Takeoff

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Andrew A Biewener - One of the best experts on this subject based on the ideXlab platform.

  • aquatic and terrestrial Takeoffs require different hindlimb kinematics and muscle function in mallard ducks
    The Journal of Experimental Biology, 2020
    Co-Authors: Kari R Taylorburt, Andrew A Biewener
    Abstract:

    Mallard ducks are capable of performing a wide range of behaviors including nearly vertical Takeoffs from both terrestrial and aquatic habitats. The hindlimb plays a key role during Takeoffs from both media. However, because force generation differs in water versus on land, hindlimb kinematics and muscle function are likely modulated between these environments. Specifically, we hypothesize that hindlimb joint motion and muscle shortening are faster during aquatic Takeoffs, but greater hindlimb muscle forces are generated during terrestrial Takeoffs. In this study, we examined the hindlimb kinematics and in vivo contractile function of the lateral gastrocnemius (LG), a major ankle extensor and knee flexor, during Takeoffs from water versus land in mallard ducks. In contrast to our hypothesis, we observed no change in ankle angular velocity between media. However, the hip and metatarsophalangeal joints underwent large excursions during terrestrial Takeoffs but exhibited almost no motion during aquatic Takeoffs. The knee extended during terrestrial Takeoffs but flexed during aquatic Takeoffs. Correspondingly, LG fascicle shortening strain, shortening velocity, and pennation angle change were greater during aquatic Takeoffs than terrestrial Takeoffs due to the differences in knee motion. Nevertheless, we observed no significant differences in LG stress or work, but did see an increase in muscle power output during aquatic Takeoffs. Because differences in the physical properties of aquatic and terrestrial media require differing hindlimb kinematics and muscle function, animals such as mallards may be challenged to tune their muscle properties for movement across differing environments.

  • muscle function during Takeoff and landing flight in the pigeon columba livia
    The Journal of Experimental Biology, 2012
    Co-Authors: Angela Berg M Robertson, Andrew A Biewener
    Abstract:

    This study explored the muscle strain and activation patterns of several key flight muscles of the pigeon (Columba livia) during Takeoff and landing flight. Using electromyography (EMG) to measure muscle activation, and sonomicrometry to quantify muscle strain, we evaluated the muscle function patterns of the pectoralis, biceps, humerotriceps and scapulotriceps as pigeons flew between two perches. These recordings were analyzed in the context of three-dimensional wing kinematics. To understand the different requirements of Takeoff, midflight and landing, we compared the activity and strain of these muscles among the three flight modes. The pectoralis and biceps exhibited greater fascicle strain rates during Takeoff than during midflight or landing. However, the triceps muscles did not exhibit notable differences in strain among flight modes. All observed strain, activation and kinematics were consistent with hypothesized muscle functions. The biceps contracted to stabilize and flex the elbow during the downstroke. The humerotriceps contracted to extend the elbow at the upstroke-downstroke transition, followed by scapulotriceps contraction to maintain elbow extension during the downstroke. The scapulotriceps also appeared to contribute to humeral elevation. Greater muscle activation intensity was observed during Takeoff, compared with mid-flight and landing, in all muscles except the scapulotriceps. The timing patterns of muscle activation and length change differed among flight modes, yet demonstrated that pigeons do not change the basic mechanical actions of key flight muscles as they shift from flight activities that demand energy production, such as Takeoff and midflight, to maneuvers that require absorption of energy, such as landing. Similarly, joint kinematics were consistent among flight modes. The stereotypy of these neuromuscular and joint kinematic patterns is consistent with previously observed stereotypy of wing kinematics relative to the pigeon's body (in the local body frame) across these flight behaviors. Taken together, these observations suggest that the control of Takeoff and landing flight primarily involves modulation of overall body pitch to effect changes in stroke plane angle and resulting wing aerodynamics.

