Cantonese L1 patients. Three patterns of mediated interpreting indicated were: dentist designated expansions; dentist initiated interpretations; and assistant initiated interpretations to both the dentist and patient. The third, rather than being perceived as negative, was found to be framed either in response to patient difficulties or within the specific task routines of general dentistry. The findings illustrate trends in dentistry towards personalized care and patient empowerment as a reaction to product delivery approaches to patient management. Implications are indicated for both treatment adherence and the education of dental professionals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Straight and Curved Path Walking Among Older Adults in Primary Care: Associations With Fall-Related Outcomes.

    Science.gov (United States)

    Welch, Sarah A; Ward, Rachel E; Kurlinski, Laura A; Kiely, Dan K; Goldstein, Richard; VanSwearingen, Jessie; Brach, Jennifer S; Bean, Jonathan F

    2016-08-01

    Most falls among community-dwelling older adults occur while walking. Simple walking tests that require little resources and can be interpreted quickly are advocated as useful screening tools for fall prone patients. To investigate 2 clinically feasible walking tests consisting of straight- and curved-path walking and examine their associations with history of previous falls and fall-related outcomes among community-living older adults. A cross-sectional analysis was performed on baseline data from a longitudinal cohort study. Participants were recruited through primary care practices. Participants included 428 primary care patients ≥65 years of age at risk for mobility decline. Participants had a median age of 76.5 years, 67.8% were women, and 82.5% were white. Straight-path walking performance was measured as the time needed to walk a 4-meter straight path at usual pace from standstill using a stopwatch (timed to 0.1 second). Curved-path walking performance was timed while participants walked from standstill in a figure-of-8 pattern around two cones placed 5 feet apart. Multivariable negative binomial regression analyses were performed to assess the relationship between straight-path walking or curved-path walking and self-reported history of number of falls. For fall-related injuries, and fall-related hospitalizations, logistic regression models were used. In the fully adjusted model, an increase of 1 second in straight path walking time was associated with 26% greater rate of falls (rate ratio 1.26, 95% confidence interval 1.10-1.45). An increase in curved-path walking time was associated with 8% greater rate of falls (rate ratio 1.08, 95% confidence interval = 1.03-1.14). Neither walk test was associated with history of fall-related injuries or hospitalizations. Poor performance on straight- and curved-path walking performance was associated with a history of greater fall rates in the previous year but not with a history of fall-related injuries or

  20. Walking on high heels changes muscle activity and the dynamics of human walking significantly

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Svendsen, Morten Bo Søndergaard; Nørreslet, Andreas

    2012-01-01

    The aim of the study was to investigate the distribution of net joint moments in the lower extremities during walking on high-heeled shoes compared with barefooted walking at identical speed. Fourteen female subjects walked at 4 km/h across three force platforms while they were filmed by five...... digital video cameras operating at 50 frames/second. Both barefooted walking and walking on high-heeled shoes (heel height: 9 cm) were recorded. Net joint moments were calculated by 3D inverse dynamics. EMG was recorded from eight leg muscles. The knee extensor moment peak in the first half of the stance...

  1. Walking economy in people with Parkinson's disease.

    Science.gov (United States)

    Christiansen, Cory L; Schenkman, Margaret L; McFann, Kim; Wolfe, Pamela; Kohrt, Wendy M

    2009-07-30

    Gait dysfunction is an early problem identified by patients with Parkinson's disease (PD). Alterations in gait may result in an increase in the energy cost of walking (i.e., walking economy). The purpose of this study was to determine whether walking economy is atypical in patients with PD when compared with healthy controls. A secondary purpose was to evaluate the associations of age, sex, and level of disease severity with walking economy in patients with PD. The rate of oxygen consumption (VO(2)) and other responses to treadmill walking were compared in 90 patients (64.4 +/- 10.3 years) and 44 controls (64.6 +/- 7.3 years) at several walking speeds. Pearson correlation coefficients (r) were calculated to determine relationships of age, sex, and disease state with walking economy in PD patients. Walking economy was significantly worse in PD patients than in controls at all speeds above 1.0 mph. Across all speeds, VO(2) was 6 to 10% higher in PD patients. Heart rate, minute ventilation, respiratory exchange ratio, and rating of perceived exertion were correspondingly elevated. No significant relationship of age, sex, or UPDRS score with VO(2) was found for patients with PD. The findings suggest that the physiologic stress of daily physical activities is increased in patients with early to mid-stage PD, and this may contribute to the elevated level of fatigue that is characteristic of PD. Copyright 2009 Movement Disorder Society.

  2. Nordic walking improves mobility in Parkinson's disease.

    NARCIS (Netherlands)

    Eijkeren, F.J. van; Reijmers, R.S.; Kleinveld, M.J.; Minten, A.; Bruggen, J.P.; Bloem, B.R.

    2008-01-01

    Nordic walking may improve mobility in Parkinson's disease (PD). Here, we examined whether the beneficial effects persist after the training period. We included 19 PD patients [14 men; mean age 67.0 years (range 58-76); Hoehn and Yahr stage range 1-3] who received a 6-week Nordic walking exercise

  3. Rhythmic walking interactions with auditory feedback

    DEFF Research Database (Denmark)

    Jylhä, Antti; Serafin, Stefania; Erkut, Cumhur

    2012-01-01

    Walking is a natural rhythmic activity that has become of interest as a means of interacting with software systems such as computer games. Therefore, designing multimodal walking interactions calls for further examination. This exploratory study presents a system capable of different kinds of int...

  4. Walking in Place Through Virtual Worlds

    DEFF Research Database (Denmark)

    Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

    2016-01-01

    Immersive virtual reality (IVR) is seemingly on the verge of entering the homes of consumers. Enabling users to walk through virtual worlds in a limited physical space presents a challenge. With an outset in a taxonomy of virtual travel techniques, we argue that Walking-in-Place (WIP) techniques ...

  5. Cognitive Resource Demands of Redirected Walking.

    Science.gov (United States)

    Bruder, Gerd; Lubas, Paul; Steinicke, Frank

    2015-04-01

    Redirected walking allows users to walk through a large-scale immersive virtual environment (IVE) while physically remaining in a reasonably small workspace. Therefore, manipulations are applied to virtual camera motions so that the user's self-motion in the virtual world differs from movements in the real world. Previous work found that the human perceptual system tolerates a certain amount of inconsistency between proprioceptive, vestibular and visual sensation in IVEs, and even compensates for slight discrepancies with recalibrated motor commands. Experiments showed that users are not able to detect an inconsistency if their physical path is bent with a radius of at least 22 meters during virtual straightforward movements. If redirected walking is applied in a smaller workspace, manipulations become noticeable, but users are still able to move through a potentially infinitely large virtual world by walking. For this semi-natural form of locomotion, the question arises if such manipulations impose cognitive demands on the user, which may compete with other tasks in IVEs for finite cognitive resources. In this article we present an experiment in which we analyze the mutual influence between redirected walking and verbal as well as spatial working memory tasks using a dual-tasking method. The results show an influence of redirected walking on verbal as well as spatial working memory tasks, and we also found an effect of cognitive tasks on walking behavior. We discuss the implications and provide guidelines for using redirected walking in virtual reality laboratories.

  6. Identifying particular places through experimental walking

    Directory of Open Access Journals (Sweden)

    Henrik Schultz

    2016-11-01

    Full Text Available Experimental walking can be used to identify particular places, design strategies and spatial visions for urban landscapes. Walking designers can explore sites and, in particular, their temporal dynamics and atmospheric particularities – both essential elements in making particular places. This article illustrates the benefits of this method, using the changing German city of Freiburg as an example.

  7. The environmental benefits of bicycling and walking.

    Science.gov (United States)

    1993-01-01

    Bicycling and walking are the two major non-fuel-consuming, non-polluting : forms of transportation in the United States. Millions of Americans ride : bicycles and/or walk for a wide variety of purposes --- commuting to work, as : part of their job, ...

  8. Sites of Sign-Production and Interpretation

    Directory of Open Access Journals (Sweden)

    Maria-Ana Tupan

    2016-03-01

    Full Text Available T.S. Eliot’s query in The Waste Land, “Who is the third who walks always beside you?” may be said to sum up the hermeneutic situation of any language act, whether of sign production or interpretation. Whereas traditional topoi of expressionist aesthetics, such as the artist’s subjectivity, empirical psychology, truthfulness, intentionality, etc. have become irrelevant in the heteroglottic discourse of the most famous dirge on the decaying West, Eliot’s awareness of the matrical role of cultural semiosis allows us to place him among the founding fathers of semiotic aesthetics. The anagnorisis episode in The Waste Land is one of appropriate reading of the body of Christ through knowledge of the crucifixion scene and associated symbolism.Rooted in the insights of Charles Peirce Sanders and Charles Morris, and enlarged by post-war contributors, such as Roland Barthes, Umberto Eco, Michael B. Hardt, Richard Rudner, Foucault, Vattimo, Baudrillard and Deleuze, the semiotic, cultural materialist, or genetic approach  to art makes interpretation dependent on a mediating third (Peirce: the Interpretant, which is variously related to context, regime of signification, episteme, schemata, generic convention, structure of feeling, triangulation of desire ...

  9. A weighted random walk approximation to fractional Brownian motion

    OpenAIRE

    Lindstrøm, Tom

    2007-01-01

    We present a random walk approximation to fractional Brownian motion where the increments of the fractional random walk are defined as a weighted sum of the past increments of a Bernoulli random walk.

  10. A random walk approximation to fractional Brownian motion

    OpenAIRE

    Lindstrøm, Tom

    2007-01-01

    We present a random walk approximation to fractional Brownian motion where the increments of the fractional random walk are defined as a weighted sum of the past increments of a Bernoulli random walk.

  11. Go naked: diapers affect infant walking.

    Science.gov (United States)

    Cole, Whitney G; Lingeman, Jesse M; Adolph, Karen E

    2012-11-01

    In light of cross-cultural and experimental research highlighting effects of childrearing practices on infant motor skill, we asked whether wearing diapers, a seemingly innocuous childrearing practice, affects infant walking. Diapers introduce bulk between the legs, potentially exacerbating infants' poor balance and wide stance. We show that walking is adversely affected by old-fashioned cloth diapers, and that even modern disposable diapers - habitually worn by most infants in the sample - incur a cost relative to walking naked. Infants displayed less mature gait patterns and more missteps and falls while wearing diapers. Thus, infants' own diapers constitute an ongoing biomechanical perturbation while learning to walk. Furthermore, shifts in diapering practices may have contributed to historical and cross-cultural differences in infant walking. © 2012 Blackwell Publishing Ltd.

  12. Efficient quantum walk on a quantum processor.

    Science.gov (United States)

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L; Wang, Jingbo B; Matthews, Jonathan C F

    2016-05-05

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor.

  13. Design Issues for Hexapod Walking Robots

    Directory of Open Access Journals (Sweden)

    Franco Tedeschi

    2014-06-01

    Full Text Available Hexapod walking robots have attracted considerable attention for several decades. Many studies have been carried out in research centers, universities and industries. However, only in the recent past have efficient walking machines been conceived, designed and built with performances that can be suitable for practical applications. This paper gives an overview of the state of the art on hexapod walking robots by referring both to the early design solutions and the most recent achievements. Careful attention is given to the main design issues and constraints that influence the technical feasibility and operation performance. A design procedure is outlined in order to systematically design a hexapod walking robot. In particular, the proposed design procedure takes into account the main features, such as mechanical structure and leg configuration, actuating and driving systems, payload, motion conditions, and walking gait. A case study is described in order to show the effectiveness and feasibility of the proposed design procedure.

  14. Efficient quantum walk on a quantum processor

    Science.gov (United States)

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L.; Wang, Jingbo B.; Matthews, Jonathan C. F.

    2016-01-01

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor. PMID:27146471

  15. Quantum walk with one variable absorbing boundary

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feiran [Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, Shaanxi Province, Xi' an Jiaotong University, Xi' an 710049 (China); Department of Applied Physics, School of Science, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Pei, E-mail: zhangpei@mail.ustc.edu.cn [Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, Shaanxi Province, Xi' an Jiaotong University, Xi' an 710049 (China); Department of Applied Physics, School of Science, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli [Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, Shaanxi Province, Xi' an Jiaotong University, Xi' an 710049 (China); Department of Applied Physics, School of Science, Xi' an Jiaotong University, Xi' an 710049 (China)

    2017-01-15

    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks. - Highlights: • A novel scheme about quantum walk with variable boundary is proposed. • The analytical results of the survival probability from the absorbing boundary. • The behavior of survival probability under different boundary conditions. • The influence of different initial coin states on the survival probability.

  16. Exact and Efficient Sampling of Conditioned Walks

    Science.gov (United States)

    Adorisio, Matteo; Pezzotta, Alberto; de Mulatier, Clélia; Micheletti, Cristian; Celani, Antonio

    2018-01-01

    A computationally challenging and open problem is how to efficiently generate equilibrated samples of conditioned walks. We present here a general stochastic approach that allows one to produce these samples with their correct statistical weight and without rejections. The method is illustrated for a jump process conditioned to evolve within a cylindrical channel and forced to reach one of its ends. We obtain analytically the exact probability density function of the jumps and offer a direct method for gathering equilibrated samples of a random walk conditioned to stay in a channel with suitable boundary conditions. Unbiased walks of arbitrary length can thus be generated with linear computational complexity—even when the channel width is much smaller than the typical bond length of the unconditioned walk. By profiling the metric properties of the generated walks for various bond lengths we characterize the crossover between weak and strong confinement regimes with great detail.

  17. Encouraging physical activity through dog walking: why don't some owners walk with their dog?

    Science.gov (United States)

    Cutt, Hayley; Giles-Corti, Billie; Knuiman, Matthew

    2008-02-01

    To identify factors associated with owners not walking with their dog. Dog owners (n=629) taking part in the RESIDE study, Perth, Western Australia completed a self-administered questionnaire in 2005-06 that included items about the dog, dog-owner relationship, dog walking and intrapersonal and environmental factors associated with dog walking. Physical activity data were also collected using NPAQ. Overall, 23% of dog owners did not walk with their dog. More dog walkers achieved 150 min of physical activity/week than owners who did not walk with their dog (72% vs. 44%, p<0.001). Not walking with a dog was significantly more likely in owners who did not perceive that their dog provided motivation (OR 9.60, 95% CI: 4.37, 21.08) or social support (OR 10.84, 95% CI: 5.15, 22.80) to walk, independent of other well-known correlates of physical activity. There would be a significant impact on community physical activity levels if owners who do not walk with their dog could be persuaded to begin dog walking. Understanding the factors that discourage or facilitate owners to walk with their dog will assist in tailoring interventions designed to encourage both the uptake and maintenance of regular dog walking.

  18. Talk the Walk: Does Socio-Cognitive Resource Reallocation Facilitate the Development of Walking?

    Science.gov (United States)

    Geva, Ronny; Orr, Edna

    2016-01-01

    Walking is of interest to psychology, robotics, zoology, neuroscience and medicine. Human's ability to walk on two feet is considered to be one of the defining characteristics of hominoid evolution. Evolutionary science propses that it emerged in response to limited environmental resources; yet the processes supporting its emergence are not fully understood. Developmental psychology research suggests that walking elicits cognitive advancements. We postulate that the relationship between cognitive development and walking is a bi-directional one; and further suggest that the initiation of novel capacities, such as walking, is related to internal socio-cognitive resource reallocation. We shed light on these notions by exploring infants' cognitive and socio-communicative outputs prospectively from 6-18 months of age. Structured bi/tri weekly evaluations of symbolic and verbal development were employed in an urban cohort (N = 9) for 12 months, during the transition from crawling to walking. Results show links between preemptive cognitive changes in socio-communicative output, symbolic-cognitive tool-use processes, and the age of emergence of walking. Plots of use rates of lower symbolic play levels before and after emergence of new skills illustrate reductions in use of previously attained key behaviors prior to emergence of higher symbolic play, language and walking. Further, individual differences in age of walking initiation were strongly related to the degree of reductions in complexity of object-use (r = .832, p walking; r = .729, p walking initiation (r = .901, pwalking.

  19. Effects of walking and strength training on walking capacity in individuals with claudication: meta-analysis

    Directory of Open Access Journals (Sweden)

    Alessandra de Souza Miranda

    2013-06-01

    Full Text Available CONTEXT: Over the past few years, several clinical trials have been performed to analyze the effects of exercise training on walking ability in patients with intermittent claudication (IC. However, it remains unclear which type of physical exercise provides the maximum benefits in terms of walking ability. OBJECTIVE: To analyze, by means of a meta-analysis, the effects of walking and strength training on the walking capacity in patients with IC. METHODS: Papers analyzing the effects of walking and strength training programs in patients with IC were browsed on the Medline, Lilacs, and Cochrane databases. Randomized clinical trials scoring >4 on the Physiotherapy Evidence Database (PEDro scale and assessing claudication distance (CD and total walking distance (TWD were included in the review. RESULTS: Walking and strength training yielded increases in CD and TWD (P < 0.05. However, walking training yielded greater increases than strength training (P = 0.02. CONCLUSION: Walking and strength training improve walking capacity in patients with IC. However, greater improvements in TWD are obtained with walking training.

  20. Biomechanical parameters in lower limbs during natural walking and Nordic walking at different speeds.

    Science.gov (United States)

    Dziuba, Alicja K; Żurek, Grzegorz; Garrard, Ian; Wierzbicka-Damska, Iwona

    2015-01-01

    Nordic Walking (NW) is a sport that has a number of benefits as a rehabilitation method. It is performed with specially designed poles and has been often recommended as a physical activity that helps reduce the load to limbs. However, some studies have suggested that these findings might be erroneous. The aim of this paper was to compare the kinematic, kinetic and dynamic parameters of lower limbs between Natural Walking (W) and Nordic Walking (NW) at both low and high walking speeds. The study used a registration system, BTS Smart software and Kistler platform. Eleven subjects walked along a 15-metre path at low (below 2 m⋅s-1) and high (over 2 m⋅s-1) walking speeds. The Davis model was employed for calculations of kinematic, kinetic and dynamic parameters of lower limbs. With constant speed, the support given by Nordic Walking poles does not make the stroke longer and there is no change in pelvic rotation either. The only change observed was much bigger pelvic anteversion in the sagittal plane during fast NW. There were no changes in forces, power and muscle torques in lower limbs. The study found no differences in kinematic, kinetic and dynamic parameters between Natural Walking (W) and Nordic Walking (NW). Higher speeds generate greater ground reaction forces and muscle torques in lower limbs. Gait parameters depend on walking speed rather than on walking style.

  1. Symbolic walk in regular networks

    International Nuclear Information System (INIS)

    Ermann, Leonardo; Carlo, Gabriel G

    2015-01-01

    We find that a symbolic walk (SW)—performed by a walker with memory given by a Bernoulli shift—is able to distinguish between the random or chaotic topology of a given network. We show this result by means of studying the undirected baker network, which is defined by following the Ulam approach for the baker transformation in order to introduce the effect of deterministic chaos into its structure. The chaotic topology is revealed through the central role played by the nodes associated with the positions corresponding to the shortest periodic orbits of the generating map. They are the overwhelmingly most visited nodes in the limit cycles at which the SW asymptotically arrives. Our findings contribute to linking deterministic chaotic dynamics with the properties of networks constructed using the Ulam approach. (paper)

  2. Snell's law and walking droplets

    Science.gov (United States)

    Bush, John; Pucci, Giuseppe; Aubin, Benjamin; Brun, Pierre-Thomas; Faria, Luiz

    2016-11-01

    Droplets walking on the surface of a vibrating bath have been shown to exhibit a number of quantum-like features. We here present the results of a combined experimental and theoretical investigation of such droplets crossing a linear step corresponding to a reduction in bath depth. When the step is sufficiently large, the walker reflects off the step; otherwise, it is refracted as it crosses the step. Particular attention is given to an examination of the regime in which the droplet obeys a form of Snell's Law, a behavior captured in accompanying simulations. Attempts to provide theoretical rationale for the dependence of the effective refractive index on the system parameters are described. Supported by NSF through CMMI-1333242.

  3. Random walks on reductive groups

    CERN Document Server

    Benoist, Yves

    2016-01-01

    The classical theory of Random Walks describes the asymptotic behavior of sums of independent identically distributed random real variables. This book explains the generalization of this theory to products of independent identically distributed random matrices with real coefficients. Under the assumption that the action of the matrices is semisimple – or, equivalently, that the Zariski closure of the group generated by these matrices is reductive - and under suitable moment assumptions, it is shown that the norm of the products of such random matrices satisfies a number of classical probabilistic laws. This book includes necessary background on the theory of reductive algebraic groups, probability theory and operator theory, thereby providing a modern introduction to the topic.

  4. Localized Smart-Interpretation

    Science.gov (United States)

    Lundh Gulbrandsen, Mats; Mejer Hansen, Thomas; Bach, Torben; Pallesen, Tom

    2014-05-01

    The complex task of setting up a geological model consists not only of combining available geological information into a conceptual plausible model, but also requires consistency with availably data, e.g. geophysical data. However, in many cases the direct geological information, e.g borehole samples, are very sparse, so in order to create a geological model, the geologist needs to rely on the geophysical data. The problem is however, that the amount of geophysical data in many cases are so vast that it is practically impossible to integrate all of them in the manual interpretation process. This means that a lot of the information available from the geophysical surveys are unexploited, which is a problem, due to the fact that the resulting geological model does not fulfill its full potential and hence are less trustworthy. We suggest an approach to geological modeling that 1. allow all geophysical data to be considered when building the geological model 2. is fast 3. allow quantification of geological modeling. The method is constructed to build a statistical model, f(d,m), describing the relation between what the geologists interpret, d, and what the geologist knows, m. The para- meter m reflects any available information that can be quantified, such as geophysical data, the result of a geophysical inversion, elevation maps, etc... The parameter d reflects an actual interpretation, such as for example the depth to the base of a ground water reservoir. First we infer a statistical model f(d,m), by examining sets of actual interpretations made by a geological expert, [d1, d2, ...], and the information used to perform the interpretation; [m1, m2, ...]. This makes it possible to quantify how the geological expert performs interpolation through f(d,m). As the geological expert proceeds interpreting, the number of interpreted datapoints from which the statistical model is inferred increases, and therefore the accuracy of the statistical model increases. When a model f

  5. The Interpretive Function

    DEFF Research Database (Denmark)

    Agerbo, Heidi

    2017-01-01

    Approximately a decade ago, it was suggested that a new function should be added to the lexicographical function theory: the interpretive function(1). However, hardly any research has been conducted into this function, and though it was only suggested that this new function was relevant to incorp......Approximately a decade ago, it was suggested that a new function should be added to the lexicographical function theory: the interpretive function(1). However, hardly any research has been conducted into this function, and though it was only suggested that this new function was relevant...... to incorporate into lexicographical theory, some scholars have since then assumed that this function exists(2), including the author of this contribution. In Agerbo (2016), I present arguments supporting the incorporation of the interpretive function into the function theory and suggest how non-linguistic signs...... can be treated in specific dictionary articles. However, in the current article, due to the results of recent research, I argue that the interpretive function should not be considered an individual main function. The interpretive function, contrary to some of its definitions, is not connected...

  6. Walk Score®: associations with purposive walking in recent Cuban immigrants.

    Science.gov (United States)

    Brown, Scott C; Pantin, Hilda; Lombard, Joanna; Toro, Matthew; Huang, Shi; Plater-Zyberk, Elizabeth; Perrino, Tatiana; Perez-Gomez, Gianna; Barrera-Allen, Lloyd; Szapocznik, José

    2013-08-01

    Walk Score® is a nationally and publicly available metric of neighborhood walkability based on proximity to amenities (e.g., retail, food, schools). However, few studies have examined the relationship of Walk Score to walking behavior. To examine the relationship of Walk Score to walking behavior in a sample of recent Cuban immigrants, who overwhelmingly report little choice in their selection of neighborhood built environments when they arrive in the U.S. Participants were 391 recent healthy Cuban immigrants (mean age=37.1 years) recruited within 90 days of arrival in the U.S., and assessed within 4 months of arrival (mean=41.0 days in the U.S.), who resided throughout Miami-Dade County FL. Data on participants' addresses, walking, and sociodemographics were collected prospectively from 2008 to 2010. Analyses conducted in 2011 examined the relationship of Walk Score for each participant's residential address in the U.S. to purposive walking, controlling for age, gender, education, BMI, days in the U.S., and habitual physical activity level in Cuba. For each 10-point increase in Walk Score, adjusting for covariates, there was a significant 19% increase in the likelihood of purposive walking, a 26% increase in the likelihood of meeting physical activity recommendations by walking, and 27% more minutes walked in the previous week. Results suggest that Walk Score is associated with walking in a sample of recent immigrants who initially had little choice in where they lived in the U.S. These results support existing guidelines indicating that mixed land use (such as parks and restaurants near homes) should be included when designing walkable communities. Copyright © 2013 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  7. Interpretation of panoramic radiographs.

