Yishay Mor
email: yishaym@gmail.com

Richard Noss
email: r.noss@ioe.ac.uk

Programming as mathematical narrative

Keywords: Narrative, programming, constructionism, situated abstraction, mathematical learning, collaborative learning, CSCL

This paper describes a narrative-oriented approach to the design and analysis of a computational system and a set of activities for mathematical learning. Our central contention is that programming can offer a key to resolving the tension between the different representational structures of narrative and mathematical formalism. In the course of describing our approach, we make a distinction between the epistemiccognitive elements of narrative and the social, cultural and affective elements. We then elaborate the theoretical grounds of the individual epistemic facets of narrative. We propose a link between narrative theories of learning and constructionist traditions, specifically the notion of situated abstraction. This link suggests the possibility of further dialogue between the two academic communities.

Introduction

Actually, it is half the art of storytelling to keep a story free from explanation as one reproduces it. [...] The most extraordinary things, marvellous things, are related with the greatest accuracy, but the psychological connection of the events is not forced on the reader. It is left up to him to interpret things the way he understands them, and thus the narrative achieves amplitude that information lacks.

Walter Benjamin (The storyteller,Illuminations,p. 86) This paper describes a narrative-oriented approach to the design and analysis of a computational system and a set of activities for mathematical learning. The language of mathematics is often perceived as propositional; a formalism which defines terms, states axioms and rules, then derives theorems and proves them. Its structures are static, devoid of time and person. This view was demonstrated lucidly by Wittgenstein: In mathematics we have propositions which contain the same symbols as, for example, "write down the integral of…" etc., with the difference that when we have a mathematical proposition time doesn't enter into it and in the other it does. (Wittgenstein, 1989, pp 34) This would appear to be antithetical to narrative form, which is always personal, contextual and timebound. By contrast, [START_REF] Bruner | Actual Minds, Possible Worlds (The Jerusalem-Harvard Lectures)[END_REF][START_REF] Bruner | Acts of Meaning: Four Lectures on Mind and Culture (Jerusalem-Harvard Lectures)[END_REF] shows, narrative is a powerful cognitive and epistemological construct. The main question we explore is: how can the epistemic power of narrative be harnessed in the construction of mathematical meaning?

We approach this question from a design perspective. We are concerned with the design of platforms, tools, and activities for mathematical learning, focusing on the notion of situated abstraction [START_REF] Noss | Windows on Mathematical Meanings : Learning Cultures and Computers (Mathematics Education Library)[END_REF]. The idea, (since developed in, for example, [START_REF] Noss | The Construction of Mathematical Meanings: Connecting the Visual with the Symbolic Educational Studies in Mathematics[END_REF], highlights the dynamics of constructing knowledge from activity, by inserting or populating an abstraction with meaning -in the shape of special cases, particular values, or familiar contexts (or, in the special case of the mathematical situation, with mathematical objects and relationships). The questions we ask include: what are the possible contributions of narrative that might facilitate such a trajectory? What is required from such narrative, and what is required from the learning activity encompassing it? In brief, we aim at elaborating the role that narrative could play in the construction of mathematical abstraction.

Our central contention is that programming can offer a key to resolving the tension between the different representational structures of narrative and mathematical formalism. We see programming as an expressive activity, a form of writing or composing, contingent on context and used purposefully to carry out actions. We claim that programming can afford a narrative form for representing mathematical meanings. The issues we address have strong social and cultural dimensions, and occasionally we refer to these. However, our goal is to highlight the often neglected aspects of individual knowledge construction within a social environment.

The structure of this paper is as follows. We begin by presenting a review of the use of narrative in educational theory in general and in the teaching of mathematics in particular. Inter alia, we present our own perspective on the relationship between narrative, learning and technology. We then briefly describe the WebLabs project and the tools developed for it, as an example of a narrative-aware learning environment. Following this, we present three illustrative episodes from our observations, and comment on the role of narrative in students' learning and in the design of technology to support it. Our concluding discussion highlights the potential of constructionist programming to provide students with a medium for mathematical narrative.

Narrative and education

The concept of narrative has been investigated extensively within a wide range of disciplines over the last few decades. To name but a few: in literary theory Gérard [START_REF] Genette | Narrative Discourse[END_REF] establishes narrative as a fundamental tool; in the social sciences Kenneth Gergen (1998) refers to it as a tenet of social construction; David [START_REF] Carr | Time, Narrative, and History (Studies in Phenomenology and Existential Philosophy)[END_REF] positions it as a central concept in the philosophy of history. Since the 1980s, narrative approaches have also become popular in counselling, where the term refers to a patient's personal account of her condition (White & Epston, 1990;[START_REF] Roberts | Narrative and severe mental illness: what place do stories have in an evidence-based world?[END_REF].

Our own interests centre on the epistemic role of narrative, in the tradition of Bruner. We focus on storytelling as a means of meaning-making, with an emphasis on the structural and semantic components of narrative. In reality, it is hard to separate the individual epistemic aspects of narrative from the social, affective and cultural aspects. Nevertheless, the emphasis in this paper is on the former. In his theory of learning and education, [START_REF] Bruner | Actual Minds, Possible Worlds (The Jerusalem-Harvard Lectures)[END_REF][START_REF] Bruner | Acts of Meaning: Four Lectures on Mind and Culture (Jerusalem-Harvard Lectures)[END_REF][START_REF] Bruner | The Narrative Construction of Reality[END_REF]1996;[START_REF] Bruner | Monolouge as Narrative Recreation of the World[END_REF] identified narrative as the predominant vernacular form of representing and communicating meaning. Humans use narrative as a means of organizing their experiences and making sense of them. Parents use narrative as a means of sharing knowledge with their children. [START_REF] Schank | Knowledge and Memory: The Real Story[END_REF] argue that stories about one's experiences, and the experiences of others, are the fundamental constituents of human memory, knowledge, and social communication. They call for a shift towards a functional view of knowledge, as [START_REF] Schank | Tell Me a Story: Narrative and Intelligence[END_REF] explains: "intelligence is really about understanding what has happened well enough to be able to predict when it may happen again" (p. 1). Such knowledge is constructed by indexing narratives of self and others' experiences, and mapping them to structures already in memory. While Schank and Abelson come from an AI perspective, their theory is supported by recent psychological studies. Atance and O'Neill (2005) define episodic future thinking as the ability to project oneself into the future to preexperience an event. This, they claim, is a uniquely human phenomenon which precedes semantic future thinking [START_REF] Atance | My future self: Young children's ability to anticipate and explain future states[END_REF], and provides the developmental basis for skills such as planning and causal reasoning. They found that episodic future thinking emerges around the age of four, and is related to children's abilities to construct and comprehend verbal accounts of experiences. Recent developments suggest a neural basis for the role of narrative in the abstraction of daily experience to knowledge [START_REF] Mar | The neuropsychology of narrative: story comprehension, story production and their interrelation (review)[END_REF]. Narrative comprehension engages a widely distributed network of brain regions, and is clearly distinct from basic language comprehension [START_REF] Nichelli | Where the brain appreciates the moral of a story[END_REF][START_REF] Ferstl | Emotional and Temporal Aspects of Situation Model Processing during Text Comprehension: An Event-Related fMRI Study[END_REF][START_REF] Xu | Language in context: emergent features of word, sentence, and narrative comprehension[END_REF].

Following Bruner, we define narrative as a progression of statements describing something happening to someone in some circumstances. This view entails a form of language which includes a context (setting) and a plot: a sequence of events bound by temporal -and implicitly causal -relationships. Likewise, [START_REF] Mar | The neuropsychology of narrative: story comprehension, story production and their interrelation (review)[END_REF] identifies the presence of a causal-temporal event structure as imperative, and notes: "The most basic elements of a story include a setting, and an agent who holds a certain goal […] and whose progress towards that goal is impeded […] or facilitated by certain events" (p 1415). In this paper, we explore three constituents of narrative: context, plot and moral. The context includes the background information assumed or conveyed explicitly with a narrative. The plot denotes its temporal and causal structure. We use the term moral to refer to the implicit endpoint of a narrative, the purpose for which it is told.

A narrative is always contextualized. An important contextual element is the exposition, which lays out the context: time, location, props and characters. Such an exposition is not limited to imaginative narrative: it also appears in scientific texts [START_REF] Bruner | Actual Minds, Possible Worlds (The Jerusalem-Harvard Lectures)[END_REF]. One particular element of context we focus on is the idea of voice, which relates to the presence of the speaker. Even in allegedly 'de-humanised' arenas, such as scientific or legal writing, great significance is attached to the voice of a document's author. When approaching a scientific paper, one draws on knowledge of the author: past publications, close collaborators, institution, etc. Likewise, when writing a paper, one is advised to imagine its readers and engage in a dialogue with them. Familiarity with the writer's personal style makes the writing much easier to interpret and understand. A clear sense of authorship promotes responsibility for the text.

A well-formed narrative must maintain coherence of temporality and causality [START_REF] Gergen | Narrative, Moral Identity and Historical Consciousness: a Social Constructionist Account ("Erzahlung, moralische Identiat und historisches Bewusstsein. Eine sozialkonstructionistische Darstelung[END_REF]. Temporality refers to the chronological ordering of events. In the light of narrative intelligence theory (see [START_REF] Mateas | Introduction to the Narrative Intelligence Symposium[END_REF], it is clear that maintaining the temporal structure is crucial to the reader's ability to comprehend a story. The identification of temporal affinity of events also plays a strong role in learners' inferences of causality, an important component in the construction of meanings. The sequencing of events is referred to as the plot. [START_REF] Gergen | Narrative, Moral Identity and Historical Consciousness: a Social Constructionist Account ("Erzahlung, moralische Identiat und historisches Bewusstsein. Eine sozialkonstructionistische Darstelung[END_REF] adds that events are carefully selected to support an endpoint.

