The Bering Sea ice cover during March 1979: Comparison of surface and satellite data with the Nimbus-7 SMMR

During March 1979, field operations were carried out in the Marginal Ice Zone (MIZ) of the Bering Sea. The field measurements which included oceanographic, meteorological and sea ice observations were made nearly coincident with a number of Nimbus-7 and Tiros-N satellite observations. The results of a comparison between surface and aircraft observations, and images from the Tiros-N satellite, with ice concentrations derived from the microwave radiances of the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) are given. Following a brief discussion of the field operations, including a summary of the meteorological conditions during the experiment, the satellite data is described with emphasis on the Nimbus-7 SMMR and the physical basis of the algorithm used to retrieve ice concentrations

On the role of actuation for the control of streaky structures in boundary layers

This work deals with the closed-loop control of streaky structures induced by free-stream turbulence in a zero-pressure gradient, transitional boundary layer, by means of localized sensors and actuators. A linear quadratic gaussian regulator is considered along with a system identification technique to build reduced-order models for control. Three actuators are developed with different spatial supports, corresponding to a baseline shape with only vertical forcing, and to two other shapes obtained by different optimization procedures. A computationally efficient method is derived to obtain an actuator which aims to induce the exact structures which are inside the boundary layer, given in terms of their first spectral proper orthogonal decomposition mode, and an actuator that maximizes the energy of induced downstream structures. Two free-stream turbulence levels were evaluated, corresponding to 3.0% and 3.5%, and closed-loop control is applied in large-eddy simulations of transitional boundary layers. All three actuators lead to significant delays in the transition to turbulence and were shown to be robust to mild variations in the free-stream turbulence levels. Differences are understood in terms of the SPOD of actuation and FST-induced fields along with the causality of the control scheme. The actuator optimized to generate the leading downstream SPOD mode, representing the streaks in the open-loop flow, leads to the highest transition delay, which can be understood due to its capability of closely cancelling structures in the boundary layer. However, it is shown that even with the actuator located downstream of the input measurement it may become impossible to cancel incoming disturbances in a causal way, depending on the wall-normal position of the output and on the actuator considered, which limits sensor and actuator placement capable of good closed-loop performance.Comment: 33 pages, 19 figure

Fitotoxicidade de alternativas herbicidas para a cultura do tomate para processamento industrial.

Objetivou-se com este trabalho avaliar a fitotoxicidade de alternativas herbicidas para a cultura do tomate industrial

Open orbifold Gromov-Witten invariants of [C^3/Z_n]: localization and mirror symmetry

We develop a mathematical framework for the computation of open orbifold Gromov-Witten invariants of [C^3/Z_n], and provide extensive checks with predictions from open string mirror symmetry. To this aim we set up a computation of open string invariants in the spirit of Katz-Liu, defining them by localization. The orbifold is viewed as an open chart of a global quotient of the resolved conifold, and the Lagrangian as the fixed locus of an appropriate anti-holomorphic involution. We consider two main applications of the formalism. After warming up with the simpler example of [C^3/Z_3], where we verify physical predictions of Bouchard, Klemm, Marino and Pasquetti, the main object of our study is the richer case of [C^3/Z_4], where two different choices are allowed for the Lagrangian. For one choice, we make numerical checks to confirm the B-model predictions; for the other, we prove a mirror theorem for orbifold disc invariants, match a large number of annulus invariants, and give mirror symmetry predictions for open string invariants of genus \leq 2.Comment: 44 pages + appendices; v2: exposition improved, misprints corrected, version to appear on Selecta Mathematica; v3: last minute mistake found and fixed for the symmetric brane setup of [C^3/Z_4]; in pres

Lift-up, Kelvin-Helmholtz and Orr mechanisms in turbulent jets

Three amplification mechanisms present in turbulent jets, namely lift-up, Kelvin–Helmholtz and Orr, are characterized via global resolvent analysis and spectral proper orthogonal decomposition (SPOD) over a range of Mach numbers. The lift-up mechanism was recently identified in turbulent jets via local analysis by Nogueira et al. (J. Fluid Mech., vol. 873, 2019, pp. 211–237) at low Strouhal number ( St ) and non-zero azimuthal wavenumbers ( m ). In these limits, a global SPOD analysis of data from high-fidelity simulations reveals streamwise vortices and streaks similar to those found in turbulent wall-bounded flows. These structures are in qualitative agreement with the global resolvent analysis, which shows that they are a response to upstream forcing of streamwise vorticity near the nozzle exit. Analysis of mode shapes, component-wise amplitudes and sensitivity analysis distinguishes the three mechanisms and the regions of frequency–wavenumber space where each dominates, finding lift-up to be dominant as St/m→0 . Finally, SPOD and resolvent analyses of localized regions show that the lift-up mechanism is present throughout the jet, with a dominant azimuthal wavenumber inversely proportional to streamwise distance from the nozzle, with streaks of azimuthal wavenumber exceeding five near the nozzle, and wavenumbers one and two most energetic far downstream of the potential core

Manejo químico de plantas daninhas tolerantes ao glyphosate em algodoeiro roundup ready flex

