Retinal gene therapy with a large MYO7A cDNA using adeno-associated virus.

Usher 1 patients are born profoundly deaf and then develop retinal degeneration. Thus they are readily identified before the onset of retinal degeneration, making gene therapy a viable strategy to prevent their blindness. Here, we have investigated the use of adeno-associated viruses (AAVs) for the delivery of the Usher 1B gene, MYO7A, to retinal cells in cell culture and in Myo7a-null mice. MYO7A cDNA, under control of a smCBA promoter, was packaged in single AAV2 and AAV5 vectors and as two overlapping halves in dual AAV2 vectors. The 7.9-kb smCBA-MYO7A exceeds the capacity of an AAV vector; packaging of such oversized constructs into single AAV vectors may involve fragmentation of the gene. Nevertheless, the AAV2 and AAV5 single vector preparations successfully transduced photoreceptor and retinal pigment epithelium cells, resulting in functional, full-length MYO7A protein and correction of mutant phenotypes, suggesting successful homologous recombination of gene fragments. With discrete, conventional-sized dual AAV2 vectors, full-length MYO7A was detected, but the level of protein expression was variable, and only a minority of cells showed phenotype correction. Our results show that MYO7A therapy with AAV2 or AAV5 single vectors is efficacious; however, the dual AAV2 approach proved to be less effective

Hamiltonian simulation of the Schwinger model at finite temperature

Using Matrix Product Operators (MPO) the Schwinger model is simulated in thermal equilibrium. The variational manifold of gauge invariant MPO is constructed to represent Gibbs states. As a first application the chiral condensate in thermal equilibrium is computed and agreement with earlier studies is found. Furthermore, as a new application the Schwinger model is probed with a fractional charged static quark-antiquark pair separated infinitely far from each other. A critical temperature beyond which the string tension is exponentially suppressed is found, which is in qualitative agreement with analytical studies in the strong coupling limit. Finally, the CT symmetry breaking is investigated and our results strongly suggest that the symmetry is restored at any nonzero temperature.Comment: Updated manuscript matching its published version: more detailed continuum extrapolation of chiral condensate in section II

Tensor networks for gauge field theories

Over the last decade tensor network states (TNS) have emerged as a powerful tool for the study of quantum many body systems. The matrix product states (MPS) are one particular class of TNS and are used for the simulation of (1+1)-dimensional systems. In this proceeding we use MPS to determine the elementary excitations of the Schwinger model in the presence of an electric background field. We obtain an estimate for the value of the background field where the one-particle excitation with the largest energy becomes unstable and decays into two other elementary particles with smaller energy.Comment: Proceeding of talk presented at the 33rd International Symposium on Lattice Field Theory, 14-18 July 2015, Kobe, Japan; Proceeding of talk presented at The European Physical Society Conference on High Energy Physics, 22-29 July 2015, Vienna, Austria (PoS(EPS-HEP2015)375

A method of rapid and automatic search for radio signals within the HF band

Imperial Users onl

Innovating out of the Fishmeal Trap: The role of Insect-Based Fish Feed in Consumers’ Preferences for Fish Attributes

The purpose of the study was to examine the potential market impacts of the use of insect-based protein for fish feed as an innovative approach out of the fish-meal trap. An online questionnaire was used to elicit information on fish consumption choices among 610 German consumers using a Discrete Choice Experiment. Mixed logit and latent class logit models were used to model consumers’ preference heterogeneity. Results showed, that consumers’ preferences for fish attributes such as filets, freshness, ecolabelling and domestic production are heterogeneous and important in consumption choices. The minor share of the respondents was sensitive, while the remaining was indifferent regarding the use of insect based protein as feed in trout production. For this sensitive segment, consumption would be expected to be reduced unless the price is reduced or other attributes such as convenience aspects are improved. The implication is that firms can substitute without a significant impact on the market demand given that the majority of consumers are indifferent regarding feed sources for trout production. As a result, it provides an innovative way to ensure sustainable use of resources and reduces the threat of fish meal trap while reducing pressure on the already over-exploited marine life. The results provide first insights into the market impact of using insects in the animal protein value chain. It is important especially with Europe’s recent lift of the ban on using insect-based protein in the animal food industry

Matrix product states for Hamiltonian lattice gauge theories

Over the last decade tensor network states (TNS) have emerged as a powerful tool for the study of quantum many body systems. The matrix product states (MPS) are one particular case of TNS and are used for the simulation of 1+1 dimensional systems. In [1] we considered the MPS formalism for the simulation of the Hamiltonian lattice gauge formulation of 1+1 dimensional one flavor quantum electrodynamics, also known as the massive Schwinger model. We deduced the ground state and lowest lying excitations. Furthermore, we performed a full quantum real-time simulation for a quench with a uniform background electric field. In this proceeding we continue our work on the Schwinger model. We demonstrate the advantage of working with gauge invariant MPS by comparing with MPS simulations on the full Hilbert space, that includes numerous non-physical gauge variant states. Furthermore, we compute the chiral condensate and recover the predicted UV-divergent behavior.Comment: presented at the 32nd International Symposium on Lattice Field Theory (Lattice 2014), 23 - 28 June 2014, New York, US

Real-time simulation of the Schwinger effect with Matrix Product States

Matrix Product States (MPS) are used for the simulation of the real-time dynamics induced by an electric quench on the vacuum state of the massive Schwinger model. For small quenches it is found that the obtained oscillatory behavior of local observables can be explained from the single-particle excitations of the quenched Hamiltonian. For large quenches damped oscillations are found and comparison of the late time behavior with the appropriate Gibbs states seems to give some evidence for the onset of thermalization. Finally, the MPS real-time simulations are explicitly compared with the semi-classical approach and, as expected, agreement is found in the limit of large quenches.Comment: Small changes, matching its published versio

Matrix product states for gauge field theories

The matrix product state formalism is used to simulate Hamiltonian lattice gauge theories. To this end, we define matrix product state manifolds which are manifestly gauge invariant. As an application, we study 1+1 dimensional one flavour quantum electrodynamics, also known as the massive Schwinger model, and are able to determine very accurately the ground state properties and elementary one-particle excitations in the continuum limit. In particular, a novel particle excitation in the form of a heavy vector boson is uncovered, compatible with the strong coupling expansion in the continuum. We also study non-equilibrium dynamics by simulating the real-time evolution of the system induced by a quench in the form of a uniform background electric field.Comment: expanded discussion on real-time evolution, matching the published versio