# Universidade Federal do ABC (UFABC)

• Santo André, Sao Paulo, Brazil
Recent publications
The signal propagation delay in oscillator networks impairs synchronization, generating oscillatory behavior. These networks use Phase-Locked Loops (PLLs) to synchronize the local oscillator to a reference phase and frequency. The PLLs are widely implemented in data communication and telecommunication systems, as elements (nodes) of time signal distribution. In addition, instrumentation systems and measurement systems, engine speed control, and Atomic Force Microscopy, among others, also use PLLs. The work methodology is based on the implementation of a time signal distribution network with three PLLs, in order to establish a common time basis. The phase detection process generates a periodic oscillation called Double-Frequency Jitter (DFJ). The DFJ is unavoidable appearing even with the PLL operating in the lock-in range. Thus, this chapter aims to study the effect of the double-frequency oscillation in a signal propagation delayed network and its influence on the synchronous states of the network.
Grape pomace (mixture of skins and seeds) is a residual by-product of the winemaking process, rich in polyphenolic compounds that have antioxidant and antimicrobial properties and can be recycled to manufacture fruit extracts to be used in new technological products. The use of non-toxic substances is exciting for developing packagings that are in direct contact with food, as components present in the polymer might migrate to the food. Moreover, the gradual release of these non-toxic bioactive components confers long-term antimicrobial activity to these PP films enriched with grape pomace extract. In addition, the use of raw materials from natural and renewable origins to manufacture antimicrobial packaging contributes to a more sustainable and eco-friendly industrial production and to mitigate environmental impacts. In this research, bactericidal isotactic polypropylene (PP) was developed using grape pomace extract as an antimicrobial additive and presents low water vapor permeability and antimicrobial activity against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria, showing potential to function as an active and safer polymeric food packaging.
We find characterizations of Vašák spaces and weakly K-analytic spaces using the notions of separable projectional resolution of the identity (SPRI) and of projectional skeleton. This in particular addresses a recent challenge suggested by M. Fabian and V. Montesinos in [16]. Our method of proof also gives similar characterizations of WCG spaces and their subspaces (some aspects of which were known, some are new). Moreover we show that for countably many projectional skeletons {sn:n∈ω} on a Banach space inducing the same set, there exists a projectional skeleton on the space (indexed by ranges of the corresponding projections) which is isomorphic to a subskeleton of each sn, n∈ω.
There is a long tradition of studying chaotic trajectories in systems whose integrability is broken by means of an external perturbation. Here we explore a different route to chaos, in the dynamics of extended bodies, which arises due to finite-size corrections to the otherwise integrable motion of a test particle. We find that cyclic changes in the overall shape of the body may lead to the onset of chaos. This is applied to the Duffing and Yukawa potentials. For Kepler’s potential, periodic deviations from spherical symmetry give rise to chaotic regions around the unperturbed parabolic orbit.
The presence of microplastics (MPs) in different terrestrial ecosystems has adverse effects on planet biota and even on humans in the long term. However, few studies evaluate areas with a high circulation of people, such as parks. This work aimed to carry out a comparative study between the municipal landfill and one park in Santo André (SP), Brazil, seeking to prove their presence and establish the types of plastics found in these environments, exploring the correlation between them. For that, different sites at the park were selected, and soil was collected from the surface and 20 cm depth. The samples were characterized by optical microscopy and Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and MPs abundancy and the results were compared with landfill soil as standard. Results indicated the presence of microplastics in the park soil in different morphologies, such as fragments and fibers, and degradation characteristics. The FTIR indicated the presence of polypropylene, polyethylene terephthalate, and polyethylene, with an abundance of 1401 items kg⁻¹ for the park and 2393 items kg⁻¹ in the landfill, indicating that parks have high amounts of MPs in the soil, like landfills, being a source of contaminants with risk of toxicity. This work established a correlation between regions with a higher flow of people and, consequently, more significant maintenance and cleaning, with a lower frequency of microplastics, and regions with a lower flow of people, such as places with more vegetation, where the incorrect disposal of solid waste results in a higher frequency of microplastics with characteristics of degradation by weathering.
