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Andrew A Biewener - One of the best experts on this subject based on the ideXlab platform.
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kinematics and power requirements of ascending and descending Flight in the pigeon columba livia
The Journal of Experimental Biology, 2008Co-Authors: Angela M Berg, Andrew A BiewenerAbstract:Ascending or descending locomotion involves a change in potential energy (PE) and a corresponding change in power requirement. We sought to test whether the mechanical power required for steady ascending or descending Flight is a simple sum of the power required for Level Flight and the power necessary for potential energy change. Pigeons (Columba livia) were trained to fly at varying angles of ascent and descent (60 degrees , 30 degrees , 0 degrees , -30 degrees , -60 degrees ), and were recorded using high-speed video. Detailed three-dimensional kinematics were obtained from the recordings, allowing analysis of wing movement. Aerodynamic forces and power requirements were then estimated from kinematic data. As expected, ;PE Flight power' increased significantly with angle of Flight (0.234 W deg.(-1)), though there appeared to be a limit on the amount of PE that the birds could gain or dissipate per wingbeat. We found that the total power output for Flight at various angles was not different from the sum of power required for Level Flight and the PE rate of change for a given angle, except for the steep -60 degrees descent. The total power for steep descent was higher than this sum because of a higher induced power due to the bird's deceleration and slower Flight velocity. Aerodynamic force estimates during mid-downstroke did not differ significantly in magnitude or orientation among Flight angles. Pigeons flew fastest during -30 degrees Flights (4.9+/-0.1 m s(-1)) and slowest at 60 degrees (2.9+/-0.1 m s(-1)). Although wingbeat frequency ranged from 6.1 to 9.6 Hz across trials, the variation was not significant across Flight angles. Stroke plane angle was more horizontal, and the wing more protracted, for both +60 degrees and -60 degrees Flights, compared with other Flight path angles.
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regional patterns of pectoralis fascicle strain in the pigeon columba livia during Level Flight
The Journal of Experimental Biology, 2005Co-Authors: Arya Soman, Tyson L Hedrick, Andrew A BiewenerAbstract:SUMMARY Regional fascicle strains were recorded in vivo from the pectoralis of carneau pigeons using sonomicrometry during Level slow Flight, together with regional electromyography (EMG) and deltopectoral crest (DPC) strain measurements of whole muscle force. Fascicle strain measurements were obtained at four sites within the pectoralis: the anterior (Ant), middle (Mid) and posterior (Post) sternobrachium (SB), and the smaller thoracobrachium (TB). Strains were also recorded along the intramuscular aponeurosis of the pectoralis to assess its `in-series9 compliance with respect to strains of Post SB and TB fascicles. In-series segment strains were also obtained along Ant SB and Mid SB fascicles, which insert directly on the DPC without attaching to the intramuscular aponeurosis. In-series segment strains differed from 2% to 17.2%, averaging differences of 6.1% at the Ant SB site and 1.4% at the Mid SB site. Temporal patterns of in-series fascicle segment strain were similar at both sites. Regional fascicle strains also exhibited similar temporal patterns of lengthening and shortening and were most uniform in magnitude at the Ant SB, Mid SB and TB sites (total strain: 33.7%, 35.9% and 33.2% respectively), but were smaller at the Post SB site (24.4%). Strains measured along the aponeurosis tracked the patterns of contractile fascicle strain but were significantly lower in magnitude (19.1%). Fascicle lengthening strains (+25.4%) greatly exceeded net shortening strains (-6.5%) at all sites. Much of the variation in regional fascicle strain patterns resulted from variation of in vivo recording sites among individual animals, despite attempts to define consistent regions for obtaining in vivo recordings. No significant variation in EMG activation onset was found, but deactivation of the Ant SB occurred before the other muscle sites. Even so, the range of variation was small, with all muscle regions being activated midway through lengthening (upstroke) and turned off midway through shortening (downstroke). While subtle differences in the timing and rate of fascicle strain may relate to differing functional roles of the pectoralis, regional patterns of fascicle strain and activation suggest a generally uniform role for the muscle as a whole throughout the wingbeat cycle. Shorter fascicles located in more posterior regions of the muscle underwent generally similar strains as longer fascicles located in more anterior SB regions. The resulting differences in fiber length were accommodated by strain in the intramuscular aponeurosis and rotation of the pectoralis insertion with respect to the origin. As a result, longer Ant and Mid SB fascicles were estimated to contribute substantially more work per unit mass than shorter Post SB and TB fascicles. When the mass fractions of these regions are accounted for, our regional fascicle strain measurements show that the anterior regions of the pectoralis likely contribute 76%, and the posterior regions 24%, of the muscle9s total work output. When adjusted for mass fraction and regional fascicle strain, pectoralis work averaged 24.7±5.1 J kg -1 (206.6±43.5 W kg -1 ) during Level slow (∼4-5 m s -1 ) Flight.
