The role of floor control and of ontology in argumentative activities with discussion-based tools

Argumentative activity has been found beneficial for construction of knowledge and evaluation of information in some conditions. Many theorists in CSCL and some empiricists have suggested that graphical representations may help in this endeavor. In the present study, we examine effects of type of ontology and of synchronicity in students that engage intuitively, without training, in e-discussions. Fifty-four Grade 7 students from two classes participated in the study. We tested the effects of using an informal argumentative ontology and control over turn taking on the average number of claims and arguments relevant to the issue at stake, the average number of different types of references to peers (productive. etc.), and on the number of chat expressions (nicknames, swear words, etc.). We found that when providing both an informal argumentative ontology and control over turn taking, students express less chat expressions and fewer references that are not new relevant claims or arguments to their peers, but express more relevant claims and arguments. These findings suggest the immediate beneficial role of the combination of an informal ontology and control over turn taking in the co-elaboration of knowledge.     

The Anticancer Activity of Organotelluranes: Potential Role in Integrin Inactivation

Organic Te^IV compounds (organotelluranes) differing in their labile ligands exhibited anti‐integrin activities in vitro and anti‐metastatic properties in vivo. They underwent ligand substitution with l ‐cysteine, as a thiol model compound. Unlike inorganic Te^IV compounds, the organotelluranes did not form a stable complex with cysteine, but rather immediately oxidized it. The organotelluranes inhibited integrin functions, such as adhesion, migration, and metalloproteinase secretion mediation in B16F10 murine melanoma cells. In comparison, a reduced derivative with no labile ligand inhibited adhesion of B16F10 cells to a significantly lower extent, thus pointing to the importance of the labile ligands of the Te^IV atom. One of the organotelluranes inhibited circulating cancer cells in vivo, possibly by integrin inhibition. Our results extend the current knowledge on the reactivity and mechanism of organotelluranes with different labile ligands and highlight their clinical potential.     

On the Power of Quantum,One Round,Two Prover Interactive Proof Systems

We analyze quantum two prover one round interactive proof systems, in which noninteracting provers can share unlimited entanglement. The maximum acceptance probability is characterized as a superoperator norm. We get some partial results and in particular we analyze the “rank one” case.      

Facilitating data exploration with query previews: a study of user performance and preference

Networked and local data exploration systems that use command languages, menus, or form fill-in interfaces rarely give users an indication of the distribution of data. This often leads users to waste time, posing queries that have zero-hit or mega-hit results. Query previews are a novel visual approach for browsing databases. Query previews supply users with data distribution information for selected attributes of the database, and give continuous feedback about the size of the result set as the query is being formed. Subsequent refinements might be necessary to narrow the search. As there is a risk that query previews are an additional step, leading to a more complex and slow search process, a within-subjects empirical study was ran with 12 subjects who used interfaces with and without query previews and with minimized network delays. Even with 12 subjects and minimized network delays statistically significant differences were found, showing that query previews could speed up performance 1.6 to 2.1 times and lead to higher user satisfaction.     

On the Relationship Between the Support Vector Machine for Classification and Sparsified Fisher's Linear Discriminant

We show that the orientation and location of the separating hyperplane for 2-class supervised pattern classification obtained by the Support Vector Machine (SVM) proposed by Vapnik and his colleagues, is equivalent to the solution obtained by Fisher's Linear Discriminant on the set of Support Vectors. In other words, SVM can be seen as a way to sparsify Fisher's Linear Discriminant in order to obtain the most generalizing classification from the training set.