Toppling statues and making space: prospects for anti-racist cultural activism

Statues have long been recognized as impositions of a particular past that legitimize a power-laden present. Consequently, toppling statues, and engaging with the space they once occupied, opens up the possibility of new and multiple narratives. This article takes this moment of possibility as its starting point. Drawing from nine case studies in five countries, and from thirty-one interviews with cultural activists and other stakeholders, we identify three patterns that emerge in the aftermath of removing statues. First, removing a statue changes the hegemonic narrative of the space it once occupied. Second, stakeholders resist the imposition of a singular new narrative on that space. Third, policymakers and institutions attempt to regulate the space and the narratives it carries. We argue, further, that whilst attempts to impose a new, single narrative on the same site are widely met with obstacles, empty plinths become multivocal sites of memory in their own right

Prosthetic overhang is the most effective way to prevent scapular conflict in a reverse total shoulder prosthesis

Methods An average and a "worst case scenario" shape in A-P view in a 2-D computer model of a scapula was created, using data from 200 "normal" scapulae, so that the position of the glenoid and humeral component could be changed as well as design features such as depth of the polyethylene insert, the size of glenosphere, the position of the center of rotation, and downward glenoid inclination. The model calculated the maximum adduction (notch angle) in the scapular plane when the cup of the humeral component was in conflict with the scapula. Results A change in humeral neck shaft inclination from 155 degrees to 145 degrees gave a 10 degrees gain in notch angle. A change in cup depth from 8 mm to 5 mm gave a gain of 12 degrees. With no inferior prosthetic overhang, a lateralization of the center of rotation from 0 mm to 5 mm gained 16 degrees. With an inferior overhang of only 1 mm, no effect of lateralizing the center of rotation was noted. Downward glenoid inclination of 0 boolean OR to 10 boolean OR gained 10 degrees. A change in glenosphere radius from 18 mm to 21 mm gained 31 degrees due to the inferior overhang created by the increase in glenosphere. A prosthetic overhang to the bone from 0 mm to 5 mm gained 39 degrees. Interpretation Of all 6 solutions tested, the prosthetic overhang created the biggest gain in notch angle and this should be considered when designing the reverse arthroplasty and defining optimal surgical technique

Measurements of the current density profile with tangential Thomson scattering in RTP

The electron drift velocity (v(d,e)) profile is measured with tangential Thomson scattering (TTS). From this, the current density (j) profile is determined, extending over 60% of the plasma diameter (2a) with a spatial resolution of 12% of a. The statistical error of similar to 10% is in agreement with the expected accuracy based on simulation studies. Two analysis methods are compared and found to agree. Results of TTS in electron cyclotron heated discharges with peaked and hollow j profiles are in good agreement with neo-classical resistivity