    Science.gov (United States)

    Perschbacher, Susanne

    2012-03-01

    Panoramic radiography has become a commonly used imaging modality in dental practice and can be a valuable diagnostic tool in the dentist's armamentarium. However, the panoramic image is a complex projection of the jaws with multiple superimpositions and distortions which may be exacerbated by technical errors in image acquisition. Furthermore, the panoramic radiograph depicts numerous anatomic structures outside of the jaws which may create additional interpretation challenges. Successful interpretation of panoramic radiographs begins with an understanding of the normal anatomy of the head and neck and how it is depicted in this image type. This article will describe how osseous structures, soft tissues, air spaces and ghost shadows contribute to the final panoramic image. A systematic and repeated approach to examining panoramic radiographs, which is recommended to ensure that critical findings are not overlooked, is also outlined. Examples of challenging interpretations, including variations of anatomy, artefacts and disease, are presented to illustrate these concepts. © 2012 Australian Dental Association.

  8. The Interpretive Function

    DEFF Research Database (Denmark)

    Agerbo, Heidi

    2017-01-01

    to acting and therefore the only difference between reception and interpretation is that they work with different types of sign. However, the type of sign is not relevant for a function, or rather, it should not be a criterion for distinguishing between functions. The lemma selection for the communicative......Approximately a decade ago, it was suggested that a new function should be added to the lexicographical function theory: the interpretive function(1). However, hardly any research has been conducted into this function, and though it was only suggested that this new function was relevant...... to incorporate into lexicographical theory, some scholars have since then assumed that this function exists(2), including the author of this contribution. In Agerbo (2016), I present arguments supporting the incorporation of the interpretive function into the function theory and suggest how non-linguistic signs...

  9. Reflections and Interpretations

    DEFF Research Database (Denmark)

    Reflections and Interpretations is an anthology on The Freedom Writers’ methodology. It is an anthology for all those with a professional need for texts explaining, not only how The Freedom Writers’ tools are being used, but also why they work so convincingly well. It is not an anthology of guide......Reflections and Interpretations is an anthology on The Freedom Writers’ methodology. It is an anthology for all those with a professional need for texts explaining, not only how The Freedom Writers’ tools are being used, but also why they work so convincingly well. It is not an anthology...

  10. Conjunctive interpretations of disjunctions

    Directory of Open Access Journals (Sweden)

    Robert van Rooij

    2010-09-01

    Full Text Available In this extended commentary I discuss the problem of how to account for "conjunctive" readings of some sentences with embedded disjunctions for globalist analyses of conversational implicatures. Following Franke (2010, 2009, I suggest that earlier proposals failed, because they did not take into account the interactive reasoning of what else the speaker could have said, and how else the hearer could have interpreted the (alternative sentence(s. I show how Franke's idea relates to more traditional pragmatic interpretation strategies. doi:10.3765/sp.3.11 BibTeX info

  11. Interpretations of Quantum Mechanics

    Directory of Open Access Journals (Sweden)

    Pickl Peter

    2014-04-01

    Full Text Available The problems of modern physics are man made. The Copenhagen version of quantum mechanics is formulated in a vague prosaic way, inconsistencies and paradoxes are the price. New interpretations try to solve the problem, however a reformulation rather than an interpretation is needed. In this manuscript I will point out, where the Copenhagen formulation of quantum mechanics is flawed and how one can make sense out of it. Then I will show, that it is possible to give a precise formulation of quantum mechanics without losing its compelling ability in describing experiments.

  12. Interpretations of Quantum Mechanics

    Science.gov (United States)

    Pickl, Peter

    2014-04-01

    The problems of modern physics are man made. The Copenhagen version of quantum mechanics is formulated in a vague prosaic way, inconsistencies and paradoxes are the price. New interpretations try to solve the problem, however a reformulation rather than an interpretation is needed. In this manuscript I will point out, where the Copenhagen formulation of quantum mechanics is flawed and how one can make sense out of it. Then I will show, that it is possible to give a precise formulation of quantum mechanics without losing its compelling ability in describing experiments.

  13. Translation, Interpreting and Lexicography

    DEFF Research Database (Denmark)

    Dam, Helle Vrønning; Tarp, Sven

    2018-01-01

    Translation, interpreting and lexicography represent three separate areas of human activity, each of them with its own theories, models and methods and, hence, with its own disciplinary underpinnings. At the same time, all three disciplines are characterized by a marked interdisciplinary dimension...... in the sense that their practice fields are typically ‘about something else’. Translators may, for example, be called upon to translate medical texts, and interpreters may be assigned to work on medical speeches. Similarly, practical lexicography may produce medical dictionaries. In this perspective, the three...

  14. Walking dreams in congenital and acquired paraplegia.

    Science.gov (United States)

    Saurat, Marie-Thérèse; Agbakou, Maité; Attigui, Patricia; Golmard, Jean-Louis; Arnulf, Isabelle

    2011-12-01

    To test if dreams contain remote or never-experienced motor skills, we collected during 6 weeks dream reports from 15 paraplegics and 15 healthy subjects. In 9/10 subjects with spinal cord injury and in 5/5 with congenital paraplegia, voluntary leg movements were reported during dream, including feelings of walking (46%), running (8.6%), dancing (8%), standing up (6.3%), bicycling (6.3%), and practicing sports (skiing, playing basketball, swimming). Paraplegia patients experienced walking dreams (38.2%) just as often as controls (28.7%). There was no correlation between the frequency of walking dreams and the duration of paraplegia. In contrast, patients were rarely paraplegic in dreams. Subjects who had never walked or stopped walking 4-64 years prior to this study still experience walking in their dreams, suggesting that a cerebral walking program, either genetic or more probably developed via mirror neurons (activated when observing others performing an action) is reactivated during sleep. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Walking training with cueing of cadence improves walking speed and stride length after stroke more than walking training alone: a systematic review.

    Science.gov (United States)

    Nascimento, Lucas R; de Oliveira, Camila Quel; Ada, Louise; Michaelsen, Stella M; Teixeira-Salmela, Luci F

    2015-01-01

    After stroke, is walking training with cueing of cadence superior to walking training alone in improving walking speed, stride length, cadence and symmetry? Systematic review with meta-analysis of randomised or controlled trials. Adults who have had a stroke. Walking training with cueing of cadence. Four walking outcomes were of interest: walking speed, stride length, cadence and symmetry. This review included seven trials involving 211 participants. Because one trial caused substantial statistical heterogeneity, meta-analyses were conducted with and without this trial. Walking training with cueing of cadence improved walking speed by 0.23 m/s (95% CI 0.18 to 0.27, I(2)=0%), stride length by 0.21 m (95% CI 0.14 to 0.28, I(2)=18%), cadence by 19 steps/minute (95% CI 14 to 23, I(2)=40%), and symmetry by 15% (95% CI 3 to 26, random effects) more than walking training alone. This review provides evidence that walking training with cueing of cadence improves walking speed and stride length more than walking training alone. It may also produce benefits in terms of cadence and symmetry of walking. The evidence appears strong enough to recommend the addition of 30 minutes of cueing of cadence to walking training, four times a week for 4 weeks, in order to improve walking in moderately disabled individuals with stroke. PROSPERO (CRD42013005873). Copyright © 2014 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

  16. Walking modality, but not task difficulty, influences the control of dual-task walking.

    Science.gov (United States)

    Wrightson, J G; Smeeton, N J

    2017-10-01

    During dual-task gait, changes in the stride-to-stride variability of stride time (STV) are suggested to represent the allocation of cognitive control to walking [1]. However, contrasting effects have been reported for overground and treadmill walking, which may be due to differences in the relative difficulty of the dual task. Here we compared the effect of overground and treadmill dual-task walking on STV in 18 healthy adults. Participants walked overground and on a treadmill for 120s during single-task (walking only) and dual-task (walking whilst performing serial subtractions in sevens) conditions. Dual-task effects on STV, cognitive task (serial subtraction) performance and perceived task difficulty were compared between walking modalities. STV was increased during overground dual-task walking, but was unchanged during treadmill dual-task walking. There were no differences in cognitive task performance or perceived task difficulty. These results show that gait is controlled differently during overground and treadmill dual-task walking. However, these differences are not solely due to differences in task difficulty, and may instead represent modality dependent control strategies. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Does long-distance walking improve or deteriorate walking stability of transtibial amputees?

    Science.gov (United States)

    Wong, Duo Wai-Chi; Lam, Wing Kai; Yeung, L F; Lee, Winson C C

    2015-10-01

    Falls are common in transtibial amputees which are linked to their poor stability. While amputees are encouraged to walk more, they are more vulnerable to fatigue which leads to even poorer walking stability. The objective of this study was to evaluate the dynamic stability of amputees after long-distance walking. Six male unilateral transtibial amputees (age: 53 (SD: 8.8); height: 170cm (SD: 3.4); weight: 75kg (SD: 4.7)) performed two sessions (30minutes each) of treadmill walking, separated by a short period of gait tests. Gait tests were performed before the walking (baseline) and after each session of treadmill walking. Gait parameters and their variability across repeated steps at each of the three conditions were computed. There were no significant differences in walking speed, step length, stance time, time of occurrence, and magnitude of peak angular velocities of the knee and hip joint (P>0.05). However, variability of knee and hip angular velocity after 30-minute walking was significantly higher than the baseline (Pamputees to restore their walking stability after further continuous walking. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Increasing Walking in the Hartsfield-Jackson Atlanta International Airport: The Walk to Fly Study.

    Science.gov (United States)

    Fulton, Janet E; Frederick, Ginny M; Paul, Prabasaj; Omura, John D; Carlson, Susan A; Dorn, Joan M

    2017-07-01

    To test the effectiveness of a point-of-decision intervention to prompt walking, versus motorized transport, in a large metropolitan airport. We installed point-of-decision prompt signage at 4 locations in the airport transportation mall at Hartsfield-Jackson Atlanta International Airport (Atlanta, GA) at the connecting corridor between airport concourses. Six ceiling-mounted infrared sensors counted travelers entering and exiting the study location. We collected traveler counts from June 2013 to May 2016 when construction was present and absent (preintervention period: June 2013-September 2014; postintervention period: September 2014-May 2016). We used a model that incorporated weekly walking variation to estimate the intervention effect on walking. There was an 11.0% to 16.7% relative increase in walking in the absence of airport construction where 580 to 810 more travelers per day chose to walk. Through May 2016, travelers completed 390 000 additional walking trips. The Walk to Fly study demonstrated a significant and sustained increase in the number of airport travelers choosing to walk. Providing signage about options to walk in busy locations where reasonable walking options are available may improve population levels of physical activity and therefore improve public health.

  19. Effects of a Flexibility and Relaxation Programme, Walking, and Nordic Walking on Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    I. Reuter

    2011-01-01

    Full Text Available Symptoms of Parkinson's disease (PD progress despite optimized medical treatment. The present study investigated the effects of a flexibility and relaxation programme, walking, and Nordic walking (NW on walking speed, stride length, stride length variability, Parkinson-specific disability (UPDRS, and health-related quality of life (PDQ 39. 90 PD patients were randomly allocated to the 3 treatment groups. Patients participated in a 6-month study with 3 exercise sessions per week, each lasting 70 min. Assessment after completion of the training showed that pain was reduced in all groups, and balance and health-related quality of life were improved. Furthermore, walking, and Nordic walking improved stride length, gait variability, maximal walking speed, exercise capacity at submaximal level, and PD disease-specific disability on the UPDRS in addition. Nordic walking was superior to the flexibility and relaxation programme and walking in improving postural stability, stride length, gait pattern and gait variability. No significant injuries occurred during the training. All patients of the Nordic walking group continued Nordic walking after completing the study.

  20. Interpreting the Constitution.

    Science.gov (United States)

    Brennan, William J., Jr.

    1987-01-01

    Discusses constitutional interpretations relating to capital punishment and protection of human dignity. Points out the document's effectiveness in creating a new society by adapting its principles to current problems and needs. Considers two views of the Constitution that lead to controversy over the legitimacy of judicial decisions. (PS)

  1. Listening and Message Interpretation

    Science.gov (United States)

    Edwards, Renee

    2011-01-01

    Message interpretation, the notion that individuals assign meaning to stimuli, is related to listening presage, listening process, and listening product. As a central notion of communication, meaning includes (a) denotation and connotation, and (b) content and relational meanings, which can vary in ambiguity and vagueness. Past research on message…

  2. Interpretation as conflict resolution

    NARCIS (Netherlands)

    Swart, Henriëtte de; Zwart, J.

    Semantic interpretation is not a simple process. When we want to know what a given sentence means, more is needed than just a simple ‘adding up’ of the meanings of the component words. Not only can the words in a sentence interact and conflict with each other, but also with the linguistic and

  3. Interpretations of Greek Mythology

    NARCIS (Netherlands)

    Bremmer, Jan

    1987-01-01

    This collection of original studies offers new interpretations of some of the best known characters and themes of Greek mythology, reflecting the complexity and fascination of the Greek imagination. Following analyses of the concept of myth and the influence of the Orient on Greek mythology, the

  4. Interpretability in PRA

    NARCIS (Netherlands)

    Bílková, M.; de Jongh, D.; Joosten, J.J.

    2009-01-01

    In this paper, we study IL(PRA), the interpretability logic of PRA. As PRA is neither an essentially reflexive theory nor finitely axiomatizable, the two known arithmetical completeness results do not apply to PRA: IL(PRA) is not ILM or ILP. IL(PRA) does, of course, contain all the principles known

  5. Food sustainability: diverging interpretations

    NARCIS (Netherlands)

    Aiking, H.; de Boer, J.

    2004-01-01

    The concept of sustainability in general and food sustainability, in particular, entails many aspects and many interpretations. During a conference on food sustainability a broad, multidisciplinary picture was painted and many key issues were dealt with, from ecology, economy and society. In

  6. Urban walking: Perspectives of locals and tourists

    Directory of Open Access Journals (Sweden)

    Farkić Jelena

    2015-01-01

    Full Text Available Urban planners and architects have done extensive research on walk ability: what it means and how it correlates with urban design and quality of life of the locals, however, it has been hitherto neglected from the aspect of tourism studies. Many cities worldwide are or tend to be walkable as this leads to more sustainable and prosperous communities. In addition, walking-friendly environments greatly cater for leisure and tourism, as in many cities, walking is an integral part of tourist experience. Therefore, tourism industry can be of tremendous help for the city authorities in understanding walkers' needs and experiences. Taking into account both the locals and tourists, this research sought to: (1 determine the most frequently utilized modes of transportation in Novi Sad in Serbia and Koper in Slovenia; (2 assess thier reasons for walking and perception of the quality of pedestrian infrastructure; and (3 evaluate the psychometric properties of the questionnaire designed for the purpose of this study. The results show that the great majority of respondents walk in these two cities. The locals walk primarily to achieve physical fitness, whereas tourists walk primarily to explore the urban spaces. This makes more space for tourism as it combines a competitive supply able to meet visitors' expectations with a positive contribution to the sustainable development of cities and well-being of their residents. Furthermore, this study contributes to emphasizing walking as a sustainable form of mobility in urban environment and can be the impetus for profiling Novi Sad and Koper as walking-friendly cities.

  7. Decreased Variability of the 6-Minute Walk Test by Heart Rate Correction in Patients with Neuromuscular Disease

    DEFF Research Database (Denmark)

    Prahm, Kira Philipsen; Witting, Nanna; Vissing, John

    2014-01-01

    OBJECTIVE: The 6-minute walk test is widely used to assess functional status in neurological disorders. However, the test is subject to great inter-test variability due to fluctuating motivation, fatigue and learning effects. We investigated whether inter-test variability of the 6MWT can be reduced...... cardiac arrhythmias, if they received drug treatment for hypertension or any other medical conditions that could interfere with the interpretation of the heart rate and walking capability. All completed three 6-minute walk tests on three different test-days. Heart rate was measured continuously. RESULTS......: Successive standard 6-minute walk tests showed considerable learning effects between Tests 1 and 2 (4.9%; P = 0.026), and Tests 2 and 3 (4.5%; P = 0.020) in patients. The same was seen in controls between Tests 1 and 2 (8.1%; P = 0.039)). Heart rate correction abolished this learning effect. CONCLUSION...

  8. Quantum walks assisted by particle number fluctuations

    Science.gov (United States)

    Vargas-Hernandez, Rodrigo A.; v Krems, Roman

    2017-04-01

    We consider quantum walks of particles governed by lattice Hamiltonians with particle-number changing interactions. We show that such interactions, even if weak, accelerate quantum walks at short times due to Rabi oscillations between different particle number subspaces. We examine the dynamics of quantum walks governed by Hamiltonians arising in the context of D-wave quantum annealing experiments and experiments with excitations of ultracold molecules in optical lattices. The same Hamiltonians describe excitations in ensembles of highly magnetic atoms, such as Dy.

  9. Random walk statistics on fractal structures

    Science.gov (United States)

    Rammal, R.

    1984-09-01

    We consider some statistical properties of simple random walks on fractal structures viewed as networks of sites and bonds: range, renewal theory, mean first passage time, etc. Asymptotic behaviors are shown to be controlled by the fractal ( ¯d) and spectral ( ¯d) dimensionalities of the considered structure. A simple decimation procedure giving the value of ( ¯d) is outlined and illustrated in the case of the Sierpinski gaskets. Recent results for the trapping problem, the self-avoiding walk, and the true-self-avoiding walk are briefly reviewed. New numerical results for diffusion on percolation clusters are also presented.

  10. Further results on self-avoiding walks

    Science.gov (United States)

    Temperley, H. N. V.

    1994-05-01

    A Gaussian model of self-avoiding walks is studied. Not only is any cluster integral exactly evaluable, but whole sub-series can be evaluated exactly in terms of associated Riemann zeta functions. The results are compared with information recently obtained on self-avoiding walks on the plane square and simple cubic lattices and, as expected, are very similar. Use is made of the author's recent result that the reciprocal of the walks generating function is the generating function for irreducible cluster-sums. This is split into sub-series all of which have the same radius of convergence, and the significance of this is discussed.

  11. Walking reduces the gap between encoding and sensorimotor alignment effects in spatial updating of described environments.

    Science.gov (United States)

    Santoro, Ilaria; Murgia, Mauro; Sors, Fabrizio; Agostini, Tiziano

    2017-04-01

    Spatial updating allows people to keep track of the self-to-object relations during movement. Previous studies demonstrated that physical movement enhanced spatial updating in remote environments, but failed to find the same effect in described environments. However, these studies mainly considered rotation as a physical movement, without examining other types of movement, such as walking. We investigated how walking affects spatial updating within described environments. Using the judgement of relative directions task, we compared the effects of imagination of rotation, physical rotation, and walking on spatial updating. Spatial updating was evaluated in terms of accuracy and response times in different perspectives, and by calculating two indexes, namely the encoding and sensorimotor alignment effects. As regards response times, we found that in the imagination of rotation and physical rotation conditions the encoding alignment effect was higher than the sensorimotor alignment effect, while in the walking condition this gap disappeared. We interpreted these results in terms of an enhanced link between allocentric and sensorimotor representations, due to the information acquired through walking.

  12. Health benefits of increased walking for sedentary, generally healthy older adults: using longitudinal data to approximate an intervention trial.

    Science.gov (United States)

    Diehr, Paula; Hirsch, Calvin

    2010-09-01

    Older adults are often advised to walk more, but randomized trials have not conclusively established the benefits of walking in this age group. Typical analyses based on observational data may have biased results. Here, we propose a "limited-bias," more interpretable estimate of the health benefits to sedentary healthy older adults of walking more, using longitudinal data from the Cardiovascular Health Study. The number of city blocks walked per week, collected annually, was classified as sedentary (or=28). Analysis was restricted to persons sedentary and healthy in the first 2 years. In Year 3, some became more active (the treatment groups). Self-rated health at Year 5 (follow-up) was regressed on walking at Year 3, with additional covariates from Year 2, when all were sedentary. At follow-up, 83.5% of those active at baseline had excellent, very good, or good self-rated health, as compared with 63.9% of the sedentary, an apparent benefit of 19.6 percentage points. After covariate adjustment, the limited-bias estimate of the benefit was 11.2 percentage points (95% confidence interval 3.7-18.6). Ten different outcome measures showed a benefit, ranging from 5 to 11 percentage points. Estimates from other study designs were smaller, less interpretable, and potentially more biased. In longitudinal studies where walking and health are ascertained at every wave, limited-bias estimates can provide better estimates of the benefits of walking. A surprisingly small increase in walking was associated with meaningful health benefits.

  13. How do environmental factors influence walking in groups? A walk-along study.

    Science.gov (United States)

    Kassavou, Aikaterini; French, David P; Chamberlain, Kerry

    2015-10-01

    Insufficient attention has been given to the influence of context on health-related behaviour change. This article reports on walk-along interviews conducted with 10 leaders of walking groups while leading their groups to investigate the influence of contextual factors on walking behaviours in groups. Data analysis used ideas from thematic analysis and grounded theory, approaching the data inductively. We identified that characteristics of place influenced the type of walking that people do in groups and the processes used by walkers to make sense of their behaviours in the places they walk. This research provides insight into how place influences walking in groups. It also suggests recommendations for co-ordinators and policymakers that could be used to facilitate behaviour change, when designing interventions targeting public health within the community. © The Author(s) 2013.

  14. Design of a walking robot

    Science.gov (United States)

    Whittaker, William; Dowling, Kevin

    1994-01-01

    Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.

  15. How might we increase physical activity through dog walking?: A comprehensive review of dog walking correlates.

    Science.gov (United States)

    Westgarth, Carri; Christley, Robert M; Christian, Hayley E

    2014-08-20

    Physical inactivity and sedentary behaviour are major threats to population health. A considerable proportion of people own dogs, and there is good evidence that dog ownership is associated with higher levels of physical activity. However not all owners walk their dogs regularly. This paper comprehensively reviews the evidence for correlates of dog walking so that effective interventions may be designed to increase the physical activity of dog owners. Published findings from 1990-2012 in both the human and veterinary literature were collated and reviewed for evidence of factors associated with objective and self-reported measures of dog walking behaviour, or reported perceptions about dog walking. Study designs included cross-sectional observational, trials and qualitative interviews. There is good evidence that the strength of the dog-owner relationship, through a sense of obligation to walk the dog, and the perceived support and motivation a dog provides for walking, is strongly associated with increased walking. The perceived exercise requirements of the dog may also be a modifiable point for intervention. In addition, access to suitable walking areas with dog supportive features that fulfil dog needs such as off-leash exercise, and that also encourage human social interaction, may be incentivising. Current evidence suggests that dog walking may be most effectively encouraged through targeting the dog-owner relationship and by providing dog-supportive physical environments. More research is required to investigate the influence of individual owner and dog factors on 'intention' to walk the dog as well as the influence of human social interaction whilst walking a dog. The effects of policy and cultural practices relating to dog ownership and walking should also be investigated. Future studies must be of a higher quality methodological design, including accounting for the effects of confounding between variables, and longitudinal designs and testing of

  16. 'Join the walk?': Short- and long-term effects of a walking program for mentally disordered

    OpenAIRE

    Vanroy, Jari; Seghers, Jan; Bogaerts, An; Boen, Filip

    2015-01-01

    Background & objectives: Physical activity (PA) has potentially beneficial effects on several domains of mental health. Furthermore, walking has been proposed as a promising strategy for improving the level of PA and mental health. A previous study by Pelssers and colleagues (2013) provided evidence for the short-term effectiveness of a structured walking program (‘Every Step Counts’) in a population of healthy elderly. This walking intervention program was embedded within a socio-cultura...

  17. Parent Safety Perceptions of Child Walking Routes.

    Science.gov (United States)

    Evers, Cody; Boles, Shawn; Johnson-Shelton, Deb; Schlossberg, Marc; Richey, David

    2014-06-01

    Walking rates to school remain low for U.S. children in large part due to parent concern for child safety. Little research has investigated the specific features of streets and intersection networks that parents associate with safe walking networks for children. To investigate which aspects of the child walking environment lead to parental concern, parent volunteers conducted an audit of streets leading to seven elementary schools in a suburban school district. Parents were most likely to feel concern about streets that lacked sidewalks or had sidewalks with obstructions. Wheelchair-accessible routes were seen as appropriate for walking children. Parents expressed concern over safety at intersections, particularly those involving large streets; traffic controls did not mollify their concern.

