Computing isogenies between Jacobian of curves of genus 2 and 3

We present a quasi-linear algorithm to compute isogenies between Jacobians of curves of genus 2 and 3 starting from the equation of the curve and a maximal isotropic subgroup of the l-torsion, for l an odd prime number, generalizing the V\'elu's formula of genus 1. This work is based from the paper "Computing functions on Jacobians and their quotients" of Jean-Marc Couveignes and Tony Ezome. We improve their genus 2 case algorithm, generalize it for genus 3 hyperelliptic curves and introduce a way to deal with the genus 3 non-hyperelliptic case, using algebraic theta functions.Comment: 34 page

MANAGERIAL Culture – “Mental EquipmenT” at the Employees Disposal in the Tourism Units

Environmental adaptation and behavioral integration are two major problems the organization of this beginning of century is confronting with. Organizational culture is one of the solutions to solving these problems. This paper presents the characteristics of organizational culture and the degree of influence on it by the different levels of managers. The most important part of the paper presents how managers can change the culture of organizations through influencing the cultural web of it.managerial culture, tourism organizations

The Tourism industry of Ethics and tourism

The tourism industry is one of the largest industries in the world, and despite recent events that have made its operating environment more complex, the industry continues to grow [Theobald, 2005, Global Tourism, 3rdedn., Butterworth-Heinemann/Elsevier]. Commensurate to the size of the industry is a growth in the number of students pursuing degree courses in tourism around the world. Despite an increasingly sophisticated literature, the relative recency of the industry and its study has meant little attention has been paid in the ethics literature to the dilemmas facing tourism managers and its students. Based on interviews with senior members of the tourism industry six scenarios are developed with pertinence to the challenges faced by industry practitioners today.ethics in tourism, ethical decision-manking

The Role of Regional Development Policies in Reducing Territorial Disparities

This paper aim is to analyze the variance of the net nominal monthly earnings by counties and development regions using the most recent estimated statistics from Statistical yearbook 2007. We applied one-factor analysis of variance – ANOVA. We considered that the „Romanian development regions” is a factor of interest and we tested if it has a significant effect on the “net nominal monthly earnings” regional differences.economic development; social development; competitiveness; growth; regional development.

Apparent versus true value of the cosmological constant

Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the universe can be accurately described by a homogeneous model. Even in the presence of a cosmological constant we cannot exclude nevertheless the presence of a small local inhomogeneity which could affect the apparent value of the cosmological constant. Neglecting the presence of the inhomogeneity can in fact introduce a systematic misinterpretation of cosmological data, leading to the distinction between an apparent and the true value of the cosmological constant. But is such a difference distinguishable? Recently we set out to model the local inhomogeneity with a {\Lambda}LTB solution and computed the relation between the apparent and the true value of the cosmological constant. In this essay we reproduce the essence of our model with the emphasis on its physical implications.Comment: Some parts need to be revise