Preliminary steps toward artificial protocell computation

Protocells are hypothesised as a transitional phase in the origin of life, prior to the evolution of fully functional prokaryotic cells. The work reported here is being done in the context of the PACE project, which is investigating the fabrication of artificial protocells de novo. We consider here the important open question of whether or how articifial protocells (if or when they are successfully fabricated) might be applied as “computing” devices—what sort of computing might they be suitable for, and how might they be “programmed”? We also present some preliminary analysis of a crude model of such “evolutionary protocell computation”

Community-based post-editing of machine-translated content: monolingual vs. bilingual

We carried out a machine-translation postediting pilot study with users of an IT support forum community. For both language pairs (English to German, English to French), 4 native speakers for each language were recruited. They performed monolingual and bilingual postediting tasks on machine-translated forum content. The post-edited content was evaluated using human evaluation (fluency, comprehensibility, fidelity). We found that monolingual post-editing can lead to improved fluency and comprehensibility scores similar to those achieved through bilingual post-editing, while we found that fidelity improved considerably more for the bilingual set-up. Furthermore, the performance across post-editors varied greatly and it was found that some post-editors are able to produce better quality in a monolingual set-up than others

Psychometric evaluation of disordered eating measures in bariatric surgery candidates

Introduction: Assessment of disordered eating is common in bariatric surgery candidates, yet psychometric properties of disordered eating measures in this population are largely unknown. Methods: Measures were completed by 405 adult bariatric surgery candidates at pre-surgical consultation. Fit of the original scale structures was tested using confirmatory factor analysis (CFA) and alternative factor solutions were generated using exploratory factor analysis (EFA). Reliability (internal consistency), construct validity (convergent and divergent) and criterion validity (with the EDE as criterion) were assessed. Materials: The measures prioritised for evaluation are the following: Eating Disorder Examination Questionnaire (EDE-Q; n = 405), Three-Factor EatingQuestionnaire (TFEQ; n = 405), Questionnaire of Eating and Weight Patterns Revised (QEWP-R; n = 204), Clinical Impairment Assessment (CIA; n = 204) and the Eating Disorder Examination clinical interview (EDE; n = 131). Results: CFA revealed adequate fit for only the CIA in its current form (CFI = 0.925, RMSEA = 0.096). EFA produced revised scales with improved reliability for the EDE, EDE-Q and TFEQ. Reliability of revised subscales was improved (original scales α = 0.43–0.82; revised scales α = 0.67–0.93). Correlational analyses of the CIA and revised versions of remaining scales with measures of psychological wellbeing and impairment revealed adequate convergent validity. All measures differentiated an EDE-classified disordered eating group from a non-disordered eating group (criterion validity). Diagnostic concordance between the EDE, EDE-Q and QEWP-R was low, and identification of disordered eating behaviours was inconsistent across measures. Conclusions: Findings highlight the limitations of existing disordered eating questionnaires in bariatric surgery candidates. Results suggest revised assessments are required to overcome these limitations and ensure that measures informing clinical recommendations regarding patient care are reliable and valid

Genetics and genomics of myxomatous mitral valve disease in dogs

As a result of its unique evolutionary history, the modern dog (Canis lupus familiaris) has a simplified genetic landscape that makes it a strong model for investigating the genetic basis of breed specific traits and diseases. This thesis applies genomic methodologies to a complex disease, myxomatous mitral valve disease (MMVD), with the primary aim of improving our understanding of its genetic basis. MMVD is an acquired disease of the dog that causes valvular dysfunction and may result in the development of congestive heart failure (CHF). In dogs, MMVD is the most frequent cause of cardiovascular morbidity and mortality, and despite a thorough understanding of the clinical aspects, the genetic mechanisms that drive disease onset and progression are uncertain. Current MMVD research supports a polygenic mode of inheritance and exemplifies the difficulty in identifying disease risk variants in complex traits. In this thesis, genomic workflows are used to investigate MMVD in an Australian population of Cavalier King Charles Spaniels (CKCS), a breed disproportionately affected by the trait. I first assessed the strength of MMVD phenotypes for use in comparative genomic studies. Then, through bioinformatic approaches, I investigated the genetic landscape of the disease in this breed. Using genomic tools developed for the dog and a combined approach of objective phenotyping, I was able to thoroughly explore the genetics and genomics of MMVD in the CKCS using different types of genomic analyses. In doing so, I was able to demonstrate the utility of pedigreed breeds in the investigation of complex traits and the versatility of genomic datasets. Throughout this thesis MMVD associated loci, candidate genes and putative functional variants are reported

