Domain Specific Languages (DSLs) are claimed to increase productivity, while reducing the required maintenance and programming expertise. In this context, DSL usability by domain experts is a key factor for its successful adoption. Evidence that support those improvement claims is mostly anecdotal. Our systematic literature review showed that a usability evaluation was often skipped, relaxed, or at least omitted from papers reporting the development of DSLs. The few exceptions mostly take place at the end of the development process where fixing problems identified is too expensive. We argue that a systematic approach based on User Interface experimental validation techniques should be used to assess the impact of the new DSLs. The rationale is that assessing important and specially tailored usability attributes for DSLs early in language construction will ultimately foster a higher productivity of the DSL users. This paper, besides discussing the quality criteria, proposes a development and evaluation process that can be used to achieve usable DSLs in a better way.

n/a

n/a

Supply chains in an attempt to be more competitive, are adopting new management paradigm. Among these paradigms there are four that deserve particular mention because of their importance to better {SC} performance: lean, agile, resilient and green. The main objective of this paper is to propose a set of supply chain management practices to become the {SC} more lean, agile, resilient and green, which were named {LARG} practices, and to suggest a conceptual model that makes possible to analyze the influence of these {LARG} practices on manufacturing supply chains performance. Also, a set of operational, economic and environmental performance measures are suggested.

The mechanism proposed by Evans to justify the selectivity obtained in Lewis acid catalyzed Diels-Alder reactions of cyclopentadiene with acyloxazolidinones has been generalized and used in the rationalization of selectivities obtained in many other systems. However, we recently proposed an alternative mechanism, on the basis of open-chain mono- and bicomplexes, that avoids the need for chelates and explains the selectivity obtained by Evans. In this manuscript we apply our proposal to the catalyzed conjugated addition of amines to acylimidazolidinones, reported by Cardillo, and we clearly show that aluminum chelates are not involved in the reaction, as they induce no selectivity, while Cardillo observed high experimental selectivities. Our data equally show that bicomplexes with carbonyl parallel orientation, proposed by Cardillo to justify the experimental selectivity with nonchelating Lewis acids, indeed induce the opposite selectivity and have also to be dismissed. On the other hand, our mechanistic proposal allows for the full rationalization of the data obtained by Cardillo with aluminum, boron, or zinc Lewis acids and supports our previous proposal on DA cycloadditions of dienes to Evans chiral auxiliary derivatives.

n/a

Given graphs G and H and a positive number b, a weighted (H,b)-decomposition of G is a partition of the edge set of G such that each part is either a single edge or forms an H-subgraph. We assign a weight of b to each H-subgraph in the decomposition and a weight of 1 to single edges. The total weight of the decomposition is the sum of the weights of all elements in the decomposition. Let f(n,H,b) be the the smallest number such that any graph G of order n admits an (H,b)-decomposition with weight at most f(n,H,b). The value of the function f(n,H,b) when b=1 was determined, for large n, by Pikhurko and Sousa [Pikhurko, O. and Sousa, T., Minimum H-Decompositions of Graphs, Journal of Combinatorial Theory, B, 97 (2007), 1041--1055.Here we determine the asymptotic value of f(n,H,b)for any fixed bipartite graph H and any value of b as n tends to infinity.

No património edificado português as rochas granulares assumem importância relevante nos elementos construtivos presentes no património histórico e cultural, nomeadamente as pedras graníticas e areníticas. Tendo por objectivo a avaliação do comportamento mecânico de rochas granulares presentes no património edificado histórico foi realizado um estudo de investigação experimental sobre amostras dos litótipos seleccionados e que são representativos de rochas presentes no próprio edificado, em termos de propriedades petrográficas, físicas e mecânicas. Neste artigo apresenta-se um modelo analítico definido com base em ensaios experimentais que permite efectuar a simulação do comportamento das rochas em compressão uniaxial (diagramas de tensão-deformação), função de propriedades físicas e mecânicas obtidas através de ensaios não destrutivos e quasi não destrutivos. Este modelo permite desta forma a avaliação do comportamento mecânico de rochas granulares sem afectar a integridade do património histórico.

Eleven new tracks from the Upper Jurassic of Portugal are described and attributed to the stegosaurian ichnogenus Deltapodus. One track exhibits exceptionally well−preserved impressions of skin on the plantar surface, showing the stegosaur foot to be covered by closely spaced skin tubercles of ca. 6 mm in size. The Deltapodus specimens from the Aalenian of England represent the oldest occurrence of stegosaurs and imply an earlier cladogenesis than is recognized in the body fossil record.