Publications by authors named "Christopher Jarrett"

Meeting international commitments to protect 17% of terrestrial ecosystems worldwide will require >3 million square kilometers of new protected areas and strategies to create those areas in a way that respects local communities and land use. In 2000-2016, biological and social scientists worked to increase the protected proportion of Peru's largest department via 14 interdisciplinary inventories covering >9 million hectares of this megadiverse corner of the Amazon basin. In each landscape, the strategy was the same: convene diverse partners, identify biological and sociocultural assets, document residents' use of natural resources, and tailor the findings to the needs of decision-makers.

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Clinical assessment of abnormal neuromechanics is typically performed by manipulation of the affected limbs; a process with low inter- and intra-rater reliability. This paper aims at formalizing a framework that closes the loop between a clinician's expertise and computational algorithms, to enhance the clinician's diagnostic capabilities during physical manipulation. The framework's premise is that the dynamics that can be measured by manipulation of a limb are distinct between movement disorders.

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This paper presents a model inversion procedure for a viscoelastic compliant element contained within a rotary series elastic actuator (SEA). Model inversion plays an important role in enabling accurate model-based control of physical human-robot interaction (HRI) with SEAs. If the compliant element of the SEA is elastomeric, analytically inverting its model is non-trivial due to the presence of complex non-linear terms.

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Physical human-robot interaction (pHRI) is an important consideration in the design of rehabilitation exoskeletons. Series Elastic Actuators (SEAs) are seen as a promising method of introducing compliance and comfort to robotic exoskeletons. Recently, authors have proposed the use of elastomers in SEAs, rather than springs, but there is a dearth of literature comparing how the two compliant elements are perceived by humans.

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Motor learning is a critical component of the rehabilitation process; however, it can be difficult to separate the fundamental causes of a learning deficit when physical impairment is a confounding factor. In this paper, a new technique is proposed to augment the residual ability of physically impaired patients with a robotic rehabilitation exoskeleton, such that motor learning can be studied independently of physical impairment. The proposed technique augments the velocity of an on-screen cursor relative to the restricted physical motion.

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A novel form of acoustic modulation of light from an incoherent source has been detected in water as well as in turbid media. We demonstrate that patterns of modulated light intensity appear to propagate as the optical shadow of the density variations caused by ultrasound within an illuminated ultrasonic focal zone. This pattern differs from previous reports of acousto-optical interactions that produce diffraction effects that rely on phase shifts and changes in light directions caused by the acoustic modulation.

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Background: Early reports on modern ceramic-on-ceramic total hip replacements have demonstrated excellent clinical and radiographic results with few cases of catastrophic failure, which, in the case of earlier designs, often had been caused by implant fracture. Several reports, however, have noted the presence of audible squeaking. The purpose of the present study was to determine the incidence of squeaking in association with the use of this bearing couple.

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Minifragment implants provide several advantages for the stabilization of distal humerus fractures. Compared with small fragment implants, minifragment implants may provide enhanced fracture fixation because a greater number of screws can be placed into the distal fragments. In addition, minifragment plates are easier to contour and less prominent.

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We present the case of a patient with symptomatic refractory multidirectional shoulder instability who was treated with staged bilateral anterior and posterior glenoid bone augmentation after previous failed arthroscopic and open procedures. The patient was pain free postoperatively and has not had symptoms of instability in either shoulder. At her most recent followup, 24 months after surgery, she had nearly full symmetric shoulder range of motion without anterior or posterior apprehension signs.

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Specialty gloves and buddy taping of adjacent fingers may cushion impact and dissipate twisting forces so that hands, thumbs, and fingers are protected during play. When fractures occur, athletes must be protected from contact until healing has progressed to a point where reinjury or complications are unlikely and performance standards and expectations can be met. This article outlines a program of fracture management principles and progressive graduated rehabilitation that phase the hand-injured athlete first into general conditioning and non-ball-handling drills, then into return to hand impact activities, body contact, ball handling, and catching with the use of protective hand gear.

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The treatment of femoral shaft fractures has become safe and reproducible since the advent of popularization of intramedullary nailing, however, many femoral shaft fractures are complicated by associated fractures, extensive comminution, extensive contamination, and arterial injury compartmental syndrome. Other conditions associated with the use of femoral nailing include femora nonunions, broken hardware, acute fractures with prior implants, and infections. The management of these complex femoral shaft fractures demands special techniques for successful outcome.

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