Complete Characterization of Quantum-Optical Processes

The technologies of quantum information and quantum control are rapidly improving, but full exploitation of their capabilities requires complete characterization and assessment of processes that occur within quantum devices. We present a method for characterizing, with arbitrarily high accuracy, any quantum optical process. Our protocol recovers complete knowledge of the process by studying, via homodyne tomography, its effect on a set of coherent states, i.e. classical fields produced by common laser sources. We demonstrate the capability of our protocol by evaluating and experimentally verifying the effect of a test process on squeezed vacuum.Comment: 5 pages, 4 figure

Silica-on-Silicon Waveguide Quantum Circuits

Quantum technologies based on photons are anticipated in the areas of information processing, communication, metrology, and lithography. While there have been impressive proof-of-principle demonstrations in all of these areas, future technologies will likely require an integrated optics architecture for improved performance, miniaturization and scalability. We demonstrated high- fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits, including two-photon quantum interference with a visibility of 94.8(5)%; a controlled-NOT gate with logical basis fidelity of 94.3(2)%; and a path entangled state of two photons with fidelity >92%.Comment: 4 pages, 4 figures, comments welcom

Cellular computation using classifier systems

The EU FP6 Integrated Project PACE ('Programmable Artificial Cell Evolution') is investigating the creation, de novo, of chemical 'protocells'. These will be minimal 'wetware' chemical systems integrating molecular information carriers, primitive energy conversion (metabolism) and containment (membrane). Ultimately they should be capable of autonomous reproduction, and be 'programmable' to realise specific desired function. A key objective of PACE is to explore the application of such protocell technology to build novel nanoscale computational devices. Our contribution to this project is to investigate approaches to adding minimal computational capability to protocells. We introduce the Molecular Classifier System (MCS) to represent the internal molecular reactions of the protocell. Reactions in the MCS are constrained as follows: The products of the reaction depend on the reactants and the environment in which the reaction took place; The reactions that can happen depend on the physical and chemical structure of the reacting compounds. In our MCS, there are reactants and reaction rules. The rules determine the reactants and the products for a given interaction. These simple computational processes may also help in understanding the origins of Cell Signaling Networks(CSNs). CSNs are complex bio-chemical networks responsible for coordinating and controlling cellular activities. CSNs can therefore be regarded as computational systems. To understand the evolution of such complex computational systems as found in nature, we will distinguish the minimal computational properties fundamental for the survival of a protocell

Kinematics of the ring-like nebula SuWt 2

We present the first detailed spatio-kinematical analysis and modelling of the Southern planetary nebula SuWt 2. This object presents a problem for current theories of planetary nebula formation and evolution, as it is not known to contain a central post-main sequence star. Deep narrowband [NII]6584 images reveal the presence of faint bipolar lobes emanating fromthe edges of the nebular ring. Longslit observations of the H-alpha and [NII]6584 emission lines were obtained using EMMI on the 3.6-m ESO-NTT. The spectra reveal the nebular morphology as a bright torus encircling the waist of an extended bipolar structure. By deprojection, the inclination of the ring is found to be 68\degr $\pm$ 2\degr (c.f. ~90\degr for the double A-type binary believed to lie at the centre of the nebula), and the ring expansion velocity is found to be 28 km/s. Our findings are discussed with relation to possible formation scenarios for SuWt 2. Through comparison of the nebular heliocentric systemic velocity, found here to be -25 $\pm$ 5 km/s, and the heliocentric systemic velocity of the double A-type binary, we conclude that neither component of the binary could have been the nebular progenitor. However, we are unable to rule out the presence of a third component to the system, which would have been the nebula progenitor.Comment: 7 pages, 4 figures. Accepted for publication in MNRA