Статті в журналах з теми "Ondes propagatives"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Ondes propagatives.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-28 статей у журналах для дослідження на тему "Ondes propagatives".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Wang, Yafei, Koji Yamazaki, and Yasushi Fujiyoshi. "The Interaction between Two Separate Propagations of Rossby Waves." Monthly Weather Review 135, no. 10 (October 1, 2007): 3521–40. http://dx.doi.org/10.1175/mwr3486.1.
Анотація:
Abstract This study deals with two teleconnection patterns and the subsequent wave train propagations during an East Asian summer. Diagnostic results are as follows: 1) a stationary wave ray with zonal wavenumber 5 approximates the arc path linking the correlation centers originating from the Caspian Sea via Lake Baikal to the sea off the southeast coast of Japan (i.e., the OKJ arc path as a focus area) in a pentad correlation map between 500-hPa geopotential height (Z500) and outgoing longwave radiation (OLR) at 30°N, 150°E in June 1979–98. Ray tracing shows that it took 8–10 days for this stationary wave to propagate from an initial position around the Caspian Sea to the focus area, which roughly coincides with the observed case in July 1998. 2) A wave train pattern (P-Ja) observed in the boreal summer propagated along the arc line in the same way as the normal poleward Rossby wave train originating from the Philippines across the North Pacific (P-J), but with a phase shift northeastward of about 90°. 3) Further correlation analyses showed that the P-J-like waves belong mainly to intraseasonal propagating ones while OKJ waves belong mainly to intraseasonal stationary ones. 4) Propagation of the newly observed wave train pattern (P-Ja) occurred following another wave train along the OKJ arc path in mid-July 1998. Both northeastward and southeastward wave propagations merged off the east coast of Japan. 5) The northeastward-propagating wave train observed in mid-July 1998 was triggered by the southeastward-propagating (OKJ) wave train that produced a deep cyclonic circulation and a strong convective activity in the focus area. The link of wave forcing and deep convection was made solely because of a strong upper-level divergence in the focus area.
2
Guesmia, Aissa. "Non-exponential and polynomial stability results of a Bresse system with one infinite memory in the vertical displacement." Nonautonomous Dynamical Systems 4, no. 1 (October 26, 2017): 78–97. http://dx.doi.org/10.1515/msds-2017-0008.
Анотація:
Abstract The asymptotic stability of one-dimensional linear Bresse systems under infinite memories was obtained by Guesmia and Kafini [10] (three infinite memories), Guesmia and Kirane [11] (two infinite memories), Guesmia [9] (one infinite memory acting on the longitudinal displacement) and De Lima Santos et al. [6] (one infinite memory acting on the shear angle displacement). When the kernel functions have an exponential decay at infinity, the obtained stability estimates in these papers lead to the exponential stability of the system if the speeds ofwave propagations are the same, and to the polynomial one with decay rate otherwise. The subject of this paper is to study the case where only one infinite memory is considered and it is acting on the vertical displacement. As far as we know, this case has never studied before in the literature. We show that this case is deeply different from the previous ones cited above by proving that the exponential stability does not hold even if the speeds of wave propagations are the same and the kernel function has an exponential decay at infinity. Moreover, we prove that the system is still stable at least polynomially where the decay rate depends on the smoothness of the initial data. For classical solutions, this decay rate is arbitrarily close to . The proof is based on a combination of the energy method and the frequency domain approach to overcome the new mathematical difficulties generated by our system.
3
Jabiri, Ayoub, Abdelali Yacoubi, and Mhammed El Allami. "Plotting Lamb waves dispersion curves of an aluminum plate by the Semi-Analytical Finite Element (SAFE) method and comparison with analytical curves." ITM Web of Conferences 48 (2022): 02006. http://dx.doi.org/10.1051/itmconf/20224802006.
Анотація:
It is well known that the propagation of Lamb waves in elastic solid medias depends on the frequency and on the material properties, but it does not depend on the propagation direction in isotropic medias and gives rise to two basic types of modes, symmetric and antisymmetric ones. This paper presents an application of the semi-analytical finite element (SAFE) method on an isotropic aluminum plate of thickness e = 2mm. The main goal of this paper is to make a quantitative evaluation of the SAFE method by carrying out the following tasks: a) calculation of the dispersion curves (wavenumber, phase velocity, group velocity, b) calculation of the relative error and validation of the proposed algorithm, c) comparison between the curves obtained by SAFE method on those obtained by Bisection method. It should be noted here that our study is restricted on the propagative modes.
4
Nascimento, Ana Rosa Peixoto, and Rosa de Lima Ramos Mariano. "Cancro bacteriano da videira: etiologia, epidemiologia e medidas de controle." Ciência Rural 34, no. 1 (February 2004): 301–7. http://dx.doi.org/10.1590/s0103-84782004000100050.
Анотація:
No início de 1998, o cancro bacteriano da videira, causado pela bactéria Xanthomonas campestris pv. viticola, foi detectado pela primeira vez, no Brasil, em parreirais do Submédio São Francisco, onde a doença vem ocasionando prejuízos nas cultivares suscetíveis Red Globe, Itália, Festival, Brasil, Piratininga, Patrícia, Benitaka e Catalunha. Os sintomas, nas folhas, surgem como pontos necróticos (1 a 2mm de diâmetro) com ou sem halos amarelados, algumas vezes coalescendo e causando a morte de extensas áreas do limbo foliar. Nas nervuras e pecíolos, nos ramos e ráquis dos frutos, formam-se manchas escuras alongadas que evoluem para fissuras longitudinais de coloração negra conhecidas como cancros. Descoloração vascular é também observada. As bagas são desuniformes em tamanho e cor podendo apresentar lesões necróticas. A disseminação do patógeno ocorre através de material propagativo infectado, material de colheita (contentores, tesouras de poda e raleio, luvas), tratos culturais (desbrota, poda, raleio de bagas, colheita), ventos e chuvas. Apesar da região apresentar um curto período chuvoso, a disseminação da bactéria é mais eficiente durante essa época. Em condições de umidade e temperatura elevadas, o patógeno sobrevive em restos de cultura. Para o controle da doença, recomenda-se o uso de material propagativo sadio, inspeção no campo, poda drástica de órgãos infectados, eliminação de plantas severamente infectadas, condução da época de poda de produção, desinfestação de veículos, de equipamentos e de materiais para poda, utilização de fungicidas protetores cúpricos e tiocarbamatos, e utilização de quebra-ventos para reduzir a disseminação do patógeno.
