1,353 research outputs found
Management Of Fishing Of The Broadband Anchovy (anchoviella Lepidentostole) (fowler, 1911), In South SĂŁo Paulo State, Brazil.
The broadband anchovy (Anchoviella lepidentostole) is one of the most important fishery resources for economic and social development of Iguape City and for the whole of the south coast of SĂŁo Paulo state. Nowadays this activity involves over 2,500 fishermen. This paper aims to evaluate its fishing, and discuss how the activity is managed. In order to conduct this study, production data and catch per unit effort (CPUE) data from the 1998-2000 period have been collected, and the characterisation of the activity has also been done. A decline in broadband anchovy abundance had been observed in the region up until 2004, when a new regulation was implemented, in an attempt to recover the resource, with the establishment of closed season fishing (defeso) during the catch season, and adjustments in the employed fishing gear. The results have shown a recovery of the abundance of broadband anchovy throughout the 2005-2010 period, showing thus far that the measures taken for the maintenance of the resource have been successful. The activity has been managed through discussions involving people from the fishing sector in order to determine the controversial actions to be taken, that are hard to enforce. In order to achieve a more satisfactory resource management, it is necessary to keep the participatory process, with adaptive co-management, based on discussion among all the sectors involved (from government and society), and constant monitoring of the activity.73691-
Nonlinear excitation of zonal flows by rossby wave turbulence
We apply the wave-kinetic approach to study nonlinearly coupled Rossby wave-zonal flow fluid turbulence in a two-dimensional rotating fluid. Specifically, we consider for the first time nonlinear excitations of zonal flows by a broad spectrum of Rossby wave turbulence. Short-wavelength Rossby waves are described here as a fluid of quasi-particles, and are referred to as the 'Rossbyons'. It is shown that Reynolds stresses of Rossbyons can generate large-scale zonal flows. The result should be useful in understanding the origin of large-scale planetary and near-Earth atmospheric circulations. It also provides an example of a turbulent wave background driving a coherent structure
Amplification and generation of ultra-intense twisted laser pulses via stimulated Raman scattering
Twisted Laguerre-Gaussian lasers, with orbital angular momentum and
characterised by doughnut shaped intensity profiles, provide a transformative
set of tools and research directions in a growing range of fields and
applications, from super-resolution microcopy and ultra-fast optical
communications to quantum computing and astrophysics. The impact of twisted
light is widening as recent numerical calculations provided solutions to
long-standing challenges in plasma-based acceleration by allowing for high
gradient positron acceleration. The production of ultrahigh intensity twisted
laser pulses could then also have a broad influence on relativistic
laser-matter interactions. Here we show theoretically and with ab-initio
three-dimensional particle-in-cell simulations, that stimulated Raman
backscattering can generate and amplify twisted lasers to Petawatt intensities
in plasmas. This work may open new research directions in non-linear optics and
high energy density science, compact plasma based accelerators and light
sources.Comment: 18 pages, 4 figures, 1 tabl
Hand Foot and Mouth Disease in Adults - A Case Report
A doença de mĂŁos-pĂ©s-boca Ă© uma infecção viral, mais frequentemente causada pelos vĂrus coxsackie A16 e enterovĂrus 71, que afecta preferencialmente crianças com idade inferior a 10 anos. Geralmente Ă© uma doença benigna, caracterizada por febre e vesĂculas na boca e extremidades distais, mas tambĂ©m pode associar-se a complicaçÔes mais graves com meningoencefalite ou miocardite. Os autores reportam um caso de DMPB num
adulto imunocompetente, com 27 anos de idade, que apresentava påpulas das mãos, pés e cavidade oral, algumas com progressão
posterior para vesĂculas. A exuberĂąncia do quadro clĂnico e curso mais prolongado da doença tambĂ©m constituĂram caracterĂsticas
pouco usuais
Cutaneous Tuberculosis. A Case Report
Apesar de a tuberculose cutĂąnea (TBC) compreender apenas entre 0,1 a 4,4 por cento de todos os casos de tuberculose, Ă© importante para os clĂnicos considerarem esta infecção quando confrontados com uma lesĂŁo