Background: The COVID-19 situation in Brazil is complex due to large differences in the shape and size of regional epidemics. Understanding these patterns is crucial to understand future outbreaks of SARS-CoV-2 or other respiratory pathogens in the country. Methods: We tested 97,950 blood donation samples for IgG antibodies from March 2020 to March 2021 in eight of Brazil's most populous cities. Residential postal codes were used to obtain representative samples. Weekly age- and sex- specific seroprevalence was estimated by correcting the crude seroprevalence by test sensitivity, specificity and antibody waning. Results: The inferred attack rate of SARS-CoV-2 in December 2020, before the Gamma VOC was dominant, ranged from 19.3% (95% CrI 17.5% - 21.2%) in Curitiba to 75.0% (95% CrI 70.8% - 80.3%) in Manaus. Seroprevalence was consistently smaller in women and donors older than 55 years. The age-specific infection fatality rate (IFR) differed between cities and consistently increased with age. The infection hospitalisation rate (IHR) increased significantly during the Gamma-dominated second wave in Manaus, suggesting increased morbidity of the Gamma VOC compared to previous variants circulating in Manaus. The higher disease penetrance associated with the health system's collapse increased the overall IFR by a minimum factor of 2.91 (95% CrI 2.43 - 3.53). Conclusions: These results highlight the utility of blood donor serosurveillance to track epidemic maturity and demonstrate demographic and spatial heterogeneity in SARS-CoV-2 spread. Funding: This work was supported by Itaú Unibanco 'Todos pela Saude' program; FAPESP (grants 18/14389-0, 2019/21585-0); Wellcome Trust and Royal Society Sir Henry Dale Fellowship 204311/Z/16/Z; the Gates Foundation (INV- 034540 and INV-034652); REDS-IV-P (grant HHSN268201100007I); the UK Medical Research Council (MR/S0195/1, MR/V038109/1); CAPES; CNPq (304714/2018-6); Fundação Faculdade de Medicina; Programa Inova Fiocruz-CE/Funcap - Edital 01/2020 Number: FIO-0167-00065.01.00/20 SPU Nº06531047/2020; JBS - Fazer o bem faz bem.
A classical theorem due to Chebyshev, Markov and Stieltjes states that the Gauss-Legendre quadrature of a generic function f is a Riemann sum of f. In this note we prove an analogue of this theorem for Romberg quadrature.
Objective: evaluate the influence of participation in cycles of the ALI Program in the innovative ambience of Medicatriz Dermocosmetics from 2013 to 2020. Investigated context: the basis of the ALI Program methodology was defined by eight premises: concrete results; use of indicators; results for Sebrae and the innovation ecosystem; involvement of the company's team; collective construction of solutions; tools; companies motivated to innovate; and ALI as a facilitator to overcome the dilemma of having a good creative potential, but without converting into innovations that provide increased sales. Intervention: adopt mechanisms to solve the diagnosed problems, some interventions of open innovation, co-creation, branding, ethnographic research, current customer, and employee satisfaction were proposed for each cycle of participation. Results: in the first cycle, eleven new products were launched using nanotechnology and sensory transversality; in the second, there was a sub-category of customers and humanized projects for customers, employees, and social circles; in the third, remodeling of workshops, creation of paid courses, school visits, supervised internship, and advanced support; and in the fourth, a model for recognizing employees was created. Conclusion: the promotion of the continued practice of innovation actions in small companies and contributions to Medicatriz permeated the four dimensions of innovation. The company understands that investment in human development increases the chances of organizations becoming productive and engaging for their employees, suppliers, and customers.