5
Noor, Saima, Ma’mon Abu Hammad, Rasool Shah, Albandari W. Alrowaily, and Samir A. El-Tantawy. "Numerical Investigation of Fractional-Order Fornberg–Whitham Equations in the Framework of Aboodh Transformation." Symmetry 15, no. 7 (July 3, 2023): 1353. http://dx.doi.org/10.3390/sym15071353.
Анотація:
In this investigation, the fractional Fornberg–Whitham equation (FFWE) is solved and analyzed via the variational iteration method (VIM) and Adomian decomposition method (ADM) with the help of the Aboodh transformation (AT). The FFWE is an important model for describing several nonlinear wave propagations in various fields of science and plasma physics. The AT provides a powerful tool for transforming fractional-order differential equations (DEs) into integer-order ones, making them more amenable to analytical solutions. Accordingly, the main objective of this investigation is to demonstrate the effectiveness and accuracy of ADM and VIM in deriving some approximations for the FFWE. Furthermore, we highlight the advantages and potential applications of these methods in solving other fractional-order nonlinear problems in several scientific fields, especially in plasma physics and some engineering problems.
6
Zhang, Guoqiang, Zhenya Yan, and Li Wang. "The general coupled Hirota equations: modulational instability and higher-order vector rogue wave and multi-dark soliton structures." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, no. 2222 (February 2019): 20180625. http://dx.doi.org/10.1098/rspa.2018.0625.
Анотація:
The general coupled Hirota equations are investigated, which describe the wave propagations of two ultrashort optical fields in a fibre. Firstly, we study the modulational instability for the focusing, defocusing and mixed cases. Secondly, we present a unified formula of high-order rational rogue waves (RWs) for the focusing, defocusing and mixed cases, and find that the distribution patterns for novel vector rational RWs of focusing case are more abundant than ones in the scalar model. Thirdly, the N th-order vector semirational RWs can demonstrate the coexistence of N th-order vector rational RWs and N breathers. Fourthly, we derive the multi-dark-dark solitons for the defocsuing and mixed cases. Finally, we derive a formula for the coexistence of dark solitons and RWs. These results further enrich and deepen the understanding of localized wave excitations and applications in vector nonlinear wave systems.
7
Spinelli, Victor Mouzinho, Luis Iram Coutinho Ulguim, Ilisandra Zanandrea, Valmor João Bianchi, Willian Silva Barros, Luís Eduardo Panozzo, Moisés Botelho Fabião, and Deivid Araújo Magano. "Teste de germinação em Seedlings de porta-enxertos de pessegueiro." OBSERVATÓRIO DE LA ECONOMÍA LATINOAMERICANA 21, no. 8 (August 25, 2023): 9804–16. http://dx.doi.org/10.55905/oelv21n8-106.
Анотація:
O objetivo deste trabalho foi caracterizar o potencial germinativo de sementes de porta-enxertos de pessegueiro. O material propagativo constituiu-se de caroços das cultivares de porta-enxertos ‘Capdeboscq’ ‘Tsukuba 1’, ‘Tsukuba 2’, ‘Tsukuba 3’, ‘Okinawa Roxo’ e dos híbridos intraespecíficos de P. persica, seleções ‘NR 0280401’ (híbrido F1 derivado do cruzamento ‘Flordaguard’ x ‘Capdeboscq’), ‘NR 0080412’ (híbrido F1 derivado do cruzamento ‘Capdeboscq’ x ‘Flordaguard’), ‘NR 0050303’ (híbrido F1 derivado do cruzamento ‘Capdeboscq’ x ‘Tsukuba 1’) e ‘NR 0300402’ (híbrido F1 derivado do cruzamento ‘Flordaguard’ x ‘Nemaguard’) foram estratificadas em BOD, na ausência de luz, onde permaneceram por até 28 dias. Verificou-se que as sementes das seleções de porta-enxertos ‘NR 0280401’, ‘NR 0080412’ e da cv. ‘Capdeboscq’ requerem menor tempo para a germinação e apresentam maior percentual de sementes germinadas. Genótipos com maturação de frutos mais precoces, o período de armazenamento deve ser menor, devido à perda viabilidade, conforme verificado para ‘Okinawa Roxo’.
8
Granot, Er'el. "Analytical Solutions for the Propagation of UltraShort and UltraSharp Pulses in Dispersive Media." Applied Sciences 9, no. 3 (February 4, 2019): 527. http://dx.doi.org/10.3390/app9030527.
Анотація:
Ultrashort pulses are severely distorted even by low dispersive media. While the mathematical analysis of dispersion is well known, the technical literature focuses on pulses, Gaussian and Airy pulses, which keep their shape. However, the cases where the shape of the pulse is unaffected by dispersion is the exception rather than the norm. It is the objective of this paper to present a variety of pulse profiles, which have analytical expressions but can simulate real-physical pulses with great accuracy. In particular, the dynamics of smooth rectangular pulses, physical Nyquist-Sinc pulses, and slowly rising but sharply decaying ones (and vice versa) are presented. Besides the usage of this paper as a handbook of analytical expressions for pulse propagations in a dispersive medium, there are several new findings. The main findings are the analytical expressions for the propagation of chirped rectangular pulses, which converge to extremely short pulses; an analytical approximation for the propagation of super-Gaussian pulses; the propagation of the Nyquist-Sinc Pulse with smooth spectral boundaries; and an analytical expression for a physical realization of an attenuation compensating Airy pulse.
9
Castellanos, Luis M., Francisco Lopez, and Erick Reyes - Vera. "Metamateriales: principales características y aplicaciones." Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 40, no. 156 (October 3, 2016): 395. http://dx.doi.org/10.18257/raccefyn.345.