Objetivou-se com este trabalho avaliar o controle de plantas daninhas tolerantes ao glyphosate por meio de diferentes sistemas de manejo químico em algodoeiro Roundup Ready Flex (RF). O experimento está sendo conduzido na área experimental do Instituto Mato-grossense do Algodão localizada no município de Sorriso-MT. A semeadura do algodoeiro cv. IMA 5675BG2RF foi realizada no espaçamento entrelinhas de 0,90 m com população de 90.000 plantas ha -1 . Os tratamentos foram constituidos pela aplicação de glyphosate (1.080 g e.a. ha -1 ), pyrithiobac-sodium (50,4 g i..a. ha -1 ) e trifloxysulfuron-sodium (3,75 g i.a. ha -1 ) em pós-emergência, de forma isolada ou associada aos 15, 35 e 55 dias após a semeadura (DAS) da cultura. O delineamento experimental foi o de blocos completos casualizados, com três repetições. Aos 40 dias após a terceira aplicação em pósemergência, avaliaram-se variáveis relacionadas à fitotoxicidade (escala EWRC) dos tratamentos às plantas de algodoeiro e a porcentagem de controle das plantas (Euphorbia heterophylla, Richardia brasiliensis, Alternanthera tenella e Eleusine indica), por meio de notas visuais de 0 a 100%, em que zero representa ausência de injúrias e 100 a morte das plantas. Três aplicações de glyphosate realizadas aos 15, 35 e 55 DAS do algodoeiro RF apresentam controle satisfatório de todas as espécies infestantes, assim como a aplicação de glyphosate + trifloxysulfuron-sodium aos 15 DAS seguido de glyphosate aos 35 DAS e as associações glyphosate + pyrithiobac-sodium, glyphosate + trifloxysulfuron-sodium e pyrithiobac-sodium + trifloxysulfuron-sodium aplicadas aos 15 DAS seguidas de glyphosate aos 55 DAS. A associação tripla glyphosate + pyrithiobac-sodium + trifloxysulfuron-sodium aplicada aos 35 DAS proporciona excelente controle das plantas daninhas estudas após a aplicação de glyphosate isolado ou pyrithiobac-sodium + trifloxysulfuron-sodium aos 15 DAS

Avaliação da seletividade inicial de herbicidas para o tomateiro por meio da análise de fluorescência da clorofila.

Objetivou-se com este trabalho analisar a fluorescência da clorofila por meio da avaliação da taxa de transporte de eletrons em tomateiro como forma de avaliar a seletividade inicial de hervicidas aplicados em pré-transplate

Identification of GABA receptor genes and evidence of GABA signaling during embryogenesis of the sea urchin

Gamma-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the mammalian central nervous system and acts via ionotropic (GABAA-Rs) and metabotropic (GABAB-Rs) receptors. GABAA-Rs are Cl- selective hetero-pentameric channels assembled by combinations of 19 distinct gene products. Instead, GABAB-Rs are bi-subunit G-protein coupled receptors linked to K+ or Ca2+ channels. Dysfunctions of GABA-signaling (GS) cause psychotic disorders and correlate with epigenetic alterations, such as over-expression of DNA methyl transferase-1 which in turn imposes iper-methylation of GABA-regulated genes. The sea urchin embryo, which presents a rudimentary nervous system, offers a big opportunity to study the GS and its potential epigenetic implications in a simple eukaryote model. To this purpose, we performed a comprehensive in silico analysis of the sea urchin genome and identified a 450 Kb long cluster containing two genes encoding for the GABAB-R subunits, and two genes respectively encoding for a \u3b1/\u3b3/\u3b5-type and a \u3b2/\u3c1/\u3b4/\u3c4/\u3c0-type GABA B A-R subunit. From an evolutionary perspective, this result revealed a unique genomic organization of these genes in sea urchin. Next, to preliminarily evaluate the role of GS during development, Paracentrotus lividus embryos were cultured in the presence of GABA at concentrations ranging from 0.01 to 1.0 mM. Compared to controls, treated embryos showed aberrations in axial patterning, with a dose-dependent effect. In particular, at 48 hours post-fertilization control embryos were normal bilateral symmetric plutei whereas GABA-treated embryos displayed a radial organization with supranumerary spicules. Washout experiments allowed to determine that the period of sensitivity is restricted from the blastula to the gastrula stage. Altogether, these results suggest that dysregulation of GS affects the polarization of the ectoderm. Although preliminary, this study provide the first evidence of GS activity during development of echinoderms

Adaptive Dispersion Compensation for Remote Fiber Delivery of NIR Femtosecond Pulses

We report on remote delivery of 25 pJ broadband near-infrared femtosecond light pulses from a Ti:sapphire laser through 150 meters of single-mode optical fiber. Pulse distortion due to dispersion is overcome with pre-compensation using adaptive pulse shaping techniques, while nonlinearities are mitigated using an SF10 rod for the final stage of pulse compression. Near transform limited pulse duration of 130 fs is measured after the final compression.Comment: 3 pages, 4 figure

Ajuste do espaçamento e da densidade populacional no cultivo rasteiro de tomate destinado ao processamento industrial.

O presente trabalho tevo como objetivo avaliar diferentes combinações de espaçamentos e densidade de platas no desenvolvimento da cultura de tomateiro(BRS Sena) rasteiro destinado à industria.Trabalho 18