A Favard type theorem for orthogonal polynomials on the unit circle from a three term recurrence formula

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Invasive head and neck cutaneous squamous cell carcinoma: clinical and histopathological characteristics, frequency of local recurrence and metastasis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Digit systems over commutative rings

Let epsilon be a commutative ring with identity and P is an element of epsilon[x] be a polynomial. In the present paper we consider digit representations in the residue class ring epsilon[x]/(P). In particular, we are interested in the question whether each A is an element of epsilon[x]/(P) can be represented modulo P in the form e(0)+ e(1)x + ... + e(h)x(h), where the e(i) is an element of epsilon[x]/(P) are taken from a fixed finite set of digits. This general concept generalizes both canonical number systems and digit systems over finite fields. Due to the fact that we do not assume that 0 is an element of the digit set and that P need not be monic, several new phenomena occur in this context.

O gênero acadêmico: resumos nas áreas de Antropologia, Linguística e Ciência Política

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vector Mode Analysis of Ring-Core Fibers: Design Tools for Spatial Division Multiplexing

Design tools have existed for decades for standard step-index fibers, with analytical expressions for cutoff conditions as a function of core size, refractive indexes, and wavelength. We present analytical expressions for cutoff conditions for fibers with a ring-shaped propagation region. We validate our analytical expressions against numerical solutions, as well as via asymptotic analysis yielding the existing solutions for standard step-index fiber. We demonstrate the utility of our solutions for optimizing fibers supporting specific eigenmode behaviors of interest for spatial division multiplexing. In particular, we address large mode separation for orbital angular momentum modes and fibers supporting only modes with a single intensity ring.

Critérios de Divisibilidade e Aplicação em Sala de Aula

Pós-graduação em Matemática - IBILCE

Direct retrospective comparison of adalimumab and infliximab in preventing early postoperative endoscopic recurrence after ileocaecal resection for crohn's disease: results from the MULTIPER database

Both adalimumab [ADA] and infliximab [IFX] seem to be effective in the prevention of early postoperative endoscopic recurrence [EPER] after ileocaecal resection in Crohn's disease [CD] patients. There is lack of data with direct comparison between the two agents in the postoperative scenario. The aim of this study was to compare the rates of EPER in patients treated with ADA and IFX after ileocaecal resection for CD. This was a multicentre retrospective analysis of EPER rates in CD patients after ileocaecal resections, from seven referral centres in three countries. Endoscopic recurrence was defined as Rutgeerts' score ≥ i2. The patients were allocated according to treatment to two groups: ADA or IFX. The EPER rates were compared between the two treatment groups. Among the 168 patients included in the database, 96 received anti-tumour necrosis factor [TNF] agents after resection [37 in the ADA and 59 in the IFX groups] and were included in this comparative study. The groups were comparable in all baseline characteristics, mainly age, gender, previous resections, perianal CD, and mono or combination therapy. EPER was identified in 9/37 [24.32%] in the ADA group vs 16/59 [27.12%] in the IFX group [p = 0.815]. In this retrospective direct comparison between ADA and IFX therapy after ileocaecal resection, there was no significant difference between the two anti-TNF agents in terms of EPER rates. However, prospective randomised studies are needed to confirm these data and better define the role of each agent in the prevention of EPER.

Conventional versus biological therapy for prevention of postoperative endoscopic recurrence in patients with Crohn's disease: an international, multicenter, and observational study

Postoperative endoscopic recurrence (PER) occurs in nearly 80% of patients 1 year after ileocecal resection in patients with Crohn's disease (CD). Biological agents were more effective in reducing the rates of PER in comparison with conventional therapy, in prospective trials. The aim of this study was to compare the PER rates of biological versus conventional therapy after ileocecal resections in patients with CD in real-world practice. The MULTIPER (Multicenter International Postoperative Endoscopic Recurrence) database is a retrospective analysis of PER rates in CD patients after ileocecal resection, from 7 referral centers in 3 different countries. All consecutive patients who underwent ileocecal resections between 2008 and 2012 and in whom colonoscopies had been performed up to 12 months after surgery, were included. Recurrence was defined as Rutgeerts' score ≥i2. The patients were allocated to either biological or conventional therapy after surgery, and PER rates were compared between the groups. Initially, 231 patients were evaluated, and 63 were excluded. Of the 168 patients in the database, 96 received anti-tumor necrosis factor agents and 72 were treated with conventional therapy after resection. The groups were comparable regarding age, gender, and perianal disease. There was longer disease duration, more previous resections, and more open surgical procedures in patients on biologicals postoperatively. PER was identified in 25/96 (26%) patients on biological therapy and in 24/72 (33.3%) patients on conventional therapy (P=0.310). In this retrospective observational analysis from an international database, no difference was observed between biological and conventional therapy in preventing PER after ileocecal resections in CD patients.

Biological therapy for the prevention and treatment of postoperative endoscopic recurrence in Crohn's disease: time for acceptance?

In most patients, postoperative endoscopic recurrence (PER) occurs 1 year after abdominal resection for Crohn’s disease (CD). Preventing PER is essential for disease control, as most patients develop further clinical and surgical recurrences. Conventional therapy with nitroimidazoles, aminosalicylates, and immunomodulators have limited efficacy for preventing PER. Initial trials with biological therapy (infliximab and adalimumab) showed promising results in preventing PER, and the efficacy of these drugs seems higher than that with conventional therapy. The aim of this review is to outline the results of studies that used infliximab or adalimumab for preventing and treating PER in CD patients. Data with both agents are available, and a few, small prospective trials have shown the efficacy of these drugs in patients with a high risk for recurrence. We believe that, in 2013, biological agents will be better accepted for the prevention PER in CD patients, in addition to the already existing data. Larger trials are still underway, and their results will certainly determine the role of these agents in PER, which develops after bowel resection for CD.

Risk factors for postoperative endoscopic recurrence in Crohn's disease: a Brazilian observational study

Introduction: Postoperative endoscopic recurrence (PER) is the initial event after intestinal resection in Crohn’s disease (CD), and after a few years most patients present with progressive symptoms and complications related to the disease. The identification of risk factors for PER can help in the optimization of postoperative therapy and contribute to its prevention. Methods: Retrospective, longitudinal, multicenter, observational study involving patients with CD who underwent ileocolic resections. The patients were allocated into two groups according to the presence of PER and the variables of interest were analyzed to identify the associated factors for recurrence. Results: Eighty-five patients were included in the study. The mean period of the first postoperative colonoscopy was 12.8 (3–120) months and PER was observed in 28 patients (32.9%). There was no statistical difference in relation to gender, mean age, duration of CD, family history, previous intestinal resections, smoking, Montreal classification, blood transfusion, residual CD, surgical technique, postoperative complications, presence of granulomas at histology, specimen extension and use of postoperative biological therapy. The preoperative use of corticosteroids was the only variable that showed a significant difference between the groups in univariate analysis, being more common in patients with PER (42.8% vs. 21%; p = 0.044). Conclusions: PER was observed in 32.9% of the patients. The preoperative use of corticosteroids was the only risk factor associated with PER in this observational analysis.