  18. Walking ability in patients with glioblastoma

    DEFF Research Database (Denmark)

    Liljehult, Monique Mesot; Buus, Lise; Mesot Liljehult, Jacob

    2017-01-01

    ability and 1 year mortality. Data were gathered from prospective recordings in a brain cancer database supplemented by retrospective review of electronic patient records. We included 109 patients with glioblastoma, 47 women and 62 men with mean age 65 years. At admission 84 patients were tested with Berg......Primary brain tumors frequently cause considerable functional impairments and the survival time when diagnosed with glioblastoma is 14.6 months. The aim of this study was to examine if baseline postural control and walking ability in patients with glioblastoma could predict long term walking...... higher in patients who lost their ability to walk within 4-8 months of the first admission. This study showed that Berg Balance Scale has some ability to predict the loss of walking ability 4-8 months after admission. This could be an important indicator pin pointing patients most in need of more...

  19. The random walk model of intrafraction movement

    International Nuclear Information System (INIS)

    Ballhausen, H; Reiner, M; Kantz, S; Belka, C; Söhn, M

    2013-01-01

    The purpose of this paper is to understand intrafraction movement as a stochastic process driven by random external forces. The hypothetically proposed three-dimensional random walk model has significant impact on optimal PTV margins and offers a quantitatively correct explanation of experimental findings. Properties of the random walk are calculated from first principles, in particular fraction-average population density distributions for displacements along the principal axes. When substituted into the established optimal margin recipes these fraction-average distributions yield safety margins about 30% smaller as compared to the suggested values from end-of-fraction Gaussian fits. Stylized facts of a random walk are identified in clinical data, such as the increase of the standard deviation of displacements with the square root of time. Least squares errors in the comparison to experimental results are reduced by about 50% when accounting for non-Gaussian corrections from the random walk model. (paper)

  20. The random walk model of intrafraction movement.

    Science.gov (United States)

    Ballhausen, H; Reiner, M; Kantz, S; Belka, C; Söhn, M

    2013-04-07

    The purpose of this paper is to understand intrafraction movement as a stochastic process driven by random external forces. The hypothetically proposed three-dimensional random walk model has significant impact on optimal PTV margins and offers a quantitatively correct explanation of experimental findings. Properties of the random walk are calculated from first principles, in particular fraction-average population density distributions for displacements along the principal axes. When substituted into the established optimal margin recipes these fraction-average distributions yield safety margins about 30% smaller as compared to the suggested values from end-of-fraction gaussian fits. Stylized facts of a random walk are identified in clinical data, such as the increase of the standard deviation of displacements with the square root of time. Least squares errors in the comparison to experimental results are reduced by about 50% when accounting for non-gaussian corrections from the random walk model.

  1. Personal literary interpretation

    Directory of Open Access Journals (Sweden)

    Michał Januszkiewicz

    2015-11-01

    Full Text Available The article titled “Personal literary interpretation” deals with problems which have usually been marginalized in literary studies, but which seem to be very important in the context of the humanities, as broadly defined. The author of this article intends to rethink the problem of literary studies not in objective, but in personal terms. This is why the author wants to talk about what he calls personal literary interpretation, which has nothing to do with subjective or irrational thinking, but which is rather grounded in the hermeneutical rule that says that one must believe in order tounderstand a text or the other (where ‘believe’ also means: ‘to love’, ‘engage’, and ‘be open’. The article presents different determinants of this attitude, ranging from Dilthey to Heidegger and Gadamer. Finally, the author subscribes to the theory of personal interpretation, which is always dialogical.

  2. Interpretation and clinical applications

    International Nuclear Information System (INIS)

    Higgins, C.B.

    1987-01-01

    This chapter discusses the factors to be kept in mind during routine interpretation of MR images. This includes the factors that determine contrast on standard spin-echo images and some distinguishing features between true lesions and artifactually simulated lesions. This chapter also indicates the standard protocols for MRI of various portions of the body. Finally, the current indications for MRI of various portions of the body are suggested; however, it is recognized that the indications for MRI are rapidly increasing and consequently, at the time of publication of this chapter, it is likely that many more applications will have become evident. Interpretation of magnetic resonance (MR) images requires consideration of anatomy and tissue characteristics and extraction of artifacts resulting from motion and other factors

  3. Interpretation as doing

    DEFF Research Database (Denmark)

    Majgaard Krarup, Jonna

    2008-01-01

    The intent of the paper is to address and discuss relationships between the aesthetic perception and interpretation of contemporary landscape architecture. I will try to do this by setting up a cross-disciplinary perspective that looks into themes from the contemporary art scene and aesthetic...... theories, and relate them to observations in contemporary landscape architecture. It is my premise that investigating the relationship between modes of aesthetic perception and examples in contemporary art, and landscape architecture, will enable us to better understand characteristics of a contemporary...... concept of landscape and design in landscape architecture, and hereby address the question of how interpretation might be processed. It is also my premise that a key point in this is the interplay between different sensory experiences of both material and non-material aspects...

  4. Interpretation of Internet technology

    DEFF Research Database (Denmark)

    Madsen, Charlotte Øland

    2001-01-01

    Research scope: The topic of the research project is to investigate how new internet technologies such as e-trade and customer relation marketing and management are implemented in Danish food processing companies. The aim is to use Weick's (1995) sensemaking concept to analyse the strategic...... processes leading to the use of internet marketing technologies and to investigate how these new technologies are interpreted into the organisation. Investigating the organisational socio-cognitive processes underlying the decision making processes will give further insight into the socio......-cognitive competencies of organisations (Rindova & Fombrunn, 1999). The aim is to contribute to the existing technological implementation theory complex by studying the relationships between the elements of the socio-cognitive processes and the resulting interpretations and actions when new technologies are implemented...

  5. Interpretations of interpretivism

    OpenAIRE

    Gerring, John

    2003-01-01

    What is interpretivism? As is common with broad methodological debates, much hinges on matters of definition. Interpretivism might be defined residually — as non-positivism. However, this scarcely clarifies the matter, as noted by Robert Adcock and David Dessler in their contributions to this symposium. We might start with David Laitin’s suggestion that interpretivism refers to interpretation or clarification— rendering the ambiguous into a clearer form. This is true enough, so far as it ...

  6. A Narrative Interpretive Perspective

    OpenAIRE

    Adorisio, Anna Linda Musacchio

    2015-01-01

    In this paper I will discuss the possibility offered by the “linguistic turn” for narrative research in the realm of financial communication. I will propose three categories by which a narrative interpretive approach can be applied to financial communication: narrative-as-artifacts, narrative-as-practice and narrative-as-method. Such a constitutive communication approach challenges a mechanistic and functionalist view of communication as a tool to represent social realities in ...

  7. Interpretative phenomenological analysis

    OpenAIRE

    Eatough, Virginia; Smith, Jonathan A.

    2017-01-01

    The Second Edition of The SAGE Handbook of Qualitative Research in Psychology provides comprehensive coverage of the qualitative methods, strategies, and research issues in psychology.\\ud \\ud Qualitative research in psychology has been transformed since the first edition's publication. Responding to this evolving field, existing chapters have been updated while three new chapters have been added on Thematic Analysis, Interpretation, and Netnography. With a focus on methodological progress thr...

  8. Does getting a dog increase recreational walking?

    Directory of Open Access Journals (Sweden)

    Knuiman Matthew W

    2008-03-01

    Full Text Available Abstract Background This study examines changes in socio-demographic, environmental and intrapersonal factors associated with dog acquisition in non-dog owners at baseline to 12-months follow-up and the effect of dog acquisition on minutes per week of recreational walking. Methods RESIDE study participants completed self-administered questionnaires (baseline and 12-months follow-up measuring physical activity, dog ownership, dog walking behavior as well as environmental, intrapersonal and socio-demographic factors. Analysis was restricted to 'Continuing non-owners' (i.e., non-owners at both baseline and follow-up; n = 681 and 'New dog owners' (i.e., non-owners who acquired a dog by follow-up; n = 92. Results Overall, 12% of baseline non-owners had acquired a dog at follow-up. Dog acquisition was associated with working and having children at home. Those who changed from single to couple marital status were also more likely to acquire a dog. The increase in minutes of walking for recreation within the neighborhood from baseline to follow-up was 48 minutes/week for new dog owners compared with 12 minutes/week for continuing non-owners (p p p > 0.05 after further adjustment for change in baseline to follow-up variables. Increase in intention to walk was the main factor contributing to attenuation of the effect of dog acquisition on recreational walking. Conclusion This study used a large representative sample of non-owners to examine the relationship between dog acquisition and recreational walking and provides evidence to suggest that dog acquisition leads to an increase in walking. The most likely mechanism through which dog acquisition facilitates increased physical activity is through behavioral intention via the dog's positive effect on owner's cognitive beliefs about walking, and through the provision of motivation and social support for walking. The results suggest that behavioral intention mediates the relationship between dog acquisition

  9. The Age of Interpretation

    Directory of Open Access Journals (Sweden)

    Gianni Vattimo

    2013-01-01

    Full Text Available Gianni Vattimo, who is both a Catholic and a frequent critic of the Church, explores the surprising congruence between Christianity and hermeneutics in light of the dissolution of metaphysical truth. As in hermeneutics, Vatimo claims, interpretation is central to Christianity. Influenced by hermeneutics and borrowing largely from the Nietzschean and Heideggerian heritage, the Italian philosopher, who has been instrumental in promoting a nihilistic approach to Christianity, draws here on Nietzsche’s writings on nihilism, which is not to be understood in a purely negative sense. Vattimo suggests that nihilism not only expands the Christian message of charity, but also transforms it into its endless human potential. In “The Age of Interpretation,” the author shows that hermeneutical radicalism “reduces all reality to message,” so that the opposition between facts and norms turns out to be misguided, for both are governed by the interpretative paradigms through which someone (always a concrete, historically situated someone makes sense of them. Vattimo rejects some of the deplorable political consequences of hermeneutics and claims that traditional hermeneutics is in collusion with various political-ideological neutralizations.

  10. Effects of walking trainings on walking function among stroke survivors: a systematic review.

    Science.gov (United States)

    Ilunga Tshiswaka, Daudet; Bennett, Crystal; Franklin, Cheyanne

    2018-03-01

    Physical function is often compromised as a result of stroke event. Although interventions propose different strategies that seek to improve stroke survivors' physical function, a need remains to evaluate walking training studies aimed at improving such physical function. The aim of this review was to assess the available literature that highlights the impact of walking training on enhancing walking for stroke survivors. We performed a systematic literature review of online databases - Google Scholar, PubMed, CINHAL, Cochrane Library, Scopus, and EBSCO - with the following inclusion criteria: manuscript published from 2005 to 2016, written in English, with treatment and control groups, for walking training studies aimed at improving physical function among stroke survivors. Findings indicated that walking speed, walking distance, and gait speed were the most used outcome variables for measuring improved physical function among stroke survivors. Importantly, proposed interventions involved either overground or treadmill walking trainings, if not both. Preserved locomotor improvements were not noted in all interventions at follow-up. Some interventions that used walking treadmill training augmented by auditory stimulations reported significant improvements in physical function compared with overground walking training augmented by auditory stimulations. The imperative to improve physical function among stroke survivors with physical impairment is paramount, as it allows survivors to be socially, emotionally, and physically more independent. In general, we note an insufficiency of research on the interaction between physical function and socialization among stroke survivors.

  11. The WalkTrainer--a new generation of walking reeducation device combining orthoses and muscle stimulation.

    Science.gov (United States)

    Stauffer, Y; Allemand, Y; Bouri, M; Fournier, J; Clavel, R; Metrailler, P; Brodard, R; Reynard, F

    2009-02-01

    This paper presents a novel reeducation device for paraplegics that combines hybrid orthoses and closed-loop electrical muscle stimulation. Based on the so called Cyberthosis concept, the WalkTrainer enables an active muscular participation of the subject in the walking reeducation process by the mean of closed-loop muscle stimulation. The WalkTrainer is also equipped with a leg and pelvic orthosis, an active bodyweight support, and motorized wheels to allow true over ground deambulation. This paper will focus on the development of the WalkTrainer, the presentation of the control strategies, and also give some preliminary results of the first clinical trials.

  12. Reliability and Validity of the 50-ft Walk Test for Idiopathic Toe Walking.

    Science.gov (United States)

    Christensen, Catie; Haddad, Amanda; Maus, Elizabeth

    2017-07-01

    To evaluate interrater reliability and concurrent validity of the 50-ft walk test (FWT) for children with idiopathic toe walking (ITW). Thirty children, 6 to 13 years old, with ITW participated. During the 50-FWT, an accelerometer counted total steps. A physical therapist counted the number of toe-walking steps. The number of toe-walking steps was divided by the total steps to calculate a toe-walking percentage. Interrater reliability was assessed by correlating the toe-walking percentage obtained by 2 raters using an intraclass correlation coefficient. Concurrent validity was evaluated by correlating the toe-walking percentage calculated by the GAITRite and therapist using a Spearman ρ. There was excellent interrater reliability and concurrent validity. Experience level did not impact the therapist's ability to identify a toe-walking step. The 50-FWT demonstrated excellent interrater reliability and concurrent validity. It can be used to obtain a percentage of toe walking in children 6-13 years of age with ITW.

  13. Two- and 6-minute walk tests assess walking capability equally in neuromuscular diseases.

    Science.gov (United States)

    Andersen, Linda Kahr; Knak, Kirsten Lykke; Witting, Nanna; Vissing, John

    2016-02-02

    This methodologic study investigates if the 2-minute walk test (2MWT) can be a valid alternative to the 6-minute walk test (6MWT) to describe walking capability in patients with neuromuscular diseases. Patients (n = 115) with different neuromuscular diseases were invited to participate on 2 test days, each consisting of 1 2MWT and 1 6MWT separated by a minimum 30-minute period of rest. The order of the walk tests was randomly assigned via sealed envelopes. A group of 38 healthy controls completed 1 6MWT. The mean walking distance for the 2MWT was 142.8 meters and for the 6MWT 405.3 meters. The distance walked in the 2MWT was highly correlated to the distance walked in the 6MWT (r = 0.99, p walking speed from the first to last minute in the 6MWT, both among patients and healthy controls, which was not evident in the 2MWT. Results were consistent across diagnoses and levels of disease severity. The 2MWT is a potential alternative to the 6MWT to describe walking capability among patients with neuromuscular diseases during clinical trials. © 2016 American Academy of Neurology.

  14. The 2-min walk test is sufficient for evaluating walking abilities in sporadic inclusion body myositis.

    Science.gov (United States)

    Alfano, L N; Lowes, L P; Dvorchik, I; Yin, H; Maus, E G; Flanigan, K M; Mendell, J R

    2014-03-01

    Sporadic inclusion body myositis causes progressive functional loss due to declining muscle strength. Although the underlying cause is unknown, clinical trials are underway to improve strength and function. Selection of appropriate outcome measures is critical for the success of these trials. The 6-min walk test has been the de facto standard for assessing function in neuromuscular disease; however, the optimal walking test has not been determined in this disease. In this study, 67 individuals with sporadic inclusion body myositis completed a battery of quantitative strength and functional tests including timed walking tests, patient-reported outcomes, and other tasks. The 2-min and 6-min walk tests are highly correlated to each other (r=0.97, pwalk test, but 7% of subjects were unable to walk the full 6-min of the 6-min walk test due to fatigue. The 2-min walk test demonstrates similar correlation to all outcomes compared to the 6-min walk test, is less fatiguing and better tolerated. Results suggest that the 2-min walk test is a better alternative to tests of longer duration. Further research is needed to determine longitudinal changes on this outcome. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Factors associated with daily walking of dogs

    OpenAIRE

    Westgarth, Carri; Christian, Hayley E.; Christley, Robert M.

    2015-01-01

    Background Regular physical activity is beneficial to the health of both people and animals. The role of regular exercise undertaken together, such as dog walking, is a public health interest of mutual benefit. Exploration of barriers and incentives to regular dog walking by owners is now required so that effective interventions to promote it can be designed. This study explored a well-characterised cross-sectional dataset of 276 dogs and owners from Cheshire, UK, for evidence of factors asso...

  16. Factors associated with daily walking of dogs.

    Science.gov (United States)

    Westgarth, Carri; Christian, Hayley E; Christley, Robert M

    2015-05-19

    Regular physical activity is beneficial to the health of both people and animals. The role of regular exercise undertaken together, such as dog walking, is a public health interest of mutual benefit. Exploration of barriers and incentives to regular dog walking by owners is now required so that effective interventions to promote it can be designed. This study explored a well-characterised cross-sectional dataset of 276 dogs and owners from Cheshire, UK, for evidence of factors associated with the dog being walked once or more per day. Factors independently associated with daily walking included: number of dogs owned (multiple (vs. single) dogs negatively associated); size (medium and possibly large dogs (vs. small) positively associated); and number of people in the household (more people negatively associated). Furthermore, a number of factors related to the dog-owner relationship and the dog's behaviour were associated with daily walking, including: having acquired the dog for a hobby (positively associated); dog lying on furniture (positively associated); dog lying on laps (negatively associated); growling at household members (negatively associated); and playing chase games with the dog (negatively associated). These findings are consistent with the hypothesis that the strength and nature of the human-dog relationship incentivises dog walking, and that behavioural and demographic factors may affect dog walking via this mechanism. Future studies need to investigate how dog demographic and behavioural factors, plus owner behavioural factors and perceptions of the dog, influence the dog-human relationship in respect to the perceived support and motivation a dog can provide for walking.

  17. More Adults Are Walking PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2012-07-31

    This 60 second PSA is based on the August 2012 CDC Vital Signs report. While more adults are walking, only half get the recommended amount of physical activity. Listen to learn how communities, employers, and individuals may help increase walking.  Created: 7/31/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 8/7/2012.

  18. The Walking Egg non-profit organisation

    OpenAIRE

    Dhont, N.

    2011-01-01

    The Walking Egg non-profit organisation (npo) was founded in 2010 by scientists and an artist to realise the Arusha Project which strives to implement accessible infertility programmes in resource-poor countries. Right from the start The Walking Egg has opted for a multidisciplinary and global approach towards the problem of infertility and in cooperation with the Special Task Force (STF) on “Developing countries and infertility” of the European Society of Human reproduction and Embryology (E...

  19. Locomotor sequence learning in visually guided walking.

    Science.gov (United States)

    Choi, Julia T; Jensen, Peter; Nielsen, Jens Bo

    2016-04-01

    Voluntary limb modifications must be integrated with basic walking patterns during visually guided walking. In this study we tested whether voluntary gait modifications can become more automatic with practice. We challenged walking control by presenting visual stepping targets that instructed subjects to modify step length from one trial to the next. Our sequence learning paradigm is derived from the serial reaction-time (SRT) task that has been used in upper limb studies. Both random and ordered sequences of step lengths were used to measure sequence-specific and sequence-nonspecific learning during walking. In addition, we determined how age (i.e., healthy young adults vs. children) and biomechanical factors (i.e., walking speed) affected the rate and magnitude of locomotor sequence learning. The results showed that healthy young adults (age 24 ± 5 yr,n= 20) could learn a specific sequence of step lengths over 300 training steps. Younger children (age 6-10 yr,n= 8) had lower baseline performance, but their magnitude and rate of sequence learning were the same compared with those of older children (11-16 yr,n= 10) and healthy adults. In addition, learning capacity may be more limited at faster walking speeds. To our knowledge, this is the first study to demonstrate that spatial sequence learning can be integrated with a highly automatic task such as walking. These findings suggest that adults and children use implicit knowledge about the sequence to plan and execute leg movement during visually guided walking. Copyright © 2016 the American Physiological Society.

  20. A random walk down Main Street

    OpenAIRE

    David Matthew Levinson

    2016-01-01

    US suburbs have often been characterized by their relatively low walk accessibility compared to more urban environments, and US urban environments have been char- acterized by low walk accessibility compared to cities in other countries. Lower overall density in the suburbs implies that activities, if spread out, would have a greater distance between them. But why should activities be spread out instead of developed contiguously? This brief research note builds a positive model for the emerge...

  1. A Walk in the Semantic Park

    DEFF Research Database (Denmark)

    Danvy, Olivier; Johannsen, Jacob; Zerny, Ian

    2011-01-01

    To celebrate the 20th anniversary of PEPM, we are inviting you to a walk in the semantic park and to inter-derive reduction-based and reduction-free negational normalization functions.......To celebrate the 20th anniversary of PEPM, we are inviting you to a walk in the semantic park and to inter-derive reduction-based and reduction-free negational normalization functions....

  2. Many random walks are faster than one

    Czech Academy of Sciences Publication Activity Database

    Alon, N.; Avin, Ch.; Koucký, Michal; Kozma, G.; Lotker, Z.; Tuttle, M.R.

    2011-01-01

    Roč. 20, č. 4 (2011), s. 481-502 ISSN 0963-5483 R&D Projects: GA ČR GP201/07/P276; GA ČR GA201/05/0124 Institutional research plan: CEZ:AV0Z10190503 Keywords : multiple random walks * parallel random walks Subject RIV: BA - General Mathematics Impact factor: 0.778, year: 2011 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8280727

  3. Go Naked: Diapers Affect Infant Walking

    OpenAIRE

    Cole, Whitney G.; Lingeman, Jesse M.; Adolph, Karen E.

    2012-01-01

    In light of cross-cultural and experimental research highlighting effects of childrearing practices on infant motor skill, we asked whether wearing diapers, a seemingly innocuous childrearing practice, affects infant walking. Diapers introduce bulk between the legs, potentially exacerbating infants’ poor balance and wide stance. We show that walking is adversely affected by old-fashioned cloth diapers, and that even modern disposable diapers—habitually worn by most infants in the sample—incur...

  4. Nordic Walking Practice Might Improve Plantar Pressure Distribution

    Science.gov (United States)

    Perez-Soriano, Pedro; Llana-Belloch, Salvador; Martinez-Nova, Alfonso; Morey-Klapsing, G.; Encarnacion-Martinez, Alberto

    2011-01-01

    Nordic walking (NW), characterized by the use of two walking poles, is becoming increasingly popular (Morgulec-Adamowicz, Marszalek, & Jagustyn, 2011). We studied walking pressure patterns of 20 experienced and 30 beginner Nordic walkers. Plantar pressures from nine foot zones were measured during trials performed at two walking speeds (preferred…

  5. Physical Strain: A New Perspective on Walking in Cerebral Palsy

    NARCIS (Netherlands)

    Balemans, Astrid C.; Bolster, Eline A.; Brehm, Merel-Anne; Dallmeijer, Annet J.

    2017-01-01

    Objectives: To describe (1) physical strain of walking, (2) the proportion of participants walking above the anaerobic threshold, and (3) 4 phenotypes of physical strain of walking on the basis of deviations in aerobic capacity and walking energy cost (EC) in children and adolescents with cerebral

  6. Limit Theorems For the Grover Walk Without Memory

    OpenAIRE

    Ampadu, Clement

    2011-01-01

    We consider the Grover walk as a 4-state quantum walk without memory in one dimension. The walker in our 4-state quantum walk moves to the left or right. We compute the stationary distribution of the walk, in addition, we obtain the weak limit theorem

  7. The effect of walking speed on hamstrings length and lengthening velocity in children with spastic cerebral palsy

    NARCIS (Netherlands)

    Krogt, van der M.M.; Doorenbosch, C.A.M.; Harlaar, J.

    2009-01-01

    0.001). These data are important as a reference for valid interpretation of hamstrings length and velocity data in gait analyses at different walking speeds. The results indicate that the presence of spasticity is associated with reduced hamstrings length and lengthening velocity during gait, even

  8. Walking behaviours from the 1965–2003 American Heritage Time Use Study (AHTUS

    Directory of Open Access Journals (Sweden)

    Merom Dafna

    2007-09-01

    various survey administrations preclude stringent interpretation of these trends in walking behaviours and the use of conventional application of inferential statistics to evaluate significance of time trends. Although the AHTUS offers the most comprehensive attempt at harmonization yet undertaken with these individual time-use surveys, we found that any noted cross-time changes in walking and physical activity behaviour are not easily interpreted in terms of conventional epidemiological approaches and could be true changes, artefact related to instrument and method changes, or both. Public health utilization of the AHTUS, could be enhanced with greater attention to methodological issues known to influence estimation of physical activity behaviour in population. This could be achieved with cross-disciplinary collaboration between groups of experts in the various stages of these surveys.

