Decoupled and unidirectional asymptotic models for the propagation of internal waves

We study the relevance of various scalar equations, such as inviscid Burgers', Korteweg-de Vries (KdV), extended KdV, and higher order equations (of Camassa-Holm type), as asymptotic models for the propagation of internal waves in a two-fluid system. These scalar evolution equations may be justified with two approaches. The first method consists in approximating the flow with two decoupled, counterpropagating waves, each one satisfying such an equation. One also recovers homologous equations when focusing on a given direction of propagation, and seeking unidirectional approximate solutions. This second justification is more restrictive as for the admissible initial data, but yields greater accuracy. Additionally, we present several new coupled asymptotic models: a Green-Naghdi type model, its simplified version in the so-called Camassa-Holm regime, and a weakly decoupled model. All of the models are rigorously justified in the sense of consistency

Growth, production and nutrients in coriander cultivated with biofertilizer.

Crescimento, produção e nutrientes no coentro cultivado com biofertilizante. Objetivou-se avaliar o efeito de doses de um biofertilizante de materiais vegetais (BMV) sobre o crescimento, produção e nutrientes no coentro "Verdão"

Invariants and Coherent States for Nonstationary Fermionic Forced Oscillator

The most general form of Hamiltonian that preserves fermionic coherent states stable in time is found in the form of nonstationary fermion oscillator. Invariant creation and annihilation operators and related Fock states and coherent states are built up for the more general system of nonstationary forced fermion oscillator.Comment: 13 pages, Latex, no figure

Palaeobiology, ecology, and distribution of stromatoporoid faunas in biostromes of the mid-Ludlow of Gotland

Six well exposed mid−Ludlow stromatoporoid−dominated reef biostromes in four localities from the Hemse Group in southeastern Gotland, Sweden comprise a stromatoporoid assemblage dominated by four species; Clathrodictyon mohicanum, “Stromatopora” bekkeri, Plectostroma scaniense, and Lophiostroma schmidtii. All biostromes investigated in this area (of approximately 30 km2) are interpreted to belong to a single faunal assemblage forming a dense accumulation of fossils that is probably the best exposed stromatoporoid−rich deposit of the Silurian. The results from this comprehensive study strengthen earlier interpretations of a combination of genetic and environmental control on growth−forms of the stromatoporoids. Growth styles are similar for stromatoporoids in all six biostromes. Differences in biostrome fabric are due to variations in the degree of disturbance by storms. The uniformity of facies and the widespread low−diversity fauna support the view that palaeoenvironmental conditions were similar across the area where these biostromes crop out, and promoted the extraordinary growth of stromatoporoids in this shallow shelf area

Cultivo de hortaliças em várzeas amazônicas: uma técnica tradicional para evitar a água e a umidade.

A Amazônia compreende a maior extensão de floresta tropical úmida do planeta, com área de 6.099.788 km², distribuída nos territórios do Brasil (58,8%), Peru (13%), Colômbia (7,6%), Venezuela (6,5%), Bolívia (5,5%), Guiana (3,1%), Suriname (2,5%), Equador (1,6%) e Guiana Francesa (1,4%) (RAISG, 2015). A região do Brasil inserida na Amazônia continental tem superfície original estimada em 3.587.052 km², abrangendo os estados do Acre, Amapá, Amazonas, Pará, Rondônia e Roraima, sendo definida como zona de ocorrência da Hiléia (Pandolfo, 1994). Mas, em 1953, a abrangência legal da Amazônia brasileira foi estabelecida pela Lei nº 1.806, quando foram incorporados também os territórios dos estados de Tocantins, Mato Grosso e parte do Maranhão (oeste do meridiano 44º) (Brasil, 2016). O bioma amazônico é constituído por distintos ecossistemas, porém dois são mais correntes tanto no meio acadêmico quanto para o público em geral: terra firme e várzea.bitstream/item/170310/1/4900.pd

The lesson of causal discovery algorithms for quantum correlations: Causal explanations of Bell-inequality violations require fine-tuning

