1,410 research outputs found
Design of High-Bandwidth and High-Linearity Input Buffers for ADCs
Nowadays on-chip Input Buffers (IBs) for direct conversion front-ends are realized
with a higher voltage supply than that of the core voltage of the technology, mainly for
linearity purposes. This, in turn, makes it mandatory to have more than one voltage
source to supply a single chip in addition to having devices capable of handling higher
voltages.
This work explores the possibility of having IBs supplied with the technology’s core
voltage to standardize all of the devices and reducing the different voltage supply sources
and/or voltage regulators needed for operating the front-end drivers of the Analog to
Digital Converters (ADCs).
A new input buffer architecture will be presented and compared to some prior input
buffer implementations in the same conditions. This new architecture presents good
linearity and bandwidth results and can be used for input buffers with the added benefit
of not needing higher voltages nor special devices.
This new architecture is based off an existing one with another feedback loop to
improved high-frequency peaking and linearity issues. This architecture achieves better
results in bandwidth, a SNDR of 58 dB with and output voltage of 600 mV peak-to-peak
differential. Furthermore, this buffer achieves a better efficiency linearity-wise when
comparing to other buffers in the same conditions
Analyse the influence that music has on students’ concentration levels.
This project aims to present the influence that music has on concentration levels while studying. It will present the results of some experiments that have been developed by specialists, specifically to measure the performance of students with and without music. It will also be presented how the music industry can benefit from it financially
Contextuality in the Integrated Information Theory
Integrated Information Theory (IIT) is one of the most influential theories of consciousness, mainly due to its claim of mathematically formalizing consciousness in a measurable way. However, the theory, as it is formulated, does not account for contextual observations that are crucial for understanding consciousness. Here we put forth three possible difficulties for its current version, which could be interpreted as a trilemma. Either consciousness is contextual or not. If contextual, either IIT needs revisions to its axioms to include contextuality, or it is inconsistent. If consciousness is not contextual, then IIT faces an empirical challenge. Therefore, we argue that IIT in its current version is inadequate
Dissolved humic substances supplied as potential enhancers of Cu, Cd, and Pb adsorption by two different mangrove sediments
Purpose The external supply of humic substances has been recently suggested for the remediation of metal-polluted sediments; however, little is known about how to supply them and their effects on metal mobility. The study sought to investigate the sediment\u2014metals\u2014humic substance interaction in mangrove forest sediments. We aimed to evaluate the sediment adsorption potential in the case of large and rapid metal loads, as recently occurred in the Doce River (Brazil).
Materials and methods In each mangrove forest sampling point of the Benevente River (RB) and Vitoria bay (MO), sediments were collected randomly along the river banks at a depth of 0\u201310 cm. Samples were characterized in terms of pH, CEC, organic carbon, texture, specific surface area, and elemental composition. The heavy metal content was measured by mass absorption spectrophotometry. Humic substances were extracted from the sediments according to the International Humic Substances Society (IHSS) method, avoiding separation of fulvic and humic acids. Original sediments were supplemented with humic substances and six Cu, Cd, or Pb concentrations. Freundlich and Langmuir equations were employed to create adsorption isotherms.
Results and discussion The two sediments are significantly different, specifically with regard to organic carbon and Fe content, texture, and specific surface area. External humic substances increased the Cu adsorption capacity in both sediments but without an important change in Cu adsorption dynamics. Humic substances slightly increased the sediment adsorption capacity of Pb in RB sediment while they decreased in MO sediment, characterized by lower specific surface area, probably due to coverage of the active adsorption sites. Cd isotherms showed that the different characteristics of sediments alone do not affect Cd adsorption, but coupled with humic substances; Cd affinity for the soil surface increased five times in RB sediments confirming sediment-metal- humic substance interactions.