  9. Different microscopic interpretations of the reaction-telegrapher equation

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Daniel; Mendez, Vicenc [Grup de Fisica EstadIstica, Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Barcelona) (Spain)

    2009-02-20

    In this paper we provide some new insights into the microscopic interpretation of the telegrapher's and the reaction-telegrapher equations. We use the framework of continuous-time random walks to derive the telegrapher's equation from two different perspectives reported before: the kinetic derivation (KD) and the delayed random-walk derivation (DRWD). We analyze the similarities and the differences between both derivations, paying special attention to the case when a reaction process is also present in the system. As a result, we are able to show that the equivalence between the KD and the DRWD can break down when transport and reaction are coupled processes. Also, this analysis allows us to elaborate on the specific role of relaxation effects in reaction-diffusion processes.

  10. Understanding Walking Behavior: Its Benefits and Barriers

    Directory of Open Access Journals (Sweden)

    Fatmawati

    2016-12-01

    Full Text Available Health survey demonstrates that 5.3 million people each year experienced a premature death due to physical inactivity (Lee et al., 2012. Data from Department of Health (2004 revealed that in the United Kingdom more than 60% of adult males and 75% of adult females did not perform enough physical activity. Hence, to minimize this problem, currently, health practitioners are trying to encourage people to be more physically active, especially by promoting several types of exercise, including walking (Marshall et al., 2009; Hallal et al., 2012. Regular walking is one of the essential predictors for long-term physical and mental health benefit. Some recent studies mention that there are lots of advantages if adults can maintain their regular walking (Gunnell, Knuiman, Divitini, & Cormie, 2014; Morgan, Tobar, & Synder, 2010; Roe & Aspinall, 2011; Shiue, 2015; Nagai et al., 2011. Regular walking minimum 10,000 steps each day can burn as much as 400 calories so that it may help overweight or obesity people to reduce their weight (NHS, 2014. However, most of the people perceive walking as one form of transport rather than exercise; therefore, this reason discourages them to walk sufficiently for healthy life purpose (Darker et al., 2007.

  11. Tempered Lévy walk of charged particles in turbulent magnetic field

    International Nuclear Information System (INIS)

    Sibatov, R T; Uchaikin, V V; Byzykchi, A N

    2017-01-01

    Recently, various diffusion regimes of ions and electrons in interplanetary magnetic field have been recognized from the data collected by different spacecrafts. Particularly for protons, superdiffusion and normal diffusion parallel to the mean magnetic field were declared, simulation also predicts transient superdiffusive behavior. We interpret parallel motion in terms of the one-dimensional tempered Lévy walk process and show that this representation is consistent with the experimental and simulated results. (paper)

  12. On the genealogy of branching random walks and of directed polymers

    Science.gov (United States)

    Derrida, Bernard; Mottishaw, Peter

    2016-08-01

    It is well known that the mean-field theory of directed polymers in a random medium exhibits replica symmetry breaking with a distribution of overlaps which consists of two delta functions. Here we show that the leading finite-size correction to this distribution of overlaps has a universal character which can be computed explicitly. Our results can also be interpreted as genealogical properties of branching Brownian motion or of branching random walks.

  13. Aging Renewal Theory and Application to Random Walks

    Directory of Open Access Journals (Sweden)

    Johannes H. P. Schulz

    2014-02-01

    Full Text Available We discuss a renewal process in which successive events are separated by scale-free waiting time periods. Among other ubiquitous long-time properties, this process exhibits aging: events counted initially in a time interval [0,t] statistically strongly differ from those observed at later times [t_{a},t_{a}+t]. The versatility of renewal theory is owed to its abstract formulation. Renewals can be interpreted as steps of a random walk, switching events in two-state models, domain crossings of a random motion, etc. In complex, disordered media, processes with scale-free waiting times play a particularly prominent role. We set up a unified analytical foundation for such anomalous dynamics by discussing in detail the distribution of the aging renewal process. We analyze its half-discrete, half-continuous nature and study its aging time evolution. These results are readily used to discuss a scale-free anomalous diffusion process, the continuous-time random walk. By this, we not only shed light on the profound origins of its characteristic features, such as weak ergodicity breaking, along the way, we also add an extended discussion on aging effects. In particular, we find that the aging behavior of time and ensemble averages is conceptually very distinct, but their time scaling is identical at high ages. Finally, we show how more complex motion models are readily constructed on the basis of aging renewal dynamics.

  14. Video interpretations in Danish hospitals

    DEFF Research Database (Denmark)

    Søbjerg, Lene Mosegaard; Noesgaard, Susanne; Henriksen, Jan Erik

    2013-01-01

    This article presents a study of an RCT comparing video interpretation with in-person interpretation at the Endocrinology Ward at Odense University Hospital.......This article presents a study of an RCT comparing video interpretation with in-person interpretation at the Endocrinology Ward at Odense University Hospital....

  15. Open quantum random walk in terms of quantum Bernoulli noise

    Science.gov (United States)

    Wang, Caishi; Wang, Ce; Ren, Suling; Tang, Yuling

    2018-03-01

    In this paper, we introduce an open quantum random walk, which we call the QBN-based open walk, by means of quantum Bernoulli noise, and study its properties from a random walk point of view. We prove that, with the localized ground state as its initial state, the QBN-based open walk has the same limit probability distribution as the classical random walk. We also show that the probability distributions of the QBN-based open walk include those of the unitary quantum walk recently introduced by Wang and Ye (Quantum Inf Process 15:1897-1908, 2016) as a special case.

  16. Design with the feet: walking methods and participatory design

    DEFF Research Database (Denmark)

    Kanstrup, Anne Marie; Bertelsen, Pernille; Madsen, Jacob Østergaard

    2014-01-01

    This paper presents an analysis of walking methods and their relation to participatory design (PD). The paper includes a study of walking methods found in the literature and an empirical study of transect walks in a PD project. From this analysis, we identify central attributes of, and challenges...... to, PD walks. Walking with people in the context of design is a natural activity for the participatory designer, who acknowledges the importance of immersion and relationships in design. However, the various intentions of walking approaches indicate an underacknowledged awareness of walking methods...

  17. Random Walk Quantum Clustering Algorithm Based on Space

    Science.gov (United States)

    Xiao, Shufen; Dong, Yumin; Ma, Hongyang

    2018-01-01

    In the random quantum walk, which is a quantum simulation of the classical walk, data points interacted when selecting the appropriate walk strategy by taking advantage of quantum-entanglement features; thus, the results obtained when the quantum walk is used are different from those when the classical walk is adopted. A new quantum walk clustering algorithm based on space is proposed by applying the quantum walk to clustering analysis. In this algorithm, data points are viewed as walking participants, and similar data points are clustered using the walk function in the pay-off matrix according to a certain rule. The walk process is simplified by implementing a space-combining rule. The proposed algorithm is validated by a simulation test and is proved superior to existing clustering algorithms, namely, Kmeans, PCA + Kmeans, and LDA-Km. The effects of some of the parameters in the proposed algorithm on its performance are also analyzed and discussed. Specific suggestions are provided.

  18. Quantum walks and non-Abelian discrete gauge theory

    Science.gov (United States)

    Arnault, Pablo; Di Molfetta, Giuseppe; Brachet, Marc; Debbasch, Fabrice

    2016-07-01

    A family of discrete-time quantum walks (DTQWs) on the line with an exact discrete U(N ) gauge invariance is introduced. It is shown that the continuous limit of these DTQWs, when it exists, coincides with the dynamics of a Dirac fermion coupled to usual U(N ) gauge fields in two-dimensional spacetime. A discrete generalization of the usual U(N ) curvature is also constructed. An alternate interpretation of these results in terms of superimposed U(1 ) Maxwell fields and SU(N ) gauge fields is discussed in the Appendix. Numerical simulations are also presented, which explore the convergence of the DTQWs towards their continuous limit and which also compare the DTQWs with classical (i.e., nonquantum) motions in classical SU(2 ) fields. The results presented in this paper constitute a first step towards quantum simulations of generic Yang-Mills gauge theories through DTQWs.

  19. Subdiffusion in time-averaged, confined random walks.

    Science.gov (United States)

    Neusius, Thomas; Sokolov, Igor M; Smith, Jeremy C

    2009-07-01

    Certain techniques characterizing diffusive processes, such as single-particle tracking or molecular dynamics simulation, provide time averages rather than ensemble averages. Whereas the ensemble-averaged mean-squared displacement (MSD) of an unbounded continuous time random walk (CTRW) with a broad distribution of waiting times exhibits subdiffusion, the time-averaged MSD, delta2, does not. We demonstrate that, in contrast to the unbounded CTRW, in which delta2 is linear in the lag time Delta, the time-averaged MSD of the CTRW of a walker confined to a finite volume is sublinear in Delta, i.e., for long lag times delta2 approximately Delta1-alpha. The present results permit the application of CTRW to interpret time-averaged experimental quantities.

  20. Walking in postpoliomyelitis syndrome: The relationships between time-scored tests, walking in daily life and perceived mobility problems

    NARCIS (Netherlands)

    Horemans, Herwin L. D.; Bussmann, Johannes B. J.; Beelen, Anita; Stam, Henk J.; Nollet, Frans

    2005-01-01

    Objective: To compare walking test results with walking in daily life, and to investigate the relationships between walking tests, walking activity in daily life, and perceived mobility problems in patients with post-poliomyelitis syndrome. Subjects: Twenty-four ambulant patients with

  1. The Effects of Walking or Walking-with-Poles Training on Tissue Oxygenation in Patients with Peripheral Arterial Disease

    Directory of Open Access Journals (Sweden)

    Eileen G. Collins

    2012-01-01

    Full Text Available This randomized trial proposed to determine if there were differences in calf muscle StO2 parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program. Data were collected on 85 patients who were randomized to a traditional walking program ( or walking-with-poles program ( of exercise training. Patients walked for 3 times weekly for 12 weeks. Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests ( traditional walking and walking-with-poles. Using the near-infrared spectroscopy measures, StO2 was measured prior to, during, and after exercise. At baseline, calf muscle oxygenation decreased from % prior to the treadmill test to % at peak exercise. The time elapsed prior to reaching nadir StO2 values increased more in the traditional walking group when compared to the walking-with-poles group. Likewise, absolute walking time increased more in the traditional walking group than in the walking-with-poles group. Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program. In conclusion, the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD.

  2. Aerobic treadmill plus Bobath walking training improves walking in subacute stroke: a randomized controlled trial.

    Science.gov (United States)

    Eich, H-J; Mach, H; Werner, C; Hesse, S

    2004-09-01

    To evaluate the immediate and long-term effects of aerobic treadmill plus Bobath walking training in subacute stroke survivors compared with Bobath walking training alone. Randomized controlled trial. Rehabilitation unit. Fifty patients, first-time supratentorial stroke, stroke interval less than six weeks, Barthel Index (0-100) from 50 to 80, able to walk a minimum distance of 12 m with either intermittent help or stand-by while walking, cardiovascular stable, minimum 50 W in the bicycle ergometry, randomly allocated to two groups, A and B. Group A 30 min of treadmill training, harness secured and minimally supported according to patients' needs, and 30 min of physiotherapy, every workday for six weeks, speed and inclination of the treadmill were adjusted to achieve a heart rate of HR: (Hrmax-HRrest)*0.6+HRrest; in group B 60 min of daily physiotherapy for six weeks. Primary outcome variables were the absolute improvement of walking velocity (m/s) and capacity (m), secondary were gross motor function including walking ability (score out of 13) and walking quality (score out of 41), blindly assessed before and after the intervention, and at follow-up three months later. Patients tolerated the aerobic training well with no side-effects, significantly greater improvement of walking velocity and capacity both at study end (p =0.001 versus p =0.002) and at follow-up (p Bobath walking training in moderately affected stroke patients was better than Bobath walking training alone with respect to the improvement of walking velocity and capacity. The treatment approach is recommended in patients meeting the inclusion criteria. A multicentre trial should follow to strengthen the evidence.

  3. Changing interpretations of Plotinus

    DEFF Research Database (Denmark)

    Catana, Leo

    2013-01-01

    ’ writings relatively late, in the 18th and 19th centuries, and that it was primarily made possible by Brucker’s methodology for history of philosophy, dating from the 1740s, in which the concept system of philosophy was essential. It is observed that the concept was absent in Ficino’s commentary from the 15......th century, and that it remained absent in interpretative works produced between the 15th and 18th century. It is also argued that it is erroneous to assume that Plotinus presented a system of philosophy, or intended to do so — we do not find this concept in Plotinus’ writings, and his own statements...

  4. Analysis of coined quantum walks with renormalization

    Science.gov (United States)

    Boettcher, Stefan; Li, Shanshan

    2018-01-01

    We introduce a framework to analyze quantum algorithms with the renormalization group (RG). To this end, we present a detailed analysis of the real-space RG for discrete-time quantum walks on fractal networks and show how deep insights into the analytic structure as well as generic results about the long-time behavior can be extracted. The RG flow for such a walk on a dual Sierpinski gasket and a Migdal-Kadanoff hierarchical network is obtained explicitly from elementary algebraic manipulations, after transforming the unitary evolution equation into Laplace space. Unlike for classical random walks, we find that the long-time asymptotics for the quantum walk requires consideration of a diverging number of Laplace poles, which we demonstrate exactly for the closed-form solution available for the walk on a one-dimensional loop. In particular, we calculate the probability of the walk to overlap with its starting position, which oscillates with a period that scales as NdwQ/df with system size N . While the largest Jacobian eigenvalue λ1 of the RG flow merely reproduces the fractal dimension, df=log2λ1 , the asymptotic analysis shows that the second Jacobian eigenvalue λ2 becomes essential to determine the dimension of the quantum walk via dwQ=log2√{λ1λ2 } . We trace this fact to delicate cancellations caused by unitarity. We obtain identical relations for other networks, although the details of the RG analysis may exhibit surprisingly distinct features. Thus, our conclusions—which trivially reproduce those for regular lattices with translational invariance with df=d and dwQ=1 —appear to be quite general and likely apply to networks beyond those studied here.

  5. Walking on high heels changes muscle activity and the dynamics of human walking significantly

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Svendsen, Morten Bo Søndergaard; Nørreslet, Andreas

    2012-01-01

    digital video cameras operating at 50 frames/second. Both barefooted walking and walking on high-heeled shoes (heel height: 9 cm) were recorded. Net joint moments were calculated by 3D inverse dynamics. EMG was recorded from eight leg muscles. The knee extensor moment peak in the first half of the stance...

  6. Walking on fractals: diffusion and self-avoiding walks on percolation clusters

    International Nuclear Information System (INIS)

    Blavatska, V; Janke, W

    2009-01-01

    We consider random walks (RWs) and self-avoiding walks (SAWs) on disordered lattices directly at the percolation threshold. Applying numerical simulations, we study the scaling behavior of the models on the incipient percolation cluster in space dimensions d = 2, 3, 4. Our analysis yields estimates of universal exponents, governing the scaling laws for configurational properties of RWs and SAWs

  7. Does walking strategy in older people change as a function of walking distance?

    NARCIS (Netherlands)

    Najafi, Bijan; Helbostad, Jorunn L.; Moe-Nilssen, Rolf; Zijlstra, Wiebren; Aminian, Kamiar

    This study investigates whether the spatio-temporal parameters of gait in the elderly vary as a function of walking distance. The gait pattern of older subjects (n = 27) over both short (SWD <10 m) and long (LWD > 20 in) walking was evaluated using an ambulatory device consisting of body-worn

  8. The effect of walking aids on muscle activation patterns during walking in stroke patients

    NARCIS (Netherlands)

    Buurke, Jaap; Hermens, Hermanus J.; Erren-Wolters, C.V.; Nene, A.V.

    2005-01-01

    The purpose of this study was to investigate changes in muscle activation patterns with respect to timing and amplitude that occur when subjects with stroke walk with and without a walking aid. This knowledge could help therapists in deciding whether or not patients should use a cane or quad stick

  9. Walking and child pedestrian injury: a systematic review of built environment correlates of safe walking.

    Science.gov (United States)

    Rothman, Linda; Buliung, Ron; Macarthur, Colin; To, Teresa; Howard, Andrew

    2014-02-01

    The child active transportation literature has focused on walking, with little attention to risk associated with increased traffic exposure. This paper reviews the literature related to built environment correlates of walking and pedestrian injury in children together, to broaden the current conceptualization of walkability to include injury prevention. Two independent searches were conducted focused on walking in children and child pedestrian injury within nine electronic databases until March, 2012. Studies were included which: 1) were quantitative 2) set in motorized countries 3) were either urban or suburban 4) investigated specific built environment risk factors 5) had outcomes of either walking in children and/or child pedestrian roadway collisions (ages 0-12). Built environment features were categorized according to those related to density, land use diversity or roadway design. Results were cross-tabulated to identify how built environment features associate with walking and injury. Fifty walking and 35 child pedestrian injury studies were identified. Only traffic calming and presence of playgrounds/recreation areas were consistently associated with more walking and less pedestrian injury. Several built environment features were associated with more walking, but with increased injury. Many features had inconsistent results or had not been investigated for either outcome. The findings emphasise the importance of incorporating safety into the conversation about creating more walkable cities.

  10. Two- and 6-minute walk tests assess walking capability equally in neuromuscular diseases

    DEFF Research Database (Denmark)

    Andersen, Linda Kahr; Knak, Kirsten Lykke; Witting, Nanna

    2016-01-01

    OBJECTIVE: This methodologic study investigates if the 2-minute walk test (2MWT) can be a valid alternative to the 6-minute walk test (6MWT) to describe walking capability in patients with neuromuscular diseases. METHODS: Patients (n = 115) with different neuromuscular diseases were invited...... to participate on 2 test days, each consisting of 1 2MWT and 1 6MWT separated by a minimum 30-minute period of rest. The order of the walk tests was randomly assigned via sealed envelopes. A group of 38 healthy controls completed 1 6MWT. RESULTS: The mean walking distance for the 2MWT was 142.8 meters...... and for the 6MWT 405.3 meters. The distance walked in the 2MWT was highly correlated to the distance walked in the 6MWT (r = 0.99, p walking speed from the first to last minute in the 6MWT, both among patients and healthy controls, which was not evident in the 2MWT...

  11. Establishing the Range of Perceptually Natural Visual Walking Speeds for Virtual Walking-In-Place Locomotion

    DEFF Research Database (Denmark)

    Nilsson, Niels Christian; Serafin, Stefania; Nordahl, Rolf

    2014-01-01

    Walking-In-Place (WIP) techniques make it possible to facilitate relatively natural locomotion within immersive virtual environments that are larger than the physical interaction space. However, in order to facilitate natural walking experiences one needs to know how to map steps in place to virt...

  12. Walking for Well-Being: Are Group Walks in Certain Types of Natural Environments Better for Well-Being than Group Walks in Urban Environments?

    OpenAIRE

    Marselle, Melissa R.; Irvine, Katherine N.; Warber, Sara L.

    2013-01-01

    The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a ...

  13. Walk Score and Australian adults' home-based walking for transport.

    Science.gov (United States)

    Cole, Rachel; Dunn, Peter; Hunter, Ian; Owen, Neville; Sugiyama, Takemi

    2015-09-01

    The relationships of Walk Score, a publicly-accessible walkability assessment tool, with walking for transport to and from home were examined among a large representative sample of Australian adults aged 18-64 years (N=16,944). Residents in highly and somewhat walkable areas were twice and 1.4 times more likely to accumulate 30 min of walking per day compared to those in very car-dependent neighborhoods, respectively. Mean duration of walking was also longer for participants living in highly and somewhat walkable areas compared to those in very car-dependent areas. Walk Score has potential as a widely-applicable tool for identifying the walkability of local neighborhoods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Walking economy during cued versus non-cued self-selected treadmill walking in persons with Parkinson's disease.

    Science.gov (United States)

    Gallo, Paul M; McIsaac, Tara L; Garber, Carol Ewing

    2014-01-01

    Gait impairments related to Parkinson's disease (PD) include variable step length and decreased walking velocity, which may result in poorer walking economy. Auditory cueing is a common method used to improve gait mechanics in PD that has been shown to worsen walking economy at set treadmill walking speeds. It is unknown if auditory cueing has the same effects on walking economy at self-selected treadmill walking speeds. To determine if auditory cueing will affect walking economy at self-selected treadmill walking speeds and at speeds slightly faster and slower than self-selected. Twenty-two participants with moderate PD performed three, 6-minute bouts of treadmill walking at three speeds (self-selected and ± 0.22 m·sec-1). One session used cueing and the other without cueing. Energy expenditure was measured and walking economy was calculated (energy expenditure/power). Poorer walking economy and higher energy expenditure occurred during cued walking at a self-selected and a slightly faster walking speed, but there was no apparent difference at the slightly slower speed. These results suggest that potential gait benefits of auditory cueing may come at an energy cost and poorer walking economy for persons with PD at least at some treadmill walking speeds.

  15. Daily Quantity of Infant Leg Movement: Wearable Sensor Algorithm and Relationship to Walking Onset.

    Science.gov (United States)

    Smith, Beth A; Trujillo-Priego, Ivan A; Lane, Christianne J; Finley, James M; Horak, Fay B

    2015-08-04

    Normative values are lacking for daily quantity of infant leg movements. This is critical for understanding the relationship between the quantity of leg movements and onset of independent walking, and will begin to inform early therapy intervention for infants at risk for developmental delay. We used wearable inertial movement sensors to record full-day leg movement activity from 12 infants with typical development, ages 1-12 months. Each infant was tested three times across 5 months, and followed until the onset of independent walking. We developed and validated an algorithm to identify infant-produced leg movements. Infants moved their legs tens of thousands of times per day. There was a significant effect of leg movement quantity on walking onset. Infants who moved their legs more walked later than infants who moved their legs less, even when adjusting for age, developmental level or percentile length. We will need a much larger sample to adequately capture and describe the effect of movement experience on developmental rate. Our algorithm defines a leg movement in a specific way (each pause or change in direction is counted as a new movement), and further assessment of movement characteristics are necessary before we can fully understand and interpret our finding that infants who moved their legs more walked later than infants who moved their legs less. We have shown that typically-developing infants produce thousands of leg movements in a typical day, and that this can be accurately captured in the home environment using wearable sensors. In our small sample we can identify there is an effect of leg movement quantity on walking onset, however we cannot fully explain it.

  16. Scanning Tunneling Microscopy - image interpretation

    International Nuclear Information System (INIS)

    Maca, F.

    1998-01-01

    The basic ideas of image interpretation in Scanning Tunneling Microscopy are presented using simple quantum-mechanical models and supplied with examples of successful application. The importance is stressed of a correct interpretation of this brilliant experimental surface technique

  17. What Language Do Interpreters Speak?

    Science.gov (United States)

    Parks, Gerald B.

    1982-01-01

    States that both the register and variety of an interpreter's speech are quite limited and analyzes the linguistic characteristics of "International English," the English used by interpreters at international conferences. (CFM)

  18. Getting mobile with a walking-help

    DEFF Research Database (Denmark)

    Krummheuer, Antonia Lina; Raudaskoski, Pirkko Liisa

    in Symbolic Interaction 33: 443-457. Latour, B. (2005).Reassembeling the social. An Introduction to Actor-Network-Theory. Oxford University Press. Ryave, A. L. and J. N. Schenkein. (1974). Not es on the Art of Walking. In Turner, R. (ed.) Ethnomethodology. Selected Readings. Middlesex: Penguin, 265......Ethnomethodology has been one of the few fields were mundane experiences and social ordering such as walking have been a focus of interest (e.g. Ryave and Schenkein 1974). In the present paper we want to discuss how this mundane practice sometimes needs to be achieved through the help of technology...... of the technology (e.g. Gaver 1996), the bodily affordances (e.g. Sheller 2011) of the user and, furthermore, the scaffolding by an accompanying helper. The paper will discuss how movement as an enabled experience can be analysed as an entanglement of these three aspects. To do that, the situations of walk...

  19. Modeling, simulation and optimization of bipedal walking

    CERN Document Server

    Berns, Karsten

    2013-01-01

    The model-based investigation of motions of anthropomorphic systems is an important interdisciplinary research topic involving specialists from many fields such as Robotics, Biomechanics, Physiology, Orthopedics, Psychology, Neurosciences, Sports, Computer Graphics and Applied Mathematics. This book presents a study of basic locomotion forms such as walking and running is of particular interest due to the high demand on dynamic coordination, actuator efficiency and balance control. Mathematical models and numerical simulation and optimization techniques are explained, in combination with experimental data, which can help to better understand the basic underlying mechanisms of these motions and to improve them. Example topics treated in this book are Modeling techniques for anthropomorphic bipedal walking systems Optimized walking motions for different objective functions Identification of objective functions from measurements Simulation and optimization approaches for humanoid robots Biologically inspired con...