  • wing and body kinematics of Takeoff and landing flight in the pigeon columba livia
    The Journal of Experimental Biology, 2010
    Co-Authors: Angela M Berg, Andrew A Biewener
    Abstract:

    Takeoff and landing are critical phases in a flight. To better understand the functional importance of the kinematic adjustments birds use to execute these flight modes, we studied the wing and body movements of pigeons (Columba livia) during short-distance free-flights between two perches. The greatest accelerations were observed during the second wingbeat of Takeoff. The wings were responsible for the majority of acceleration during Takeoff and landing, with the legs contributing only one-quarter of the acceleration. Parameters relating to aerodynamic power output such as downstroke amplitude, wingbeat frequency and downstroke velocity were all greatest during Takeoff flight and decreased with each successive Takeoff wingbeat. This pattern indicates that downstroke velocity must be greater for accelerating flight to increase the amount of air accelerated by the wings. Pigeons used multiple mechanisms to adjust thrust and drag to accelerate during Takeoff and decelerate during landing. Body angle, tail angle and wing plane angles all shifted from more horizontal orientations during Takeoff to near-vertical orientations during landing, thereby reducing drag during Takeoff and increasing drag during landing. The stroke plane was tilted steeply downward throughout Takeoff (increasing from -60+/-5 deg. to -47+/-1 deg.), supporting our hypothesis that a downward-tilted stroke plane pushes more air rearward to accelerate the bird forward. Similarly, the stroke plane tilted upward during landing (increasing from -1+/-2 deg. to 17+/-7 deg.), implying that an upward-tilted stroke plane pushes more air forward to slow the bird down. Rotations of the stroke plane, wing planes and tail were all strongly correlated with rotation of the body angle, suggesting that pigeons are able to redirect aerodynamic force and shift between flight modes through modulation of body angle alone.

Massimo Medda - One of the best experts on this subject based on the ideXlab platform.

  • lTECHNICAL NOTE l Axillary Artery Access for Interventional Procedures
    2016
    Co-Authors: Luigi Inglese, Domenico Palmisano, Massimo Medda
    Abstract:

    l l Purpose: To evaluate axillary artery access for the interventional treatment of carotid or splanchnic arteries that have angulated Takeoff or complex anatomy when larger catheters (up to 9 F) are needed. Technique: The axillary artery approach was used to treat the left internal carotid artery (ICA) in 3 patients (2 angulated Takeoffs and 1 bovine arch) and a celiac axis aneurysm. An 8-F, 45-cm-long introducer sheath was inserted for the carotid procedures, whereas a 9-F, 90-cm sheath was chosen for the celiac aneurysm. Cerebral protection and stenting were successfully performed in all carotid patients; an 8340-mm stent-graft was implanted to exclude the celiac artery aneurysm. An 8-F vascular closure device was used in the axillary arteries; hemostasis was immediate, and no hematoma or other complications were recorded in follow-up. Conclusions: This preliminary experience revisits the axillary approach as an alternative access route for interventional procedures. In association with a vascular closure device, this approach should be considered as a useful and safe option for those interventional procedures in which larger sheaths or catheters are required to cope with difficult arterial anatomies. J Endovasc Ther 2004;11:414–418 Key words: internal carotid artery, bovine arch, celiac axis aneurysm, stent-graft, axillary artery, vascular closure device l l Address for correspondence and reprints: Luigi Inglese, MD, Department of Cardiovascular Radiology

  • Axillary artery access for interventional procedures.
    Journal of Endovascular Therapy, 2004
    Co-Authors: Luigi Inglese, Tommaso Lupattelli, Giannignazio Luigi Carbone, Domenico Palmisano, Carmine Musto, Nadia Mollichelli, Massimo Medda
    Abstract:

    PURPOSE: To evaluate axillary artery access for the interventional treatment of carotid or splanchnic arteries that have angulated Takeoff or complex anatomy when larger catheters (up to 9 F) are needed. TECHNIQUE: The axillary artery approach was used to treat the left internal carotid artery (ICA) in 3 patients (2 angulated Takeoffs and 1 bovine arch) and a celiac axis aneurysm. An 8-F, 45-cm-long introducer sheath was inserted for the carotid procedures, whereas a 9-F, 90-cm sheath was chosen for the celiac aneurysm. Cerebral protection and stenting were successfully performed in all carotid patients; an 8x40-mm stent-graft was implanted to exclude the celiac artery aneurysm. An 8-F vascular closure device was used in the axillary arteries; hemostasis was immediate, and no hematoma or other complications were recorded in follow-up. CONCLUSIONS: This preliminary experience revisits the axillary approach as an alternative access route for interventional procedures. In association with a vascular closure device, this approach should be considered as a useful and safe option for those interventional procedures in which larger sheaths or catheters are required to cope with difficult arterial anatomies.