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regional patterns of pectoralis fascicle strain in the pigeon columba livia during Level Flight
The Journal of Experimental Biology, 2005Co-Authors: Arya Soman, Tyson L Hedrick, Andrew A BiewenerAbstract:Regional fascicle strains were recorded in vivo from the pectoralis of carneau pigeons using sonomicrometry during Level slow Flight, together with regional electromyography (EMG) and deltopectoral crest (DPC) strain measurements of whole muscle force. Fascicle strain measurements were obtained at four sites within the pectoralis: the anterior (Ant), middle (Mid) and posterior (Post) sternobrachium (SB), and the smaller thoracobrachium (TB). Strains were also recorded along the intramuscular aponeurosis of the pectoralis to assess its 'in-series' compliance with respect to strains of Post SB and TB fascicles. In-series segment strains were also obtained along Ant SB and Mid SB fascicles, which insert directly on the DPC without attaching to the intramuscular aponeurosis. In-series segment strains differed from 2% to 17.2%, averaging differences of 6.1% at the Ant SB site and 1.4% at the Mid SB site. Temporal patterns of in-series fascicle segment strain were similar at both sites. Regional fascicle strains also exhibited similar temporal patterns of lengthening and shortening and were most uniform in magnitude at the Ant SB, Mid SB and TB sites (total strain: 33.7%, 35.9% and 33.2% respectively), but were smaller at the Post SB site (24.4%). Strains measured along the aponeurosis tracked the patterns of contractile fascicle strain but were significantly lower in magnitude (19.1%). Fascicle lengthening strains (+25.4%) greatly exceeded net shortening strains (-6.5%) at all sites. Much of the variation in regional fascicle strain patterns resulted from variation of in vivo recording sites among individual animals, despite attempts to define consistent regions for obtaining in vivo recordings. No significant variation in EMG activation onset was found, but deactivation of the Ant SB occurred before the other muscle sites. Even so, the range of variation was small, with all muscle regions being activated midway through lengthening (upstroke) and turned off midway through shortening (downstroke). While subtle differences in the timing and rate of fascicle strain may relate to differing functional roles of the pectoralis, regional patterns of fascicle strain and activation suggest a generally uniform role for the muscle as a whole throughout the wingbeat cycle. Shorter fascicles located in more posterior regions of the muscle underwent generally similar strains as longer fascicles located in more anterior SB regions. The resulting differences in fiber length were accommodated by strain in the intramuscular aponeurosis and rotation of the pectoralis insertion with respect to the origin. As a result, longer Ant and Mid SB fascicles were estimated to contribute substantially more work per unit mass than shorter Post SB and TB fascicles. When the mass fractions of these regions are accounted for, our regional fascicle strain measurements show that the anterior regions of the pectoralis likely contribute 76%, and the posterior regions 24%, of the muscle's total work output. When adjusted for mass fraction and regional fascicle strain, pectoralis work averaged 24.7+/-5.1 J kg(-1) (206.6+/-43.5 W kg(-1)) during Level slow (approximately 4-5 m s(-1)) Flight.
