Breakdown of smoothness for the Muskat problem

In this paper we show that there exist analytic initial data in the stable regime for the Muskat problem such that the solution turns to the unstable regime and later breaks down i.e. no longer belongs to $C^4$.Comment: 93 pages, 10 figures (6 added

No entropy enigmas for N=4 dyons

We explain why multi-centered black hole configurations where at least one of the centers is a large black hole do not contribute to the indexed degeneracies in theories with N=4 supersymmetry. This is a consequence of the fact that such configurations, although supersymmetric, belong to long supermultiplets. As a result, there is no entropy enigma in N=4 theories, unlike in N=2 theories.Comment: 14 page

Guillain-barré Syndrome In The Elderly: Clinical, Electrophysiological, Therapeutic And Outcome Features

There are few papers devoted to geriatric Guillain-Barré (GBS) and many related issues remain unanswered. Objective: To describe clinical, electrophysiological and therapeutic features in this age. Method: Clinico-epidemiological data and therapy of GBS patients older than 60 years were reviewed. Hughes scores were used to quantify neurological deficit and define outcome. Results: Among 18 patients (mean age 64.8 years), 9 had evident prodrome and 80% noticed initially sensory-motor deficit. Demyelinating GBS was found in 8 and axonal in 6 subjects. There was one Miller-Fisher and 3 unclassified cases. Plasmapheresis (PFX) was single therapy in 12 patients and intravenous immunoglobulin (IVIg) in 2. Disability scores just before therapy were similar in both groups, so as short and long term outcome. Conclusion: Axonal GBS seems to be more frequent in the elderly and this may have prognostic implications. PFX and IVIg were suitable options, but complications were noticed with PFX. Prospective studies are needed to better understand and manage GBS in the elderly.633 B772775Kuwabara, S., Guillain-Barré syndrome: Epidemiology, pathophysiology and management (2004) Drugs, 64, pp. 597-610Hughes, R.A.C., Rees, J.H., Clinical and epidemiological features of Guillain-Barré syndrome (1997) J Infect Dis, 176 (SUPPL. 2), pp. S92-S98Hartung, H.P., Willison, H.J., Kieseier, B.C., Acute immunoinflammatory neuropathy: Update on Guillain-Barré syndrome (2002) Curr Opin Neurol, 15, pp. 571-577Efficiency of plasma exchange in Guillain-Barré syndrome: Role of replacement fluids (1987) Ann Neurol, 22, pp. 753-761Greenwood, R.J., Newsom Davis, J.M., Hughes, R.A.C., Controlled trial of plasma exchange in acute inflammatory polyradiculoneuropathy (1984) Lancet, 1, pp. 877-879Osterman, P.O., Lundemo, G., Pirskanen, R., Beneficial effects of plasma exchange in acute inflammatory polyradiculoneuropathy (1984) Lancet, 2, pp. 1296-1299Plasmapheresis and acute Guillain-Barré syndrome (1985) Neurology, 35, pp. 1096-1104Plasma exchange in Guillain-Barré syndrome: One-year follow-up (1992) Ann Neurol, 32, pp. 94-97Van Der Meché, F.G.A., Schmitz, P.I.M., A randomized trial comparing intravenous immune globulin and plasma exchange in Guillain-Barré syndrome (1992) N Engl J Med, 326, pp. 1123-1129Randomised trial of plasma exchange, intravenous immunoglobulin, and combined treatments in Guillain-Barré syndrome (1997) Lancet, 349, pp. 225-230Sridharan, G.V., Tallis, R.C., Gautam, P.C., Guillain-Barré syndrome in the elderly: A retrospective comparative study (1993) Gerontology, 39, pp. 170-175Winner, S.J., Evans, J.G., Guillain-Barré syndrome in Oxfordshire: Clinical features in relation to age (1993) Age Ageing, 22, pp. 164-170Yamashita, S., Morinaga, T., Matsumoto, K., Sakamoto, T., Kaku, N., Matsukura, S., Severe Guillain-Barré syndrome in aged patients: The effect of plasmapheresis (1992) Intern Med, 31, pp. 1313-1316Rana, S.S., Rana, S., Intravenous immunoglobulins versus plasmapheresis in older patients with Guillain-Barré syndrome (1999) J Am Geriatr Soc, 47, pp. 1387-1388Asbury, A.K., Cornblath, D.R., Assessment of current diagnostic criteria for Guillain-Barré syndrome (1990) Ann Neurol, 27 (SUPPL.), pp. S21-S24Seneviratne, U., Guillain-Barré syndrome (2000) Postgrad Med J, 76, pp. 774-782Hughes, R.A.C., Newsom-Davis, J.M., Perkin, G.D., Pierce, J.M., Controlled trial of prednisolone in acute polyneuropathy (1978) Lancet, 2, pp. 750-753Rocha, M.S.G., Brucki, S.M.D., Carvalho, A.A.S., Lima, U.W.P., Epidemiologic features of Guillain-Barre syndrome in São Paulo, Brazil (2004) Arq Neuropsiquiatr, 62, pp. 33-37Van Der Meche, F.G., Visser, L.H., Jacobs, B.C., Endtz, H.P., Meulstee, J., Van Doom, P.A., Guillain-Barré syndrome: Multifactorial mechanisms versus defined subgroups (1997) J Infect Dis, 176 (SUPPL. 2), pp. S99-S102Sheth, R.D., Riggs, J.E., Hobbs, G.R., Gutmann, L., Age and Guillain-Barré syndrome severity (1996) Muscle Nerve, 19, pp. 375-377Dias-Tosta, E., Kuckelhaus, C.S., Guillain-Barre syndrome in a population less than 15 years old in Brazil (2002) Arq Neuropsiquiatr, 60, pp. 367-37

