Dynamic Structure Neural Networks for Stable Adaptive Control of Nonlinear Systems

An adaptive control technique, using dynamic structure Gaussian radical basis function neural networks, that grow in time according to the location of the system's state in space is presented for the affine class of nonlinear systems having unknown or partially known dynamics. The method results in a network that is economic in terms of network size, for cases where the state spans only a small subset of state space, by utilising less basis functions than would have been the case if basis functions were centred on discrete locations covering the whole, relevant region of state space. Additionally, the system is augmented with sliding control so as to ensure global stability if and when the state moves outside the region of state-space spanned by the basis functions and to ensure robustness to disturbances that arise due to the network inherent approximation errors and to the fact that for limiting the network size, a minimal number of basis functions are actually being used. Adaptation laws and sliding control gains that ensure system ability in a Lyapunov sense are presented, together with techniques for determining which basis functions are to form part of the network structure. The effectiveness of the method is demonstrated by experiment simulations

Nonlinear Adaptive Control Using Gaussian Networks with Composite Adaptation for Improved Convergence

The use of composite adaptive laws for control of the affine class of nonlinear systems having unknown dynamics is proposed. These dynamics are approximated by Gaussian radial basis function neural network whose parameters are updated by a composite law that is driven by both tracking and estimation errors, combining techniques used in direct and indirect adaptive control. This is motivated by the need to improve the speed of convergence of the unknown parameters, hence resulting in a better system performance. The inherent approximation error of the neural networks might lead to instability because of parameter drift. This is compensated for by augmenting the control law with a low gain sliding mode component and using deadzone adaptation for the indirect part of the composite law, The stability of the system is analysed and the effectiveness of the method is demonstrated by simulation and comparison with a direct adaptive control scheme

Dual and Adaptive Control of Nonlinear Stochastic Systems Using Neural Networks

A suboptimal dual adaptive system is developed for control of stochastic, nonlinear, discrete-time plants that are affine in the control input. The nonlinear functions are assumed to be unknown and neural networks are used to approximate them. Both Gaussian radial basis function and sigmodial multilayer perceptron neural networks are considered and parameter adjustment is based on Kalman filtering techniques. The result is a control law that takes into consideration the uncertainty of the parameter estimates, thereby, eliminating the need of performing prior open-loop plant identification. The performance of the system is analysed by simulation and Monte Carlo analysis and the advantages of the scheme are clearly outlined

Cave morphology and controls on speleogenesis in quartzite: The example of the Itambé do Mato Dentro area in southeastern Brazil

An area of 417 km2 in southeastern Brazil was mapped in detail regarding karst features in quartzite. Landforms typically assigned to carbonate karst terrains are largely absent, except for discrete occurrences of towers and collapse dolines. Caves are the most conspicuous landform, although occurring at a lower density than in most Brazilian carbonate areas. A total of 11 caves were mapped and studied in detail. Caves tend to develop at shallow depths parallel to the slope surface, controlled by lithological facies and the hydraulic gradient. Petrographical analyses suggest that mica (sericite) lenses within the quartzite and both sericite and iron around quartz grains may favour grain disaggregation and later erosional removal in a shallow phreatic environment. Quartzite caves represent a common feature in southeastern Brazil but tend to be isolated features rather than an integrated and areally extensive hydrological system typical of many carbonate settings

Successful Treatment of a Panniculitis-Like Primary Cutaneous T-Cell Lymphoma of the α/β Type with Bexarotene

Subcutaneous panniculitis-like T-cell lymphoma (SPTL) of the α/β type is a rare subtype of non-Hodgkin's lymphoma of the skin. Although these tumors usually run an indolent course, disease-related morbidity is often severe. Clinical findings include subcutaneous tumors located on the extremities or trunk, often accompanied by systemic symptoms like fever or fatigue. Due to the low incidence of SPTL, no standardized therapy has been defined so far and there is currently no curative therapy available for this type of non-Hodgkin's lymphoma. By sharing our experience with bexarotene therapy, we present a safe and potentially improved treatment for patients with SPTL. In the case presented, bexarotene was able to induce remission even after recurrence of disease

Effects of light intensity on the distribution of anthocyanins in Kalanchoe brasiliensis Camb. and Kalanchoe pinnata (Lamk.) Pers

