22,874 research outputs found
The needs of people with dementia living at home from user, caregiver and professional perspectives: a cross-sectional survey
Few reports have been published about differences in perspectives on perceived needs among community-residing people with dementia, their family caregivers, and professionals. The aim of this study was to compare these perspectives
On Galois-Division Multiple Access Systems: Figures of Merit and Performance Evaluation
A new approach to multiple access based on finite field transforms is
investigated. These schemes, termed Galois-Division Multiple Access (GDMA),
offer compact bandwidth requirements. A new digital transform, the Finite Field
Hartley Transform (FFHT) requires to deal with fields of characteristic p, p
\neq 2. A binary-to-p-ary (p \neq 2) mapping based on the opportunistic
secondary channel is introduced. This allows the use of GDMA in conjunction
with available digital systems. The performance of GDMA is also evaluated.Comment: 6 pages, 4 figures. In: XIX Simposio Brasileiro de Telecomunicacoes,
2001, Fortaleza, CE, Brazi
Spectroscopic confirmation of the planetary nebula nature of PM1-242, PM1-318 and PM1-333 and morphological analysis of the nebulae
We present intermediate resolution long-slit spectra and narrow-band Halpha,
[NII] and [OIII] images of PM1-242, PM318 and PM1-333, three IRAS sources
classified as possible planetary nebulae. The spectra show that the three
objects are true planetary nebulae and allow us to study their physical
properties; the images provide a detailed view of their morphology. PM1-242 is
a medium-to-high-excitation (e.g., HeII4686/Hbeta ~0.4; [NII]6584/Halpha ~0.3)
planetary nebula with an elliptical shape containing [NII] enhanced
point-symmetric arcs. An electron temperature [Te([SIII])] of ~10250 K and an
electron density [Ne([SII])] of ~2300 cm-3 are derived for PM1-242. Abundance
calculations suggest a large helium abundance (He/H ~0.29) in PM1-242. PM1-318
is a high-excitation (HeII4686/Hbeta ~1) planetary nebula with a ring-like
inner shell containing two enhanced opposite regions, surrounded by a fainter
round attached shell brighter in the light of [OIII]. PM1-333 is an extended
planetary nebula with a high-excitation (HeII4686/Hbeta up to ~0.9) patchy
circular main body containing two low-excitation knotty arcs. A low Ne([SII])
of ~450 cm-3 and Te([OIII]) of ~15000 K are derived for this nebula. Abundance
calculations suggest that PM1-333 is a type I planetary nebula. The lack of a
sharp shell morphology, low electron density, and high-excitation strongly
suggest that PM1-333 is an evolved planetary nebula. PM1-333 also shows two
low-ionization polar structures whose morphology and emission properties are
reminiscent of collimated outflows. We compare PM1-333 with other evolved
planetary nebulae with collimated outflows and find that outflows among evolved
planetary nebulae exhibit a large variety of properties, in accordance with
these observed in younger planetary nebula.Comment: Accepted in The Astronomical Journal, 23 pages, 6 figure
Chiral spin-orbital liquids with nodal lines
Strongly correlated materials with strong spin-orbit coupling hold promise
for realizing topological phases with fractionalized excitations. Here we
propose a chiral spin-orbital liquid as a stable phase of a realistic model for
heavy-element double perovskites. This spin liquid state has Majorana fermion
excitations with a gapless spectrum characterized by nodal lines along the
edges of the Brillouin zone. We show that the nodal lines are topological
defects of a non-Abelian Berry connection and that the system exhibits
dispersing surface states. We discuss some experimental signatures of this
state and compare them with properties of the spin liquid candidate Ba_2YMoO_6.Comment: 5 pages + supplementary materia
Observational Constraints on Visser's Cosmological Model
Theories of gravity for which gravitons can be treated as massive particles
have presently been studied as realistic modifications of General Relativity,
