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Wyszukujesz frazę "Oliveira, L." wg kryterium: Autor


Tytuł:
The influence of aging on the isometric torque sharing patterns among the plantar flexor muscles
Autorzy:
Oliveira, L. F.
Verneque, D.
Menegaldo, L. L.
Powiązania:
https://bibliotekanauki.pl/articles/306726.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
starzenie się
EMG
zgięcie podeszwowe
mięsień trójgłowy łydki
aging
triceps surae
plantar flexion
torque sharing
Opis:
Purpose: Physiological cross-sectional area (PCSA) reduction of the triceps surae (TS) muscles during aging suggests a proportional loss of torque among its components: soleus, medial and lateral gastrocnemii. However, direct measurements of muscle forces in vivo are not feasible. The purpose of this paper was to compare, between older and young women, isometric ankle joint torque sharing patterns among TS muscles and tibialis anterior (TA). Methods: An EMG-driven model was used for estimating individual muscle torque contributions to the total plantar flexor torque, during sustained contractions of 10% and 40% of maximum voluntary contraction (MVC). Results: Relative individual muscle contributions to the total plantar flexion torque were similar between older and young women groups, for both intensities, increasing from LG, MG to SOL. Muscle strength (muscle torque/body mass) was significantly greater for all TS components in 40% MVC contractions. Increased TA activation was observed in 10% of MVC for older people. Conclusions: Despite the reduced maximum isometric torque and muscle strength, the results suggest small variations of ankle muscle synergies during the aging process.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 1; 41-45
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and design of a MOSFET-only wideband balun LNA
Autorzy:
Bastos, I.
Oliveira, L. B.
Goes, J.
Silva, M.
Powiązania:
https://bibliotekanauki.pl/articles/397861.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
tranzystor polowy MOS-tylko obwody
redukcja hałasu
CMOS LNAs
MOSFET-only circuits
noise cancelling
wideband LNA
Opis:
In this paper we present a MOSFET-only implementation of a balun LNA. This LNA is based on the combination of a common-gate and a common-source stage with cancellation of the noise of the common-gate stage. In this circuit, we replace resistors by transistors, to reduce area and cost, and to minimize the effect of process and supply variations and mismatches. In addition, we obtain a higher gain for the same voltage drop. Thus, the LNA gain is optimized and the noise figure (NF) is reduced. We derive equations for the gain, input matching and NF. The performance of this new topology is compared with that of a conventional LNA with resistors. Simulation results with a 130 nm CMOS technology show that we obtain a balun LNA with a peak gain of 20.2 dB (about 2 dB improvement), and a spot NF lower than 2.4 dB. The total power consumption is only 4.8 mW for a bandwidth higher than 6 GHz.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 3; 241-248
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Co-design of a low-power RF receiver and piezoelectric energy harvesting power supply for a Wireless Sensor Node
Autorzy:
Mancelos, N
Correia, J
Oliveira, J. P.
Oliveira, L. B.
Powiązania:
https://bibliotekanauki.pl/articles/398018.pdf
Data publikacji:
2014
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
CMOS RF analog front-end
low-voltage wideband balun LNA
passive mixer
piezoelectric energy harvesting
active full bridge rectifier
LDO regulator
układ analogowy CMOS
balun szerokopasmowy
mikser pasywny
energia piezoelektryczna
prostownik aktywny
prostownik mostkowy
regulator LDO
Opis:
A low-voltage RF CMOS receiver front-end and an energy harvesting power circuit for a piezoelectric source are presented as a co-designed solution for a Wireless Sensor Node. A MOSFET-only Wideband balun LNA with noise cancelling and a 0.6 V supply voltage is designed in conjunction with a passive mixer. The passive mixer operates in current mode, allowing a minimal introduction of voltage noise and a good linearity. The receiver front-end reaches a total voltage conversion gain of 31 dB, a 0.1-5.2 GHZ bandwidth, an IIP3 value of -1.35 dBm, and a noise figure inferior to 9 dB. The total power consumption is 1.95 mW. The energy harvesting power circuit consists of an active full bridge cross-coupled rectifier followed by a low-dropout (LDO) regulator, and it is able to guarantee a power output of 6 mW with a regulated output voltage of 0.6 V, for typical vibration patterns.