  20. Exotic states of bouncing and walking droplets

    DEFF Research Database (Denmark)

    Wind-Willassen, Øistein; Moláček, Jan; Harris, Daniel M.

    2013-01-01

    We present the results of an integrated experimental and theoretical investigation of droplets bouncing on a vibrating fluid bath. A comprehensive series of experiments provides the most detailed characterisation to date of the system's dependence on fluid properties, droplet size, and vibrational...... forcing. A number of new bouncing and walking states are reported, including complex periodic and aperiodic motions. Particular attention is given to the first characterisation of the different gaits arising within the walking regime. In addition to complex periodic walkers and limping droplets, we....... Molacek and J. W. M. Bush, J. Fluid Mech.727, 612-647 (2013)]10.1017/jfm.2013.280, which provide a basis for rationalising all observed bouncing and walking states....

  1. Coin state properties in quantum walks.

    Science.gov (United States)

    Souza, A M C; Andrade, R F S

    2013-01-01

    Recent experimental advances have measured individual coin components in discrete time quantum walks, which have not received the due attention in most theoretical studies on the theme. Here is presented a detailed investigation of the properties of M, the difference between square modulus of coin states of discrete quantum walks on a linear chain. Local expectation values are obtained in terms of real and imaginary parts of the Fourier transformed wave function. A simple expression is found for the average difference between coin states in terms of an angle θ gauging the coin operator and its initial state. These results are corroborated by numerical integration of dynamical equations in real space. The local dependence is characterized both by large and short period modulations. The richness of revealed patterns suggests that the amount of information stored and retrieved from quantum walks is significantly enhanced if M is taken into account.

  2. Design of a bipedal walking robot

    Science.gov (United States)

    Pratt, Jerry; Krupp, Ben

    2008-04-01

    We present the mechanical design of a bipedal walking robot named M2V2, as well as control strategies to be implemented for walking and balance recovery. M2V2 has 12 actuated degrees of freedom in the lower body: three at each hip, one at each knee, and two at each ankle. Each degree of freedom is powered by a force controllable Series Elastic Actuator. These actuators provide high force fidelity and low impedance, allowing for control techniques that exploit the natural dynamics of the robot. The walking and balance recovery controllers will use the concepts of Capture Points and the Capture Region in order to decide where to step. A Capture Point is a point on the ground in which a biped can step to in order to stop, and the Capture Region is the locus of such points.

  3. The debbuggable interpreter design pattern

    OpenAIRE

    Vrany, Jan; Bergel, Alexandre

    2007-01-01

    peer-reviewed The use of Interpreter and Visitor design patterns has been widely adopted to implement programming language interpreters due to their expressive and simple design. However, no general approach to conceive a debugger is commonly adopted. This paper presents the debuggable interpreter design pattern as a general approach to extend a language interpreter with debugging facilities such as step-over and step-into. Moreover, it enables multiple debuggers coexisting and extends ...

  4. Intercultural pragmatics and court interpreting

    DEFF Research Database (Denmark)

    Jacobsen, Bente

    2008-01-01

    . The court interpreters are all state-authorized court interpreters and thus fully competent professionals.   The centrality of pragmatics in triadic speech events has been demonstrated by a number of studies (e.g. Berk-Seligson 2002, Hale 2004, Jacobsen 2002). Thus, conversational implicatures, which....../Philadelphia: John Benjamins.   Jacobsen, B. (2002). Pragmatic meaning in court interpreting: An empirical study of additions in consecutively-interpreted question-answer dialogues. PhD thesis, The Aarhus School of Business....

  5. The interpretation of administrative contracts

    Directory of Open Access Journals (Sweden)

    Cătălin-Silviu SĂRARU

    2014-06-01

    Full Text Available The article analyzes the principles of interpretation for administrative contracts, in French law and in Romanian law. In the article are highlighted derogations from the rules of contract interpretation in common law. Are examined the exceptions to the principle of good faith, the principle of common intention (willingness of the parties, the principle of good administration, the principle of extensive interpretation of the administrative contract. The article highlights the importance and role of the interpretation in administrative contracts.

  6. Idiopathic toe walking and sensory processing dysfunction.

    Science.gov (United States)

    Williams, Cylie M; Tinley, Paul; Curtin, Michael

    2010-08-16

    It is generally understood that toe walking involves the absence or limitation of heel strike in the contact phase of the gait cycle. Toe walking has been identified as a symptom of disease processes, trauma and/or neurogenic influences. When there is no obvious cause of the gait pattern, a diagnosis of idiopathic toe walking (ITW) is made. Although there has been limited research into the pathophysiology of ITW, there has been an increasing number of contemporary texts and practitioner debates proposing that this gait pattern is linked to a sensory processing dysfunction (SPD). The purpose of this paper is to examine the literature and provide a summary of what is known about the relationship between toe walking and SPD. Forty-nine articles were reviewed, predominantly sourced from peer reviewed journals. Five contemporary texts were also reviewed. The literature styles consisted of author opinion pieces, letters to the editor, clinical trials, case studies, classification studies, poster/conference abstracts and narrative literature reviews. Literature was assessed and graded according to level of evidence. Only one small prospective, descriptive study without control has been conducted in relation to idiopathic toe walking and sensory processing. A cross-sectional study into the prevalence of idiopathic toe walking proposed sensory processing as being a reason for the difference. A proposed link between ITW and sensory processing was found within four contemporary texts and one conference abstract. Based on the limited conclusive evidence available, the relationship between ITW and sensory processing has not been confirmed. Given the limited number and types of studies together with the growing body of anecdotal evidence it is proposed that further investigation of this relationship would be advantageous.

  7. Quantum Interference, Graphs, Walks, and Polynomials.

    Science.gov (United States)

    Tsuji, Yuta; Estrada, Ernesto; Movassagh, Ramis; Hoffmann, Roald

    2018-04-09

    In this paper, we explore quantum interference (QI) in molecular conductance from the point of view of graph theory and walks on lattices. By virtue of the Cayley-Hamilton theorem for characteristic polynomials and the Coulson-Rushbrooke pairing theorem for alternant hydrocarbons, it is possible to derive a finite series expansion of the Green's function for electron transmission in terms of the odd powers of the vertex adjacency matrix or Hückel matrix. This means that only odd-length walks on a molecular graph contribute to the conductivity through a molecule. Thus, if there are only even-length walks between two atoms, quantum interference is expected to occur in the electron transport between them. However, even if there are only odd-length walks between two atoms, a situation may come about where the contributions to the QI of some odd-length walks are canceled by others, leading to another class of quantum interference. For nonalternant hydrocarbons, the finite Green's function expansion may include both even and odd powers. Nevertheless, QI can in some circumstances come about for nonalternants from cancellation of odd- and even-length walk terms. We report some progress, but not a complete resolution, of the problem of understanding the coefficients in the expansion of the Green's function in a power series of the adjacency matrix, these coefficients being behind the cancellations that we have mentioned. Furthermore, we introduce a perturbation theory for transmission as well as some potentially useful infinite power series expansions of the Green's function.

  8. Lexical Knowledge and Interpreter Attitude.

    Science.gov (United States)

    Skaaden, Hanne

    1999-01-01

    Examines the performance of six student interpreters attending a training course at the University of Oslo. Data are drawn from video recordings in which the students interpret dialogs in two test situations. Students use consecutive interpreting with short speaker intervals and perform in Norwegian/Bosnian, Croatian, Serbian. Compares students'…

  9. Student Interpretations of Political Cartoons.

    Science.gov (United States)

    Bedient, Douglas; Moore, David M.

    1985-01-01

    This study investigated the accuracy and types of interpretations that fifth, eighth, and eleventh graders gave to 24 editorial cartoons in four issue areas and the effect of intelligence on political cartoon interpretation. Numerous misinterpretations and no interpretations indicates assumptions that cartoons are an effective teaching medium…

  10. Interpretation of computed tomographic images

    International Nuclear Information System (INIS)

    Stickle, R.L.; Hathcock, J.T.

    1993-01-01

    This article discusses the production of optimal CT images in small animal patients as well as principles of radiographic interpretation. Technical factors affecting image quality and aiding image interpretation are included. Specific considerations for scanning various anatomic areas are given, including indications and potential pitfalls. Principles of radiographic interpretation are discussed. Selected patient images are illustrated

  11. Movement Behavior of High-Heeled Walking

    DEFF Research Database (Denmark)

    Alkjær, Tine; Raffalt, Peter Christian; Petersen, Nicolas Caesar

    2012-01-01

    The human locomotor system is flexible and enables humans to move without falling even under less than optimal conditions. Walking with high-heeled shoes constitutes an unstable condition and here we ask how the nervous system controls the ankle joint in this situation? We investigated the movement...... behavior of high-heeled and barefooted walking in eleven female subjects. The movement variability was quantified by calculation of approximate entropy (ApEn) in the ankle joint angle and the standard deviation (SD) of the stride time intervals. Electromyography (EMG) of the soleus (SO) and tibialis...

  12. The variability problem of normal human walking

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Alkjær, Tine

    2012-01-01

    a group of normal subjects and to test whether or not the expected differences would prove to be statistically significant. Fifteen healthy male subjects were recorded on video while they walked across two force platforms. Ten kinematic and kinetic parameters were selected and input to a statistical...... cluster analysis to determine whether or not the 15 subjects could be divided into different 'families' (clusters) of walking strategy. The net joint moments showed a variability corroborating earlier reports. The cluster analysis showed that the 15 subjects could be grouped into two clusters of 5 and 10...

  13. Rhythmic walking interaction with auditory feedback

    DEFF Research Database (Denmark)

    Maculewicz, Justyna; Jylhä, Antti; Serafin, Stefania

    2015-01-01

    We present an interactive auditory display for walking with sinusoidal tones or ecological, physically-based synthetic walking sounds. The feedback is either step-based or rhythmic, with constant or adaptive tempo. In a tempo-following experiment, we investigate different interaction modes...... and auditory feedback, based on the MSE between the target and performed tempo, and the stability of the latter. The results indicate that the MSE with ecological sounds is comparable to that with the sinusoidal tones, yet ecological sounds are considered more natural. Adaptive conditions result in stable...

  14. Path probabilities of continuous time random walks

    International Nuclear Information System (INIS)

    Eule, Stephan; Friedrich, Rudolf

    2014-01-01

    Employing the path integral formulation of a broad class of anomalous diffusion processes, we derive the exact relations for the path probability densities of these processes. In particular, we obtain a closed analytical solution for the path probability distribution of a Continuous Time Random Walk (CTRW) process. This solution is given in terms of its waiting time distribution and short time propagator of the corresponding random walk as a solution of a Dyson equation. Applying our analytical solution we derive generalized Feynman–Kac formulae. (paper)

  15. Path probabilities of continuous time random walks

    Science.gov (United States)

    Eule, Stephan; Friedrich, Rudolf

    2014-12-01

    Employing the path integral formulation of a broad class of anomalous diffusion processes, we derive the exact relations for the path probability densities of these processes. In particular, we obtain a closed analytical solution for the path probability distribution of a Continuous Time Random Walk (CTRW) process. This solution is given in terms of its waiting time distribution and short time propagator of the corresponding random walk as a solution of a Dyson equation. Applying our analytical solution we derive generalized Feynman-Kac formulae.

  16. Topics in random walks in random environment

    International Nuclear Information System (INIS)

    Sznitman, A.-S.

    2004-01-01

    Over the last twenty-five years random motions in random media have been intensively investigated and some new general methods and paradigms have by now emerged. Random walks in random environment constitute one of the canonical models of the field. However in dimension bigger than one they are still poorly understood and many of the basic issues remain to this day unresolved. The present series of lectures attempt to give an account of the progresses which have been made over the last few years, especially in the study of multi-dimensional random walks in random environment with ballistic behavior. (author)

  17. Neighborhood Walking and Social Capital: The Correlation between Walking Experience and Individual Perception of Social Capital

    Directory of Open Access Journals (Sweden)

    Heechul Kim

    2017-04-01

    Full Text Available The purpose of this study was to analyze the relationship between people’s actual walking experience and their social capital levels in order to examine the possibility of restoring weakened social functions of streets and public spaces in a walking-friendly urban environment. Based on the survey data of 591 residents of Seoul, we empirically analyzed the relationship between walking experience for various purposes and individual perceptions of social capital using one-way ANOVA and OLS regression models. As a result of the analysis, we found that the levels of neighborly trust and networking of people who experienced leisure walking were higher than those of people who did not, while there was no difference in the level of social capital according to walking experiences for other purposes. This result is significant in that it shows the basis for the restoration of the social function of neighborhoods through social capital formation of people as an effect of walking. Hence, it is important to create a walking environment that supports leisure activities.

  18. Race walking gait and its influence on race walking economy in world-class race walkers.

    Science.gov (United States)

    Gomez-Ezeiza, Josu; Torres-Unda, Jon; Tam, Nicholas; Irazusta, Jon; Granados, Cristina; Santos-Concejero, Jordan

    2018-03-06

    The aim of this study was to determine the relationships between biomechanical parameters of the gait cycle and race walking economy in world-class Olympic race walkers. Twenty-One world-class race walkers possessing the Olympic qualifying standard participated in this study. Participants completed an incremental race walking test starting at 10 km·h -1 , where race walking economy (ml·kg -1 ·km -1 ) and spatiotemporal gait variables were analysed at different speeds. 20-km race walking performance was related to race walking economy, being the fastest race walkers those displaying reduced oxygen cost at a given speed (R = 0.760, p economy (moderate effect, p economi cal than the lesser performers. Similarly, shorter flight times are associated with a more efficient race walking economy. Coaches and race walkers should avoid modifying their race walking style by increasing flight times, as it may not only impair economy, but also lead to disqualification.

  19. Walk Score® and Transit Score® and walking in the multi-ethnic study of atherosclerosis.

    Science.gov (United States)

    Hirsch, Jana A; Moore, Kari A; Evenson, Kelly R; Rodriguez, Daniel A; Diez Roux, Ana V

    2013-08-01

    Walk Score® and Transit Score® are open-source measures of the neighborhood built environment to support walking ("walkability") and access to transportation. To investigate associations of Street Smart Walk Score and Transit Score with self-reported transport and leisure walking using data from a large multicity and diverse population-based sample of adults. Data from a sample of 4552 residents of Baltimore MD, Chicago IL, Forsyth County NC, Los Angeles CA, New York NY, and St. Paul MN from the Multi-Ethnic Study of Atherosclerosis (2010-2012) were linked to Walk Score and Transit Score (collected in 2012). Logistic and linear regression models estimated ORs of not walking and mean differences in minutes walked, respectively, associated with continuous and categoric Walk Score and Transit Score. All analyses were conducted in 2012. After adjustment for site, key sociodemographic, and health variables, a higher Walk Score was associated with lower odds of not walking for transport and more minutes/week of transport walking. Compared to those in a "walker's paradise," lower categories of Walk Score were associated with a linear increase in odds of not transport walking and a decline in minutes of leisure walking. An increase in Transit Score was associated with lower odds of not transport walking or leisure walking, and additional minutes/week of leisure walking. Walk Score and Transit Score appear to be useful as measures of walkability in analyses of neighborhood effects. Copyright © 2013 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  20. Changing interpretations of Plotinus

    DEFF Research Database (Denmark)

    Catana, Leo

    2013-01-01

    th century, and that it remained absent in interpretative works produced between the 15th and 18th century. It is also argued that it is erroneous to assume that Plotinus presented a system of philosophy, or intended to do so — we do not find this concept in Plotinus’ writings, and his own statements......’ writings relatively late, in the 18th and 19th centuries, and that it was primarily made possible by Brucker’s methodology for history of philosophy, dating from the 1740s, in which the concept system of philosophy was essential. It is observed that the concept was absent in Ficino’s commentary from the 15...... about method point in other directions. Eduard Zeller (active in the second half of the 19th century) is typically regarded as the first who gave a satisfying account of Plotinus’ philosophy as a whole. In this article, on the other hand, Zeller is seen as the one who finalised a tradition initiated...

  1. Conducting psychotherapy with an interpreter.

    Science.gov (United States)

    Kuay, Justin; Chopra, Prem; Kaplan, Ida; Szwarc, Josef

    2015-06-01

    This qualitative study assessed how clinicians prepared and used interpreters during psychotherapeutic sessions and investigated the strategies they used to manage the dynamics of this process. Ten therapists were interviewed at the Victorian Foundation for the Survivors of Torture (VFST). A semi-structured interview format was used. Thematic analysis was conducted on transcripts of recorded interviews to identify key themes. Factors affecting the provision of psychotherapy with interpreters agreed with general guidelines for working with interpreters but there were exceptions. The possible roles of the interpreter as a cultural consultant, community advocate and co-therapist were explored. Specific troubleshooting strategies were identified for improving empathy, redefining roles, and adjusting interactions with interpreters. Working with interpreters in psychotherapy is a complex process. These findings may benefit clinicians providing psychotherapy to patients using interpreters. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  2. Reference equation for the 2-minute walk test in adults and the elderly.

    Science.gov (United States)

    Selman, Jessyca Pr; de Camargo, Anderson A; Santos, Jenifer; Lanza, Fernanda C; Dal Corso, Simone

    2014-04-01

    The 2-min walk test (2MWT) has been used in several health conditions, but the interpretation of its results is limited due to a lack of reference values. The aim of this study was to establish a reference equation to predict the distance walked (DW) in the 2MWT for healthy adults and the elderly and to test its reproducibility. We evaluated 390 healthy subjects (195 male), 18-89 y old, with normal spirometry and no history of previous chronic diseases. Two 2MWTs were performed on the same day, 30 min apart. To test the reliability of the prediction equation, 70 subjects (35 male) were prospectively included in the study. Men walked farther than women (221 [202-240] vs 199 [164-222] m, respectively; P model to predict DW (R(2) = 0.51). There was no difference between the DW by the subjects (197 [182-216] m) and that estimated by the prediction equation (197 [179-222] m) (P = .68). We established a prediction equation that may be used as a reference to interpret performance on the 2MWT of adults and the elderly with different health conditions.

  3. Exploration of walking behavior in Vermont using spatial regression.

    Science.gov (United States)

    2015-06-01

    This report focuses on the relationship between walking and its contributing factors by : applying spatial regression methods. Using the Vermont data from the New England : Transportation Survey (NETS), walking variables as well as 170 independent va...

  4. CDC Vital Signs: More People Walk to Better Health

    Science.gov (United States)

    ... exercise, or for activities such as walking the dog. The percentage of people who report walking at ... lower risk for heart disease, stroke, type 2 diabetes, depression, and some cancers. Improving spaces and having ...

  5. A smartphone-based system for automated detection of walking.

    Science.gov (United States)

    2015-08-01

    Walking is the most effective mode of travel to access transit: transit hubs with higher residential and employment densities have higher : ridership levels because they serve areas where a large population is within a short walk of transit service. ...

  6. Probability of walking in children with cerebral palsy in Europe

    DEFF Research Database (Denmark)

    Beckung, E.; Hagberg, G.; Uldall, P.

    2008-01-01

    OBJECTIVES: The purpose of this work was to describe walking ability in children with cerebral palsy from the Surveillance of Cerebral Palsy in Europe common database through 21 years and to examine the association between walking ability and predicting factors. PATIENTS AND METHODS: Anonymous data...... on 10042 children with cerebral palsy born between 1976 and 1996 were gathered from 14 European centers; 9012 patients were eligible for the analyses. RESULTS: Unaided walking as the primary way of walking at 5 years of age was reported for 54%, walking with assistive devices was reported for 16......%, and no walking ability was reported for 30%. The proportion of children who were unable to walk was rather stable over time in all of the centers, with a mean proportion of 28%. Walking ability related significantly to cerebral palsy types, that is, spastic unilateral, spastic bilateral, dyskinetic, and ataxic...

  7. Efficacy of walking aids on self-paced outdoor walking in individuals with COPD: A randomized cross-over trial.

    Science.gov (United States)

    Vaes, Anouk W; Meijer, Kenneth; Delbressine, Jeannet M; Wiechert, Jozé; Willems, Paul; Wouters, Emiel F M; Franssen, Frits M E; Spruit, Martijn A

    2015-08-01

    Walking aids, such as rollator or draisine, improve mobility and functional exercise performance in individuals with chronic obstructive pulmonary disease (COPD) during an indoor 6-min walk test. However, this test does not reflect everyday walking, which is the most frequently reported problematic activity of daily life in individuals with COPD. To date, efficacy of walking aids during self-paced outdoor walking remains unknown. Therefore, we aimed to determine the efficacy of a rollator and draisine on self-paced outdoor walking in individuals with COPD. Fifteen individuals with COPD (68% men; age: 63 ± 8 years; forced expiratory volume in 1 s: 40 ± 14% predicted) performed three self-paced outdoor walking tests on two consecutive days: test 1 unaided, and tests 2 and 3 with rollator or draisine in random order. Participants had to walk as long as possible at their own pace. The test ended when participants needed to stop, with a maximum duration of 30 min. The use of rollator resulted in the highest walk distance and time (P walked significantly further and longer during an unaided test compared with a draisine aided test (P walking speed, fewer strides, greater stride length, and higher step and stride variability (P walk distance and time in individuals with moderate and advanced COPD and a poor functional exercise capacity, whereas the use of a draisine had a detrimental effect compared with unaided walking. © 2015 Asian Pacific Society of Respirology.

  8. Random Walk Method for Potential Problems

    Science.gov (United States)

    Krishnamurthy, T.; Raju, I. S.

    2002-01-01

    A local Random Walk Method (RWM) for potential problems governed by Lapalace's and Paragon's equations is developed for two- and three-dimensional problems. The RWM is implemented and demonstrated in a multiprocessor parallel environment on a Beowulf cluster of computers. A speed gain of 16 is achieved as the number of processors is increased from 1 to 23.

  9. Random walk term weighting for information retrieval

    DEFF Research Database (Denmark)

    Blanco, R.; Lioma, Christina

    2007-01-01

    We present a way of estimating term weights for Information Retrieval (IR), using term co-occurrence as a measure of dependency between terms.We use the random walk graph-based ranking algorithm on a graph that encodes terms and co-occurrence dependencies in text, from which we derive term weights...

  10. WALK OR JOG FOR HEALTH: 11*

    African Journals Online (AJOL)

    test of maximum oxygen intake which requires neither special equipment nor trained technical staff. Cooper's 12- minute walk or run procedure for predicting the maximum oxygen intake appears to fulfil these requirements.' All that is needed is a stop-watch and a level 440-yard track so that the distance which the individual ...

  11. Adaptive Nonlinear Tracking for Robotic Walking

    Czech Academy of Sciences Publication Activity Database

    Dolinský, Kamil; Čelikovský, Sergej

    2012-01-01

    Roč. 1, č. 1 (2012), s. 28-35 ISSN 2223-7038 Institutional research plan: CEZ:AV0Z10750506 Keywords : Adaptive control * Kalman filter * walking robots Subject RIV: BC - Control Systems Theory http://lib.physcon.ru/doc?id=9e51935aa5bc

  12. Go Naked: Diapers Affect Infant Walking

    Science.gov (United States)

    Cole, Whitney G.; Lingeman, Jesse M.; Adolph, Karen E.

    2012-01-01

    In light of cross-cultural and experimental research highlighting effects of childrearing practices on infant motor skill, we asked whether wearing diapers, a seemingly innocuous childrearing practice, affects infant walking. Diapers introduce bulk between the legs, potentially exacerbating infants' poor balance and wide stance. We show that…

  13. A Random Walk on a Circular Path

    Science.gov (United States)

    Ching, W.-K.; Lee, M. S.

    2005-01-01

    This short note introduces an interesting random walk on a circular path with cards of numbers. By using high school probability theory, it is proved that under some assumptions on the number of cards, the probability that a walker will return to a fixed position will tend to one as the length of the circular path tends to infinity.

  14. Brownian Motion Problem: Random Walk and Beyond

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 8. Brownian Motion Problem: Random Walk and Beyond. Shama Sharma Vishwamittar. General Article Volume 10 Issue 8 August 2005 pp 49-66. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. Pollen Grains, Random Walks and Einstein

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 3. Pollen Grains, Random Walks and Einstein. Sriram Ramaswamy. General Article Volume 5 Issue 3 March 2000 pp 16-34. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/005/03/0016-0034 ...

  16. Pollen Grains, Random Walks and Einstein

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 12. Pollen Grains, Random Walks and Einstein. Sriram Ramaswamy. Volume 10 Issue 12 December 2005 pp 106-124. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/010/12/0106-0124 ...

