Balancing the (carbon) budget: Using linear inverse models to estimate carbon flows and mass-balance 13C:15N labelling experiments in low oxygen sediments.

Over 1 million km² of seafloor experience permanent low-oxygen conditions within oxygen minimum zones (OMZs). OMZs are predicted to grow as a consequence of climate change, potentially affecting oceanic biogeochemical cycles. The Arabian Sea OMZ impinges upon the western Indian continental margin at bathyal depths (150 - 1500 m) producing a strong depth dependent oxygen gradient at the sea floor. The influence of the OMZ upon the short term processing of organic matter by sediment ecosystems was investigated using in situ stable isotope pulse chase experiments. These deployed doses of ¹³C:¹⁵N labeled organic matter onto the sediment surface at four stations from across the OMZ (water depth 540 - 1100 m; [O₂] = 0.35 - 15 μM). In order to prevent experimentally anoxia, the mesocosms were not sealed. ¹³C and ¹⁵N labels were traced into sediment, bacteria, fauna and ¹³C into sediment porewater DIC and DOC. However, the DIC and DOC flux to the water column could not be measured, limiting our capacity to obtain mass-balance for C in each experimental mesocosm. Linear Inverse Modeling (LIM) provides a method to obtain a mass-balanced model of carbon flow that integrates stable-isotope tracer data with community biomass and biogeochemical flux data from a range of sources. Here we present an adaptation of the LIM methodology used to investigate how ecosystem structure influenced carbon flow across the Indian margin OMZ. We demonstrate how oxygen conditions affect food-web complexity, affecting the linkages between the bacteria, foraminifera and metazoan fauna, and their contributions to benthic respiration. The food-web models demonstrate how changes in ecosystem complexity are associated with oxygen availability across the OMZ and allow us to obtain a complete carbon budget for the stationa where stable-isotope labelling experiments were conducted.

Unsettling modernity: Shifting values and changing housing styles in the Kathmandu Valley

Abstract

Culture has always been important for the character of the cities, as have the civic and public institutions that sustain a lifestyle and provide an identity. Substantial evidence of the unique historical, urban civilisation remains within the traditional settlements in the Kathmandu Valley in Nepal; manifested in houses, palaces, temples, rest houses, open spaces, festivals, rituals, customs and cultural institutions. Indigenous knowledge and practices prescribed the arrangement of houses, roads and urban spaces giving the city a distinctive physical form, character and a unique oriental nativeness. In technical sense, these societies did not have written rules for guiding development. In recent decades, the urban culture of the city has been changing with the forces of urbanisation and globalisation and the demand for new buildings and spaces. New residential design is increasingly dominated by distinctive patterns of Western suburban ideal comprising detached or semi-detached homes and high rise tower blocks. This architectural iconoclasm can be construed as a rather crude response to the indigenous culture and built form. The paper attempts to dismantle the current tension between traditional and contemporary ‘culture’ (and hence society) and housing (or built form) in the Kathmandu Valley by engaging in a discussion that cuts across space, time and meaning of architecture as we know it.

Social housing tenants, Climate Change and sustainable living: A study of awareness, behaviours and willingness to adapt

Despite a focus in the UK on providing sustainable housing in recent years, it is unlikely that targets set to reduce resource consumption in housing will be achieved without a greater focus on human behaviour. It is necessary to understand the actions of people occupying dwellings, as it is invariably the occupants rather than the buildings that decided whether or not to consume resources. In this paper the authors present a pilot study where 53 social housing tenant households in Northern Ireland were interviewed to ascertain their perceptions of Climate Change, their current behaviours and their willingness to reduce energy and water consumption in the home. The intention was to explore links between perceptions and reported behaviour as well as perceptions and willingness to reduce resource consumption. Results show that 77% of tenants believed Climate Change to be an important issue; 57% accepted that it is up to the individual to take responsibility for tackling Climate Change; and demonstrated a strong desire to make a difference to reduce their impact. The researchers identified both passive (devices) and active (behaviours) resource savings currently in place and established where further resource reduction was feasible based on tenants' willingness to alter their behaviours.

A Hybrid Swarm Based Approach in Addressing University Timetabling Problems

This paper is concerned with the application of an automated hybrid approach in addressing the university timetabling problem. The approach described is based on the nature-inspired artificial bee colony (ABC) algorithm. An ABC algorithm is a biologically-inspired optimization approach, which has been widely implemented in solving a range of optimization problems in recent years such as job shop scheduling and machine timetabling problems. Although the approach has proven to be robust across a range of problems, it is acknowledged within the literature that there currently exist a number of inefficiencies regarding the exploration and exploitation abilities. These inefficiencies can often lead to a slow convergence speed within the search process. Hence, this paper introduces a variant of the algorithm which utilizes a global best model inspired from particle swarm optimization to enhance the global exploration ability while hybridizing with the great deluge (GD) algorithm in order to improve the local exploitation ability. Using this approach, an effective balance between exploration and exploitation is attained. In addition, a traditional local search approach is incorporated within the GD algorithm with the aim of further enhancing the performance of the overall hybrid method. To evaluate the performance of the proposed approach, two diverse university timetabling datasets are investigated, i.e., Carter's examination timetabling and Socha course timetabling datasets. It should be noted that both problems have differing complexity and different solution landscapes. Experimental results demonstrate that the proposed method is capable of producing high quality solutions across both these benchmark problems, showing a good degree of generality in the approach. Moreover, the proposed method produces best results on some instances as compared with other approaches presented in the literature.

Housing, Regeneration and Community Asset Transfer

Community asset transfer enables local groups to own or manage a government owned facility and/or related services. For critics, it is merely an extension of roll-back neoliberalism, permitting the state to withdraw from welfare and transfer risk from local government to ill-defined communities. The paper uses quantitative and case study data from Northern Ireland to demonstrate its transformative potential by challenging the notion of private property rights, enabling communities to accumulate and endanger forms of cooperative consumption. It concludes by highlighting the implications for more progressive forms of social economics in relation to public and private markets and government sponsorship of its own development.