905 research outputs found

    On differences between fractional and integer order differential equations for dynamical games

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    We argue that fractional order (FO) differential equations are more suitable to model complex adaptive systems (CAS). Hence they are applied in replicator equations for non-cooperative game. Rock-Scissors-Paper game is discussed. It is known that its integer order model does not have a stable equilibrium. Its fractional order model is shown to have a locally asymptotically stable internal solution. A FO asymmetric game is shown to have a locally asymptotically stable internal solution. This is not the case for its integer order counterpart.Comment: 4 page

    How to Capture Reciprocal Communication Dynamics: Comparing Longitudinal Statistical Approaches in Order to Analyze Within- and Between-Person Effects

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    Choosing an appropriate statistical model to analyze reciprocal relations between individuals’ attitudes, beliefs, or behaviors over time can be challenging. Often, decisions for or against specific models are rather implicit and it remains unclear whether the statistical approach fits the theory of interest. For longitudinal models, this is problematic since within- and between-person processes can be confounded leading to wrong conclusions. Taking the perspective of the reinforcing spirals model (RSM) focusing on media effects and selection, we compare six statistical models that were recently used to analyze the RSM and show their ability to separate within- and between-person components. Using empirical data capturing respondents’ development during adolescence, we show that results vary across statistical models. Further, Monte Carlo simulations indicate that some approaches might lead to wrong conclusions if specific communication dynamics are present. In sum, we recommend using approaches that explicitly model and clearly separate within- and between-person effects

    Nile perch fish nuggets: Partial replacement of fish flesh with sesame hulls and sunroot — Quality assessment and storage stability

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    This study aimed to produce Nile perch fish nuggets by replacing a part of fish flesh with different concentrations of sesame hulls and sunroot to reach the optimal recipe. Chemical, microbiological, and sensory characteristics of nuggets were evaluated during 3 months of frozen storage at –18 °C. According to the obtained data on the chemical composition of raw materials, Nile perch flesh had the highest content of protein (20.21%), sesame hulls contained the highest amount of fat (13.54%), fiber (17.24%) and ash (16.11%), while sunroot tubers had the highest amount of carbohydrates (15.76%). Based on the sensory score, the acceptable replacement ratio for fish nuggets prepared with sunroot (T1) and sesame hulls (T2) was 10% and 7.5%, respectively. Thiobarbituric acid (TBA) analysis at zero time shows that the T1 samples had the minimum value compared to the T2 and control samples. During storage, the TBA levels increased slightly in all samples, but after three months T1 also showed the lowest value. The total plate count (TPC) and psychrophilic bacterial (PSY) count in the samples were affected by the period of frozen storage at –18 °C. The initial TPC and PSY loads were 2.32 and 2.02 log cfu/g for control; 2.24 and 1.72 log cfu/g for T1; 2.30 and 1.47 log cfu/g for T2, respectively. During storage, the values of TPC and Psy slightly decreased. In conclusion, this study succeeded in the replacement of Nile perch fish with sesame hulls and sunroot as new sources to improve the nutritional value and quality characteristics of fish nuggets.This study aimed to produce Nile perch fish nuggets by replacing a part of fish flesh with different concentrations of sesame hulls and sunroot to reach the optimal recipe. Chemical, microbiological, and sensory characteristics of nuggets were evaluated during 3 months of frozen storage at –18 °C. According to the obtained data on the chemical composition of raw materials, Nile perch flesh had the highest content of protein (20.21%), sesame hulls contained the highest amount of fat (13.54%), fiber (17.24%) and ash (16.11%), while sunroot tubers had the highest amount of carbohydrates (15.76%). Based on the sensory score, the acceptable replacement ratio for fish nuggets prepared with sunroot (T1) and sesame hulls (T2) was 10% and 7.5%, respectively. Thiobarbituric acid (TBA) analysis at zero time shows that the T1 samples had the minimum value compared to the T2 and control samples. During storage, the TBA levels increased slightly in all samples, but after three months T1 also showed the lowest value. The total plate count (TPC) and psychrophilic bacterial (PSY) count in the samples were affected by the period of frozen storage at –18 °C. The initial TPC and PSY loads were 2.32 and 2.02 log cfu/g for control; 2.24 and 1.72 log cfu/g for T1; 2.30 and 1.47 log cfu/g for T2, respectively. During storage, the values of TPC and Psy slightly decreased. In conclusion, this study succeeded in the replacement of Nile perch fish with sesame hulls and sunroot as new sources to improve the nutritional value and quality characteristics of fish nuggets