Yet perhaps the most important part of a narrative is typically left unstated: its moral. We use this term with an expanded meaning, referring to the narrative's implicit endpoint. A story is told for a purposeestablishing norms, conveying knowledge, or raising a question. It is the implicit layer that holds the narrative together -the causal relationships along the way and the climactic moral at the end. Without them, all we have is an arbitrary list of events. As [START_REF] Mar | The neuropsychology of narrative: story comprehension, story production and their interrelation (review)[END_REF] asserts, "If a well-crafted story contains mention of an event or character, it is assumed that this element is in some way relevant to the goals of the protagonist." (ibid, p. 1416) Recent advances in neural psychology ground these observations in new understandings of the brain's inner working (Mar et al, in press;[START_REF] Mar | The neuropsychology of narrative: story comprehension, story production and their interrelation (review)[END_REF]Holyoak & Krogen, 1995;Young & Saver, 2001;[START_REF] Addis | Characterizing spatial and temporal features of autobiographical memory retrieval networks: a partial least squares approach[END_REF][START_REF] Mason | How the Brain Processes Causal Inferences in Text. A Theoretical Account of Generation and Integration Component Processes Utilizing Both Cerebral Hemispheres[END_REF]. [START_REF] Xu | Language in context: emergent features of word, sentence, and narrative comprehension[END_REF] link context to brain regions responsible for global semantic processes such as inference, coherence, conceptual association and text integration. Other findings point to a strong link between narrative comprehension and theory-of-mind processing [START_REF] Mar | The neuropsychology of narrative: story comprehension, story production and their interrelation (review)[END_REF], suggesting that the cognitive modelling of the storyteller and the protagonists is a critical constituent in understanding a story. A detailed discussion of the relations between neural and cultural theories is called far, but is beyond the scope of this paper.

Closer to home, the mechanism described above is consistent with the ideas of situated abstraction and webbing [START_REF] Noss | The Construction of Mathematical Meanings: Connecting the Visual with the Symbolic Educational Studies in Mathematics[END_REF][START_REF] Noss | Windows on Mathematical Meanings : Learning Cultures and Computers (Mathematics Education Library)[END_REF]. The concept of situated abstraction focuses attention on the process of making meanings through activity. It highlights the fact that this process is situated in a context, and thus the linguistic and conceptual resources made available for expressing meaning are rooted in that context. Abstraction is achieved within, not above, context. Mathematical knowledge is constructed and expressed with available tools (physical, linguistic, digital or social) that may not map trivially to standard mathematical notation. People situate abstraction by webbing together meaning from artefacts, actions, symbols and context. Our current perspective on narrative as an epistemic vehicle elaborates the ideas of situated abstraction, by demonstrating one mechanism by which this layering and webbing works. The neuropsychological evidence gives direct support to the ideas of layering and webbing, albeit using a different terminology. For example, [START_REF] Addis | Characterizing spatial and temporal features of autobiographical memory retrieval networks: a partial least squares approach[END_REF] talk about 'specific and general autobiographical memories' (p 1740), and show that these activate the same regions in the brain. Or, in the words of Mason & Just (2006): "Text attributes at the discourse level enter into combinations with other information to allow a reader to weave individual sentences into an integrated narrative structure. The resulting conceptual structure incorporates pragmatic information and connects the text with the reader's world knowledge."

Coming from a design research methodology (Mor & Winters, 2007), we take the concepts of narrative both as analytical tools and as design guidelines. The analytical dimension asserts that we interpret learners' expressions as mathematical narratives, that is to say, narratives which are intended to communicate or construct mathematical meanings. This approach lends itself naturally to verbal and written expressions; our argument is that it could also be applied to other modalities -including graphics and programming. A similar claim is voiced eloquently by Healy and Sinclair (2007).

As for the role of narrative in design, the challenge is to engender situations for mathematical learning that acknowledge forces such as voice, context and plot. Our argument is that it is necessary to find interpretations of these terms which have inherent mathematical meanings. In other words, the context has to be a mathematical context, the plot has to be a mathematical plot and its moral -the implicit endpointmust be mathematical.

Given the strong cultural and neurological grounding of narrative, it seems that we should strive to embed narrative structure in the design of systems or activities which are aimed at meaning-making. However, narrative approaches to computer-enhanced learning are often focused on designing systems that support narrative-based learning [START_REF] Mott | Towards Narrative-Centered Learning Environments[END_REF][START_REF] Decortis | New Active Tools for Supporting Narrative Structures Personal Ubiquitous Comput[END_REF][START_REF] Decortis | Survey of narrative theories for learning environments[END_REF], i.e. systems that support the production of imaginary narrative as the site of learning. [START_REF] Nehaniv | Narrative for Artifacts: Transcending Context and Self In Narrative Intelligence: Papers from the 1999[END_REF] argues for a broader view, claiming that any design that does not acknowledge the "narrative grounding" of humans will appear to its users as bizarre, unintelligent and unintelligible.

… it is desirable to take into account that humans are temporally grounded, narratively intelligent beings. Their evolutionary heritage leads them to expect that the actions of others are embedded in a context of past history and future events." (Nehaniv, 1999, pp. 102) Likewise, [START_REF] Laurillard | Affordances for Learning in a Non-Linear Narrative Medium[END_REF] highlight the importance of embedding narrative structure in the design of multi-media resources, where non-linearity risks impeding learners from maintaining a personal narrative line and thus increasing cognitive costs. It is the responsibility of teachers and designers to maintain narrative flow in order to allow learners to maintain a focus on the development of sound arguments: "With such design features, the non-linear medium is able to afford something more than mere browsing: it will afford structured, meaningful learning" (p 18).

Mathematics and Narrative in Education

When we say 'two plus two equals four', the truth value of this statement is independent of when we say it or who 'we' are. Yet how do we present such a statement to a young child? One might say:

You had two marbles, and I gave you two more, so now you have four.

When we attempt to humanise the mathematical statement, we unconsciously transform it from the propositional form to the narrative. Something (transfer of marbles) happened to someone (the child and me) under some circumstances (say, sitting around the kitchen table). In that event, two groups of two were magically exchanged for one group of four.

Such conversions from propositional to narrative do not disappear as the subject matter becomes more elaborate. Let us review one more example:

{S i } → C ≡ for each ε there exists N such that for every n > N, |S n -C| < ε How do we explain such a statement to a student? Perhaps:

Let's look at the sequence we had yesterday {1, 1/2, 1/3…}. Go far enough along the sequence and you will reach a point such that all subsequent terms within a very small range of 0. Now, we can make that small range as small as we want.

Again, in our attempt to make the mathematical idea accessible, the propositional is rendered as a narrative. A static structure, 'devoid of time and person', is placed in a specific context, and becomes a string of events happening to 'you'. However, this symbiosis is short lived. Very quickly, the student is asked to abandon the narrative discourse and pick up the propositional form, to use algebraic symbolism in its static interpretation, a demand expressed by Solomon and O'Neill (1998): "Mathematics can be embedded in a variety of texts in a variety of styles from dialogue [...]. This, however, is quite distinct from linguistic features constitutive of mathematical discourse itself: mathematics cannot be narrative for it is structured around logical and not temporal relations". (p 217) Solomon and O'Neill reject the idea that "Children could re-invent mathematics by abstracting it from the world around them" (p 217): for them mathematics is a strict social practice, with distinct rules of genre. This requirement, they readily admit, gives rise to a dissonance between the students' interpretation of the symbols and the one expected by their teachers. We ask: is the static, disembodied form a necessary feature of mathematical language? A historical perspective suggests that there are other possibilities for mathematics' notational infrastructure, and that the static formalism may have been optimised for static media [START_REF] Kaput | Developing new notations for a learnable mathematics in the computational era[END_REF]. Do new media offer new opportunities -can there be a representational system that allows us to express mathematical concepts adequately in a narrative form?

We are not alone in challenging the static view of mathematics. Indeed, Healy & Sinclair (2007), in a studied response to Solomon & O'Neill (1998), argue that the latter's position overlooks the possible role of narrative in more personal acts of understanding. Many testimonies show an alienated experience of mathematics. This barrier can be breeched by allowing space for learners' personal narratives, relating mathematical meanings to their own experiences and reflecting on their individual learning trajectories. We contend that the chasm runs deeper: it is not, as Solomon & O'Neill (1998) phrase it, a debate between "an emphasis on authorship and creativity versus an emphasis on understanding genre" (p 210). It is a question of what is the mathematics we wish to teach: a practice, or a phenomenon, a noun or a verb? Should children learn to see mathematics or to do mathematics? Perhaps both, but then -which comes first? Solomon & O'Neill (1998) present an example of two texts by William Rowan Hamilton, one from his published letters and the other from his more formal publications. But while they see the former as literature and the latter as mathematics, Healy & Sinclair (2007) see one as a window on the process of doing mathematics, and the other as the output of that process. They inspect various reports of mathematician's personal experiences, and find that all have temporal structure, and carry a strong sense of voice. [START_REF] Bruner | The Narrative Construction of Reality[END_REF] distinguishes between scientific knowledge, which is organised by logical principles, and cultural assets, what he calls "folk psychology", which he argues are "orgenized narrativly" (p 21). He calls for a shift of attention which would honour both forms of knowledge. Nevertheless, this distinction does not preclude representing and learning of scientific and logical knowledge in narrative forms. Indeed, [START_REF] Bruner | Actual Minds, Possible Worlds (The Jerusalem-Harvard Lectures)[END_REF] notes two modes of thinking, mapped to two genres of narrative -paradigmatic and imaginative. Paradigmatic narrative is top down, seeks generality and demands consistency. Imaginative narrative is bottom up, seeks specificity and demands coherence. Several researchers have suggested that in order to provide learners with tools for coping with unfamiliar problems, they need to share the experiences of those who posses such tools. [START_REF] Burton | Mathematics, and its learning, as narrative? A literacy for the twenty-first century In Challenging Ways of Knowing in English, Maths and Science[END_REF] argues that this points to a need to facilitate learners' authoring of their accounts of how they came to know mathematics. These narratives are personal, i.e. imaginative, as they are general and paradigmatic. [START_REF] Livingston | The Context of Proving[END_REF] calls for an educational approach to mathematical proof that acknowledges the context in which proofs are constructed and the personal path taken by those who prove. Although he does not refer explicitly to the notion of narrative, we find many parallels in his situated view of proof. [START_REF] Morgan | Mathematics and human activity: representation in mathematical writing In Research in Mathematics Education[END_REF] also distinguishes between mathematical 'facts' and 'activity'. Inspecting several mathematical texts, she identifies elements of temporality and personalisation, similar to the constituents of narrative we noted. Morgan argues that rather than rejecting such style as 'inappropriate', we should ask: what are the criteria for a personal narrative to qualify as an account of mathematical activity?