Conclusions Humic substances affect soil metal retention mainly by altering the ion affinity for sediment surface, leading to contrasting results. The Fe concentration could be important depending on specific surface area and humic substance percentage, due to its capacity to form spheroids linked to molecules of humic substances on the clay surface. Several works have been carried out on this research area, but due to the many variables and different metal ions, we recommend further studies
Field record of aestivation with formation of cocoon in the frog Leptodactylus fuscus (Anura: Leptodactylidae) in a semiarid region of northeastern Brazil
Design of a new molecularly imprinted polymer selective for hydrochlorothiazide based on theoretical predictions using gibbs free energy
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A molecularly imprinted polymer (MIP) for the diuretic drug hydrochlorothiazide (HCTZ) based on theoretical predictions was developed. Molecular modeling calculations were performed to study the intermolecular interactions in the pre-polymerization mixture and to select a suitable functional monomer and a porogenic solvent for the synthesis of the MIP. To confirm the results of the theoretical predictions, three MIPs were synthesized and evaluated using the equilibrium batch rebinding method. A water-compatible MIP was prepared using HCTZ as the template and acrylamide as the functional monomer (FM) with ethylene glycol dimethacrylate as the cross-linker and tetrahydrofuran as the porogen. An imprinting factor of 8.24 was obtained. The polymer was characterized by Fourier transform infrared (FTIR), solid-state nuclear magnetic resonance, scanning electron microscopy, thermogravimetric analysis and nitrogen sorption porosimetry. In addition to HCTZ, six structurally related compounds were tested to evaluate the selectivity of the HCTZ-MIP, and cross-selectivity of the MIP was verified.A molecularly imprinted polymer (MIP) for the diuretic drug hydrochlorothiazide (HCTZ) based on theoretical predictions was developed. Molecular modeling calculations were performed to study the intermolecular interactions in the pre-polymerization mixtur271223002311FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)2007/02306-9141618/2010-8The authors gratefully acknowledge financial support from CNPq (141618/2010-8), FAPESP (2007/02306-9) and FAEPEX-UNICAM
Innovation in the pandemic: the actions of the Federal University of Mato Grosso do Sul to guarantee the rights of the university community
The Federal University of Mato Grosso do Sul (UFMS), in order to meet the United Nations Sustainable Development Goals and guarantee the constitutional rights to health and higher education of its university students, adopted innovative initiatives during the Covid-19 pandemic, allowing the maintenance of academic and administrative activities. With the emergency remote teaching for students and home office for servers, emergency aid for digital inclusion was made available, such as costing internet packages, mobile data chip distribution, electronic equipment loan, financing of personal protective equipment and installation of internet via radio in villages for indigenous students. Professors were offered training courses on information and communication technology tools and innovative methodologies for remote teaching. Furthermore, UFMS offered free molecular testing and diagnosis of Sars-Cov-2 to members of the academic community of Cidade Universitária who presented symptoms of Covid-19. All these actions carried out by UFMS, besides highlighting it on the national scene, made it possible to complete the 2020 academic calendar within the same year, an achievement that took place only in two other Brazilian federal universities.Keyword: Innovation in the pandemic. Right to education. Right to health. Digital inclusion. Sustainable Development Goal
Democracia deliberativa em sociedades multiculturais: os desafios da legitimidade e da autodeterminação
o livro resenhado apresenta os dilemas enfrentados pelas democracias liberais multiculturais em face da presença de grupos etnoculturais diversos dentro das fronteiras dos estados nacionais. Partindo da ideia de que a democracia deliberativa é o modelo normativo ideal mais adequado para promover um diálogo político consequente entre estes grupos e a sociedade dominante, a obra promove uma vigorosa crítica de conceitos centrais da filosofia política moderna. Na sequência, as discussões constroem uma vigorosa defesa da participação dos grupos minoritários no maior número de espaços de poder em uma dada sociedade. Suas conclusões fundamentais compreendem que apenas um vigoroso investimento na educação intercultural, na consciência ecológica e na construção de redes de engajamento cívico robustas pode resultar em sociedades políticas mais capazes de processar suas demandas e aptas a diminuir as iniquidades históricas construídas ao longo dos séculos
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