    Piezoelastic PVDF/TPU nanofibrous composite membrane: Fabrication and characterization

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    Poly (vinylidene fluoride) nanofibers (PVDF NFs) have been extensively used in energy harvesting applications due to their promising piezoresponse characteristics. However, the mechanical properties of the generated fibers are still lacking. Therefore, we are presenting in this work a promising improvement in the elasticity properties of PVDF nanofibrous membrane through thermoplastic polyurethane (TPU) additives. Morphological, physical, and mechanical analyses were performed for membranes developed from different blend ratios. Then, the impact of added weight ratio of TPU on the piezoelectric response of the formed nanofibrous composite membranes was studied. The piezoelectric characteristics were studied through impulse loading testing where the electric voltage had been detected under applied mass weights. Piezoelectric characteristics were investigated further through a pressure mode test the developed nanofibrous composite membranes were found to be mechanically deformed under applied electric potential. This work introduces promising high elastic piezoelectric materials that can be used in a wide variety of applications including energy harvesting, wearable electronics, self-cleaning filters, and motion/vibration sensors. - 2019 by the authors.The project was funded “partially” by Kuwait Foundation for the Advancement of Sciences under project code: PN17-35EE-02

    Outbreaks of myxomatosis in Egyptian domestic rabbit farms

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    [EN] Myxomatosis is an endemic infectious, severe and often fatal disease of rabbit caused by myxoma virus. In the present study, myxomatosis outbreaks were reported in 7 domestic rabbit farms in Egypt. Rabbits showed oedema of the eyelids, facial oedema and blepharoconjunctivitis. The morbidity and lethality rates were 18-100% and 20-80%, respectively. The myxomatosis diagnosis was based on histopathology, virus isolation on rabbit kidney cell line (RK-13), polymerase chain reaction (PCR) and sequence analysis. Histopathological examination revealed the presence of epidermal hyperplasia, dermal necrosis and intracytoplasmic eosinophilic inclusion bodies. The virus was isolated on RK-13 cells and induced cytopathic effect. Using PCR, a band of 471 base pair corresponding to the M071L gene was amplified from extracted DNA. Sequence alignment of four out of the 7 isolates revealed that these isolates were 98-99% identical to European and Australian rabbit myxoma reference viruses. In conclusion, rabbit myxomatosis outbreaks and virus isolation procedures are reported herein for the first time in Egypt. Preventive policies against disease circulation should be adopted by the national authorities.Salem, HM.; Morsy, EA.; Hassanen, EI.; Shehata, AA. (2019). Outbreaks of myxomatosis in Egyptian domestic rabbit farms. World Rabbit Science. 