The model of narrative comprehension we presented above provides further support for these arguments.

We saw how developing a theory-of-mind is fundamental in narrative comprehension. Likewise, if we want children to learn to think and act like mathematicians they need to develop a theory of mathematical mind: the ability to imagine "how a mathematician approaches this problem", and what better way then through mathematical narratives? Furthermore, our minds are geared towards extracting causal structures from the temporal sequencing of a narrative. "The queen died, then the king died" is transformed to "if queen dies, then king dies" (with apologies to E.M. [START_REF] Forster | Aspects of the Novel[END_REF]. So, counter to Solomon & O'Neill's claim, it may be possible that children will invent mathematical structure by abstracting it from the narratives around them -be it those they receive, or those they construct. Indeed, O'Neill et al ( 2004) find a surprising correlation between children's performance in generating narratives at the age of three to four, and their mathematical abilities two years later. This correlation is unique: general language skills were neither predictive of mathematical achievement nor where narrative skills predictive of spelling skills or general knowledge. They suggest that the same skills which underlie narrative comprehension form the basis of mathematical thinking: inference of relationships and logical chains.

Our approach is in agreement with many of the assertions of the emerging discourse approach to mathematics (Kieran, Forman & Sfard, 2002). Perhaps the main distinction is that we focus on the micro, individual, epistemic facets of discourse while most of the research in this framework emphasizes the social and cultural aspects of cognition as communication.

Narrative learning environments and mathematics

We wish to differentiate between three types of systems: Interactive narrative games, narrative learning environments and environments with narrative elements.

The first group includes interactive storytelling and interactive drama environments, such as Façade (Stern & Mateas, 2005) and Storytron [START_REF] Crawford | Chris Crawford on Interactive Storytelling[END_REF], that are designed to engage participants in an enhanced dramatic experience. Most of the work in this field stems from a gaming and game design tradition. While learning is acknowledged, other qualities are highlighted, such as aesthetic experience and pleasure.

Narrative learning environments, the second group, are designed from the premise of narrative as a defining factor in learning [START_REF] Mott | Towards Narrative-Centered Learning Environments[END_REF][START_REF] Dettori | Technology-Mediated Narrative Environments for Learning[END_REF]. In this case, learning is the aim and narrative is the primary means, manifested in technological tools. Many of the efforts in this category come from an AI background, with an emphasis on narrative agents. Systems in this category, such as Teatrix [START_REF] Paiva | dramatis personae in a virtual story creation environment[END_REF], often share the interactivity and dramatic qualities of the first, but with a shift of emphasis from playing to learning. Some even attempt to appropriate these characteristics to a mathematical domain [START_REF] Alexandre | Maths goes to play… presented at the 2nd Kaleidoscope Workshop on Narrative Learning Environments[END_REF].

The third class of technologies are interactive learning environments which acknowledge narrative elements [START_REF] Back | Talking About Mathematical Problems on the Web[END_REF][START_REF] Sarmiento | Co-constructed narratives in online, collaborative mathematics problem solving[END_REF][START_REF] Stahl | Shared referencing of mathematical objects in chat presented at the International Conference of the Learning Sciences[END_REF][START_REF] Yukawa | Co-reflection in online learning: Collaborative critical thinking as narrative[END_REF], either in their design, in their use or in their analysis. These studies typically emerge from a general CSCL tradition, assimilating ideas of narrative into existing frameworks of technology enhanced learning. The systems in this category may be traditional interactive learning environments with an added discursive or reflective element. In other cases, we find pedagogical innovations using ubiquitous social software, such as blogs [START_REF] Makri | Design and implementation of a learning environment for asynchronous communication and collaboration among mathematics teachers, based on narrative principles presented at the 2nd Kaleidoscope Workshop on Narrative Learning Environments[END_REF] or wikis [START_REF] Yukawa | Co-reflection in online learning: Collaborative critical thinking as narrative[END_REF].

Our work falls into the last category. The reason for this is quite simply that we set out to create an environment for mathematical learning. Our initial notions of narrative were, in all honesty, vague and naïve. It is through the iterative process of design research that these ideas were refined, and their presence in the design amplified. This process inevitably left us with some rough edges, but it also led us to discover narrativity in unexpected places.

In the remainder of this paper, we demonstrate our approach, based on creating situations in which students have an incentive to make formal arguments and to challenge the validity of each other's statements, adopting narrative forms that are themselves embedded in a formal expressive system that allows mathematical ideas to be developed and shared. We begin by describing the context of our work.

We then review three illustrative episodes.

WebLabs

The examples below are derived from The WebLabs Project (www.weblabs.eu.com), which has been described in detail elsewhere (Mor et al, 2006;[START_REF] Simpson | Exploring the mathematics of motion through construction and collaboration[END_REF]. We will only mention briefly those elements that are essential for the topic at hand. The project aimed at exploring new ways of constructing and expressing mathematical and scientific knowledge in communities of young learners. The WebLabs project involved several hundred students, aged ten to fourteen, across sixteen schools and clubs in six European countries. Our approach brought together two traditions: constructionist learning as described by [START_REF] Papert | Constructionism[END_REF] and collaborative knowledge-building in the spirit of [START_REF] Scardamalia | Computer support for knowledge-building communities[END_REF]. The former was largely supported by the programming language ToonTalk [START_REF] Kahn | ToonTalk -An Animated Programming Environment for Children[END_REF]2004) (www.toontalk.com), whereas for the latter we have designed and built a web-based collaboration system called WebReports [START_REF] Mor | Designing for cross-cultural web-based knowledge building In The 10th Computer Supported Collaborative Learning[END_REF]. The central design intention of our approach is that students should simultaneously build and share models of their emerging mathematical knowledge.

ToonTalk (Figure 1) is a language and a programming environment designed to be accessible by children of a wide range of ages, without compromising computational and expressive power. Following a video game metaphor, the programmer is represented by an avatar that acts in a virtual world. Through this avatar the programmer can operate on objects in this world, or can train a robot to do so. Training a robot is the ToonTalk equivalent of programming. The programmer leads the robot through a sequence of actions, and the robot will then repeat these actions whenever presented with the right conditions. ToonTalk programmes are animated: the robot displays its actions as it executes them.

Figure 1: The ToonTalk programming environment. The programmer's avatar is on the right, and a robot generating a sequence of numbers in the centre.

The WebReports system (Figure 2) was set up to serve both as a personal memory aid and as a communication tool. A web report is a document that is composed and displayed online, through which a learner can share experiences, questions and ideas derived from her activities. The uniqueness of our system is that it allows the author to share her ideas not just as text, but also graphics and animated

ToonTalk models. This last point is crucial: rather than simply discussing what each other may be thinking, students can share what they have built, and rebuild each others' attempts to model any given task or object.

Figure 2: The WebReports collaboration environment. A student's report and peer comments, both incorporating embedded ToonTalk objects.

A main concern was the careful design of a set of activities, aiming to foster learning of specific mathematical topics, such as sequences, infinity and randomness. The choice and design of technologies was subordinate to this cause. In that sense, our environment is not a narrative learning environment per se, but rather a narrative-aware learning environment. It supports construction, collaboration and exploration by providing learners with a Narrative space: a medium, integrated with the activity design, which allows learners to express and explore ideas in a narrative form. The examples in the next section aim to elucidate these ideas.

A few illustrative episodes

We will review several episodes from a strand of activities on number sequences. While an extensive narrative-oriented analysis of our data has yet to be presented, we will use these examples to demonstrate our two-way approach: on the one hand, interpret learners' expressions as narrative, and use this lens to understand their learning process. On the other hand, we will identify the relationship between the learners' modes of expression and the design of the learning environment.

Episode I: Adding up

Our first snapshot is taken from an experiment conducted in London in autumn 2004. This experiment involved a group of 10 boys, aged 13-14, for six one-hour sessions and a full day workshop. One of the first activities we conducted focused on generating and understanding partial sum series, using the Streams design pattern (Mor et al, 2006). Participants where asked to create one robot which generates a sequence of numbers, and feed its output to a second robot which sums the terms. Traditionally in such contexts, a sequence would be represented by a list: a static array of the first n terms of the sequence. The Streams pattern replaces this structure with a dynamic process that generates the terms on the fly, and passes them from one module to the next, in a manner similar to a factory production line. Rather than seeing the sequence as a fixed and finite array of numbers, students observe and manipulate a continuous, dynamic and potentially infinite entity. The standard representation of numbers and commas is replaced by a string of events with a temporal and casual structure.

The following fragment is taken from a group discussion. Using the electronic whiteboard, Alan had just demonstrated how he constructed and connected the two robots. The first robot, called add-a-num, generates the natural numbers by iteratively adding 1 to the current term. By replacing this 1 with a variable, it can be generalized to any arithmetic sequence. The second robot sums the terms of the first sequence as they are generated, producing a series of partial sums. In the case of natural numbers, this is the sequence {1, 3, 6, 10…}.

As we watched Alan's robots in action, Peter was asked to provide a commentary on their actions.

1.Peter: Ok , huh, well, the robot's taking the numbers from the nest.

2.CH:

Which robot?

