39 research outputs found
Lieb-Robinson Bounds for the Toda Lattice
We establish locality estimates, known as Lieb-Robinson bounds, for the Toda
lattice. In contrast to harmonic models, the Lieb-Robinson velocity for these
systems do depend on the initial condition. Our results also apply to the
entire Toda as well as the Kac-van Moerbeke hierarchy. Under suitable
assumptions, our methods also yield a finite velocity for certain perturbations
of these systems
Many body physics from a quantum information perspective
The quantum information approach to many body physics has been very
successful in giving new insight and novel numerical methods. In these lecture
notes we take a vertical view of the subject, starting from general concepts
and at each step delving into applications or consequences of a particular
topic. We first review some general quantum information concepts like
entanglement and entanglement measures, which leads us to entanglement area
laws. We then continue with one of the most famous examples of area-law abiding
states: matrix product states, and tensor product states in general. Of these,
we choose one example (classical superposition states) to introduce recent
developments on a novel quantum many body approach: quantum kinetic Ising
models. We conclude with a brief outlook of the field.Comment: Lectures from the Les Houches School on "Modern theories of
correlated electron systems". Improved version new references adde
Learners' perceptions of their successes and failures in foreign language learning
This is a postprint of an article whose final and definitive form has been published in the Language Learning Journal © 2004 Copyright Taylor & Francis; Language Learning Journal is available online at http://www.informaworld.comResearch into learners’ attributions for their successes and failures has received considerable attention. However very little has been carried out in the area of learning foreign languages. This study is timely in view of the current interest by the government in promoting foreign languages.
The aims of the study were (1) to investigate secondary students’ attributions for their success and failures in learning foreign languages (2) to examine the ways in which these vary according to age, gender, perceived success and specific language studied.
The sample consisted of 285 students between the ages of 11 and 16 studying French, German and Spanish in five secondary schools in the UK. A simple open questionnaire was administered by language teachers, consisting of a personal evaluation by students of their perceived level of success as learners of specific foreign languages and their attributions for success and failure in those domains.
The resulting responses were analysed by means of a grounded theory approach allowing categories to emerge from the data. The resultant categories were then tabulated according to student age, gender, and language learnt, together with level of perceived success.
Over one thousand attributional statements gave rise to 21 attributional categories for doing well and 16 categories for not doing well at language learning. A far wider range of attributions were identified than is generally shown in the research literature, six of which were most commonly called upon as reasons for both success and failure. Clear differences emerged between boys and girls, year groups, perceived success and language studied. These results and, in particular, the lack of clarity in the learners’ comments about strategy use and the lack of focus on metacognitive strategies, have important implications for policy makers and for teachers of foreign languages in UK schools. In addition there are important implications for future research in this area
Larval density, temperature and biological aspects of Chrysomya megacephala (Diptera: Calliphoridae)
The Regulatory Factor ZFHX3 Modifies Circadian Function in SCN via an at Motif-Driven Axis
We identified a dominant missense mutation in the SCN transcription factor Zfhx3, termed short circuit (Zfhx3Sci), which accelerates circadian locomotor rhythms in mice. ZFHX3 regulates transcription via direct interaction with predicted AT motifs in target genes. The mutant protein has a decreased ability to activate consensus AT motifs in vitro. Using RNA sequencing, we found minimal effects on core clock genes in Zfhx3Sci/+ SCN, whereas the expression of neuropeptides critical for SCN intercellular signaling was significantly disturbed. Moreover, mutant ZFHX3 had a decreased ability to activate AT motifs in the promoters of these neuropeptide genes. Lentiviral transduction of SCN slices showed that the ZFHX3-mediated activation of AT motifs is circadian, with decreased amplitude and robustness of these oscillations in Zfhx3Sci/+ SCN slices. In conclusion, by cloning Zfhx3Sci, we have uncovered a circadian transcriptional axis that determines the period and robustness of behavioral and SCN molecular rhythms