Анотація:
Las propiedades electromagnéticas de todos los materiales existentes en la naturaleza pueden ser determinadas a partir dos parámetros: la permeabilidad magnética µ y la permitividad eléctrica ε. Estos dos parámetros caracterizan la respuesta del material cuando interactúa con la radiación electromagnética. En principio, no existe límite alguno para el rango de valores posibles que pueden tomar µ y ε, por lo cual podemos pensar en diseñar y construir a voluntad materiales con características de respuesta electromagnética especificas (es decir µ y ε) no encontradas en la naturaleza. Estos materiales fabricados en el laboratorio reciben el nombre genérico de metamateriales, y entre ellos se encuentran los conocidos por sus siglas en ingles LHM (Left Handed Materials), así llamados porque los vectores de campo , de las Ondas Electromagnéticas que viajan en su interior están relacionados por la regla de la mano izquierda. La característica distintiva de los LHM es que para ciertas bandas de frecuencia presentan índice de refracción negativo ( ) con modos propagativos posibles solamente si ambos parámetros µ y ε, dentro de dichas bandas de frecuencias son negativos. El propósito de este trabajo es presentar los principios y fundamentos de estos metamateriales de manera que despierte el interés de lectores no especializados. © 2016. Acad. Colomb. Cienc. Ex. Fis. Nat.<div id="spoon-plugin-kncgbdglledmjmpnikebkagnchfdehbm-2" style="display: none;"> </div>
10
Silva, Tamires Maria De Lima, and Emilio Augusto Gomes de Oliveira. "“Maquiagem verde” na comunicação gráfica de condomínios residenciais em Caruaru-Pernambuco." AtoZ: novas práticas em informação e conhecimento 2, no. 2 (December 31, 2013): 116. http://dx.doi.org/10.5380/atoz.v2i2.41326.
Анотація:
Introdução: O termo greenwashing (“maquiagem verde”), é utilizado para denominar o modo de comunicação desenvolvido por empreendedores ao tentar mascarar as verdades que permeiam seus produtos e serviços, o que pode denotar um fraco comprometimento ambiental. Com base na análise de meios gráficos propagativos de atributos sustentáveis de condomínios residenciais no município de Caruaru, Pernambuco visou-se compreender até que ponto o greenwashing está presente na propaganda deste segmento de mercado na Região. Método: Realizou-se uma pesquisa de campo, entre janeiro e março de 2012 em pontos de vendas de empreendimentos imobiliários, utilizando-se peças publicitárias de divulgação dos empreendimentos complementada por conversas informais com corretores e outras pessoas responsáveis pela comercialização destes. Entre os materiais gráficos disponíveis destacam-se os sites web dos empreendimentos, os folderes, catálogos e outdoors, e os estandes de venda. Resultados: Todos os empreendimentos analisados apresentaram determinado grau de inserção no contexto estabelecido para os “seis pecados do greenwashing” bem como no artigo 36º. do CONAR, referente à infração da autenticidade publicitária em seus meios gráficos. Conclusão: O crescimento exponencial da cidade de Caruaru atraiu empreendimentos dos mais diversificados setores. Contudo, urge pensar que uma cidade ao ser moldada para novos olhares e conceitos de vida, deve unicamente desenvolver-se em concordância com ações de fato consolidadas em um transparente desenvolvimento sustentável, onde todos os interessados sejam verdadeiramente contemplados.
11
Araújo, Jéssica Conceição, Izabel Cristina Moreira, and Solange Xavier-Santos. "Myxobiota associada a resíduos de Mangueira (Mangifera indica l., Anacardiaceae)." Heringeriana 6, no. 1 (October 22, 2014): 20–22. http://dx.doi.org/10.17648/heringeriana.v6i1.13.
Анотація:
Os Mixomicetos (Reino Protista, Filo Myxomycota) constituem um grupo homogêneo de organismos comumente encontrados em lugares sombrios, úmidos e frescos, onde haja matéria orgânica em decomposição. Apresentam como características distintivas em seu ciclo de vida uma fase em forma de massa protoplasmática, multinucleada, acelular e de vida livre chamada de plasmódio e uma fase propagativa, o corpo de frutificação. Esses organismos são capazes de se desenvolver sobre diversos tipos de substratos, tais como troncos, folhas, fungos e excrementos em decomposição. O objetivo deste trabalho foi verificar as espécies que ocorrem em resíduos de mangueira (Mangifera indica). Foram realizadas coletas em amontoados residuais dessa planta, tanto em uma área urbana (quintal residencial) do município de Anápolis e em uma área rural (Fazenda Santa Rita), no município de Pirenópolis, Goiás, Brasil. Um total de nove espécies de mixomicetos foi encontrado; as quais estão distribuídas em duas famílias e uma única ordem: Physarales: Didymiaceae (Diderma hemisphaericum, D. saundersii, D. cf effusum e Diachea leucopodia) e Physaraceae (Craterium aureum, Didymium comatum, D. cf. flexuosum, Physarum melleume e P pusillum), demonstrando que os resíduos de mangueira constituem um substrato propício ao desenvolvimento e frutificação de mixomicetos.
12
Lisboa, Rodrigo C., Paulo R. F. Teixeira, and Eric Didier. "Regular and Irregular Wave Propagation Analysis in a Flume with Numerical Beach Using a Navier-Stokes Based Model." Defect and Diffusion Forum 372 (March 2017): 81–90. http://dx.doi.org/10.4028/www.scientific.net/ddf.372.81.
Анотація:
This paper describes the analysis of the propagation of regular and irregular waves in a flume by using Fluent® model, which is based on the Navier-Stokes (NS) equations and employs the finite volume method and the Volume of Fluid (VoF) technique to deal with two-phase flows (air and water). At the end of the flume, a numerical beach is used to suppress wave reflections. The methodology consists of adding a damping sink term to the momentum equation. In this study, this term is calibrated for three cases of regular incident waves (H = 1 m, T = 5, 7.5, and 12 s) by varying the linear and quadratic damping coefficients of the formulation. In general, while lower values of damping coefficients cause residuals on the free surface elevation due to wave interactions with the outlet boundary, reflection occurs on the numerical beach when higher values are used. A range of optimal damping coefficients are found considering one of them null. In one of these cases, temporal series of free surface elevation are compared with theoretical ones and very good agreement is reached. Afterwards, an irregular wave propagation, characterized by a JONSWAP spectrum, is investigated. Several gauges along the flume are evaluated and good agreement between the spectrum obtained numerically and the ones imposed at beginning of the flume is verified. This study shows the capacity of NS models, such as Fluent®, to simulate adequately regular and irregular wave propagations in a flume with numerical beach to avoid reflections.