  17. Garden walking for depression: a research report.

    Science.gov (United States)

    McCaffrey, Ruth; Hanson, Claire; McCaffrey, William

    2010-01-01

    This study was designed to determine the effect of garden walking and reflective journaling on adults who are 65 years old and older with depression. The Geriatric Depression Scale measured depression. Four themes emerged from the interview data collected from each participant.

  18. Iterated random walks with shape prior

    DEFF Research Database (Denmark)

    Pujadas, Esmeralda Ruiz; Kjer, Hans Martin; Piella, Gemma

    2016-01-01

    We propose a new framework for image segmentation using random walks where a distance shape prior is combined with a region term. The shape prior is weighted by a confidence map to reduce the influence of the prior in high gradient areas and the region term is computed with k-means to estimate th...

  19. Walking training for intermittent claudication in diabetes

    NARCIS (Netherlands)

    Ubels, FL; Links, TP; Sluiter, WJ; Smit, AJ

    OBJECTIVE - Walking training (WT) is an established treatment for patients with intermittent claudication (IC). Abnormalities specific to diabetes, such as a relative preponderance of distal lesions and the contribution of microcirculatory disease, might well influence the results of WT. We compared

  20. Assessment of a Solar System Walk

    Science.gov (United States)

    LoPresto, Michael C.; Murrell, Steven R.; Kirchner, Brian

    2010-01-01

    The idea of sending students and the general public on a walk through a scale model of the solar system in an attempt to instill an appreciation of the relative scales of the sizes of the objects compared to the immense distances between them is certainly not new. A good number of such models exist, including one on the National Mall in…

  1. Analysis, Control and Design of Walking Robots

    NARCIS (Netherlands)

    van Oort, Gijs

    2011-01-01

    In this thesis five research questions are discussed that are related to the development of two-legged (bipedal) walking robots. The research questions are categorized in three main topics: analysis, control and actuation and design. The research questions are: - How can we analyze the behavior of a

  2. A New View of Walk-Throughs

    Science.gov (United States)

    Moss, Connie M.; Brookhart, Susan M.

    2013-01-01

    Traditionally, principals have used walk-throughs to determine whether teachers are implementing strategies that the principal believes define good teaching. In this model, the principal is the expert, and the teacher is the learner. Connie M. Moss and Susan M. Brookhart believe that this approach can cause the principal to disregard the classroom…

  3. Efficient quantum circuits for Szegedy quantum walks

    Science.gov (United States)

    Loke, T.; Wang, J. B.

    2017-07-01

    A major advantage in using Szegedy's formalism over discrete-time and continuous-time quantum walks lies in its ability to define a unitary quantum walk by quantizing a Markov chain on a directed or weighted graph. In this paper, we present a general scheme to construct efficient quantum circuits for Szegedy quantum walks that correspond to classical Markov chains possessing transformational symmetry in the columns of the transition matrix. In particular, the transformational symmetry criteria do not necessarily depend on the sparsity of the transition matrix, so this scheme can be applied to non-sparse Markov chains. Two classes of Markov chains that are amenable to this construction are cyclic permutations and complete bipartite graphs, for which we provide explicit efficient quantum circuit implementations. We also prove that our scheme can be applied to Markov chains formed by a tensor product. We also briefly discuss the implementation of Markov chains based on weighted interdependent networks. In addition, we apply this scheme to construct efficient quantum circuits simulating the Szegedy walks used in the quantum Pagerank algorithm for some classes of non-trivial graphs, providing a necessary tool for experimental demonstration of the quantum Pagerank algorithm.

  4. Random walk centrality for temporal networks

    International Nuclear Information System (INIS)

    Rocha, Luis E C; Masuda, Naoki

    2014-01-01

    Nodes can be ranked according to their relative importance within a network. Ranking algorithms based on random walks are particularly useful because they connect topological and diffusive properties of the network. Previous methods based on random walks, for example the PageRank, have focused on static structures. However, several realistic networks are indeed dynamic, meaning that their structure changes in time. In this paper, we propose a centrality measure for temporal networks based on random walks under periodic boundary conditions that we call TempoRank. It is known that, in static networks, the stationary density of the random walk is proportional to the degree or the strength of a node. In contrast, we find that, in temporal networks, the stationary density is proportional to the in-strength of the so-called effective network, a weighted and directed network explicitly constructed from the original sequence of transition matrices. The stationary density also depends on the sojourn probability q, which regulates the tendency of the walker to stay in the node, and on the temporal resolution of the data. We apply our method to human interaction networks and show that although it is important for a node to be connected to another node with many random walkers (one of the principles of the PageRank) at the right moment, this effect is negligible in practice when the time order of link activation is included. (paper)

  5. Random walk centrality for temporal networks

    Science.gov (United States)

    Rocha, Luis E. C.; Masuda, Naoki

    2014-06-01

    Nodes can be ranked according to their relative importance within a network. Ranking algorithms based on random walks are particularly useful because they connect topological and diffusive properties of the network. Previous methods based on random walks, for example the PageRank, have focused on static structures. However, several realistic networks are indeed dynamic, meaning that their structure changes in time. In this paper, we propose a centrality measure for temporal networks based on random walks under periodic boundary conditions that we call TempoRank. It is known that, in static networks, the stationary density of the random walk is proportional to the degree or the strength of a node. In contrast, we find that, in temporal networks, the stationary density is proportional to the in-strength of the so-called effective network, a weighted and directed network explicitly constructed from the original sequence of transition matrices. The stationary density also depends on the sojourn probability q, which regulates the tendency of the walker to stay in the node, and on the temporal resolution of the data. We apply our method to human interaction networks and show that although it is important for a node to be connected to another node with many random walkers (one of the principles of the PageRank) at the right moment, this effect is negligible in practice when the time order of link activation is included.

  6. Sound design and perception in walking interactions

    DEFF Research Database (Denmark)

    Visell, Yon; Fontana, Federico; Giordano, Bruno

    2009-01-01

    This paper reviews the state of the art in the display and perception of walking generated sounds and tactile vibrations, and their current and potential future uses in interactive systems. As non-visual information sources that are closely linked to human activities in diverse environments...

  7. The Physics of a Walking Robot

    Science.gov (United States)

    Guemez, J.; Fiolhais, M.

    2013-01-01

    The physics of walking is explored, using a toy as a concrete example and a "toy model" applied to it. Besides using Newton's second law, the problem is also discussed from the thermodynamical perspective. Once the steady state (constant velocity) is achieved, we show that the internal energy of the toy is dissipated as heat in the…

  8. Orientalismi: nuove prospettive interpretative

    Directory of Open Access Journals (Sweden)

    Gabriele Proglio

    2012-11-01

    Full Text Available This paper is aimed at reconsidering the concept of Orientalism in a new and multiple perspective, and at proposing a different interpretation of the relationship between culture and power, starting from Edward Said’s theoretical frame of reference. If Said’s representational model is repositioned out of structuralist and foucaultian frameworks and separated from the gramscian idea of hegemony-subordination, indeed, it may be possible to re-discuss the traditional profile identifying the Other in the European cultures. My basic assumption here is that Orientalism should not be understood as a consensus mechanism, which is able to produce diversified images of the Orient and the Oriental on demand. Although, of course, in most cases Orientalism is connected to the issue of power, its meanings could also be explained —as it will be soon shown— otherwise. Let’s take The Invisible Cities by Italo Calvino as an example. Here the narratives are not just multiple repetitions of Venice —in Said’s case, the same would hold for Europeanism—, but they could be strategically re-appropriated by those “others” and “alterities” whose bodies and identities are imposed by the Eurocentric discourse. In this sense, a double link may be identified with queer theories and postcolonial studies, and the notion of subordination will be rethought. Finally, from the above mentioned borders, a new idea of image emerges, which appears as linear, uniform and flattened only to the European gaze, whereas in actual fact it is made of imaginaries and forms of knowledge, which combine representation with the conceptualization of power relationships.

  9. Continuous-time quantum walks on star graphs

    International Nuclear Information System (INIS)

    Salimi, S.

    2009-01-01

    In this paper, we investigate continuous-time quantum walk on star graphs. It is shown that quantum central limit theorem for a continuous-time quantum walk on star graphs for N-fold star power graph, which are invariant under the quantum component of adjacency matrix, converges to continuous-time quantum walk on K 2 graphs (complete graph with two vertices) and the probability of observing walk tends to the uniform distribution.

  10. Identifying Walking Trips Using GPS Data.

    Science.gov (United States)

    Cho, Gi-Hyoug; Rodríguez, Daniel A; Evenson, Kelly R

    2011-02-01

    this study developed and tested algorithms to identify outdoor walking trips from portable global positioning system (GPS) units in free-living conditions. the study included a calibration and a validation phase. For the calibration phase, we determined the best algorithm from 35 person-days of data. Measures of agreement regarding the daily number and duration of diary-reported and GPS-identified trips were used. In the validation phase, the best algorithm was applied to an additional and separate 136 person-days of diary and GPS data. the preferred algorithm in the calibration phase resulted in 90% of trips identified from the GPS data being found in the diary, whereas 81% of trips reported in the diary being found in the GPS data. The preferred algorithm used 1) a maximum 3-min gap between points to define a trip, 2) at least 5 min or more of continuous GPS points, 3) a speed range between 2 and 8.0 km·h, 4) at least 30 m of displacement between the start and end points of a trip, and 5) merged walking trips when the time gap between trips was less than 3 min. With the validation data, substantial agreement between the GPS and the diary was achieved, with 86% of trips identified from the GPS data found in the diary and 77% of trips reported in the diary found in the GPS data. the algorithm identified free-living walking trips of more than 5 min in duration. The ability to identify outdoor walking trips from GPS data can be improved by reducing recording intervals used in the GPS units and monitoring participant compliance. Further research is desirable to determine whether concurrent wearing of an accelerometer may improve the ability to detect walking more accurately.

  11. How might we increase physical activity through dog walking?: A comprehensive review of dog walking correlates

    OpenAIRE

    Westgarth, Carri; Christley, Robert M; Christian, Hayley E

    2014-01-01

    Background Physical inactivity and sedentary behaviour are major threats to population health. A considerable proportion of people own dogs, and there is good evidence that dog ownership is associated with higher levels of physical activity. However not all owners walk their dogs regularly. This paper comprehensively reviews the evidence for correlates of dog walking so that effective interventions may be designed to increase the physical activity of dog owners. Methods Published findings fro...

  12. Relationship between walk tests and parental reports of walking abilities in children with cerebral palsy.

    Science.gov (United States)

    Chong, Jimmy; Mackey, Anna H; Broadbent, Elizabeth; Stott, N Susan

    2011-02-01

    To test the strength of association between 2 clinic-based measures of walking ability, the 1-minute walk test (1MWT) and the six-minute walk test (6MWT), and the parental report of usual walking performance, measured by the ABILOCO-Kids logit score, in children with cerebral palsy (CP). Observational study. Tertiary level outpatient clinics. Children and youth with CP (N=60; 32 boys, 28 girls; mean age, 11.2y [range, 5-18y]), Gross Motor Function Classification System (GMFCS) level I to IV. Not applicable. The 10-item ABILOCO-Kids questionnaire, the 1MWT, and the 6MWT. ABILOCO-Kids logit scores were significantly correlated with the 1MWT (ρ=.70, Pwalking distance, depending on GMFCS level (P=.06 1MWT; P=.14 6MWT). The strongest relationship was observed at GMFCS level II, where ABILOCO-Kids score predicted 33% of variance in 1MWT (P=.003) and 31% of 6MWT (P=.003). The weakest relationship was at GMFCS level I, where ABILOCO-Kids score predicted only 5% of the variance in 1MWT (P=.33) and 16% of the variance in 6MWT (P=.08). Parental perceptions of their child's walking ability in the community correlate with clinic-based walking tests in ambulatory children with CP, providing evidence of convergent validity for the 1MWT and 6MWT. However, parents report a much wider range of walking abilities in children who function at a high level (GMFCS I) than is reflected by their walk test results. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  13. Exploring Muscle Activation during Nordic Walking: A Comparison between Conventional and Uphill Walking.

    Science.gov (United States)

    Pellegrini, Barbara; Peyré-Tartaruga, Leonardo Alexandre; Zoppirolli, Chiara; Bortolan, Lorenzo; Bacchi, Elisabetta; Figard-Fabre, Hélène; Schena, Federico

    2015-01-01

    Nordic Walking (NW) owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W). Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2) performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2) were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill.

  14. The Not-so-Random Drunkard's Walk

    Science.gov (United States)

    Ehrhardt, George

    2013-01-01

    This dataset contains the results of a quasi-experiment, testing Karl Pearson's "drunkard's walk" analogy for an abstract random walk. Inspired by the alternate hypothesis that drunkards stumble to the side of their dominant hand, it includes data on intoxicated test subjects walking a 10' line. Variables include: the…

  15. Branching random walks with displacements coming from a power law

    Indian Academy of Sciences (India)

    Parthanil Roy Joint work with Ayan Bhattacharya and Rajat Subhra Hazra

    2015-07-04

    Jul 4, 2015 ... What is a Branching Random Walk ? Rougly speaking, a branching random walk is a growing collection of particles (or organisms) which starts from a single particle, branch and spread independently of their positions and of the other particles. Parthanil Roy (I.S.I.). Branching random walk. July 04, 2015.

  16. Speed dependence of averaged EMG profiles in walking

    NARCIS (Netherlands)

    Hof, AL; Elzinga, H; Grimmius, W; Halbertsma, JPK

    Electromyogram (EMG) profiles strongly depend on walking speed and, in pathological gait, patients do not usually walk at normal speeds. EMG data was collected from 14 muscles in two groups of healthy young subjects who walked at five different speeds ranging from 0.75 to 1.75 ms(-1). We found that

  17. Quantum random walks and their convergence to Evans–Hudson ...

    Indian Academy of Sciences (India)

    Quantum dynamical semigroup; Evans–Hudson flow; quantum random walk. 1. Introduction. The aim of this article is to investigate convergence of random walks on von Neumann algebra to Evans–Hudson flows. Here the random walks and Evans–Hudson flows are gene- ralizations of classical Markov chains and Markov ...

  18. Branching random walks with displacements coming from a power law

    Indian Academy of Sciences (India)

    Parthanil Roy Joint work with Ayan Bhattacharya and Rajat Subhra Hazra

    2015-07-04

    Jul 4, 2015 ... Branching Random Walk: Description in Words. Parthanil Roy (I.S.I.). Branching random walk. July 04, 2015. 6 / 14 ... independent of each other. This gives rise to the Generation 1. The displacements are (positive and) independent of the branching mechanism. Parthanil Roy (I.S.I.). Branching random walk.

  19. Modeling Framework and Software Tools for Walking Robots

    NARCIS (Netherlands)

    Duindam, V.; Stramigioli, Stefano; Groen, F.N.J.

    2005-01-01

    In research on passive dynamic walking, the aim is to study and design robots that walk naturally, i.e., with little or no control effort. McGeer [1] and others (e.g. [2, 3]) have shown that, indeed, robots can walk down a shallow slope with no actuation, only powered by gravity. In this work, we

  20. The Walking Classroom: Active Learning Is Just Steps Away!

    Science.gov (United States)

    Becker, Kelly Mancini

    2016-01-01

    Walking is a viable and valuable form of exercise for young children that has both physical and mental health benefits. There is much evidence showing that school-age children are not getting the recommended 60 minutes of daily exercise. A school-wide walking program can be a great way to encourage walking in and out of school, can be aligned with…

  1. Walking...A Step in the Right Direction!

    Science.gov (United States)

    ... part of your daily routine. What are the benefits of walking? Two benefits of walking are that it’s easy to do and has ... own, with walkers, or with other aids. Health benefits Like other kinds of regular physical activity, walking at a brisk pace also may offer health ...

  2. Variable bipedal walking gait with variable leg stiffness

    NARCIS (Netherlands)

    Roozing, W.M.; Visser, L.C.; Carloni, Raffaella

    The Spring-Loaded Inverted Pendulum (SLIP) model has been shown to exhibit many properties of human walking, and therefore has been the starting point for studies on robust, energy-efficient walking for robots. In this paper, the problem of gait variation during walking on the SLIP model is

  3. Walking on four limbs: A systematic review of Nordic Walking in Parkinson disease.

    Science.gov (United States)

    Bombieri, Federica; Schena, Federico; Pellegrini, Barbara; Barone, Paolo; Tinazzi, Michele; Erro, Roberto

    2017-05-01

    Nordic Walking is a relatively high intensity activity that is becoming increasingly popular. It involves marching using poles adapted from cross-country skiing poles in order to activate upper body muscles that would not be used during normal walking. Several studies have been performed using this technique in Parkinson disease patients with contradictory results. Thus, we reviewed here all studies using this technique in Parkinson disease patients and further performed a meta-analysis of RCTs where Nordic Walking was evaluated against standard medical care or other types of physical exercise. Nine studies including four RCTs were reviewed for a total of 127 patients who were assigned to the Nordic Walking program. The majority of studies reported beneficial effects of Nordic Walking on either motor or non-motor variables, but many limitations were observed that hamper drawing definitive conclusions and it is largely unclear whether the benefits persist over time. It would appear that little baseline disability is the strongest predictor of response. The meta-analysis of the 4 RCTs yielded a statistically significant reduction of the UPDRS-3 score, but its value of less than 1 point does not appear to be clinically meaningful. Well-designed, large RCTs should be performed both against standard medical care and other types of physical exercise to definitively address whether Nordic Walking can be beneficial in PD. Copyright © 2017. Published by Elsevier Ltd.

  4. Working memory and simultaneous interpreting

    OpenAIRE

    Timarova, Sarka

    2009-01-01

    Working memory is a cognitive construct underlying a number of abilities, and it has been hypothesised for many years that it is crucial for interpreting. A number of studies have been conducted with the aim to support this hypothesis, but research has not yielded convincing results. Most researchers focused on studying working memory differences between interpreters and non-interpreters with the rationale that differences in working memory between the two groups would provide evidence of wor...

  5. Assessment of Interpretive Facilities and the Delivery of Interpretive ...

    African Journals Online (AJOL)

    Assessment of interpretive facilities and the delivery of interpretive services in Chad Basin National Park (CBNP), Kainji Lake National Park (KLNP), Okomu National Park (OKNP), and Yankari National Park (YNP) were conducted. The parks were selected to represent the major ecological zones where National Parks are ...

  6. Brief Walks in Outdoor and Laboratory Environments: Effects on Affective Responses, Enjoyment, and Intentions to Walk for Exercise

    Science.gov (United States)

    Focht, Brian C.

    2009-01-01

    The purpose of this study was to compare the effect of brief walks completed in outdoor and laboratory environments on affective responses, enjoyment, and intention to walk for exercise. Thirty-five active young women (M age = 22.14 years, SD = 1.73) walked for 10 min at a self-selected intensity in outdoor and laboratory environments. Affective…

  7. Persistence of locomotor-related interlimb reflex networks during walking after stroke.

    Science.gov (United States)

    Zehr, E Paul; Loadman, Pamela M

    2012-04-01

    Cutaneous nerve stimulation evokes coordinated and phase-modulated reflex output widely distributed to muscles of all four limbs during walking. Accessibility to this distributed network after stroke offers insight into the pathological changes and suggests utility for therapeutic applications. Here we examined muscles in both the more (MA) and less affected (LA) legs evoked by stimulation at the ankle and wrist during walking in chronic (>6 months post CVA) stroke. Stroke and control participants walked on a treadmill with a harness support system. Reflexes were evoked with trains of electrical stimuli delivered separately to the cutaneous superficial peroneal (SP; at the ankle) and superficial radial (SR; at the wrist) nerves. Background locomotor and reflex EMG were phase-averaged across the gait cycle and analyzed off line. Locomotor background muscle activation patterns were altered bilaterally in stroke, as compared with control. Phase-dependent modulation of interlimb cutaneous reflexes was found in both stroke and control subjects with stimulation of each nerve, but responses were blunted in stroke. Reflex reversal in tibialis anterior (TA) at heel strike with SP nerve stimulation was present in both groups. Notably, SR nerve stimulation produced facilitation during the swing-to-stance transition in the TA and suppression of MG in the MA leg during stance. Interlimb cutaneous inputs may access coordinated reflex pathways in the MA limb during walking after stroke. Importantly activation in these pathways could provoke responses to counter foot drop during swing phase of walking. Additionally, our data support the perspective that there is no "unaffected" side after stroke and that caution should be used when interpreting the LA side as "control" after stroke. The presence of functionally-relevant interlimb cutaneous reflexes in the MA leg presents a substrate that may be strengthened by rehabilitation. Copyright © 2011 International Federation of Clinical

  8. About the walking machine motion stability

    Directory of Open Access Journals (Sweden)

    V. V. Lapshin

    2014-01-01

    Full Text Available The use of legs as propulsive devices of the machine will increase its capability to cross rough and deformable terrain as compared with wheeled and trucked machines. Today it is already possible to speak about design of statically stable walking robots to be used in the certain areas of application. The most promising areas of their application are exploration and emergency-rescue operations in extremely complicated situations (e.g. in the zone of destruction after earthquakes, technogenic catastrophe, etc..In such dangerous situations there is a possibility for the walking machine to be overturned either because of loosing a support to one or several legs or due to significant displacement of the leg support points, which are caused by deformation or destruction of the terrain in the points of the legs support. Therefore, it is necessary to design motion control algorithms that enable teaching the motion control system of a walking robot: How to decrease the possibility of the robot overturning? How to stop the robot as quickly as possible keeping its static stability? What must be done if static stability is lost? Note that the loss of static stability does not inevitably result in the robot falling down. How to fall down better (with minimal robot destruction in inevitable case?This work investigates the first abovementioned problems, i.e. preventing a walking machine from overturning in dangerous situations. For this purpose it suggests to use a special cautious (safe gait, which allows the machine to remain statically stable if it suddenly looses support to its any leg. The natural price for the increased safety to prevent from overturning is the reduced capabilities of robot kinematics and, as a consequence, its capability to cross rough terrain. It is also suggested to reconsider the general definition of a walking machine static stability margin in order to obtain an adequate estimation of the robot overturning possibility

  9. Transit-Related Walking to Work in Promoting Physical Activity.

    Science.gov (United States)

    Yu, Chia-Yuan; Lin, Hsien-Chang

    2015-04-01

    Transit-related walking to work is a potential strategy for incorporating physical activity into daily life and promoting health benefits. This study estimated the transit-related walking time for work trips on the journey to and from work and examined the predictors of transit users who walked to/from transit and the workplace and those who walked 30 minutes or more per day. This study used the 2009 National Household Travel Survey and identified 772 subjects who took transit to/from work, 355 subjects who walked to/from transit and the workplace, and 145 subjects who walked 30 minutes or more per day among the 40,659 workers. Weighted logistic regressions were used for the analysis. Of the people who walked to/from transit and the workplace, 40.9% walked 30 minutes or more per day. The weighted logistic regressions revealed that low-income groups and workers living in high population density areas were more likely to walk to/from transit and the workplace. Workers living in high population density areas were more likely to walk 30 minutes or more per day. Transit-related walking to work provides an opportunity to increase physical activity levels and to meet the physical activity recommendations.

  10. Distracted walking: Examining the extent to pedestrian safety problems

    Directory of Open Access Journals (Sweden)

    Judith Mwakalonge

    2015-10-01

    Full Text Available Pedestrians, much like drivers, have always been engaged in multi-tasking like using hand-held devices, listening to music, snacking, or reading while walking. The effects are similar to those experienced by distracted drivers. However, distracted walking has not received similar policies and effective interventions as distracted driving to improve pedestrian safety. This study reviewed the state-of-practice on policies, campaigns, available data, identified research needs, and opportunities pertaining to distracted walking. A comprehensive review of literature revealed that some of the agencies/organizations disseminate useful information about certain distracting activities that pedestrians should avoid while walking to improve their safety. Various walking safety rules/tips have been given, such as not wearing headphones or talking on a cell phone while crossing a street, keeping the volume down, hanging up the phone while walking, being aware of traffic, and avoiding distractions like walking with texting. The majority of the past observational-based and experimental-based studies reviewed in this study on distracted walking is in agreement that there is a positive correlation between distraction and unsafe walking behavior. However, limitations of the existing crash data suggest that distracted walking may not be a severe threat to the public health. Current pedestrian crash data provide insufficient information for researchers to examine the extent to which distracted walking causes and/or contributes to actual pedestrian safety problems.