We revisit in this note the Hénon’s isochrone problem. By using the standard Abel inversion technique for one-dimensional motion, we recover in a simple way the Hénon’s parabolae and get all isochrone central potentials under mild smoothness assumptions on the potential function. Our approach also allows us to conclude that isochronous radial periods with explicit energy dependence are necessarily Keplerian, i.e., T<sup>2</sup> ∝ |E|<sup>−3</sup>, and that their corresponding orbits can be easily integrated by mapping them into the usual Kepler problem. It can also be employed to study some
We consider a general quantum field relativistic scattering involving two half-spin fermions, A and B, which are initially entangled with another fermion C that does not participate in the scattering dynamics. We construct general expressions for the reduced spin matrices for the out-state considering a general tripartite spin-entangled state. In particular we study an inelastic QED process at tree-level, namely e−e+→μ−μ+ and a half-spin fermion C as a spectator particle which can be entangled to the AB system in the following ways: W state, GHZ state, |Aα⟩⊗|Ψ±⟩BC, and |Aα⟩⊗|Φ±⟩BC, where {|Ψ±⟩,|Φ±⟩} are the Bell basis states and |Aα⟩ is a spin superposition state of system A. We calculate the von Neumann entropy variation before and after the scattering for the particle C and show that spin measurements in C contain numerical information about the total cross section of the process. We compare the initial states W and GHZ as well as study the role played by the parameter α in the evaluation of the entropy variations and the cross section encoded in the spectator particle.
Abstract This article aims to present the Marxist theoretical framework based on Nicos Poulantzas’s thought to analyse regionalism in Latin America. We propose that regionalism is determined by the interests of the bourgeois hegemonic fraction in the power bloc. The originality of the theoretical proposal presented lies in the thesis that regionalisms are the fruit of relations between power blocs of the member states. The article illustrates the recent processes of regionalism in Latin America that, from this theoretical proposal’s point of view, can vary among the following models: open regionalism (related to the interests of comprador bourgeoisie); multidimensional regionalism (linked to internal bourgeoisie interests); and anti-imperialism (related to a national bourgeoisie project). We conclude that the dependency of these social formations, the presence of foreign capital, and the role of US imperialism should be considered in the analysis of regionalism in Latin America.
Neste artigo discute-se o experimento seminal de Gleb Wataghin e seus jovens assistentes Marcelo Damy de Souza Santos e Paulus Aulus Pompéia em que foi detectado um componente inesperado de partículas capazes de atravessar dezenas de centímetros de chumbo (os chuveiros penetrantes), explorando as conexões entre o cenário brasileiro da época e os desenvolvimentos posteriores da física moderna. São ainda descritos os trabalhos de Wataghin na USP sobre raios cósmicos no período de 1939 a 1949, considerando a influência recíproca de Wataghin e Heisenberg na busca da solução para o problema das divergências da Eletrodinâmica Quântica (QED), na introdução de comprimento universal mínimo e, principalmente, na consolidação da hipótese da produção múltipla das partículas geradas na colisão dos raios cósmicos com a atmosfera.
Asphaltenes are a severe problem for the oil industry. The high content of aromatic and aliphatic hydrocarbons in asphaltenes poses a challenge for efficient methods of the solubilization and degradation of their components. The main goal of this study was to investigate an efficient and innovative method for asphaltene solubilization with surfactants to produce supramolecular aggregates with affinity by magnetic nanoparticles (Fe3O4) for magnetic separation and degradation. Asphaltene mixed with the cationic surfactant cetyltrimethylammonium bromide (CTAB) was both solubilized in chloroform and the solvent dried with N2 to produce a film that was resuspended in water and formed a stable colloid with asphaltene incorporated in CTAB micelles. The suspensions of CTAB/asphaltene supramolecular aggregates obtained at different surfactant/asphaltene ratios were characterized by dynamic and static light scattering (DLS and SLS) and by electrophoretic mobility for ζ potential determination. CTAB concentrations of 30 and 60 mM produced spherical supramolecular aggregates (SMAs) of size between 100 and 200 nm with polydispersity. The ζ potential of CTAB micelles loaded with asphaltenes increased from +9.17 +/− 4.6 to +56.7 +/− 5.8 eV. Electron paramagnetic resonance revealed that asphaltene forms stable free radicals in CTAB micelles. Classical molecular dynamics simulations were also used to study interactions of the functional groups of asphaltenes. The association with CTAB micelles provided the binding affinity of asphaltenes for nanoparticulate magnetite (Fe3O4) and precipitation of the most CTAB content. In this condition, Fe3O4 promoted the degradation of asphaltenes to low molecular mass products. Therefore, incorporation in CTAB micelles is a simple and innovative method contributing to asphaltene removal, degradation, and possible conversion to products with aggregated value.