13
Cueva-Agila, Augusta Yadira, and Rino Cella. "Agrobacterium-mediated transformation of the wild orchid Cattleya maxima Lindl." Universitas Scientiarum 23, no. 1 (March 22, 2018): 89. http://dx.doi.org/10.11144/javeriana.sc23-1.amto.
Анотація:
Protocorms are unique anatomical structures; they are akin to rhizoids and are formed by young orchid seedlings under physiological conditions. Explanted orchid tissues produce similar structures called protocorm-like bodies (PLBs) when exposed to appropriate <em>in vitro</em> growing conditions. Both the propagative nature of PLBs and the easiness by which they can be generated, make these structures an attractive alternative to seed-mediated production for growing large numbers of plants. To increase somatic embryogenesis and optimize the procedure, PLBs of <em>Cattleya maxima </em>were transformed<em> </em>using the <em>Agrobacterium tumefaciens </em>method. The T-DNA carried a Hygromycin-resistance gene, a visible marker (GFP5-GUSA) and a rice gene encoding the Somatic Embryogenesis Receptor Kinase, deemed to be important for somatic embryogenesis. Treated PLBs generated somatic embryos developing Hygromycin-resistant plantlets. The insertion of T-DNA was confirmed by PCR, and GFP expression was observed using a fluorescent stereomicroscope. Transformed <em>Cattleya maxima</em> PLBs were more efficient in forming somatic embryos (60-80%) than untransformed controls (45-57%), and this contrast was maximized in hormone-free, Murashige and Skoog (MS) medium (80% of the transformed plants compared to 57% of the untransformed ones). This finding supports the notion that SERK<em> </em>plays an important role in Orchid embryogenesis.
14
Lee, Hyoung In, and El Hang Lee. "The Minimum Wave Damping Selects the Most Favored Solution from Multiple Ones to Acoustic-Like Problems." Materials Science Forum 673 (January 2011): 11–20. http://dx.doi.org/10.4028/www.scientific.net/msf.673.11.
Анотація:
Back in 1990, D. S. Stewart and the first author contributed significantly to understanding the one-dimensional stability of detonation waves [1]. For this purpose, the reactive Euler’s equation with the one-component reaction term was linearized around the steady state of the well-known ZND (Zeldovich-Doering-von Neumann) model. The key aspect of this paper was to derive the linearized radiation condition (named after A. Sommerfeld). They numerically found multiple eigenvalues for pairs of the temporal frequency and temporal attenuation rate (TAR). Of course, the propagating-wave mode having the least value of the TAR (in the sense of its absolute value) was selected. The successful numerical implementation of the far-field radiation condition is a must when it comes to incorporating a large surrounding space into a problem of finite extent. To one of the sure examples in this category belong the problems involving detonation waves, where high-energy-rate processes take place in spatially confined spaces while the surrounding space should be taken into account for reasons of energy loss (or leaky waves in the language of optics). In another fascinating area of science is nano-photonics, where energy transport should be handled in highly confined regions of space, yet being surrounded by unbounded (dielectric) media. The total energy release in nano-photonics is certainly much smaller than that involved in detonation. However, the energy per unit nanometer-scale volume is not negligibly small in nano-photonics. Over the years, the first author has been successful in implementing both theory and numerical methods to find a multitude of eigenvalues in optics [2]. In this case, the governing Maxwell’s equations are already in a linearized form, being in a sense similar to the linearized Euler equations. In addition, the noble metals such as gold and silver are instrumental in enhancing local electric-field intensities, for which the science of plasmonics is being vigorously investigated in nano-photonics. Even the Bloch’s hydrodynamic equation describing the collective motion of the electrons is akin to the Navier-Stokes equations [3]. Meanwhile, assuming a real-valued frequency has been an old tradition in optics, partly because the real-valued photon’s energy is proportional to frequency and normally the continuous-wave (cw) approximation holds true. In a radical departure from this optical scientists’ tradition, we have recently attempted to deal with complex-valued frequencies in examining the wave propagations around nanoparticles [4, 5]. In consequence, the stability of multiple propagating waves was successfully determined for selecting most realizable wave mode. Further interesting points of the interplay between the two seemingly disparate branches of science (fluid dynamics and photonics) will be expounded in this talk.
15
Costa, Frederico Henrique da Silva, Moacir Pasqual, Hermínio Souza Rocha, Jonny Everson Scherwinski Pereira, Evaristo Mauro de Castro, and Luzia Yuriko Miyata. "Crescimento e anatomia foliar de bananeiras submetidas a diferentes condições de cultivo in vitro." Bragantia 68, no. 2 (2009): 303–11. http://dx.doi.org/10.1590/s0006-87052009000200003.
Анотація:
A realização de pesquisas que possibilitem redução dos custos de produção e ou melhoria na qualidade das mudas micropropagadas tem sido imprescindível para possibilitar a utilização e difusão deste tipo de material propagativo. O objetivo deste trabalho foi avaliar a influência de alterações no ambiente de cultivo sobre o crescimento e anatomia de bananeiras na fase de alongamento/enraizamento in vitro. Para tanto, brotações axilares das cultivares Caipira e Pacovan foram cultivadas em meio MS contendo ANA (1 mg L-1) e agar (6 g L-1), onde foram aplicados os tratamentos. Os tratamentos consistiram de concentrações de sacarose (15 g L-1 e 30 g L-1) e ambientes de cultivo (Natural - casa de vegetação e Artificial - sala de crescimento). No fim de 45 dias, foram determinadas características de crescimento e de anatomia foliar. Houve influência significativa das alterações no ambiente de cultivo in vitro sobre as características avaliadas. Verificou-se que o uso da luz natural associada a 15 g L-1 de sacarose para a cultivar Caipira e 30 g L-1 para a Pacovan pode ser utilizada satisfatoriamente na fase de alongamento/enraizamento in vitro. Maior espessamento dos parênquimas clorofilianos e incremento na densidade estomática são induzidos em ambiente natural. A luz natural como alternativa às lâmapadas fluorescentes, no alongamento/enraizamento in vitro, representa potencial para reduzir os custos de produção e promover melhorias na anatomia foliar das mudas micropropagadas.
