Lancaster University

About: Lancaster University is a education organization based out in Lancaster, Lancashire, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 13080 authors who have published 44563 publications receiving 1692277 citations. The organization is also known as: The University of Lancaster & Lancaster University.

Objects and Spaces

Abstract: Law's article begins by restating the classical ANT position that objects do not exist `in themselves' but are the effect of a performative stabilization of relational networks. In addition, these material enactments inevitably have a spatial dimension; they simultaneously establish spatial conditions for objectual identity, continuity, and difference. Space must not be reified as a natural, pre-existing container of the social and the material, but is itself a performance. Moreover, there are multiple forms of spatiality beyond the Euclidean space of regions (e.g. networks and fluids), and objects may exist and achieve homeomorphism within several different spatial systems. Technologies such as the Zimbabwe Bush Pump present a fluid object which is able to exist and cohere without the presence of fixed boundaries or the permanence of a particular functional definition. The network logic, however, which gravitates towards stability and functionality, tends to exclude and silence this spatial Other. An alternative political ontology is needed which goes beyond the reification of network space in order to give voice to the fluid objects which escape its unidimensional functionality.

Structure and function of the soil microbial community in microhabitats of a heavy metal polluted soil.

Abstract: Particle-size fractionation of a heavy metal polluted soil was performed to study the influence of environmental pollution on microbial community structure, microbial biomass, microbial residues and enzyme activities in microhabitats of a Calcaric Phaeocem In 1987, the soil was experimentally contaminated with four heavy metal loads: (1) uncontaminated controls; (2) light (300 ppm Zn, 100 ppm Cu, 50 ppm Ni, 50 ppm V and 3 ppm Cd); (3) medium; and (4) heavy pollution (two- and threefold the light load, respectively) After 10 years of exposure, the highest concentrations of microbial ninhydrin-reactive nitrogen were found in the clay (2–01 μm) and silt fractions (63–2 μm), and the lowest were found in the coarse sand fraction (2,000–250 μm) The phospholipid fatty acid analyses (PLFA) and denaturing gradient gel electrophoresis (DGGE) separation of 16S rRNA gene fragments revealed that the microbial biomass within the clay fraction was predominantly due to soil bacteria In contrast, a high percentage of fungal-derived PLFA 18 : 2ω6 was found in the coarse sand fraction Bacterial residues such as muramic acid accumulated in the finer fractions in relation to fungal residues The fractions also differed with respect to substrate utilization: Urease was located mainly in the phosphatase >urease >xylanase Heavy metal pollution did not markedly change the similarity pattern of the DGGE profiles and amino sugar concentrations Therefore, microbial biomass and enzyme activities seem to be more sensitive than 16S rRNA gene fragments and microbial amino-sugar-N to heavy metal treatment

A Taxonomy of Clutter Reduction for Information Visualisation

Abstract: Information visualisation is about gaining insight into data through a visual representation. This data is often multivariate and increasingly, the datasets are very large. To help us explore all this data, numerous visualisation applications, both commercial and research prototypes, have been designed using a variety of techniques and algorithms. Whether they are dedicated to geo-spatial data or skewed hierarchical data, most of the visualisations need to adopt strategies for dealing with overcrowded displays, brought about by too much data to fit in too small a display space. This paper analyses a large number of these clutter reduction methods, classifying them both in terms of how they deal with clutter reduction and more importantly, in terms of the benefits and losses. The aim of the resulting taxonomy is to act as a guide to match techniques to problems where different criteria may have different importance, and more importantly as a means to critique and hence develop existing and new techniques.

A Minorization-Maximization Method for Optimizing Sum Rate in the Downlink of Non-Orthogonal Multiple Access Systems

Abstract: Non-orthogonal multiple access (NOMA) systems have the potential to deliver higher system throughput, compared with contemporary orthogonal multiple access techniques. For a linearly precoded multiple-input single-output (MISO) system, we study the downlink sum rate maximization problem, when the NOMA principle is applied. Being a non-convex and intractable optimization problem, we resort to approximate it with a minorization-maximization algorithm (MMA), which is a widely used tool in statistics. In each step of the MMA, we solve a second-order cone program, such that the feasibility set in each step contains that of the previous one, and is always guaranteed to be a subset of the feasibility set of the original problem. It should be noted that the algorithm takes a few iterations to converge. Furthermore, we study the conditions under which the achievable rates maximization can be further simplified to a low complexity design problem, and we compute the probability of occurrence of this event. Numerical examples are conducted to show a comparison of the proposed approach against conventional multiple access systems.