Delay-rate tradeoff in ergodic interference alignment

Ergodic interference alignment, as introduced by Nazer et al (NGJV), is a technique that allows high-rate communication in n-user interference networks with fast fading. It works by splitting communication across a pair of fading matrices. However, it comes with the overhead of a long time delay until matchable matrices occur: the delay is q^n^2 for field size q. In this paper, we outline two new families of schemes, called JAP and JAP-B, that reduce the expected delay, sometimes at the cost of a reduction in rate from the NGJV scheme. In particular, we give examples of good schemes for networks with few users, and show that in large n-user networks, the delay scales like q^T, where T is quadratic in n for a constant per-user rate and T is constant for a constant sum-rate. We also show that half the single-user rate can be achieved while reducing NGJV's delay from q^n^2 to q^(n-1)(n-2). This extended version includes complete proofs and more details of good schemes for small n.Comment: Extended version of a paper presented at the 2012 International Symposium on Information Theory. 7 pages, 1 figur

Asymptotic Sum-Capacity of Random Gaussian Interference Networks Using Interference Alignment

We consider a dense n-user Gaussian interference network formed by paired transmitters and receivers placed independently at random in Euclidean space. Under natural conditions on the node position distributions and signal attenuation, we prove convergence in probability of the average per-user capacity C_Sigma/n to 1/2 E log(1 + 2SNR). The achievability result follows directly from results based on an interference alignment scheme presented in recent work of Nazer et al. Our main contribution comes through the converse result, motivated by ideas of `bottleneck links' developed in recent work of Jafar. An information theoretic argument gives a capacity bound on such bottleneck links, and probabilistic counting arguments show there are sufficiently many such links to tightly bound the sum-capacity of the whole network.Comment: 5 pages; to appear at ISIT 201

Development of methods for the in-vitro assessment of the adipogenesis and immunogenicity of human multipotent mesenchymal stromal cells

Adult mesenchymal stromal cells (MSCs) have enormous potential in tissue engineering and regenerative medicine applications. MSC have also been reported to be immune-privileged. The aim of this study was to develop methods to test two related hypotheses. Firstly, that MSCs will not directly stimulate allogeneic lymphocytes in classical lymphocyte proliferation assays carried out over 5-7 days due to lack of expression of immune-regulatory molecules (CD40, CD80, CD86 and MHC Class-II) but may be capable of the stimulation of allogeneic lymphocytes when cultured over extended time periods that allow the indirect pathway of antigen presentation. Secondly, that following differentiation of MSCs into mature differentiated adipose cells, the cells would become immunogenic or increase their immunogenicity, as determined by the stimulation of allogeneic peripheral blood mononuclear cells in lymphocyte transformation assays. MSCs from 4 human bone marrow donors were isolated, expanded and characterised and shown to conform to the ISCT definition of MSC through FACs analysis of key antigen expression and trilineage differentiation. MSCs (from donors 1-3) were differentiated into adipocytes, and current methodology for assaying adipogenesis was evaluated. A new fluorescent microplate assay was developed using DAPI to normalise for cell number and Nile red to stain for intracellular lipids, to generate a ratio of adipogenesis. Peripheral blood mononuclear cells (PBMCs) from 6 volunteers were isolated, in-vitro assay conditions for performing lymphocyte transformation assays (LTAs) were optimised, and the duration of the assays extended to 16-21 days. It was shown that undifferentiated MSCs stimulated PBMCs in all except 2 out of 24 cases, with the highest stimulation typically post-day 7 with stimulation indices as high as 36 observed. It was shown that MSCs differentiated into adipocytes also stimulated PBMCs with higher stimulation indices observed in differentiated MSCs compared to the undifferentiated counterparts. It was concluded that MSC, whether undifferentiated or differentiated into adipose cells, are indeed capable of stimulating a proliferative response in allogeneic lymphocytes. Therefore, the use of allogeneic MSCs in the traditional engineering setting may be limited, and a cautious approach should be taken before allogeneic MSCs are used in the regeneration or creation of tissue replacements for clinical use

Television wildlife programming as a source of popular scientific information: a case study of evolution

The wildlife television documentary is an important but problematic genre, located between education and entertainment. Noting that the genre has characteristics that may increase its impact on the audience, this paper reviews its potential significance for science communication through a case study of the presentation of issues relating to evolution. First, the continuing popular and political support for creationism is examined, and then the new movement in support of Intelligent Design Creationism outlined. Based on an extensive sample of internationally produced programs, the research findings discussed in the paper focus on two dominant sub-genres: “blue chip” and “presenter-led.” While the former has higher production values and asserts greater authority, the pressures for a strong narrative discourage explorations of the contingency and amorality of evolution. The outcome is, typically, a text that does not challenge creationist accounts and may even implicitly endorse them. Paradoxically, we argue, although the presenter-led format is regarded as lower status within the media industry, it may offer more opportunities for conveying the complexity that is associated with evolutionary accounts. The authors conclude that the market context of television wildlife programming means that educational and entertainment aims and claims are indeed in tension, but with a counter-intuitive outcome

Dedicated outreach service for hard to reach patients with tuberculosis in London: observational study and economic evaluation.

