Beam self-cleaning in multimode optical fibers and hydrodynamic 2D turbulence

We experimentally demonstrate the conservation of the average mode number in the process of Kerr beam self-cleaning in a graded-index multimode optical fiber, in analogy with wave condensation in hydrodynamic 2D turbulence

Hydrodynamic 2D Turbulence and Spatial Beam Condensation in Multimode Optical Fibers

We show that Kerr beam self-cleaning results from parametric mode mixing instabilities that generate a number of nonlinearly interacting modes with randomized phases - optical wave turbulence, followed by a direct and inverse cascade towards high mode numbers and condensation into the fundamental mode, respectively. This optical self-organization effect is an analogue to wave condensation that is well known in hydrodynamic 2D turbulence

Organization and effectiveness of marketing management of agricultural commodity producers under non-cooperative marketing: the experience of Ukraine

Under reducing domestic demand for food in Ukraine and increasing dependence on the world food market, a significant part of quasi-price rent from its sale is assigned by intermediary exporters, thus reducing the welfare of domestic commodity producers and consumers. To mitigate this negative effect, it is necessary to have a carefully designed marketing business strategy. The purpose of this article is to summarize the practice of using the main elements of the marketing complex, analyze the effective management of marketing activities of agricultural producers in Ukraine and determine the main directions for increasing its effectiveness by establishing marketing relations for the product supply. Given the large area of Ukraine and the complexity to obtain monographic data that are not subject to monitoring by the State Statistics Service, the study was conducted using agricultural enterprises of the typical agricultural district, namely Khrystynivka district of Cherkasy region (Ukraine) as an example. It is revealed that the use of marketing tools by agricultural enterprises is limited due to the specifics of commodity products and the managers’ focus on short-term business goals. The analysis of forming and realizing the marketing complex of the district enterprises using the monographic method has shown that enterprises systematically use only elements such as commodity policy and distribution policy, while relying exclusively on retrospective marketing data. Significant increase in the return on marketing costs in the short term can only be achieved if formal or informal associations of commodity producers are formed on a functional-territorial basis. This will create a scale effect and allow each member to reduce transaction costs and get an additional premium. It is proved that while conducting administrative-territorial reform in Ukraine, it is most appropriate to form such associations within the boundaries of the united territorial communities

Cвязь маркеров повреждения миокарда и показателей кислородного бюджета с параметрами гемодинамики у пациентов с недостаточностью митрального клапана

Цель. Изучение исходного уровня маркеров повреждения миокарда (МПМ), показателей кислородного бюджета и их связи с параметрами гемодинамики у пациентов с недостаточностью митрального клапана (НМК). Материалы и методы. Обследованы 85 пациентов с НМК, которые на момент госпитализации были разделены на две группы с последующим выполнением операции протезирования митрального клапана. Во время госпитализации измеряли уровни МПМ, показатели кислородного бюджета, проводили корреляционный анализ полученных данных и показателей глобальной продольной деформации (ГПД) миокарда, фракции выброса левого желудочка, сердечного индекса. Результаты. В обеих группах обследованных пациентов между показателями натрийуретического пептида и ГПД миокарда выявлена сильная связь, между показателями натрийуретического пептида и фракции выброса левого желудочка - значительная связь. Уровни аланинаминотрансферазы и аспартатаминотрансферазы, креатинфосфатазы и МВ-фракции креатинфосфокиназы тесно коррелировала с величинами ГПД. В то же время связи показателя ГПД с величиной отношения МВ-фракции креатинфосфокиназы к креатинфосфокиназе не обнаружено. Выводы. У пациентов с НМК не наблюдается признаков повреждения миокарда, но чем более выражены нарушения внутрисердечной гемодинамики, тем вероятнее развитие повреждения миокарда при его перегрузке

Mode decomposition method for investigating the nonlinear dynamics of a multimode beam

We overview our recent experimental studies on the nonlinear spatial reshaping of multimode beams at the output of multimode optical fibers. We use a holographic mode decomposition technique, which permits to reveal the variation of the spatial mode composition at the fiber output, as determined by either conservative (the Kerr effect) or dissipative (Raman scattering) nonlinear processes. For the first case, we consider the effect of spatial beam self-cleaning, and we compare experimental mode decompositions with predictions based on the thermodynamic theory, including the case of beams carrying nozero orbital angular momentum. For the second case, we analyze the beam mode content at the output of a Raman laser based on a graded index multimode fiber

Hydrodynamic 2D turbulence and beam self-cleaning in multimode optical fibers

Spatiotemporal light beam dynamics in multimode optical fibers (MMFs) has emerged in recent years as fertile research domain in nonlinear optics. Intriguing spatiotemporal wave propagation phenomena such as multimode optical solitons and parametric instabilities leading to ultra-wideband sideband series, although predicted quite a long time ago, have only been experimentally observed in MMFs in the last few years

Hydrodynamic transverse condensation in multimode optical fibers

Spatiotemporal light beam dynamics in multimode opti- cal fibers (MMFs) has emerged as a fertile domain of scientific research in nonlinear optics and physics]. Intriguing spatiotemporal wave propagation phenomena such as multimode optical solitons, and parametric instabilities leading to ultra-wideband sideband series [3] have only been experimentally observed in MMFs over the last few years. Among these, we are interested to study here the phenomenon of spatial self-condensation or self-cleaning of multimode light beams in MMFs. It is well known that linear beam propagation in MMFs is affected by random mode coupling, which leads to highly irregular speckled intensity patterns at the fiber output, even when the fiber is excited with a high quality, diffraction-limited input beam

Mode decomposition method for investigating the nonlinear dynamics of a multimode beam

We overview our recent experimental studies on the nonlinear spatial reshaping of multimode beams at the output of multimode optical fibers. We use a holographic mode decomposition technique, which permits to reveal the variation of the spatial mode composition at the fiber output, as determined by either conservative (the Kerr effect) or dissipative (Raman scattering) nonlinear processes. For the first case, we consider the effect of spatial beam self-cleaning, and we compare experimental mode decompositions with predictions based on the thermodynamic theory, including the case of beams carrying nozero orbital angular momentum. For the second case, we analyze the beam mode content at the output of a Raman laser based on a graded index multimode fiber