746 research outputs found
Signal Transmission Across Tile Assemblies: 3D Static Tiles Simulate Active Self-Assembly by 2D Signal-Passing Tiles
The 2-Handed Assembly Model (2HAM) is a tile-based self-assembly model in
which, typically beginning from single tiles, arbitrarily large aggregations of
static tiles combine in pairs to form structures. The Signal-passing Tile
Assembly Model (STAM) is an extension of the 2HAM in which the tiles are
dynamically changing components which are able to alter their binding domains
as they bind together. For our first result, we demonstrate useful techniques
and transformations for converting an arbitrarily complex STAM tile set
into an STAM tile set where every tile has a constant, low amount of
complexity, in terms of the number and types of ``signals'' they can send, with
a trade off in scale factor.
Using these simplifications, we prove that for each temperature
there exists a 3D tile set in the 2HAM which is intrinsically universal for the
class of all 2D STAM systems at temperature (where the STAM does
not make use of the STAM's power of glue deactivation and assembly breaking, as
the tile components of the 2HAM are static and unable to change or break
bonds). This means that there is a single tile set in the 3D 2HAM which
can, for an arbitrarily complex STAM system , be configured with a
single input configuration which causes to exactly simulate at a scale
factor dependent upon . Furthermore, this simulation uses only two planes of
the third dimension. This implies that there exists a 3D tile set at
temperature in the 2HAM which is intrinsically universal for the class of
all 2D STAM systems at temperature . Moreover, we show that for each
temperature there exists an STAM tile set which is intrinsically
universal for the class of all 2D STAM systems at temperature ,
including the case where .Comment: A condensed version of this paper will appear in a special issue of
Natural Computing for papers from DNA 19. This full version contains proofs
not seen in the published versio
Basic parameters of three star clusters in the Small Magellanic Cloud: Kron 11, Kron 63 and NGC 121
We present observations for three star clusters, Kron 11, Kron 63 and NGC 121, in the Small Magellanic Cloud. We have studied their structure and derived their fundamental parameters by means of their luminosity functions, their colour magnitude diagrams and the Padova suite of isochrones. NGC 121 is a well-studied object, for which we confirm previous evidence about its old age and low-metal content, and have found that it is an undergoing mass segregation. Kron 11 and Kron 63 are poorly populated clusters which had never been studied so far. Kron 11 is several gigayears younger than NGC 121, while Kron 63 is basically a very young star aggregate. Both clusters are immersed in dense stellar fields which share the same population properties, suggesting that in their cases, cluster ages are consistent with typical ages of field stars.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica
Basic parameters of three star clusters in the Small Magellanic Cloud: Kron 11, Kron 63 and NGC 121
We present observations for three star clusters, Kron 11, Kron 63 and NGC 121, in the Small Magellanic Cloud. We have studied their structure and derived their fundamental parameters by means of their luminosity functions, their colour magnitude diagrams and the Padova suite of isochrones. NGC 121 is a well-studied object, for which we confirm previous evidence about its old age and low-metal content, and have found that it is an undergoing mass segregation. Kron 11 and Kron 63 are poorly populated clusters which had never been studied so far. Kron 11 is several gigayears younger than NGC 121, while Kron 63 is basically a very young star aggregate. Both clusters are immersed in dense stellar fields which share the same population properties, suggesting that in their cases, cluster ages are consistent with typical ages of field stars.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica
Basic parameters of three star clusters in the Small Magellanic Cloud: Kron 11, Kron 63 and NGC 121
We present observations for three star clusters, Kron 11, Kron 63 and NGC 121, in the Small Magellanic Cloud. We have studied their structure and derived their fundamental parameters by means of their luminosity functions, their colour magnitude diagrams and the Padova suite of isochrones. NGC 121 is a well-studied object, for which we confirm previous evidence about its old age and low-metal content, and have found that it is an undergoing mass segregation. Kron 11 and Kron 63 are poorly populated clusters which had never been studied so far. Kron 11 is several gigayears younger than NGC 121, while Kron 63 is basically a very young star aggregate. Both clusters are immersed in dense stellar fields which share the same population properties, suggesting that in their cases, cluster ages are consistent with typical ages of field stars.Instituto de Astrofísica de La PlataFacultad de Ciencias Astronómicas y Geofísica
A depth-averaged model for non-isothermal thin-film rimming flow
