Constraints on time variation of fine structure constant from WMAP-3yr data

This paper presents the constraints on the time variation of the fine structure constant at recombination relative to its present value, Delta_alpha = (alpha_rec-alpha_0) / alpha_0, obtained from the analysis of the WMAP-3yr Cosmic Microwave Background (CMB) data, with an additional prior on the Hubble expansion rate from HST Hubble Key Project. I found out that -0.039 < Delta_alpha < 0.010 at 95% C.L., which brings a 30% improvement to the previous limits from WMAP-1yr data. The corresponding recombination redshift, 1012 < z_rec < 1115, shows a delayed recombination epoch compared with the results from WMAP-1yr data.Comment: 11 pages, 3 figures; accepted for publication in New Astronomy, June 02 200

Thermal analysis applied to estimation of solidification kinetics of Al–Si aluminium alloys

Evaluation of solidification kinetics by thermal analysis is a useful tool for quality control of Al–Si melts before pouring provided it is rapid and highly reproducible. Series of thermal analysis records made with standard cups are presented that show good reproducibility. They are evaluated using a Newton’s like approach to get the instantaneous heat evolution and from it solidification kinetics. An alternative way of calculating the zero line is proposed which is validated by the fact that the latent heat of solidification thus evaluated is within 5% of the value calculated from thermodynamic data. Solidification kinetics was found highly reproducible provided appropriate experimental conditions were achieved: high enough casting temperature for the cup to heat up to the metal temperature well before solidification starts; and equal and homogeneous temperatures of the metal and of the cup at any time in the temperature range used for integration

A.D.XENOPOL, A LESS KNOWN ECONOMIST

Outstanding Romanian man of culture in the second half of the XIXa€™th century, known as remarkable historian, A.D.Xenopol was also a genuine economist, preoccupied not only by the theory but also by the practice of economics. I have achieved an investigA.D.Xenopol, economist, XIXth century, thematic works, of present interest

The Modeling of the Decisional Process A Case of Study for the Portfolio Management

In the architecture of the management functionality and performance, its decisional component has a privileged position. No other element has a more stressed managerial specificity and a greater impact in all the plans of its activities and results. There are the main reasons which determined the authors to do a detailed analyze of the elements which intervene in decisional process. To have as a result a well founded and opportune decision any decisional model had to acquire, process, interpret a larger volume of information, in a shorter period. These demands have directed the whole structure of this paper.decision, decisional model, decisional variables, parameters, cause – effect relations.

The Need of Knowledge Management Strategy for the Successfully Implementation of Reengineering Projects

This paper want to shown that current knowledge management approaches do not emphasise enough on knowledge sharing from reengineering project perspective. To achieve success with reengineering project, an organisation must possess and share knowledge about many different facets of this process. While many reengineering projects have resulted in improve performance, we believe that higher levels of performance improvement are possible by coupling IT capabilities with KM strategy. To explain these results it was assumed that the key to implementing with success reengineering project is having a wide knowledge management strategy. Our objective for the paper reported here was to understand the factors that motivate to share knowledge before implementing any knowledge management strategy to sustain the successfully implementation of reengineering projects.Information Technologies, knowledge, knowledge management, strategy, reengineering, project

Rates of asymptotic regularity for Halpern iterations of nonexpansive mappings

In this paper we obtain new effective results on the Halpern iterations of nonexpansive mappings using methods from mathematical logic or, more specifically, proof-theoretic techniques. We give effective rates of asymptotic regularity for the Halpern iterations of nonexpansive self-mappings of nonempty convex sets in normed spaces. The paper presents another case study in the project of {\em proof mining}, which is concerned with the extraction of effective uniform bounds from (prima-facie) ineffective proofs.Comment: in C.S. Calude, G. Stefanescu, and M. Zimand (eds.), Combinatorics and Related Areas. A Collection of Papers in Honour of the 65th Birthday of Ioan Tomesc