832,049 research outputs found

    The solution of the Sixth Hilbert Problem: the Ultimate Galilean Revolution

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    I argue for a full mathematisation of the physical theory, including its axioms, which must contain no physical primitives. In provocative words: "physics from no physics". Although this may seem an oxymoron, it is the royal road to keep complete logical coherence, hence falsifiability of the theory. For such a purely mathematical theory the physical connotation must pertain only the interpretation of the mathematics, ranging from the axioms to the final theorems. On the contrary, the postulates of the two current major physical theories either don't have physical interpretation (as for von Neumann's axioms for quantum theory), or contain physical primitives as "clock", "rigid rod ", "force", "inertial mass" (as for special relativity and mechanics). A purely mathematical theory as proposed here, though with limited (but relentlessly growing) domain of applicability, will have the eternal validity of mathematical truth. It will be a theory on which natural sciences can firmly rely. Such kind of theory is what I consider to be the solution of the Sixth Hilbert's Problem. I argue that a prototype example of such a mathematical theory is provided by the novel algorithmic paradigm for physics, as in the recent information-theoretical derivation of quantum theory and free quantum field theory.Comment: Opinion paper. Special issue of Philosophical Transaction A, devoted to the VI Hilbert problem, after the Workshop "Hilbert's Sixth Problem", University of Leicester, May 02-04 201

    A memetic ant colony optimization algorithm for the dynamic travelling salesman problem

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    Copyright @ Springer-Verlag 2010.Ant colony optimization (ACO) has been successfully applied for combinatorial optimization problems, e.g., the travelling salesman problem (TSP), under stationary environments. In this paper, we consider the dynamic TSP (DTSP), where cities are replaced by new ones during the execution of the algorithm. Under such environments, traditional ACO algorithms face a serious challenge: once they converge, they cannot adapt efficiently to environmental changes. To improve the performance of ACO on the DTSP, we investigate a hybridized ACO with local search (LS), called Memetic ACO (M-ACO) algorithm, which is based on the population-based ACO (P-ACO) framework and an adaptive inver-over operator, to solve the DTSP. Moreover, to address premature convergence, we introduce random immigrants to the population of M-ACO when identical ants are stored. The simulation experiments on a series of dynamic environments generated from a set of benchmark TSP instances show that LS is beneficial for ACO algorithms when applied on the DTSP, since it achieves better performance than other traditional ACO and P-ACO algorithms.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant EP/E060722/01 and Grant EP/E060722/02

    Giant molecular cloud scaling relations: The role of the cloud definition

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    We investigate the physical properties of molecular clouds in disc galaxies with different morphologies: a galaxy without prominent structure, a spiral barred galaxy and a galaxy with flocculent structure. Our N-body/hydrodynamical simulations take into account nonequilibrium H2 and CO chemical kinetics, self-gravity, star formation and feedback processes. For the simulated galaxies, the scaling relations of giant molecular clouds, or so-called Larson's relations, are studied for two types of cloud definition (or extraction method): the first is based on total column density position-position (PP) data sets and the second is indicated by the CO (1-0) line emission used in position-position-velocity (PPV) data. We find that the cloud populations obtained using both cloud extraction methods generally have similar physical parameters, except that for the CO data the mass spectrum of clouds has a tail with low-mass objects M∼103-104 M⊙. Owing toa varying column density threshold, the power-law indices in the scaling relations are significantly changed. In contrast, the relations are invariant to the CO brightness temperature threshold. Finally, we find that the mass spectra of clouds for PPV data are almost insensitive to the galactic morphology, whereas the spectra for PP data demonstrate significant variation. © 2015 The Authors.Bauman Moscow State Technical University, Bauman MSTURussian Science Foundation, RSF: 14-22-00041Russian Foundation for Basic Research, RFBR: MK-4536.2015.2, 15-32-21062, 14-02-00604, 15-02-06204Russian Academy of Sciences, RASMinistero dellâ Istruzione, dellâ Università e della Ricerca, MIUR14-50-00043Ministry of Education and Science of the Russian Federation, Minobrnauka: 3.1781.2014/K, 15-52-45114, 15-02-08293, 2663We thank our referee, Erik Rosolwski, kindly for thoughtful suggestions that greatly improved the quality of the article. We also thank Marco Lombardi for several stimulating discussions and for reading the early versions of the manuscript. The numerical simulations have been performed at the Research Computing Center (Moscow State University) under a Russian Science Foundation grant (14-22-00041) and Joint Supercomputer Center (Russian Academy of Sciences). This work was supported by RFBR grants (14-02-00604, 15-02-06204, 15-32-21062) and by a President of the RF grant (MK-4536.2015.2). SAK has been supported by a postdoctoral fellowship sponsored by the Italian MIUR. AMS has been supported by the Ministry of Education and Science of the Russian Federation within the framework of the research activities (project no. 3.1781.2014/K). This work was also supported by Act 211 Government of the Russian Federation, contract no 02.A03.21.0006. EOV is thankful to the Ministry of Education and Science of the Russian Federation (project 2663) and RFBR (projects 15-02-08293 and 15-52-45114). The thermochemical part was developed under support from the Russian Scientific Foundation (grant 14-50-00043)

