Asymptotic symmetries and memories of gauge theories in FLRW spacetimes

In this paper, we investigate the asymptotic structure of gauge theories in decelerating and spatially flat Friedmann-Lema\^itre-Robertson-Walker universes. Firstly, we thoroughly explore the asymptotic symmetries of electrodynamics in this background, which reveals a major inconsistency already present in the flat case. Taking advantage of this treatment, we derive the associated memory effects, discussing their regime of validity and differences with respect to their flat counterparts. Next, we extend our analysis to non-Abelian Yang-Mills, coupling it dynamically and simultaneously to a Dirac spinor and a complex scalar field. Within this novel setting, we examine the possibility of constructing Poisson superbrackets based on the covariant phase space formalism.Comment: 32+9 pages, 2 figure

Uso da abordagem Inbound Marketing em uma empresa de tecnologia com estruturas e estratégias clássicas de marketing

Orientador : Cleverson Renan da CunhaTrabalho de Conclusão de Curso (especialização) - Universidade Federal do Paraná, Setor de Ciências Sociais Aplicadas, Curso de Especialização MBA em Gestão EstratégicaInclui referênciasResumo : O problema em questão está relacionado ao planejamento adequado das estratégias de marketing. Como proporcionar o crescimento do número de leads? Quais as perspectivas de aumento do número de leads com os processos e estruturas existentes hoje? Como se adaptar aos novos conceitos de marketing e incorporá-los à estrutura existente? São para estas e muitas outras perguntas que a empresa deve buscar respostas visando a manutenção e aprimoramento do seu desempenho. O objetivo deste trabalho é identificar alternativas para a otimização do processo de geração de leads a partir da estrutura existente, mas tendo como base o modelo de Inbound Marketing. O problema principal a ser tratado é "Como se utilizar da estrutura existente na empresa para implementar de forma completa a abordagem de Inbound Marketing?". As consequências para a morosidade em um processo de mudança para se adequar às novas técnicas de mercado podem ser enormes e estão diretamente relacionadas à obtenção de leads para o funil de vendas. Impactos neste número se refletem nos resultados financeiros em menos de 8 meses. Como este ciclo é longo, o planejamento é essencial

Asymmetric Interplay Between K+ and Blocker and Atomistic Parameters From Physiological Experiments Quantify K+ Channel Blocker Release

Modulating the activity of ion channels by blockers yields information on both the mode of drug action and on the biophysics of ion transport. Here we investigate the interplay between ions in the selectivity filter (SF) of K+ channels and the release kinetics of the blocker tetrapropylammonium in the model channel KcvNTS. A quantitative expression calculates blocker release rate constants directly from voltage-dependent ion occupation probabilities in the SF. The latter are obtained by a kinetic model of single-channel currents recorded in the absence of the blocker. The resulting model contains only two adjustable parameters of ion-blocker interaction and holds for both symmetric and asymmetric ionic conditions. This data-derived model is corroborated by 3D reference interaction site model (3D RISM) calculations on several model systems, which show that the K+ occupation probability is unaffected by the blocker, a direct consequence of the strength of the ion-carbonyl attraction in the SF, independent of the specific protein background. Hence, KcvNTS channel blocker release kinetics can be reduced to a small number of system-specific parameters. The pore-independent asymmetric interplay between K+ and blocker ions potentially allows for generalizing these results to similar potassium channels

Neural activity in the human anterior thalamus during natural vision

In natural vision humans and other primates explore environment by active sensing, using saccadic eye movements to relocate the fovea and sample different bits of information multiple times per second. Saccades induce a phase reset of ongoing neuronal oscillations in primary and higher-order visual cortices and in the medial temporal lobe. As a result, neuron ensembles are shifted to a common state at the time visual input propagates through the system (i.e., just after fixation). The extent of the brain’s circuitry that is modulated by saccades is not yet known. Here, we evaluate the possibility that saccadic phase reset impacts the anterior nuclei of the thalamus (ANT). Using recordings in the human thalamus of three surgical patients during natural vision, we found that saccades and visual stimulus onset both modulate neural activity, but with distinct field potential morphologies. Specifically, we found that fixation-locked field potentials had a component that preceded saccade onset. It was followed by an early negativity around 50 ms after fixation onset which is significantly faster than any response to visual stimulus presentation. The timing of these events suggests that the ANT is predictively modulated before the saccadic eye movement. We also found oscillatory phase concentration, peaking at 3–4 Hz, coincident with suppression of Broadband High-frequency Activity (BHA; 80–180 Hz), both locked to fixation onset supporting the idea that neural oscillations in these nuclei are reorganized to a low excitability state right after fixation onset. These findings show that during real-world natural visual exploration neural dynamics in the human ANT is influenced by visual and oculomotor events, which supports the idea that ANT, apart from their contribution to episodic memory, also play a role in natural vision

Hexadirectional modulation of high-frequency electrophysiological activity in the human anterior medial temporal lobe maps visual space

