Discretization strategies for computing Conley indices and Morse decompositions of flows

Conley indices and Morse decompositions of flows can be found by using algorithms which rigorously analyze discrete dynamical systems. This usually involves integrating a time discretization of the flow using interval arithmetic. We compare the old idea of fixing a time step as a parameters to a time step continuously varying in phase space. We present an example where this second strategy necessarily yields better numerical outputs and prove that our outputs yield a valid Morse decomposition of the given flow

Telerehabilitation for aphasia – protocol of a pragmatic, exploratory, pilot randomized controlled trial

Background The Cochrane review on the effectiveness of speech and language therapy for aphasia following stroke suggests intensity of therapy is a key predictor for outcome. Current aphasia services cannot provide intervention at the intensity observed within trial contexts because of resource limitations. Telerehabilitation could widen access to speech-language pathologists (SLPs) in geographically remote contexts and reduce the time spent on travel by the therapist and patient. The current academic literature within this field is in its infancy, with few trials of speech and language therapy (SLT) delivered by videoconference. Our pilot randomized controlled trial (RCT) will explore feasibility aspects and effectiveness of telerehabilitation for aphasia in addition to standard SLT. Method/design Our study is a pragmatic, exploratory, pilot randomized controlled trial, where participants will be randomized to a telerehabilitation group or a control group. Both groups receive standard SLT (usual care) but the telerehabilitation group receives an additional 5 h of telerehabilitation per week over 4 weeks through videoconference. This additional telerehabilitation focuses on spoken language with an emphasis on word naming. We aim to include 40 patients in each group, with inclusion criteria being aphasia any time post stroke. Participants will be assessed blindly at pre-randomization (baseline), and 4 weeks and 4 months after randomization. The primary endpoint is naming ability 3 months after the completed intervention, measured by the Norwegian Basic Aphasia Assessment (NGA) naming subtest. Secondary endpoints include other subtests of the NGA, the VAST (Verb and Sentence Test) subtest sentence production, Communicative Effectiveness Index (CETI) and the Stroke and Aphasia Quality of Life scale (SAQOL-39). Experiences of patients and SLPs with telerehabilitation are assessed using questionnaires and semi-structured interviews. Statistical between group comparisons will be in line with an intention-to-treat analysis. Discussion This pilot RCT of intensive language training by videoconference will contribute new scientific evidence to the field of aphasia telerehabilitation. Here, we describe our trial which will explore the feasibility of telerehabilitation for aphasia as an intervention, our choice of primary and secondary outcome measures and proposed analyses. Our trial will provide information for the development and delivery of future definitive RCTs. Trial registration ClinicalTrials.gov, ID: NCT02768922 . Registered on 11 May 2016. Last updated on 17 November 2017

Tell Me and I Forget, Involve Me and I Learn: Design and Evaluation of a Multimodal Conversational Agent for Supporting Distance Learning

The COVID-19 pandemic has shifted children’s learning routines from schools to their own homes, necessitating learning support solutions. This paper reports on a design science research project that combines augmented reality with a conversational agent to assist schoolchildren in learning complex subjects by providing verbal descriptions and interactive animations. Drawing on the theoretical foundations of multimedia learning, we derive three design principles to resolve seven issues associated with distance learning. The instantiated artifact augments text-based learning resources and facilitates learning in a contextsensitive manner through multimodal output. The proof-of-concept evaluation with 11 experienced teachers and researchers in the field of didactics confirms the usefulness of these design principles and suggests refinements of the artifact

Influence of Temperature, Hypercapnia, and Development on the Relative Expression of Different Hemocyanin Isoforms in the Common Cuttlefish Sepia officinalis

The cuttlefish Sepia officinalis expresses several hemocyanin isoforms with potentially different pH optima, indicating their reliance on efficient pH regulation in the blood. Ongoing ocean warming and acidification could influence the oxygen-binding properties of respiratory pigments in ectothermic marine invertebrates. This study examined whether S. officinalis differentially expresses individual hemocyanin isoforms to maintain optimal oxygen transport during development and acclimation to elevated seawater pCO2 and temperature. Using quantitative PCR, we measured relative mRNA expression levels of three different hemocyanin isoforms in several ontogenetic stages (embryos, hatchlings, juveniles, and adults), under different temperatures and elevated seawater pCO2. Our results indicate moderately altered hemocyanin expression in all embryonic stages acclimated to higher pCO2, while hemocyanin expression in hatchlings and juveniles remained unaffected. During the course of development, total hemocyanin expression increased independently of pCO2 or thermal acclimation status. Expression of isoform 3 is reported for the first time in a cephalopod in this study and was found to be generally low but highest in the embryonic stages (0.2% of total expression). Despite variable hemocyanin expression, hemolymph total protein concentrations remained constant in the experimental groups. Our data provide first evidence that ontogeny has a stronger influence on hemocyanin isoform expression than the environmental conditions chosen, and they suggest that hemocyanin protein abundance in response to thermal acclimation is regulated by post-transcriptional/translational rather than by transcriptional modifications