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pectoralis muscle performance during ascending and slow Level Flight in mallards anas platyrhynchos
The Journal of Experimental Biology, 2001Co-Authors: Michael R Williamson, Kenneth P Dial, Andrew A BiewenerAbstract:In vivo measurements of pectoralis muscle length change and force production were obtained using sonomicrometry and delto-pectoral bone strain recordings during ascending and slow Level Flight in mallards (Anas platyrhynchos). These measurements provide a description of the force/length properties of the pectoralis under dynamic conditions during two discrete Flight behaviors and allow an examination of the effects of differences in body size and morphology on pectoralis performance by comparing the results with those of a recent similar study of slow Level Flight in pigeons (Columbia livia). In the present study, the mallard pectoralis showed a distinct pattern of active lengthening during the upstroke. This probably enhances the rate of force generation and the magnitude of the force generated and, thus, the amount of work and power produced during the downstroke. The power output of the pectoralis averaged 17.0 W kg(−)(1)body mass (131 W kg(−)(1)muscle mass) during slow Level Flight (3 m s(−)(1)) and 23.3 W kg(−)(1)body mass (174 W kg(−)(1)muscle mass) during ascending Flight. This increase in power was achieved principally via an increase in muscle strain (29 % versus 36 %), rather than an increase in peak force (107 N versus 113 N) or cycle frequency (8.4 Hz versus 8.9 Hz). Body-mass-specific power output of mallards during slow Level Flight (17.0 W kg(−)(1)), measured in terms of pectoralis mechanical power, was similar to that measured recently in pigeons (16.1 W kg(−)(1)). Mallards compensate for their greater body mass and proportionately smaller wing area and pectoralis muscle volume by operating with a high myofibrillar stress to elevate mechanical power output.
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in vivo pectoralis muscle force length behavior during Level Flight in pigeons columba livia
The Journal of Experimental Biology, 1998Co-Authors: Andrew A Biewener, W R Corning, Bret W TobalskeAbstract:For the first time, we report in vivo measurements of pectoralis muscle length change obtained using sonomicrometry combined with measurements of its force development via deltopectoral crest strain recordings of a bird in free Flight. These measurements allow us to characterize the contractile behavior and mechanical power output of the pectoralis under dynamic conditions of slow Level Flight in pigeons Columba livia. Our recordings confirm that the pigeon pectoralis generates in vivo work loops that begin with the rapid development of force as the muscle is being stretched or remains nearly isometric near the end of the upstroke. The pectoralis then shortens by a total of 32 % of its resting length during the downstroke, generating an average of 10.33.6 J kg-1 muscle (mean s.d.) of work per cycle for the anterior and posterior sites recorded among the five animals. In contrast to previous kinematic estimates of muscle length change relative to force development, the sonomicrometry measurements of fascicle length change show that force declines during muscle shortening. Simultaneous measurements of fascicle length change at anterior and posterior sites within the same muscle show significant (P<0.001, three of four animals) differences in fractional length (strain) change that averaged 1912 %, despite exhibiting similar work loop shape. Length changes at both anterior and posterior sites were nearly synchronous and had an asymmetrical pattern, with shortening occupying 63 % of the cycle. This nearly 2:1 phase ratio of shortening to lengthening probably favors the ability of the muscle to do work. Mean muscle shortening velocity was 5.381.33 and 4.881.27 lengths s-1 at the anterior and posterior sites respectively. Length excursions of the muscle were more variable at the end of the downstroke (maximum shortening), particularly when the birds landed, compared with highly uniform length excursions at the end of the upstroke (maximum lengthening). When averaged for the muscle as a whole, our in vivo work measurements yield a mass-specific net mechanical power output of 70. 2 W kg-1 for the muscle when the birds flew at 5-6 m s-1, with a wingbeat frequency of 8.7 Hz. This is 38 % greater than the value that we obtained previously for wild-type pigeons, but still 24-50 % less than that predicted by theory.
Kenneth P Dial - One of the best experts on this subject based on the ideXlab platform.
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pectoralis muscle performance during ascending and slow Level Flight in mallards anas platyrhynchos
The Journal of Experimental Biology, 2001Co-Authors: Michael R Williamson, Kenneth P Dial, Andrew A BiewenerAbstract:In vivo measurements of pectoralis muscle length change and force production were obtained using sonomicrometry and delto-pectoral bone strain recordings during ascending and slow Level Flight in mallards (Anas platyrhynchos). These measurements provide a description of the force/length properties of the pectoralis under dynamic conditions during two discrete Flight behaviors and allow an examination of the effects of differences in body size and morphology on pectoralis performance by comparing the results with those of a recent similar study of slow Level Flight in pigeons (Columbia livia). In the present study, the mallard pectoralis showed a distinct pattern of active lengthening during the upstroke. This probably enhances the rate of force generation and the magnitude of the force generated and, thus, the amount of work and power produced during the downstroke. The power output of the pectoralis averaged 17.0 W kg(−)(1)body mass (131 W kg(−)(1)muscle mass) during slow Level Flight (3 m s(−)(1)) and 23.3 W kg(−)(1)body mass (174 W kg(−)(1)muscle mass) during ascending Flight. This increase in power was achieved principally via an increase in muscle strain (29 % versus 36 %), rather than an increase in peak force (107 N versus 113 N) or cycle frequency (8.4 Hz versus 8.9 Hz). Body-mass-specific power output of mallards during slow Level Flight (17.0 W kg(−)(1)), measured in terms of pectoralis mechanical power, was similar to that measured recently in pigeons (16.1 W kg(−)(1)). Mallards compensate for their greater body mass and proportionately smaller wing area and pectoralis muscle volume by operating with a high myofibrillar stress to elevate mechanical power output.