Thermodynamics of Higher Spin Black Holes in AdS3_3

We discuss the thermodynamics of recently constructed three-dimensional higher spin black holes in SL(N,R)\times SL(N,R) Chern-Simons theory with generalized asymptotically-anti-de Sitter boundary conditions. From a holographic perspective, these bulk theories are dual to two-dimensional CFTs with W_N symmetry algebras, and the black hole solutions are dual to thermal states with higher spin chemical potentials and charges turned on. Because the notion of horizon area is not gauge-invariant in the higher spin theory, the traditional approaches to the computation of black hole entropy must be reconsidered. One possibility, explored in the recent literature, involves demanding the existence of a partition function in the CFT, and consistency with the first law of thermodynamics. This approach is not free from ambiguities, however, and in particular different definitions of energy result in different expressions for the entropy. In the present work we show that there are natural definitions of the thermodynamically conjugate variables that follow from careful examination of the variational principle, and moreover agree with those obtained via canonical methods. Building on this intuition, we derive general expressions for the higher spin black hole entropy and free energy which are written entirely in terms of the Chern-Simons connections, and are valid for both static and rotating solutions. We compare our results to other proposals in the literature, and provide a new and efficient way to determine the generalization of the Cardy formula to a situation with higher spin charges.Comment: 30 pages, PDFLaTeX; v2: typos corrected, explicit expressions for the free energy adde

Drug Hypersensitivity Quality of Life Questionnaire: validation procedures and first results of the Portuguese version

Background: Hypersensitivity reactions to drugs are unpredictable and can be very complex and severe, even life threatening. Assess its impact on patient’s health related quality of life (HRQoL) is crucial. The Drug Hypersensitivity Quality of Life Questionnaire (DrHy-Q) is the only validated disease-specific HRQoL questionnaire. We aimed to translate and cross-cultural validate the DrHy-Q to the Portuguese population. It was also our purpose to determine the impact of drug hypersensitivity on patients’ HRQoL. Methods: The translation and cross-cultural adaptation of the DrHy-Q to Portuguese was performed according to standards. Reliability of the DrHy-Q Portuguese version was assessed in terms of internal consistency and test–retest reliability. Structural validity, divergent validity (with a generic health related QoLQ-PGWBI) and discriminant validity were also evaluated. Forty patients accepted to participate in the validation phase. The Portuguese version of the DrHy-Q was applied to 260 consecutively adult patients, studied in our Department for suspected drug hypersensitivity. Results: The Portuguese DrHy-Q showed adequate internal consistency (Cronbach’s ¿ = 0.938), good test–retest reliability [ICC = 0.713 (95% CI 0.488–0.850] and one-dimensional structure. No significant correlation was found between the DrHy-Q and the PGWBI total scores (r = - 0.010, p = 0.957). Two hundred of patients completed the study: 78.5% female; mean age = 44 ± 15 years. Mean DrHy-Q score was 36.8 ± 12.6. Two clinical factors significantly predict DrHy-Q total score: clinical manifestations and number of suspected drugs. Patients with anaphylaxis (ß = 11.005; 95% CI 5.523; 16.487), urticaria/angioedema (ß = 7.770; 95% CI 2.600; 12.940) and other manifestations (ß = 7.948; 95% CI 1.933; 13.962) are more likely to have higher DrHy-Q total score than patients with maculopapular exanthema. Patients with = 2 suspected drugs are also more likely to have worse QoL (ß = 7.927; 95% CI 3.687; 12.166). Conclusion: The Portuguese version of DrHy-Q revealed adequate validity and reliability, indicating that it is appropriate to assess the impact of drug hypersensitivity on patients’ HRQoL, providing data for a better comprehension and management of our patients. Moreover, our results highlight that the severity of the drug hypersensitivity reaction and the number of suspected drugs have impact on patient’s DrHy-QoL

Surface dissipation in nanoelectromechanical systems: Unified description with the standard tunneling model and effects of metallic electrodes

By modifying and extending recent ideas [C. Seoanez et al., Europhys. Lett. 78, 60002 (2007)], a theoretical framework to describe dissipation processes in the surfaces of vibrating micro- and nanoelectromechanical devices, thought to be the main source of friction at low temperatures, is presented. Quality factors as well as frequency shifts of flexural and torsional modes in doubly clamped beams and cantilevers are given, showing the scaling with dimensions, temperature, and other relevant parameters of these systems. Full agreement with experimental observations is not obtained, leading to a discussion of limitations and possible modifications of the scheme to reach a quantitative fitting to experiments. For nanoelectromechanical systems covered with metallic electrodes, the friction due to electrostatic interaction between the flowing electrons and static charges in the device and substrate is also studied.Comment: 17 pages, 7 figure