Omarthrose ecentrée : symposium

Cuff tear arthropathy is defined as the combination of a gleno-humeral arthritis and a massive rotators cuff tear. It is generally admitted that the cuff tear, or its deficiency jeopardises the results of anatomic prosthesis. Grammont imagined and grew the concept of the reverse prosthesis whose aim was to remedy the insufficiency of the rotator cuff and whose use has dramatically modified the therapeutic approach in these complicated situations. The aim of this symposium is to analyse the results of shoulder arthroplasty (anatomic prosthesis, bipolar or reverse) in cuff tear arthropathy, in massive and isolated cuff tears which justify the use of prosthetic surgery, and in centered osteoarthritis with deficient cuff also justifying this use. Massive cuff tears and cuff tear arthropathy have been considered as the stages of a same pathology by Hamada whose classification has been used for the purposes of this study. Out of the 738 initial prosthesis, 111 have been eliminated because of death, incomplete files or lost of sight, without any known complication. Out of the remaining 627 who were used as a basis for this symposium (representing 85% of initial cases), 570 who still had their prosthesis were reviewed and their functional results analysed after 2 years or more. The population was mainly female (72%) who were injured on the dominant side (75%) with a mean age of 72 years. The preoperative Constant score was in average 24 and 24% of the patients had already been operated on their shoulder. For those who had an acetabulization of the acromion, the strength in external rotation was significantly less satisfying and the lesion of the infraspinatus and the teres minor were more frequent. 48 hemiarthroplasties, 52 bipolar and 527 reverse prosthesis were studied. At revision, with an average follow up of 52 months, the revision rate was 23% for hemiarthroplasties, 14% for reversed prosthesis and only 8% for bipolar prosthesis. The prosthesis was removed in 21% of hemiarthroplasties, 5% of reverse and 2% of bipolar. No infection to report in the hemi group or the bipolar group, whereas there was an infection rate of 5% in the reverse group. Nevertheless, the Constant score was significantly better with reverse (62) than with bipolar (45) or hemi (44). The active elevation was also better with the reverse whereas the external rotation was not as good as with anatomic prosthesis. The analytic study of the results of the reverse prosthesis shows a negative influence of the lesion of the sub-scapularis and the teres minor. The results are disappointing with young patients and those who had surgical precedents. On X-ray, we can notice 0.5% of humeral loosening withouth any correlation to the fact that the implant is cemented or not, 3.6% of glenoid loosening and 68% of scapular notches without any significant change on the Constant score. Their occurrence is correlated to a preoperative rising of the humeral head and a superior glenoid lesion. It is observed more frequently with the supero-lateral approach compared to the delto-pectoral one. The frequency of these notches grows with the follow up and their occurrence is often associated to humeral radiolucent lines. On the long term, the survival rate of these prosthesis is 89% at 10 years. The Constant score deteriorates gradually after 7 years; this seems to be linked to the occurrence of x-ray modifications in the years that followed. The main complications observed with reverse prosthesis were the infections (5.1%), the glenoid problems (5.1%), the instabilities (3.6%), the acromion fractures (3.0%). Infections can be treated by a wash out and antibiotics in the first 3 months, then the removal of the prosthesis becomes necessary. The instabilities occur more often for males, with delto-pectoral approach and with 36mm diameter glenoids. The glenoid problems are frequent in the first years and often due to technical errors or material defects (unscrewing of the glenosphere). Acromion fractures have an important clinical impact when they concern the spine and there healing is difficult to obtain, whichever method is used. In conclusion, the use of a prosthesis for cuff tear arthropathies must be thought about, especially in massive cuff tear without osteoarthritis, in patients with previous surgery, and in patients younger than 70. If the active elevation is conserved and the patient is young, the use of an hemi or a bipolar prosthesis can be debated. In other cases, the indication of a reverse prosthesis is preferable given that the clinical results are better. In these cases, the surgical technique must be accurate, bearing in mind the advantages and disadvantages of the two possible approaches, the type of implant (36 vs 42), the position and orientation of the glenoid baseplate according to the pre-operative bone wear, the orientation of the humeral implant, the need for reinsertion of the subscapularis and, maybe, the possibility of an associated transfer of the latissimus dorsi

