206,407 research outputs found

    Revision of reversed shoulder arthroplasty : is a reoperation possible?

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    Introduction. As the number of reversed shoulder arthroplasty (RSA) procedures increases, the revision rate will also increase. In case of severe bone insufficiency, instability or infection of the primary RSA, revision to another RSA is preferable but not always possible. Hemiarthroplasty (HA), spacers and resection arthroplasty (RA) have been described in this indication. Materials and methods. Between 2004 and 2016, 20 shoulders in 19 patientswere treated at Ghent University Hospital for failed revision of RSA. Nine received a megahead prosthesis, a spacerwas implanted in 6, and 5 underwent RA. Results. Indications for implantation of a megahead prosthesis were loosening RSA (n = 5), infection (n = 4), dislocation (n = 1) and nerve irritation (n = 1). Improvement of range ofmotionwas observed. Anterosuperior migration of the prosthesis was noted in 2 patients. Another 2 patients were ultimately revised to RSA. Seven permanent spacerswere implanted for infection, of which 2 remain in place till today. The other 5 were revised to RSA. Of the 5 patients treated with RA, 3 were revised further on to RSA, resulting in pain relief and regain of function. Discussion. Our study shows that amegahead prosthesis has better functional results than RA, but is inferior to RSA. Due to increasing surgical experience and improving technique, 9 patients could ultimately be reconverted to another RSA. A review of current literature is presented. In HA and RA, the functional results are poor, and pain relief is uncertain. Results of spacers are variable and can be satisfactory. Arthrodesis is a last resort. Conclusion. In our case series study, a hemiarthroplasty can be performed in case of failure of RSA. However, the results are inferior to another RSA

    Food for thought: how nutrients regulate root system architecture

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    The spatial arrangement of the plant root system (root system architecture, RSA) is very sensitive to edaphic and endogenous signals that report on the nutrient status of soil and plant. Signalling pathways underpinning RSA responses to individual nutrients, particularly nitrate and phosphate, have been unravelled. Researchers have now started to investigate interactive effects between two or more nutrients on RSA. Several proteins enabling crosstalk between signalling pathways have recently been identified. RSA is potentially an important trait for sustainable and/or marginal agriculture. It is generally assumed that RSA responses are adaptive and optimise nutrient uptake in a given environment, but hard evidence for this paradigm is still sparse. Here we summarize recent advances made in these areas of research

    An efficient and secure RSA--like cryptosystem exploiting R\'edei rational functions over conics

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    We define an isomorphism between the group of points of a conic and the set of integers modulo a prime equipped with a non-standard product. This product can be efficiently evaluated through the use of R\'edei rational functions. We then exploit the isomorphism to construct a novel RSA-like scheme. We compare our scheme with classic RSA and with RSA-like schemes based on the cubic or conic equation. The decryption operation of the proposed scheme turns to be two times faster than RSA, and involves the lowest number of modular inversions with respect to other RSA-like schemes based on curves. Our solution offers the same security as RSA in a one-to-one communication and more security in broadcast applications.Comment: 18 pages, 1 figur

    Products of two proportional primes

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    In RSA cryptography numbers of the form [Formula: see text], with [Formula: see text] and [Formula: see text] two distinct proportional primes play an important role. For a fixed real number [Formula: see text] we formalize this by saying that an integer [Formula: see text] is an RSA-integer if [Formula: see text] and [Formula: see text] are primes satisfying [Formula: see text]. Recently Dummit, Granville and Kisilevsky showed that substantially more than a quarter of the odd integers of the form [Formula: see text] up to [Formula: see text], with [Formula: see text] both prime, satisfy [Formula: see text]. In this paper, we investigate this phenomenon for RSA-integers. We establish an analogue of a strong form of the prime number theorem with the logarithmic integral replaced by a variant. From this we derive an asymptotic formula for the number of RSA-integers [Formula: see text] which is much more precise than an earlier one derived by Decker and Moree in 2008. </jats:p

    Road Safety Audit for the Intersection of US 59 and IA 9 in Osceola County, Iowa Final Report, March 2012

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    The Iowa Department of Transportation (DOT) requested a road safety audit (RSA) of the US 59/IA 9 intersection in northwestern Iowa, just south of the Minnesota border, to assess intersection environmental issues and crash history and recommend appropriate mitigation to address the identified safety issues at the intersection. Although the number of crashes at the location has not been significantly higher than the statewide average for similar intersections, the severity of these crashes has been of concern. This RSA was unique in that it included intersection video observation and recorded traffic conflict data analysis, along with the daylight and nighttime field reviews. This report outlines the findings and recommendations of the RSA team for addressing the safety concerns at this intersection

    RSA Study of Dimers

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    The first theoretical study of a dimer's adsorption process at homogenous surface is presented. By using the RSA algorithm, we show example monolayers, discuss estimations of random jamming coverage and measure the surface blocking function, which could be used for calculating real systems kinetics. We also found the correlation function for generated coverages and analyzed orientational ordering inside the adsorbed monolayer. Results were compared with theoretical and experimental data. Keywords: adsorption, RSA, monolayer, colloid particlesComment: 13 pages, 13 figure
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