Along-stream evolution of Gulf Stream volume transport

Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 50(8), (2020): 2251-2270, doi:10.1175/JPO-D-19-0303.1.The Gulf Stream affects global climate by transporting water and heat poleward. The current’s volume transport increases markedly along the U.S. East Coast. An extensive observing program using autonomous underwater gliders provides finescale, subsurface observations of hydrography and velocity spanning more than 15° of latitude along the path of the Gulf Stream, thereby filling a 1500-km-long gap between long-term transport measurements in the Florida Strait and downstream of Cape Hatteras. Here, the glider-based observations are combined with shipboard measurements along Line W near 68°W to provide a detailed picture of the along-stream transport increase. To account for the influences of Gulf Stream curvature and adjacent circulation (e.g., corotating eddies) on transport estimates, upper- and lower-bound transports are constructed for each cross–Gulf Stream transect. The upper-bound estimate for time-averaged volume transport above 1000 m is 32.9 ± 1.2 Sv (1 Sv ≡ 106 m3 s−1) in the Florida Strait, 57.3 ± 1.9 Sv at Cape Hatteras, and 75.6 ± 4.7 Sv at Line W. Corresponding lower-bound estimates are 32.3 ± 1.1 Sv in the Florida Strait, 54.5 ± 1.7 Sv at Cape Hatteras, and 69.9 ± 4.2 Sv at Line W. Using the temperature and salinity observations from gliders and Line W, waters are divided into seven classes to investigate the properties of waters that are transported by and entrained into the Gulf Stream. Most of the increase in overall Gulf Stream volume transport above 1000 m stems from the entrainment of subthermocline waters, including upper Labrador Sea Water and Eighteen Degree Water.We gratefully acknowledge funding from the Office of Naval Research (N000141713040), the National Science Foundation (OCE-0220769, OCE-1633911, OCE-1923362), NOAA’s Global Ocean Monitoring and Observing Program (NA14OAR4320158, NA19OAR4320074), WHOI’s Oceans and Climate Change Institute, Eastman Chemical Company, and the W. Van Alan Clark, Jr. Chair for Excellence in Oceanography at WHOI (awarded to Breck Owens)

Argumentação multimodal e inferências intersemióticas: um estudo semiolinguístico

The discourse emerges from the multisemiotic complexity that characterizes language and, for this reason, encompasses different dimensions in the investigation of discourses materialized in texts.  In this paper, based on Semiolinguistic Theory of Discourse, proposed by Charaudeau (2008; 2016; 2018), we intend to demonstrate that the argumentative dimension of a discourse can be engendered by the strategic use of different modalities, which we call multimodal argumentation. For this, using notions of internal centripetal inference and external centrifugal inference we analyze three media texts constituted by the compulsory association of word and image, namely: cartoon, comic and advertisement, in addition to discussing the relationship, apparently dissonant, between headline and photograph that figure in two news, subjectivity of the production instance in a predominantly informative genre. The analyses indicated that, through a specific cut of the social space, the subjects involved in the communicative exchanges integrate and correlate the multiple semioses in the processes of production and movements internal and external to the utterance.O discurso emerge da complexidade multissemiótica que caracteriza a linguagem e, por essa razão, engloba diferentes dimensões na investigação de discursos materializados em textos. Neste artigo, à luz dos pressupostos da Teoria Semiolinguística do Discurso, proposta por Patrick Charaudeau (2008; 2016; 2018), procuramos demonstrar que a dimensão argumentativa de um discurso pode ser engendrada pelo emprego estratégico de diferentes modalidades, a que chamamos de argumentação multimodal. Para isso, por meio das noções de inferência centrípeta interna e inferência centrífuga externa, analisamos três textos midiáticos constituídos pela associação compulsória de palavra e imagem, a saber: charge, tira e peça publicitária, além de discutirmos a relação, aparentemente dissonante, entre manchete e fotografia que figuram em duas notícias, revelando a subjetividade avaliativa da instância de produção em um gênero de caráter predominantemente informativo. As análises sinalizaram que, por meio de um recorte específico do espaço social, os sujeitos envolvidos nas trocas comunicativas integram e correlacionam as múltiplas semioses nos processos de produção e compreensão, sob os quais atuam movimentos inferenciais internos e externos ao enunciado