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pectoralis muscle force and power output during different modes of Flight in pigeons columba livia
The Journal of Experimental Biology, 1993Co-Authors: Kenneth P Dial, Andrew A BiewenerAbstract:In vivo measurements of pectoralis muscle force during different modes of free Flight (takeoff, Level flapping, landing, vertical ascending and near vertical descending Flight) were obtained using a strain gauge attached to the dorsal surface of the delto-pectoral crest (DPC) of the humerus in four trained pigeons (Columba livia). In one bird, a rosette strain gauge was attached to the DPC to determine the principal axis of strain produced by tension of the pectoralis. Strain signals recorded during Flight were calibrated to force based on in situ measurements of tetanic force and on direct tension applied to the muscle9s insertion at the DPC. Rosette strain recordings showed that at maximal force the orientation of tensile principal strain was −15° (proximo-anterior) to the perpendicular axis of the DPC (or +75° to the longitudinal axis of the humerus), ranging from +15 to −25° to the DPC axis during the downstroke. The consistency of tensile principal strain orientation in the DPC confirms the more general use of single-element strain gauges as being a reliable method for determining in vivo pectoralis force generation. Our strain recordings show that the pectoralis begins to develop force as it is being lengthened, during the final one-third of the upstroke, and attains maximum force output while shortening during the first one-third of the downstroke. Force is sustained throughout the entire downstroke, even after the onset of the upstroke for certain Flight conditions. Mean peak forces developed by the pectoralis based on measurements from 40 wingbeats for each bird (160 total) were: 24.9+/−3.1 N during takeoff, 19.7+/−2.0 N during Level Flight (at speeds of about 6–9 m s-1 and a wingbeat frequency of 8.6+/−0.3 Hz), 18.7+/−2.5 N during landing, 23.7+/−2.7 N during near-vertical descent, and 26.0+/−1.8 N during vertical ascending Flight. These forces are considerably lower than the maximum isometric force (67 N, P0) of the muscle, ranging from 28 % (landing) to 39 % (vertical ascending) of P0. Based on estimates of muscle fiber length change determined from high- speed (200 frames s-1) light cine films taken of the animals, we calculate the mass-specific power output of the pigeon pectoralis to be 51 W kg-1 during Level Flight (approximately 8 m s-1), and 119 W kg-1 during takeoff from the ground. When the birds were harnessed with weighted backpacks (50 % and 100 % of body weight), the forces generated by the pectoralis did not significantly exceed those observed in unloaded birds executing vertical ascending Flight. These data suggest that the range of force production by the pectoralis under these differing conditions is constrained by the force- velocity properties of the muscle operating at fairly rapid rates of shortening (4.4 fiber lengths s-1 during Level Flight and 6.7 fiber lengths s-1 during takeoff).
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pectoralis muscle force and power output during Flight in the starling
The Journal of Experimental Biology, 1992Co-Authors: Andrew A Biewener, Kenneth P Dial, G E GoslowAbstract:Force recordings of the pectoralis muscle of European starlings have been made in vivo during Level Flight in a wind tunnel, based on bone strain recordings at the muscle9s attachment site on the humerus (deltopectoral crest). This represents the first direct measurement of muscle force during activity in a live animal based on calibrated bone strain recordings. Our force measurements confirm earlier electromyographic data and show that the pectoralis begins to develop force during the final one-third of the upstroke, reaches a maximal Level halfway through the downstroke, and sustains force throughout the downstroke. Peak forces generated by the pectoralis during Level Flight at a speed estimated to be 13.7ms −1 averaged 6.4N (28% of maximal isometric force), generating a mean mass-specific muscle power output of 104 W kg −1 . Combining our data for the power output of the pectoralis muscle with data for the metabolic power of starlings flying at a similar speed yields an overall Flight efficiency of 13 %. The force recordings and length changes of the muscle, based on angular displacements of the humerus, indicate that the pectoralis muscle undergoes a lengthening--shortening contraction sequence during its activation and that, in addition to lift and thrust generation, overcoming wing inertia is probably an important function of this muscle in flapping Flight.
