496 research outputs found

    An effective approach to diagnosis and surgical repair of refractory medial epicondylitis

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    BACKGROUND: Medial epicondylitis of the elbow, an overuse injury characterized by angiofibroblastic tendinosis of the common flexor-pronator origin, generally responds to nonoperative treatment. Refractory cases may require surgical debridement and repair. This study discusses physical examination and imaging findings and an updated surgical technique used in patients with recalcitrant medial epicondylitis. METHODS: The surgical records of 60 patients with refractory medial epicondylitis were reviewed. All received a course of nonoperative care. After 3 to 6 months of failed therapy, imaging was obtained, and surgical intervention was offered when indicated. This open procedure consisted of thorough debridement with repair and restoration of the flexor-pronator origin, using a suture anchor. Accelerated rehabilitation, emphasizing early motion, was used. One-year follow-ups were obtained. The Mayo Elbow Performance Score was calculated preoperatively and postoperatively. RESULTS: Pronation weakness at 90 degrees was a critical physical examination finding. Preoperative magnetic resonance images demonstrated pathologic partial tearing at the flexor-pronator origin. Ulnar neuritis was addressed in 20%. Postoperatively, the Mayo Elbow Performance Score significantly increased (preoperatively, 58 +/- 7.7; postoperatively, 88 +/- 7.8; P = 5.6E-34), and pain significantly decreased (preoperatively, 2.2 +/- 0.3; postoperatively, 0.6 +/- 0.5; P = 3.8E-33). There was one retear in a patient noncompliant with the postoperative protocol. He responded positively to reoperation. CONCLUSION: Identification of weakness on pronation is a reliable physical examination finding for determining clinically significant pathologic changes in patients with medial epicondylitis. Debridement with restoration of the flexor-pronator origin is an efficacious procedure. In this large series of patients, surgical repair with aggressive rehabilitation was shown to be reliable and safe in restoring function and relieving pain in recalcitrant cases of medial epicondylitis

    Thermal Compensation of Photogrammetric Dimensional Measurements in Non-standard Anisothermal Environments

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    Manufacturers are currently facing large volume metrology challenges driven by thermal effects such as variation in refractive index and thermal expansion. Thermal expansion is one of the largest contributors to measurement uncertainty and it can often be difficult to realise the standard 20° C temperature required. The current process for dimensional measurement requires that the temperature is measured at the instrument, and the entire measurement volume is scaled linearly by the same factor. Unfortunately, this assumes that temperatures are uniform all over the measurand, which is seldom the case particularly at large volume scales.Useful for deformation measurement, photogrammetry is increasingly employed in industry, which in some cases can exhibit uncertainties comparable with the industry standard laser tracker. By measuring temperature more broadly and combining this data with finite element analysis, it is possible to compensate each of these points in 3D space along the X, Y and Z axes. Actively creating challenging metrology conditions with highly localized temperature gradients, and maximum temperatures in excess of 45° C has allowed this approach to be tested. Results show that in many cases it is possible to make localized predictions of displacement within the range of photogrammetric measurement uncertainty

    Range-wide patterns of geographic variation in songs of Golden-crowned Sparrows (Zonotrichia atricapilla)

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    Discrete geographic variation, or dialects, in songs of songbirds arise as a consequence of complex interactions between ecology and song learning. Four of the five species of Zonotrichia sparrows, including the model species White-crowned Sparrow (Z. leucophrys), have been studied with respect to the causes and consequences of geographic variation in song. Within White-crowned Sparrows, subspecies that migrate farther have larger range size of dialects. Here, we assessed geographic patterns of song variation in the fifth species of this genus, the Golden-crowned Sparrow (Z. atricapilla). We analyzed field-recorded songs from 2 sampling periods (1996–1998 and 2006–2013) covering most of its breeding range in western North America. All songs began with a descending whistle and most songs consisted of 3–4 phrases that contained combinations of whistles, buzzes, and trills. We identified 13 discrete song types based on unique sequences of phrase types and frequency changes between phrases. Over 90% of individuals sang 1 of 5 song types, and we found clear dialect structure composed of these 5 common song types. The geographic range of dialects spanned large distances (500 to 1,700 km), resembling the geographic structure of dialects in the long-distance migrant Gambel’s White-crowned Sparrow (Z. l. gambelli), though locations of dialect boundaries differ between species. Because both Golden-crowned Sparrows and Gambel’s White-crowned Sparrows migrate similarly long distances, our study provides support to the hypothesis that dialect range size correlates with migration distance. We found little evidence of change in dialect composition in 4 populations that were sampled 15 years apart, which suggests that the dialect structure is stable across multiple generations. Our study opens the door for further comparisons to investigate links between ecology and the emergence of song dialects in this well-studied genus

    bony as Grotesque: The Dilemma of National Identity in Arthur Upfield's Bony Series, 1930-1950

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    A reading of Upfield's detective series in terms of James Donald's idea of the 'grotesque', shifting between idealised national type and their 'degenerate low Others'

    Range-wide patterns of geographic variation in songs of Golden-crowned Sparrows (\u3ci\u3eZonotrichia atricapilla\u3c/i\u3e)

