1,228 research outputs found
Hybrid confinement of optical and mechanical modes in a bullseye optomechanical resonator
Optomechanical cavities have proven to be an exceptional tool to explore
fundamental and technological aspects of the interaction between mechanical and
optical waves. Such interactions strongly benefit from cavities with large
optomechanical coupling, high mechanical and optical quality factors, and
mechanical frequencies larger than the optical mode linewidth, the so called
resolved sideband limit. Here we demonstrate a novel optomechanical cavity
based on a disk with a radial mechanical bandgap. This design confines light
and mechanical waves through distinct physical mechanisms which allows for
independent control of the mechanical and optical properties. Our device design
is not limited by unique material properties and could be easily adapted to
allow large optomechanical coupling and high mechanical quality factors with
other promising materials. Finally, our demonstration is based on devices
fabricated on a commercial silicon photonics facility, demonstrating that our
approach can be easily scalable.Comment: 16 pages, 11 figure
Equation of state of charged colloidal suspensions and its dependence on the thermodynamic route
The thermodynamic properties of highly charged colloidal suspensions in
contact with a salt reservoir are investigated in the framework of the
Renormalized Jellium Model (RJM). It is found that the equation of state is
very sensitive to the particular thermodynamic route used to obtain it.
Specifically, the osmotic pressure calculated within the RJM using the contact
value theorem can be very different from the pressure calculated using the
Kirkwood-Buff fluctuation relations. On the other hand, Monte Carlo (MC)
simulations show that both the effective pair potentials and the correlation
functions are accurately predicted by the RJM. It is suggested that the lack of
self-consistency in the thermodynamics of the RJM is a result of neglected
electrostatic correlations between the counterions and coions
A combined approach for comparative exoproteome analysis of Corynebacterium pseudotuberculosis
Background: Bacterial exported proteins represent key components of the host-pathogen interplay. Hence, we
sought to implement a combined approach for characterizing the entire exoproteome of the pathogenic
bacterium Corynebacterium pseudotuberculosis, the etiological agent of caseous lymphadenitis (CLA) in sheep and
goats.
Results: An optimized protocol of three-phase partitioning (TPP) was used to obtain the C. pseudotuberculosis
exoproteins, and a newly introduced method of data-independent MS acquisition (LC-MSE) was employed for
protein identification and label-free quantification. Additionally, the recently developed tool SurfG+ was used for in
silico prediction of sub-cellular localization of the identified proteins. In total, 93 different extracellular proteins of
C. pseudotuberculosis were identified with high confidence by this strategy; 44 proteins were commonly identified
in two different strains, isolated from distinct hosts, then composing a core C. pseudotuberculosis exoproteome.
Analysis with the SurfG+ tool showed that more than 75% (70/93) of the identified proteins could be predicted as
containing signals for active exportation. Moreover, evidence could be found for probable non-classical export of
most of the remaining proteins.
Conclusions: Comparative analyses of the exoproteomes of two C. pseudotuberculosis strains, in addition to
comparison with other experimentally determined corynebacterial exoproteomes, were helpful to gain novel
insights into the contribution of the exported proteins in the virulence of this bacterium. The results presented
here compose the most comprehensive coverage of the exoproteome of a corynebacterial species so far
Third-harmonic generation in silica wedge resonators
Whispering-gallery-mode microcavities are known to have high optical quality
factor, making them suitable for nonlinear optical interactions. Here,
third-harmonic generation is observed using a relatively small radius wedge
silicon oxide optical microcavity. The small radii wedge microdisks can be
dispersion-tailored to obtain either normal or anomalous group velocity
dispersion. In our case, we operate in the normal dispersion regime preventing
frequency comb generation by suppressing infrared cascading four-wave mixing.
