296 research outputs found

    Trading interactions for topology in scale-free networks

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    Scale-free networks with topology-dependent interactions are studied. It is shown that the universality classes of critical behavior, which conventionally depend only on topology, can also be explored by tuning the interactions. A mapping, γ=(γμ)/(1μ)\gamma' = (\gamma - \mu)/(1-\mu), describes how a shift of the standard exponent γ\gamma of the degree distribution P(q)P(q) can absorb the effect of degree-dependent pair interactions Jij(qiqj)μJ_{ij} \propto (q_iq_j)^{-\mu}. Replica technique, cavity method and Monte Carlo simulation support the physical picture suggested by Landau theory for the critical exponents and by the Bethe-Peierls approximation for the critical temperature. The equivalence of topology and interaction holds for equilibrium and non-equilibrium systems, and is illustrated with interdisciplinary applications.Comment: 4 pages, 5 figure

    Increased epidermal thickness and abnormal epidermal differentiation in keloid scars

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    Background: The pathogenesis underlying keloid formation is still poorly understood. Research has focused mostly on dermal abnormalities, while the epidermis has not yet been studied. Objectives: To identify differences within the epidermis of mature keloid scars compared with normal skin and mature normotrophic and hypertrophic scars. Methods: Rete ridge formation and epidermal thickness were evaluated in tissue sections. Epidermal proliferation was assessed using immunohistochemistry (Ki67, keratins 6, 16 and 17) and with an in vitro proliferation assay. Epidermal differentiation was evaluated using immunohistochemistry (keratin 10, involucrin, loricrin, filaggrin, SPRR2, SKALP), reverse-transcriptase polymerase chain reaction (involucrin) and transmission electron microscopy (stratum corneum). Results: All scars showed flattening of the epidermis. A trend of increasing epidermal thickness correlating to increasing scar abnormality was observed when comparing normal skin, normotrophic scars, hypertrophic scars and keloids. No difference in epidermal proliferation was observed. Only the early differentiation marker involucrin showed abnormal expression in scars. Involucrin was restricted to the granular layer in healthy skin, but showed panepidermal expression in keloids. Normotrophic scars expressed involucrin in the granular and upper spinous layers, while hypertrophic scars resembled normotrophic scars or keloids. Abnormal differentiation was associated with ultrastructural disorganization of the stratum corneum in keloids compared with normal skin. Conclusions: Keloids showed increased epidermal thickness compared with normal skin and normotrophic and hypertrophic scars. This was not due to hyperproliferation, but possibly caused by abnormal early terminal differentiation, which affects stratum corneum formation. Our findings indicate that the epidermis is associated with keloid pathogenesis and identify involucrin as a potential diagnostic marker for abnormal scarring

    Bisphosphonate-Associated Osteonecrosis of the Jaw: Are We Dealing with a Localized Non-Traditional Calciphylaxis?

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    The bisphosphonate (BP) family of drugs has been used as a vital component in cancer therapy and many other diseases. One of the main adverse effects related to (BP) is BP-associated osteonecrosis of the jaw (ONJ). Although this condition was first recognized in 2003, the pathophysiologic mechanism remains undefined. Our hypothesis is that ONJs clinical course and delayed wound healing is in part correlated to a localized non-traditional calciphylaxis. This effect is identified by the evidence of calcium deposition in the connective tissue and around small blood vessels in the soft tissues immediately adjacent to ONJ lesions. This phenomenon helps to fill gaps in the cascade of events which leads to soft tissue ischemia, necrosis, and non-healing ONJ lesions. Our finding adds to the current knowledge of the potential pathophysiologic mechanisms related to ONJ

    Agricultural policies exacerbate honeybee pollination service supply-demand mismatches across Europe

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    Declines in insect pollinators across Europe have raised concerns about the supply of pollination services to agriculture. Simultaneously, EU agricultural and biofuel policies have encouraged substantial growth in the cultivated area of insect pollinated crops across the continent. Using data from 41 European countries, this study demonstrates that the recommended number of honeybees required to provide crop pollination across Europe has risen 4.9 times as fast as honeybee stocks between 2005 and 2010. Consequently, honeybee stocks were insufficient to supply >90% of demands in 22 countries studied. These findings raise concerns about the capacity of many countries to cope with major losses of wild pollinators and highlight numerous critical gaps in current understanding of pollination service supplies and demands, pointing to a pressing need for further research into this issue

    The multifunctional roles of vegetated strips around and within agricultural fields : A systematic map protocol.

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    Background: Agriculture and agricultural intensification can have significant negative impacts on the environment, including nutrient and pesticide leaching, spreading of pathogens, soil erosion and reduction of ecosystem services provided by terrestrial and aquatic biodiversity. The establishment and management of vegetated strips adjacent to farmed fields (including various field margins, buffer strips and hedgerows) are key mitigation measures for these negative environmental impacts and environmental managers and other stakeholders must often make decisions about how best to design and implement vegetated strips for a variety of different outcomes. However, it may be difficult to obtain relevant, accurate and summarised information on the effects of implementation and management of vegetated strips, even though a vast body of evidence exists on multipurpose vegetated strip interventions within and around fields. To improve the situation, we describe a method for assembling a database of relevant research relating to vegetated strips undertaken in boreo-temperate farming systems (arable, pasture, horticulture, orchards and viticulture). Methods: We will search 13 bibliographic databases, 1 search engine and 37 websites for stakeholder organisations using a predefined and tested search string that focuses on a comprehensive list of vegetated strip synonyms. Non-English language searches in Danish, Finnish, German, Spanish, and Swedish will also be undertaken using a web-based search engine. We will screen search results at title, abstract and full text levels, recording the number of studies deemed non-relevant (with reasons at full text). A systematic map database that displays the meta-data (i.e. descriptive summary information about settings and methods) of relevant studies will be produced following full text assessment. The systematic map database will be displayed as a web-based geographical information system (GIS). The nature and extent of the evidence base will be discussed
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