O princípio da segurança jurídica como limitador do poder de tributar do Estado brasileiro e a proteção aos direitos fundamentais

O presente artigo tem por objetivo o estudo do princípio da segurança jurídica, sob o viés da certeza do direito, como forma de limitação ao poder de tributar do estado brasileiro e de proteção aos direitos fundamentais. Ante os vários conteúdos que podem ser depreendidos do princípio da segurança jurídica, a pesquisa em tela procurou dar um enfoque ao conteúdo da certeza do direito, que se perfectibiliza por meio da aplicação dos princípios constitucionais tributários da legalidade, da irretroatividade e da anterioridade. Por meio de pesquisa doutrinária e jurisprudencial, com relação ao princípio da legalidade, observou-se que a edição de Medidas Provisórias, em matéria tributária, além de violar o mencionado princípio, traz insegurança jurídica aos contribuintes. No que tange ao princípio da irretroatividade, verificou-se que a aplicação da Súmula nº 584, do Supremo Tribunal Federal, ofende sobremaneira o princípio da irretroatividade, trazendo insegurança jurídica aos contribuintes. Por fim, no que atine ao princípio da anterioridade, constatou-se que a prorrogação de tributos, sem a observância do princípio em comento, causa, igualmente, enorme insegurança jurídica aos contribuintes. Nessa conjuntura, procurou-se demonstrar a importância do estudo do princípio da segurança jurídica sob o viés da certeza do direito para a efetiva defesa dos contribuintes, haja vista que estes necessitam planejar e organizar sua vida financeira de acordo com os tributos previstos em lei, sabedores de que tais leis não atingirão fatos passados e que será observado o lapso temporal estipulado na Constituição Federal para o início da eficácia dessas leis. Palavras-chave: Poder de tributar. Direitos fundamentais. Princípios. Segurança jurídica. Certeza do direito. THE PRINCIPLE OF LEGAL SECURITY AS LIMITING TO THE TAXING POWER OF THE BRAZILIAN STATE AND THE PROTECTION OF FUNDAMENTAL RIGHTS ABSTRACT This article aims to study the principle of legal security, under the bias of legal certainty, as a way of limiting the taxing power of the Brazilian state and the protection of fundamental rights. In view of the various contents that can be gathered from the principle of legal security, the research sought to provide a focus on the content of legal certainty, which perfects itself through the application of constitutional principles of taxation of legality, non-retroactivity and precedence. By way of doctrinal and jurisprudential research, regarding the principle of legality, it was observed that the issue of Provisional Measures, concerning tax matters, in addition to violating the mentioned principle, brings legal uncertainty to taxpayers. With respect to the principle of non-retroactivity, it was found that the application of Summula No. 584, the Supreme Court, greatly offends the principle of non-retroactivity, bringing legal uncertainty to taxpayers. Finally, as to the principle of precedence, it was found that the extension of taxes, without the observance of the principle under discussion, causes, likewise, enormous legal uncertainty to taxpayers. In this conjuncture, we tried to demonstrate the importance of studying the principle of legal security under the bias of legal certainty for the effective defence of taxpayers, given that they need to plan and organize their financial lives according to the taxes provided by law, knowing that such laws do not reach past events and will be subject to the time lapse stipulated in the Federal Constitution to the beginning of the effectiveness of these laws. Keywords: Taxing power. Fundamental rights. Principles. Legal security. Legal certainty. Data de submissão: 28/01/2015 Data de aceitação: 12/05/201

Kaon decays and the flavour problem

After a brief introduction to the so-called flavour problem, we discuss the role of rare K decays in probing the mechanism of quark-flavour mixing. Particular attention is devoted to the formulation of the Minimal Flavour Violation hypothesis, as a general and natural solution to the flavour problem, and to the fundamental role of K -> pi nu nu-bar decays in testing this scenario.Comment: 10 pages, 6 figures, contribution to TH 2002 (Paris, July 2002

Charged-Higgs phenomenology in the Aligned two-Higgs-doublet model

The alignment in flavour space of the Yukawa matrices of a general two-Higgs-doublet model results in the absence of tree-level flavour-changing neutral currents. In addition to the usual fermion masses and mixings, the aligned Yukawa structure only contains three complex parameters, which are potential new sources of CP violation. For particular values of these three parameters all known specific implementations of the model based on discrete Z_2 symmetries are recovered. One of the most distinctive features of the two-Higgs-doublet model is the presence of a charged scalar. In this work, we discuss its main phenomenological consequences in flavour-changing processes at low energies and derive the corresponding constraints on the parameters of the aligned two-Higgs-doublet model.Comment: 46 pages, 19 figures. Version accepted for publication in JHEP. References added. Discussion slightly extended. Conclusions unchange

Light Stop Decay in the MSSM with Minimal Flavour Violation

In supersymmetric scenarios with a light stop particle $\tilde{t}_1$ and a small mass difference to the lightest supersymmetric particle (LSP) assumed to be the lightest neutralino, the flavour changing neutral current decay $\tilde{t}_1 \to c \tilde{\chi}_1^0$ can be the dominant decay channel and can exceed the four-body stop decay for certain parameter values. In the framework of Minimal Flavour Violation (MFV) this decay is CKM-suppressed, thus inducing long stop lifetimes. Stop decay length measurements at the LHC can then be exploited to test models with minimal flavour breaking through Standard Model Yukawa couplings. The decay width has been given some time ago by an approximate formula, which takes into account the leading logarithms of the MFV scale. In this paper we calculate the exact one-loop decay width in the framework of MFV. The comparison with the approximate result exhibits deviations of the order of 10% for large MFV scales due to the neglected non-logarithmic terms in the approximate decay formula. The difference in the branching ratios is negligible. The large logarithms have to be resummed. The resummation is performed by the solution of the renormalization group equations. The comparison of the exact one-loop result and the tree level flavour changing neutral current decay, which incorporates the resummed logarithms, demonstrates that the resummation effects are important and should be taken into account.Comment: 29 page

