Simulating and visualising the hydrological and landscape impacts of reservoir engineering at Crummock Water, England

Eng. D. ThesisThe Earth’s 57,000 large water reservoirs have significant impacts on hydrology and landscapes. Meanwhile, environmental degradation is destabilising the climate, ecosystems, and hydrological functionality. In Europe and North America, landscape-scale environmental management schemes are being proposed, including reservoir decommissioning to rehabilitate river catchments. Yet, some proposed schemes have failed due to poor stakeholder engagement and shifting environmental baselines. This research has developed novel approachesto address these issues. It has applied these to Crummock Water raised lake in England, where United Utilities and the Environment Agency are investigating the feasibility of removing infrastructure to renaturalise the lake and the River Cocker. The hydrological impacts of anthropogenic modifications in Crummock Water’s catchment were assessed using existing data, expanded hydrometric monitoring, hydrological modelling, and archival research. Circa 1880, Crummock Water’s outlet was excavated and two timber weirs installed to control outflows. In 1903, the extant masonry weir was built, raising the lake level ~0.6 m. Abstraction reduces lake levels, which necessitates sluice operations to maintain outflows during dry periods, causing further drawdown. Hydrological models of reservoircontaining catchments should include reservoir processes. SHETRAN 4.5 (‘Reservoir’)software was developed to integrate reservoir structures and operations into a physically-based, spatially-distributed hydrology model. A SHETRAN-Reservoir model of the Crummock Water catchment substantially outperformed a SHETRAN-Standard model, particularly during and after dry periods. Several reservoir decommissioning scenarios were constructed. Simulations indicate that decommissioning would ameliorate drawdown of Crummock Water and make the River Cocker’s flow regime more dynamic. The simulated landscape impacts of reservoir engineering at Crummock Water were shown in the context of long-term catchment evolution using 4D landscape visualisation. The catchment’s evolution was conceptualised, before being digitally reconstructed and rendered using GeoVisionary software. The resulting 4D landscape model spanned 14,000 years, from the last Ice Age to (simulated) renaturalisation scenarios in 2030. The effects of 4D landscape visualisation on stakeholder attitudes were investigated, using surveys and workshops with 45 participants in two treatments (‘long’ and ‘short’ visualisation). It was hypothesised that ii presenting extended landscape evolution information would change (H1) stakeholder beliefs around catchment naturalness, and (H2) attitudes towards reservoir renaturalisation. Results showed that the workshops changed both beliefs and attitudes towards renaturalisation. Furthermore, the extended evolution information had a statistically significant effect on attitudes (H2), but not on beliefs (H1). This EngD has developed tools to support decision-making in reservoir engineering and landscape-scale environmental projects: firstly, hydrological and landscape models to show the impacts of reservoir decommissioning at Crummock Water; secondly, a generic freelyavailable physically-based, spatially-distributed modelling package for simulating the hydrological impacts of reservoir operations; thirdly, a new approach to visualising simulated hydrological changes, such as lake levels, and landscape evolution in 4D, and; fourthly, an approach to visualising proposed environmental management schemes in the context of longterm landscape evolution, to reset shifting environmental baselines. Finally, the research findings have been synthesised into a landscape visualisation development framework to support enhanced stakeholder engagement in future landscape-scale projects.Engineering and Physical Science Research Council (EPSRC) and United Utilities pl

Tackling the big questions: What research matters to Australian paediatricians?

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136534/1/jpc13453.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136534/2/jpc13453_am.pd

Polarization engineering in photonic crystal waveguides for spin-photon entanglers

By performing a full analysis of the projected local density of states (LDOS) in a photonic crystal waveguide, we show that phase plays a crucial role in the symmetry of the light-matter interaction. By considering a quantum dot (QD) spin coupled to a photonic crystal waveguide (PCW) mode, we demonstrate that the light-matter interaction can be asymmetric, leading to unidirectional emission and a deterministic entangled photon source. Further we show that understanding the phase associated with both the LDOS and the QD spin is essential for a range of devices that that can be realised with a QD in a PCW. We also show how quantum entanglement can completely reverse photon propagation direction, and highlight a fundamental breakdown of the semiclassical dipole approximation for describing light-matter interactions in these spin dependent systems.Comment: Updated version fixes some errors. The main changes have come in the second half of the paper, with a more in depth treatment of the scattering from dipoles inside the PC