cutĂąnea de etiologia nĂŁo esclarecida. AlĂ©m do M. tuberculosis, tambĂ©m os bacilos M. bovis e Bacillus Calmette-Guerin (BCG) podem causar infecção da pele. A tuberculose cutĂąnea âverdadeiraâ pode ser adquirida por via exĂłgena (quando hĂĄ inoculação directa do bacilo na pele), ou endĂłgena, e apresenta um largo espectro de apresentaçÔes clĂnicas. Reportamos um caso de escrofuloderma (envolvimento da pele por contiguidade
a partir de um outro foco de infecção), com linfadenite tuberculosa e envolvimento
da clavĂcula, numa mulher imunocompetente
Recommended from our members
Super-rotating jets in the atmospheres of terrestrial planets
Super-rotation is a ubiquitous phenomenon in the four substantial atmospheres possessed by solid bodies in the solar system. This paper reviews recent global model results and reanalyses by data assimilation, in particular for Mars and Venus
Amplification and generation of ultra-intense twisted laser pulses via stimulated Raman scattering
Twisted LaguerreâGaussian lasers, with orbital angular momentum and characterized by doughnut-shaped intensity profiles, provide a transformative set of tools and research directions in a growing range of fields and applications, from super-resolution microcopy and ultra-fast optical communications to quantum computing and astrophysics. The impact of twisted light is widening as recent numerical calculations provided solutions to long-standing challenges in plasma-based acceleration by allowing for high-gradient positron acceleration. The production of ultra-high-intensity twisted laser pulses could then also have a broad influence on relativistic laserâmatter interactions. Here we show theoretically and with ab initio three-dimensional particle-in-cell simulations that stimulated Raman backscattering can generate and amplify twisted lasers to petawatt intensities in plasmas. This work may open new research directions in nonlinear optics and highâenergy-density science, compact plasma-based accelerators and light sources
Photon-graviton pair conversion
We consider the conversion of gravitons and photons as a four-wave mixing
process. A nonlinear coupled systems of equations involving two gravitons and
two photons is obtained, and the energy exchange between the different degrees
of freedom is found. The scattering amplitudes are obtained, from which a
crossection for incoherent processes can be found. An analytical example is
given, and applications to the early Universe are discussed.Comment: 5 pages, slightly modified as compared to v1, to appear in Class.
Quantum Grav. as a Letter to the Edito
High orbital angular momentum harmonic generation
We identify and explore a high orbital angular momentum (OAM) harmonics generation and amplification mechanism that manipulates the OAM independently of any other laser property, by preserving the initial laser wavelength, through stimulated Raman backscattering in a plasma. The high OAM harmonics spectra can extend at least up to the limiting value imposed by the paraxial approximation. We show with theory and particle-in-cell simulations that the orders of the OAM harmonics can be tuned according to a selection rule that depends on the initial OAM of the interacting waves. We illustrate the high OAM harmonics generation in a plasma using several examples including the generation of prime OAM harmonics. The process can also be realized in any nonlinear optical Kerr media supporting three-wave interactions
High orbital angular momentum harmonic generation
We identify and explore a high orbital angular momentum (OAM) harmonics generation and amplification mechanism that manipulates the OAM independently of any other laser property, by preserving the initial laser wavelength, through stimulated Raman backscattering in a plasma. The high OAM harmonics spectra can extend at least up to the limiting value imposed by the paraxial approximation. We show with theory and particle-in-cell simulations that the orders of the OAM harmonics can be tuned according to a selection rule that depends on the initial OAM of the interacting waves. We illustrate the high OAM harmonics generation in a plasma using several examples including the generation of prime OAM harmonics. The process can also be realized in any nonlinear optical Kerr media supporting three-wave interactions.info:eu-repo/semantics/publishedVersio
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