16
Chen, Ge, Xiaoyan Chen, and Chuanchuan Cao. "Divergence and Dispersion of Global Eddy Propagation from Satellite Altimetry." Journal of Physical Oceanography 52, no. 4 (April 2022): 705–22. http://dx.doi.org/10.1175/jpo-d-21-0122.1.
Анотація:
Abstract It is well understood that isolated eddies are presumed to propagate westward intrinsically at the speed of the annual baroclinic Rossby wave. This classic description, however, is known to be frequently violated in both propagation speed and its direction in the real ocean. Here, we present a systematic analysis on the divergence of eddy propagation direction (i.e., global pattern of departure from due west) and dispersion of eddy propagation speed (i.e., zonal pattern of departure from Rossby wave phase speed). Our main findings include the following: 1) A global climatological phase map (the first of its kind to our knowledge) indicating localized direction of most likely eddy propagation has been derived from 28 years (1993–2020) of satellite altimetry, leading to a leaf-like full-angle pattern in its overall divergence. 2) A meridional deflection map of eddy motion is created with prominent equatorward/poleward deflecting zones identified, revealing that it is more geographically correlated rather than polarity determined as previously thought (i.e., poleward for cyclonic eddies and equatorward for anticyclonic ones). 3) The eddy–Rossby wave relationship has a duality nature (waves riding by eddies) in five subtropical bands centered around 27°N and 26°S in the two hemispheres, outside which their relationship has a dispersive nature with dominant waves (eddies) propagating faster in the tropical (extratropical) oceans. Current, wind, and topographic effects are major external forcings responsible for the observed divergence and dispersion of eddy propagations. These results are expected to make a significant contribution to eddy trajectory prediction using physically based and/or data-driven models.
17
Teodoro, Mauro Sergio, and Pedro Pereira Neves. "Banco de sementes de adubos verdes / Seed bank of green manures." Brazilian Journal of Animal and Environmental Research 5, no. 1 (March 22, 2022): 1279–85. http://dx.doi.org/10.34188/bjaerv5n1-097.
Анотація:
A adubação verde é uma prática agrícola utilizada há mais de 2.000 anos por chineses, gregos e romanos, para aumentar a produção das lavouras. Do ponto de vista tecnológico e ambiental, a prática contribui para a proteção do solo contra a erosão e a radiação solar, permitindo o aumento do seu teor de matéria orgânica. Promove, também, a descompactação, estruturação e aeração do solo, resultando no aumento da capacidade de armazenamento de água e nutrientes. No Brasil, os primeiros estudos foram realizados no Instituto Agronômico (IAC), no Estado de São Paulo, sendo obtidos resultados muitos positivos neste estado, entretanto, vale ressaltar que não existem recomendações de uso apropriadas para a região Nordeste. Empresas que trabalham com leguminosas possuem como referência somente as regiões Sudeste, Sul e Centro-Oeste. A adubação verde pode contribuir para a redução do custo de produção e diminuir a dependência de insumos externos, mas é necessário ações de pesquisa para validação dessas tecnologias para as condições da região. Isto se reflete nas unidades de produção agrícola, onde os agricultores encontram dificuldades para ajustar o uso dos adubos verdes nos seus sistemas de produção. Entre os principais entraves para a utilização da adubação verde no Brasil tem sido a baixa disponibilidade de informações a respeito de características, benefícios e formas de utilização, principalmente para os agricultores familiares, mas especificamente no caso do nordeste, a carência de material propagativo tem sido um desafio, o que justificou a implantação do “banco de sementes” para amenizar este quadro.
18
Xie, Xi-Yang, and Gao-Qing Meng. "Dark-soliton collisions for a coupled AB system in the geophysical fluids or nonlinear optics." Modern Physics Letters B 32, no. 04 (February 9, 2018): 1850039. http://dx.doi.org/10.1142/s0217984918500392.
Анотація:
Under investigation in this paper is a coupled AB system, which describes the marginally unstable baroclinic wave packets in the geophysical fluids or ultra-short pulses in nonlinear optics. As the dark solitons are more resistant against various perturbations than the bright ones, we aim to investigate the dark solitons in the geophysical fluids or nonlinear optics. Dark one- and two-soliton solutions for such a system are derived based on the bilinear forms and propagations of the one solitons and collisions between the two solitons are graphically illustrated and analyzed. Further, influences of the coefficients [Formula: see text] and [Formula: see text] on the solitons are discussed, where [Formula: see text] is a parameter measuring the state of the basic flow and [Formula: see text] is the group velocity. The dark-one solitons with invariant shapes and amplitudes are viewed, and elastic collisions between the dark-two solitons are observed. Also, elastic collision between the bright and dark solitons is viewed, and the dark soliton is found to possess two peaks. [Formula: see text] is found to affect the widths of the dark-one solitons and the travelling directions of the dark-two solitons. It is shown that [Formula: see text] cannot influence shapes of [Formula: see text] and [Formula: see text], but affect the plane of the one soliton for [Formula: see text], and the two-peak dark soliton for [Formula: see text] changes to the single-peak one with the value of [Formula: see text] decreasing, where [Formula: see text] and [Formula: see text] are the packets of short waves and [Formula: see text] is the mean flow.
19
Panontin, Juliane Farinelli, Domingos Marques Ferreira Neto, Natália Belo Moreira Morbeck, and Áurea Welter. "RELAÇÃO ENTRE ÍNDICE DE DESENVOLVIMENTO HUMANO E NÚMERO DE CASOS DE COVID-19 EM CIDADES DO TOCANTINS." Singular. Saúde e Biológicas 1, no. 2 (December 15, 2021): 23–27. http://dx.doi.org/10.33911/singularsb.v1i2.124.
