The Lateglacial history of Bassenthwaite Lake and adjacent areas, Lake District, UK; a sub-bottom profiling and geomorphological investigation

The glacial history of Bassenthwaite Lake and adjacent areas is poorly understood despite the English Lake District being a key area for assessing the dynamics of the British-Irish ice sheet. This project undertook geomorphological mapping and sub-surface geophysical investigations in order to investigate the glacial history of Bassenthwaite Lake. Drumlins and moraine ridges adjacent to the lake point to a relatively simple ice advance and retreat during the Last Glacial Maximum (LGM), but sub-bottom profile data from the lake floor suggests a more complex glacial history with a lower basement till or bedrock overlain by glaciolacustrine and glaciofluvial sediments. An eroded lower till or bedrock illustrates erosion potentially taking place during LGM ice coverage with the Bassenthwaite basin entirely inundated at this period. Moraine ridges along the length of Bassenthwaite Lake illustrate punctuated retreat of a constrained Lateglacial valley glacier. In addition to this, ice-marginal fluctuations are recorded through localised deformation within glaciolacustrine sediments. Continued retreat of the glacier results in the deposition of an upper glaciolacustrine sequence with ice-berg rafted debris identified. The identification of a re-advance till unit and the deformation of a lower glaciolacustrine sequence illustrates a fluctuating ice margin, which in some places re-advanced up to ~ 1 km and points to a dynamic ice mass occupying the Bassenthwaite basin. A drumlin was also investigated through sub-bottom profiling and was interpreted to have been created through erosion of the underlying bedrock. Following this, sedimentary packages overlie and infill the drumlin with two glacier re-advance events resulting in drumlinisation. It is clear that sub-bottom profiling has the potential to illustrate the internal composition and structure of submerged drumlins in addition to providing valuable information into Lateglacial glacier retreat dynamics

Constraints on sigma(8) from galaxy clustering in N-body simulations and semi-analytic models

We generate mock galaxy catalogues for a grid of different cosmologies, using rescaled N-body simulations in tandem with a semi-analytic model run using consistent parameters. Because we predict the galaxy bias, rather than fitting it as a nuisance parameter, we obtain an almost pure constraint on sigma(8) by comparing the projected two-point correlation function we obtain to that from the Sloan Digital Sky Survey (SDSS). A systematic error arises because different semi-analytic modelling assumptions allow us to fit the r-band luminosity function equally well. Combining our estimate of the error from this source with the statistical error, we find sigma(8) = 0.97 +/- 0.06. We obtain consistent results if we use galaxy samples with a different magnitude threshold, or if we select galaxies by b(J)-band rather than r-band luminosity and compare to data from the 2dF Galaxy Redshift Survey (2dFGRS). Our estimate for sigma(8) is higher than that obtained for other analyses of galaxy data alone, and we attempt to find the source of this difference. We note that in any case, galaxy clustering data provide a very stringent constraint on galaxy formation models.</p

Genome wide analysis of the complete GlnR nitrogen-response regulon in Mycobacterium smegmatis

BACKGROUND: Nitrogen is an essential element for bacterial growth and an important component of biological macromolecules. Consequently, responding to nitrogen limitation is critical for bacterial survival and involves the interplay of signalling pathways and transcriptional regulation of nitrogen assimilation and scavenging genes. In the soil dwelling saprophyte Mycobacterium smegmatis the OmpR-type response regulator GlnR is thought to mediate the transcriptomic response to nitrogen limitation. However, to date only ten genes have been shown to be in the GlnR regulon, a vastly reduced number compared to other organisms. RESULTS: We investigated the role of GlnR in the nitrogen limitation response and determined the entire GlnR regulon, by combining expression profiling of M. smegmatis wild type and glnR deletion mutant, with GlnR-specific chromatin immunoprecipitation and high throughput sequencing. We identify 53 GlnR binding sites during nitrogen limitation that control the expression of over 100 genes, demonstrating that GlnR is the regulator controlling the assimilation and utilisation of nitrogen. We also determine a consensus GlnR binding motif and identify key residues within the motif that are required for specific GlnR binding. CONCLUSIONS: We have demonstrated that GlnR is the global nitrogen response regulator in M. smegmatis, directly regulating the expression of more than 100 genes. GlnR controls key nitrogen stress survival processes including primary nitrogen metabolism pathways, the ability to utilise nitrate and urea as alternative nitrogen sources, and the potential to use cellular components to provide a source of ammonium. These studies further our understanding of how mycobacteria survive nutrient limiting conditions

A new approach for luminescence dating glaciofluvial deposits - High precision optical dating of cobbles