27(2):85-91. https://doi.org/10.4995/wrs.2019.10585SWORD8591272Bertagnoli S., Marchandeau S. 2015. Myxomatosis. Rev. Sci. Tech., 34:549-556. https://doi.org/10.20506/rst.34.2.2378Best S.M., Collins S.V., Kerr P.J. 2000. Coevolution of host and virus: cellular localization of virus in myxoma virus infection of resistant and susceptible European rabbits. Virology, 277: 76-91. https://doi.org/10.1006/viro.2000.0505Brugman V.A., Hernández-Triana L.M., Prosser S.W., Weland.C., Westcott D.G., Fooks A.R., Johnson N. 2015. Molecular species identification, host preference and detection of myxoma virus in the Anopheles maculipennis complex (Diptera: Culicidae ) in southern England, UK. Parasit Vectors., 8: 421. https://doi.org/10.1186/s13071-015-1034-8Calvete C., Estrada R., Lucientes J., Osacar J., Villafuerte R. 2004. Effects of vaccination against viral haemorrhagic disease (VHD) and myxomatosis on long-term mortality rates of European wild rabbits. Vet. Rec., 155: 388-392. https://doi.org/10.1136/vr.155.13.388Cameron C., Hota-Mitchell S., Chen L., Barrett J., Cao J.X., Macaulay C., Willer D., Evans D., McFadden G. 1999. The complete DNA sequence of myxoma virus. Virology, 264: 298-318. https://doi.org/10.1006/viro.1999.0001Dalton K.P., Nicieza I., de Llano D., Gullón J., Inza M., Petralanda M., Arroita Z., Parra F. 2015. Vaccine breaks: Outbreaks of myxomatosis on Spanish commercial rabbit farms. Vet. Microbiol. 178: 208-216. https://doi.org/10.1016/j.vetmic.2015.05.008Fenner F. 2000. Adventures with poxviruses of vertebrates. FEMS Microbiol. Rev., 24:123-133.https://doi.org/10.1111/j.1574-6976.2000.tb00536.xFerreira, C., Ramírez, E., Castro, F., Ferreras, P., Alves, P.C., Redpath, S., Villafuerte, R. 2009. Field experimental vaccination campaigns against myxomatosis and their effectiveness in the wild. Vaccine, 27: 6998-7002.https://doi.org/10.1016/j.vaccine.2009.09.075Grodhaus G., Regnery D.C., Marshall I.D. 1963. Studies in the epidemiology of myxomatosis in California. II. The experimental transmission of myxomatosis between brush rabbits (Sylvilagus bachmani ) by several species of mosquitoes. Am. J. Hyg., 77: 205-212. https://doi.org/10.1093/oxfordjournals.aje.a120311Kerr P., McFadden G. 2002. Immune responses to myxoma virus. Viral Immunol., 15: 229-246. https://doi.org/10.1089/08828240260066198Kerr P.J. 2012. Myxomatosis in Australia and Europe: a model for emerging infectious diseases. Antiviral Res., 93: 387-415. https://doi.org/10.1016/j.antiviral.2012.01.009Moss B. 2001. Poxviridae: The viruses and their replication. In: Fields B.N., Howley M.D., Griffin Ph.D., Lamb Ph.D., Martin M.D., Roizman B., Strauss M.D., Knipe Ph. D. (Eds.), Fields' virology, 4th ed., Lippincott Williams & Wilkins, Philadelphia. PA, USA. pp. 2849-2883.OIE. 2107. Manual of Diagnostic tests and vaccines for terrestrial animals. Chapter 2.6.1. Myxomatosis(NB: Version adopted in May 2014).Silvers L., Inglis B., Labudovic A., Janssens P.A., van Leeuwen B.H., Kerr P.J. 2006. Virulence and pathogenesis of the MSW and MSD strains of Californian myxoma virus in European rabbits with genetic resistance to myxomatosis compared to rabbits with no genetic resistance. Virology, 348: 72-83. https://doi.org/10.1016/j.virol.2005.12.007Willer D.O., McFadden G., Evans D.H. 1999. The complete genome sequence of Shope (rabbit) fibroma virus. Virology, 264: 319-343. https://doi.org/10.1006/viro.1999.000