Tsutomu Nagayoshi - One of the best experts on this subject based on the ideXlab platform.
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observation of diffuse cosmic and atmospheric gamma rays at balloon altitudes with an electron tracking compton camera
The Astrophysical Journal, 2011Co-Authors: A. Takada, Hironobu Nishimura, Kazuki Ueno, Shigeto Kabuki, Kentaro Miuchi, K Hattori, Eiichi Mizuta, Shunsuke Kurosawa, H. Kubo, Tsutomu NagayoshiAbstract:We observed diffuse cosmic and atmospheric gamma rays at balloon altitudes with the Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I (SMILE-I) as the first step toward a future all-sky survey with a high sensitivity. SMILE-I employed an electron-tracking Compton camera comprised of a gaseous electron tracker as a Compton-scattering target and a scintillation camera as an absorber. The balloon carrying the SMILE-I detector was launched from the Sanriku Balloon Center of the Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency on 2006 September 1, and the Flight lasted for 6.8 hr, including Level Flight for 4.1 hr at an altitude of 32-35 km. During the Level Flight, we successfully detected 420 downward gamma rays between 100 keV and 1 MeV at zenith angles below 60°. To obtain the flux of diffuse cosmic gamma rays, we first simulated their scattering in the atmosphere using Geant4, and for gamma rays detected at an atmospheric depth of 7.0 g cm–2 we found that 50% and 21% of the gamma rays at energies of 150 keV and 1 MeV, respectively, were scattered in the atmosphere prior to reaching the detector. Moreover, by using Geant4 simulations and the QinetiQ atmospheric radiation model, we estimated that the detected events consisted of diffuse cosmic and atmospheric gamma rays (79%), secondary photons produced in the instrument through the interaction between cosmic rays and materials surrounding the detector (19%), and other particles (2%). The obtained growth curve was comparable to Ling's model, and the fluxes of diffuse cosmic and atmospheric gamma rays were consistent with the results of previous experiments. The expected detection sensitivity of a future SMILE experiment measuring gamma rays between 150 keV and 20 MeV was estimated from our SMILE-I results and was found to be 10 times better than that of other experiments at around 1 MeV.
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observation of diffuse cosmic and atmospheric gamma rays at balloon altitudes with an electron tracking compton camera
arXiv: Instrumentation and Methods for Astrophysics, 2011Co-Authors: A. Takada, Hironobu Nishimura, Kazuki Ueno, Shigeto Kabuki, Kentaro Miuchi, K Hattori, Eiichi Mizuta, Shunsuke Kurosawa, H. Kubo, Tsutomu NagayoshiAbstract:We observed diffuse cosmic and atmospheric gamma rays at balloon altitudes with the Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I (SMILE-I) as the first step toward a future all-sky survey with a high sensitivity. SMILE-I employed an electron-tracking Compton camera comprised of a gaseous electron tracker as a Compton-scattering target and a scintillation camera as an absorber. The balloon carrying the SMILE-I detector was launched from the Sanriku Balloon Center of the Institute of Space and Astronomical Science/Japan Space Exploration Agency on September 1, 2006, and the Flight lasted for 6.8 hr, including Level Flight for 4.1 hr at an altitude of 32-35 km. During the Level Flight, we successfully detected 420 downward gamma rays between 100 keV and 1 MeV at zenith angles below 60 degrees. To obtain the flux of diffuse cosmic gamma rays, we first simulated their scattering in the atmosphere using Geant4, and for gamma rays detected at an atmospheric depth of 7.0 g cm-2, we found that 50% and 21% of the gamma rays at energies of 150 keV and 1 MeV, respectively, were scattered in the atmosphere prior to reaching the detector. Moreover, by using Geant4 simulations and the QinetiQ atmospheric radiation model, we estimated that the detected events consisted of diffuse cosmic and atmospheric gamma rays (79%), secondary photons produced in the instrument through the interaction between cosmic rays and materials surrounding the detector (19%), and other particles (2%). The obtained growth curve was comparable to Ling's model, and the fluxes of diffuse cosmic and atmospheric gamma rays were consistent with the results of previous experiments. The expected detection sensitivity of a future SMILE experiment measuring gamma rays between 150 keV and 20 MeV was estimated from our SMILE-I results and was found to be ten times better than that of other experiments at around 1 MeV.