  11. Using interpretation services during clerkships

    NARCIS (Netherlands)

    Lijbers, Laura; Gerritsen, Debby; Suurmond, Jeanine

    2017-01-01

    Although using professional interpreters is known to improve health outcomes for patients when language barriers are present, care providers often hesitate to use them. Training in how to use interpreters has been effective in increasing students' knowledge and self-efficacy, but little is known

  12. Basic Interpreting Strategies for Parents.

    Science.gov (United States)

    Luetke-Stahlman, Barbara

    1993-01-01

    Some deaf interpreting strategies are offered to parents of children who are deaf or hard of hearing. Parents are urged to utilize space in their interpreting, use name signs, utilize sight lines to distinguish characters in stories, use exaggerated signs to translate nursery rhymes, place themselves carefully at a public performance, and learn…

  13. Pragmatics in Court Interpreting: Additions

    DEFF Research Database (Denmark)

    Jacobsen, Bente

    2003-01-01

    Danish court interpreters are expected to follow ethical guidelines, which instruct them to deliver exact verbatim versions of source texts. However, this requirement often clashes with the reality of the interpreting situation in the courtroom. This paper presents and discusses the findings...

  14. Interpreting Recoil for Undergraduate Students

    Science.gov (United States)

    Elsayed, Tarek A.

    2012-01-01

    The phenomenon of recoil is usually explained to students in the context of Newton's third law. Typically, when a projectile is fired, the recoil of the launch mechanism is interpreted as a reaction to the ejection of the smaller projectile. The same phenomenon is also interpreted in the context of the conservation of linear momentum, which is…

  15. Random walks, random fields, and disordered systems

    CERN Document Server

    Černý, Jiří; Kotecký, Roman

    2015-01-01

    Focusing on the mathematics that lies at the intersection of probability theory, statistical physics, combinatorics and computer science, this volume collects together lecture notes on recent developments in the area. The common ground of these subjects is perhaps best described by the three terms in the title: Random Walks, Random Fields and Disordered Systems. The specific topics covered include a study of Branching Brownian Motion from the perspective of disordered (spin-glass) systems, a detailed analysis of weakly self-avoiding random walks in four spatial dimensions via methods of field theory and the renormalization group, a study of phase transitions in disordered discrete structures using a rigorous version of the cavity method, a survey of recent work on interacting polymers in the ballisticity regime and, finally, a treatise on two-dimensional loop-soup models and their connection to conformally invariant systems and the Gaussian Free Field. The notes are aimed at early graduate students with a mod...

  16. Trying-out a walking help

    DEFF Research Database (Denmark)

    Krummheuer, Antonia Lina; Raudaskoski, Pirkko Liisa

    2016-01-01

    that constitute the trial as a joint activity in which the impaired participant becomes a competent participant and independent walker. The analysis is based on video recordings from a case study in which a person with brain injury is trying out a new type of walking help. The trial is understood as a situated...... learning process in which the participants prepare, enact and assess the performance of the technology supported walking. The paper distinguishes two iterative phases in which the impaired person is constituted as an independent walker: the adjustment and assessment of a body-device relation and, further......The paper contributes to the discussion of how people with limited communication means become active participants in the assessment of welfare technologies. The paper combines ethnomethodology with insights form Science and Technology Studies and emphasises the situated and multimodal practices...

  17. Discrete Dynamical Models of Walking Droplets

    Science.gov (United States)

    Rahman, Aminur

    2017-11-01

    In recent years discrete planar dynamical models of walking droplets (walkers) on a billiards table (Shirokoff, Chaos 2013) and walking in a straight-line confined geometry (Gilet, PRE 2014) have been developed. Gilet's model was then analyzed via dynamical systems theory (Rahman-Blackmore, C,S& F 2016). From the analysis it was shown that while Gilet's walker is confined under the threshold for chaos, it does escape the boundary once the system becomes chaotic. We modify the model to trap the walker in an annulur domain. This allows for connections between the dynamics, statistics, and experimental works (Filoux et al., PRE 2015). From this connection we derive a kicked rotator-like model for a walker in an annulus. We endeavor to manipulate the dynamics of the model to produce statistics similar to that of experiments.

  18. The Walking Egg non-profit organisation.

    Science.gov (United States)

    Dhont, N

    2011-01-01

    The Walking Egg non-profit organisation (npo) was founded in 2010 by scientists and an artist to realise the Arusha Project which strives to implement accessible infertility programmes in resource-poor countries. Right from the start The Walking Egg has opted for a multidisciplinary and global approach towards the problem of infertility and in cooperation with the Special Task Force (STF) on "Developing countries and infertility" of the European Society of Human reproduction and Embryology (ESHRE) and the WHO, it gathers medical, social and economical scientists and experts along with artists to discuss and work together towards its goal. The project aims to raise awareness -surrounding childlessness in resource-poor countries and to make infertility care in all its aspects, including assisted reproductive technologies, available and accessible for a much larger part of the population.

  19. Faster search by lackadaisical quantum walk

    Science.gov (United States)

    Wong, Thomas G.

    2018-03-01

    In the typical model, a discrete-time coined quantum walk searching the 2D grid for a marked vertex achieves a success probability of O(1/log N) in O(√{N log N}) steps, which with amplitude amplification yields an overall runtime of O(√{N} log N). We show that making the quantum walk lackadaisical or lazy by adding a self-loop of weight 4 / N to each vertex speeds up the search, causing the success probability to reach a constant near 1 in O(√{N log N}) steps, thus yielding an O(√{log N}) improvement over the typical, loopless algorithm. This improved runtime matches the best known quantum algorithms for this search problem. Our results are based on numerical simulations since the algorithm is not an instance of the abstract search algorithm.

  20. A random walk down Main Street

    Directory of Open Access Journals (Sweden)

    David Matthew Levinson

    2016-08-01

    Full Text Available US suburbs have often been characterized by their relatively low walk accessibility compared to more urban environments, and US urban environments have been char- acterized by low walk accessibility compared to cities in other countries. Lower overall density in the suburbs implies that activities, if spread out, would have a greater distance between them. But why should activities be spread out instead of developed contiguously? This brief research note builds a positive model for the emergence of contiguous development along “Main Street” to illustrate the trade-offs that result in the built environment we observe. It then suggests some policy interventions to place a “thumb on the scale” to choose which parcels will develop in which sequence to achieve socially preferred outcomes.

  1. Abstract Interpretation and Attribute Gramars

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    The objective of this thesis is to explore the connections between abstract interpretation and attribute grammars as frameworks in program analysis. Abstract interpretation is a semantics-based program analysis method. A large class of data flow analysis problems can be expressed as non-standard ......The objective of this thesis is to explore the connections between abstract interpretation and attribute grammars as frameworks in program analysis. Abstract interpretation is a semantics-based program analysis method. A large class of data flow analysis problems can be expressed as non......-standard semantics where the ``meaning'' contains information about the runtime behaviour of programs. In an abstract interpretation the analysis is proved correct by relating it to the usual semantics for the language. Attribute grammars provide a method and notation to specify code generation and program analysis...

  2. A Short Walk along the Gravimeters Path

    Directory of Open Access Journals (Sweden)

    Iginio Marson

    2012-01-01

    Full Text Available The history of gravity measurements begun in 1604 with Galileo Galilei experiments on the acceleration due to the gravity force of the earth, g, along inclined planes. In his memory, the most used unit to measure g is the gal (10−2 m/s2. The paper takes the interested reader through a walk along some of the most important achievements in gravity measurements and gives some perspectives for future developments in terrestrial gravity.

  3. Dynamic random walks theory and applications

    CERN Document Server

    Guillotin-Plantard, Nadine

    2006-01-01

    The aim of this book is to report on the progress realized in probability theory in the field of dynamic random walks and to present applications in computer science, mathematical physics and finance. Each chapter contains didactical material as well as more advanced technical sections. Few appendices will help refreshing memories (if necessary!).· New probabilistic model, new results in probability theory· Original applications in computer science· Applications in mathematical physics· Applications in finance

  4. Random-walk model of precompound decay

    International Nuclear Information System (INIS)

    Akkermans, J.M.; Gruppelaar, H.

    1981-01-01

    It is demonstrated that the dynamics of precompound nuclear decay can be formulated, with regard to emission spectra as well as angular distributions, in terms of a simple random walk of the composite nuclear system. In distinction to other preequilibrium models a discrete time parameter is introduced, corresponding to the number of intranuclear interactions. This random-walk description can be employed to analytically calculate several characteristics of the equilibration process, such as the mean time to emission from an exciton state, the mean first passage time, and the attainment of isotropy. Also a simple and compact description of multi-particle emission is obtained. A necessary and sufficient condition is given for the equivalence of the random-walk and the usual exciton models. As an application some neutron emission spectra of neutron-induced reactions on 127 I at E = 15 to 50 MeV have been calculated. The results show that preequilibrium effects are very important in the first particle emission. In the emission of secondary particles preequilibrium effects need to be included at incoming energies above about 25 MeV. Preequilibrium effects in tertiary emission spectra are not significant below E = 50 MeV. (orig.)

  5. Gait Recognition and Walking Exercise Intensity Estimation

    Directory of Open Access Journals (Sweden)

    Bor-Shing Lin

    2014-04-01

    Full Text Available Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients’ exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, αβ filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD was used to filter the noise of patients’ attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study.

  6. Random Walks on Homeo( S 1)

    Science.gov (United States)

    Malicet, Dominique

    2017-12-01

    In this paper, we study random walks {g_n=f_{n-1}\\ldots f_0} on the group Homeo ( S 1) of the homeomorphisms of the circle, where the homeomorphisms f k are chosen randomly, independently, with respect to a same probability measure {ν}. We prove that under the only condition that there is no probability measure invariant by {ν}-almost every homeomorphism, the random walk almost surely contracts small intervals. It generalizes what has been known on this subject until now, since various conditions on {ν} were imposed in order to get the phenomenon of contractions. Moreover, we obtain the surprising fact that the rate of contraction is exponential, even in the lack of assumptions of smoothness on the f k 's. We deduce various dynamical consequences on the random walk ( g n ): finiteness of ergodic stationary measures, distribution of the trajectories, asymptotic law of the evaluations, etc. The proof of the main result is based on a modification of the Ávila-Viana's invariance principle, working for continuous cocycles on a space fibred in circles.

  7. Random walks on generalized Koch networks

    International Nuclear Information System (INIS)

    Sun, Weigang

    2013-01-01

    For deterministically growing networks, it is a theoretical challenge to determine the topological properties and dynamical processes. In this paper, we study random walks on generalized Koch networks with features that include an initial state that is a globally connected network to r nodes. In each step, every existing node produces m complete graphs. We then obtain the analytical expressions for first passage time (FPT), average return time (ART), i.e. the average of FPTs for random walks from node i to return to the starting point i for the first time, and average sending time (AST), defined as the average of FPTs from a hub node to all other nodes, excluding the hub itself with regard to network parameters m and r. For this family of Koch networks, the ART of the new emerging nodes is identical and increases with the parameters m or r. In addition, the AST of our networks grows with network size N as N ln N and also increases with parameter m. The results obtained in this paper are the generalizations of random walks for the original Koch network. (paper)

  8. The Walk-Man Robot Software Architecture

    Directory of Open Access Journals (Sweden)

    Mirko Ferrati

    2016-05-01

    Full Text Available A software and control architecture for a humanoid robot is a complex and large project, which involves a team of developers/researchers to be coordinated and requires many hard design choices. If such project has to be done in a very limited time, i.e., less than 1 year, more constraints are added and concepts, such as modular design, code reusability, and API definition, need to be used as much as possible. In this work, we describe the software architecture developed for Walk-Man, a robot participant at the Darpa Robotics Challenge. The challenge required the robot to execute many different tasks, such as walking, driving a car, and manipulating objects. These tasks need to be solved by robotics specialists in their corresponding research field, such as humanoid walking, motion planning, or object manipulation. The proposed architecture was developed in 10 months, provided boilerplate code for most of the functionalities required to control a humanoid robot and allowed robotics researchers to produce their control modules for DRC tasks in a short time. Additional capabilities of the architecture include firmware and hardware management, mixing of different middlewares, unreliable network management, and operator control station GUI. All the source code related to the architecture and some control modules have been released as open source projects.

  9. Visual evoked responses during standing and walking

    Directory of Open Access Journals (Sweden)

    Klaus Gramann

    2010-10-01

    Full Text Available Human cognition has been shaped both by our body structure and by its complex interactionswith its environment. Our cognition is thus inextricably linked to our own and others’ motorbehavior. To model brain activity associated with natural cognition, we propose recording theconcurrent brain dynamics and body movements of human subjects performing normal actions.Here we tested the feasibility of such a mobile brain/body (MoBI imaging approach byrecording high-density electroencephalographic (EEG activity and body movements of subjectsstanding or walking on a treadmill while performing a visual oddball response task. Independentcomponent analysis (ICA of the EEG data revealed visual event-related potentials (ERPs thatduring standing, slow walking, and fast walking did not differ across movement conditions,demonstrating the viability of recording brain activity accompanying cognitive processes duringwhole body movement. Non-invasive and relatively low-cost MoBI studies of normal, motivatedactions might improve understanding of interactions between brain and body dynamics leadingto more complete biological models of cognition.

  10. Does external walking environment affect gait patterns?

    Science.gov (United States)

    Patterson, Matthew R; Whelan, Darragh; Reginatto, Brenda; Caprani, Niamh; Walsh, Lorcan; Smeaton, Alan F; Inomata, Akihiro; Caulfield, Brian

    2014-01-01

    The objective of this work is to develop an understanding of the relationship between mobility metrics obtained outside of the clinic or laboratory and the context of the external environment. Ten subjects walked with an inertial sensor on each shank and a wearable camera around their neck. They were taken on a thirty minute walk in which they mobilized over the following conditions; normal path, busy hallway, rough ground, blind folded and on a hill. Stride time, stride time variability, stance time and peak shank rotation rate during swing were calculated using previously published algorithms. Stride time was significantly different between several of the conditions. Technological advances mean that gait variables can now be captured as patients go about their daily lives. The results of this study show that the external environment has a significant impact on the quality of gait metrics. Thus, context of external walking environment is an important consideration when analyzing ambulatory gait metrics from the unsupervised home and community setting.

  11. Treadmill walking of the pneumatic biped Lucy: Walking at different speeds and step-lengths

    Science.gov (United States)

    Vanderborght, B.; Verrelst, B.; Van Ham, R.; Van Damme, M.; Versluys, R.; Lefeber, D.

    2008-07-01

    Actuators with adaptable compliance are gaining interest in the field of legged robotics due to their capability to store motion energy and to exploit the natural dynamics of the system to reduce energy consumption while walking and running. To perform research on compliant actuators we have built the planar biped Lucy. The robot has six actuated joints, the ankle, knee and hip of both legs with each joint powered by two pleated pneumatic artificial muscles in an antagonistic setup. This makes it possible to control both the torque and the stiffness of the joint. Such compliant actuators are used in passive walkers to overcome friction when walking over level ground and to improve stability. Typically, this kind of robots is only designed to walk with a constant walking speed and step-length, determined by the mechanical design of the mechanism and the properties of the ground. In this paper, we show that by an appropriate control, the robot Lucy is able to walk at different speeds and step-lengths and that adding and releasing weights does not affect the stability of the robot. To perform these experiments, an automated treadmill was built

  12. Community walking can be assessed using a 10-metre timed walk test.

    Science.gov (United States)

    Kempen, J C E; de Groot, V; Knol, D L; Polman, C H; Lankhorst, G J; Beckerman, H

    2011-08-01

    A decline in mobility is a common feature of multiple sclerosis (MS). Community walking scales are used to categorize patients in their ability to move independently. The first purpose of this study was to determine which specific gait speed corresponded with the categories of the Modified Functional Walking Categories (MFWC). The second purpose was to determine the Minimally Important Change (MIC) in absolute gait speed using the MFWC and Expanded Disability Status Scale (EDSS) as external criteria. MS patients were measured six times in 6 years. Gait velocity was measured with the 10-metre timed walk test (10-m TWT), the severity of MS was determined with the EDSS, and community walking was assessed with the MFWC. For each category of the MFWC, Receiver Operating Characteristic (ROC) curves were used to find the best possible cut-off point on the 10-m TWT. The MIC in absolute gait speed was determined using a change of one category on the MFWC or one point on the EDSS. A strong relationship was found between gait speed and the MFWC; all areas under the ROC curves (AUCs) were between 0.74 and 0.86. The MIC in absolute gait speed could not be determined, because the AUCs were below the threshold of 0.70 and changes in gait speed were small. Gait speed is related to community walking, but an MIC in absolute gait speed could not be determined using a minimally important change on the MFWC or the EDSS as external criteria.

  13. [Determining factors of walking distance during 6-minutes walk test in COPD patients].

    Science.gov (United States)

    Bruyneel, M; Jacob, V; Sanida, C; Ferrali, O; Ameye, L; Ninane, V; Sergysels, R

    2012-11-01

    In stable COPD, we studied the factors determining six-minute walking distance and dyspnea at the end of the test. Patients were evaluated by tests of lung function, St Georges' respiratory questionnaire (SGRQ) and 6MWT with inspiratory capacity measurements (IC) and continuous oxymetry. Eighty-two patients (mean FEV(1): 56+19% predicted) were studied. Mean 6-minute walking distance was 477+89m, (72+14% PV). Walking distance during 6MWT (m) was correlated with FEV(1), IC/TLC ratio, TLC, pre-test IC and DLco/VA. When expressed as a percent of predicted values, walking distance was correlated with FRC, pre-test IC and SGRQ activity score. End-test dyspnea was correlated with FRC, pre-test dyspnea and SGRQ activity and total scores. The factors determining 6-minute walking distance and end-test dyspnea are complex and include both functional and non-functional factors. In COPD, 6MWT is thus an investigation that has additional integrative value. Copyright © 2012 SPLF. Published by Elsevier Masson SAS. All rights reserved.

  14. The shuttle walk test: a new approach to functional walking capacity measurements for patients after stroke?

    Science.gov (United States)

    van Bloemendaal, Maijke; Kokkeler, Astrid M; van de Port, Ingrid G

    2012-01-01

    To determine the construct validity, test-retest reliability, and measurement error of the shuttle walk test (SWT) for patients after stroke. Clinimetric study. Three rehabilitation centers in the Netherlands. A sample of patients after stroke (N=75; mean age ± SD, 58.8±9.8y) who are capable of walking without physical assistance. Patients were excluded if they had sustained a subarachnoid hemorrhage or a stroke in the cerebellum or brainstem, or had any other conditions that limited their walking capacity more than the current stroke, or had sensory aphasia. Not applicable. Construct validity (6-minute walk test [6MWT]) and test-retest reliability of the SWT were assessed. Measurement error was determined with the standard error of measurement (SEM), limits of agreement, and smallest detectable differences (SDDs). Construct validity was confirmed by high significant correlations (r(p)≥.65, Pwalking distance in favor of the 6MWT. Test-retest reliability was good (intraclass correlation coefficient model 2,1 [ICC(2,1)]=.961 [.936-.977]). SEM was 6.0%, and the SDDs for individual and group were 302.0m (37%) and 38.7m (5%), respectively. The SWT is a valid and reliable measure and therefore a feasible instrument to determine functional walking capacity of patients after stroke, especially in high-speed walkers. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  15. 'It was not just a walking experience': reflections on the role of care in dog-walking.

    Science.gov (United States)

    Degeling, Chris; Rock, Melanie

    2013-09-01

    Research into physical activity and human health has recently begun to attend to dog-walking. This study extends the literature on dog-walking as a health behaviour by conceptualizing dog-walking as a caring practice. It centres on qualitative interviews with 11 Canadian dog-owners. All participants resided in urban neighbourhoods identified through previous quantitative research as conducive to dog-walking. Canine characteristics, including breed and age, were found to influence people's physical activity. The health of the dog and its position in the life-course influenced patterns of dog-walking. Frequency, duration and spatial patterns of dog-walking all depended on relationships and people's capacity to tap into resources. In foregrounding networks of care, inclusive of pets and public spaces, a relational conceptualization of dog-walking as a practice of caring helps to make sense of heterogeneity in patterns of physical activity among dog-owners.

  16. Numerical Simulations of Level-Ground Walking Based on Passive Walk for Planar Biped Robots with Torso by Hip Actuators

    Science.gov (United States)

    Narukawa, Terumasa; Takahashi, Masaki; Yoshida, Kazuo

    This study aims at a design technique of energy-efficient biped walking robots on level ground with simple mechanisms. To do this, we focus on the passive dynamic walkers which can walk stably down a shallow slope without actuators and controllers. On level ground, active walking should be studied because the mechanical energy is mainly lost through the swing-leg impacts with the ground. In this paper, numerical simulations show that planar biped robots with torso can walk efficiently on level ground over a wide range of speed by only using hip actuators. The hip actuators are used for a torso and swing-leg control based on passive-dynamic walking. The torso is used to generate active power replacing gravity used in the case of the passive walk. The swing-leg control is introduced to walk stably over a wide range of speed.

  17. Validity of the shuttle walk test as a functional assessment of walking ability in individuals with polyneuropathy.

    Science.gov (United States)

    Erdmann, Peter G; Teunissen, Laurien L; van den Berg, Leonard H; Notermans, Nicolette C; Schröder, Carin D; Bongers, Bart C; van Meeteren, Nico L U

    2017-10-01

    This study assessed the validity of the shuttle walk test (SWT) to evaluate walking ability in patients with polyneuropathy. Forty-one patients with chronic idiopathic axonal polyneuropathy (CIAP) and 49 patients with multifocal motor neuropathy (MMN) performed both the 10-meter walk test (10MWT) and the SWT. Face validity was assessed by evaluating whether patients considered both tests to reflect their walking ability (Likert scale: 1 = not at all, 10 = very well). Concurrent validity was determined by Spearman rank-correlation analyses performed on the outcomes of both tests. Mean (SD) scores for how well the 10MWT and SWT reflected daily walking ability were 6.8 (1.3) and 7.4 (1.6) (p = 0.117) in patients with CIAP and 6.9 (1.2) and 7.9 (1.0) (p = 0.001) in patients with MMN, respectively. Correlation scores between both tests ranged from -0.70 to -0.82, except for 18 patients with MMN with a "normal" walking speed at the 10MWT (-0.21). The SWT seems a valid instrument for assessing walking ability in individuals with CIAP and MMN. Moreover, the SWT seems to be useful for investigating the symptoms elicited by walking long distances and may be more sensitive to changes when compared to the 10MWT. Implications for Rehabilitation Patients with polyneuropathy mainly experience problems when walking long distances. The 10-meter walk test does not possess sufficient psychometrics to diagnose walking abilities in these circumstances. The shuttle walk test is a valid instrument for assessing walking ability in individuals with polyneuropathy and might be the preferred instrument of choice when compared to the 10-meter walk test.

  18. Effects of Intermittent Versus Continuous Walking on Distance Walked and Fatigue in Persons With Multiple Sclerosis: A Randomized Crossover Trial.

    Science.gov (United States)

    Karpatkin, Herb; Cohen, Evan T; Rzetelny, Adam; Parrott, J Scott; Breismeister, Breanne; Hartman, Ryan; Luu, Ronald; Napolione, Danielle

    2015-07-01

    Fatigue is a common, disabling symptom experienced by persons with multiple sclerosis (MS). Evidence shows that intermittent exercise is associated in improved performance and negligible fatigue. The purpose of this study was to examine whether subjects with MS walk greater distances with less fatigue under intermittent (INT) or continuous (CONT) walking condition. Twenty-seven subjects with MS (median Extended Disability Severity Scale 3.5, interquartile range 1.6) walked in the CONT (ie, 6 uninterrupted minutes) and INT (ie, three 2-minute walking bouts) conditions in a randomized crossover. Distance was measured for the entire 6-minute walking period and each 2-minute increment. Fatigue was measured as the difference in a visual analog scale of fatigue (ΔVAS-F) immediately preceding and following each trial. Participants walked greater distances in the INT condition compared to the CONT condition (P = 0.005). There was a significant interaction of walking condition and time (P walked in the INT condition changed across time. ΔVAS-F was significantly lower in the INT condition than in the CONT condition (P = 0.036). Subjects with MS walked farther, and with less fatigue, when walking intermittently rather than continuously. Persons with MS may be able to tolerate a greater dose of walking training if the walking bouts are intermittent. Further study to determine the benefits of a walking exercise program using intermittent walking is recommended.Video Abstract available for additional insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A103).

  19. A walking program for nursing home residents: effects on walk endurance, physical activity, mobility, and quality of life.