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A small viral potassium ion channel with an inherent inward rectification

Some algal viruses have coding sequences for proteins with structural and functional characteristics of pore modules of complex K+ channels. Here we exploit the structural diversity among these channel orthologs to discover new basic principles of structure/function correlates in K+ channels. The analysis of three similar K+ channels with ≤ 86 amino acids (AA) shows that one channel (Kmpv1) generates an ohmic conductance in HEK293 cells while the other two (KmpvSP1, KmpvPL1) exhibit typical features of canonical Kir channels. Like Kir channels, the rectification of the viral channels is a function of the K+ driving force. Reconstitution of KmpvSP1 and KmpvPL1 in planar lipid bilayers showed rapid channel fluctuations only at voltages negative of the K+ reversal voltage. This rectification was maintained in KCl buffer with 1 mM EDTA, which excludes blocking cations as the source of rectification. This means that rectification of the viral channels must be an inherent property of the channel. The structural basis for rectification was investigated by a chimera between rectifying and non-rectifying channels as well as point mutations making the rectifier similar to the ohmic conducting channel. The results of these experiments exclude the pore with pore helix and selectivity filter as playing a role in rectification. The insensitivity of the rectifier to point mutations suggests that tertiary or quaternary structural interactions between the transmembrane domains are responsible for this type of gating

An amino-based protic ionic liquid as a corrosion inhibitor of mild steel in aqueous chloride solutions

Protic ionic liquids (PILs) have shown to be promising substances as corrosion inhibitors (CIs). In line with this, the aim of this study is to study the performance and propose the corrosion inhibition mechanism of N‐methyl‐2‐ hydroxyethylamine (M‐2HEAOL) and bis‐2‐hidroxyethylamine (B‐HEAOL) oleate, for mild steel, in a neutral chloride solution. Electrochemical characterization was conducted under static and hydrodynamic conditions, and it was revealed that M‐2HEAOL and B‐HEAOL worked as mixed‐type CIs with more interference on the anodic reaction. Inhibition efficiency depended on the concentration reaching 97% of inhibition efficiency in 5 mmol/L concentration. Scanning electron microscopy, optical interferometry, Raman spectroscopy, and Fourier‐transform infrared spectroscopy are used to elicit the chemical composition of the surface film and corrosion morphology of steel in the presence of CIs, the adsorption processes of which involved physical and chemical adsorption between metal and different parts of ionic liquids. The results allowed the proposition of a corrosion inhibition mechanism

N-methyl-2-hydroxyethylammonium oleate ionic liquid performance as corrosion inhibitor for mild steel in hydrochloric acid medium

The aim of the present study is to evaluate the performance of N‐methyl‐2‐ hydroxyethylammonium oleate ([m‐2HEA][Ol]) as a corrosion inhibitor for mild steel in a 0.1‐mol/L hydrochloric acid solution and also investigate the role of chloride in the inhibition mechanism. This protic ionic liquid (PIL) has formerly shown a high efficiency as a corrosion inhibitor in a neutral chloride medium. Electrochemical and weight loss measurements, surface contact angle determination, scanning electron microscopy, and Raman spectroscopy were used to understand the factors that influence the response of the studied inhibitor. Results revealed that [m‐2HEA][Ol] behaves as a mixed‐type adsorption inhibitor, by blocking cathodic sites and by modifying the activation energy of the anodic reaction, and it can reach up to 94–97% of inhibition efficiency. PIL adsorption was enhanced by the excess of positive charge of the mild steel. The effect of inhibitor molecule has been discussed to propose a mechanism that explains the inhibitory action of the corrosion inhibitor, pointing out the role of chloride in the inhibition mechanism

Attenuated asthma phenotype in mice with a fetal-like antigen receptor repertoire

We hypothesized that the scarcity of N-nucleotides might contribute to the inability of the neonate to mount a robust allergic immune response. To test this, we used terminal deoxyribunucleotidyl Transferase defcient (TdT−/−) mice, which express “fetal-like” T cell receptor and immunoglobulin repertoires with largely germline-encoded CDR3 regions. Intraperitoneal sensitization was followed by aerosol provocation with either PBS or the allergen OVA in both TdT−/− mice and wild-type mice to develop allergic respiratory infammation. The efects of this procedure were investigated by lung function test, immunological analysis of serum and brochoalveolar lavage. The local TH2 cytokine milieu was signifcantly attenuated in TdT−/− mice. Within this group, the induction of total IgE levels was also signifcantly reduced after sensitization. TdT−/− mice showed a tendency toward reduced eosinophilic infow into the bronchial tubes, which was associated with the elimination of respiratory hyperreactivity. In conclusion, in a murine model of allergic airway infammation, the expression of fetal-like antigen receptors was associated with potent indications of a reduced ability to mount an asthma phenotype. This underlines the importance of somatically-generated antigen-receptor repertoire diversity in type one allergic immune responses and suggests that the fetus may be protected from allergic responses, at least in part, by controlling N addition