Анотація:
No final do ano de 2019, aproximadamente em dezembro, aparece uma nova enfermidade do trato respiratório bastante propagativa na China, nomeada de COVID-19, a qual se alastrou ligeiramente por diversos países fazendo com que a Organização Mundial da Saúde (OMS) decretasse estado de pandemia. Cidades que apresentam uma maior vulnerabilidade podem apresentar uma disseminação maior da COVID-19. O presente estudo teve como objetivo relacionar o IDH com o número de casos de COVID-19 em cidades tocantinenses. Para tanto, foi realizado um estudo descritivo retrospectivo, exploratório, no qual foram analisados 20 municípios do estado do Tocantins, selecionando os 10 municípios com maior IDH e os 10 municípios com menor IDH, de acordo com censo de 2010. Os dados coletados foram tabulados no software Excel e foi realizada análise de correlação no R 4.1.1. Foi usado a correlação de Spearman no programa R version 4.1.1 onde o valor obtido de ρ(rho) foi analisado. A partir dos resultados obtidos, observa-se que o IDH da cidade tem relação com o índice de casos por 1.000 habitantes, quando for levado em consideração o número de incidência, pois os seis primeiros municípios com maior taxa de incidência pela COVID-19 têm um IDH alto, ou seja, quando feito a correlação dos dados levando em consideração o número de incidência de casos em todas as cidades relacionado ao IDH, verificou-se que cidades com maior população apresentaram uma proliferação maior da COVID-19. Com o levantamento realizado, verificou-se que no Tocantins, a disseminação da COVID-19 em relação ao IDH, foi bem maior em cidades IDH alto devido, possivelmente à maior movimentação de pessoas.
20
Madden, L. V., M. J. Jeger, and F. van den Bosch. "A Theoretical Assessment of the Effects of Vector-Virus Transmission Mechanism on Plant Virus Disease Epidemics." Phytopathology® 90, no. 6 (June 2000): 576–94. http://dx.doi.org/10.1094/phyto.2000.90.6.576.
Анотація:
A continuous-time and deterministic model was used to characterize plant virus disease epidemics in relation to virus transmission mechanism and population dynamics of the insect vectors. The model can be written as a set of linked differential equations for healthy (virus-free), latently infected, infectious, and removed (postinfectious) plant categories, and virus-free, latent, and infective insects, with parameters based on the transmission classes, vector population dynamics, immigration/emigration rates, and virus-plant interactions. The rate of change in diseased plants is a function of the density of infective insects, the number of plants visited per time, and the probability of transmitting the virus per plant visit. The rate of change in infective insects is a function of the density of infectious plants, the number of plants visited per time by an insect, and the probability of acquiring the virus per plant visit. Numerical solutions of the differential equations were used to determine transitional and steady-state levels of disease incidence (d*); d* was also determined directly from the model parameters. Clear differences were found in disease development among the four transmission classes: nonpersistently transmitted (stylet-borne [NP]); semipersistently transmitted (foregut-borne [SP]); circulative, persistently transmitted (CP); and propagative, persistently transmitted (PP), with the highest disease incidence (d) for the SP and CP classes relative to the others, especially at low insect density when there was no insect migration or when the vector status of emigrating insects was the same as that of immigrating ones. The PP and CP viruses were most affected by changes in vector longevity, rates of acquisition, and inoculation of the virus by vectors, whereas the PP viruses were least affected by changes in insect mobility. When vector migration was explicitly considered, results depended on the fraction of infective insects in the immigration pool and the fraction of dying and emigrating vectors replaced by immigrants. The PP and CP viruses were most sensitive to changes in these factors. Based on model parameters, the basic reproductive number (R0)—number of new infected plants resulting, from an infected plant introduced into a susceptible plant population—was derived for some circumstances and used to determine the steady-state level of disease incidence and an approximate exponential rate of disease increase early in the epidemic. Results can be used to evaluate disease management strategies.
21
Lari, Giacomo, Melaine Saillenfest, and Marco Fenucci. "Long-term evolution of the Galilean satellites: the capture of Callisto into resonance." Astronomy & Astrophysics 639 (July 2020): A40. http://dx.doi.org/10.1051/0004-6361/202037445.
Анотація:
Context. The Galilean satellites have very complex orbital dynamics due to the mean-motion resonances and the tidal forces acting in the system. The strong dissipation in the couple Jupiter–Io is spread to all the moons involved in the so-called Laplace resonance (Io, Europa, and Ganymede), leading to a migration of their orbits. Aims. We aim to characterize the future behavior of the Galilean satellites over the Solar System lifetime and to quantify the stability of the Laplace resonance. Tidal dissipation permits the satellites to exit from the current resonances or be captured into new ones, causing large variation in the moons’ orbital elements. In particular, we want to investigate the possible capture of Callisto into resonance. Methods. We performed hundreds of propagations using an improved version of a recent semi-analytical model. As Ganymede moves outwards, it approaches the 2:1 resonance with Callisto, inducing a temporary chaotic motion in the system. For this reason, we draw a statistical picture of the outcome of the resonant encounter. Results. The system can settle into two distinct outcomes: (A) a chain of three 2:1 two-body resonances (Io–Europa, Europa–Ganymede, and Ganymede–Callisto), or (B) a resonant chain involving the 2:1 two-body resonance Io–Europa plus at least one pure 4:2:1 three-body resonance, most frequently between Europa, Ganymede, and Callisto. In case A (56% of the simulations), the Laplace resonance is always preserved and the eccentricities remain confined to small values below 0.01. In case B (44% of the simulations), the Laplace resonance is generally disrupted and the eccentricities of Ganymede and Callisto can increase up to about 0.1, making this configuration unstable and driving the system into new resonances. In all cases, Callisto starts to migrate outward, pushed by the resonant action of the other moons. Conclusions. From our results, the capture of Callisto into resonance appears to be extremely likely (100% of our simulations). The exact timing of its entrance into resonance depends on the precise rate of energy dissipation in the system. Assuming the most recent estimate of the dissipation between Io and Jupiter, the resonant encounter happens at about 1.5 Gyr from now. Therefore, the stability of the Laplace resonance as we know it today is guaranteed at least up to about 1.5 Gyr.
