Finding communities in sparse networks

Spectral algorithms based on matrix representations of networks are often used to detect communities but classic spectral methods based on the adjacency matrix and its variants fail to detect communities in sparse networks. New spectral methods based on non-backtracking random walks have recently been introduced that successfully detect communities in many sparse networks. However, the spectrum of non-backtracking random walks ignores hanging trees in networks that can contain information about the community structure of networks. We introduce the reluctant backtracking operators that explicitly account for hanging trees as they admit a small probability of returning to the immediately previous node unlike the non-backtracking operators that forbid an immediate return. We show that the reluctant backtracking operators can detect communities in certain sparse networks where the non-backtracking operators cannot while performing comparably on benchmark stochastic block model networks and real world networks. We also show that the spectrum of the reluctant backtracking operator approximately optimises the standard modularity function similar to the flow matrix. Interestingly, for this family of non- and reluctant-backtracking operators the main determinant of performance on real-world networks is whether or not they are normalised to conserve probability at each node.Comment: 11 pages, 4 figure

Diversity, Disadvantage and Differential Outcomes: An analysis of Samoan students narratives of schooling

Social justice discourses, particularly those attentive to the politics of difference, suggest that the perspectives of least-advantaged groups need to be taken into account when endeavouring to realise social justice in education for these groups. In this paper, we analyse narratives on schooling produced by one cohort of least-advantaged students, namely Samoan students attending state-designated disadvantaged secondary schools in Queensland, Australia. Specifically, the narratives of educational disadvantage provided by Samoan students are analysed. The focus is on 'the what' (the knowledge to be transmitted) and 'the how' (the teacher-student relations) of pedagogy in state-designated disadvantaged schools. Attention is paid to the contradictory and ambivalent discourses inherent in these narratives, particularly in terms of realising socially just pedagogic practices

Negotiation and Decision Making to Develop a Public-Private-Partnership: A Case-Based Approach

Decision making in practice varies from theoretical models and processes. Unpredictable and ill-structured operating conditions require dynamic resolution approaches underpinned by effective negotiation and decision making strategies to support collaborative work and partnerships. This short paper evaluates negotiation strategies and decision making approaches adopted to reach agreement for a unique Public-Private-Partnership. It examines how decision criteria were formulated and decision rules generated through negotiation process executions, and uncertainties addressed by adopting multi-criteria and evidential reasoning approach. Findings are presented to help improve business performance in future PPPs by making effective decisions based on experience gained through past process execution

Pharmaceutical Industry Collaborations: Delivering Joint-Working Partnerships with the NHS

The primary focus of this paper is to evaluate how pharmaceutical organisations in the United Kingdom deliver Joint Working initiatives in partnership with the healthcare service. Joint Working represents the most formalised and transparent mechanism for cooperation between the industry and the National Health Service (NHS). The research evaluates the level of capability that organisations ‘desire’ to deliver collaborative initiatives, and the degree to which they possess the competencies to deliver them. A pilot study is conducted that adopts a mixed method research approach using secondary data and focus group analyses, interviews, and a survey. The findings present a comprehensive range of benefits that would appear to represent a compelling rationale for enhanced capability in Joint Working within the healthcare sector