and can be tested with cosmological observations. In this work, we study the
ability of a recently proposed theory with massive gravitons, the so-called
Visser theory, to explain the measurements of luminosity distance from the
Union2 compilation, the most recent Type-Ia Supernovae (SNe Ia) dataset,
adopting the current ratio of the total density of non-relativistic matter to
the critical density () as a free parameter. We also combine the SNe
Ia data with constraints from Baryon Acoustic Oscillations (BAO) and CMB
measurements. We find that, for the allowed interval of values for ,
a model based on Visser's theory can produce an accelerated expansion period
without any dark energy component, but the combined analysis (SNe Ia + BAO +
CMB) shows that the model is disfavored when compared with CDM model.Comment: 6 pages, 4 figure
3d Modularity
We find and propose an explanation for a large variety of modularity-related
symmetries in problems of 3-manifold topology and physics of 3d
theories where such structures a priori are not manifest. These modular
structures include: mock modular forms, Weil
representations, quantum modular forms, non-semisimple modular tensor
categories, and chiral algebras of logarithmic CFTs.Comment: 119 pages, 10 figures and 20 table
Fixação de nitrogênio pela soja em sistemas de cultivo contÃnuo e rotacionado com pecuária nos Cerrados.
Quantificou-se a contribuição da fixação biológica de N2 (FBN) na cultura da soja em um Latossolo Vermelho-Escuro, utilizando-se a técnica da abundância natural do isótopo 15N. Foram estudados cinco tratamentos: 1) soja de primeiro ano em solo cultivado por quatro anos com Brachiaria decumbens, sob pastejo, e preparado mecanicamente (arado, grade pesada e niveladora); 2) mesmas condições anteriores, mas com plantio direto da soja; 3) soja em cultivo contÃnuo por cinco anos, como cultura de verão, sem plantio de milheto no outono/ inverno, e solo preparado de forma convencional (arado, grade pesada e niveladora); 4) soja com cultivo contÃnuo por cinco anos, com cultivo de outono/inverno de milheto (Pennisetum atropurpureum) e preparo de solo conservacionista (arado de disco, aiveca e subsolador); 5) mesmas condições anteriores, mas com plantio direto. Amostras de plantas foram coletadas no estádio vegetativo, enchimento de grãos, na maturação, e na colheita final de grãos. Em cada coleta analisaram-se as produções de matéria seca (MS) e teores de N e 15N. As produções de MS e N total acumulado foram semelhantes no estádio vegetativo, mas as plantas no plantio direto mostraram taxas de FBN acima de 50%, enquanto que as de plantio convencional estavam abaixo de 40%. No enchimento de grãos, as produções de MS, N total e as taxas de FBN(entre 60% e 68%) foram semelhantes em todos os sistemas de preparo do solo. Na maturação dos grãos, o preparo de solo convencional resultou numa maior produção de MS do que no plantio direto. Os grãos apresentaram a maior parte do N fixado (66% a 82%), ficando entre 51% e 68% para a parte aérea e entre 15% e 32% para as raÃzes. No balanço do N total obtido por FBN e o que foi alocado aos grãos, obtiveram-se valores indicativos de que a maior parte do N fixado seria retirada do sistema na colheita de grãos, o que foi confirmado na colheita final. A soja de plantio direto mostrou um balanço ligeiramente mais positivo do que a soja de plantio convencional. Como a soja é pouco dependente do N do solo, usando eficientemente o N de fixação, este seria poupado como resÃduo para uso de culturas subseqüentes, o que explicaria o efeito benéfico imediato observado na prática em sistemas produtivos de rotação de cultura entre soja e cereais ou pastagem. No entanto, os resultados obtidos indicam que a soja, que tem um Ãndice de colheita alto (proporção do N total nos grãos em relação ao N total da planta), não contribui significativamente para aumento dos teores de N total do solo capazes de beneficiar por longo tempo as culturas em sucessão.bitstream/CNPGC/10292/1/BP14.pd
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