ANÁLISE SEMIOLINGUÍSTICA DO DISCURSO LITERÁRIO: PARTE DA HISTÓRIA DO BRASIL SOB O OLHAR DE UM CRONISTA MINEIRO

O presente artigo procura apresentar uma análise semiolinguística da crônica História do Brasil, de autoria do escritor mineiro Paulo Mendes Campos. A análise foi realizada a partir dos postulados teóricos e metodológicos da Teoria Semiolinguística do Discurso, de Patrick Charaudeau (2012), bem como a partir de determinados conceitos advindos da Gramática Sistêmico-Funcional. Ao longo da análise, demonstramos como o sujeito enunciador empresta sua voz ao Criador, o deus judaico-cristão, em um processo interdiscursivo entre o texto literário, religioso e histórico que narra breve e criticamente a história do Brasil. Nesse processo, diversos sentidos podem ser desvelados do texto que, mesmo produzido há tantas décadas, ainda permanece atual. Sob o prisma da esfera literária, o texto de Paulo Mendes Campos mostra-se atemporal e faz o leitor mergulhar criticamente nos eventos históricos que retratam a alienação do brasileiro desde a colonização

Instabilities of waves in nonlinear disordered media

We develop a self-consistent theory of temporal fluctuations of a speckle pattern resulting from the multiple scattering of a coherent wave in a weakly nonlinear disordered medium. The speckle pattern is shown to become unstable if the nonlinearity exceeds a threshold value. The instability is due to a feedback provided by the multiple scattering and manifests itself in spontaneous fluctuations of the scattered intensity. The development of instability is independent of the sign of nonlinearity.Comment: 6 pages, 2 PostScript figures, accepted to Phys. Rev. Let

Вибір та обґрунтування параметрів технології підтримки стінок стовбура свердловини в осадових породах

Практичне значення роботи полягає в досліджені широкого кола властивостей різних хімічних сполук, покликаних збільшити ступінь стійкості осадових порід в стінках стовбура свердловини; застосування досліджених речовин приведе до істотного підвищення продуктивності бурових робіт, скорочення часу на роботи, пов’язані із ліквідацією ускладнень і аварій в свердловині, або повного виключення останніх, загального зростання ефективності і економічності процесу спорудження свердловин.Мета дипломної роботи: встановлення закономірностей фізико-хімічних процесів, що протікають в стовбурі свердловини, споруджуваної в товщі осадових гірських порід, при циркуляції промивальних рідин і формулюванні на їх основі адекватних технологічних заходів гідравлічної програми промивання свердловини, реалізація якої дозволить надати процесу спорудження свердловин достатньо високу міру продуктивності і економічності

Weak localization of light by cold atoms: the impact of quantum internal structure

Since the work of Anderson on localization, interference effects for the propagation of a wave in the presence of disorder have been extensively studied, as exemplified in coherent backscattering (CBS) of light. In the multiple scattering of light by a disordered sample of thermal atoms, interference effects are usually washed out by the fast atomic motion. This is no longer true for cold atoms where CBS has recently been observed. However, the internal structure of the atoms strongly influences the interference properties. In this paper, we consider light scattering by an atomic dipole transition with arbitrary degeneracy and study its impact on coherent backscattering. We show that the interference contrast is strongly reduced. Assuming a uniform statistical distribution over internal degrees of freedom, we compute analytically the single and double scattering contributions to the intensity in the weak localization regime. The so-called ladder and crossed diagrams are generalized to the case of atoms and permit to calculate enhancement factors and backscattering intensity profiles for polarized light and any closed atomic dipole transition.Comment: 22 pages Revtex, 9 figures, to appear in PR

Autonomous and Lagrangian ocean observations for Atlantic tropical cyclone studies and forecasts