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    Discrete geographic variation, or dialects, in songs of songbirds arise as a consequence of complex interactions between ecology and song learning. Four of the five species of Zonotrichia sparrows, including the model species White-crowned Sparrow (Z. leucophrys), have been studied with respect to the causes and consequences of geographic variation in song. Within White-crowned Sparrows, subspecies that migrate farther have larger range size of dialects. Here, we assessedgeographic patterns of song variation in the fifth species of this genus, the Golden-crowned Sparrow (Z. atricapilla). We analyzed field-recorded songs from 2 sampling periods (1996–1998 and 2006–2013) covering most of its breeding range in western North America. All songs began with a descending whistle and most songs consisted of 3–4 phrases that contained combinations of whistles, buzzes, and trills. We identified 13 discrete song types based on unique sequences of phrase types and frequency changes between phrases. Over 90% of individuals sang 1 of 5 song types, and we found clear dialect structure composed of these 5 common song types. The geographic range of dialects spanned large distances (500 to 1,700 km), resembling the geographic structure of dialects in the long-distance migrant Gambel’s White-crowned Sparrow (Z. l. gambelli), though locations of dialect boundaries differ between species. Because both Golden-crowned Sparrows and Gambel’s White-crowned Sparrows migrate similarly long distances, our study provides support to the hypothesis that dialect range size correlates with migration distance. We found little evidence of change in dialect composition in 4 populations that were sampled 15 years apart, which suggests that the dialect structure is stable across multiple generations. Our study opens the door for further comparisons to investigate links between ecology and the emergence of song dialects in this well-studied genus. La variación geográfica discreta, o los dialectos, en los cantos de las aves canoras se originan como consecuencia de interacciones complejas entre la ecología y el aprendizaje de los cantos. Cuatro de las 5 especies de Zonotrichia, incluyendo la especie modelo Z. leucophrys, han sido estudiadas con respecto a las causas y consecuencias de la variación geográfica en el canto. Al interior de la especie Z. leucophrys, las subespecies que migran más lejos tienen dialectos con rangos más amplios. En este trabajo evaluamos los patrones de variación del canto en la quinta especie de este género, Z. atricapilla. Analizamos cantos grabados en el campo de dos períodos de muestreo (1996–1998 y 2006–2013), cubriendo la mayor parte de su rango reproductivo en el oeste de América del Norte. Todos los cantos comienzan con un silbido descendente y la mayoría de los cantos consistieron en 3–4 frases con combinaciones de silbidos, zumbidos y trinos. Identificamos 13 tipos discretos de cantos basados en secuencias únicas de tipos de frases y en cambios de frecuencia entre frases. Más del 90% de los individuos cantaron uno de los 5 tipos de cantos, y encontramos una clara estructura del dialecto compuesta por estos 5 tipos de cantos comunes. El rango geogra´fico de los dialectos abarcó grandes distancias (500 a 1,700 km), asemeja´ndose a la estructura geográfica de los dialectos de la especie migratoria de larga distancia Z. l. gambelli, aunque las localidades de frontera de los dialectos difirieron entre especies. Debido a que Z. atricapilla y Z. l. gambelli migran ambas largas distancias, nuestro estudio apoya la hipótesis de que el tamaño del rango del dialecto se correlaciona con la distancia de migración. Encontramos poca evidencia de cambios en la composición del dialecto en cuatro poblaciones que fueron muestreadas con una diferencia de 15 años, lo que sugiere que la estructura del dialecto es estable a través de varias generaciones. Nuestro estudio abre la puerta a comparaciones adicionales para investigar los vínculos entre la ecología y la emergencia de dialectos del canto en este género bien estudiado

    Range-wide patterns of geographic variation in songs of Golden-crowned Sparrows (\u3ci\u3eZonotrichia atricapilla\u3c/i\u3e)

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    Discrete geographic variation, or dialects, in songs of songbirds arise as a consequence of complex interactions between ecology and song learning. Four of the five species of Zonotrichia sparrows, including the model species White-crowned Sparrow (Z. leucophrys), have been studied with respect to the causes and consequences of geographic variation in song. Within White-crowned Sparrows, subspecies that migrate farther have larger range size of dialects. Here, we assessed geographic patterns of song variation in the fifth species of this genus, the Golden-crowned Sparrow (Z. atricapilla). We analyzed field-recorded songs from 2 sampling periods (1996–1998 and 2006–2013) covering most of its breeding range in western North America. All songs began with a descending whistle and most songs consisted of 3–4 phrases that contained combinations of whistles, buzzes, and trills. We identified 13 discrete song types based on unique sequences of phrase types and frequency changes between phrases. Over 90% of individuals sang 1 of 5 song types, and we found clear dialect structure composed of these 5 common song types. The geographic range of dialects spanned large distances (500 to 1,700 km), resembling the geographic structure of dialects in the long-distance migrant Gambel’s White-crowned Sparrow (Z. l. gambelli), though locations of dialect boundaries differ between species. Because both Golden-crowned Sparrows and Gambel’s White-crowned Sparrows migrate similarly long distances, our study provides support to the hypothesis that dialect range size correlates with migration distance. We found little evidence of change in dialect composition in 4 populations that were sampled 15 years apart, which suggests that the dialect structure is stable across multiple generations. Our study opens the door for further comparisons to investigate links between ecology and the emergence of song dialects in this well-studied genus

    The modern use of the extended humeral head (cuff tear arthropathy) hemiarthroplasty.

