The Limit Behavior Of The Trajectories of Dissipative Quadratic Stochastic Operators on Finite Dimensional Simplex

The limit behavior of trajectories of dissipative quadratic stochastic operators on a finite-dimensional simplex is fully studied. It is shown that any dissipative quadratic stochastic operator has either unique or infinitely many fixed points. If dissipative quadratic stochastic operator has a unique point, it is proven that the operator is regular at this fixed point. If it has infinitely many fixed points, then it is shown that $\omega-$ limit set of the trajectory is contained in the set of fixed points.Comment: 14 pages, accepted in Difference Eq. App

Predicting scour depth around non-uniformly spaced pile groups

Pile scour may cause instability to the structures they support. Ensuring a safe and economically sound design is essential for the wider community. Although much laboratory research has been carried out on scour at pile groups, there are still significant gaps in prediction formulae. This study has been conducted to develop a formula for scour at pile arrangements of non-uniform spacing. The study was based on a laboratory experiment found in the literature. Previous empirical formulae for uniformly spaced pile groups were first used to gauge an idea of their performance. The formula that predicted the scour depth more accurately was then modified. The approach of Ghaemi et al. (2013) outperformed the other trialled empirical formulas. Using this formula, a correction factor was suggested to increase the prediction accuracy. The gap to diameter ratio was also corrected to include the non-uniformity of spacing in two directions

High-throughput bioaccumulation, biotransformation, and production of silver and selenium nanoparticles using genetically engineered Pichia pastoris

A genetically modified Pichia pastoris strain overexpressing a metal-resistant variant of cytochrome b5 reductase enzyme was developed for silver and selenium biosorption and for nanoparticle production. The maximum recombinant enzyme expression level was approximately 31 IU/ml in the intercellular fluid after 24 h of incubation, and the capacity of the recombinant biomass for the biosorption of silver and selenium in aqueous batch models were measured as 163.90 and 63.71 mg/g, respectively. The ions were reduced in the presence of enzyme, leading to the formation of stable 70–180 nm metal nanoparticles. Various instrumental analyses confirmed the well-dispersed and crystalline nature of the spherical nanometals. The purified silver and selenium nanoparticles exhibited at least 10-fold less cytotoxicity toward HDF, EPG85–257, and T47D cells than silver nitrate and selenium dioxide. These results revealed that the engineered Pichia strain is an eco-friendly, rapid, high-throughput, and versatile reduction system for nanometal production

Brane f(R)f(\cal R) gravity

We consider a brane world scenario in which the bulk action is assumed to have the form of a generic function of the Ricci scalar $f(\mathcal{R})$ and derive the resulting Einstein field equations on the brane. In a constant curvature bulk a conserved geometric quantity appears in the field equations which can be associated with matter. We present cosmological and spherically symmetric solutions by assuming specific forms for $f(\mathcal{R})$ and show that the former can explain an accelerated expanding universe while the latter may account for galaxy rotation curves.Comment: 8 pages, 2 figures, to appear in EP

Spatial changes of beach profiles for a small tidal inlet (Currumbin Creek, Australia)

Many tidal inlets are actively monitored to investigate the change in flood or ebb shoals, as these sand deposits can have a major influence on the sediment budget of the adjacent coast. However, here it is hypothesized that the shores of the back barrier area can also act as a source of sediment to be considered in the sediment budget. Therefore, profile changes around Currumbin Creek tidal inlet were considered to identify the extent of such a contribution on the surrounding beach and the overall evolution of the inlet system. The results of 16 weeks survey showed that in general, the shores of the back barrier lagoon had a very marginal effect in the provision of material to the sand budget, although the gorge area is highly vulnerable and dynamic. Even an intense storm event and heavy rainfall during the data collection period, resulting in erosion of the surrounding beaches, showed no significant influence on the shore face of the lagoon

Stemming text-based web page classification using machine learning algorithms: a comparison

The research aim is to determine the effect of word-stemming in web pages classification using different machine learning classifiers, namely Naive Bayes (NB), k-Nearest Neighbour (k-NN), Support Vector Machine (SVM) and Multilayer Perceptron (MP). Each classifiers' performance is evaluated in term of accuracy and processing time. This research uses BBC dataset that has five predefined categories. The result demonstrates that classifiers' performance is better without word stemming, whereby all classifiers show higher classification accuracy, with the highest accuracy produced by NB and SVM at 97% for F1 score, while NB takes shorter training time than SVM. With word stemming, the effect on training and classification time is negligible, except on Multilayer Perceptron in which word stemming has effectively reduced the training time

Antinociceptive Effects of an Extract of Securigera securidaca and their Mechanisms in Mice

We examined the effects of an aqueous extract from seeds of Securigera securidaca L. (S. s.), a plant used in folk medicine, on experimentally induced pain in balb-c mice. The tailflick test (somatic pain evoked by thermonociceptive stimulation) and writhing test (visceral pain after i.p. injections of acetic acid) were used. Three doses of the extract (85, 170, 340 mg of dry substance per 1 kg body mass) were i.p. injected before the tests. Significant antinociception effects were observed in both tests; a dose of 170 mg/kg appeared to be optimum. Antinociceptive effects of the S. s. extract were comparable with those of 1 mg/kg morphine. Naloxone, metoclopramide, ondancetron, and scopolamine (antagonists of opioid, dopamine, serotonin, and cholinergic receptors, respectively) completely eliminated antinociceptive effects of the S. s. extract in the tail-flick test; the effects of these antagonists were not so clear in the writhing test. The mechanisms of analgesic actions of the S. s. extract are discussed; the respective effects are probably related (at least partly) to the presence of flavonoids in this extract. Further investigations are necessary for adequate interpretation of the above mechanisms.Ми досліджували впливи водного екстракту з насіння Securigera securidaca L. (S. s.) – рослини, що використовується в народній медицині, – на експериментально викликаний біль у мишей лінії balb c. Застосовували тест з відсмикуванням хвоста (соматичний біль, викликаний термоноцицептивною стимуляцією) та «корчовий» тест (вісцеральний біль після внутрішньоочеревинних уведень оцтової кислоти). Перед тестами внутрішньоочеревинно ін’єкували екстракт у трьох дозах (85, 170 та 340 мг сухої речовини на 1 кг маси тіла). В обох тестах спостерігали істотні антиноцицептивні впливи екстракту; доза 170 мг/кг виглядала оптимальною. Антиноцицептивні впливи екстракту S. s. були порівняльними з такими після введень 1 мг/кг морфіну. Налоксон, метоклопрамід, ондацетрон та скополамін (антагоністи опіоїдних, дофамінових, серотонінових та холінергічних рецепторів відповідно) повністю нівелювали антиноцицептивні ефекти екстракту S. s. у тесті відсмикування хвоста; ефекти згаданих антагоністів у „корчовому” тесті не були такими очевидними. Обговорюються можливі механізми аналгетичних впливів екстракту S. s.; відповідні ефекти вірогідно залежать (у всякому разі частково) від наявності в цьому екстракті флавоноїдів. Для адекватної інтерпретації зазначених механізмів потрібні подальші дослідження