The perils of climate change turn the definition of conservation areas into an urgent task. With finite financial resources, we must choose efficiently what and where to prioritize. Here, we discuss the benefits of using three parameters - species richness, functional and phylogenetic diversity - to subsidize the proposal of conservation areas complementary to those already existing in Southern South America and New Zealand. The parameters were defined using museum specimens and available taxonomic registers for three genera of craneflies: Aphrophila , Zelandomyia , and Amphineurus ( Rhamphoneurus ). We found additional priority conservation areas for New Zealand and Southern South America based on maximized species richness, phylogenetic and functional diversity of Aphrophila , Amphineurus ( Rhamphoneurus ), and Zelandomyia . We plotted the new areas into maps presenting the current conservation areas to compare them. We advocate utilizing all available information on biodiversity for conservation initiatives, including data stored in museums. New Zealand and Southern South America are examples of how dealing with multiple parameters, including criteria that take evolutionary history and species ecology into account, may lead to reliable proposals of priority conservation areas.
Determining the biochemical methane potential (BMP) is an important step in the study of anaerobic digestion of sugarcane vinasse before the implementation of a full scale bioreactor. However, the compositional analysis and the evaluation of different food-to-microorganism ratio to avoid underestimating the BMP of vinasse have not been extensively used in BMP assays. Consequently, the study of the literature revealed differences between vinasse BMPs where the food-microorganism ratio used was the standardized, probably because this factor does not reflect the impact of the vinasse compositional variability on its BMP. Thus, the present research aimed to optimize the food-microorganism ratio to maximize the BMP of a mixed origin vinasse and compare it with the literature. Through a multifactorial experimental design associated with the Response Surface Methodology, the BMP of the vinasse was maximized by increasing the food-to-microorganism ratio. The most significative factor in this study was the increase of vinasse concentration in the BMP test. A conversion efficiency to methane achieved was 95 ± 2.55% compared to the theoretical BMP, with a food-to-microorganism ratio between 1.34 and 1.42 gSCOD·g −1 VSS. Therefore, the results of this investigation demonstrated that the BMP of vinasse can be maximized by optimizing the food-microorganism ratio. It is not recommended to standardize this parameter for sugarcane vinasse due to its high compositional variability.
Although numerous studies about camouflage have been conducted in the last few decades, there is still a significant gap in our knowledge about the magnitude of protective value of different camouflage strategies in prey detection and survival. Furthermore, the functional significance of several camouflage strategies remains controversial. Here we carried out a comprehensive meta-analysis including comparisons of different camouflage strategies as well as predator and prey types, considering two response variables: mean predator search time (ST) (63 studies) and predator attack rate (AR) of camouflaged prey (28 studies). Overall, camouflage increased the predator ST by 62.56% and decreased the AR of prey by 27.34%. Masquerade was the camouflage strategy that most increased predator ST (295.43%). Background matching and disruptive coloration did not differ from each other. Motion camouflage did not increase ST but decreases AR on prey. We found no evidence that eyespot increases ST and decreases AR by predators. The different types of predators did not differ from each other, but caterpillars were the type of prey that most influenced the magnitude of camouflage's effect. We highlight the potential evolutionary mechanisms that led camouflage to be a highly effective anti-predatory adaptation, as well as potential discrepancies or redundancies among strategies, predator and prey types.
We present integral, differential, and momentum transfer cross sections for elastic electron collisions with the two most stable isomers of the B2H4 molecule, hereafter referred to as isomer I (C2v symmetry) and isomer II (D2d symmetry), and with the B2H6 molecule (D2h symmetry). The isomer I of B2H4 and the B2H6 molecule are known for their electrodeficiency in the “three-center two-electron” (3c–2e) bond, a region in which a hydrogen atom occupies a bridged position between two non-hydrogen atoms. The cross sections were computed by using the Schwinger multichannel method implemented with norm-conserving pseudopotentials, and the scattering calculations were carried out in the static-exchange and static-exchange plus polarization levels of approximation for energies from 0.1 to 50 eV. We discuss the presence of shape resonances in the scattering cross sections. We also made a direct comparison among the cross sections of these three targets.