Omarthrose ecentrée : symposium

Cuff tear arthropathy is defined as the combination of a gleno-humeral arthritis and a massive rotators cuff tear. It is generally admitted that the cuff tear, or its deficiency jeopardises the results of anatomic prosthesis. Grammont imagined and grew the concept of the reverse prosthesis whose aim was to remedy the insufficiency of the rotator cuff and whose use has dramatically modified the therapeutic approach in these complicated situations. The aim of this symposium is to analyse the results of shoulder arthroplasty (anatomic prosthesis, bipolar or reverse) in cuff tear arthropathy, in massive and isolated cuff tears which justify the use of prosthetic surgery, and in centered osteoarthritis with deficient cuff also justifying this use. Massive cuff tears and cuff tear arthropathy have been considered as the stages of a same pathology by Hamada whose classification has been used for the purposes of this study. Out of the 738 initial prosthesis, 111 have been eliminated because of death, incomplete files or lost of sight, without any known complication. Out of the remaining 627 who were used as a basis for this symposium (representing 85% of initial cases), 570 who still had their prosthesis were reviewed and their functional results analysed after 2 years or more. The population was mainly female (72%) who were injured on the dominant side (75%) with a mean age of 72 years. The preoperative Constant score was in average 24 and 24% of the patients had already been operated on their shoulder. For those who had an acetabulization of the acromion, the strength in external rotation was significantly less satisfying and the lesion of the infraspinatus and the teres minor were more frequent. 48 hemiarthroplasties, 52 bipolar and 527 reverse prosthesis were studied. At revision, with an average follow up of 52 months, the revision rate was 23% for hemiarthroplasties, 14% for reversed prosthesis and only 8% for bipolar prosthesis. The prosthesis was removed in 21% of hemiarthroplasties, 5% of reverse and 2% of bipolar. No infection to report in the hemi group or the bipolar group, whereas there was an infection rate of 5% in the reverse group. Nevertheless, the Constant score was significantly better with reverse (62) than with bipolar (45) or hemi (44). The active elevation was also better with the reverse whereas the external rotation was not as good as with anatomic prosthesis. The analytic study of the results of the reverse prosthesis shows a negative influence of the lesion of the sub-scapularis and the teres minor. The results are disappointing with young patients and those who had surgical precedents. On X-ray, we can notice 0.5% of humeral loosening withouth any correlation to the fact that the implant is cemented or not, 3.6% of glenoid loosening and 68% of scapular notches without any significant change on the Constant score. Their occurrence is correlated to a preoperative rising of the humeral head and a superior glenoid lesion. It is observed more frequently with the supero-lateral approach compared to the delto-pectoral one. The frequency of these notches grows with the follow up and their occurrence is often associated to humeral radiolucent lines. On the long term, the survival rate of these prosthesis is 89% at 10 years. The Constant score deteriorates gradually after 7 years; this seems to be linked to the occurrence of x-ray modifications in the years that followed. The main complications observed with reverse prosthesis were the infections (5.1%), the glenoid problems (5.1%), the instabilities (3.6%), the acromion fractures (3.0%). Infections can be treated by a wash out and antibiotics in the first 3 months, then the removal of the prosthesis becomes necessary. The instabilities occur more often for males, with delto-pectoral approach and with 36mm diameter glenoids. The glenoid problems are frequent in the first years and often due to technical errors or material defects (unscrewing of the glenosphere). Acromion fractures have an important clinical impact when they concern the spine and there healing is difficult to obtain, whichever method is used. In conclusion, the use of a prosthesis for cuff tear arthropathies must be thought about, especially in massive cuff tear without osteoarthritis, in patients with previous surgery, and in patients younger than 70. If the active elevation is conserved and the patient is young, the use of an hemi or a bipolar prosthesis can be debated. In other cases, the indication of a reverse prosthesis is preferable given that the clinical results are better. In these cases, the surgical technique must be accurate, bearing in mind the advantages and disadvantages of the two possible approaches, the type of implant (36 vs 42), the position and orientation of the glenoid baseplate according to the pre-operative bone wear, the orientation of the humeral implant, the need for reinsertion of the subscapularis and, maybe, the possibility of an associated transfer of the latissimus dorsi

Electron thermal transport in RTP: filaments, barriers and bifurcations

Experiments with strong localized electron cyclotron heating (ECH) in the RTP tokamak show that electron heat transport is governed by alternating layers of good and bad thermal conduction. For central deposition hot T-e filaments are observed inside the q = 1 radius. Moving the ECH resonance from the centre to the edge of the plasma results in discrete steps of the central electron temperature. The transitions occur when the minimum q value crosses q = 1, 2, 5/2 or 3, and correspond to the loss of a transport barrier situated close to the rational q value. Close to the transitions a new type of sawtooth activity is observed, characterized by the formation of sharp off-axis maxima on the T, profile, which collapse abruptly. The formation of the off-axis maxima is attributed to heat deposition precisely \u27on top of\u27 a transport barrier