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Molecule-by-molecule construction has for years offered the tantalising prospect of atomic-scale devices. Current transistor fabrication techniques have for decades moved toward progressively smaller dimensions. This has driven interest in ‘bottom up’ routes to nanofabrication, where atoms and molecules are arranged into a desired structure. The scanning tunnelling microscope (STM) offers such a route. Nanofabrication wth STM lithography can reach sub-nanometre resolution. To achieve such control over individual molecules, a sound understanding of the behaviour of molecules on the surface is fundamentally important. In particular, the behaviour of aromatic organic molecules on surfaces is important for many technologies. Part II of this thesis presents a study of thermally activated movement of aromatic molecules on Si(111)-7 × 7, as recorded by STM. There are distinct variations in the measured rates of thermal displacement and desorption, determined by the different binding sites within the Si(111)-7 × 7 unit cell. The variation in the rates is a consequence of differences in both the energy barriers and Arrhenius prefactors. We reveal site-preference in the adsorption site of an aromatic molecule as it enters the surface from the gas phase via a physisorbed precursor. The complexity of the adsorption mechanism cannot be properly captured by the Langmuir isotherm. A Monte-Carlo simulation that takes into account a mobile physisorbed precursor accurately describes the adsorption process, highlighting the importance of molecular kinetics during adsorption. Part III of this thesis presents STM induced manipulation of aromatic molecules on Si(111)-7 × 7. A high voltage pulse at a point of the Si(111)-7 × 7 surface can desorb benzene, toluene, or chlorobenzene upwards of ten nanometres away from the tunnel junction. Increasing the current or time of the pulse, and hence the number of electrons, causes more molecules to be desorbed. This creates a depopulated region around the pulse site. For benzene, toluene, or chlorobenzene, the threshold bias to the effect is 2.0 V, below which no desorption occurs. Electrons travel across the surface isotropically before inducing desorption in a single electron process (1.18 ± 0.24 e−). Analysis of the effect at different temperatures and pulse voltages reveals that the injected electrons undergo diffusive motion between tip & molecule. The radius of the depopulated region decreases with decreasing temperature, but is constant for pulse voltages between 2.0 − 2.8 V. Drawing comparisons between 2 photon photoemission studies of the Si(111)-7 × 7 surface reveals a common electronic state at 2.0 V through which the electrons propagate the surface. The final chapter describes precise current injections made directly into toluene molecules adsorbed on Si(111)-7 × 7. Injecting directly into the molecule reveals the threshold to desorption of 1.4 eV. The difference in thresholds between locally and nonlocally induced desorption makes it clear that the 2.0 V threshold is a property of the surface, not the molecule.

Commercially impactful quantum algorithms such as quantum chemistry and Shor's algorithm require a number of qubits and gates far beyond the capacity of any existing quantum processor. Distributed architectures, which scale horizontally by networking modules, provide a route to commercial utility and will eventually surpass the capability of any single quantum computing module. Such processors consume remote entanglement distributed between modules to realize distributed quantum logic. Networked quantum computers will therefore require the capability to rapidly distribute high fidelity entanglement between modules. Here we present preliminary demonstrations of some key distributed quantum computing protocols on silicon T centres in isotopically-enriched silicon. We demonstrate the distribution of entanglement between modules and consume it to apply a teleported gate sequence, establishing a proof-of-concept for T centres as a distributed quantum computing and networking platform.

There are some long-established biases in atmospheric models that originate from the representation of tropical convection. Previously, it has been difficult to separate cause and effect because errors are often the result of a number of interacting biases. Recently, researchers have gained the ability to run multiyear global climate model simulations with grid spacings small enough to switch the convective parameterization off, which permits the convection to develop explicitly. There are clear improvements to the initiation of convective storms and the diurnal cycle of rainfall in the convection-permitting simulations, which enables a new process-study approach to model bias identification. In this study, multiyear global atmosphere-only climate simulations with and without convective parameterization are undertaken with the Met Office Unified Model and are analyzed over the Maritime Continent region, where convergence from sea-breeze circulations is key for convection initiation. The analysis shows that, although the simulation with parameterized convection is able to reproduce the key rain-forming sea-breeze circulation, the parameterization is not able to respond realistically to the circulation. A feedback of errors also occurs: the convective parameterization causes rain to fall in the early morning, which cools and wets the boundary layer, reducing the land–sea temperature contrast and weakening the sea breeze. This is, however, an effect of the convective bias, rather than a cause of it. Improvements to how and when convection schemes trigger convection will improve both the timing and location of tropical rainfall and representation of sea-breeze circulations.

Present treatment strategies for rheumatoid arthritis include use of disease-modifying antirheumatic drugs, but a minority of patients achieve a good response. We aimed to test the hypothesis that an improved outcome can be achieved by employing a strategy of intensive outpatient management of patients with rheumatoid arthritis—for sustained, tight control of disease activity—compared with routine outpatient care. We designed a single-blind, randomised controlled trial in two teaching hospitals. We screened 183 patients for inclusion. 111 were randomly allocated either intensive management or routine care. Primary outcome measures were mean fall in disease activity score and proportion of patients with a good response (defined as a disease activity score <2·4 and a fall in this score from baseline by >1·2). Analysis was by intention-to-treat. One patient withdrew after randomisation and seven dropped out during the study. Mean fall in disease activity score was greater in the intensive group than in the routine group (–3·5 vs –1·9, difference 1·6 [95% CI 1·1–2·1], p<0·0001). Compared with routine care, patients treated intensively were more likely to have a good response (definition, 45/55 [82%] vs 24/55 [44%], odds ratio 5·8 [95% CI 2·4–13·9], p<0·0001) or be in remission (disease activity score <1·6; 36/55 [65%] vs 9/55 [16%], 9·7 [3·9–23·9], p<0·0001). Three patients assigned routine care and one allocated intensive management died during the study; none was judged attributable to treatment. A strategy of intensive outpatient management of rheumatoid arthritis substantially improves disease activity, radiographic disease progression, physical function, and quality of life at no additional cost.