This paper compares two medicinal species of Kalanchoe, which are often used interchangeably by the population, regarding the distribution of anthocyanins under the influence of four luminosity levels for 6 months. For the morphoanatomical analysis, the 6th stem node of each plant was sectioned. Usual histochemical tests revealed the presence of anthocyanins by cross sections of the stems, petioles and leaf blades. The petioles and leaf blades were submitted to the extraction with acidified methanol, and the anthocyanins were quantified by spectrophotometric readings. At the macroscopic level, it was noticed for both species a higher presence of anthocyanins in stems and petioles of plants under full sunlight. The microscopy of K. brasiliensis stems evidenced the deposition of anthocyanins in the subjacent tissue to the epidermis and cortex, which increased with light intensity. In K. pinnata a subepidermal collenchyma was observed, which interfered in the visualization of anthocyanins. In petioles and leaf blades of K. brasiliensis the deposition of anthocyanins was peripheral, and in K. pinnata it was also throughout the cortex. The quantification of anthocyanins in petioles showed in 70% of light higher averages than in 25%, but in leaf blades there were no significant results. This study contributes to the pharmacognosy of Kalanchoe and it is sustained by the description of flavonoids as biological markers of the genus.Este trabalho compara duas espécies medicinais de Kalanchoe utilizadas muitas vezes de forma indiferenciada pela população, quanto à distribuição de antocianinas sob influência de quatro níveis de luminosidade por 6 meses. Para a análise morfoanatômica foi seccionado o 6 º nó do caule de cada planta. Testes histoquímicos clássicos evidenciaram a presença de antocianinas em cortes transversais dos caules, pecíolos e lâminas foliares. Os pecíolos e lâminas foliares foram submetidos à extração com metanol acidificado e as antocianinas foram quantificadas através de leituras espectrofotométricas. Observou-se em nível macroscópico nas duas espécies, maior presença de antocianinas nos caules e pecíolos das plantas sob luz plena. A microscopia de caules de K. brasiliensis evidenciou a deposição de antocianinas no tecido subjacente à epiderme e córtex, o que aumentou com a intensidade luminosa. Em K. pinnata, observou-se colênquima subepidérmico, o que interferiu na visualização de antocianinas. Nos pecíolos e lâminas foliares de K. brasiliensis, a deposição de antocianinas foi periférica e em K. pinnata, se deu também por todo o córtex. A quantificação de antocianinas dos pecíolos mostrou, em 70% de luminosidade, teores superiores aos obtidos em 25%, porém nas lâminas foliares não foram obtidos resultados significativos. Este trabalho contribui para a farmacognosia de Kalanchoe e sustenta-se pela descrição de flavonóides como marcadores biológicos do gênero

Breaking Of Conformal Invariance And Electromagnetic Field Generation In The Universe

It is shown that the breaking of the conformal invariance in quantum electrodynamics due to the trace anomaly results in the generation of long wave electromagnetic fields during inflationary stage of the universe evolution. If the coefficient of the logarithmic charge renormalization is large (due to a large number of charged particles species), these primordial electromagnetic fields can be strong enough to create the observed galactic magnetic fields.Comment: 6 pages, UM - TH - 93 - 0

