23,214 research outputs found
Conformal mapping of ultrasonic crystals: confining ultrasound and cochlear-like wave guiding
Conformal mapping of a slab of a two-dimensional ultrasonic crystal generate
a closed geometrical arrangement of ultrasonic scatterers with appealing
acoustic properties. This acoustic shell is able to confine ultrasonic modes.
Some of these internal resonances can be induced from an external wave source.
The mapping of a linear defect produces a wave-guide that exhibits a
spatial-frequency selection analogous to that characteristic of a synthetic
"cochlea". Both, experimental and theoretical results are reported here.Comment: 4 pages, 4 figure
SACY - a Search for Associations Containing Young stars
The scientific goal of the SACY (Search for Associations Containing
Young-stars) was to identify possible associations of stars younger than the
Pleiades Association among optical counterparts of the ROSAT X-ray bright
sources. High-resolution spectra for possible optical counterparts later than
G0 belonging to HIPPARCOS and/or TYCHO-2 catalogs were obtained in order to
assess both the youth and the spatial motion of each target. More than 1000
ROSAT sources were observed, covering a large area in the Southern Hemisphere.
The newly identified young stars present a patchy distribution in UVW and XYZ,
revealing the existence of huge nearby young associations. Here we present the
associations identified in this survey.Comment: 8 pages, 2 figures, to appear in the Proceedings of Open Issues in
Local Formation and Early Stellar Evolution, Ouro Preto, Brazi
Estratégias de manejo visando a melhoria da pecuária de leite familiar do Norte de Minas e do Vale do Jequitinhonha.
bitstream/item/132475/1/Livro-Estrategias-de-manejo-visando-a-melhoria-da-pecuaria.pd
Efeito de níveis de uréia no concentrado sobre a digestibilidade e balanço de nitrogênio em ovinos.
O estudo foi realizado com o objetivo de verificar o efeito de níveis crescentes de uréia associada ao milho sobre a digestibilidade e balanço de nitrogênio. Foram utilizados 16 carneiros distribuídos em quatro blocos de acordo com o peso vivo
Coherent delocalization: Views of entanglement in different scenarios
The concept of entanglement was originally introduced to explain correlations
existing between two spatially separated systems, that cannot be described
using classical ideas. Interestingly, in recent years, it has been shown that
similar correlations can be observed when considering different degrees of
freedom of a single system, even a classical one. Surprisingly, it has also
been suggested that entanglement might be playing a relevant role in certain
biological processes, such as the functioning of pigment-proteins that
constitute light-harvesting complexes of photosynthetic bacteria. The aim of
this work is to show that the presence of entanglement in all of these
different scenarios should not be unexpected, once it is realized that the very
same mathematical structure can describe all of them. We show this by
considering three different, realistic cases in which the only condition for
entanglement to exist is that a single excitation is coherently delocalized
between the different subsystems that compose the system of interest
Efeito da suplementação com nitrogênio e enxofre no consumo e ganho de peso por novilhas alimentadas com cana-de-açúcar.
Verificar o efeito da suplementacao, de uma dieta a base de cana de acucar para novilhas, com nitrogenio nao protetico e enxofre, sobre consumo, ganho de peso e conversao alimentar
- …