A model for non-isothermal shear-driven thin-film flow on the inside surface of a stationary circular cylinder is presented. Motivated by an application to film flow in an aero-engine bearing chamber the model extends lubrication theory analysis of thin films to retain the important effects of inertia and heat convection.The accuracy of the depth-averaged temperature model is tested and comparisons illustrate the model is accurate for both conduction- and convection-dominant flows although local inaccuracies are introduced in regions exhibiting sharp changes in boundary temperature when convective effects are strong.Three rimming-flow configurations are considered: uni-directional flow with slowly-varying film height, a solution containing a steep front termed a shock, and a pooling solution where fluid accumulates in a recirculation at the base of the cylinder. The temperature field in the latter two which include recirculation features are greatly influenced by the strength of convection in the film
Agroclimatic zoning of the state of Minas Gerais for the production of high quality soybean seeds
APICULTURA SUSTENTÁVEL: PRODUÇÃO E COMERCIALIZAÇÃO DE MEL NO MEIO OESTE CATARINENSE
O presente trabalho tem como objetivo fomentar a produção de mel em larga escala, utilizando-se da apicultura de forma sustentável. A organização dos atores locais em Arranjos Produtivos será o principal mecanismo estratégico para gerar capital social e fomentar o projeto. A produção e a comercialização de mel no meio oeste catarinense será realizado através da criação de uma associação entre os moradores residentes no interior dos municípios integrantes da AMMOC (Associação dos Municípios do Meio Oeste Catarinense), e em pareceria com entidades necessárias na execução, como o Serviço Brasileiro de Apoio às Micro e Pequenas Empresas (SEBRAE), Associações de Apicultores e Meliponicultores de Santa Catarina (FAASC), Associação Brasileira dos Exportadores de Mel (ABEMEL), Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina (EPAGRI). A apicultura é uma atividade econômica de baixo impacto ambiental, que possibilita a utilização dos recursos naturais, de maneira que contribui com a manutenção e a preservação dos ecossistemas já existentes. O fato é que as abelhas atuam como polinizadores naturais tanto das espécies nativas como também das cultivadas, promovendo a preservação da biodiversidade e contribuindo com o equilíbrio do ecossistema. Em sintese o projeto tem como meta a expansão no setor apiário na região da AMOC, e conclui-se ser uma atividade economicamente rentável e ecologicamente prudente, a fim de contribuir para o desenvolvimento, gerando emprego e renda para a regiã
Toward an internally consistent astronomical distance scale
Accurate astronomical distance determination is crucial for all fields in
astrophysics, from Galactic to cosmological scales. Despite, or perhaps because
of, significant efforts to determine accurate distances, using a wide range of
methods, tracers, and techniques, an internally consistent astronomical
distance framework has not yet been established. We review current efforts to
homogenize the Local Group's distance framework, with particular emphasis on
the potential of RR Lyrae stars as distance indicators, and attempt to extend
this in an internally consistent manner to cosmological distances. Calibration
based on Type Ia supernovae and distance determinations based on gravitational
lensing represent particularly promising approaches. We provide a positive
outlook to improvements to the status quo expected from future surveys,
missions, and facilities. Astronomical distance determination has clearly
reached maturity and near-consistency.Comment: Review article, 59 pages (4 figures); Space Science Reviews, in press
(chapter 8 of a special collection resulting from the May 2016 ISSI-BJ
workshop on Astronomical Distance Determination in the Space Age
Percepção ambiental dos produtores e qualidade do solo em propriedades orgânicas e convencionais.
O sistema orgânico de produção deve resultar na utilização mais racional dos recursos naturais, sobretudo do solo. Os produtores orgânicos devem adotar práticas conservacionistas, além de atender a outros princípios deste sistema de produção. Neste trabalho foram avaliadas as práticas de manejo e conservação do solo adotadas por produtores orgânicos e convencionais nas regiões dos municípios de Socorro (Serra da Mantiqueira e Mogiana) e Ibiúna, situados no Estado de São Paulo. O objetivo dessa pesquisa foi verificar o grau de adoção de práticas conservacionistas pelos produtores e avaliar a qualidade do solo na agricultura orgânica e convencional. Foi elaborado e aplicado um questionário, com visitas locais para verificação das práticas conservacionistas e ocorrência de erosão, em 30 propriedades. Os resultados foram expressos em índices indicadores de diversidade de uso do solo, atitude conservacionista, percepção de erosão e do impacto sobre os recursos hídricos. Foram também realizadas análises de atributos químicos, físicos e biológicos indicadores da qualidade do solo. Concluiu-se que os produtores orgânicos têm maior percepção quanto à atitude conservacionista e nas propriedades orgânicas há maior diversidade de cultivos, embora não haja maior diversidade geral de uso do solo. A produção orgânica de alface, em Ibiúna proporcionou maior atividade biológica no solo e maior colonização por fungos micorrízicos arbusculares. O sistema orgânico possui maiores teores de matéria orgânica e menores de potássio e não houve diferença entre os atributos físicos do solo dos sistemas orgânico e convencional
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