A. Takada - One of the best experts on this subject based on the ideXlab platform.
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observation of diffuse cosmic and atmospheric gamma rays at balloon altitudes with an electron tracking compton camera
The Astrophysical Journal, 2011Co-Authors: A. Takada, Hironobu Nishimura, Kazuki Ueno, Shigeto Kabuki, Kentaro Miuchi, K Hattori, Eiichi Mizuta, Shunsuke Kurosawa, H. Kubo, Tsutomu NagayoshiAbstract:We observed diffuse cosmic and atmospheric gamma rays at balloon altitudes with the Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I (SMILE-I) as the first step toward a future all-sky survey with a high sensitivity. SMILE-I employed an electron-tracking Compton camera comprised of a gaseous electron tracker as a Compton-scattering target and a scintillation camera as an absorber. The balloon carrying the SMILE-I detector was launched from the Sanriku Balloon Center of the Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency on 2006 September 1, and the Flight lasted for 6.8 hr, including Level Flight for 4.1 hr at an altitude of 32-35 km. During the Level Flight, we successfully detected 420 downward gamma rays between 100 keV and 1 MeV at zenith angles below 60°. To obtain the flux of diffuse cosmic gamma rays, we first simulated their scattering in the atmosphere using Geant4, and for gamma rays detected at an atmospheric depth of 7.0 g cm–2 we found that 50% and 21% of the gamma rays at energies of 150 keV and 1 MeV, respectively, were scattered in the atmosphere prior to reaching the detector. Moreover, by using Geant4 simulations and the QinetiQ atmospheric radiation model, we estimated that the detected events consisted of diffuse cosmic and atmospheric gamma rays (79%), secondary photons produced in the instrument through the interaction between cosmic rays and materials surrounding the detector (19%), and other particles (2%). The obtained growth curve was comparable to Ling's model, and the fluxes of diffuse cosmic and atmospheric gamma rays were consistent with the results of previous experiments. The expected detection sensitivity of a future SMILE experiment measuring gamma rays between 150 keV and 20 MeV was estimated from our SMILE-I results and was found to be 10 times better than that of other experiments at around 1 MeV.
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observation of diffuse cosmic and atmospheric gamma rays at balloon altitudes with an electron tracking compton camera
arXiv: Instrumentation and Methods for Astrophysics, 2011Co-Authors: A. Takada, Hironobu Nishimura, Kazuki Ueno, Shigeto Kabuki, Kentaro Miuchi, K Hattori, Eiichi Mizuta, Shunsuke Kurosawa, H. Kubo, Tsutomu NagayoshiAbstract:We observed diffuse cosmic and atmospheric gamma rays at balloon altitudes with the Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I (SMILE-I) as the first step toward a future all-sky survey with a high sensitivity. SMILE-I employed an electron-tracking Compton camera comprised of a gaseous electron tracker as a Compton-scattering target and a scintillation camera as an absorber. The balloon carrying the SMILE-I detector was launched from the Sanriku Balloon Center of the Institute of Space and Astronomical Science/Japan Space Exploration Agency on September 1, 2006, and the Flight lasted for 6.8 hr, including Level Flight for 4.1 hr at an altitude of 32-35 km. During the Level Flight, we successfully detected 420 downward gamma rays between 100 keV and 1 MeV at zenith angles below 60 degrees. To obtain the flux of diffuse cosmic gamma rays, we first simulated their scattering in the atmosphere using Geant4, and for gamma rays detected at an atmospheric depth of 7.0 g cm-2, we found that 50% and 21% of the gamma rays at energies of 150 keV and 1 MeV, respectively, were scattered in the atmosphere prior to reaching the detector. Moreover, by using Geant4 simulations and the QinetiQ atmospheric radiation model, we estimated that the detected events consisted of diffuse cosmic and atmospheric gamma rays (79%), secondary photons produced in the instrument through the interaction between cosmic rays and materials surrounding the detector (19%), and other particles (2%). The obtained growth curve was comparable to Ling's model, and the fluxes of diffuse cosmic and atmospheric gamma rays were consistent with the results of previous experiments. The expected detection sensitivity of a future SMILE experiment measuring gamma rays between 150 keV and 20 MeV was estimated from our SMILE-I results and was found to be ten times better than that of other experiments at around 1 MeV.