    Science.gov (United States)

    MacRae, P G; Asplund, L A; Schnelle, J F; Ouslander, J G; Abrahamse, A; Morris, C

    1996-02-01

    To determine the effects of a 12-week walking program on walk endurance capacity, physical activity level, mobility, and quality of life in ambulatory nursing home residents who had been identified as having low physical activity levels and low walk endurance capacities. To determine the effects of 12 versus 22 weeks of walk training on walk endurance capacity, physical activity level, mobility, and quality of life in ambulatory nursing home residents. Experiment 1: Residents of one nursing home campus were assigned to the walking program, and residents of a second campus were assigned to the social visit control group. Outcome measures were taken before and after 12 weeks. Experiment 2: Pretest/posttest with outcome measures taken before and, again, after 12 and 22 weeks of walking. Two campuses of the Jewish Homes for the Aging in the Los Angeles area. Experiment 1: Nineteen of 22 residents in the walking group completed the walking program, and 12 of 15 residents in the control group completed the study. Experiment 2: Thirty of 41 residents (from the two nursing homes) completed the 22-week walking program. Experiment 1: The walking program involved each resident walking with research staff at his/her self-selected walking pace, 5 days per week for 12 weeks, for a maximum of 30 minutes per day; while the control group had weekly individual social visits, which lasted 30 minutes, from a research assistant. Experiment 2: All residents, those in both the walking and the control group, were offered the opportunity to complete 22 weeks of walking. Maximal walk endurance capacity, the resident's maximum walk time performed in a single day of walking (distance and speed also were measured); physical activity level based on time-sampled observations and physical activity monitors; mobility as measured with the Timed-Up-and-Go test, left handgrip strength, and Tinetti's Mobility Assessment; and quality of life as assessed with the Geriatric Depression Scale (a bodily

  20. Using intelligent controller to enhance the walking stability of bipedal walking robot

    Science.gov (United States)

    Hsieh, Tsung-Che; Chang, Chia-Der

    2016-07-01

    This paper is to improve the stability issue of the bipedal walking robot. The study of robot's pivot joint constructs the driver system to control the implementation. First, a Proportion-Integral-Derivative (PID) controller is designed by which is used the concept of tuning parameter to achieve the stability of the system. Second, Fuzzy controller and tradition PID controller is used to maintain output. It improved original PID controller efficacy. Finally, Artificial Neuro-Fuzzy Inference System (ANFIS) is utilized which is made the controller to achieve self-studying and modify the effect which is completed by the intelligent controller. It improved bipedal robot's stability control of realization. The result is verified that the walking stability of the bipedal walking robot in Matlab/Simulink. The intelligent controller has achieved the desired position of motor joint and the target stability performance.

  1. Maximal-entropy random walk unifies centrality measures.

    Science.gov (United States)

    Ochab, J K

    2012-12-01

    This paper compares a number of centrality measures and several (dis-)similarity matrices with which they can be defined. These matrices, which are used among others in community detection methods, represent quantities connected to enumeration of paths on a graph and to random walks. Relationships between some of these matrices are derived in the paper. These relationships are inherited by the centrality measures. They include measures based on the principal eigenvector of the adjacency matrix, path enumeration, as well as on the stationary state, stochastic matrix, or mean first-passage times of a random walk. As the random walk defining the centrality measure can be arbitrarily chosen, we pay particular attention to the maximal-entropy random walk, which serves as a very distinct alternative to the ordinary (diffusive) random walk used in network analysis. The various importance measures, defined both with the use of ordinary random walk and the maximal-entropy random walk, are compared numerically on a set of benchmark graphs with varying mixing parameter and are grouped with the use of the agglomerative clustering technique. It is shown that centrality measures defined with the two different random walks cluster into two separate groups. In particular, the group of centrality measures defined by the maximal-entropy random walk does not cluster with any other measures on change of graphs' parameters, and members of this group produce mutually closer results than members of the group defined by the ordinary random walk.

  2. Neuromechanical adaptations during a robotic powered exoskeleton assisted walking session.

    Science.gov (United States)

    Ramanujam, Arvind; Cirnigliaro, Christopher M; Garbarini, Erica; Asselin, Pierre; Pilkar, Rakesh; Forrest, Gail F

    2017-04-20

    To evaluate gait parameters and neuromuscular profiles of exoskeleton-assisted walking under Max Assist condition during a single-session for; (i) able bodied (AB) individuals walking assisted with (EXO) and without (non-EXO) a powered exoskeleton, (ii) non-ambulatory SCI individuals walking assisted with a powered exoskeleton. Single-session. Motion analysis laboratory. Four AB individuals and four individuals with SCI. Powered lower extremity exoskeleton. Temporal-spatial parameters, kinematics, walking velocity and electromyography data. AB individuals in exoskeleton showed greater stance time and a significant reduction in walking velocity (P exoskeleton movements, they walked with an increased velocity and lowered stance time to resemble that of slow walking. For SCI individuals, mean percent stance time was higher and walking velocity was lower compared to all AB walking conditions (P exoskeleton and moreover with voluntary control there is a greater temporal-spatial response of the lower limbs. Also, there are neuromuscular phasic adaptions for both AB and SCI groups while walking in the exoskeleton that are inconsistent to non-EXO gait muscle activation.

  3. Can environmental improvement change the population distribution of walking?

    Science.gov (United States)

    Panter, Jenna; Ogilvie, David

    2017-06-01

    Few studies have explored the impact of environmental change on walking using controlled comparisons. Even fewer have examined whose behaviour changes and how. In a natural experimental study of new walking and cycling infrastructure, we explored changes in walking, identified groups who changed in similar ways and assessed whether exposure to the infrastructure was associated with trajectories of walking. 1257 adults completed annual surveys assessing walking, sociodemographic and health characteristics and use of the infrastructure (2010-2012). Residential proximity to the new routes was assessed objectively. We used latent growth curve models to assess change in total walking, walking for recreation and for transport, used simple descriptive analysis and latent class analysis (LCA) to identify groups who changed in similar ways and examined factors associated with group membership using multinomial regression. LCA identified five trajectories, characterised by consistently low levels; consistently high levels; decreases; short-lived increases; and sustained increases. Those with lower levels of education and lower incomes were more likely to show both short-lived and sustained increases in walking for transport. However, those with lower levels of education were less likely to take up walking. Proximity to the intervention was associated with both uptake of and short-lived increases in walking for transport. Environmental improvement encouraged the less active to take up walking for transport, as well as encouraging those who were already active to walk more. Further research should disentangle the role of socioeconomic characteristics in determining use of new environments and changes in walking. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  4. Temporal dynamics of recurrent airway symptoms and cellular random walk.

    Science.gov (United States)

    Suki, Béla; Frey, Urs

    2003-11-01

    Asthma is a complex chronic inflammatory disease of the small airways that has dramatically increased in prevalence in industrialized countries during the last decades. Risk factors for adult asthma have been related to the complex array of gene-environment interactions and exposure of the immune system to allergens in early childhood. In genetically predisposed subjects, continuous exposure to environmental agents such as allergens or infections can lead to recurrent airway symptoms characterized by recurrent episodes of airway inflammation and bronchoconstriction with clinical symptoms of cough, dyspnea, or wheezing. In this study, we report that the longterm temporal dynamics of recurrent airway symptoms in a population of unselected infants display a complex intermittent pattern and that the distribution of interepisode intervals follows a power law. We interpret the data by using a model of the dynamics of attack episodes in which an attack is triggered by an avalanche of airway constrictions. We map the dynamics of this model to the known problem of a random walk in the presence of an absorbing boundary in which the walker corresponds to the fluctuations in contractile state of airway smooth muscle cells. These findings may provide new insight into the mechanisms of otherwise unexplained symptom episodes.

  5. Tandem walking as a quick screening test for vestibular disorders.

    Science.gov (United States)

    Cohen, Helen S; Stitz, Jasmine; Sangi-Haghpeykar, Haleh; Williams, Susan P; Mulavara, Ajitkumar P; Peters, Brian T; Bloomberg, Jacob J

    2017-12-11

    Although many screening tests of balance are available, few of them have been well validated for clinical or research uses. The goal of this study was to test an updated version of an old test, Tandem Walking, to determine how useful it is for screening patients with vestibular disorders. Case-control study. Subjects were 90 adult patients with vestibular disorders and 292 healthy adult controls. They were tested on the number of correct tandem steps they could perform with arms crossed and eyes closed in a series of 10 steps. Correct steps could be nonconsecutive. Subjects were given one practice trial with eyes open and three experimental trials with eyes closed. Receiver operating characteristic (ROC), and sensitivity and specificity were calculated. ROC values, sensitivity, and specificity were, at best, only moderate, no matter how the age range was cut. Even for subjects in the age group with the highest ROC value (i.e., age less than 50 years), ROC = 0.8, sensitivity = 0.77, and specificity = 0.72. These results indicate that 23% of patients will not be identified. Therefore, we recommend that if this test is used for screening patients in the clinic or healthy volunteers, the result should be interpreted with care. 3b Laryngoscope, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  6. Broiler walking ability and toe asymmetry under harsh rearing conditions

    Directory of Open Access Journals (Sweden)

    MS Baracho

    2012-09-01

    Full Text Available Morphological asymmetry has been described as a potential broiler welfare indicator, for interpreting the birds' ability to cope with the challenges that may affect its growth. The objective of this study was to evaluate the use of morphological asymmetry data to estimate broiler walking ability and welfare.dBroilers werefed diets supplemented or not with vitamin D. Toes were measured when birds were 42 and 49 days old using digital caliper.the left and right sides of the following four bilateral traits (tarsometatarsus length, outer toe length, mid toe length, and back toe length were measured twice on intact alive birds by two different researcherh. Data from right and left sides were compared in the two treatments using the Student t-test, and Pearson's correlation was used to analyze the total asymmetry found as a result of the total sum of the differences in the measurements. Asymmetry data were comparedwith the total numberof leg lesions. Mid toe and tarsometatarsus asymmetry resultswere considered as actual fluctuating asymmetry, and presented normal distribution (Test of Kolmogorov-Smirnov, p >0.05. However, back toe and outer toe measurements were not normally distributed, as determined by the test of Kolmogorov-Smirnov (p <0.05, indicating anti-asymmetry; when comparing right with left limb,results were significantly different fron zero (t-Student, p <0.05 indicating directional fluctuating asymmetry.The welfare of broilers withwalking difficulty due to the presence of severe asymmetry in limbs is poor.

  7. Walking for Well-Being: Are Group Walks in Certain Types of Natural Environments Better for Well-Being than Group Walks in Urban Environments?

    Directory of Open Access Journals (Sweden)

    Sara L. Warber

    2013-10-01

    Full Text Available The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708 were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale, depression (Major Depressive Inventory, perceived stress (Perceived Stress Scale and emotional well-being (Positive and Negative Affect Schedule. Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through “green prescriptions” to improve psychological and emotional well-being, as well as physical activity.

  8. Walking for well-being: are group walks in certain types of natural environments better for well-being than group walks in urban environments?

    Science.gov (United States)

    Marselle, Melissa R; Irvine, Katherine N; Warber, Sara L

    2013-10-29

    The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708) were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale), depression (Major Depressive Inventory), perceived stress (Perceived Stress Scale) and emotional well-being (Positive and Negative Affect Schedule). Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through "green prescriptions" to improve psychological and emotional well-being, as well as physical activity.

  9. Interpreting Sustainability for Urban Forests

    Directory of Open Access Journals (Sweden)

    Camilo Ordóñez

    2010-06-01

    Full Text Available Incisive interpretations of urban-forest sustainability are important in furthering our understanding of how to sustain the myriad values associated with urban forests. Our analysis of earlier interpretations reveals conceptual gaps. These interpretations are attached to restrictive definitions of a sustainable urban forest and limited to a rather mechanical view of maintaining the biophysical structure of trees. The probing of three conceptual domains (urban forest concepts, sustainable development, and sustainable forest management leads to a broader interpretation of urban-forest sustainability as the process of sustaining urban forest values through time and across space. We propose that values—and not services, benefits, functions or goods—is a superior concept to refer to what is to be sustained in and by an urban forest.

  10. Federal Aviation Administration Legal Interpretations

    Data.gov (United States)

    Department of Transportation — Legal Interpretations and the Chief Counsel's opinions are now available at this site. Your may choose to search by year or by text search. Please note that not all...

  11. COURT INTERPRETING AT DENPASAR COURT

    Directory of Open Access Journals (Sweden)

    Ida Ayu Made Puspani

    2012-11-01

    Full Text Available This is a research on interpreting (oral translation on a criminal case ofdrug user in the court proceedings at Denpasar Court. The study of theinterpreting is concerned with two-ways rendition from Indonesian into Englishand vice-versa. The study is related to: (1 the description of modes of interpretingapplied by the interpreter, (2 the application of translation strategies: shift,addition and deletion of information, (3 factors that underlie the application ofthe strategies, and (4 the impact of the application of those strategies towards thequality of the interpreting.The methodology applied in this study is qualitative based on eclectictheories (translation, syntax, semantics and pragmatics. The utilization of thetheories is in accordance with the type of the data analyzed in regard to thetranslation phenomena as an applied study and its complexity.The interpreting at court applied the consecutive and simultaneous modes.The strategy of shift was applied when there were differences in structure betweenthe source and the target languages. Addition of information was used when theinterpreter emphasized the message of the source language in the target language.The deletion of information applied if the context in the target language has beencovered, and it was not necessary for the interpreter to interpret the same thingbecause the message of the source language was pragmatically implied in thetarget language.The factors which underlie the application of the interpreting strategies incourt interpreting were communication factor and the differences in the languagesystems between the source and the target languages. The impact of the use of thestrategies towards the quality of the interpreting happened when the interpretationof the source language message into the message of the target language and themessage in the source language was not completely render into the targetlanguage.The novelties of the research are: (1 relevance theory and its

  12. Walk Score, Transportation Mode Choice, and Walking Among French Adults: A GPS, Accelerometer, and Mobility Survey Study.

    Science.gov (United States)

    Duncan, Dustin T; Méline, Julie; Kestens, Yan; Day, Kristen; Elbel, Brian; Trasande, Leonardo; Chaix, Basile

    2016-06-20

    Few studies have used GPS data to analyze the relationship between Walk Score, transportation choice and walking. Additionally, the influence of Walk Score is understudied using trips rather than individuals as statistical units. The purpose of this study is to examine associations at the trip level between Walk Score, transportation mode choice, and walking among Paris adults who were tracked with GPS receivers and accelerometers in the RECORD GPS Study. In the RECORD GPS Study, 227 participants were tracked during seven days with GPS receivers and accelerometers. Participants were also surveyed with a GPS-based web mapping application on their activities and transportation modes for all trips (6969 trips). Walk Score, which calculates neighborhood walkability, was assessed for each origin and destination of every trip. Multilevel logistic and linear regression analyses were conducted to estimate associations between Walk Score and walking in the trip or accelerometry-assessed number of steps for each trip, after adjustment for individual/neighborhood characteristics. The mean overall Walk Scores for trip origins were 87.1 (SD = 14.4) and for trip destinations 87.1 (SD = 14.5). In adjusted trip-level associations between Walk Score and walking only in the trip, we found that a walkable neighborhood in the trip origin and trip destination was associated with increased odds of walking in the trip assessed in the survey. The odds of only walking in the trip were 3.48 (95% CI: 2.73 to 4.44) times higher when the Walk Score for the trip origin was "Walker's Paradise" compared to less walkable neighborhoods (Very/Car-Dependent or Somewhat Walkable), with an identical independent effect of trip destination Walk Score on walking. The number of steps per 10 min (as assessed with accelerometry) was cumulatively higher for trips both originating and ending in walkable neighborhoods (i.e., "Very Walkable"). Walkable neighborhoods were associated with increases in walking

  13. Interpretation of macroscopic quantum phenomena

    International Nuclear Information System (INIS)

    Baumann, K.

    1986-01-01

    It is argued that a quantum theory without observer is required for the interpretation of macroscopic quantum tunnelling. Such a theory is obtained by augmenting QED by the actual electric field in the rest system of the universe. An equation of the motion of this field is formulated form which the correct macroscopic behavior of the universe and the validity of the Born interpretation is derived. Care is taken to use mathematically sound concepts only. (Author)

  14. Resistance to change: Four interpretations

    OpenAIRE

    Bringselius, Louise

    2010-01-01

    Although the phenomenon of resistance to change has gained considerable attention in organization theory over the years, the meaning of the concept is rarely discussed. In this paper, a conceptual framework is suggested that distinguishes between four interpretations of resistance and builds upon the two variables of changeability and emotionality. Each interpretation is based on various assumptions and theoretical influences, as well as connected to different change management strategies. Th...

  15. Court interpreting and pragmatic meaning

    DEFF Research Database (Denmark)

    Jacobsen, Bente

    In Denmark, court interpreters are required to deliver verbatim translations of speakers' originals and to refrain from transferring pragmatic meaning. Yet, as this paper demonstrates, pragmatic meaning is central to courtroom interaction.......In Denmark, court interpreters are required to deliver verbatim translations of speakers' originals and to refrain from transferring pragmatic meaning. Yet, as this paper demonstrates, pragmatic meaning is central to courtroom interaction....

  16. Daily intermittent hypoxia enhances walking after chronic spinal cord injury

    Science.gov (United States)

    Hayes, Heather B.; Jayaraman, Arun; Herrmann, Megan; Mitchell, Gordon S.; Rymer, William Z.

    2014-01-01

    Objectives: To test the hypothesis that daily acute intermittent hypoxia (dAIH) and dAIH combined with overground walking improve walking speed and endurance in persons with chronic incomplete spinal cord injury (iSCI). Methods: Nineteen subjects completed the randomized, double-blind, placebo-controlled, crossover study. Participants received 15, 90-second hypoxic exposures (dAIH, fraction of inspired oxygen [Fio2] = 0.09) or daily normoxia (dSHAM, Fio2 = 0.21) at 60-second normoxic intervals on 5 consecutive days; dAIH was given alone or combined with 30 minutes of overground walking 1 hour later. Walking speed and endurance were quantified using 10-Meter and 6-Minute Walk Tests. The trial is registered at ClinicalTrials.gov (NCT01272349). Results: dAIH improved walking speed and endurance. Ten-Meter Walk time improved with dAIH vs dSHAM after 1 day (mean difference [MD] 3.8 seconds, 95% confidence interval [CI] 1.1–6.5 seconds, p = 0.006) and 2 weeks (MD 3.8 seconds, 95% CI 0.9–6.7 seconds, p = 0.010). Six-Minute Walk distance increased with combined dAIH + walking vs dSHAM + walking after 5 days (MD 94.4 m, 95% CI 17.5–171.3 m, p = 0.017) and 1-week follow-up (MD 97.0 m, 95% CI 20.1–173.9 m, p = 0.014). dAIH + walking increased walking distance more than dAIH after 1 day (MD 67.7 m, 95% CI 1.3–134.1 m, p = 0.046), 5 days (MD 107.0 m, 95% CI 40.6–173.4 m, p = 0.002), and 1-week follow-up (MD 136.0 m, 95% CI 65.3–206.6 m, p walking improved walking speed and distance in persons with chronic iSCI. The impact of dAIH is enhanced by combination with walking, demonstrating that combinatorial therapies may promote greater functional benefits in persons with iSCI. Classification of evidence: This study provides Class I evidence that transient hypoxia (through measured breathing treatments), along with overground walking training, improves walking speed and endurance after iSCI. PMID:24285617

  17. Going places: Does the two-minute walk test predict the six-minute walk test in lower extremity amputees?

    Science.gov (United States)

    Reid, Lauren; Thomson, Penny; Besemann, Markus; Dudek, Nancy

    2015-03-01

    Assessing a patient's ability to walk the distance required for community ambulation (at least 300 m) is important in amputee rehabilitation. During the 2-min walk test, most amputees cannot walk 300 m. Thus, the 6-min walk test may be preferred, but it has not been fully validated in this population. This study examined the convergent and discriminative validity of the 6-min walk test and assessed whether the 2-min test could predict the results of the 6-min test. A total of 86 patients with unilateral or bilateral amputations at the Syme, transtibial, knee disarticulation or transfemoral level completed the 6-min walk test, 2-min walk test, Timed Up and Go test, Locomotor Capabilities Index version 5, Houghton Scale of Prosthetic Use, and Activity-Specific Balance Confidence scale. The 6-min walk test correlated with the other tests (R = 0.57-0.95), demonstrating convergent validity. It demonstrated discriminative validity with respect to age, aetiology of amputation, and K-level (p amputee ambulation. However, the results suggest that it may not be necessary, since the 2-min walk test strongly predicts the 6-min walk test. Clinicians could therefore save time by using the shorter test.

  18. "Four legs instead of two"--perspectives on a Nordic walking-based walking programme among people with arthritis.

    Science.gov (United States)

    O'Donovan, Rhona; Kennedy, Norelee

    2015-01-01

    Nordic Walking (NW) is growing in popularity among people with arthritis. The aim of this study was to explore the perspectives of participants with arthritis on a NW-based walking programme including factors contributing to sustained participation in the programme. Three semi-structured focus groups were conducted with a total of 27 participants with various types of arthritis. The groups consisted of participants who completed a NW-based walking programme in the previous 4 years. Only participants who had sustained involvement in the walking group were included. Groups were audio-recorded, transcribed verbatim and thematic analysis was performed. Participants reported that the walking programme offered numerous benefits. Two distinct themes emerged: (1) "four legs instead of two legs" and (2) "a support group". Theme 1 incorporates the physical, psychological and educational benefits that stem from involvement in a walking group while Theme 2 incorporates the benefits of social support in group-based activity. Several benefits of a NW-based walking programme from the perspectives of individuals with arthritis who engage in group-based walking programmes were identified. The benefits may encourage sustained participation and justify the promotion of NW as an intervention for people with arthritis. Considering how to sustain exercise participation is important to ensure continued benefits from physical activity participation. A community-based Nordic walking-based walking programme for people with arthritis improved exercise knowledge and confidence to exercise. Group exercise is valuable in providing support and motivation to continue exercising.

  19. Effects of Nordic Walking Compared to Conventional Walking and Band-Based Resistance Exercise on Fitness in Older Adults

    Science.gov (United States)

    Takeshima, Nobuo; Islam, Mohammod M.; Rogers, Michael E.; Rogers, Nicole L.; Sengoku, Naoko; Koizumi, Daisuke; Kitabayashi, Yukiko; Imai, Aiko; Naruse, Aiko

    2013-01-01

    The purpose of this study was to compare the effects of Nordic walking with conventional walking and band-based resistance exercise on functional fitness, static balance and dynamic balance in older adults. Volunteers (n = 65) were divided into four groups: Nordic walking (NW), conventional walking (CW), resistance (RES), and control. Each group performed activity 50-70 min·day−1 (warm-up 10-15 min, main exercise 30-40, and cool down 10-15 min), 3 days·week−1 (NW and CW) or 2 day·week−1 (RES) for 12 wks. Upper-body strength improved (p Cardio- respiratory fitness improved more in the NW (10.9%) and CW (10.6%) groups compared to the RES and control groups. Upper- and lower-body flexibility also improved in all exercise groups compared to the control group. There were no improvements in balance measures in any group. While all modes of exercise improved various components of fitness, Nordic walking provided the best well-rounded benefits by improving upper-body strength, cardiovascular endurance, and flexibility. Therefore, Nordic walking is recommended as an effective and efficient mode of concurrent exercise to improve overall functional fitness in older adults. Key Points Nordic walking, conventional walking, and resistance training are beneficial for older adults. Nordic walking and conventional walking both improve cardio-respiratory fitness while resistance training does not. Nordic walking provides additional benefits in upper-body muscular strength compared to conventional walking. Nordic walking is an effective and efficient mode of exercise to improve overall fitness in older adults. PMID:24149147

  20. On the physical realizability of quantum stochastic walks

    Science.gov (United States)

    Taketani, Bruno; Govia, Luke; Schuhmacher, Peter; Wilhelm, Frank

    Quantum walks are a promising framework that can be used to both understand and implement quantum information processing tasks. The recently developed quantum stochastic walk combines the concepts of a quantum walk and a classical random walk through open system evolution of a quantum system, and have been shown to have applications in as far reaching fields as artificial intelligence. However, nature puts significant constraints on the kind of open system evolutions that can be realized in a physical experiment. In this work, we discuss the restrictions on the allowed open system evolution, and the physical assumptions underpinning them. We then introduce a way to circumvent some of these restrictions, and simulate a more general quantum stochastic walk on a quantum computer, using a technique we call quantum trajectories on a quantum computer. We finally describe a circuit QED approach to implement discrete time quantum stochastic walks.