Fibronectin peptides and murine embryonic stem cells : an in vitro study

Murine embryonic stem cells are cells that are obtained from the inner cell mass of the embryo blastocyst at day 3.5. These cells have the novel capability of differentiating into almost any cell lineage in the mammal and this characteristic has resulted in them being referred to as pluripotent. Fibronectin is involved in a number of different functions including differentiation, growth, migration and the adhesion of cells. In addition it is well known to interact with the extracellular matrix. Fibronectin also has an essential role to play in early development of the embryo as studies have shown that knocking out either fibronectin or its primary receptor eg 51 integrin receptor is lethal to the developing embryo. The section of fibronectin identified as being essential for binding and activation of 51 integrin receptor has been identified as the 9th and 10th type III fibronectin domain. This peptide of fibronectin has subsequently been generated. In this study, the effect of this fibronectin peptide on murine embryonic stem cells was examined. In particular it was identified that the generation of 2-D orientated fibronectin peptide displays in no way enhances the cell attachment potential of the fibronectin peptides. The optimal conformation of the peptides for the attachment of embryonic stem cell colonies was identified as being the dimeric form of the peptide. The fact that these fibronectin peptides have no effect on the proliferation of embryonic stem cells was also determined. There was an apparent morphological change in embryonic stem cells grown on the fibronectin peptides. These embryonic stem cells were flatter and reminiscent of differentiated embryonic stem cells. This occurred even when the embryonic stem cells were cultured in the presence of LIF, the cytokine essential to maintain embryonic stem cells in a state of self renewal. Alkaline phosphatase staining confirmed that while there was a morphological change the embryonic stem cells maintained their undifferentiated state when grown on fibronectin peptides in the presence of LIF. Finally Quantitative Polymerase Chain Reaction was carried out in an attempt to ascertain why there appeared to be a morphological change in embryonic stem cells grown on fibronectin peptides as opposed to embryonic stem cells grown on gelatin controls. In the presence of LIF, there was a transient increase in the number of Oct-4, Brachyury and Nestin transcripts. Up regulation of these genes is known in some cases to come from a pro differentiation signal. However concomitant with these transcriptional up regulations, the levels of Nanog, the gene well known to resist and/or reverse changes in gene expression states in embryonic stem cells also increased upon growth on fibronectin peptides. It is possible that in the presence of LIF, Nanog increases to inhibit the differentiation inducing signals produced by interaction of the fibronectin peptides with the 51 integrin receptor. When grown in complete media containing foetal calf serum in the absence of LIF, there were no obvious transcriptional changes that gave an indication to which, if any, lineage the fibroenctin peptides may be instructing the embryonic stem cells to differentiate into. Upon using serum replacement media as opposed to foetal calf serum and allowing the embryonic stem cells to differentiate more obvious transcriptional changes were observed. ES cells grown on the fibronectin peptides appeared to be inhibited from increasing the levels of transcripts with known roles in cardiac and neuroectodermal differentiation. However there was a transient increase in the levels of FoxA2, a gene involved in the differentiation of embryonic stem cells into endodermal tissue. This increase was shortly followed by a significant decrease in the levels of transcripts when grown on the fibronectin peptides as opposed to gelatin controls. Importantly it appears that allowing the differentiation of embryonic stem cells to occur in a monolayer instead of the classically used embryoid bodies could potentially be used as an alternative model to study embryonic stem cell differentiation

An end-to-end convolutional selective autoencoder approach to Soybean Cyst Nematode eggs detection

This paper proposes a novel selective autoencoder approach within the framework of deep convolutional networks. The crux of the idea is to train a deep convolutional autoencoder to suppress undesired parts of an image frame while allowing the desired parts resulting in efficient object detection. The efficacy of the framework is demonstrated on a critical plant science problem. In the United States, approximately $1 billion is lost per annum due to a nematode infection on soybean plants. Currently, plant-pathologists rely on labor-intensive and time-consuming identification of Soybean Cyst Nematode (SCN) eggs in soil samples via manual microscopy. The proposed framework attempts to significantly expedite the process by using a series of manually labeled microscopic images for training followed by automated high-throughput egg detection. The problem is particularly difficult due to the presence of a large population of non-egg particles (disturbances) in the image frames that are very similar to SCN eggs in shape, pose and illumination. Therefore, the selective autoencoder is trained to learn unique features related to the invariant shapes and sizes of the SCN eggs without handcrafting. After that, a composite non-maximum suppression and differencing is applied at the post-processing stage.Comment: A 10 pages, 8 figures International Conference on Machine Leaning(ICML) Submissio

Embedding Innovation: How Large Organizations Can Succeed at Innovation in the Long Term

Making innovation stick has proven difficult to many large organizations. The challenge these organizations face is to turn innovation from a buzzword into a systemic and widely distributed competency. This study explored how to do this by asking the question “How might large organizations enable and nurture innovation over the long term?” The study used a combination of research methods and adopted a design approach to answering the question. Research methods included literature review, case studies, surveys, semi-structured interviews, innovation canvassing and foresighting. The research identified that in order to embed innovation into an organization’s DNA, that organization must have a strong innovation orientation, and must demonstrate aptitude in five critical areas: strategy, culture, process, portfolio and scalability. These findings were used to propose a roadmap to innovation for the City of Toronto’s Chief Corporate Officer; one that embodies the characteristics of successful, long-term approaches to innovation that would allow the organization to transform itself into a more innovative organization

Thermal Abundances of Heavy Particles

Matsumoto and Yoshimura [hep-ph/9910393] have argued that there are loop corrections to the number density of heavy particles (in thermal equilibrium with a gas of light particles) that are not Boltzmann suppressed by a factor of e^(-M/T) at temperatures T well below the mass M of the heavy particle. We argue, however, that their definition of the number density does not correspond to a quantity that could be measured in a realistic experiment. We consider a model where the heavy particles carry a conserved U(1) charge, and the light particles do not. The fluctuations of the net charge in a given volume then provide a measure of the total number of heavy particles in that same volume. We show that these charge fluctuations are Boltzmann suppressed (to all orders in perturbation theory). Therefore, we argue, the number density of heavy particles is also Boltzmann suppressed.Comment: 9 pages, 1 figure; minor improvements in revised versio

Slowly co-fluctuating gene expression patterns are heritable and associated with stress resistance and improved productivity in CHO cell line development

Please click Additional Files below to see the full abstract