Źródło:
International Journal of Microelectronics and Computer Science; 2014, 5, 4; 136-143
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cascode amplifiers with low-gain variability and gain enhancement using a body-biasing technique
Autorzy:
Pereira, N
Oliveira, L. B.
Goes, J.
Oliveira, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/398063.pdf
Data publikacji:
2013
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
amplifier
body-biasing
cascode
CMOS analog circuits
PVT compensation
wzmacniacz
kaskoda
układy analogowe CMOS
kompensacja PVT
Opis:
This paper presents a simple circuit technique to reduce gain variability with PVT variations in cascode amplifiers using a body-biasing scheme, while enhancing the overall gain of the amplifier. Simulation results of a standard telescopic-cascode amplifier, in two different nanoscale CMOS technologies (130 nm and 65 nm) show that the proposed compensated circuit amplifier exhibits a (DC) gain variability smaller (below ± 0.5 dB) than the original (uncompensated) circuit, while reaching a gain enhancement of about 3 dB. The required auxiliary biasing circuit dissipates around 5% of the main amplifier circuit.
Źródło:
International Journal of Microelectronics and Computer Science; 2013, 4, 3; 98-102
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lower Toarcian organic-rich sediments from the Tuscan Succession (Northern Apennines, Italy): preliminary results
Autorzy:
Perilli, N.
Rodrigues, R.
Veiga de Oliveira, L.
Catanzariti, R.
Powiązania:
https://bibliotekanauki.pl/articles/2061357.pdf
Data publikacji:
2009
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
black shales
Early Toarcian
calcareous nannofossils
Tuscan Nappe
Northern Apennines
Italy
Opis:
For the first time is here documented the presence of Lower Toarcian black shales in the lower portion of the Calcari e marne a Posidonia (Posidonia Marls auctt.) belonging to the Tuscan Nappe. It consists of alternations of 30 cm to 5 m thick black laminated marlstone and marly claystone, with TOC values ranging from 0.43% to 2.49%. Based on calcareous nannofossils, the basal portion of the Calcari e marne a Posidonia spans the Lotharingius hauffii to Carinolithus superbus zones, and the organic-rich interval lies within the Carinolithus superbus Zone.
Źródło:
Volumina Jurassica; 2009, 7, 1; 55-65
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and design of CMOS coupled multivibrators
Autorzy:
Casaleiro, J.
Lopes, H. F.
Oliveira, L. B.
Filanovsky, I.
Powiązania:
https://bibliotekanauki.pl/articles/397859.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
multiwibrator
CMOS oscillator
multivibrator
quadrature outputs
van der Pol oscillator
WMTS appications
Opis:
In this paper a wideband MOS quadrature oscillator constituted by two multivibrators is presented. Two different forms of coupling, named here as soft and hard, are investigated. Simulations are performed in a 0.13 žm CMOS technology to obtain the tuning range, the synchronization transients, and the influence of mismatches in timing capacitors and charging currents on synchronization. It is found that hard coupling reduces the quadrature error (about 1°, with 5% mismatches in timing capacitors and charging currents) and results in a low phase-noise (about 2 dB improvement) with respect to soft coupling. Either a single multivibrator or coupled multivibrators can be locked to an external synchronizing harmonic frequency, and the locking range is investigated by simulations. The simulations are done for oscillators covering the WTMS frequency bands.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 3; 249-256
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Simplified Design Methodology for MOSFET-Only Wideband Mixer
Autorzy:
Ortigueira, E.
Bastos, I.
Oliveira, L. B.
Oliveira, J. P.
Goes, J.
Powiązania:
https://bibliotekanauki.pl/articles/227194.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CMOS mixers
MOSFET-only circuits
Gilbert cell
active mixers
wideband mixers
Opis:
In this paper we present a MOSFET-only implementation of a wideband Gilbert Cell. The circuit uses a commongate topology for a wideband input match, capable to cover the Wireless Medical Telemetry Service (WMTS) frequency bands of 600 MHz and 1.4 GHz. In this circuit the load resistors are replaced by transistors in triode region, to reduce area and cost, and minimize the effects of process and supply variations and mismatches. In addition, we obtain a higher gain for the same DC voltage drop, with a reduced impact on the noise figure (NF). The performance of this topology is compared with that of a conventional mixer with load resistors. Simulation results show that a peak gain of 20.6 dB (about 6 dB improvement) and a NF about of 11 dB for the 600 MHz band. The total power consumption is 3.6 mW from a 1.2 V supply.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 4; 503-509
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultra-low-voltage LNA with high gain and low noise figure
Autorzy:
Bastos, I.