3.Peter:

The 'add up' robot is taking the numbers from the nest which says numbers I think, and the numbers in the numbers nest are coming from the other sequence which the other robot is doing so he's taking these numbers and he's adding them on to the total creating a different sequence out of the other sequence. Phrase (1) shows some confusion and hesitation. Phrase (3) exhibits a specific narrative of the events on the screen. We see a simultaneous process of narrative comprehension and construction. Peter observes Alan's animated narrative, and reconstructs it in words.

Reading Peter's expressions, several issues emerge. First, notice the narrative structure of both phrase (3) and ( 5). In (3), the 'add up' robot is the protagonist, going through a string of events. The purpose of add up's actions is to 'create a different sequence out of the other sequence'. But what is that sequence? This is left unsaid. In ( 5) we see a temporal structure and a protagonist, except that the identity has changed: now it is the sequence. What we see is the rule of the sequence expressed in narrative form. Replace 'going up in one' with 'natural numbers' and 'adding that number to the total' with 'partial sums of' and we get the standard definition.

Peter's narrative in (3) is already an abstraction. Children who have not constructed such a robot would describe what they see in a procedural manner: 'the bird brings in the number', 'the mouse bams it on to the other number'. In constructing his narrative, Peter chooses the events which are worth noting, those that serve the mathematical moral of the tale: creating one sequence from another. It is Peter's own experience in modelling this idea that allows him to connect the events he sees before him to his own episodic memories, and shift from a specific narrative to a generic one. On the other hand, capturing this idea as a tale of two robots gives the mathematical concept a narrative body.

It is important to note the blending of the technology into the classroom culture. While the use of programming and the display of animated code on the whiteboard are technologically advanced, the discussion itself -the narrative space, is conducted in a traditional classroom environment. When designing digital environments for collaborative learning, such a narrative space needs to be preserved if we want them to be educationally powerful.

Episode 2: Joe999's robot

The partial sums activity was followed by a game called Guess my Robot (GmR). In this game, students challenge each other to reconstruct the robots they used to produce complex number sequences. A mathematical analysis of this game is presented in Mor et al (2004), and a more elaborate narrativeoriented analysis is available in Mor & Noss (2004).

Joe999 was the self-adopted WebReports nickname of an 11-year-old boy from London. His group worked on a different activity, and he was not initially involved in the Guess my Robot game. Having found his way to the game in a round-about manner, he started from a relatively advanced challenge: {11, 7. 5, 5.75, 4.875, 4.4375}, and responded by posting a textual comment:

1. Joe999: Yish. After 10 minutes I figured out how to do the sequence. You take away 3.5. Then you find half of 3.5 and take that away from 11 and continue this sequence.

Such a response would be disqualified by many teachers. It is unclear what you 'take away 3.5' from, where the 11 comes from, and how you 'continue this sequence'. Reading this as a narrative, one can infer that Joe999 knows the answer. He assumes that the context is known. This context includes the box with the initial term of the sequence, and the fact that ToonTalk robots repeat the action they were trained to do. Nevertheless, our goal is to lead him to express his knowledge in rigorous form. Thus, YM responded:

2. YM: Don't just talk. ToonTalk. Instead of telling me you figured it out, build a robot (or chain of robots) that produces this sequence.

Joe999 took up the gauntlet, and trained a robot. To our surprise, this robot did not produce the challenge sequence -it acted out the story of how Joe999 had solved the puzzle! The robot takes the differences of the sequence, arranges them in a box and labels them: Joe999 appropriated ToonTalk to create his own narrative medium. Without any guidance from the researchers, he had used programming as a way of making a mathematical argument. He has retold the narrative from excerpt (1), yet in a form that is precise and succinct in nature, leaving no room for ambiguity. Joe999 does not have the linguistic tools to express himself accurately in text, but when programming -one has no choice but to be mathematical.

The genre dimension in Joe99's work is fascinating: taking ToonTalk programming as a shared cultural asset, he uses the execution of a program as the framework for telling his story. As Bruner notes, "it is by virtue of this embeddedness in genre … that narrative particulars can be 'filled in' when they are missing from an account." (Bruner, 1991, pp. 7). Indeed, the narrative of Joe999's robot would make little sense to a reader unfamiliar with ToonTalk programming.

The context of Joe999's narrative is given by the facilities of the WebReports and ToonTalk environment, and then enhanced by Joe999 in his packaging of the robot. Referring to emergent conventions, he positions the robot and its inputs in a manner that will ease the entry of potential readers into his narrative.

Joe999 meticulously assembles his plot. The robot goes through a carefully chosen sequence of actions and events. As with any good plot, Joe999's code has a moral. The purpose of the protagonist's (the robot's) actions in the story is not their immediate outcome (a box of numbers, a block of text), but the implicit transfer of an idea from Joe999 to his "readers": to convince them that Joe999 has uncovered the structure of the sequence.

Even the message that the robot prints has narrative characteristics: there is a protagonist ('you are..'), a progression of events ('halving the number you halved before'), and a sense of personal voice. The robot acts as an avatar for Joe999, expressing his conviction and emotion when typing "I have shown this in this box. Good sequence though Yish". Yet, the vague description in (1) has been replaced by the more generic and precise 'halving the number you halved before'.

Episode 3: 'fatal mistake'

The last phase of our number sequence activities focused on partial sums of converging sequences.

Students constructed robots to produce various converging sequences they proposed. They then conjectured about the behaviour of the partial sums of these sequences, and used the add-up robot from the first activity to test these conjectures. The students published their constructions along with their observations as they progressed. In this episode we focus on one of the students in the group mentioned in episode one. We refer to him by the nickname he chose for himself: Sodapop. His report streamlines text, graphics, excel charts and ToonTalk robot. We include only the text here, but refer the readers to the original at: http://www.weblabs.org.uk/wlplone/Members/sodapop/my_reports/Report.2005-03-22.2632.

Sodapop was exploring the reciprocals sequence {1, 1/2, 1/3, 1/4…} and its partial sums. After constructing the sequence, he plotted its terms and used a paint program to overlay his prediction of the graph of the partial sums on the image. The difference in style between this excerpt and verbal expressions by Sodapop and his friends suggest that putting his words into a public medium may have enhanced Sodapop's audience awareness (Mor at al, 2004). Some of the stylistic decorations are just that ('primary source between 99 and 101), and indeed in a follow up interview Sodapop admitted they were there to impress. Yet stripped of those, the text makes an interesting argument -expressed in narrative form. It is 'you' who 'have a number' and then progress through a line of actions. Unfortunately, the argument itself is flawed. But as with every good narrative, the important part is left unsaid. Sodapop is not telling the tale of the harmonic sequence. He is reporting on a process of inquiry: he had a theory; he tested it and found a counter-example, and consequently searched for a new theory.

While learners may be led through such a process many times, it is hard to get them to reflect on it and adopt it as a meta-cognitive strategy. Perhaps by giving Sodapop an opportunity to organise this experience as a narrative, we have allowed him to reflect on it at a higher level. Here is an important lesson in design: had we built strong scaffolding into the WebReports system, forcing Sodapop's expression into a structural mould, the narrative space would have been lost, and with it an opportunity for learning -both for him and for his peers who read his account.

Conclusions

This paper attempts to bridge the divide between narrative and formal language, by positioning programming -or rather, a particular form of programming -as a mediating linguistic form. We have explored this question by examining three episodes from the WebLabs project, in which children use programming and web-based discussion to conduct mathematical investigations. We have proposed a narrative-oriented framework for design and analysis of mathematical learning activities and the computerenhanced means of supporting them. The main elements of this framework are context, plot and moral (in the sense of an implicit conclusion). This framework was used to analyse a software system and the activities it affords.

We opened with the question of how to harness the epistemic power of narrative in the construction of mathematical meaning, arguing that computer programming holds that potential. Like narrative, computer programs operate in a specified context, have a temporal structure (or "plot") with underlying causal reasoning, and involve "actors" and "objects" -in fact, such terms are habitually used in software design. Yet like mathematical language, computer programs do not tolerate ambiguity and inconsistency. They are no less valid than algebraic formulae as a means of mathematical expression. Writing a program means taking the story of a phenomenon and restructuring it into formal statements. Once this is done, the programmer's ideas are reified in an object that can be passed around, examined, manipulated and argued about. This is not to say that all programming is narrative, and certainly not that narrative is all that programming is. Our intention is to highlight the narrative dimension of programming and its contribution to mathematical learning. Thus, one could argue that a procedural language such as Pascal is higher on the narrative scale than a declarative language such as Prolog, and that this difference may provide an insight as to their suitability as educational tools. From this perspective ToonTalk is a rather special case. It is, as we have seen, a system which is based on the idea of a narrative: the objects are characters, some with well-defined characters, programs can only be 'read' in real time, and the running of a program involves a story unfolding on the screen.

Let us recall one of the examples we gave earlier, so that we can now view it through the window of a ToonTalk program.

{S i } → C ≡ for each ε there exists N such that for every n > N, |S n -C| < ε and, in contrast,

If you go far enough along the sequence, you reach a point such that all subsequent terms are within a very small range of some constant, and that small range can be as small as we want.

There is little doubt that the essence of the first statement is captured in the second, and that in terms of grasping the key abstraction involved, the latter is much more intelligible. Its intelligibility lies partly in the lack of symbols (why symbols render a text unintelligible is another matter, but we should recall the advice given to Stephen Hawking by his editor that every equation in his book would halve the number of readers!). Clearly, the narrative nature of the sentence is, as we have pointed out earlier, also a key consideration.

Nevertheless, something is lost. It is extremely difficult to manipulate the latter expression, to use it to, say, prove some alternative theorem, to quantify how small ε can be for a given N. It is, in fact, rigorous only as a narrative, and it is this limitation that leads to the mathematician's privileging the symbolic text as exemplified in the first formulation. The problem is that while both are abstractions, the latter is an abstraction that is situated in time, and for that luxury one has to sacrifice the utility of the expression for generating new results.

