Counting polygon dissections in the projective plane

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The generic Hanna Neumann conjecture and post correspondence problem

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Comparison of two osteoporotic fracture management pathways: experience at 1 year

Introduction: Osteoporosis presenting as low-impact fractures to traumatology units is often undiagnosed and under-treated. Results from the Osteocare study in Lausanne (a nurse based intervention, passive pathway) showed that only 19% of patients received management for osteoporosis, and in the literature [1], the rate is between 10-25%. We have evaluated a different management concept, based on the systematic assessment of patients with osteoporotic fractures during and after hospitalization (active pathway). Methods: Inpatients admitted to the Department of Musculoskeletal Medicine for a fragility fracture were identified by a nurse according to a predefined questionnaire and were then clinically evaluated by a doctor. Based on the results, a management plan was proposed to the patients. Patients could choose between follow up either by their GP or by the Centre of Bone Disease of the CHUV. For patients who chose follow-up in our Centre, we assessed their adherence to medical follow-up 1 year inclusion. The results of patients who had been evaluated in our cohort between the 1 November 2008 and the 1 December 2009 were analysed. Results: 573 inpatients received specific management of their osteoporotic fracture over 18 months. The mean age was 77 y (31-99), 81% were women (203 hip fractures, 40 pelvis fractures, 101 arm fractures, 57 vertebral fractures, 63 ankle fractures, and 25 others sites). During the study period, 303 patients received a proposition of a specific treatment. 39 (13%) chose a follow up with the GP, 19 (6%) dead and 245 (81%) preferred a follow up in our Centre. After 1 year, 166 (67%) patients are under follow up in our outpatient clinic. Conclusion: With an active clinical pathway that starts during the hospitalization, consisting on a nursing evaluation followed by a medical consultation by an expert in osteoporosis, the adherence increased from 19% to 67% in terms of follow up. These results lead us to propose a consultation with a doctor experienced in osteoporosis after all osteoporotic fractures.

Prise en charge des troubles oculomoteurs après effraction iatrogène de l'orbite au cours d'interventions sinusiennes endoscopiques [Management of motility disorders secondary to iatrogenic orbital fracture during endoscopic sinus surgery.]

PURPOSE: Orbital wall fracture may occur during endoscopic sinus surgery, resulting in oculomotor disorders. We report the management of four cases presenting with this surgical complication. METHODS: A non-comparative observational retrospective study was carried out on four patients presenting with diplopia after endoscopic ethmoidal sinus surgery. All patients underwent full ophthalmologic and orthoptic examination as well as orbital imaging. RESULTS: All four patients presented with diplopia secondary to a medial rectus lesion confirmed by orbital imaging. A large horizontal deviation as well as limitation of adduction was present in all cases. Surgical management consisted of conventional recession-resection procedures in three cases and muscle transposition in one patient. A useful field of binocular single vision was restored in two of the four patients. CONCLUSION: Orbital injury may occur during endoscopic sinus surgery and cause diplopia, usually secondary to medial rectus involvement due to the proximity of this muscle to the lamina papyracea of the ethmoid bone. Surgical management is based on orbital imaging, duration of the lesion, evaluation of anterior segment vasculature, results of forced duction testing and intraoperative findings. In most cases, treatment is aimed at the symptoms rather than the cause, and the functional prognosis remains guarded.

The simultaneous conjugacy problem in groups of piecewise linear functions

Guba and Sapir asked, in their joint paper [8], if the simultaneous conjugacy problem was solvable in Diagram Groups or, at least, for Thompson's group F. We give an elementary proof for the solution of the latter question. This relies purely on the description of F as the group of piecewise linear orientation-preserving homeomorphisms of the unit. The techniques we develop allow us also to solve the ordinary conjugacy problem as well, and we can compute roots and centralizers. Moreover, these techniques can be generalized to solve the same questions in larger groups of piecewise-linear homeomorphisms.