    2015-02 Library Impact Statement for BCH/MIC 421 Physical Chemistry for the Life Sciences

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    Library Impact Statement submitted in response to new course proposal for BCH/MIC 421 Physical Chemistry for the Life Sciences. This class was supported with no need for additional resources. Responding library faculty: Michael Cerbo. Requesting faculty: Lenore M. Martin

    Organic farm incomes in England and Wales 2002/03

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    Results from research work carried out for the Department of Environment, Food and Rural Affairs (DEFRA) by the Organic Research Group at the Institute of Rural Sciences, UWA on the economic performance of organic farms in 2002/03 are presented in this report. This report is the second from the OF0189 series of three economic reports on organic farm incomes from 2001/02 through to 2003/04. A fundamental aim of this work is to assess the financial performance of organic farms differentiated by farm type, in order to inform DEFRA policy-making with respect to economics of organic farming, and to provide a basis for assessments by farmers, advisers and other interested parties of the farm-level implications of conversion to and continued organic farming. This research area builds on previous economics work on organic farming carried out by Institute of Rural Sciences, UWA (Project OF0190, covering 1995/962 to 1998/99). Here, time series data is shown using an identical farm analysis technique for the 2001/02 and 2002/03 financial years covering the economic performance of seven organic farm types including cropping, horticulture, lowland and LFA dairy, lowland and LFA cattle and sheep and mixed farming systems. The identical farm samples comprise farms that are present in both 2001/02 and 2002/03. The total number of organic farms for 2002/03, also referred to as the full farm sample data, is shown alongside the identical datasets for 2002/03. Summarised and detailed financial input, output, income, returns to labour and capital, liabilities and assets and some physical performance measures are presented based on current Farm Business Survey data collection and collation guidelines. The full samples of organic farms per robust farm type are sufficiently large to give some reasonable level of confidence in the data; however, it should be noted that the organic farm samples are not statistically representative of their type, although they can be seen as a reasonable indication of farm income levels between organic and conventional data. Smaller identical farm samples should be treated more cautiously as there is a possibility for outliers (especially larger farms) to have some influence on the average results. An additional element of this work is the inclusion of comparable conventional farm data for the farm types shown. Each organic farm within this study was matched with an appropriate cluster of conventional farms based on the resource endowment identifiers/variables of individual organic farms. Broadly speaking, the identifiers/variables included farm type, FBS region, LFA status, utilisable agricultural area, milk quota holding (where applicable) and farm business size. The cluster farm data was averaged for each farm type to derive the comparable conventional farm (CCF) data based on the organic farms from the identical and full farm samples. Overall, the identical sample of organic farms showed a similar or higher level of net farm income for all farm types in 2002/03 than in 2001/02 with the exception of the identical sample of cropping farms, which decreased. On comparing the organic data with the comparable conventional data, the greatest differences in performance were seen in the lowland dairy and lowland cattle and sheep farm types where organic farms performed significantly better in 2002/03. Horticultural and LFA cattle and sheep farm types performed similarly to the comparable conventional farm samples. The organic mixed identical farm sample achieved lower net farm incomes than the conventional farm sample, but the full sample of mixed organic farms in 2002/03 showed a higher net farm income than the conventional farm sample. Gross margin data is presented for organic dairy herds on a herd size and top five performing herd basis. Cattle and sheep gross margins are shown for lowland and LFA farm types in addition to breeding pig and layer gross margins. Crops shown include winter and spring wheat, spring barley, spring and winter oats, triticale, beans, ware potatoes, sugar beet and leek crops. Where applicable, 2001/02 gross margin data is shown alongside the 2002/03 data. Benchmarking data is shown for milk, beef and lamb production enterprises

    A hybrid genetic algorithm and tabu search approach for post enrolment course timetabling

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    Copyright @ Springer Science + Business Media. All rights reserved.The post enrolment course timetabling problem (PECTP) is one type of university course timetabling problems, in which a set of events has to be scheduled in time slots and located in suitable rooms according to the student enrolment data. The PECTP is an NP-hard combinatorial optimisation problem and hence is very difficult to solve to optimality. This paper proposes a hybrid approach to solve the PECTP in two phases. In the first phase, a guided search genetic algorithm is applied to solve the PECTP. This guided search genetic algorithm, integrates a guided search strategy and some local search techniques, where the guided search strategy uses a data structure that stores useful information extracted from previous good individuals to guide the generation of offspring into the population and the local search techniques are used to improve the quality of individuals. In the second phase, a tabu search heuristic is further used on the best solution obtained by the first phase to improve the optimality of the solution if possible. The proposed hybrid approach is tested on a set of benchmark PECTPs taken from the international timetabling competition in comparison with a set of state-of-the-art methods from the literature. The experimental results show that the proposed hybrid approach is able to produce promising results for the test PECTPs.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant EP/E060722/01 and Grant EP/E060722/02