Author Posting. © The Oceanography Society, 2017. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 30, no. 2 (2017): 92–103, doi:10.5670/oceanog.2017.227.The tropical Atlantic basin is one of seven global regions where tropical cyclones (TCs) commonly originate, intensify, and affect highly populated coastal areas. Under appropriate atmospheric conditions, TC intensification can be linked to upper-ocean properties. Errors in Atlantic TC intensification forecasts have not been significantly reduced during the last 25 years. The combined use of in situ and satellite observations, particularly of temperature and salinity ahead of TCs, has the potential to improve the representation of the ocean, more accurately initialize hurricane intensity forecast models, and identify areas where TCs may intensify. However, a sustained in situ ocean observing system in the tropical North Atlantic Ocean and Caribbean Sea dedicated to measuring subsurface temperature, salinity, and density fields in support of TC intensity studies and forecasts has yet to be designed and implemented. Autonomous and Lagrangian platforms and sensors offer cost-effective opportunities to accomplish this objective. Here, we highlight recent efforts to use autonomous platforms and sensors, including surface drifters, profiling floats, underwater gliders, and dropsondes, to better understand air-sea processes during high-wind events, particularly those geared toward improving hurricane intensity forecasts. Real-time data availability is key for assimilation into numerical weather forecast models.The NOAA/AOML component of this work was originally funded by the Disaster Relief Appropriations Act of 2013, also known as the Sandy Supplemental, and is currently funded through NOAA research grant NA14OAR4830103 by AOML and CARICOOS, as well as NOAA’s Integrated Ocean Observing System (IOOS). The TEMPESTS component of this work is supported by NOAA through the Cooperative Institute for the North Atlantic Region (NA13OAR4830233) with additional analysis support from the WHOI Summer Student Fellowship Program, Nortek Student Equipment Grant, and the Rutgers University Teledyne Webb Graduate Student Fellowship Program. The drifter component of this work is funded through NOAA grant NA15OAR4320071(11.432) in support of the Global Drifter Program

Temporal fluctuations of waves in weakly nonlinear disordered media

We consider the multiple scattering of a scalar wave in a disordered medium with a weak nonlinearity of Kerr type. The perturbation theory, developed to calculate the temporal autocorrelation function of scattered wave, fails at short correlation times. A self-consistent calculation shows that for nonlinearities exceeding a certain threshold value, the multiple-scattering speckle pattern becomes unstable and exhibits spontaneous fluctuations even in the absence of scatterer motion. The instability is due to a distributed feedback in the system "coherent wave + nonlinear disordered medium". The feedback is provided by the multiple scattering. The development of instability is independent of the sign of nonlinearity.Comment: RevTeX, 15 pages (including 5 figures), accepted for publication in Phys. Rev.

Antrum Approach Planning for Removal of Impacted Tooth Using Cone-Beam Computed Tomography

Due to the great number of structures in the maxillofacial region, cone-beam computed tomography (CBCT) is an important procedure in presurgical planning for removal of impacted teeth. Most of the information provided by this imaging technique cannot be visualized in conventional radiographs. In addition, CBCT reduces patient exposure to radiation in comparison with helical computed tomography and provides dental practitioners with easy access. We report the clinical case of a patient who underwent a surgical procedure for removal of an impacted maxillary premolar. CBCT-assisted presurgical treatment was used, enabling a more conservative surgical access, a less traumatic and less time consuming procedure than conventional surgical intervention

Wax crystallization from solution in hierarchical morphology templated by random poly(ethylene-co-butene) self-assemblies

Semicrystalline poly(ethylene-butene) (PEB-n) random copolymers can modify the sizes of wax crystals and thus improve the viscoelastic properties of crude oil and middle distillate fuels at low temperatures. The wax-copolymer interactions in solution are rather complex and not fully understood. When the copolymer self-assembles at temperatures higher than the wax cloud point a hierarchy of morphologies templated by the primordial polymer structure evolves with decreasing temperature. Multilevel structures showing characteristic sizes from 10 mu m to 1 nm are formed upon cooling in solutions of semicrystalline PEB-7.5 copolymers and in wax containing mixed solutions. The coplymer structures with the different wax molecules were evaluated by three SANS techniques (conventional SANS, focusing-SANS and ultra-SANS) and contrast matching. Complementary microscopy techniques allowed a direct visualization of these structures in real space