ПОРУШЕННЯ ВМІСТУ ВІТАМІНІВ ГРУПИ В ПРИ ДИСБІОЗІ КИШЕЧНИКА У ХВОРИХ НА ХРОНІЧНИЙ ПАНКРЕАТИТ ТА ЦУКРОВИЙ ДІАБЕТ 2-ГО ТИПУ

Summary. Intestinal dysbiosis (DB) often occurs in diseases of the digestive tract, in particular in chronic pancreatitis (CP). Clinical manifestation of CP combined with diabetes mellitus (DM) is complicated by indigestion syndrome, hypo- and avitaminosis, dysproteinemia, intoxication. The aim of the study – to determine the features of B vitamins in patients with CP and DM type 2 in the presence of colon dysbiosis (CDB). Material and Methods. 82 patients with CP and DM type 2 were examined. All examined patients underwent general clinical studies, feces for dysbiosis, as well as determining the level of vitamin B1, B6, B9, B12 in the blood serum. Results and Discussion. It was found that 51.2 % of patients with CP and DM have dysbiosis stage III. In patients with CP and DM type 2 were found a decrease the level of vitamin B9, B12 by 3.9-2.8 times and vitamin B6, B1 by 2.6 – 2.0 times (p<0.01) compared with the control group. A strong direct relationship was found between the CDB stage III and the levels of all B vitamins, examined by us. Thus, with the progression of the severity of CDB in patients with CP and DM type 2, determined a decrease of the level of B vitamins with minimal deviation from the control group in CDB of stage I and maximum deviations – in CDB stage III. Conclusions. All patients with CP and DM type 2 were diagnosed a CDB, and more often it was stage III and II (51.2 % and 31.7 % of those examined, respectively). In patients with CP and DM type 2 were found a decrease in the levels of vitamins B1, B6, B9, B12, which directly depend on the severity of CDB in these patients.РЕЗЮМЕ. Дисбиоз кишечника часто возникает при заболеваниях пищеварительного тракта, в частности при хроническом панкреатите. Клиника ХП с сопутствующим ДК осложняется синдромом нарушения пищеварения, гипо- и авитаминозом, диспротеинемией, интоксикацией. Цель исследования – определить особенности обеспечения витаминами группы В больных ХП и сахарным диабетом (СД) 2-го типа при наличии дисбиоза толстой кишки (ТК). Материал и методы. Обследовано 82 больных ХП и СД 2-го типа. Всем обследованным пациентам проведены общеклинические исследования, анализ кала на дисбиоз, а также определение уровня витаминов В1, В6, В9, В12 в сыворотке крови. Результаты. Установлено, что 51,2 % больных ХП и СД 2-го типа имеют дисбиоз IIІ степени. У больных ХП и СД 2-го типа выявлено снижение уровня витаминов В9, В12 в 3,9–2,8 раза и витаминов В6, В1 в 2,6–2,0 раза (р<0,01), по сравнению с показателем контрольной группы. Установлено сильную прямую зависимость между III ст. дисбиоза ТК и уровнями всех обследованных нами витаминов группы В. При прогрессировании выраженности дисбиоза ТК у больных ХП и СД 2-го типа установлено снижение уровня витаминов группы В с минимальным отклонением от показателей контрольной группы при дисбиозе ТК I ст. и максимальным отклонением – при дисбиозе ТК III ст. Выводы. У всех больных ХП и СД 2-го типа установлен дисбиоз ТК, причем, чаще это дисбиоз III и II степеней (у 51,2 % и 31,7 % обследованных соответственно). У больных ХП и СД 2-го типа выявлено снижение уровней витаминов В1, В6, В9, В12, которое прямо зависит от выраженности дисбиоза ТК у данных пациентов.РЕЗЮМЕ. Дисбіоз кишечника часто виникає при захворюваннях травного тракту, зокрема при хронічному панкреатиті. Клініка ХП із супутнім ДК ускладнюється синдромом порушення травлення, гіпо- й авітамінозом, диспротеїнемією, інтоксикацією. Мета – визначити особливості забезпечення вітамінами групи В хворих на ХП та цукровий діабет (ЦД) 2-го типу за наявності дисбіозу товстої кишки (ТК). Матеріал і методи. Обстежено 82 хворих на ХП та ЦД 2-го типу. Усім обстеженим пацієнтам проведено загальноклінічні дослідження, аналіз калу на дисбіоз, а також визначення рівнів вітамінів В1, В6, В9, В12 у сироватці крові. Результати. Встановлено, що 51,2 % хворих на ХП та ЦД 2-го типу мають дисбіоз IIІ ступеня. У хворих на ХП та ЦД 2-го типу виявлено зменшення рівня вітамінів В9, В12 у 3,9–2,8 раза та вітамінів В6, В1 у 2,6–2,0 рази (р<0,01), порівняно з показником контрольної групи. Встановлено сильну пряму залежність між ІІІ ступенем дисбіозу ТК та рівнями всіх вивчених нами вітамінів групи В. Отже, із прогресуванням вираженості дисбіозу ТК у хворих на ХП та ЦД 2-го типу встановлено зменшення рівня вітамінів групи В із мінімальним відхиленням від показників контрольної групи при дисбіозі ТК І ст. та максимальними відхиленнями – при дисбіозі ТК ІІІ ст. Висновки. У всіх хворих на ХП та ЦД 2-го типу встановлено дисбіоз ТК, причому частіше це дисбіоз ІІІ та ІІ ступенів (у 51,2 % та у 31,7 % обстежених відповідно). У хворих на ХП та ЦД 2-го типу виявлено зниження рівнів вітамінів В1, В6, В9, В12, що прямо залежать від вираженості дисбіозу ТК у даних пацієнтів

Explicitly symmetrical treatment of three-body phase space

We derive expressions for three-body phase space that are explicitly symmetrical in the masses of the three particles. We study geometrical properties of the variables involved in elliptic integrals and demonstrate that it is convenient to use the Jacobian zeta function to express the results in four and six dimensions.Comment: 20 pages, latex, 2 postscript figure