This paper offers an inductive, exploratory study on the role of input and individual differences in the early code-mixing of bilingual children. Drawing on data from two German-English bilingual children, aged 2–4, we use the traceback method to check whether their code-mixed utterances can be accounted for with the help of constructional patterns that can be found in their monolingual data and/or in their caregivers’ input. In addition, we apply the tracebackmethod to checkwhether the patterns used by one child can also be found in the input of the other child. Results show that patterns found in the code-mixed utterances could be traced back to the input the children receive, suggesting that children extract lexical knowledge from their environment. Additionally, tracing back patterns within each child was more successful than tracing back to the other child’s corpus, indicating that each child has their own set of patterns which depends verymuch on their individual input. As such, these findings can shed new light on the interplay of the two developing grammars in bilingual children and their individual differences.

Multiple Sequence Alignment (MSA) is a fundamental analysis method used in bioinformatics and many comparative genomic applications. The time to compute an optimal MSA grows exponentially with respect to the number of sequences. Consequently, producing timely results on large problems requires more efficient algorithms and the use of parallel computing resources. Reconfigurable computing hardware provides one approach to the acceleration of biological sequence alignment. Other acceleration methods typically encounter scaling problems that arise from the overhead of inter-process communication and from the lack of parallelism. Reconfigurable computing allows a greater scale of parallelism with many custom processing elements that have a low-overhead interconnect. The proposed parallel algorithms and architecture accelerate the most computationally demanding portions of MSA. An overall speedup of up to 150 has been demonstrated on a large data set when compared to a single processor. The reduced runtime for MSA allows researchers to solve the larger problems that confront biologists today.

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Les associations locales jeunes (YMG ; young moving group) sont des groupes d’étoiles jeunes, principalement des étoiles naines M, partageant une cinématique commune, situées dans le voisinage solaire et formées à la même époque lors de l’effondrement d’un nuage moléculaire unique à chaque association. Ce sont des laboratoires idéals pour l’étude des dernières étapes de la formation stellaire et l’imagerie directe d’exoplanètes. L’association β Pictoris (βPMG ; β Pictoris moving group) est l’une des plus jeunes et des plus rapprochées, mais son âge demeure incertain : les méthodes des isochrones et de la limite d’épuisement du lithium (LDB ; lithium depletion boundary ; 21−24 Ma) sont incohérentes avec la méthode du retracement à l’origine (11−13 Ma), consistant à retracer le parcours des étoiles membres jusqu’à l’époque où l’étendue de l’association était minimale, soit l’époque de la formation stellaire. Cette étude présente une nouvelle méthode numérique, appelée Traceback, permettant de trouver un âge cinématique pour une association par retracement à l’origine avec les données du catalogue Gaia Data Release 2 (DR2). Sa précision théorique maximale est calculée et deux biais sont caractérisés : un biais dû aux erreurs de mesure (∼ −4,5 Ma) et un biais ∆v_r, grav = 0,5 km/s sur les mesures de vitesse radiale (v_r) dû au décalage vers le rouge gravitationnel (∼ −1,8 Ma). En appliquant cette méthode à un échantillon de 46 membres validés de l’association β Pictoris, un âge cinématique corrigé de 17−19 Ma, compatible avec les âges obtenus avec les méthodes des isochrones et de la LDB, est trouvé en minimisant la déviation médiane absolue (MAD ; median absolute deviation), une mesure de l’étendue de l’association résiliente aux données déviantes, et la covariance X-U entre les positions X et les vitesses U des étoiles membres. De plus, on montre que l’usage d’un arbre couvrant de poids minimal (MST ; minimum spanning tree) n’apporte aucun avantage. / Young moving groups (YMGs) are associations of young stars, mainly M dwarfs, that share a common kinematics, located in the solar neighbourhood and formed at the same epoch by the collapse of a molecular cloud that is unique to every association. They are ideal laboratories for the study of the last steps of stellar formation and the direct imaging of exoplanets. The β Pictoris moving group (βPMG) is one of the youngest and closest YMGs, although its age remains uncertain: ages found using isochrones or the lithium depletion boundary (LDB; 21 − 24 Myr) are inconsistent with traceback ages (11 − 13 Myr), found by tracing back the trajectories of member stars up to the epoch when the size of the YMG was minimal, which coincides with the epoch of stellar formation. This study presents a new numerical method, called Traceback, capable of finding a kinematic age for a YMG by traceback with data from the Gaia Data Release 2 (DR2) catalog. Its maximal theoretical precision is calculated and two important biases are characterized: a bias due to measurement errors (∼ −4.5 Myr) and a ∆v_r, grav = 0.5 km/s bias on radial velocity (v_r ; vitesse radiale) measurements due to gravitational redshift (∼ −1.8 Myr). When this method is applied to a sample of 46 validated members of βPMG, a corrected kinematic age of 17 − 19 Myr, in agreement with isochrones and LDB ages, is found by minimizing the median absolute deviation (MAD), a measure of the size of the association that is robust against outliers in the data, and the X-U covariance between the X positions and the U velocities of member stars. Furthermore, the use of a minimum spanning tree (MST) is shown not to be advantageous.