OBJECTIVE: To assess the cost effectiveness of the Find and Treat service for diagnosing and managing hard to reach individuals with active tuberculosis. DESIGN: Economic evaluation using a discrete, multiple age cohort, compartmental model of treated and untreated cases of active tuberculosis. SETTING: London, United Kingdom. Population Hard to reach individuals with active pulmonary tuberculosis screened or managed by the Find and Treat service (48 mobile screening unit cases, 188 cases referred for case management support, and 180 cases referred for loss to follow-up), and 252 passively presenting controls from London's enhanced tuberculosis surveillance system. MAIN OUTCOME MEASURES: Incremental costs, quality adjusted life years (QALYs), and cost effectiveness ratios for the Find and Treat service. RESULTS: The model estimated that, on average, the Find and Treat service identifies 16 and manages 123 active cases of tuberculosis each year in hard to reach groups in London. The service has a net cost of £1.4 million/year and, under conservative assumptions, gains 220 QALYs. The incremental cost effectiveness ratio was £6400-£10,000/QALY gained (about €7300-€11,000 or $10,000-$16 000 in September 2011). The two Find and Treat components were also cost effective, even in unfavourable scenarios (mobile screening unit (for undiagnosed cases), £18,000-£26,000/QALY gained; case management support team, £4100-£6800/QALY gained). CONCLUSIONS: Both the screening and case management components of the Find and Treat service are likely to be cost effective in London. The cost effectiveness of the mobile screening unit in particular could be even greater than estimated, in view of the secondary effects of infection transmission and development of antibiotic resistance

Development of methods for the in-vitro assessment of the adipogenesis and immunogenicity of human multipotent mesenchymal stromal cells

Adult mesenchymal stromal cells (MSCs) have enormous potential in tissue engineering and regenerative medicine applications. MSC have also been reported to be immune-privileged. The aim of this study was to develop methods to test two related hypotheses. Firstly, that MSCs will not directly stimulate allogeneic lymphocytes in classical lymphocyte proliferation assays carried out over 5-7 days due to lack of expression of immune-regulatory molecules (CD40, CD80, CD86 and MHC Class-II) but may be capable of the stimulation of allogeneic lymphocytes when cultured over extended time periods that allow the indirect pathway of antigen presentation. Secondly, that following differentiation of MSCs into mature differentiated adipose cells, the cells would become immunogenic or increase their immunogenicity, as determined by the stimulation of allogeneic peripheral blood mononuclear cells in lymphocyte transformation assays. MSCs from 4 human bone marrow donors were isolated, expanded and characterised and shown to conform to the ISCT definition of MSC through FACs analysis of key antigen expression and trilineage differentiation. MSCs (from donors 1-3) were differentiated into adipocytes, and current methodology for assaying adipogenesis was evaluated. A new fluorescent microplate assay was developed using DAPI to normalise for cell number and Nile red to stain for intracellular lipids, to generate a ratio of adipogenesis. Peripheral blood mononuclear cells (PBMCs) from 6 volunteers were isolated, in-vitro assay conditions for performing lymphocyte transformation assays (LTAs) were optimised, and the duration of the assays extended to 16-21 days. It was shown that undifferentiated MSCs stimulated PBMCs in all except 2 out of 24 cases, with the highest stimulation typically post-day 7 with stimulation indices as high as 36 observed. It was shown that MSCs differentiated into adipocytes also stimulated PBMCs with higher stimulation indices observed in differentiated MSCs compared to the undifferentiated counterparts. It was concluded that MSC, whether undifferentiated or differentiated into adipose cells, are indeed capable of stimulating a proliferative response in allogeneic lymphocytes. Therefore, the use of allogeneic MSCs in the traditional engineering setting may be limited, and a cautious approach should be taken before allogeneic MSCs are used in the regeneration or creation of tissue replacements for clinical use.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Terminology and concepts of control and Fuzzy Logic

Viewgraphs on terminology and concepts of control and fuzzy logic are presented. Topics covered include: control systems; issues in the design of a control system; state space control for inverted pendulum; proportional-integral-derivative (PID) controller; fuzzy controller; and fuzzy rule processing

Fuzzy Description of Skin Lesions

We propose a system for describing skin lesions images based on a human perception model. Pigmented skin lesions including melanoma and other types of skin cancer as well as non-malignant lesions are used. Works on classification of skin lesions already exist but they mainly concentrate on melanoma. The novelty of our work is that our system gives to skin lesion images a semantic label in a manner similar to humans. This work consists of two parts: first we capture they way users perceive each lesion, second we train a machine learning system that simulates how people describe images. For the first part, we choose 5 attributes: colour (light to dark), colour uniformity (uniform to non-uniform), symmetry (symmetric to non-symmetric), border (regular to irregular), texture (smooth to rough). Using a web based form we asked people to pick a value of each attribute for each lesion. In the second part, we extract 93 features from each lesions and we trained a machine learning algorithm using such features as input and the values of the human attributes as output. Results are quite promising, especially for the colour related attributes, where our system classifies over 80 % of the lesions into the same semantic classes as humans