Oliveira, L. B.
Oliveira, J. P.
Goes, J.
Silva, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/397785.pdf
Data publikacji:
2013
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
LNA
CMOS
noise cancellation
redukcja szumów
Opis:
We present a balun LNA with noise and distortion cancellation using double feedforward. A common-gate and a common-source stage are combined, and their resistive loads are replaced by transistors biased close to saturation to allows low supply voltage, without gain degradation. The proposed feedforward boosts the LNA gain and reduces the noise figure (NF). Simulation results with a 130 nm CMOS technology show that the gain is up to 24 dB and the NF is below 3.2 dB. The total power dissipation is 2.25 mW, leading to an FoM of 6.4 mW-1 with 0.6 V supply.
Źródło:
International Journal of Microelectronics and Computer Science; 2013, 4, 3; 124-128
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal assisted switching magnetic tunnel junctions as FPGA memory elements
Autorzy:
Silva, V.
Fernandes, J. R.
Oliveira, L. B.
Neto, H. C.
Ferreira, R.
Freitas, S.
Freitas, P. P.
Powiązania:
https://bibliotekanauki.pl/articles/397855.pdf
Data publikacji:
2010
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
MRAM (oporność magnetyczna pamięci o dostępie swobodnym)
MTJ (magnetyczny tunel połączeń)
pisanie projektów (programów)
FIMS (pole indukowane magnetycznym przełącznikiem)
MRAM (magnetoresistive random access memory)
MTJ (magnetic tunnel junction)
writing schemes
FIMS (field induced magnetic switching)
TAS (thermal assisted switching)
STT
Opis:
This paper presents our research and development work on new circuits and topologies based on Magnetic RAM for use as configuration memory elements of reconfigurable arrays. MRAM provides non volatility with cell areas and with access speeds comparable to those of SRAM and with lower process complexity than FLASH memories. The new memory cells take advantage of the Thermal Assisted Switching (TAS) writing technique to solve the drawbacks of the more common Field Induced Magnetic Switching writing technique. The CMOS circuit structures to implement the main components for reading and writing the MTJ cells have been developed, characterized and evaluated. A scaled down prototype of a coarse grain reconfigurable array that employs the TAS-MRAM elements as configuration memory has been designed and electrically simulated pre- and post- layout. The results obtained for all the circuit elements, namely the storage cells and the current generators, indicate that the new configuration memory cells can provide a very promising technological solution for run-time reconfigurable hardware devices. The prototype has been manufactured using a standard process 0.35μm 4-Metal CMOS process technology and should be under test in the foreseeable future.
Źródło:
International Journal of Microelectronics and Computer Science; 2010, 1, 1; 31-36
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hypertonic saline solution (NaCl 7.2%) enhances renal excretion of acids in cattle with acute ruminal lactic acidosis
Autorzy:
Rodrigues, F.A.M.L.
Minervino, A.H.H.
Barrêto Júnior, R.A.
Reis, L.F.
Ferreira, R.N.F.
Mori, C.S.
Oliveira, F.L.C.
Sousa, R.S.
Powiązania:
https://bibliotekanauki.pl/articles/2087583.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steers
ruminal lactic acidosis
hypertonic saline solution
Źródło:
Polish Journal of Veterinary Sciences; 2019, 1; 37-42
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tanystropheid archosauromorphs in the Lower Triassic of Gondwana
Autorzy:
De Oliveira, T.M.
Oliveira, D.
Schultz, C.L.
Kerber, L.
Pinheiro, F.L.
Powiązania:
https://bibliotekanauki.pl/articles/23531.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Tanystropheidae is a clade of early archosauromorphs with a reported distribution ranging from the Early to the Late Triassic of Asia, Europe, and North America. Although some specimens with possible tanystropheid affinities from the Lower Triassic beds of Brazil have been previously attributed to “Protorosauria”, little is known about the tanystropheid record in Gondwana. Here, two new and one previously reported specimen from the Sanga do Cabral Formation (Induan–Olenekian) of Brazil are described and interpreted as ?Tanystropheidae. These records, together with other tetrapods previously reported for the Sanga do Cabral Formation, increase the knowledge of the biotic diversification during the beginning of the Triassic. This contribution reinforces that the archosauromorph diversification occurred shortly after the Permo-Triassic extinction, making the Sanga do Cabral Formation an important unit for the study of early Mesozoic faunas.