Strong interface-induced spin-orbit coupling in graphene on WS2

Interfacial interactions allow the electronic properties of graphene to be modified, as recently demonstrated by the appearance of satellite Dirac cones in the band structure of graphene on hexagonal boron nitride (hBN) substrates. Ongoing research strives to explore interfacial interactions in a broader class of materials in order to engineer targeted electronic properties. Here we show that at an interface with a tungsten disulfide (WS2) substrate, the strength of the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The induced SOI leads to a pronounced low-temperature weak anti-localization (WAL) effect, from which we determine the spin-relaxation time. We find that spin-relaxation time in graphene is two-to-three orders of magnitude smaller on WS2 than on SiO2 or hBN, and that it is comparable to the intervalley scattering time. To interpret our findings we have performed first-principle electronic structure calculations, which both confirm that carriers in graphene-on-WS2 experience a strong SOI and allow us to extract a spin-dependent low-energy effective Hamiltonian. Our analysis further shows that the use of WS2 substrates opens a possible new route to access topological states of matter in graphene-based systems.Comment: Originally submitted version in compliance with editorial guidelines. Final version with expanded discussion of the relation between theory and experiments to be published in Nature Communication

Analysis of techni-dilaton as a dark matter candidate

The almost conformal dynamics of walking technicolor (TC) implies the existence of the approximate scale invariance, which breaks down spontaneously by the condensation of anti-techni and techni-fermions. According to the Goldstone theorem, a spinless, parity-even particle, called techni-dilaton (TD), then emerges at low energy. If TC exhibits an extreme walking, TD mass is parametrically much smaller than that of techni-fermions (around 1 TeV), while its decay constant is comparable to the cutoff scale of walking TC. We analyze the light, decoupled TD as a dark matter candidate and study cosmological productions of TD, both thermal and non-thermal, in the early Universe. The thermal population is governed dominantly by single TD production processes involving vertices breaking the scale symmetry, while the non-thermal population is by the vacuum misalignment and is accumulated via harmonic and coherent oscillations of misaligned classical TD fields. The non-thermal population turns out to be dominant and large enough to explain the abundance of presently observed dark matter, while the thermal population is highly suppressed due to the large TD decay constant. Several cosmological and astrophysical limits on the light, decoupled TD are examined to find that the TD mass is constrained to be in a range between 0.01 eV and 500 eV. From the combined constraints on cosmological productions and astrophysical observations, we find that the light, decoupled TD can be a good dark matter candidate with the mass around a few hundreds of eV for typical models of (extreme) walking TC. We finally mention possible designated experiments to detect the TD dark matter.Comment: 26 pages. 16 figures; v2, expanded Section 2.4 on composite Higgs in light of newly discovered Higgs-like particle at LH

Plasmodium falciparum Adhesion on Human Brain Microvascular Endothelial Cells Involves Transmigration-Like Cup Formation and Induces Opening of Intercellular Junctions

Cerebral malaria, a major cause of death during malaria infection, is characterised by the sequestration of infected red blood cells (IRBC) in brain microvessels. Most of the molecules implicated in the adhesion of IRBC on endothelial cells (EC) are already described; however, the structure of the IRBC/EC junction and the impact of this adhesion on the EC are poorly understood. We analysed this interaction using human brain microvascular EC monolayers co-cultured with IRBC. Our study demonstrates the transfer of material from the IRBC to the brain EC plasma membrane in a trogocytosis-like process, followed by a TNF-enhanced IRBC engulfing process. Upon IRBC/EC binding, parasite antigens are transferred to early endosomes in the EC, in a cytoskeleton-dependent process. This is associated with the opening of the intercellular junctions. The transfer of IRBC antigens can thus transform EC into a target for the immune response and contribute to the profound EC alterations, including peri-vascular oedema, associated with cerebral malaria

Clinical chronobiology: a timely consideration in critical care medicine

A fundamental aspect of human physiology is its cyclical nature over a 24-h period, a feature conserved across most life on Earth. Organisms compartmentalise processes with respect to time in order to promote survival, in a manner that mirrors the rotation of the planet and accompanying diurnal cycles of light and darkness. The influence of circadian rhythms can no longer be overlooked in clinical settings; this review provides intensivists with an up-to-date understanding of the burgeoning field of chronobiology, and suggests ways to incorporate these concepts into daily practice to improve patient outcomes. We outline the function of molecular clocks in remote tissues, which adjust cellular and global physiological function according to the time of day, and the potential clinical advantages to keeping in time with them. We highlight the consequences of "chronopathology", when this harmony is lost, and the risk factors for this condition in critically ill patients. We introduce the concept of "chronofitness" as a new target in the treatment of critical illness: preserving the internal synchronisation of clocks in different tissues, as well as external synchronisation with the environment. We describe methods for monitoring circadian rhythms in a clinical setting, and how this technology may be used for identifying optimal time windows for interventions, or to alert the physician to a critical deterioration of circadian rhythmicity. We suggest a chronobiological approach to critical illness, involving multicomponent strategies to promote chronofitness (chronobundles), and further investment in the development of personalised, time-based treatment for critically ill patients