22
Li, Yulaing, Wei Zhao, Wenqi Zhang, and Meng Chen. "A dynamic model for engineering change propagations in multiple product development stages." Artificial Intelligence for Engineering Design, Analysis and Manufacturing 36 (2022). http://dx.doi.org/10.1017/s089006042100041x.
Анотація:
Abstract To accurately predict propagation dynamics for single or multiple change propagations across different product development stages in a sequential or concurrent way is critical for decision-making of implementing change requests. In this paper, a change propagation dynamic model is built based on the compartmentalization of engineering entities into susceptible engineering entities and affected engineering entities (SA), the ordinary differential equations for describing the rate of affected entities with respect to the total ones and the duration for resolving all the changes for every moment are presented by combining the calculations of change impacts with different split and joint junctions. Considering the difficulty of finding analytical solutions to the differential equations, algorithms for sequential and concurrent simulations of change propagations across different development stages, and random and GA (Genetic Algorithm)-based optimal selections of feasible propagation paths are developed to obtain numerical solutions for single and multiple change requests. Simulation results show that change ripples and blossoms can be observed in both sequential and concurrent change propagations, and these propagation patterns are not sensitive to the initial change effect and the threshold value for propagations, while critical change propagation paths and the number of initiated changes have important effects on both concurrent and sequential change propagation process. It is also demonstrated that concurrent propagation strategy is advantageous for processing single or few of initiated changes since it can shorten product redevelopment time, sequential propagation strategy has an advantage of robustness for handling multiple initiated change requests.
23
Fu, Zhenlin, Riyi Zheng, Jialuo Liang, Jiuyang Lu, Weiyin Deng, Man-Zhu Ke, Xueqin Huang, and Zhengyou Liu. "Pseudomagnetic fields in bilayer phononic crystals." Europhysics Letters, May 3, 2024. http://dx.doi.org/10.1209/0295-5075/ad473d.
Анотація:
Abstract Pseudomagnetic field (PMF), as an artificial gauge field, has attracted widespread attention in the exploration of magnetic-like effects in artificial structural materials. It offers a novel mechanism for manipulating wave fields in classical wave systems where there is no or weak response to actual magnetic fields. In this work, we construct acoustic PMFs in bilayer phononic crystals by imposing uniaxial linear gradient strain on the scatterers of both layers. Under the PMFs, the linear nodal rings, occurring at around the K and K′ points of the bilayer phononic crystals, split into acoustics Landau levels (LLs). Specifically, the = 0 plateau of the LLs splits into two discrete ones due to the interlayer coupling. Furthermore, we construct two heterostructures by splicing two phononic crystals with opposite PMFs and observe unique in-plane snake-like propagations of the edge state as well as oscillations between the upper and lower layers. Bilayer structure provides additional degree of freedom to generate PMFs in various types of semimetals and enriches the manipulation of acoustic wave propagations. In addition, it can be extended to other classical wave systems, such as electromagnetic wave and mechanical systems.
24
Liang, Jing Cheng, Lei Zhang, Zhangjie Luo, Rui Zhe Jiang, Zhang Wen Cheng, Si Ran Wang, Meng Ke Sun, Shi Jin, Qiang Cheng, and Tie Jun Cui. "A filtering reconfigurable intelligent surface for interference-free wireless communications." Nature Communications 15, no. 1 (May 7, 2024). http://dx.doi.org/10.1038/s41467-024-47865-6.
Анотація:
AbstractThe powerful capability of reconfigurable intelligent surfaces (RISs) in tailoring electromagnetic waves and fields has put them under the spotlight in wireless communications. However, the current designs are criticized due to their poor frequency selectivity, which hinders their applications in real-world scenarios where the spectrum is becoming increasingly congested. Here we propose a filtering RIS to feature sharp frequency-selecting and 2-bit phase-shifting properties. It permits the signals in a narrow bandwidth to transmit but rejects the out-of-band ones; meanwhile, the phase of the transmitted signals can be digitally controlled, enabling flexible manipulations of signal propagations. A prototype is designed, fabricated, and measured, and its high quality factor and phase-shifting characteristics are validated by scattering parameters and beam-steering phenomena. Further, we conduct a wireless communication experiment to illustrate the intriguing functions of the RIS. The filtering behavior enables the RIS to perform wireless signal manipulations with anti-interference ability, thus showing big potential to advance the development of next-generation wireless communications.
25
Zhang, Chao, Anzhong Wang, and Tao Zhu. "Universal horizons and black hole spectroscopy in gravitational theories with broken Lorentz symmetry." European Physical Journal C 83, no. 9 (September 22, 2023). http://dx.doi.org/10.1140/epjc/s10052-023-11998-7.
Анотація:
AbstractThe violation of Lorentz invariance (LI) in gravitational theories, which allows superluminal propagations, dramatically alters the causal structure of the spacetime and modifies the notion of black holes (BHs). Instead of metric horizons, now universal horizons (UHs) define the boundaries of BHs, within which a particle cannot escape to spatial infinities even with an infinitely large speed. Then, a natural question is how the quasi-normal modes (QNMs) of a BH are modified, if one considers the UH as its causal boundary. In this paper, we study in detail this problem in Einstein–Aether theory, a vector-tensor theory that violates LI but yet is self-consistent and satisfies all observations to date. Technically, this poses several challenges, including singularities of the perturbation equations across metric horizons and proper identifications of ingoing modes at UHs. After overcoming these difficulties, we show that the QNMs of the Schwarzschild BH, also a solution of Einstein–Aether theory, consist of two parts, the metric and aether parts. The QNMs of the metric perturbations are quite similar to those obtained in general relativity and are consistent with current observations of gravitational waves. But the ones from aether perturbations are different, and our numerical studies indicate that they are even not stable. The latter is consistent with our previous studies, which showed that the stealth Schwarzschild BH suffers a Laplacian instability along the angular direction. The method and techniques developed in this paper can be applied to the studies of QNMs in other theories of gravity with broken LI.