The examples of ToonTalk programming above suggest a way to avoid having to make this difficult choice. By situating abstraction in time and space, abstraction can be given meaning, situated within a narrative. So what, in formal settings is regarded as unnecessary 'noise' in terms of narrative gained at the expense of utility and rigour, becomes constitutive of mathematical meaning. Indeed, this is, we think, a special case of a more general observation, that the noise of a situation -be it contextual cues, social setting, or implicit narrative -is crucial to meaning making and thus to learning. By embedding narrative elements in the design of the WebReports collaborative system, utilizing the narrative features of the ToonTalk programming language and applying a narrative-oriented approach to the design of activities, we have enabled students to utilize their narrative intelligence in constructing mathematical knowledge.

We do not claim to have resolved the questions we raised. At most, we hope we have convinced the reader that they are worth consideration. We argued for the value of observing narrative as a cognitive structure, yet some work still needs to be done to obtain a clear definition of narrative from a cognitive perspective, identify the atomic unit of narrative, and gain a better understanding of the relations between narrative, embodiedness and neuropsychology.

There is also a notable difference between the narrative present in most of the literature and that expressed in programmed code. The former is predominantly a recount of past events, whereas the latter is a recipe for affecting future events. This distinction needs to be elaborated. In a way, programming is a form of fantasy: but perhaps so is mathematics?

We have distinguished between social, cultural, affective and epistemic facets of narrative, and limited our discussion to the latter. While we feel it is important to highlight the often neglected individual aspect of narrative, this separation is somewhat induced. It remains to be explored how these different facets interact. In fact, even programming needs to be considered in a social context. After all, assembly languages aside, code is written to be read by humans. The notion of theory-of-mind is a possible link between the social context and the individual construction of knowledge. This link needs to be explored by combining diverse perspectives. One particular aspect is learners' anthropomorphism of code in the process of constructing or reading of programs, with ToonTalk robots as a special case.

The surprising correlations between social theories of narrative, situated abstraction and recent neurological models need to be explored. On one hand, being able to ground the social theory in the workings of the brain provides depth and credibility. On the other hand, most neurological models of learning seem largely based on individualistic or even behavioural frameworks, and might be enriched by social and cultural dimensions.

While most of the literature focuses on narrative comprehension, the nature of our activities led us to emphasize narrative construction. It would be interesting to complement that with observations regarding the epistemic effects of 'reading' ToonTalk code and peer reports. A hint at this potential is given in Mor & Noss (2004), but more needs to be done. Similarly, while we believe that we have demonstrated the potential of programming as mathematical narrative, we do not know how to prescribe a method to manifest and exploit this potential. Future research needs to identify design patterns (Mor & Winters, 2007) for creating narrative spaces.

A call for narrativity or situatedness of any kind should not be taken as an excuse for lack of rigor. A solid pedagogy informed by the idea of situated abstraction strives to design settings in which the desired mathematical concepts can be derived as a necessity of the learners' activity, generating situations in which phenomena 'beg to be organised' (Freudenthal, 1983, p.32). The site of learning has to have integrity as a narrative -but it must also have mathematical integrity. In order for abstraction to take place, the learner must be able to relate to the story. In order for it to foster the mathematical concepts we are interested in, these need to be the moral, or consequence of this story, not artificially grafted on top of standard mathematical pedagogical rituals.

  ['.4375' Is Half of, '.875' Is Half of, '1.75' Is Half of, '3.5' This Number]. Then, the robot proudly prints: 3. Joe999: Conclusion: You are halving the number you halved before. I have shown this in this box. Good sequence though Yish (^_^).

  This is the real graph that was produced by the cumulate total of the halving-a-number robot. it looks like the top of my graph but I made the fatal mistake of thinking it started at zero. I also said it wouldn't go over 100, which was very wrong. [Sodapop embeds function graph here]

	1. Sodapop:	This is my prediction of what will happen. [Sodapop embeds prediction graph here]
	2. Sodapop:
	3. Sodapop:	After lengthy research and a detailed experiment, I have concluded that if the primary source
		was an integer between 99 and 101 (not including those numbers) that the cumulative total can
		never go above 200. This is because if you have 0.1 and you double it and add it together you
		will get 0.15 so every time you do this you will get another number after the decimal place. So
		you will constantly get more numbers after the decimal place, but the numbers closest to the
		decimal place will not be getting any larger.

Acknowledgement

We thank Candia Morgan and the anonymous reviewers for their insightful comments. We acknowledge the support of the European Union, Grant # IST-2001-32200, directed by Celia Hoyles & Richard Noss. http://www.weblabs.eu.com


Yvan Peter

Thomas Vantroys

Eric Leprêtre

Enabling Mobile Collaborative Learning through Multichannel Interactions

Keywords: M-learning applications, mobile blog, multichannel learning services, VoiceXML interactions. I

The work presented here shows an architecture to integrate multiple communication channels for a simple communication tool: a weblog. The motivation for this work is to enable learners to access learning services regardless of their situation. Indeed, in some cases the access to these services is quite hard because people are on the move or don't easily have access to an Internet connection. This article presents the different elements that fit into the architecture which lay the path for a richer mutichannel learning environment based on Service Oriented Architecture.

INTRODUCTION

Computer Supported Collaborative Work has been a matter of research for a long time as well has its use in the learning domain with Computer Supported Collaborative Learning. One of the usual practices is to use project based learning as a mean to learn a subject matter as well as project management know-how. The project work can be supported by software systems like the Fle3 environment [START_REF] Leinonen | Learning with collaborative software -a guide to fle3[END_REF]. However, these kinds of environments are Internet-based and cannot support students and tutors when they are away from an Internet connection. On the other hand, mobile technologies have made progresses and almost every student possesses a mobile phone and probably soon a smartphone with enhanced capabilities. This has permitted the development of the mobile learning field of research which tries to enable the use of mobile technologies for learning activities [2]. This article presents the architecture we have designed to enable multichannel interaction with a collaboration system. In the first section, we present a possible scenario to show the capabilities of the system and collaboration features. The second section presents our solution to integrate the different channels. In the third section, we review existing related work. In the conclusion, we present the on-going experimentation and the future experimentations to assess the proposed system as well as the future developments.

II. SCENARIO

In this scenario, a blog is used as a communication mean to enable students to share material and information in the course of a project. Students are supposed to post project related documents, summaries of the face to face meetings both between themselves and with the tutor, keep track of the meeting dates and status of the project. For this, the blog is organised with predefined categories: documents, meeting minutes, etc. Tutors can also post contributions to the project blog and especially add comments to the students' contributions considering for example the project management or the respect of the guidelines. All these interactions will mostly happen through traditional web interfaces. However, this is not always so easy because for instance of the difficult access to the Internet during internship periods. Having access to another interaction channel may also just be a convenient alternative to the traditional web. Based on such situation, one can then support the following scenario: Cathy works on her second semester project about the preparation of an art exposition. She has just finished writing letters to possible supporters of the event. Being a milestone in the project, Cathy wants the project manager and the other students to know about it. Since she is at home and does not have an Internet connection, she picks up her phone and calls the voice server. After having identified herself with the server, she chooses to post a contribution and then she chooses the category "project management" among the ones proposed by the server. Upon a prompt from the voice server, she records the fact that the letters are ready to send. The server confirms that the contribution has been posted on the blog and Cathy hangs up. While posting the contribution, the system also sends a notification to the project manager by mail and to the tutor by SMS according to their preferences. Mark, the tutor receives the SMS while commuting. Because he thinks the project may be late, he is eager to know what project management news has been posted. He calls the voice server and identifies himself. He chooses to listen to the new contribution under the project management category. Having heard that the letters are ready to send, he decides to make a comment to this contribution to tell the students that they have to make a phone contact one week after the letters are sent. The following day, Cathy uses a computer at the university to upload the letters in the documents category. She discovers that Mike has posted a comment on her contribution and takes note of his advice. This scenario relies on the capacity of the system to handle multiple channels to interact with the users so as to IMCL2008 Conference 16-18 April 2008, Amman, Jordan

The 3 rd International Conference on Mobile and Computer Aided Learning, IMCL2008, www.imcl-conference.org 2 enhance the collaboration. In the sequel, we will give the details of the architecture we have set up to support this.

III. ARCHITECTURE Our objective is to permit the use of different channels to interact with services that support learning activities and collaboration. Towards this end, we have concentrated our effort in this first step in the introduction of the channels for a sample service which is a blog. In the next section we will present the current architecture which will be used for the first experimentations.

A. The Mobile Blog

Fig. 1 presents the global architecture of the mobile platform. The interactive voice server is the entry point for the voice interaction it is based on the App-Line product and relies on the VoiceXML standard [3] to define the vocal interactions. Voice interactions as well as SMS/MMS and traditional web are handled by an intermediation server that will provide ad hoc user interactions to the services.

1) Interacting with the Blog

Blog servers offer a variety of APIs to interact with them. Historically, these APIs are: Blogger, MetaWeblog 0 [START_REF] Winer | Rfc: Metaweblog api[END_REF] and Atom [5]. MetaWeblog is an evolution of the Blogger API which is now deprecated. It is based on XML-RPC.

Atom is the rising standard for web publishing and uses REST 0 [6] rather than XML-RPC or SOAP. Since MetaWeblog is still the most represented API at the moment, we concentrated on this despite the potential of Atom. The MetaWeblog API offers the following functions to the clients:

• user authentication;

• editing, adding and removing posts;

• retrieving recent posts;

• retrieving user related information and her/his owned blogs; • retrieving existing categories for posting; • editing the presentation template for a given blog; • uploading binary files (sound, photos, video, etc).

Based on this API, we can integrate the blog software as a service in a larger system and we have the opportunity to develop ad hoc clients corresponding to the channels we would like to introduce.

2

) Voice Interaction Design

The voice interaction application is a java web application based on servlet and JSP pages but the language used for the design of the user interaction is VoiceXML. Based on the interactions with the user, the web application then interacts with the blog server. Fig. 2 presents an excerpt from a JSP page containing a form to post a comment to a given post. The comment is recorded by the voice server. It is then replayed to the user before being submitted.