Źródło:
Acta Palaeontologica Polonica; 2018, 63, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Functional morphology and biomechanics of the cynodont Trucidocynodon riograndensis from the Triassic of Southern Brazil: Pectoral girdle and forelimb
Autorzy:
de Oliveira, T.V.
Schultz, C.L.
Powiązania:
https://bibliotekanauki.pl/articles/20204.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
functional morphology
biomechanics
cynodont
Trucidocynodon riograndensis
Cynodontia
Trucidocynodon
limb posture
Carnian
Triassic
Brazil
pectoral girdle
forelimb
Opis:
Non-mammalian cynodonts provide insights on several points about mammalian evolution, such as the postural change and locomotory advances within the group. Unfortunately, complete skeletons of Triassic cynodonts are rather uncommon and where more complete specimens are found they can offer a global vision on some traits not available from partial specimens. This is the case of the cynodont Trucidocynodon riograndensis, from the Triassic of Brazil, that has preserved its forelimbs providing some insights into locomotory properties. The movements between interclavicle and clavicle must have been limited, as such as those occurring between the latter and the scapulocoracoid although the long acromion process of this should have permitted a greater degree of freedom. Some of the more significant movements were those on the shoulder joint, in which the maximum adduction should have been ca. 35º relative to the parasagittal plane and the greater abduction ca. 55º. The maximum adduction occurred when the humerus was in the more retracted position during stride and the variation in the adduction/abduction should have been significant to the limb posture during its recovery stroke. The long olecranon and the distal overlapping between radius and ulna suggest the predominance of simple flexion/extension on the forearm without significant pronation/supination. The poorly preserved hand suggests that Trucidocynodon could have evolved a slight semidigitigrad condition in its forelimbs. All these features give to this cynodont an important role in the evolution of the mammalian locomotory properties indicating that some features, such as the possibility of greater humeral adduction, evolved early in cynodont lineage.
Źródło:
Acta Palaeontologica Polonica; 2016, 61, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monogenoidea parasites of Cichla monoculus and Cichla pinima (Osteichthyes: Cichlidae), sympatric fish in lower Tapajós River, Northern Brazil
Autorzy:
Oliveira, M.S.B.
Adriano, E.A.
Tavares-Dias, M.
Correa, L.L.
Powiązania:
https://bibliotekanauki.pl/articles/6677.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Parazytologiczne
Źródło:
Annals of Parasitology; 2019, 65, 4
0043-5163
Pojawia się w:
Annals of Parasitology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biofilm - formation by Staphylococcus aureus and Staphylococcus epidermidis isolates from subclinical mastitis in conditions mimicking the udder environment
Autorzy:
Seixas, R.
Varanda, D.
Bexiga, R.
Tavares, L.
Oliveira, M.
Powiązania:
https://bibliotekanauki.pl/articles/30529.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Staphylococcus is the genus most commonly isolated from bovine mastitis in many countries. It may express several virulence factors including biofilm formation, which may protect the bacterial community from antimicrobials’ action, preventing these compounds from reaching its interior, where they reach subinhibitory concentrations (subMIC). Most biofilm production assays are performed in static conditions, while studies regarding antimicrobial resistance usually do not resemble the udder environment because they are performed at high concentrations. In this study we evaluated the influence of dynamic conditions and media, including Mueller Hinton Broth (MHB) and UHT whole milk (WM), as well as the effect of subMIC concentrations of five different antimicrobial agents on biofilm formation by staphylococci isolated from subclinical mastitis. Results suggest that dynamic conditions and media may influence biofilm formation and revealed that milking simulation may significantly increase biofilm production. Sub- MIC concentrations decrease biofilm formation in MHB but increase in WM, suggesting a protective role of milk against antimicrobial compounds’ action. Therefore, in vitro conditions that simulate the udder environment and in vivo conditions should be included as one of the parameters in evaluation of biofilm producing strains, in order to provide more reliable results.
Źródło:
Polish Journal of Veterinary Sciences; 2015, 18, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł

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