Continuous data assimilation for the three-dimensional Brinkman-Forchheimer-extended Darcy model

In this paper we introduce and analyze an algorithm for continuous data assimilation for a three-dimensional Brinkman-Forchheimer-extended Darcy (3D BFeD) model of porous media. This model is believed to be accurate when the flow velocity is too large for Darcy's law to be valid, and additionally the porosity is not too small. The algorithm is inspired by ideas developed for designing finite-parameters feedback control for dissipative systems. It aims to obtaining improved estimates of the state of the physical system by incorporating deterministic or noisy measurements and observations. Specifically, the algorithm involves a feedback control that nudges the large scales of the approximate solution toward those of the reference solution associated with the spatial measurements. In the first part of the paper, we present few results of existence and uniqueness of weak and strong solutions of the 3D BFeD system. The second part is devoted to the setting and convergence analysis of the data assimilation algorithm

A Continuous-Time Mathematical Model and Discrete Approximations for the Aggregation of \u3cem\u3eβ\u3c/em\u3e-Amyloid

Alzheimer\u27s disease is a degenerative disorder characterized by the loss of synapses and neurons from the brain, as well as the accumulation of amyloid-based neuritic plaques. While it remains a matter of contention whether β-amyloid causes the neurodegeneration, β-amyloid aggregation is associated with the disease progression. Therefore, gaining a clearer understanding of this aggregation may help to better understand the disease. We develop a continuous-time model for β-amyloid aggregation using concepts from chemical kinetics and population dynamics. We show the model conserves mass and establish conditions for the existence and stability of equilibria. We also develop two discrete-time approximations to the model that are dynamically consistent. We show numerically that the continuous-time model produces sigmoidal growth, while the discrete-time approximations may exhibit oscillatory dynamics. Finally, sensitivity analysis reveals that aggregate concentration is most sensitive to parameters involved in monomer production and nucleation, suggesting the need for good estimates of such parameters

Turmeric (Curcuma longa Linn.) as a phytogenic growth promoter alternative for antibiotic and comparable to mannan oligosaccharides for broiler chicks

This work aimed at investigating the potential as a growth enhancer of different dietary concentrations of turmeric (Curcuma longa Linn.) as an alternative to oxytetracyline and antibiotics and as comparable to mannan oligosaccharide for broiler chicks. A total of 252 Hubbard broiler chicks at one day of age were distributed randomly in a straight run experimental design among six treatments, each replicated seven times, with six unsexed chicks per replicate. The basal diet was administered without supplements (control group) or supplemented with turmeric at 0.5, 1, and 2 g/kg diet, or with mannan oligosacride (MOS) at 1 g/kg feed or with oxytetracycline (OTC) at 50 mg/kg feed. Growth performance, carcass characteristics, meat quality traits, blood biochemical constituents, antioxidant status and red blood cell (RBCs) were investigated. Turmeric supplementation at 1 g/kg feed significantly improved feed conversion ratio (FCR) and European production index compared to the control group and MOS groups. The results indicated that turmeric can be used at 1 kg/t feed as a phytogenic feed additive as an alternative to OTC or MOS without negative effects on the productive and economic traits of broilers. There were no differences from using OTC and MOS, while there was an increase in the European production efficiency index and the broilers’ health status.This work aimed at investigating the potential as a growth enhancer of different dietary concentrations of turmeric (Curcuma longa Linn.) as an alternative to oxytetracyline and antibiotics and as comparable to mannan oligosaccharide for broiler chicks. A total of 252 Hubbard broiler chicks at one day of age were distributed randomly in a straight run experimental design among six treatments, each replicated seven times, with six unsexed chicks per replicate. The basal diet was administered without supplements (control group) or supplemented with turmeric at 0.5, 1, and 2 g/kg diet, or with mannan oligosacride (MOS) at 1 g/kg feed or with oxytetracycline (OTC) at 50 mg/kg feed. Growth performance, carcass characteristics, meat quality traits, blood biochemical constituents, antioxidant status and red blood cell (RBCs) were investigated. Turmeric supplementation at 1 g/kg feed significantly improved feed conversion ratio (FCR) and European production index compared to the control group and MOS groups. The results indicated that turmeric can be used at 1 kg/t feed as a phytogenic feed additive as an alternative to OTC or MOS without negative effects on the productive and economic traits of broilers. There were no differences from using OTC and MOS, while there was an increase in the European production efficiency index and the broilers’ health status

Happiness is assortative in online social networks

Social networks tend to disproportionally favor connections between individuals with either similar or dissimilar characteristics. This propensity, referred to as assortative mixing or homophily, is expressed as the correlation between attribute values of nearest neighbour vertices in a graph. Recent results indicate that beyond demographic features such as age, sex and race, even psychological states such as "loneliness" can be assortative in a social network. In spite of the increasing societal importance of online social networks it is unknown whether assortative mixing of psychological states takes place in situations where social ties are mediated solely by online networking services in the absence of physical contact. Here, we show that general happiness or Subjective Well-Being (SWB) of Twitter users, as measured from a 6 month record of their individual tweets, is indeed assortative across the Twitter social network. To our knowledge this is the first result that shows assortative mixing in online networks at the level of SWB. Our results imply that online social networks may be equally subject to the social mechanisms that cause assortative mixing in real social networks and that such assortative mixing takes place at the level of SWB. Given the increasing prevalence of online social networks, their propensity to connect users with similar levels of SWB may be an important instrument in better understanding how both positive and negative sentiments spread through online social ties. Future research may focus on how event-specific mood states can propagate and influence user behavior in "real life".Comment: 17 pages, 9 figure