Fig. 1: Global architecture for the mobile blog

The submission activates a servlet (AddCommentServlet) which will retrieve the sound file on the voice server and interact with the blog server to upload the file as a comment to the previously selected blog entry.

Fig. 2: VoiceXML interaction to record a comment to a blog post

3) Channels and Services Integration

The integration of the different channels and services to support collaboration are done through an integration layer in the spirit of the Service Oriented Architecture. Fig. 3 presents the services that are already integrated to support the interaction with the blog server either to publish material or to get notifications of modifications of the blog. Depending on the channel and the type of interaction (post an entry, make a comment, etc) a different process may be started that will orchestrate the needed services. These processes are modeled using the BPEL4WS language [7].

Fig. 3: Channels and services integration

Here is a sample process following the submission of a contribution through the voice server:

• After the recorded contribution has been validated by the user, the sound file is sent to an Automatic Speech Recognition (ASR) service to convert it to text. • The corresponding text file is posted to the weblog using the XML-RPC API. • For the registered people a notification is sent either by email or using an external web service to send SMS.

IV. RELATED WORK The use of blogs to support learning can be found in some works. However they are usually individual and used as a mean for the student to reflect on their practices or on a subject matter [8] [9]. Mobility is usually not considered with the notable exception of the Ramble project that aimed at offering a mobile access to the blog [10]. However, in this work mobility is only supported in the sense that blog post can be authored offline on a PDA and published later on when an Internet connection is available. \cite{Balasundaram:2007} present a questionanswering learning scenario based on SMS which is an interesting alternative to traditional web based tests. However, this is an ad hoc solution and the focus is not on the diversity of interaction channels to a classical software system.

Outside of the learning field, one can find other works on mobile blogs like [12] [13]. The former proposes to enrich a photo blog by the use of external services that for example enhance the photo quality or try to recognise what is on the photo so as to annotate automatically with keywords or with related information the blog post. The latter combines SMS/MMS, WAP and Instant Messaging to post to a blog, to get a notification of new material posted or to retrieve the blog content. These two works have similarities with ours, one because it combines different services to provide new features, the other because it offers multiple channels to interact with the blog.

V. CONCLUSION In this article, we have presented the architecture we have set up to combine different channels to interact with a blog server : Web, SMS/MMS and voice. The goal is to provide enhanced access to the blog in the scope of project based learning activities. Different features are offered by the system by the orchestration of different services like Automatic Speech Recognition, Text to Speech, SMS notification, etc. In the future, the blog itself will become a service among others as we integrate new services such as a shared calendar that will offer a richer environment for project management and collaboration. In the meantime, we have to assess the proposed architecture through experimentations. A first experimentation is running that involves student during internship. The blog is used as a mean of communication and supervision by the tutor. There is no strong collaboration in this case, but the experiment will assess the robustness of the system and its usability. We will also start to see in which context the different channels are used. Based on this experiment, a second experimentation will be launched on projects within different diploma at the licence and master level in different disciplines. This second experience will be more focused on the enhancement of the collaboration.

ACKNOWLEDGMENT

This work is supported in part by the ANR project p-LearNet and the CAPES-COFECUB project AdContext (057/07).

AUTHORS

Y. Peter is with the Laboratoire d'Informatique Fondamentale de Lille -Université de Lille 1 -France (email: yvan.peter@univ-lille1.fr).

T. Vantroys., is with the Laboratoire d'Informatique

Fondamentale de Lille -Université de Lille 1 -France (email: Thomas.vantroys@univ-lille1.fr).

E. Leprêtre is with the Laboratoire d'Informatique Fondamentale de Lille -Université de Lille 1 -France (email: eric.lepretre@univ-lille1.fr).


teaching and research institutions in France or abroad, or from public or private research centers.

K22989

Glutamine: Biochemistry, Physiology, and Clinical Applications describes the different functions of glutamine (Gln) in animals and humans. Gln is both a nutrient and a signaling molecule, and its functions go beyond those of a simple metabolic fuel or protein precursor. This book has gathered together, in an unbiased and critical manner, all the available evidence and research on Gln including pathology (neurological diseases, intestinal diseases, critical illness, and cancer), physiology (successful aging), catabolic states, immunity, and exercise. Special attention is given to the potential bene t of Gln in states of insulin resistance and the role of Gln as a "conditionally essential" amino acid.

Features

• Promotes the signaling role of Gln in autophagy, which is an emerging concept in aging due to the fact that its increase can favor longevity. • Considers how a high concentration of Gln and its accumulation in plasma and in the brain can induce toxicity and lead to severe central nervous system diseases. • Demonstrates how Gln supplementation is bene cial for the recovery of intestinal mucosal integrity and for intestinal diseases and aging. • Discusses why Gln supplementation in catabolic states is only warranted in the event of hypoglutaminemia and the absence of renal or hepatic failure. • Highlights how Gln, as a promising biomarker or even as a therapeutic target in cancer, could have an important role in effective anticancer strategies. • Includes future directions of Gln research.

The contributors are either pioneers or experts in the area of Gln from all around the globe, including Australia, Brazil, Canada, China, Europe, and the United States. This book is a valuable source of information for nutrition scientists, medical doctors, sports scientists, food scientists, dietitians, and anyone interested in nutrition. It is also a valuable resource for students in these elds and will be an important addition to university libraries.

Glutamine Biochemistry, Physiology, and Clinical Applications

  T A M I N E Meynial-Denis


Implication of the UPS on muscle wasting in humans

  Adapted fromPolge et al. Front. Physiol., 2015 Targets of the UPS during muscle wastingThe UPS controls all the key processes for the development of the atrophying

  MuRF1 and MAFbx are overexpressed during Acute Kidney Injury in rats and their expression levels are correlated to the severity of kidney injury Aniort et al, Int. J. Biochem. Cell Biol. 2016Acute kidney injury (gentamicin) induces a moderate atrophy (-17%) in phasic musclesImplication of the UPS on muscle wasting following chronic kidney disease in humansProteolysis induction?UPS involvement?Long lasting induction of atrogenes?Common biomarkers with more aggressive conditions/pathologies? Human vs. rodent biomarkers ?Implication of the UPS on muscle wasting following chronic kidney disease in humans: the PROMETHE cohort and 19S RC) is not a good predictor of muscle atrophy for long term UPS induction

The "Atrophy-related genes "atrogenes" MuRF1 and/or MAFbx Catabolic situa-ons

	E3 ligase		Targeted protein
			or pathway	Ubiquitin chain type	Disease
	FANCL DDB2		FANCD2, FANC1 Chromatin	Atrogenes monoUb monoUb	Condi7ons	Fanconi anemia Xeroderma pigmentosum
	Cbl family	RTKs	monoUb		Cancer
	Nedd4 Rabex-5 HDM2	Non pathological states PTEN, α-synuclein monoUb, Lys63, polyUb Bed rest Ras monoUb Immobiliza7on / unweigh7ng Cowden syndrome, Parkinson Cancer p53 Lys48 Cancer
	APC/C10		Cyclin-CDK	Lys48	Aging	Genomic instability
	SOCS1/3		IRS2	Lys48		Metabolic syndrome
	MG53		IR, IRS1	Lys48		Metabolic syndrome
	pVHL15		HIF	Lys48	COPD	Von Hippel Lindau
	IAPs Rnf168 TRAF6 Itch, IAPs Parkin	NIK Pathological and injury states Histones TRAF6, NEMO, huntingtin RIP2 Mitochondrial outer membrane proteins	Lys48 Lys63, polyUb Lys63, polyUb Lys63, polyUb Lys63, polyUb	Spinal cord transec7on Multiple myeloma Cancer, RIDDLE syndrome Spinal muscle atrophy Inflammatory disease, Smoking Huntington's disease Myosi7s Crohn's disease Sta7ns Parkinson's disease Cancer
	CHIP, Parkin Huntingtin,	Lys63, polyUb	Pulmonary arterial hypertension Huntington's disease,
			β-amyloid, tau		Knee arthroplasty Alzheimer's disease
	BRCA1		BRCA1	Atypical polyUb		Breast and ovarian cancer
	LUBAC		NEMO	Linear polyUb		Autoinflammation, muscular
					amylopectinosis, bacterial infections

The "Atrophy-related genes "atrogenes" (Unweighting -rat soleus muscle)Polge & Taillandier, Int. J. Biochem. Cell Biol., 2016 Some Atrogenes are strictly restricted to the atrophying program Some Atrogenes are still recruited after 7 days of recovery -Proteasome subunits -Ub -Specific ubiquitinating enzymesTaillandier et al., Int. J. Biochem. Cell Biol. 2003 ; Polge & Taillandier, Int. J. Biochem. Cell Biol., 2016

Acknowledgements

Perspectives

• Including other proteoly-c actors: --> beler isola-on of specific popula-ons?

• Using more pa-ents/other cohorts for strengthening the conclusions

• Applica-on to other pathologies

• Finding biomarkers in more accessible compartments (e.g. blood)

• Comple-ng the proteomic analysis of soluble proteins

• Iden-fica-on of UPS substrates common to the two pathologies Purifica-on of Ub--conjugates using an in--house affinity matrix followed by mass


Nutritionnal ,  Energy (9 kcal/g), digestibility of Triglycerides 98 %  Essential Fatty acids (acide linoleic acid ω6 et α-linolenic acid ω3) 46 Impaired by aging, alcohol, nutrient deficiencies, trans FA, elevated cholesterol

→ oleochemical market: high demand for oleochemistry in 2030, 30 Millions of tons, rapidly increasing market Potentially interesting sources that have to be developped: crambs, camelina, calendula, lunaire, euphorbia, lesquerella : all with specific FA of interest but with low yield => improvement necessary to be come good sources.