    A memetic particle swarm optimisation algorithm for dynamic multi-modal optimisation problems

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    Copyright @ 2011 Taylor & Francis.Many real-world optimisation problems are both dynamic and multi-modal, which require an optimisation algorithm not only to find as many optima under a specific environment as possible, but also to track their moving trajectory over dynamic environments. To address this requirement, this article investigates a memetic computing approach based on particle swarm optimisation for dynamic multi-modal optimisation problems (DMMOPs). Within the framework of the proposed algorithm, a new speciation method is employed to locate and track multiple peaks and an adaptive local search method is also hybridised to accelerate the exploitation of species generated by the speciation method. In addition, a memory-based re-initialisation scheme is introduced into the proposed algorithm in order to further enhance its performance in dynamic multi-modal environments. Based on the moving peaks benchmark problems, experiments are carried out to investigate the performance of the proposed algorithm in comparison with several state-of-the-art algorithms taken from the literature. The experimental results show the efficiency of the proposed algorithm for DMMOPs.This work was supported by the Key Program of National Natural Science Foundation (NNSF) of China under Grant no. 70931001, the Funds for Creative Research Groups of China under Grant no. 71021061, the National Natural Science Foundation (NNSF) of China under Grant 71001018, Grant no. 61004121 and Grant no. 70801012 and the Fundamental Research Funds for the Central Universities Grant no. N090404020, the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant no. EP/E060722/01 and Grant EP/E060722/02, and the Hong Kong Polytechnic University under Grant G-YH60

    Self-Care Level in Diabetic Patients

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    Objective The present study was done with the objective of assessing the self-care practices among diagnosed type 2 diabetes mellitus patients in hospital of Islamic Azad University of Medical Sciences in Tehran, Iran. Methods In this cross-sectional study, 314 Iranian patients older than 18 years of age with type 2 diabetes were completed Diabetes Self-Management Questionnaire. Data was analyzed by ANOVA, t-test, correlation and liner regression. Results A significant association was found between the diabetes self-management sum scale and body mass index, Dietary control subscale and body mass index, Physical activity subscale and body mass index & job and Healthcare use subscale and diabetes treatment (p<0.05). Conclusion Due to the high BMI in respondents, Overweight and obese respondents need to be advised by health professionals on physical activities and proper diet to achieve healthy weights to avoid complications related to diabetes mellitus. Keywords Diabetes self-management, Type 2 diabetes, Diabetes Self-Management Questionnaire DOI: 10.7176/JMPB/63-02 Publication date: January 31st 202

    Peningkatan Aktivitas Belajar Peserta Didik Menggunakan Media Puzzle IPS Kelas IV di SD

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    : The title of this research is to increase the activity of social science learning using Puzzles in SD media. This study aims to improve the performance of the researcher as a teacher and describe the increased activity of students learning through the medium of the puzzle in the Social Sciences learning in fourth grade 02 Milas. The research method used is the method deskriftip with a qualitative approach in the form of the action research classs (PTK). Research subject is 26 fourth grade students. The results of the study after the analysis was experiencing increasing learners' learning activities. Physical activity initially in the first cycle in the second cycle becomes 53.34 86.54, 47 mental activity, 25di cycle II became 93.95, 52.88 emotional activity in the second cycle becomes 98.01

    Synthesis, Spectroscopic Characterization and Biological Studies Of 2-{[(2-hydroxy-5-nitrophenyl)methylidene]amino} nicotinic acid and Iron (II) complexes

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    Communication in Physical Sciences 2020, 5(2) 106-116 Authors: I. G. Osigbemhe, M. E. Khan, A. Mutairu and I. F. Esekhaigb Received 02 March 2020/Accepted 20 April 2020 Iron (II) complexes of 2-{[(2-hydroxy-5nitrophenyl) methylidene]amino} nicotinic acid obtained from o-phenylenediamine and 5nitrosalicaldehyde were prepared and characterized using AAS, UV-Visible, IR, 1HNMR, 13CNMR, and GCMS. The synthesized complex was screened against some microbes in order to establish their potentials antimicrobial activity with reference to some known drugs. The results obtained indicated that, the Schiff base exhibited antimicrobial action against all the tested microbes (except Candidas. albicans isolate, which exhibited zero diameter zone of inhibition) including Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumonia, Enterobacter aeruginosa, and Proteus mirabilis.. It was also found that the synthesized Schiff base exhibited two digits purity range, implying that it was relatively stable. The biological activity of the metal complex of the Schiff base was found to be better than that of synthesized Schiff base
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