This allows for a clean third harmonic generation at phase-matched visible
optical modes. Tunability of the third-harmonic emission is obtained due to a
combination of the thermo-optical and Kerr effects. An additional thermal
control of the phase matching condition allows for optimizing third-harmonic
generation, and agreement between this process and couple-mode theory is
demonstrated.Comment: 6 pages, 6 figure
Evolution of Black-Box Models Based on Volterra Series
This paper presents a historical review of the many behavioral models actually used to model radio frequency power amplifiers and a new classification of these behavioral models. It also discusses the evolution of these models, from a single polynomial to multirate Volterra models, presenting equations and estimation methods. New trends in RF power amplifier behavioral modeling are suggested
Intake Rate and Nutritive Value of Elephant Grass cv. Napier Subjected to Strategies of Rotational Stocking Management
Several research papers on forage tropical grass species have demonstrated that grazing management interferes with sward structure that, in turn, alters patterns of ingestive and foraging behaviour of the grazing animals. For that reason it has been used as explicative variable for adjustments in intake characteristics like bite mass, bite rate, intake rate and nutritive value of the consumed herbage (Fonseca et al. 2012). Tall tufted growing plants like elephant grass (Pennisetum purpureum Schum.) cv. Napier show a continuous pattern of growth characterised by stem elongation during their vegetative state (Da Silva and Carvalho 2005), causing swards to become too tall and out of reach for grazing animals, generating serious difficulties in executing efficient grazing management, particularly when long regrowth periods are used. In that context, the increase in defoliation frequency has positive effects on herbage intake and nutritive value (Palhano et al. 2007), since it favours leaf elongation relative to stem elongation and senescent material accumulation throughout successive grazing cycles. Against that background, the objective of this experiment was to evaluate the components of the short term herbage intake (intake rate, bite mass and bite rate) and the nutritive value of the consumed herbage from elephant grass cv. Napier subjected to strategies of rotational stocking management defined in terms of pre- and post-grazing management targets
Efficient anchor loss suppression in coupled near-field optomechanical resonators
FUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICO - CNPQElastic dissipation through radiation towards the substrate is a major loss channel in micro-and nanomechanical resonators. Engineering the coupling of these resonators with optical cavities further complicates and constrains the design of low-loss optomechanical devices. In this work we rely on the coherent cancellation of mechanical radiation to demonstrate material and surface absorption limited silicon near-field optomechanical resonators oscillating at tens of MHz. The effectiveness of our dissipation suppression scheme is investigated at room and cryogenic temperatures. While at room temperature we can reach a maximum quality factor of 7.61k (fQ-product of the order of 10(11) Hz), at 22 K the quality factor increases to 37k, resulting in a fQ-product of 2 x 10(12) Hz.25253134731361FUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICO - CNPQFUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICO - CNPQ2008/57857-22012/17610-32012/17765-7153044/2013-
Moringa oleifera: Resource management and multiuse life tree
Moringa oleifera Lamarck (Moringaceae family) is a plant native from the Western and sub-Himalayan parts of Northwest India, Pakistan and Afghanistan. This species is widely cultivated across Africa, South-East Asia, Arabia, South America and Caribbean Islands. M. oleifera culture is also being distributed in the Semi-Arid Northeast of Brazil. It is a multiuse life tree with great environmental economic importance in industrial and medical areas. This review reports different purposes of M. oleifera including sustaining environmental resources, soil protection and shelter for animals. This plant requires not much care and distinct parts have bioactive compounds. Moringa tissues used in human and animal diets, also withdraw pollutants from water. The seeds with coagulant properties used in water treatment for human consumption, remove waste products like surfactants, heavy metals and pesticides. The oil extracted from seeds is used in cosmetic production and as biodiesel. M. oleifera tissues also contain proteins with different biological activities, including lectins, chitin-binding proteins, trypsin inhibitors, and proteases. The lectins are reported to act as insecticidal agents against Aedes aegypti (vector of dengue, chikungunya and yellow fevers) and Anagasta kuehniella (pest of stored products) and also showed water coagulant, antibacterial and blood anticoagulant activities. The presence of trypsin inhibitors has been reported in M. oleifera leaves and flowers. The inhibitor from flowers is toxic to larvae of A. aegypti. The flowers also contain caseinolytic proteases that are able to promote clotting of milk. In this sense, M. oleifera is a promising tree from a biotechnological point of view, since it has shown a great variety of uses and it is a source of several compounds with a broad range of biological activities.Conselho Nacional de Desenvolvimento
CientĂfico e TecnolĂłgico for fellowship (LCBBC)
and to the Foundation for Science and
Technology, POPH/FSE (AFSS
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