Response of Silybum marianum plant to irrigation intervals combined with fertilization

Hendawy SF, Hussein MS, Youssef AA, El-Mergawi RA. 2013. Response of Silybum marianum plant to irrigation intervals combined with fertilization. Nusantara Bioscience 5: 21-28. This study was investigated to evaluate the influence of different kinds of organic and bio fertilization under different irrigation intervals on the growth, production and chemical constituents of Sylibium marianum plant. Data indicated that all studied growth and yield characters were significantly affected by the duration of irrigation intervals. Fertilizer treatments had a primitive effect on growth and yield characters. The interaction between irrigation intervals and fertilizer treatments has a clear considerable effect on growth and yield characters. The obtained results indicated the favorable effect of organic and bio fertilizers which reduce the harmful effect of water stress. Different treatments had a pronounced effect on silymarin content

Cross-Cultural Adaptations of the MacArthur Competence Assessment Tool for Treatment in Iran

Background: According to general ethical and legal principles, valid consent must be obtained before starting any procedure. Objectives: Due to the lack of a standard tool for assessing patients’ capacity to consent to medical treatment in Iran, the present study was carried out aiming to devise a Persian version of a cross-cultural adaptation of the MacArthur competence assessment tool. Patients and Methods: By reviewing different methods of cultural translation and adaptation for assessment tools, and due to the lack of consensus on its processes, we selected Wild’s model as one of the most comprehensive methods in this regard. Wild’s (2005) 10-stage model includes preparation, forward translation, reconciliation of the forward translation, back translation of reconciliation, back translation review, cognitive debriefing and cognitive review, and finalization, proofreading and final reporting. Using this model, we translated the MacArthur assessment tool and made it adaptable to Iranian patients. Results: The MacArthur assessment tool is not dependent on any specific culture and language. As a result, if translation and its scientific adaptation are done based on an integrated and detailed model, the tool can be used for every culture and language. In other words, this tool is not culture-specific; so, it is applicable in cases where a translation is needed, and it can be culturally adapted to suit different societies. Conclusions: In the present study, we are able to focus on and prove the efficacy and benefits of this measurement tool

Optimal design of multi-channel microreactor for uniform residence time distribution

Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimizing the design of the collecting and distributing channels which supply the series of rectangular microchannels of the reactor, in the case of liquid flows. The accuracy of this analytical approach is discussed after comparison with CFD simulations and hybrid analytical-CFD calculations that allow an improved refinement of the meshing in the most complex zones of the flow. The analytical model is then extended to the case of microchannels with other cross-sections (trapezoidal or circular segment) and to gaseous flows, in the continuum and slip flow regimes. In the latter case, the model is based on second-order slip flow boundary conditions, and takes into account the compressibility as well as the rarefaction of the gas flow

A Comparative Study of the Effect of Some Mineral and Plant Oils on the Two Spotted Spider Mite Tetranychus urticae Koch (Acari: Tetranychidae)

The direct toxicity of some mineral and plant oils to the eggs and females of the two spotted spider mite Tetranychus urticae Koch was tested. KZ oil was toxic to the egg stage compared to adult female. In contrast, Natur'l oil has a close toxic effect for both stages of T. urticae. Bio-dux oil was proved to be toxic to adult female and relatively in toxic to egg stage. Females of T. urticae suffered a depression in reproduction and shortened longevity when kept on plant leaves previously treated with different oils. Laboratory studies indicated that the vegetable oil Natur'l oil was effective on all biological aspects of T. urticae studied

Seminavis aegyptiaca sp. Nov., a new amphoroid diatom species from estuary epilithon of the river–nile damietta branch, Egypt

During a recent floristic–taxonomic study on the algal flora, including diatoms, from the estuary of the Damietta Branch of the Nile in Egypt, an interesting epilithic diatom species belonging to the genus Seminavis (Naviculaceae) was collected and investigated using both light and scanning electron microscopy. This new diatom species shares morphologically some taxonomic diagnostic features with other related taxa such as S. insignis, S. robusta, and S. ventricosa. However, it still differs by having ventral central striae that are shorter and more or less straight in the middle of the smaller frustules to be clearly radiate in the larger ones and then become geniculate and only radiate near the poles, the central raphe endings are externally more distantly spaced than in the similar species, the elongate central nodule is internally less prominent, and the areola density is much denser. Therefore, we here describe it as Seminavis aegyptiaca sp. nov. Hydrochemical analyses revealed that S. aegyptiaca commonly inhabits typical marine, with a weak tendency towards brackish water, habitats. It was found to be tolerant to meso–eutrophic, nutrient–enriched conditions, based on the data available on seasonal concentrations of N and P compounds. These findings not only contribute to the inventory of Egyptian diatoms, but also increase our understanding of the autecology and distribution of this relatively poorly–known diatom genus