3,133 research outputs found

    Intra-tumour signalling entropy determines clinical outcome in breast and lung cancer.

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    The cancer stem cell hypothesis, that a small population of tumour cells are responsible for tumorigenesis and cancer progression, is becoming widely accepted and recent evidence has suggested a prognostic and predictive role for such cells. Intra-tumour heterogeneity, the diversity of the cancer cell population within the tumour of an individual patient, is related to cancer stem cells and is also considered a potential prognostic indicator in oncology. The measurement of cancer stem cell abundance and intra-tumour heterogeneity in a clinically relevant manner however, currently presents a challenge. Here we propose signalling entropy, a measure of signalling pathway promiscuity derived from a sample's genome-wide gene expression profile, as an estimate of the stemness of a tumour sample. By considering over 500 mixtures of diverse cellular expression profiles, we reveal that signalling entropy also associates with intra-tumour heterogeneity. By analysing 3668 breast cancer and 1692 lung adenocarcinoma samples, we further demonstrate that signalling entropy correlates negatively with survival, outperforming leading clinical gene expression based prognostic tools. Signalling entropy is found to be a general prognostic measure, valid in different breast cancer clinical subgroups, as well as within stage I lung adenocarcinoma. We find that its prognostic power is driven by genes involved in cancer stem cells and treatment resistance. In summary, by approximating both stemness and intra-tumour heterogeneity, signalling entropy provides a powerful prognostic measure across different epithelial cancers

    Symmetry Nonrestoration in a Resummed Renormalized Theory at High Temperature

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    We reinvestigate the interesting phenomenon of symmetry nonrestoration at high temperature in the multifield O(N_1) X O(N_2) model. We apply modified self-consistent resummation (MSCR) in order to obtain the scalar dressed masses and find in what circumstances a resummed multifield theory which has symmetry (non)restoration can be renormalized. It is shown that, aside from the consistency of the MSCR method, the basic ingredient that guarantees the renormalization of a multifield model within a resummation approach is the T^2 mass behavior of field theory at high temperature.Comment: 14 pages, 1 ps figure, revtex, Phys. Rev. D versio

    Temperature effects on the magnetization of quasi-one-dimensional Peierls distorted materials

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    It is shown that temperature acts to disrupt the magnetization of Peierls distorted quasi-one-dimensional materials (Q1DM). The mean-field finite temperature phase diagram for the field theory model employed is obtained by considering both homogeneous and inhomogeneous condensates. The tricritical points of the second order transition lines of the gap parameter and magnetization are explicitly calculated. It is also shown that in the absence of an external static magnetic field the magnetization is always zero, at any temperature. As expected, temperature does not induce any magnetization effect on Peierls distorted Q1DM.Comment: 11 pages, 2 figure

    Performance of traditional cooperatives: the Portuguese Douro wine cooperatives

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    Globalization is challenging the very core of cooperative governance and ownership decision, especially in Southern European countries, like Portugal, where a large number of producers are organized in traditional and Mediterranean-style agricultural cooperatives. This paper analyses the effects of governance and control variables related with size over two alternative indicators of performance: revenues transferred to members/patrons and capital structure. The results suggest that these cooperatives have difficulties being sustainable in the more competitive global wine markets, if they follow, essentially, a practice of maximum patronage refund, reducing their capacity to improve leverage and to finance more profitable, but risky, long run investments.Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Q13, D22, L25,

    Manager Power, Member Behavior and Capital Structure: Portuguese Douro Wine Cooperatives

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    Leverage is one of the most important financial factors to the survival and viability of agricultural cooperatives (e.g., wine cooperatives) during a period of intense competition. Leverage is influenced both by the behavior of managers and cooperative members. An empirical study for the Douro Demarcated Region Wine Cooperatives (DDRWC) supports the hypothesis that managers have a positive influence in the determination of the equity/total assets ratio and that individualistic behavior of cooperative members has a negative influence in the value of this ratio. This paper suggests that there may be value in reconsidering cooperatives in the context of a so-called Mediterranean model.Agribusiness, Agricultural cooperatives, governance, behavior and leverage,
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