The role of acoustic templates, contextual information and visual representation in the combinatorial communication system of chestnut-crowned babblers

Many non-human animals produce vocalisations via the combination of multiple acoustic elements into larger sequences, a property referred to as combinatoriality. Chestnut crowned babblers (Pomatostomus ruficeps) are the only known species other than humans to use phonemic contrasts, i.e. the rearrangement of meaningless acoustic elements into meaningful calls, in the generation of vocal signals. Identifying the similarities and differences in phoneme use between humans and babblers, therefore, can potentially grant valuable insight into the evolution of this linguistic ability in humans. The primary goal of this thesis is to understand the cognitive mechanisms that underlie the reception of vocalisations generated via phonemic contrasts in chestnut crowned babblers. Specifically, I address the following research questions: 1) whether babblers are able to respond appropriately to vocal signals even when the constituent acoustic sub-units have been rearranged; 2) whether individuals are capable of integrating previously acquired contextual information in order to produce appropriate behavioural responses to ambiguous signals; and 3) whether babblers generate a visual mental image of signal referents upon reception of context-specific acoustic signals. I find that subjects respond appropriately to vocal stimuli even when the acoustic sub-units have been rearranged to differ from any existing call template, but only when the modified signal exhibits a high degree of acoustic similarity to the natural call. This suggests that babblers, as opposed to humans, possess flexible acoustic templates for their phoneme-based vocalisations. I also observe that subjects respond appropriately to ambiguous signals if they have been previously exposed to information which may disambiguate the meaning of future, uncertain stimuli. This extends the evidence for the integration of contextual information to an avian species exhibiting a combinatorial repertoire. Finally, I do not find evidence in support of the hypothesis that babblers generate visual mental images of signal referents upon reception of context-specific calls. Thus it remains as of yet unclear whether babblers respond to calls via a process of affect-conditioning, associative learning or conceptual semanticity. The findings of this thesis contribute to the field of comparative and combinatorial communication by describing some of the cognitive mechanisms which underlie the reception of phoneme-based vocalisations in an avian species

Nematic elastomers with aligned carbon nanotubes: new electromechanical actuators

We demonstrate, for the first time, the large electromechanical response in nematic liquid crystalline elastomers filled with a very low (~0.01%) concentration of carbon nanotubes, aligned along the nematic director at preparation. The nanotubes create a very large effective dielectric anisotropy of the composite. Their local field-induced torque is transmitted to the rubber-elastic network and is registered as the exerted uniaxial stress of order ~1kPa in response to a constant field of order ~1MV/m. We investigate the dependence of the effect on field strength, nanotube concentration and reproducibility under multiple field-on and -off cycles. The results indicate the potential of the nanotube-nematic elastomer composites as electrically driven actuators

Comparing different accelerometer cut-points for sedentary time in children

Actigraph accelerometers are hypothesized to be valid measurements for assessing children\u27s sedentary time. However, there is considerable variation in accelerometer cut-points used. Therefore, we compared the most common accelerometer sedentary cut-points of children performing sedentary behaviors. Actigraph Actitrainer uniaxial accelerometers were used to measure children\u27s activity intensity (29 children, 5-11 years old) during different activities, namely playing computer games, nonelectronic sedentary games, watching television and playing outdoors. A structured protocol was the criterion for assessing the validity of four common cut-points (100, 300, 800, 1100 counts/minute). The median counts during all sedentary behaviors were below the lowest comparison cut-point of 100 cpm. The 75th percentile values for the sedentary behaviors were always below the cut-point of 300 cpm. Our results suggest that the cut-point of <100 cpm is the most appropriate

Evidence for a quantum-spin-Hall phase in graphene decorated with Bi2Te3 nanoparticles

Realization of the quantum-spin-Hall effect in graphene devices has remained an outstanding challenge dating back to the inception of the field of topological insulators. Graphene's exceptionally weak spin-orbit coupling -stemming from carbon's low mass- poses the primary obstacle. We experimentally and theoretically study artificially enhanced spin-orbit coupling in graphene via random decoration with dilute Bi2Te3 nanoparticles. Remarkably, multi-terminal resistance measurements suggest the presence of helical edge states characteristic of a quantum-spin-Hall phase; the magnetic-field and temperature dependence of the resistance peaks, X-ray photoelectron spectra, scanning tunneling spectroscopy, and first-principles calculations further support this scenario. These observations highlight a pathway to spintronics and quantum-information applications in graphene-based quantum-spin-Hall platforms

A Pediatrics Utilization Study in The Netherlands to Identify Active Pharmaceutical Ingredients Suitable for Inkjet Printing on Orodispersible Films

Background: The use of medication in pediatrics, children aged 0-5 years, was explored so as to identify active pharmaceutical ingredients (APIs) suitable for inkjet printing on a plain orodispersible film (ODF) formulation in a pharmacy. Methods: The database IADB.nl, containing pharmacy dispensing data from community pharmacies in the Netherlands, was used to explore medication use in the age group of 0-5 years old, based on the Anatomical Therapeutic Chemical classification code (ATC code). Subsequently, a stepwise approach with four exclusion steps was used to identify the drug candidates for ODF formulation development. Results: there were 612 Active Pharmaceutical Ingredients (APIs) that were dispensed to the target group, mostly antibiotics. Of the APIs, 221 were not registered for pediatrics, but were used off-label. After the exclusion steps, 34 APIs were examined regarding their suitability for inkjet printing. Almost all of the APIs were sparingly water soluble to practically insoluble. Conclusion: Pharmaceutical inkjet printing is a suitable new technique for ODF manufacturing for pediatric application, however the maximal printed dose as found in the literature remained low. From the selected candidates, only montelukast shows a sufficiently high water-solubility to prepare a water-based solution. To achieve higher drug loads per ODF is ambitious, but is theoretically possible by printing multiple layers, using highly water-soluble APIs or highly loaded suspensions

Influence of Prior Imaging Information on Diagnostic Accuracy for Focal Skeletal Processes-A Retrospective Analysis of the Consistency between Biopsy-Verified Imaging Diagnoses

Introduction: Comparing imaging examinations with those previously obtained is considered mandatory in imaging guidelines. To our knowledge, no studies are available on neither the influence, nor the sequence, of prior imaging and reports on diagnostic accuracy using biopsy as the reference standard. Such data are important to minimize diagnostic errors and to improve the preparation of diagnostic imaging guidelines. The aim of our study was to provide such data. Materials and methods: A retrospective cohort of 216 consecutive skeletal biopsies from patients with at least 2 different imaging modalities (X-ray, CT and MRI) performed within 6 months of biopsy was identified. The diagnostic accuracy of the individual imaging modality was assessed. Finally, the possible influence of the sequence of imaging modalities was investigated. Results: No significant difference in the accuracy of the imaging modalities was shown, being preceded by another imaging modality or not. However, the sequence analyses indicate sequential biases, particularly if MRI was the first imaging modality. Conclusion: The sequence of the imaging modalities seems to influence the diagnostic accuracy against a pathology reference standard. Further studies are needed to establish evidence-based guidelines for the strategy of using previous imaging and reports to improve diagnostic accuracy