An active area of research in the fields of machine learning and statistics is the development of causal discovery algorithms, the purpose of which is to infer the causal relations that hold among a set of variables from the correlations that these exhibit. We apply some of these algorithms to the correlations that arise for entangled quantum systems. We show that they cannot distinguish correlations that satisfy Bell inequalities from correlations that violate Bell inequalities, and consequently that they cannot do justice to the challenges of explaining certain quantum correlations causally. Nonetheless, by adapting the conceptual tools of causal inference, we can show that any attempt to provide a causal explanation of nonsignalling correlations that violate a Bell inequality must contradict a core principle of these algorithms, namely, that an observed statistical independence between variables should not be explained by fine-tuning of the causal parameters. In particular, we demonstrate the need for such fine-tuning for most of the causal mechanisms that have been proposed to underlie Bell correlations, including superluminal causal influences, superdeterminism (that is, a denial of freedom of choice of settings), and retrocausal influences which do not introduce causal cycles.Comment: 29 pages, 28 figs. New in v2: a section presenting in detail our characterization of Bell's theorem as a contradiction arising from (i) the framework of causal models, (ii) the principle of no fine-tuning, and (iii) certain operational features of quantum theory; a section explaining why a denial of hidden variables affords even fewer opportunities for causal explanations of quantum correlation

Observation and Modeling of the Solar Transition Region: II. Solutions of the Quasi-Static Loop Model

In the present work we undertake a study of the quasi-static loop model and the observational consequences of the various solutions found. We obtain the most general solutions consistent with certain initial conditions. Great care is exercised in choosing these conditions to be physically plausible (motivated by observations). We show that the assumptions of previous quasi-static loop models, such as the models of Rosner, Tucker and Vaiana (1978) and Veseckey, Antiochos and Underwood (1979), are not necessarily valid for small loops at transition region temperatures. We find three general classes of solutions for the quasi-static loop model, which we denote, radiation dominated loops, conduction dominated loops and classical loops. These solutions are then compared with observations. Departures from the classical scaling law of RTV are found for the solutions obtained. It is shown that loops of the type that we model here can make a significant contribution to lower transition region emission via thermal conduction from the upper transition region.Comment: 30 pages, 3 figures, Submitted to ApJ, Microsoft Word File 6.0/9

Dynamics of Magnetic Flux Elements in the Solar Photosphere

The interaction of magnetic fields and convection is investigated in the context of the coronal heating problem. We study the motions of photospheric magnetic elements using filtergrams obtained at the Swedish Vacuum Solar Telescope at La Palma. We use potential-field modeling to extrapolate the magnetic and velocity fields to larger height. We find that the velocity in the chromosphere can be locally enhanced at the separatrix surfaces between neighboring flux tubes. The predicted velocities are several km/s, significantly larger than those of the photospheric flux tubes, which may have important implications for coronal heating. sComment: submitted to ApJ, 21 pages, 10 figure

Improving the Project Service Performance of Companies Producing and Marketing Kitchen Systems to Provide Sectoral Competitiveness

At the last stage, solution proposals have been developed by carrying out two additional web-based surveys and in-depth interviews for elimination of the detected problems. The sales/marketing approach of companies, producing and marketing kitchen systems in today's global competitive environment which is only not limited aesthetics, quality and functional performance but also supporting these products with kitchen design services in line with the wishes and requirements of users, has become more and more widespread for sectoral competitiveness and accordingly the issue of kitchen design performance has gained great significance for these types of companies. In this context, scope and objective of the study is to put forward the problems which arise/which may arise in studies conducted in order to determine the wishes and requirements of users which is a part of the project service process of companies producing and marketing kitchen systems and development of solution proposals to eliminate such problems. In line with this defined scope and objective, a web-based survey has been conducted to find out how the designers of a company taken as an example have performed all the related studies to determine the wishes and requirements of users at the first stage as methodology. Subsequently, the results obtained from this survey have been evaluated and the problems have been revealed

Consorciação de couve-de-folha e cariru com uso de biofertilizante e n mineral: produção, uso da terra e renda.

Este presente trabalho objetivou avaliar a consorciação da couve-de-folha com o cariru, utilizando biofertilizante e uréia em cobertura, portanto, em adição à fertilidade residual do solo, em condições de cultivo protegido, visando à agricultura familiar nas condições amazônicas, tendo em vista que esses agricultores desempenham papel crucial e indispensável à diversificação das economias regionais e para a preservação de cultivos tradicionais descartados pela grande escala