→ cosmetics market: rapidly increasing, lipids and skins have in common lots of componenents, application in oral or dermatologic applications. ω6membranar fluidity, barrier properties ω3 anti-inflam, main membranar constituants, ω9 emollient Use and developments of lots of esters in formulation (adjustement of HLB, waxes…)

22

Few socio-economic data Consummed in exces, omega-6 FA can : -impair the beneficial health effects of oméga-3, notably with regards to CV protection.

-Induce pains and inflammatory illnessess such as asthma and arthritis.

-++ present in modern food diet: maize, sunflower, soya, carthame, grapeseed oils, etc.

-Minimal biological need in LA ~ 2 % TEI, which corresponds roughly to 4,4 g/j for a total intake of 2000 Kcal/j. ANSES => ANC à 4 % of TEI.

Gamma-linolenic acid (GLA, C18:3 cis 6,9,12) not to be confused with ALA (C18:3 cis 9,12,15), is synthesized by body from LA (C18:2 cis 9,12) under the action of Delta-6 desaturase.

-But conversion can get LIMITED by: excessive consumptin of cholesterol and of « bad fat » (trans, saturated, etc.), alcohol, aging, diabetes… -Food product, direct source of GLA: borage oil (24 %), evening primrose oil (8 %), blackcurrent oil (18 % d'AGL) and spiruline.

Arachidonic acid (AA, C20:4, w6 -males and females >14, 15 µg of alpha-tocopherol per day.

-Expressed in the most active and used form => alpha-tocopherol. 1 mg alpha-tocopherol=1.5 International Units (IU).  Transformation into methyl esters



  Generality about lipids /oils  Few socio-economics data 2. LIPIDS IN ALIMENTATION / NUTRITIONNAL PART 3. BIOCHEMISTRY OF VEGETABLE LIPIDS  Composition of vegetable lipids  Analyses of lipids  Oxidation of lipids 4. TECHNOLOGY OF VEGETABLE LIPIDS  Processing of oils  Chemical and enzymatic modifications of lipids  Processing margarines 5. Few oil monographies 6. Conclusions 2 Raw oil: oil just after extraction whatever the obtention process Virgin oil: oil obtained from selected premium raw matter with specific extraction process: exclusively mechanical, without solvant, clarification with physical means only, no post-extraction chemical or physical refining process allowed. Extra virgin AI <0.8 (g/100 g), PI <20 Refined oil is obtained by pressure and /or solvant extraction , followed by alcaline reffinery, decoloration, desodorisation from a raw oil Hydrogenated oil / partially hydrogenated oil is obtained from refined oil further hydrogenated 12 NEW LABELLING RULE IN UE  13 décembre 2014, AAI under reglement (UE) n° 1169/2011 of european parliament and council of 25 october 2011 about information to consummers about food products => Mandatory to declare precisely the botanic origin of refined vegetable oil and (for instance, colza oil, palm oil, sunflower oil and not simply vegetable oil); Elaeis guineensis 80-85 % of annual worldwide oil and fat production is for human food, 5-6 % for animal feeding, ~ 14 %, 15-17 millions t for non food industrial (Gunstone and Hamilton 2001) 85 % of global production is vegetal, 15 % animal Most important increase for palm = roughly 30 % of vegetable oil production, soya (28%), colza (15%) and sunflower (9%). Other production representent around 20% of market. 20 Few socio-economic data  Applications of lipids and fats (ITERG, 2015) :  75 % in human food application Lipides in frequently consummed food ~1/3 visible (oil, emulsion), 2/3 are hidden (constitutive lipids of food (for instance in meat tissues 4-19%) + addition in transformed IAA food products for instance panification, biscuits). + High VA niche food products: dietetics, supplements Lipids are central in public health policies : cardiovascular disease, 1 cause of death globally: more people die annually from CVDs than from any other cause (WHO 2015), recommended dietary allowance (RDA) 2010 LA/ALA = 4 21 Few socio-economic data  Applications of lipids and fat (ITERG, 2015) :  25 % of oils and fat for non food uses:

  , fruits …) 85 % Animals land (mammals, lards…) or marine 15 % Insects Who consume / product these oils and fats ? Few socio-economic data Main consumers worldwide 2012 Rapport PROLEA 2012-2013 de la production à la consommation . of raw oils and 2 Mt refined oils. acids  Precursors of prostaglandins, thromboxans, prostacycline, leucotrienes (= eicosanoids)  Membranar constituants  Vector of vitamines (A, D, E, K)  phytosterols, antioxydants Organoleptic  Texture  Arome carrier  Arome precursor Technological  heat transfer fluid  Surface treatment Main part played by oil in food ? Nutritionnal ,  Energy ? (9 kcal/g), digestibility of Triglycerides 98 % Respective contribution of human gastric and pancreatic lipase to dietary TAG digestion (Bakala et al., Therapeutic deivery, 2012) Size and traficking of different lipoprotein particles Relation between size and density of different lipoproteins Good cholesterol / uptake towards liver remnants  Energy (9 kcal/g), digestibility of Triglycerides 98 %  Essential Fatty acids (linoleic acid LA ω6 et α-linolenic acid ALA ω3) 44 These two fatty acids (FA) are said essential car human can not synthesize them and they have to be brought by diet Omega-6 Polyinsaturated oils, flax, corn, safflower Omega-3 Balck current (15%), flax (85 %) These two fatty acids (FA) are said essential car human can not synthesize them and they have to be brought by diet Omega-6 Polyinsaturated oils, flax, corn, safflower Omega-3 Balck current (15%), flax (85 %), hemp, colza, soya These FA are involved in several central physiological processus: Constitution and integrity of cellular membrane, good cardiovascular functions, cerebral functions, inflammatory and hormonal balances… Respect ω6/ω3 < 5 -ANSES -saisine no 2006-SA-0359birth to highly unsaturated FA and cellular messangers eicosanoïds Postive effects -composition of cell membranes -Several biochemical process of organism : regulation of blodd pressure, vessels elasticity, immune and anti-inflammatory reactions, blood platelets agregation. birth to highly unsaturated FA and cellular messangers eicosanoïds Potential health effects (ANSES, WHO) -Compulsory for development and functions of retina, brain and nervous system => specific requirement during gestation, breastfeeding and infancy --CV effects, can contribute to lower BP in hypertentive, decrease TAG in blood, in people presenting CV pathology can reduce morbidity and mortality WHEN COMBINED with balanced diet/ physical activity EPA/DHA: -cerebral functions and aging. Positive effect on maintaining mental health (depression, demence, Alzheimer disease) -Prevention of age-related macular degeneration (AMD) Omega-6 Play an important part in good funtionning of nervous, cardiovascular and immunitary systems and nerveux, are central in allergic reactions, inflammatory reactions and healing processes.

FA

  12 months 10 µg cholecalciferol (vitamin D3) -From 12 months to 50 y =15 µg -20 µg = 800 International Units (IU), recommendation for maintenance of healthy bone for adults >50 -Special needs: exclusively breast-fed infants: Human milk 25 IU /L, Dark Skin, Covered and protected skin, illnesses (Fat malabsorption syndromes, inflammatory bowel disease (IBD)protecting vitamins A and C, red blood cells, and essential fatty acids from destruction Recommended Dietary Allowance (RDA):



  Concrete oil. Solid at ambiant temperature since rich in SFA • Palmitic acid dominant : group atherogenic in exces with lauric and myristic ≤ 8 % TEI (total satured ≤ 12 % TEI) • Only 11 % of palmitic in central sn-2 position, less aborbed in external position  Increase of cholesterol LDL (less than coprah oil) and less of HDL  Moderate effect on plasma lipids can be explained by minor compounds : E vitamin E, carotenoïdes, phytosterols, phenolic compounds. can be generated when in contact with air -Linked to FA peroxydation that get polymerized or broken into aldehydes, cetones or acids coexist: systematic names often replaced by common names. 2 ways of numbering, one systematic (chemist) and the other often used by dieteticians/ biologists helps separated FA in series First indicate number of carbons on fatty acid, then indicate number of unsaturation (double bond) (Δ or ω), then their position and configurations (cis ou trans).

history of lipid nutritionnal recommandations Brief history of lipid nutritionnal recommandations

	Fatty acids	RDA (% TEI)		% TFA
		LA (C18:2, ω6)	4 %	10-12 %
	essential	ALA (C18:3, ω3) Docosahexaenoic acid, DHA (C22:6 ω3)	1 % 250 mg	2.5-3 %
		Eicosapentaenoic acid, EPA (C20:5 ω3)	250 mg
	Non essential	Lauric + myristic + palmitic FA	≤ 8 %	20-

). Present in PL (PE, PC, PI) in liver, muscle, brains. Key inflamatory intermediate, vaso-dilator. Egg yolk is a direct source 1957. The 'seven country studies'.

Keys et al. JAMA. 164:1912-1919

. → apparent link between consumption of saturated fat, cholesterol and CV Brief

23 % Total saturated FA ≤12 % 30-34 % Oleic

FA (C18:1, ω9) 15-20 % 38-50 % 2010. Re-assesment of RDA for FA / ANSES

Nutritionnal,

% 1 %

Nutritionnal ,  Energy (9 kcal/g), digestibility of Triglycerides 98 %  Essential Fatty acids (linoleic acid LA ω6 et α-linolenic acid ALA ω3)

Enzymatic lipolysis of triacylglycerols by digestive lipases

Small classification

Main part played by oil in food ?

Cholesterol and cholesterol esters

Cholesterol is an extremely important biological molecule that has roles in membrane structure as well as being a precursor for the synthesis of the steroid hormones, the bile acids, and vitamin D DHCR7: 7dehydrocholesterol reductase.

7-deshydrocholesterol

Vitamine D Steroids

Gonads adrenals +++ Biliary salts De novo biosynsthesis, 2/3 of total (liver and intestine), 1/3 dietary Healthy adults synthesize cholesterol at a rate of ~1g/day, consumption 0.3 g/day. A relatively constant level of cholesterol in the blood (150-200 mg/dL) is maintained primarily by controlling the level of de novo synthesis.