Freeze-fracture study of Trichomonas vaginalis

The freeze-fracture technique was used to analyse the organization of the plasma membrane, as well as membranes of cytoplasmic organelles, of the pathogenic protozoan Trichomonas vaginalis. Rosettes formed by 4 to 14 intramembranous particles were seen on the fracture faces of the membrane lining the anterior flagella as well as in fracture faces of the plasma membrane enclosing the anterior region of the protozoan and in cytoplasmic organelles. Special organization of the membrane particles were also seen in the region of association of the recurrent flagellum to the cell body.

An Empirical Examination of the R&D Boundaries of the Firm - A Problem-Solving Perspective

We consider, both theoretically and empirically, how different organization modes are aligned to govern the efficient solving of technological problems. The data set is a sample from the Chinese consumer electronics industry. Following mainly the problem solving perspective (PSP) within the knowledge based view (KBV), we develop and test several PSP and KBV hypotheses, in conjunction with competing transaction cost economics (TCE) alternatives, in an examination of the determinants of the R&D organization mode. The results show that a firm’s existing knowledge base is the single most important explanatory variable. Problem complexity and decomposability are also found to be important, consistent with the theoretical predictions of the PSP, but it is suggested that these two dimensions need to be treated as separate variables. TCE hypotheses also receive some support, but the estimation results seem more supportive of the PSP and the KBV than the TCE.

Geometria integral i convexitat en espais de curvatura holomorfa constant

En aquest treball es tracten qüestions de la geometria integral clàssica a l'espai hiperbòlic i projectiu complex i a l'espai hermític estàndard, els anomenats espais de curvatura holomorfa constant. La geometria integral clàssica estudia, entre d'altres, l'expressió en termes geomètrics de la mesura de plans que tallen un domini convex fixat de l'espai euclidià. Aquesta expressió es dóna en termes de les integrals de curvatura mitja. Un dels resultats principals d'aquest treball expressa la mesura de plans complexos que tallen un domini fixat a l'espai hiperbòlic complex, en termes del que definim com volums intrínsecs hermítics, que generalitzen les integrals de curvatura mitja. Una altra de les preguntes que tracta la geometria integral clàssica és: donat un domini convex i l'espai de plans, com s'expressa la integral de la s-èssima integral de curvatura mitja del convex intersecció entre un pla i el convex fixat? A l'espai euclidià, a l'espai projectiu i hiperbòlic reals, aquesta integral correspon amb la s-èssima integral de curvatura mitja del convex inicial: se satisfà una propietat de reproductibitat, que no es té en els espais de curvatura holomorfa constant. En el treball donem l'expressió explícita de la integral de la curvatura mitja quan integrem sobre l'espai de plans complexos. L'expressem en termes de la integral de curvatura mitja del domini inicial i de la integral de la curvatura normal en una direcció especial: l'obtinguda en aplicar l'estructura complexa al vector normal. La motivació per estudiar els espais de curvatura holomorfa constant i, en particular, l'espai hiperbòlic complex, es troba en l'estudi del següent problema clàssic en geometria. Quin valor pren el quocient entre l'àrea i el perímetre per a successions de figures convexes del pla que creixen tendint a omplir-lo? Fins ara es coneixia el comportament d'aquest quocient en els espais de curvatura seccional negativa i que a l'espai hiperbòlic real les fites obtingudes són òptimes. Aquí provem que a l'espai hiperbòlic complex, les cotes generals no són òptimes i optimitzem la superior.

Symmetry for a Dirichlet-Neumann problem arising in water waves

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The non-linear Dirichlet problem in Hadamard manifolds

We prove existence theorems for the Dirichlet problem for hypersurfaces of constant special Lagrangian curvature in Hadamard manifolds. The first results are obtained using the continuity method and approximation and then refined using two iterations of the Perron method. The a-priori estimates used in the continuity method are valid in any ambient manifold.