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    Today, the treatment of osteoarthritis in the rotator cuff-deficient population is largely dominated by reverse shoulder arthroplasty (RSA). Despite the popularity of and increased familiarity with this procedure, the complication rate of RSA remains significant. An extended humeral head hemiarthroplasty may provide a less invasive alternative for select patients with cuff tear arthropathy (CTA) and preserved glenohumeral active elevation. With the indications for reverse arthroplasty expanding to younger patients, there are concerns about the longevity of this implant, as well as the associated revision burden. In the setting of failed RSA, the bone stock available for glenosphere baseplate fixation can be inadequate for reimplantation. The treatment strategies for complex shoulder deformities and failed RSA are limited by patient-specific issues, such as anatomy and risk factors. In this review, we discuss the potential role of extended humeral head hemiarthroplasty (CTA hemiarthroplasty) as a primary surgical option in select patients (1) who have preserved elevation \u3e 90°, (2) who have maintained stability (intact coracoacromial ligament), and (3) who desire to circumvent the complications associated with RSA. Furthermore, CTA hemiarthroplasty may be used for severe glenoid erosion, for a fragmented acromion, and in the revision setting for failed RSA aimed at a reliable salvage procedure

    Thermal Compensation of Photogrammetric Dimensional Measurements in Non-standard Anisothermal Environments

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    AbstractManufacturers are currently facing large volume metrology challenges driven by thermal effects such as variation in refractive index and thermal expansion. Thermal expansion is one of the largest contributors to measurement uncertainty and it can often be difficult to realise the standard 20° C temperature required. The current process for dimensional measurement requires that the temperature is measured at the instrument, and the entire measurement volume is scaled linearly by the same factor. Unfortunately, this assumes that temperatures are uniform all over the measurand, which is seldom the case particularly at large volume scales.Useful for deformation measurement, photogrammetry is increasingly employed in industry, which in some cases can exhibit uncertainties comparable with the industry standard laser tracker. By measuring temperature more broadly and combining this data with finite element analysis, it is possible to compensate each of these points in 3D space along the X, Y and Z axes. Actively creating challenging metrology conditions with highly localized temperature gradients, and maximum temperatures in excess of 45° C has allowed this approach to be tested. Results show that in many cases it is possible to make localized predictions of displacement within the range of photogrammetric measurement uncertainty

    Thermal compensation using the hybrid metrology approach compared to traditional scaling:DET 2016 Special Edition

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    Control of temperature in large-scale manufacturing environments is not always practical or economical, introducing thermal effects including variation in ambient refractive index and thermal expansion. Thermal expansion is one of the largest contributors to measurement uncertainty; however, temperature distributions are not widely measured. Uncertainties can also be introduced in scaling to standard temperature. For more complex temperature distributions with non-linear temperature gradients, uniform scaling is unrealistic. Deformations have been measured photogrammetrically in two thermally challenging scenarios with localised heating. Extended temperature measurement has been tested with finite element analysis to assess a compensation methodology for coordinate measurement. This has been compared to commonly used uniform scaling and has outperformed this with a highly simplified finite element analysis simulation in scaling a number of coordinates at once. This work highlighted the need for focus on reproducible temperature measurement for dimensional measurement in non-standard environments. </jats:p

    Charger 1: A New Facility for Z-Pinch Research

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    Charger 1 is a multipurpose pulsed power laboratory located on Redstone Arsenal, with a focus on fusion propulsion relevant experiments involving testing z-pinch diodes, pulsed magnetic nozzle and other related physics experiments. UAH and its team of pulsed power researchers are investigating ways to increase and optimize fusion production from Charger 1. Currently the team has reached high-power testing. Due to the unique safety issues related to high power operations the UAH/MSFC team has slowed repair efforts to develop safety and operations protocols. The facility is expected to be operational by the time DZP 2017 convenes. Charger 1 began life as the Decade Module 2, an experimental prototype built to prove the Decade Quad pinch configuration. The system was donated to UAH by the Defense Threat Reduction Agency (DRTA) in 2012. For the past 5 years a UAH/MSFC/Boeing team has worked to refurbish, assemble and test the system. With completion of high power testing in summer 2017 Charger 1 will become operational for experimentation. Charger 1 utilizes a Marx Bank of 72 100-kV capacitors that are charged in parallel and discharged in series. The Marx output is compressed to a pulse width of approximately 200 ns via a pulse forming network of 32 coaxial stainless steel tubes using water as a dielectric. After pulse compression a set of SF6 switches are triggered, allowing the wave front to propagate through the output line to the load. Charger 1 is capable of storing 572-kJ of energy and time compressing discharge to less than 250 ns discharge time producing a discharge of about 1 TW of discharge with 1 MV and 1 MA peak voltage and current, respectively. This capability will be used to study energy yield scaling and physics from solid density target as applied to advanced propulsion research
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