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11.
We develop the superfield background field method and study the effective action in the N = 2, d3 supersymmetric Chern-Simons-matter systems. The one-loop low-energy effective action for non-Abelian supersymmetric Chern-Simons theory is computed to order F 4 by use of N = 2 superfield heat kernel techniques. 相似文献
12.
EI Rodriguez Martinez CI Barriga-Paulino MI Zapata CC Chinchilla AM López-Jiménez CM Gómez 《BMC neuroscience》2012,13(1):104-23
ABSTRACT: BACKGROUND: The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). RESULTS: The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0--20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. CONCLUSIONS: The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages. 相似文献
13.
EISSA Abd EI-Monem Mohamed Farag 《中国化学》2008,26(8):1509-1514
A variety of pyrimidine derivatives 2—4 and annulated pyrimidine derivatives 5—17 have been synthesized via a sequence of heterocyclization reaction of readily available 6-naphthyl-4-oxo-2-thioxo-1,2,3,4-tetrahydroprimi- 相似文献
14.
Tamer Shoeib Junfang Zhao Houssain EI Aribi Alan C. Hopkinson K. W. Michael Siu 《Journal of the American Society for Mass Spectrometry》2013,24(1):38-48
The fragmentations of [AA + M]+ complexes, where AA = Phe, Tyr, Trp, or His, and M is a monovalent metal (Li, Na, or Ag), have been exhaustively studied through collision-induced dissociation (CID) and through deuterium labeling. Dissociations of the Li- and Ag-containing complexes gave a large number of fragment ions; by contrast, the sodium/amino acid complexes have lower binding energies, and dissociation resulted in much simpler spectra, with loss of the entire ligand dominating. Unambiguous assignments of these fragment ions were made and formation mechanisms are proposed. Of particular interest are fragmentations in which the charge was retained on the organic fragment and the metal was lost, either as a metal hydride (AgH) or hydroxide (LiOH) or as the silver atom (Ag?). Caption for Graphical Abstract
CID products of Li+, Na+, and Ag+ complexes of Phe, Tyr, Trp, and His are reported and mechanisms by which they are formed are proposed. 相似文献
15.
A convenient synthesis of intermediate 4,5‐diamino‐3‐aryl‐1‐phenylpyrazoles 4a – 4c was reported. The different cyclization reactions were carried out with chalcone, 2‐mercaptoacetic acid and p‐anisialdehyde, ethyl chloroformate, glyoxal and thiourea to afford different N and S containing heterocycles. The reaction conditions were compared by conventional heating and microwave irradiation. The structures of the cyclization products were determined by analytical and spectroscopic data. All the synthesized compounds were screened for antibacterial activities in vitro. 相似文献
16.
A complete set of solutions of the Dirac equation is found in space-time with the metric ds2 = 2(d
2- dx2- dy2- dz2). For the Green's functions
in$$
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and
in$$
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, representations are found in the form of contour integrals from the Schwinger-De Witt nucleus over various contours.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 35–40, April, 1985.It remains to thank Yu. Yu. Vol'fengaut for discussions in the course of the present work. 相似文献
17.
G. A. Vershinin V. A. Volkov G. L. Buchbinder G. I. Gering 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2014,8(4):712-716
The nonisothermal mass transfer in metal materials under irradiation with concentrated energy fluxes is studied in the one-dimensional approximation. Local nonequilibrium equations of extended irreversible thermodynamics are used to describe the transfer phenomena. It is established that, for short times (on the order of the time required for relaxation of the diffusion flow to its local-equilibrium value), the wave mechanism for mass transfer is dominant over the diffusion one, ensuring that the impurity-concentration profiles have a nonmonotonous form. The degree of influence of the space-time nonlocality of the transfer processes on the formation of concentration profiles is estimated, and the model results are compared with the experimental data. 相似文献
18.
Orly Buchbinder 《International Journal of Mathematical Education in Science & Technology》2018,49(1):138-153
The nine-point circle theorem is one of the most beautiful and surprising theorems in Euclidean geometry. It establishes an existence of a circle passing through nine points, all of which are related to a single triangle. This paper describes a set of instructional activities that can help students discover the nine-point circle theorem through investigation in a dynamic geometry environment, and consequently prove it using a method of guided discovery. The paper concludes with a variety of suggestions for the ways in which the whole set of activities can be implemented in geometry classrooms. 相似文献
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20.
In this paper, we analyze the role of examples in the proving process. The context chosen for this study was finding a general rule for triangular numbers. The aim of this paper is to show that examples are effective for the construction of a proof when they allow cognitive unity and structural continuity between argumentation and proof. Continuity in the structure is possible if the inductive argumentation is based on process pattern generalization (PPG), but this is not the case if a generalization is made on the results. Moreover, the PPG favors the development of generic examples that support cognitive unity and structural continuity between the argumentation and proof. The cognitive analysis presented in this paper is performed through Toulmin??s model. 相似文献