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the observation of diffuse cosmic and atmospheric gamma rays with an electron tracking compton camera loaded on a balloon
Journal of the Physical Society of Japan, 2009Co-Authors: A. Takada, Hironobu Nishimura, Kazuki Ueno, Shigeto Kabuki, Kentaro Miuchi, K Hattori, H. Kubo, T Tanimori, K Tsuchiya, Shunsuke KurosawaAbstract:As next-generation MeV gamma-ray telescope, we have developed an electron-tracking Compton camera (ETCC) that consists of a gaseous tracker and an absorber. The ETCC obtains the energy and direction of both a scattered gamma ray and a recoil electron, and determines both the energy and direction of an incident gamma ray, photon by photon. Furthermore, this camera features powerful background rejection based on Compton-scattering kinematics. To prepare for future spacecraft loading, we planned the balloon experiment, “Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment” (SMILE). As the first step in SMILE, we demonstrated gamma-ray detection using our camera by observing diffuse cosmic gamma rays and secondary gamma rays generated by collisions between high-energy cosmic rays and nuclei in the air. On September 1, 2006, our detector was loaded on a balloon and launched from Sanriku Balloon Center, ISAS/JAXA. The balloon realized Level Flight at an altitude of about 35 km during a live time of 3.0 h. We ...
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observation of diffuse gamma ray with electron tracking compton imaging camera loaded on balloon
IEEE Nuclear Science Symposium, 2007Co-Authors: A. Takada, Hironobu Nishimura, Kazuki Ueno, Shigeto Kabuki, Kentaro Miuchi, K Hattori, H. Kubo, T Tanimori, K Tsuchiya, Shunsuke KurosawaAbstract:We have developed an electron tracking Compton camera (ETCC) as an MeV gamma-ray telescope in the next generation. Our detector consists of a gaseous time projection chamber and a position sensitive scintillation camera. In order to evaluate the performance of this detector, we constructed a Flight model detector as a balloon experiment for the observation of diffuse cosmic gamma rays and atmospheric gamma rays. The balloon launched on September 1 in 2006. The balloon reached to 35 km at altitude, and the Level Flight continued during 4.0 hours. We succeeded in the detection of about 200 downward gamma rays in the energy range of 100 keV-1 MeV during the 3.5 hours Level Flight (live time 3.0 hours). The detected photon number was consistent to the simulated one. Also, we measured the dependence of the gamma-ray flux on the zenith angle between 0deg and 90deg. Here we report on the detailed performance of the ETCC in this Flight.
Arya Soman - One of the best experts on this subject based on the ideXlab platform.
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regional patterns of pectoralis fascicle strain in the pigeon columba livia during Level Flight
The Journal of Experimental Biology, 2005Co-Authors: Arya Soman, Tyson L Hedrick, Andrew A BiewenerAbstract:SUMMARY Regional fascicle strains were recorded in vivo from the pectoralis of carneau pigeons using sonomicrometry during Level slow Flight, together with regional electromyography (EMG) and deltopectoral crest (DPC) strain measurements of whole muscle force. Fascicle strain measurements were obtained at four sites within the pectoralis: the anterior (Ant), middle (Mid) and posterior (Post) sternobrachium (SB), and the smaller thoracobrachium (TB). Strains were also recorded along the intramuscular aponeurosis of the pectoralis to assess its `in-series9 compliance with respect to strains of Post SB and TB fascicles. In-series segment strains were also obtained along Ant SB and Mid SB fascicles, which insert directly on the DPC without attaching to the intramuscular aponeurosis. In-series segment strains differed from 2% to 17.2%, averaging differences of 6.1% at the Ant SB site and 1.4% at the Mid SB site. Temporal patterns of in-series fascicle segment strain were similar at both sites. Regional fascicle strains also exhibited similar temporal patterns of lengthening and shortening and were most uniform in magnitude at the Ant SB, Mid SB and TB sites (total strain: 33.7%, 35.9% and 33.2% respectively), but were smaller at the Post SB site (24.4%). Strains measured along the aponeurosis tracked the patterns of contractile fascicle strain but were significantly lower in magnitude (19.1%). Fascicle lengthening strains (+25.4%) greatly exceeded net shortening strains (-6.5%) at all sites. Much of the variation in regional fascicle strain patterns resulted from variation of in vivo recording sites among individual animals, despite attempts to define consistent regions for obtaining in vivo recordings. No significant variation in EMG activation onset was found, but deactivation of