An innovative hydrological model for the sparsely-gauged Essequibo River basin, northern Amazonia

Tropical river basins – crucial components of global water and carbon cycles – are threatened by logging, mining, agricultural conversion, and climate change. Thus, decision-makers require hydrological impact assessments to sustainably manage threatened basins, such as the ∼68,000 km2 Essequibo River basin in Guyana. Emerging global data products offer the potential to better understand sparsely-gauged basins. We combined new global meteorological and soils data with established in situ observations to build the first physically-based spatially-distributed hydrological model of the Essequibo. We developed new, open source, methods to translate global data (ERA5-Land, WFDE5, MSWEP, and IMERG) into a grid-based SHETRAN model. Comparing the performance of several global and local precipitation and evaporation datasets showed that WFDE5 precipitation, combined with ERA5-Land evaporation, yielded the best daily discharge simulations from 2000 to 2009, with close water balances (PBIAS = −3%) and good discharge peaks (NSE = 0.65). Finally, we tested model sensitivity to key parameters to show the importance of actual to potential evapotranspiration ratios, Strickler runoff coefficients, and subsurface saturated hydraulic conductivities. Our data translation methods can now be used to drive hydrological models nearly anywhere in the world, fostering the sustainable management of the Earth’s sparsely-gauged river basins

A reference human induced pluripotent stem cell line for large-scale collaborative studies.

Human induced pluripotent stem cell (iPSC) lines are a powerful tool for studying development and disease, but the considerable phenotypic variation between lines makes it challenging to replicate key findings and integrate data across research groups. To address this issue, we sub-cloned candidate human iPSC lines and deeply characterized their genetic properties using whole genome sequencing, their genomic stability upon CRISPR-Cas9-based gene editing, and their phenotypic properties including differentiation to commonly used cell types. These studies identified KOLF2.1J as an all-around well-performing iPSC line. We then shared KOLF2.1J with groups around the world who tested its performance in head-to-head comparisons with their own preferred iPSC lines across a diverse range of differentiation protocols and functional assays. On the strength of these findings, we have made KOLF2.1J and its gene-edited derivative clones readily accessible to promote the standardization required for large-scale collaborative science in the stem cell field

First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength of λ = 1.3 mm. The EHT data resolve a compact emission region with intrahour variability. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of 51.8 \ub1 2.3 μas (68% credible interval). The ring has modest azimuthal brightness asymmetry and a comparatively dim interior. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A* are consistent with the expected appearance of a Kerr black hole with mass ∼4 7 106 M☉, which is inferred to exist at this location based on previous infrared observations of individual stellar orbits, as well as maser proper-motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50\ub0), as well as nonspinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way, and for the first time we connect the predictions from dynamical measurements of stellar orbits on scales of 103-105 gravitational radii to event-horizon-scale images and variability. Furthermore, a comparison with the EHT results for the supermassive black hole M87* shows consistency with the predictions of general relativity spanning over three orders of magnitude in central mass

A Universal Power-law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows

We present a framework for characterizing the spatiotemporal power spectrum of the variability expected from the horizon-scale emission structure around supermassive black holes, and we apply this framework to a library of general relativistic magnetohydrodynamic (GRMHD) simulations and associated general relativistic ray-traced images relevant for Event Horizon Telescope (EHT) observations of Sgr A*. We find that the variability power spectrum is generically a red-noise process in both the temporal and spatial dimensions, with the peak in power occurring on the longest timescales and largest spatial scales. When both the time-averaged source structure and the spatially integrated light-curve variability are removed, the residual power spectrum exhibits a universal broken power-law behavior. On small spatial frequencies, the residual power spectrum rises as the square of the spatial frequency and is proportional to the variance in the centroid of emission. Beyond some peak in variability power, the residual power spectrum falls as that of the time-averaged source structure, which is similar across simulations; this behavior can be naturally explained if the variability arises from a multiplicative random field that has a steeper high-frequency power-law index than that of the time-averaged source structure. We briefly explore the ability of power spectral variability studies to constrain physical parameters relevant for the GRMHD simulations, which can be scaled to provide predictions for black holes in a range of systems in the optically thin regime. We present specific expectations for the behavior of the M87* and Sgr A* accretion flows as observed by the EHT

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis