TD 2648 - Empréstimos com Amortizações Condicionadas à Renda: cenários de financiamento de estudantes de ensino superior no Brasil

Empréstimos com amortizações condicionadas à renda (ECRs) são um financiamento que otimiza as eficiências transacionais envolvidas no monopólio governamental de tributação da renda pessoal. Protege o devedor contra períodos de baixa renda, pois as amortizações variam de acordo com as flutuações no seu rendimento ao longo da vida. Há décadas conjugam proteção social com sustentabilidade fiscal no financiamento de estudantes de ensino superior em número crescente de países. Este trabalho simula desenhos alternativos de ECR para financiamento estudantil no Brasil. Funções de cópula são aplicadas para captar padrões de mobilidade na distribuição de rendimentos das pessoas com nível superior encontradas na Pesquisa Nacional por Amostra de Domicílio Contínua (PNAD Contínua) nos anos 2014 e 2015. Daí padrões de amortização são simulados para hipotéticos desenhos de ECR. Os resultados permitem avaliar implicações fiscais e distributivas relacionadas a alguns parâmetros, como taxas de juros, alíquotas e faixas de pagamento. Trata-se de uma avaliação ex ante de uma alternativa para o financiamento estudantil no Brasil perante as restrições fiscais por que passam os orçamentos públicos. Os melhores desenhos, em termos de acessibilidade para graduados e tamanho dos subsídios do contribuinte, envolvem ECRs com sobretaxas de 25% adicionadas aos montantes iniciais dos empréstimos, taxas de juros no nível do custo de financiamento do governo cobradas depois de finalizado o curso, juro real zero durante a fase de estudos e para egressos com renda dentro da faixa de isenção do Imposto de Renda Pessoa Física (IRPF) e taxas progressivas de pagamento alinhadas com as faixas de tributação da renda pessoal e equivalentes à metade das respectivas alíquotas para fins de IRPF.

A short note on determinantal representation of stable polynomials

In this paper we provide some results that replace the condition ”real-zero” by the properties so-called x-substitution and y-substitution. We show that using these properties, we can still write the determinantal representation of a stable polynomial in terms of identity and Hermitian matrices.

P1446Cavo-tricuspid atrial flutter catheter ablation with a real zero fluoroscopic approach

Funding Acknowledgements none Background Catheter ablation(CA)is the first-line therapy of cavo-tricuspid isthmus(CTI)atrial flutter. Sometimes an inversion of ablation catheter is necessary to obtain a complete bidirectional line block. Purpose.The aim of this study was to describe this CA approach using electro-anatomical mapping(EAM)system with a zero-fluoroscopy(ZF)approach.Methods.Ninety-four patients that performed CA of CTI were retrospectively enrolled since 2017 to 2019.The studied population were divided in two groups.Group1(44patients) was composed of patients who underwent CA using ablation catheter without shaft visualization catheter(NSVC)on EAM.Group2(50patients)was composed of patients who underwent CA using ablation catheter with a shaft visualization(SVC). The catheter was looped at the Eustachian ridge after 200 seconds of RF without elimination of local electrogram. Results.ZF CTI ablation was obtained in all patients of group 2 without fluoroscopy use.In six patients of group 1, the catheter inversion was used to obtain a complete CTI block.In NSVC group, the catheter inversion was obtained using fluoroscopy to avoid damages during loop of catheter ablation.In overall population studied SVC had a linear correlation with ZF approach(β=0.629;p < 0.001). No differences were documented regarding acute and late success,complications.The procedural time between two groups was similar (Group1:83.4 ± 22.4 vs.Group2:80.2 ± 34.7minutes). The detailed results were summarize in table1. Conclusions.A real ZF catheter ablation of atrial flutter is safe and feasible.The use of SVC could improve the reproducibility of a successful zero-fluoroscopy CA.The visualization of the shaft’s catheter permit to invert the catheter safely to overcome anatomic complexity of some CTI without fluoroscopy use. detailed results Detailed results Group 1(44 CA) Group 2(50 CA) p value Procedure time (min) 83.4 ± 22.4 80.2 ± 34.7 NS AFL at begin CA (n.) 36 23 FT (min) 9.1 ± 9.8 0 ± 0 < 0.001 PWRF (W) 32 ±2.5 33.6 ±2.2 NS CA line length (mm) 28.1 ± 4.1 27.9 ± 5.5 NS Total RF (min) 27.8 ± 6.3 13.6 ± 7.2 < 0.01 SR during RF 35 23 Conductional block after 30 min 44 50 NS 6 months recurrences 1 1 NS AFL: atrial flutter; FT: fluoroscopy time; PWRF: power radiofrequencies; CA line length: length of line of radiofrequencies; RF: radiofrequencies; SR: sinus rhythm. Detailed results. Abstract Figure.

Systems of polynomials with at least one positive real zero

In this paper, we prove several theorems on systems of polynomials with at least one positive real zero based on the theory of conceive polynomials. These theorems provide sufficient conditions for systems of multivariate polynomials admitting at least one positive real zero in terms of their Newton polytopes and combinatorial structure. Moreover, a class of polynomials attaining their global minimums in the first quadrant are given, which is useful in polynomial optimization.

Bifurcation analysis and frequency prediction in shear-driven cavity flow

A comprehensive study of the two-dimensional incompressible shear-driven flow in an open square cavity is carried out. Two successive bifurcations lead to two limit cycles with different frequencies and different numbers of structures which propagate along the top of the cavity and circulate in its interior. A branch of quasi-periodic states produced by secondary Hopf bifurcations transfers the stability from one limit cycle to the other. A full analysis of this scenario is obtained by means of nonlinear simulations, linear stability analysis and Floquet analysis. We characterize the temporal behaviour of the limit cycles and quasi-periodic state via Fourier transforms and their spatial behaviour via the Hilbert transform. We address the relevance of linearization about the mean flow. Although here the nonlinear frequencies are not very far from those obtained by linearization about the base flow, the difference is substantially reduced when eigenvalues are obtained instead from linearization about the mean and in addition, the corresponding growth rate is small, a combination of properties called RZIF (real zero imaginary frequency). Moreover growth rates obtained by linearization about the mean of one limit cycle are correlated with relative stability to the other limit cycle. Finally, we show that the frequencies of the successive modes are separated by a constant increment.

A Heuristic Method for Certifying Isolated Zeros of Polynomial Systems

In this paper, by transforming the given over-determined system into a square system, we prove a necessary and sufficient condition to certify the simple real zeros of the over-determined system by certifying the simple real zeros of the square system. After certifying a simple real zero of the related square system with the interval methods, we assert that the certified zero is a local minimum of sum of squares of the input polynomials. If the value of sum of squares of the input polynomials at the certified zero is equal to zero, it is a zero of the input system. As an application, we also consider the heuristic verification of isolated zeros of polynomial systems and their multiplicity structures.