Gerard J Tellis - One of the best experts on this subject based on the ideXlab platform.

  • global Takeoff of new products culture wealth or vanishing differences
    Marketing Science, 2008
    Co-Authors: Deepa Chandrasekaran, Gerard J Tellis
    Abstract:

    The authors study the Takeoff of 16 new products across 31 countries 430 categories to analyze how and why Takeoff varies across products and countries. They test the effect of 12 hypothesized drivers of Takeoff using a parametric hazard model. The authors find that the average time to Takeoff varies substantially between developed and developing countries, between work and fun products, across cultural clusters, and over calendar time. Products take off fastest in Japan and Norway, followed by other Nordic countries, the United States, and some countries of Midwestern Europe. Takeoff is driven by culture and wealth plus product class, product vintage, and prior Takeoff. Most importantly, time to Takeoff is shortening over time and Takeoff is converging across countries. The authors discuss the implications of these findings.

  • global Takeoff of new products culture wealth or vanishing differences
    Social Science Research Network, 2007
    Co-Authors: Deepa Chandrasekaran, Gerard J Tellis
    Abstract:

    The authors study the Takeoff of 16 new products across 31 countries (430 categories) to analyze how and why time-to-Takeoff varies across products and countries. They test the effect of 12 hypothesized drivers of time-to-Takeoff using a parametric hazard model. The authors find that the average time-to-Takeoff varies substantially between developed and developing countries, between work and fun products, across cultural clusters, and over calendar time. Products take off fastest in Japan and Norway, followed by other Nordic countries, the US, and some countries of Mid-western Europe. Time-to-Takeoff is driven by culture and wealth plus product class, product vintage and prior Takeoff. Most importantly, time-to-Takeoff is shortening over time and Takeoff is converging across countries. The authors discuss the implications of these findings.

  • the international Takeoff of new products the role of economics culture and country innovativeness
    Marketing Science, 2003
    Co-Authors: Gerard J Tellis, Stefan Stremersch, Eden Yin
    Abstract:

    Sales Takeoff is vitally important for the management of new products. Limited prior research on this phenomenon covers only the United States. This study addresses the following questions about Takeoff in Europe: 1 Does Takeoff occur as distinctly in other countries, as it does in the United States? 2 Do different categories and countries have consistently different times-to-Takeoff? 3 What economic and cultural factors explain the intercountry differences? 4 Should managers use a sprinkler or waterfall strategy for the introduction of new products across countries? We gathered data on 137 new products across 10 categories and 16 European countries. We adapted the threshold rule for identifying Takeoff Golder and Tellis 1997 to this multinational context. We specify a parametric hazard model to answer the questions above. The major results are as follows: 1 Sales of most new products display a distinct Takeoff in various European countries, at an average of six years after introduction. 2 The time-to-Takeoff varies substantially across countries and categories. It is four times shorter for entertainment products than for kitchen and laundry appliances. It is almost half as long in Scandinavian countries as in Mediterranean countries. 3 While culture partially explains intercountry differences in time-to-Takeoff, economic factors are neither strong nor robust explanatory factors. 4 These results suggest distinct advantages to a waterfall strategy for introducing products in international markets.

Angela Berg M Robertson - One of the best experts on this subject based on the ideXlab platform.

  • muscle function during Takeoff and landing flight in the pigeon columba livia
    The Journal of Experimental Biology, 2012
    Co-Authors: Angela Berg M Robertson, Andrew A Biewener
    Abstract:

    This study explored the muscle strain and activation patterns of several key flight muscles of the pigeon (Columba livia) during Takeoff and landing flight. Using electromyography (EMG) to measure muscle activation, and sonomicrometry to quantify muscle strain, we evaluated the muscle function patterns of the pectoralis, biceps, humerotriceps and scapulotriceps as pigeons flew between two perches. These recordings were analyzed in the context of three-dimensional wing kinematics. To understand the different requirements of Takeoff, midflight and landing, we compared the activity and strain of these muscles among the three flight modes. The pectoralis and biceps exhibited greater fascicle strain rates during Takeoff than during midflight or landing. However, the triceps muscles did not exhibit notable differences in strain among flight modes. All observed strain, activation and kinematics were consistent with hypothesized muscle functions. The biceps contracted to stabilize and flex the elbow during the downstroke. The humerotriceps contracted to extend the elbow at the upstroke-downstroke transition, followed by scapulotriceps contraction to maintain elbow extension during the downstroke. The scapulotriceps also appeared to contribute to humeral elevation. Greater muscle activation intensity was observed during Takeoff, compared with mid-flight and landing, in all muscles except the scapulotriceps. The timing patterns of muscle activation and length change differed among flight modes, yet demonstrated that pigeons do not change the basic mechanical actions of key flight muscles as they shift from flight activities that demand energy production, such as Takeoff and midflight, to maneuvers that require absorption of energy, such as landing. Similarly, joint kinematics were consistent among flight modes. The stereotypy of these neuromuscular and joint kinematic patterns is consistent with previously observed stereotypy of wing kinematics relative to the pigeon's body (in the local body frame) across these flight behaviors. Taken together, these observations suggest that the control of Takeoff and landing flight primarily involves modulation of overall body pitch to effect changes in stroke plane angle and resulting wing aerodynamics.

Luigi Inglese - One of the best experts on this subject based on the ideXlab platform.

  • lTECHNICAL NOTE l Axillary Artery Access for Interventional Procedures
    2016
    Co-Authors: Luigi Inglese, Domenico Palmisano, Massimo Medda
    Abstract:

    l l Purpose: To evaluate axillary artery access for the interventional treatment of carotid or splanchnic arteries that have angulated Takeoff or complex anatomy when larger catheters (up to 9 F) are needed. Technique: The axillary artery approach was used to treat the left internal carotid artery (ICA) in 3 patients (2 angulated Takeoffs and 1 bovine arch) and a celiac axis aneurysm. An 8-F, 45-cm-long introducer sheath was inserted for the carotid procedures, whereas a 9-F, 90-cm sheath was chosen for the celiac aneurysm. Cerebral protection and stenting were successfully performed in all carotid patients; an 8340-mm stent-graft was implanted to exclude the celiac artery aneurysm. An 8-F vascular closure device was used in the axillary arteries; hemostasis was immediate, and no hematoma or other complications were recorded in follow-up. Conclusions: This preliminary experience revisits the axillary approach as an alternative access route for interventional procedures. In association with a vascular closure device, this approach should be considered as a useful and safe option for those interventional procedures in which larger sheaths or catheters are required to cope with difficult arterial anatomies. J Endovasc Ther 2004;11:414–418 Key words: internal carotid artery, bovine arch, celiac axis aneurysm, stent-graft, axillary artery, vascular closure device l l Address for correspondence and reprints: Luigi Inglese, MD, Department of Cardiovascular Radiology

  • Axillary artery access for interventional procedures.
    Journal of Endovascular Therapy, 2004
    Co-Authors: Luigi Inglese, Tommaso Lupattelli, Giannignazio Luigi Carbone, Domenico Palmisano, Carmine Musto, Nadia Mollichelli, Massimo Medda
    Abstract:

    PURPOSE: To evaluate axillary artery access for the interventional treatment of carotid or splanchnic arteries that have angulated Takeoff or complex anatomy when larger catheters (up to 9 F) are needed. TECHNIQUE: The axillary artery approach was used to treat the left internal carotid artery (ICA) in 3 patients (2 angulated Takeoffs and 1 bovine arch) and a celiac axis aneurysm. An 8-F, 45-cm-long introducer sheath was inserted for the carotid procedures, whereas a 9-F, 90-cm sheath was chosen for the celiac aneurysm. Cerebral protection and stenting were successfully performed in all carotid patients; an 8x40-mm stent-graft was implanted to exclude the celiac artery aneurysm. An 8-F vascular closure device was used in the axillary arteries; hemostasis was immediate, and no hematoma or other complications were recorded in follow-up. CONCLUSIONS: This preliminary experience revisits the axillary approach as an alternative access route for interventional procedures. In association with a vascular closure device, this approach should be considered as a useful and safe option for those interventional procedures in which larger sheaths or catheters are required to cope with difficult arterial anatomies.