3 distinct mechanisms of regulation: 1. Regulation of Hydroxyméthylglutaryl-CoA réductase activity and levels (oxydoreductase statine target) 2. Regulation of excess intracellular free cholesterol through the activity of sterol O-acyltransferases, SOAT1 and SOAT2 3. Regulation of plasma cholesterol levels via LDL receptormediated uptake and HDL-mediated reverse transport (to liver). 66

Cholesterol and cholesterol esters

Main part played by oil in food ? Recommended Dietary Allowance (RDA): 900 µg/ day for adult males and 700 mcg/day for adult females, expressed µg of retinol activity equivalents (RAE). => body converts only a portion of betacarotene to retinol. 1 RAE = 1 µg of retinol =12 µg betacarotene.

Vitamin K:

Main functions: -Blood clotting, naturally produced by the bacteria in the intestines, -bone health -post-traductional modification of proteins for blood, bones, and kidneys.

Recommended Dietary Allowance (RDA):

-males and females >18, resp. 120 and 90 µg of Vit K -Highly dependent on age, 0-6 mo 2 µg, 6-12 mo 2.5 µg

NORMALIZED METHOD

Acidity is expressed in % oleic acid


Dr Pr A Avignon

L Téot

Dr S Ehrler

Dr M Berthel

Joffre Cd

Dr S Schuldiner

C Rémy

Nîmes Joffre

Dr N Jourdan

Dr S Clavel

C Denisot

Le Creusot

Dr S Doublet

Dr F Fluieraru

Pr A Gaillard

Sultan

Joffre Cd Atelier

Dr J Pochic

M Latour Pédicurie

Dr E Antoine Melon

Comment faire un prélèvement bactériologique ?

Auditorium Pasteur Atelier n°6 Discussions pluridisciplinaires autour de cas cliniques, F. Doublet, Dr S. Fluieraru, Dr F. Gaillard, Pr A. Sultan, Montpellier

  Atelier n°7 (nombre de places limité) Amputation mineure, cas cliniques, rééducation et appareillages : discussions autour de cas cliniques, Dr S.Ehrler, StrasbourgJoffre bAtelier n°8 (nombre de places limité) Comment faire un prélèvement bactériologique ? Dr S. Schuldiner, C. Rémy, Nîmes Le médecin généraliste, un acteur clé au coeur de la prévention de l'amputation Modérateurs : Pr P. Lambert, Pr A. Sultan 18.00 Point de vue de l'association de patients, F. Coste, Gestion de l'insuline, cas cliniques, Dr V. Taillard, Nîmes 09.10 Place de l'infirmier dans l'insulinothérapie, F. Jourdan, N. Amphoux, Montpellier Joffre CD Atelier n°10 (nombre de places limité) Amputation mineure, cas cliniques, rééducation et appareillages : discussions autour de cas cliniques, Dr S. Ehrler, Strasbourg Joffre a Atelier n°11 (nombre de places limité) Comment mettre en décharge un patient porteur de troubles trophiques ? Dr S. Clavel, C. Denisot, Le Creusot Auditorium Pasteur 10.00-11.30 Plénière : Chirurgie et pied diabétique 10.00 Gestes d'urgence en chirurgie du pied diabétique, Dr L. Téot, Montpellier 10.20 L'artérite chez le patient 10.40 Correction chirurgicale des troubles morphostatiques de l'avant 11.00 Reconstruction tégumentaire du pied diabétique, Dr C. Herlin, Montpellier 11.30-13.00 Plénière : Infectiologie -11.30 Diagnostiquer l'os infecté, Dr A. Piaggesi, Pise Italie 12.15 Microbiote du pied diabétique, impact sur la prise en charge, Pr JP Lavigne, Nîmes 12.35 Antibiothérapie : Quand ? Lesquels ? Pour quelle durée ? Pr E. Sen en charge de l'ulcère du pied diabétique par le médecin généraliste dans quatre pays européens, Dr J. Martini, Toulouse 14.10 Parcours de soin des patients diabétiques avec une plaie de pied avant l'arrivée en centre expert, Dr C. Amouyal 14.20 Laser et oscillation profonde dans le programme de neurorééducation du pied diabétique de type Charcot, Dr I. Koleva 14.30 Faisabilité de la biopsie osseuse au lit dans un service de diabétologie pour la prise en charge des plaies de pieds sus 14.40 Les amputations fonctionnelles du pied chez le diabétique, Dr FGestes d'urgence en chirurgie du pied diabétique, Dr L. Téot, Montpellier patient diabétique : quand et comment revasculariser ? Correction chirurgicale des troubles morphostatiques de l'avant-pied, Dr N. Cellier, Nîmes Reconstruction tégumentaire du pied diabétique, Dr C. Herlin, Montpellier -Session Jean-Louis Richard Modérateurs : Dr J. Martini, Pr A. Sotto Diagnostiquer l'os infecté, Dr A. Piaggesi, Pise Italie Microbiote du pied diabétique, impact sur la prise en charge, Pr JP Lavigne, Nîmes Antibiothérapie : Quand ? Lesquels ? Pour quelle durée ? Pr E. Senneville, Tourcoing Pause repas, visite des stands Modérateurs : Pr. A. Avignon, Dr L. Téot Prise en charge de l'ulcère du pied diabétique par le médecin généraliste dans quatre pays européens, Dr J. Martini, Toulouse Parcours de soin des patients diabétiques avec une plaie de pied avant l'arrivée en centre expert, Dr C. Laser et oscillation profonde dans le programme de neurorééducation du pied diabétique de type Charcot, Dr I. Koleva Faisabilité de la biopsie osseuse au lit dans un service de diabétologie pour la prise en charge des plaies de pieds suspectes d'ostéite, Dr F. Feron Les amputations fonctionnelles du pied chez le diabétique, Dr F. Bonnel Etude clinique de supériorité randomisée en cross-over : traitement par pression négative + algosteril en interface vs traitement par pression négative, M. Angot nique randomisée de non-infériorité : algostéril vs la thérapie par pression négative Modérateurs : Dr il possible de prévenir le diabète de type 2 par la nutrition ? Dr A. Fardet, Clermont La prévention cardio vasculaire du diabète passe-t-elle par l'assiette ? Pr P. Darmon, Marseille Nutrition et diabète, Pr A. Avignon, Montpellier Modérateurs : Pr F. Canovas, Pr P. Alric Gestes d'urgence en chirurgie du pied diabétique, Dr L. Téot, Montpellier ? Dr JP Becquemin, Paris pied, Dr N. Cellier, Nîmes Reconstruction tégumentaire du pied diabétique, Dr C. Herlin, Montpellier ateurs : Dr J. Martini, Pr A. Sotto Microbiote du pied diabétique, impact sur la prise en charge, Pr JP Lavigne, Nîmes eville, Tourcoing ateurs : Pr. A. Avignon, Dr L. Téot Prise en charge de l'ulcère du pied diabétique par le médecin généraliste dans quatre pays européens, Parcours de soin des patients diabétiques avec une plaie de pied avant l'arrivée en centre expert, Dr C. Laser et oscillation profonde dans le programme de neurorééducation du pied diabétique de type Faisabilité de la biopsie osseuse au lit dans un service de diabétologie pour la prise en charge des over : traitement par pression négative + algosteril en té : algostéril vs la thérapie par pression négative, Dr M. Gorj Modérateurs : Dr F. Carbonnel, Pr A. Sultan par la nutrition ? Dr A. Fardet, Clermont-Ferrand elle par l'assiette ? Pr P. Darmon, Marseille


Stéphane Gaborieau

Aurélie Cendres

Céline Persillon

S Pallas

Catherine M G C Renard

OF GLYCOSIDASES FORRELEASE OF AROMAS FROM STRAWBERRY Catherine M G C Renard Opti- Misation

OPTIMISATION OF GLYCOSIDASES FORRELEASE OF AROMAS FROM STRAWBERRY GLYCOSIDES

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

OPTIMISATION OF GLYCOSIDASES FOR RELEASE OF AROMAS FROM STRAWBERRY GLYCOSIDES

Authors: Gaborieau S 1, 2 , Cendres A 1 , Persillon C 3 , Pallas S 3 , Renard MGC 2 1 Atelier du fruit, 7 rue des Pommerets, 21 600 Longvic-FRANCE 9 In fruits a portion of potentially aromatic molecules are bound to sugars, so that they are not volatile and do not contribute to aroma. Glycosidases are a promising way to release this aromatic potential in fruits, especially in strawberries, and thus offer a solution to limit addition of (synthetic) aromas in fruit products. However, these enzymes are usually sensitive to the concentration of sugars and to low pH. Fruits are therefore not the most adapted media for these enzymes. An optimization of glycosidases by enzyme engineering was therefore carried out with two main aims. The first is to increase their activity in the fruit conditions and the second is to limit side activities that may affect color and texture of fruit products. Indeed, anthocyanins in strawberries are glycosylated and the aglycones lose color rapidly, and the commercial enzyme used for glycosidic activity has also a pectinolitic activity which destroys the texture of fruit purees. The Shuffling® method was selected to decrease the sensitivity to sugars and to increase activity. After screening two new enzymes are kept, one (F1) with a low sensitivity to sugars and another (F2) with a higher specific activity. F1 lost only 27% of its activity in a sugar solution (18% of fructose, 16% of glucose and 11% of sucrose) instead of 80% for the parental enzymes, and F2's specific activity was increased by 50% compared to parental enzymes. Texture and color were not affected by the new enzymes. Different concentrations were tested for an incubation time of 90 minutes and for a temperature of 40°C (optimal temperature of engineered enzyme) to identify minimal required enzyme concentrations. Enzyme denaturation by pasteurization was also studied to ensure that the new enzymes will belong to processing aids.

2

  UMR408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Avignon University F-84000 Avignon, France 3 Proteus, 70 Allée Graham Bell, 30000 Nîmes, France