296 research outputs found
Monolithically integrated DBR waveguidelaser and intensity modulator in erbiumdoped LiNbO3
For the first time, a DBR laser has been integrated with a Mach
Zehnder intensity modulator in Er diffusion doped, Z cut
LiNbO,, with Ti indiffused waveguides and dry etched Bragg
gratings. The monolithically integrated device has a threshold of
54.8mW incident pump power (hp = 1480nm) and emits, in a
single longitudinal mode, up to 0.65 mW CW output power at hs
= 1561nm. The Mach-Zehnder type intensity modulator has an
optical bandwidth > 3GHz
Ferramentas computacionais de apoio às boas práticas de manejo de tilápia.
A piscicultura brasileira cresce cerca de 30% ao ano, por tratar-se de fonte de proteína de alta qualidade e pela lucratividade. De origem africana, a tilapicultura está presente hoje em grande parte do território nacional, mas ainda sofrendo as pressões para a maior qualidade do produto e adoção de práticas menos impactantes ao ambiente. Entre alguns desses impactos citam-se as poluição e interferências em níveis de biodiversidade e de qualidade da água. Assim, o produtor carece de informação e ferramentas que favoreçam a rápida transferência de práticas já identificadas pela pesquisa, que aumentem seu conhecimento e agilidade na incorporação destas às atividades da propriedade. O projeto "Manejo e Gestão Ambiental da Aqüicultura" da Embrapa Meio Ambiente, componente do projeto em rede Aquabrasil, vem identificando Boas Práticas de Manejo (BPM) de tilápia passíveis de uso imediato pelo produtor a partir de sua rápida observação da propriedade. Nele, o sistema informatizado Aquisys está em desenvolvimento para vialibizar o acesso dinâmico, via web, às avaliações e indicadores de produção, manejo e qualidade de água em atenção às BPM. Este trabalho apresenta duas de suas ferramentas computacionais desenvolvidas para tilápia: a) um sistema especialista de rápida avaliação de BPM na propriedade (em linguagem CLIPS); e b) um programa para determinar a %ração e %proteína bruta a ser oferecida, considerando os pesos dos peixes e temperatura local (em linguagens PHP e HTML)
Direct measurement of local constitutive relations, at the micrometre scale, in bulk metallic alloys
Multiscale models involving crystal plasticity are essential to predict the elastoplastic behavior of structural materials with respect to their microstructure. However, those models are often limited by a poor knowledge of the local constitutive behavior. This article reports a method to measure the mechanical behavior directly, at the micrometre scale, in bulk crystalline materials. Local strain and stress states were evaluated at the surface of a bent stainless steel crystal by combining total strain measurements – performed with the digital image correlation technique on optical images – with elastic strain measurements obtained by Laue microdiffraction. A local constitutive relation was measured, in an efficient nondestructive way, without the need for full-field simulations. The method was validated by a comparison between the measured local behavior and the macroscopic behavior of the single crystal
Relationship Between Biogenic Amines and Free Amino Acid Contents of Winesand Musts from Alentejo (Portugal)
The concentration of biogenic amines and free amino acids was studied in 102
Portuguese wines and 18 musts from Alentejo demarcated (D.O.C.) regions. Most wines
were commercial, except for 38 monovarietals obtained by micro vinification. Musts
from the varieties used to produce the latter wines were also studied. Both biogenic
amines and free amino acids were analyzed by HPLC using fluorescence detection for
their o-phthalaldehyde/fluorenylmethyl chloroformate (OPA/FMOC) derivatives. The
most significant amines (average 10.8 mg/L for histamine+tyramine in red, and 7.4
mg/L for white wines) were found to be present at low levels and, although no important
relationship between each individual biogenic amine could be obtained, the total amine
content depends significantly on the assimilable amino acid content in wine
White Paper and Roadmap for Quantum Gravity Phenomenology in the Multi-Messenger Era
The unification of quantum mechanics and general relativity has long been elusive. Only recently have empirical predictions of various possible theories of quantum gravity been put to test. The dawn of multi-messenger high-energy astrophysics has been tremendously beneficial, as it allows us to study particles with much higher energies and travelling much longer distances than possible in terrestrial experiments, but more progress is needed on several fronts. A thorough appraisal of current strategies and experimental frameworks, regarding quantum gravity phenomenology, is provided here. Our aim is twofold: a description of tentative multimessenger explorations, plus a focus on future detection experiments. As the outlook of the network of researchers that formed through the COST Action CA18108 "Quantum gravity phenomenology in the multi-messenger approach (QG-MM)", in this work we give an overview of the desiderata that future theoretical frameworks, observational facilities, and data-sharing policies should satisfy in order to advance the cause of quantum gravity phenomenology
White Paper and Roadmap for Quantum Gravity Phenomenology in the Multi-Messenger Era
The unification of quantum mechanics and general relativity has long been
elusive. Only recently have empirical predictions of various possible theories
of quantum gravity been put to test. The dawn of multi-messenger high-energy
astrophysics has been tremendously beneficial, as it allows us to study
particles with much higher energies and travelling much longer distances than
possible in terrestrial experiments, but more progress is needed on several
fronts.
A thorough appraisal of current strategies and experimental frameworks,
regarding quantum gravity phenomenology, is provided here. Our aim is twofold:
a description of tentative multimessenger explorations, plus a focus on future
detection experiments.
As the outlook of the network of researchers that formed through the COST
Action CA18108 "Quantum gravity phenomenology in the multi-messenger approach
(QG-MM)", in this work we give an overview of the desiderata that future
theoretical frameworks, observational facilities, and data-sharing policies
should satisfy in order to advance the cause of quantum gravity phenomenology.Comment: Submitted to CQG for the Focus Issue on "Quantum Gravity
Phenomenology in the Multi-Messenger Era: Challenges and Perspectives".
Please contact us to express interesst of endorsement of this white pape
Cosmology with the Laser Interferometer Space Antenna
The Laser Interferometer Space Antenna (LISA) has two scientific objectives of cosmological focus: to probe the expansion rate of the universe, and to understand stochastic gravitational-wave backgrounds and their implications for early universe and particle physics, from the MeV to the Planck scale. However, the range of potential cosmological applications of gravitational wave observations extends well beyond these two objectives. This publication presents a summary of the state of the art in LISA cosmology, theory and methods, and identifies new opportunities to use gravitational wave observations by LISA to probe the universe
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