    التركيب المحصولى المصرى فى ظل المخاطرة والمتغيرات المحلية والدولية

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    Cropping pattern refers to the percentage of acreage occupied by various crops within the crop rotation. It is determined through cultivated' area assigned to each crop according to the sequence system necessitated by crop rotation considerations. The optimum crop pattern is the one, which achieves the highest possible net return depending on input and output prices together with crop yields. It is a dynamic process as it changes from time to another based on farmers' needs and crops profitability in the previous year. It also may differ based on whether we are looking from the point of view individual farmer, trader, middleman, and exporter or from the point of view the society as a whole. Various crops are competing on the limited land within the agricultural season. So expanding the acreage of any crop would automatically entail contraction of another competitive crop, as total supply of land is almost fixed and limited. The major objective behind designing an indicative cropping pattern is the issue of food security. This issue is important both from strategic perspective, as well as in the context of poverty. While there is emerging consensus on the definition of food security as aiming to assure the country adequate access to food, both internally and externally generated, there is still reference to the need to grow certain strategic crops. Moreover, there is a desire to achieve a measure of stabilization in producer and consumer prices through the development of buffer stocks. There are various options available, each of which has costs and benefits related to them. One option would be a high level of risk aversion, which would entail a cropping pattern that centers on subsistence crops. Another option may pursue efficiency pricing and therefore would result in crops being growing in which the country has a comparative advantage. For example, self-sufficiency for wheat could be enhanced to 75% in an efficient manner. Meanwhile the domestic production of rice and sugar cane may expand to a frontier that misallocates resources of water and land. The agricultural production is very susceptible to risks originated from natural, economic or social fosters that are difficult to predict or control. In Egypt, cropping pattern, is influenced by local economic variables to up prices, i.e., cropped area is determined by farmer response to changes in absolute or relative prices of the preceding season, in addition to profitability of crops of the last season, where farmer can not change supply of labor, the elapse of period of time curding to the nature of the crops being produced. Egypt's cropping pattern is also affected by international variables related to transactions with international markets for food products and to transactions with international markets for food products and to problem related to world production of biological fuel, world financial crisis, world food crisis, and rules imposed by the international trade system. As a result, there is a deficit in the Egyptian balance of trade for food commodities amounting to L.E. 8 milliards on average for the last few years. The upsurge in demand for agricultural crops like wheat, maize, soybeans, vegetable, oils, and sugar crops for the use in producing biological fuel has resulted in a drastic increase in prices of food, during 2005-2007 the average rate of price increase of food commodities has been estimated at 83% which led to a high increase in import bill in developing -and poor countries among them Egypt which is a not food importer. For many reasons developing an increase in domestic agricultural production of strategic food crops, i.e., cereals legumes. Vegetable, oils, and sugar crops, is the best way to confront international variables, Either through vertical or horizontal expansion of those crops in addition to reducing the acreage of high water consuming scraps, which is the objective behind suggesting the cropping pattern in the short and long terms. Each of these objectives is direct by associated with the master end of ensuring food serenity. Indicative cropping pattern during last years varies considerably as compared to the actual cropping pattern experienced by farmers' decisions irrespective of the agricultural policy of the government Egypt. However, indicative or proposed cropping pattern could be put into action by introducing economic, institution and organization instruments. Those various instruments should be streamlined and harmonized together. Economic instruments advisable for execution of cropping pattern could include subsidizing production and inputs for strategic export and import crops that minimize consumption of irrigation water, introducing contractual agricultural production system, especially, in regard to cotton, sugar cane and sugar beet in addition to other industrial crops. It is advisable to establish agricultural stabilization funds to insure' farmers against various types of risks notably price risks. More over incentives either negative like taxes or positive like interest rate reduction, and rescheduling of debts could also be provided and operated. One major organizational instrument that has been successful recently introduced at a probation scale in three governorates is the national project for development of the field irrigation system in wade and delta. It is estimated that application of that project would save 15% of water consumed for irrigation. The saved water could be used for ameliorating and reclaiming an estimated acreage of 3 million feddans. In addition it is suggested that elimination of camels and messages on the fields would save and area of 0.5 million feddans to be put under cultivation. The study has estimated risk associated with Egyptian cropping pattern by application of linear and non-linear mathematical programming. Three models of minimization risk have been proposed and manipulated including: (1) Minimization Of Total Absolute Deviations: (MOTAD). (2) Risk Input-Output MOTAD. (3) Two Stage Stochastic Programming – (TSSP-RIO-MOTAD). In addition to the various scenarios cited above with their respective major objective functions, the models do comprise acreage, means of production in terms of cost of production, monthly year round irrigation water, and annual agricultural labor on monthly basis. Sensitivity analysis has been estimated for depicting the effect of changing prices of wheat and rice on cropping pattern disposition, by the application of TSSP-RIO-MOTAD model. Among the major results of these analyses are: 1- An increment of gross margin to farmers at L.E 3.8 milliard which deeps that suggested cropping has achieved the profit maximization goal which producers would aim at. 2- A huge amount of irrigation water has been saved estimated at 2.6 milliard cubic meters. A magnitude of water saved of this amount could be assigned for reclaiming new lands at about 0.7 million feddans. 3- Capital resources saved estimated at L.E. 985 million. 4- Augmenting acreage under wheat to reach as much as 3 million feddans, which help contributing positives to the nation's food security goal. 5- Reduction in rice acreage so as not to exceed one million feddan. Adding to the nations objectives of saving irrigation water to be used for reclamation of additional new lands. 6- Augmenting acreage cultivated to Soya beans, sunflower, maize, and summer sorghum at 84.9%, 69.5%, 41%, and 12.3% respectively, which, once again, contributes to the nation's objective related to enhancing food security. 7- Augmenting areas under lentil, lupine, chickpeas, broad bean, and fenugreek by 111%, 62.2%, 39.5%, 19.8%, and 8.6% respectively, which positively adds to food security objective. The proposed cropping pattern derived through sensitivity analysis and based on varying farm- prices for wheat and rice is heavily dependent on the effectiveness and synergy of mechanisms and instruments suggested for addressing and implementing of the indicative cropping pattern. Securing the accomplishment of maximization of farmer's profit margin are very major and essential objectives of the proposed cropping pattern
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