In recent years luminescence dating has increasingly been applied to date glaciofluvial sediments, but uncertainties about the degree of bleaching of the luminescence signal at deposition make dating of such sediments challenging. Here we test a new approach for luminescence dating of glaciofluvial sediments, based on the analysis of rock cores drilled from granite cobbles, and compare the luminescence ages generated against independent age control. Luminescence measurements from rock slices in cobble-sized clasts can be used to reconstruct the extent of bleaching, thereby giving greater confidence in the ages produced. This study illustrates that another important advantage of using cobbles is that at depths of 2 mm or more below the cobble surface >90% of the total dose rate arises from the cobble itself, making the dose rate insensitive to the water content of the sediment matrix. Ordinarily, uncertainties in estimating water content during burial are one of the largest sources of uncertainty in luminescence dating methods, and hence reducing the reliance upon the dose rate could be particularly advantageous for glacial deposits, where water contents can potentially be large and highly variable. Measurements of cobbles from Orrisdale Head, Isle of Man, demonstrate that the luminescence signal was completely bleached to depths of up to 12 mm into the cobble. Sampling of orientated cobbles from lithofacies diagnostic of bar-top environments was used to maximise the chances of exposure to sunlight. The upper-faces of these orientated cobble surfaces appear to be bleached to a greater depth than the lowermost faces. Data from 45 rock slices from these cobbles were tightly clustered, yielding a mean age of 20.7 ± 0.3 ka that is in agreement with independent age control. One of the well-bleached cobbles shows evidence of two discrete exposure events, potentially recording both the advance at 26.2 ± 0.8 ka, and retreat at 20.7 ± 0.3 ka, of the Irish Sea Ice Stream

Behaviors and adaptation of households living in an off-grid house

In the United Kingdom, the low carbon policy aspirations aim for new domestic buildings to be nearly zero carbon by 2020. In the past, the prevalent approach to low carbon performance has relied on the application of energy-efficient systems and low zero carbon technologies to offset the carbon emissions of buildings. However, research on performance gaps suggests that despite the good intentions of designers, the expected energy performance is rarely achieved during operation. Significant discrepancies have been found between as-designed and in-use performance, some of which may be the result of users’ behaviours. Off grid buildings can give an insight into the potential onsite energy generation, storage and demand reduction. This article presents a study that analysed an off-grid house built in 2013 as a working farm house to Code for Sustainable Homes level 3 (level 5 energy). The off grid systems in this case study are analogous to an intermittent future energy supply. The study identified the energy-efficiency behaviours of the households and their adaptation in the off-grid house that has been occupied for over a year. The monitored data of in-use performance has informed the analysis of households’ routines and practices that affected the energy and water consumption in the dwelling. The study suggests that the reductions in carbon emissions from the occupants’ behaviour were limited in their impact as the parasitic loads of the systems dominate. The findings bring attention to a number of aspects that could affect the success of carbon reduction measures in dwellings

Halo Mass Functions in Early Dark Energy Cosmologies

We examine the linear density contrast at collapse time, $\delta_c$ for large-scale structure in dynamical dark energy cosmologies, including models with early dark energy. Contrary to previous results, we find that as long as dark energy is homogeneous on small scales, $\delta_c$ is insensitive to dark energy properties for parameter values fitting current data, including the case of early dark energy. This is significant since using the correct $\delta_c$ is crucial for accurate Press-Schechter prediction of the halo mass function. Previous results have found an apparent failing of the extended Press-Schechter approach (Sheth-Tormen) for early dark energy. Our calculations demonstrate that with the correct $\delta_c$ the accuracy of this approach is restored. We discuss the significance of this result for the halo mass function and examine what dark energy physics would be needed to cause significant change in $\delta_c$, and the observational signatures this would leave.Comment: 5 pages, 2 figures. Accepted for MNRAS Letter

Squeezy Green Balls: Promoting Environmental Awareness through Playful Interactions

We need collective action to tackle global warming. However, research shows that people switch off from being concerned about the environment because they are often too busy, or fail to appreciate their ability to make a difference. An alternative approach is to run campaigns that are able to engage large numbers of people and engender feelings of concern and empowerment. This could then kick-start a range of pro-environmental habits. We present the development and evaluation of a playful installation that aimed to attract attention, and stimulate discussion about environmental issues amongst university staff and students. The first prototype was shown to successfully attract people to engage and interact with the installation. The second prototype was deployed in-the-wild, over the course of a week. We evaluated the extent to which the installation was successful at attracting attention, and in encouraging people to interact with it, to reflect on their habits and to discuss environmental issues with others. We found the Green Ball Kiosk was a fun way to raise discussions about green issues, to encourage the adoption of new environmentally friendly behaviours and to prompt people to maintain existing ones. We suggest that interactive installations such as this can be effective at promoting awareness and generating a ‘social buzz’ about environmental topics when exhibited as a temporary installation

Marine Copepods, The Wildebeest of the Ocean

Copepods are amongst the most abundant animals on our planet. Who knew?! These small (typically 1–10 mm) crustaceans are found in all of the world’s oceans and play an important role in regulating Earth’s climate. Like wildebeest in the Serengeti graze on grasslands and are food for lions, herbivorous copepods represent a vital link in oceanic food chains between microscopic algae and higher predators, such as fish, birds, and whales. A group of copepods called Calanus are particularly important in the Northern Hemisphere. These tiny-but-mighty animals also share the wildebeest’s need to make a large annual migration—but in their case, they sink thousands of meters downwards to spend the winter in the deep, dark ocean. Understanding the lives of marine copepods, and how their populations will respond to climate change, is crucial for predicting the future health of the marine environment and how it helps our planet