In atmospheric models with kilometer‐scale grids the resolution approaches the scale of convection. As a consequence the most energetic eddies in the atmosphere are partially resolved and partially unresolved. The modeling challenge to represent convection partially explicitly and partially as a subgrid process is called the convective gray zone problem. The gray zone issue has previously been discussed in the context of regional models, but the evolution in regional models is constrained by the lateral boundary conditions. Here we explore the convective gray zone starting from a defined global configuration of the Met Office Unified Model using initialized forecasts and comparing different model formulations to observations. The focus is on convection and turbulence, but some aspects of the model dynamics are also considered. The global model is run at nominal 5 km resolution and thus contributions from both resolved and subgrid turbulent and convective fluxes are non‐negligible. The main conclusion is that in the present assessment, the configurations which include scale‐aware turbulence and a carefully reduced and simplified mass‐flux convection scheme outperform both the configuration with fully parameterized convection as well as a configuration in which the subgrid convection parameterization is switched off completely. The results are more conclusive with regard to convective organization and tropical variability than extratropical predictability. The present study thus endorses the strategy to further develop scale‐aware physics schemes and to pursue an operational implementation of the global 5 km‐resolution model to be used alongside other ensemble forecasts to allow researchers and forecasters to further assess these simulations. Plain Language Summary An in‐depth exploration of kilometer‐scale global atmospheric modeling in the context of the current Met Office modeling system, the Met Office Unified Model, is presented. All simulations were performed using a global atmosphere model at nominal 5 km resolution. The model resolution thus resides in the so‐called convective gray zone where the grid length approaches the scale of turbulence and convection, and contributions from both resolved and subgrid convective and turbulent fluxes are non‐negligible. A case study approach has been taken in which various testbed cases are defined and model forecasts are evaluated against observations. The focus is on the representation of convection, turbulence and dynamics, the key aspects of the model formulation in the convective gray zone. The main finding is that in the present assessment the configurations which include a scale‐aware representation of turbulence and a carefully reduced and simplified convection scheme outperform both the reference model with fully parameterized convection as well as a configuration in which the subgrid convection parameterization is switched off completely. An outlook on further work toward the development of an adequate kilometer‐scale resolution global coupled modeling system for use across weather and climate time scales is given. Key Points The representation of turbulence and convection in the convective gray zone is investigated at global 5 km resolution In the examined context a reduced mass‐flux convection scheme is beneficial in 5 km‐resolution global model forecasts The assessment is more conclusive with regard to convective organization and tropical variability than extratropical predictability

1. Declines in area and quality of species-rich mesotrophic and calcareous grasslands have occurred all across Europe. While the European Union has promoted schemes to restore these grasslands, the emphasis for management has remained largely focused on plants. Here we focus on restoration of the phytophagous beetles of these grasslands. Although local management, particularly that which promotes the establishment of host plants, is key to restoration success, dispersal limitation is also likely to be an important limiting factor during the restoration of phytophagous beetle assemblages. 2. Using a 3-year multi-site experiment, we investigated how restoration success of phytophagous beetles was affected by hay-spreading management (intended to introduce target plant species), success in restoration of the plant communities and the landscape context within which restoration was attempted. 3. Restoration success of the plants was greatest where green hay spreading had been used to introduce seeds into restoration sites. Beetle restoration success increased over time, although hayspreading had no direct effect. However, restoration success of the beetles was positively correlated with restoration success of the plants. 4. Overall restoration success of the phytophagous beetles was positively correlated with the proportion of species-rich grassland in the landscape, as was the restoration success of the polyphagous beetles. Restoration success for beetles capable of flight and those showing oligophagous host plant specialism were also positively correlated with connectivity to species-rich grasslands. There was no indication that beetles not capable of flight showed greater dependence on landscape scale factors than flying species. 5. Synthesis and applications. Increasing the similarity of the plant community at restoration sites to target species-rich grasslands will promote restoration success for the phytophagous beetles.However, landscape context is also important, with restoration being approximately twice as successful in those landscapes containing high as opposed to low proportions of species-rich grassland.By targeting grassland restoration within landscapes containing high proportions of species-rich grassland, dispersal limitation problems associated with restoration for invertebrate assemblages are more likely to be overcome.

Abstract The specific activity of the $$\\beta $$ β decay of $$^{39}$$ 39 Ar in atmospheric argon is measured using the DEAP-3600 detector. DEAP-3600, located 2 km underground at SNOLAB, uses a total of (3269 ± 24) kg of liquid argon distilled from the atmosphere to search for dark matter. This detector is well-suited to measure the decay of $$^{39}$$ 39 Ar owing to its very low background levels. This is achieved in two ways: it uses low background construction materials; and it uses pulse-shape discrimination to differentiate between nuclear recoils and electron recoils. With 167 live-days of data, the measured specific activity at the time of atmospheric extraction is (0.964 ± 0.001 $$_\\textrm{stat}$$ stat ± 0.024 $$_\\textrm{sys}$$ sys ) Bq/kg $$_\\textrm{atmAr}$$ atmAr , which is consistent with results from other experiments. A cross-check analysis using different event selection criteria and a different statistical method confirms the result.