The Detection of a 3.5-h Period in the Classical Nova Velorum 1999 (V382 Vel) and the Long Term Behavior of the Nova Light Curve

We present CCD photometry, light curve and time series analysis of the classical nova V382 Vel (N Vel 1999). The source was observed for 2 nights in 2000, 21 nights in 2001 and 7 nights in 2002 using clear filters. We report the detection of a distinct period in the light curve of the nova P=0.146126(18) d (3.5 h). The period is evident in all data sets, and we interpret it as the binary period of the system. We also measured an increase in the amplitude modulation of the optical light (in magnitude) by more than 55% from 2000 to 2001 and about 64% from 2001 to 2002. The pulse profiles in 2001 show deviations from a pure sinusoidal shape which progressively become more sinusoidal by 2002. The main cause of the variations in 2001 and 2002 can be explained with the occultation of the accretion disk by the secondary star. We interpret the observed deviations from a pure sinusoidal shape as additional flux resulting from the aspect variations of the irradiated face of the secondary star.Comment: 16 pages and 4 figures, accepted as it stands to be published in the Astronomical Journal (AJ

Multi Agent Diagnosis: an analysis

The paper analyzes the use of a Multi Agent System for Model Based Diagnosis. In a large dynamical system, it is often infeasible or even impossible to maintain a model of the whole system. Instead, several incomplete models of the system have to be used to detect possible faults. These models may also be physically be distributed. A Multi Agent System of diagnostic agents may offer solutions for establishing a global diagnosis. If we use a separate agent for each incomplete model of the system, establishing a global diagnosis becomes a problem cooperation and negotiation between the diagnostic agents. This raises the question whether `a set of diagnostic agents, each having an incomplete model of the system, can (efficiently) determine the same global diagnosis as an ideal single diagnostic agent having the combined knowledge of the diagnostic agents?''economics of technology ;

Some Simple Thoughts on Model Building for Developing Countries

The revival of interest in using models for developing countries for planning and policy advice makes it desirable to draw lessons from past experience. Simple models, focussed on specific issues, are to be preferred to large and comprehensive models. More empirical research is needed on supply and production functions for developing countries. Not statistical criteria but developmental considerations must determine the conclusions to be drawn from models. More explicit explanations of assumptions and modesty in presenting results of modelling work to policy makers are desirable

Wess-Zumino-Witten model off criticality

We study the renormalization group flow properties of the Wess-Zumino-Witten model in the region of couplings between $g^2=0$ and $g^2=4\pi/k$, by evaluating the two-loop Zamolodchikov's $c$-function. We also discuss the region of negative couplings.Comment: 8 page

Large-scale bottleneck effect in two-dimensional turbulence

The bottleneck phenomenon in three-dimensional turbulence is generally associated with the dissipation range of the energy spectrum. In the present work, it is shown by using a two-point closure theory, that in two-dimensional turbulence it is possible to observe a bottleneck at the large scales, due to the effect of friction on the inverse energy cascade. This large-scale bottleneck is directly related to the process of energy condensation, the pile-up of energy at wavenumbers corresponding to the domain size. The link between the use of friction and the creation of space-filling structures is discussed and it is concluded that the careless use of hypofriction might reduce the inertial range of the energy spectrum

Articulating the composite city: the case of Hong Kong

Symposium Theme: Composite CitiesHong Kong, with its dense verticality, public-private function mixes, and cultural mix of East and West, has long been the world model of hybrid metropolitan development. But how is this hybrid condition currently working out? In Hybrid Hong Kong Stephen Yiu-wai Chu argues that the efforts to brand Hong Kong as ‘Asia’s world city’ have led to the loss of Hong Kong’s unique hybridity, which is being replaced by a Central Business District identity in which there is little or no place for vernacular and creative cultures. This paper explores how urban planners in Hong Kong are fighting this tendency, which can also be recognized in other world capitals, using a unique hybrid model which exemplifies top-down bureaucracy meeting bottom-up initiatives to create an urban transaction between government interventions and urban entrepreneurship to foster a composite city. © EURAU2014published_or_final_versio