Discovery of relict subglacial lakes and their geometry and mechanism of drainage

Recent proxy measurements reveal that subglacial lakes beneath modern ice sheets periodically store and release large volumes of water, providing an important but poorly understood influence on contemporary ice dynamics and mass balance. This is because direct observations of how lake drainage initiates and proceeds are lacking. Here we present physical evidence of the mechanism and geometry of lake drainage from the discovery of relict subglacial lakes formed during the last glaciation in Canada. These palaeo-subglacial lakes comprised shallow (<10 m) lenses of water perched behind ridges orientated transverse to ice flow. We show that lakes periodically drained through channels incised into bed substrate (canals). Canals sometimes trend into eskers that represent the depositional imprint of the last high-magnitude lake outburst. The subglacial lakes and channels are preserved on top of glacial lineations, indicating long-term re-organization of the subglacial drainage system and coupling to ice flow.

Optimal day-ahead scheduling of integrated urban energy systems

An optimal day-ahead scheduling method (ODSM) for the integrated urban energy system (IUES) is introduced, which considers the reconfigurable capability of an electric distribution network. The hourly topology of a distribution network, a natural gas network, the energy centers including the combined heat and power (CHP) units, different energy conversion devices and demand responsive loads (DRLs), are optimized to minimize the day-ahead operation cost of the IUES. The hourly reconfigurable capability of the electric distribution network utilizing remotely controlled switches (RCSs) is explored and discussed. The operational constraints from the unbalanced three-phase electric distribution network, the natural gas network, and the energy centers are considered. The interactions between the electric distribution network and the natural gas network take place through conversion of energy among different energy vectors in the energy centers. An energy conversion analysis model for the energy center was developed based on the energy hub model. A hybrid optimization method based on genetic algorithm (GA) and a nonlinear interior point method (IPM) is utilized to solve the ODSM model. Numerical studies demonstrate that the proposed ODSM is able to provide the IUES with an effective and economical day-ahead scheduling scheme and reduce the operational cost of the IUES.

Garden Cities: A flawed model for Ecological Urbanism?

Since the beginning of the 20th century, the Garden City model has been a predominant theory emerging from Ecological Urbanism. In his book Howard observed the disastrous effects of rapid urbanization and as a response, proposed the Garden City. Although Howard’s proposal was first published in the late 1800’s, the clear imbalance that Howard aimed to address is still prevalent in the UK today. Each year, the UK wastes nearly 15 million tons of food, despite this an estimated 500,000 people in the UK go without sufficient access to food. While the urban population is rapidly increasing and cities are becoming hubs of economic activity, producing wealth and improving education and access to markets, it is within these cities that the imbalance is most evident, with a significant proportion of the world’s population with unmet needs living in urban areas. Despite Howard’s model being a response to 17th century London, many still consider the Garden City model to be an effective solution for the 21st century. In his book, Howard details the metrics required for the design of a Garden City. This paper will discuss how, by using this methodology and comparing it with more recent studies by Cornell University and Matthew Wheeland (Pure Energies); it is possible to test the validity of Howard’s proposal to establish whether the Garden City model is a viable solution to the increasing pressures of urbanization.
This paper outlines how the analysis of Howard’s proposal has shown the model to be flawed, incapable of producing enough food to sustain the proposed 32,000 population, with a capacity to produce only 23% of the food required to meet the current average UK consumption rate. Beyond the limited productive capacity of Howard’s model, the design itself does little to increase local resilience or the ecological base. This paper will also discuss how a greater understanding of the
Land-share requirements enables the design of a new urban model, building on the foundations initially laid out by Howard and combining a number of other theories to produce a more resilient and efficient model of ecological urbanism.

Bacteriophage Can Prevent Encrustation and Blockage of Urinary Catheters by Proteus mirabilis.

Proteus mirabilis forms dense crystalline biofilms on catheter surfaces that occlude urine flow, leading to serious clinical complications in long-term catheterized patients, but there are presently no truly effective approaches to control catheter blockage by this organism. This study evaluated the potential for bacteriophage therapy to control P. mirabilis infection and prevent catheter blockage. Representative in vitro models of the catheterized urinary tract, simulating a complete closed drainage system as used in clinical practice, were employed to evaluate the performance of phage therapy in preventing blockage. Models mimicking either an established infection or early colonization of the catheterized urinary tract were treated with a single dose of a 3-phage cocktail, and the impact on time taken for catheters to block, as well as levels of crystalline biofilm formation, was measured. In models of established infection, phage treatment significantly increased time taken for catheters to block (∼ 3-fold) compared to untreated controls. However, in models simulating early-stage infection, phage treatment eradicated P. mirabilis and prevented blockage entirely. Analysis of catheters from models of established infection 10 h after phage application demonstrated that phage significantly reduced crystalline biofilm formation but did not significantly reduce the level of planktonic cells in the residual bladder urine. Taken together, these results show that bacteriophage constitute a promising strategy for the prevention of catheter blockage but that methods to deliver phage in sufficient numbers and within a key therapeutic window (early infection) will also be important to the successful application of phage to this problem.