This article introduces the web-based learning environment SQLearn, which allows learners to receive automated, individual feedback on the SQL queries. The SQLearn system performs a syntax check as well as a check of the semantic and structure of the formulated SQL query. To give feedback about semantic errors, the parse tree of the SQL query is compared with the parse trees of the sample solut...

Dans les projets décisionnels, la phase de définition des opérateurs d’extraction, transformation et chargement (ETLExtract-Transform-Load) des données dans l’entrepôt est souvent sous-estimée. Bien que ces tâches représentent (selon les spécialistes du domaine) à peu près les trois quart du projet décisionnel [13], les outils du marché n’offrent pas d’assistance. Le développeur est, par conséq...

the one-dimensional cutting stock problem, has so many applications in lots of industrial processes and during the past few years has attracted so many researchers’ attention all over the world. in this paper a meta-heuristic method based on aco is presented to solve this problem. in this algorithm, based on designed probabilistic laws, artificial ants do select various cuts and then select the...

Angiogenesis (the recruitment and formation of new blood vessels) may be a limiting step in the growth of tumors. Recent work in animal models of human cancer suggests that even transient angiogenic signals can irreversibly block tumor dormancy, promoting tumor growth. Another report concludes that the production of an-giogenic factors may result from activation of a signaling pathway in the in...

When cytotoxic T lymphocytes encounter an infected cell or a tumor cell, they establish an interaction interface with the target cell called the immunological synapse (IS). This interface is partly mediated by the T cell receptor (TCR). The structure of the IS resembles a ‘‘bulls-eye’’ with the TCR located in the central portion of this interface called the central supramolecular activation clu...

This issue's Immunology Select discusses recent studies on allergic responses in mouse models of human disease as well as how certain drugs, like the glucocorticoid dexamethasone, alleviate the symptoms of allergy. There are many similarities between the immune responses to allergens and to parasitic worms. In their new study, Reese et al. (2007) examined immune responses in the lung tissue of ...

Studying the molecular mechanisms that make the senses respond precisely to external stimuli continues to generate surprising results. This issue's Neurobiology Select discusses studies of the five senses that reveal new insights into protein function, physiology, and animal behavior. As a testament to their biological importance, odorant receptors are the largest gene family in vertebrates, wi...

This Biomedicine Select explores a cluster of recent papers that highlight traditional and new approaches to treating a variety of diseases—from a small-molecule inhibitor to treat temporal lobe epilepsy to cell replacement therapy for diabetes to a unique way to generate tumor-specific antigens. Epilepsy affects more than 50 million people worldwide and about 40% of those with the disease cont...