The search for new prominent chemosensors is significantly related to the rationalization of possible multiple pathways of excited-state deactivation. We have prepared and studied compound α-(2-hydroxyphenyl)-N-phenylnitrone (Nit-OH), observing that Nit-OH is stable in acetonitrile solution under UV-vis light. The experimentally observed 540 nm fluorescence for Nit-OH was shown to be related to excitation at 360 nm from the highest occupied molecular orbital to the lowest unoccupied molecular orbital (HOMO-LUMO transition). Potential energy curves (PECs) for the S1 state of Nit-OH did show that there are structures associated with excited-state intramolecular proton transfer (ESIPT), and the existence of an intramolecular H-bonding was confirmed using X-ray powder diffraction (XRD). Twisted intramolecular charge transfer (TICT) took place following ESIPT, and a nonradiative deactivation at the S1/S0 conical intersection occurred; aggregation-induced emission was observed at 540 nm associated with the formation of a stacked dimer. Anti-Kasha emission from the S2 was proposed based on the dependence of the fluorescence excitation wavelength on Nit-OH concentration. From the calculation of the PEC for the S2 state, we obtained radiative transitions at 379 and 432 nm, similar to the obtained experimental values of 383 and 453 nm. We proposed a Jablonski-like diagram that depicts all experimental and theoretical electronic transitions for Nit-OH, summarizing the unique intricate photophysical behavior of this nitrone derivative.
Objective: The diagnosis of nerve disorders in humans has relied heavily on the measurement of electrical signals from nerves or muscles in response to electrical stimuli applied at appropriate locations on the body surface. The present study investigated the demyelinating subtype of Guillain-Barré syndrome using multiscale computational model simulations to verify how demyelination of peripheral axons may affect plantar flexion torque as well as the ongoing electromyogram (EMG) during voluntary isometric or isotonic contractions. Approach: Changes in axonal conduction velocities, mimicking those found in patients with the disease at different stages, were imposed on a multiscale computational neuromusculoskeletal model to simulate subjects performing unipodal plantar flexion force and position tasks. Main results: The simulated results indicated changes in the torque signal during the early phase of the disease while performing isotonic tasks, as well as in torque variability after partial conduction block while performing both isometric and isotonic tasks. Our results also indicated changes in the root mean square values and in the power spectrum of the soleus EMG signal as well as changes in the synchronisation index computed from the firing times of the active motor units. All these quantitative changes in functional indicators suggest that the adoption of such additional measurements, such as torques and ongoing EMG, could be used with advantage in the diagnosis and be relevant in providing extra information for the neurologist about the level of the disease. Significance: Our findings enrich the knowledge of the possible ways demyelination affects force generation and position control during plantarflexion. Moreover, this work extends computational neuroscience to computational neurology and shows the potential of biologically compatible neuromuscular computational models in providing relevant quantitative signs that may be useful for diagnosis in the clinic, complementing the tools traditionally used in neurological electrodiagnosis.
This article describes the setup and performance of the near and far detectors in the Double Chooz experiment. The electron antineutrinos of the Chooz nuclear power plant were measured in two identically designed detectors with different average baselines of about 400 m and 1050 m from the two reactor cores. Over many years of data taking the neutrino signals were extracted from interactions in the detectors with the goal of measuring a fundamental parameter in the context of neutrino oscillation, the mixing angle $$\theta _{13}$$ θ 13 . The central part of the Double Chooz detectors was a main detector comprising four cylindrical volumes filled with organic liquids. From the inside towards the outside there were volumes containing gadolinium-loaded scintillator, gadolinium-free scintillator, a buffer oil and, optically separated, another liquid scintillator acting as veto system. Above this main detector an additional outer veto system using plastic scintillator strips was installed. The technologies developed in Double Chooz were inspiration for several other antineutrino detectors in the field. The detector design allowed implementation of efficient background rejection techniques including use of pulse shape information provided by the data acquisition system. The Double Chooz detectors featured remarkable stability, in particular for the detected photons, as well as high radiopurity of the detector components.
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