the Ant SB occurred before the other muscle sites. Even so, the range of variation was small, with all muscle regions being activated midway through lengthening (upstroke) and turned off midway through shortening (downstroke). While subtle differences in the timing and rate of fascicle strain may relate to differing functional roles of the pectoralis, regional patterns of fascicle strain and activation suggest a generally uniform role for the muscle as a whole throughout the wingbeat cycle. Shorter fascicles located in more posterior regions of the muscle underwent generally similar strains as longer fascicles located in more anterior SB regions. The resulting differences in fiber length were accommodated by strain in the intramuscular aponeurosis and rotation of the pectoralis insertion with respect to the origin. As a result, longer Ant and Mid SB fascicles were estimated to contribute substantially more work per unit mass than shorter Post SB and TB fascicles. When the mass fractions of these regions are accounted for, our regional fascicle strain measurements show that the anterior regions of the pectoralis likely contribute 76%, and the posterior regions 24%, of the muscle9s total work output. When adjusted for mass fraction and regional fascicle strain, pectoralis work averaged 24.7±5.1 J kg -1 (206.6±43.5 W kg -1 ) during Level slow (∼4-5 m s -1 ) Flight.
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regional patterns of pectoralis fascicle strain in the pigeon columba livia during Level Flight
The Journal of Experimental Biology, 2005Co-Authors: Arya Soman, Tyson L Hedrick, Andrew A BiewenerAbstract:Regional fascicle strains were recorded in vivo from the pectoralis of carneau pigeons using sonomicrometry during Level slow Flight, together with regional electromyography (EMG) and deltopectoral crest (DPC) strain measurements of whole muscle force. Fascicle strain measurements were obtained at four sites within the pectoralis: the anterior (Ant), middle (Mid) and posterior (Post) sternobrachium (SB), and the smaller thoracobrachium (TB). Strains were also recorded along the intramuscular aponeurosis of the pectoralis to assess its 'in-series' compliance with respect to strains of Post SB and TB fascicles. In-series segment strains were also obtained along Ant SB and Mid SB fascicles, which insert directly on the DPC without attaching to the intramuscular aponeurosis. In-series segment strains differed from 2% to 17.2%, averaging differences of 6.1% at the Ant SB site and 1.4% at the Mid SB site. Temporal patterns of in-series fascicle segment strain were similar at both sites. Regional fascicle strains also exhibited similar temporal patterns of lengthening and shortening and were most uniform in magnitude at the Ant SB, Mid SB and TB sites (total strain: 33.7%, 35.9% and 33.2% respectively), but were smaller at the Post SB site (24.4%). Strains measured along the aponeurosis tracked the patterns of contractile fascicle strain but were significantly lower in magnitude (19.1%). Fascicle lengthening strains (+25.4%) greatly exceeded net shortening strains (-6.5%) at all sites. Much of the variation in regional fascicle strain patterns resulted from variation of in vivo recording sites among individual animals, despite attempts to define consistent regions for obtaining in vivo recordings. No significant variation in EMG activation onset was found, but deactivation of the Ant SB occurred before the other muscle sites. Even so, the range of variation was small, with all muscle regions being activated midway through lengthening (upstroke) and turned off midway through shortening (downstroke). While subtle differences in the timing and rate of fascicle strain may relate to differing functional roles of the pectoralis, regional patterns of fascicle strain and activation suggest a generally uniform role for the muscle as a whole throughout the wingbeat cycle. Shorter fascicles located in more posterior regions of the muscle underwent generally similar strains as longer fascicles located in more anterior SB regions. The resulting differences in fiber length were accommodated by strain in the intramuscular aponeurosis and rotation of the pectoralis insertion with respect to the origin. As a result, longer Ant and Mid SB fascicles were estimated to contribute substantially more work per unit mass than shorter Post SB and TB fascicles. When the mass fractions of these regions are accounted for, our regional fascicle strain measurements show that the anterior regions of the pectoralis likely contribute 76%, and the posterior regions 24%, of the muscle's total work output. When adjusted for mass fraction and regional fascicle strain, pectoralis work averaged 24.7+/-5.1 J kg(-1) (206.6+/-43.5 W kg(-1)) during Level slow (approximately 4-5 m s(-1)) Flight.