26
Hwang, Minki, Su-Jin Lee, Chul-Hyun Lim, Eun Bo Shim, and Hyang-Ae Lee. "The three-dimensionality of the hiPSC-CM spheroid contributes to the variability of the field potential." Frontiers in Physiology 14 (March 21, 2023). http://dx.doi.org/10.3389/fphys.2023.1123190.
Анотація:
Background: Field potential (FP) signals from human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) spheroid which are used for drug safety tests in the preclinical stage are different from action potential (AP) signals and require working knowledge of the multi-electrode array (MEA) system. In this study, we developed in silico three-dimensional (3-D) models of hiPSC-CM spheroids for the simulation of field potential measurement. We compared our model simulation results against in vitro experimental data under the effect of drugs E-4031 and nifedipine.Methods:In silico 3-D models of hiPSC-CM spheroids were constructed in spherical and discoidal shapes. Tetrahedral meshes were generated inside the models, and the propagation of the action potential in the model was obtained by numerically solving the monodomain reaction-diffusion equation. An electrical model of electrode was constructed and FPs were calculated using the extracellular potentials from the AP propagations. The effects of drugs were simulated by matching the simulation results with in vitro experimental data.Results: The simulated FPs from the 3-D models of hiPSC-CM spheroids exhibited highly variable shapes depending on the stimulation and measurement locations. The values of the IC50 of E-4031 and nifedipine calculated by matching the simulated FP durations with in vitro experimental data were in line with the experimentally measured ones reported in the literature.Conclusion: The 3-D in silico models of hiPSC-CM spheroids generated highly variable FPs similar to those observed in in vitro experiments. The in silico model has the potential to complement the interpretation of the FP signals obtained from in vitro experiments.
27
Galiana, Joachim, and Benjamin Lasorne. "Excitation energy transfer and vibronic relaxation through light-harvesting dendrimer building blocks: A nonadiabatic perspective." Journal of Chemical Physics 160, no. 10 (March 11, 2024). http://dx.doi.org/10.1063/5.0193264.
Анотація:
The light-harvesting excitonic properties of poly(phenylene ethynylene) (PPE) extended dendrimers (tree-like π-conjugated macromolecules) involve a directional cascade of local excitation energy transfer (EET) processes occurring from the “leaves” (shortest branches) to the “trunk” (longest branch), which can be viewed from a vibronic perspective as a sequence of internal conversions occurring among a connected graph of nonadiabatically coupled locally excited electronic states via conical intersections. The smallest PPE building block that is able to exhibit EET, the asymmetrically meta-substituted PPE oligomer with one acetylenic bond on one side and two parallel ones on the other side (hence, 2-ring and 3-ring para-substituted pseudo-fragments), is a prototype and the focus of the present work. From linear-response time-dependent density functional theory electronic-structure calculations of the molecule as regards its first two nonadiabatically coupled, optically active, singlet excited states, we built a (1 + 2)-state-8-dimensional vibronic-coupling Hamiltonian model for running subsequent multiconfiguration time-dependent Hartree wavepacket relaxations and propagations, yielding both steady-state absorption and emission spectra as well as real-time dynamics. The EET process from the shortest branch to the longest one occurs quite efficiently (about 80% quantum yield) within the first 25 fs after light excitation and is mediated vibrationally through acetylenic and quinoidal bond-stretching modes together with a particular role given to the central-ring anti-quinoidal rock-bending mode. Electronic and vibrational energy relaxations, together with redistributions of quantum populations and coherences, are interpreted herein through the lens of a nonadiabatic perspective, showing some interesting segregation among the foremost photoactive degrees of freedom as regards spectroscopy and reactivity.
28
Chinnaiah, Senthilraja, Saurabh Gautam, Benjamin Herron, Fekede Workneh, Charles M. Rush, and Kiran R. Gadhave. "Novel strains of a pandemic plant virus, tomato spotted wilt orthotospovirus, increase vector fitness and modulate virus transmission in a resistant host." Frontiers in Microbiology 14 (September 29, 2023). http://dx.doi.org/10.3389/fmicb.2023.1257724.
Анотація:
Tomato spotted wilt orthotospovirus (TSWV) is one of the most successful pandemic agricultural pathogens transmitted by several species of thrips in a persistent propagative manner. Current management strategies for TSWV heavily rely on growing single-gene resistant cultivars of tomato (“Sw-5b” gene) and pepper (“Tsw” gene) deployed worldwide. However, the emergence of resistance-breaking strains (RB) in recent years has compounded the threat of TSWV to agricultural production worldwide. Despite this, an extensive study on the thrips transmission biology of RB strains is currently lacking. It is also unclear whether mutualistic TSWV-thrips interactions vary across different novel strains with disparate geographical origins. To address both critical questions, we studied whether and how four novel RB strains of TSWV (two sympatric and two allopatric), along with a non-RB strain, impact western flower thrips (WFT) fitness and whether this leads to differences in TSWV incidence, symptom severity (virulence), and virus accumulation in two differentially resistant tomato cultivars. Our findings show that all RB strains increased WFT fitness by prolonging the adult period and increasing fecundity compared to non-RB and non-viruliferous controls, regardless of the geographical origin of strains or the TSWV titers in individual thrips, which were substantially low in allopatric strains. TSWV accumulation in thrips varied at different developmental stages and was unrelated to the infected tissues from which thrips acquired the virus. However, it was significantly positively correlated to that in WFT-inoculated susceptible plants, but not the resistant ones. The TSW incidences were high in tomato plants infected with all RB strains, ranging from 80% to 90% and 100% in resistant and susceptible plants, respectively. However, TSW incidence in the non-RB-infected susceptible tomato plants was 80%. Our findings provide new insights into how novel strains of TSWV, by selectively offering substantial fitness benefits to vectors, modulate transmission and gain a potential epidemiological advantage over non-RB strains. This study presents the first direct evidence of how vector-imposed selection pressure, besides the one imposed by resistant cultivars, may contribute to the worldwide emergence of RB strains.