371 research outputs found
Genus one factors of curves defined by separated variable polynomials
We give some sufficient conditions on complex polynomials P and Q to assure
that the algebraic plane curve P(x)-Q(y)=0 has no irreducible component of
genus 0 or 1. Moreover, if deg (P)=deg (Q) and if both P, Q satisfy Hypothesis
I introduced by H. Fujimoto, our sufficient conditions are necessary
Spectral properties of the surface reflectance of the northern polar region of Mercury
We analyse MESSENGER reflectance measurements covering the northern polar
region of Mercury, the least studied region of the northern mercurian
hemisphere. We use observations from the Mercury Dual Imaging System Wide-Angle
Camera (MDIS/WAC) and the Mercury Atmospheric and Surface Composition
Spectrometer (MASCS/VIRS) to study the spectral dependence of the surface
reflectance. The results obtained from the observations made by both
instruments are remarkably consistent. We find that a second degree polynomial
description of the measured reflectance spectra gives very good fits to the
data and that the information that they carry can best be characterized by two
parameters, the mean reflectance and the mean relative spectral slope, averaged
over the explored range of wavelengths. The properties of the four main types
of terrains known to form Mercury's regolith in the northern region, smooth
plains (SP), heavily cratered terrain (HCT), fresh ejecta/materials and red
pitted ground (RPG) are examined in terms of these two parameters. The results
are compared, and found consistent with those obtained by earlier studies in
spite of difficulties met in obtaining accurate reflectance measurements under
the large incidence angle condition characteristic of polar regions. These
results will help with the preparation of the BepiColombo mission and with
supporting its observational strategy.Comment: 21 pages, 15 figures, accepted for publication in Research in
Astronomy and Astrophysic
Le projet d'avenir, le virtuel et l'adolescence au Vietnam : impact du style de conduite par rapport Ă Internet sur la relation entre le mode d'identification et le projet d'avenir
When entering adolescence, a subject must highly mobilize himself to confirm his new identity and become a dynamic and autonomous being, author of his life (Malrieu, 1973). Vietnamese society is currently passing through the cultural encounter between traditional values and modern trends, with the domination of information and communication technologies and the Internet. The adolescents must then experience their crisis period at the same time as contextual conflicts (Nguyen Khac Vien, 1997). The objective of our research is to study how the current generation of Vietnamese adolescents identifies with others and how these modes of identification influence the way they project themselves into the future. Our aim is also to analyze the impact of Internet use, a teenagersâ new practice, on the relationship between their modes of identification and future plans.Using questionnaires and projective tests (the TAT and the Test of Three Characters), we conducted our data collection from 102 Vietnamese adolescents (53 girls and 49 boys) aged 16.5 to 18 and regularly using the Internet.Our results show that among the adolescents in our sample, some defensive modes of identification are significantly associated with the positive aspects of their future plans as well as with an appropriate style of Internet use. Our results also confirm that the style of Internet use has a mediating effect on the relationship between the mode of identification and future plans; more precisely the positive link between the identification of dependence and the plans of relational and professional achievement is explained by the Internet practices serving school duties and tasks. Supported by theoretical advances in psychology, we analyzed, explained and clarified the salient results of our research in an interpretative way by replacing these results in the current context of Vietnamese society.Lorsquâil entre dans lâadolescence, le sujet doit faire preuve dâune grande mobilisation pour affirmer sa nouvelle identitĂ© et devenir un acteur dynamique et autonome, auteur de son histoire (Malrieu, 1973). La sociĂ©tĂ© vietnamienne est actuellement traversĂ©e par la rencontre culturelle du traditionnel et du moderne, avec la domination des nouvelles technologies et dâInternet. Les adolescents doivent alors vivre leur crise en mĂȘme temps que des conflits contextuels (Nguyen Khac Vien, 1997). Lâobjectif de notre recherche est dâĂ©tudier la façon dont les adolescents vietnamiens de la gĂ©nĂ©ration actuelle sâidentifient aux autres et aux Ă©vĂ©nements sociaux et comment ces formes identificatoires influencent la maniĂšre dont ils se projettent vers lâavenir. Nous cherchons aussi Ă analyser lâimpact de lâusage dâInternet, une nouvelle pratique des jeunes, sur la relation entre ces modes dâidentification et le projet dâavenir de ces derniers.Par le biais de questionnaires et dâĂ©preuves projectives (le TAT et le Test des Trois Personnages), nous avons effectuĂ© notre recueil des donnĂ©es auprĂšs de 102 adolescents vietnamiens (53 filles et 49 garçons) ĂągĂ©s de 16,5 Ă 18 ans et ayant une pratique assidue dâInternet. Nos rĂ©sultats montrent que chez les adolescents de notre Ă©chantillon, certains modes dĂ©fensifs dâidentification sont significativement associĂ©s Ă des dimensions positives de leur projet et Ă un usage appropriĂ© dâInternet. Nos rĂ©sultats confirment Ă©galement que le style de pratique dâInternet a un effet mĂ©diateur sur la relation entre le mode dâidentification et le projet dâavenir, dans la mesure oĂč le lien positif entre lâidentification de dĂ©pendance et les projets dâaccomplissement relationnel et professionnel est modulĂ© par les pratiques dâInternet qui alimentent des devoirs et des tĂąches scolaires. En replaçant les rĂ©sultats saillants de notre recherche dans le contexte actuel de la sociĂ©tĂ© vietnamienne, une analyse interprĂ©tative, Ă©tayĂ©e par des avancĂ©es thĂ©oriques en psychologie, nous permet dâĂ©clairer et dâexpliquer ces rĂ©sultats
Quantum Gauss Jordan Elimination
In this paper we construct the Quantum Gau\ss Jordan Elimination (QGJE)
Algorithm and estimate the complexity time of computation of Reduced Row
Echelon Form (RREF) of an matrix using QGJE procedure. The main
theorem asserts that QGJE has computation time of order
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