715 research outputs found

    Crisis, farming and community

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    In 2001, the UK was hit by Foot and Mouth Disease (FMD) precipitating one of the biggest crises ever to affect the UK farming system. The crisis unfolded as a series of information and communication problems, from government to farmers and from farmers to farmers, with consequences for action in a time of crisis, social support, and the maintenance of community. What happens to a farming community during such a crisis? When the countryside shuts down, and no one can enter or leave the farm, how can information be disseminated? As methods of dealing with the disease change rapidly, as happened in this crisis, how can information be delivered in a timely and coordinated manner? To explore these questions, data have been gathered from reports and writing about the crisis, and from interviews with Cumbrian farmers. Although we will address throughout the discussion the multiple information channels used by farmers, this paper focuses on the role of information and communication technologies (ICTs) during the crisis, notably a community networking initiative known as Pentalk. We conclude with a look at the current role of Pentalk in the farming community, and with discussion of how networks such as these can help during crises in which there are significant needs for information and communication management

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    Level and pattern of overstory retention shape the abundance and long-term dynamics of natural and created snags

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    Standing dead trees, or snags, serve myriad functions in natural forests, but are often scarce in forests managed for timber production. Variable retention (VR), the retention of live and dead trees through harvest, has been adopted globally as a less intensive form of regeneration harvest. In this study, we explore how two key elements of VR systems — level (amount) and spatial pattern of live-tree retention — affect the carryover and post-harvest dynamics of natural and artificially created snags. We present nearly two decades of data from the DEMO Study, a regional-scale experiment in VR harvests of Douglas-fir-dominated forests in the Pacific Northwest. Snag losses to harvest were greater at 15 than at 40% retention (67 vs. 47% declines in density) and greater in dispersed than in aggregated treatments (64 vs. 50% declines). Densities of hard and tall (≄5 m) snags were particularly sensitive to low-level dispersed retention, declining by 76 and 81%, respectively. Despite these losses, post-harvest densities correlated with pre-harvest densities for most snag size and decay classes. In contrast to initial harvest effects, snag densities changed minimally over the post-harvest period (years 1 to 18 or 19), with low rates of recruitment offsetting low rates of loss. Post-harvest survival of snags was greater at 15 than at 40% retention (79 vs. 69%), as were rates of decay (68 vs. 52% of hard snags transitioned to soft). However, pattern had no effect on either process. Snag recruitment did not vary with retention level or pattern at the scale of the 13-ha harvest unit, but was several-fold greater in the 1-ha aggregates (14.3–27.8 snags ha -1) than in the corresponding dispersed treatments (4.2–5.3 snags ha -1). Snag size (diameter) distributions showed greater change in dispersed than in aggregated treatments, reflecting greater loss of smaller snags and recruitment biased toward larger snags. Created snags showed uniformly high survival (97%), irrespective of treatment, but rates of decay were greater at lower retention. If a goal of VR is to sustain snag abundance and diversity through harvest, emphasis should be placed on minimizing initial losses, either by reducing the intensity of felling in areas of dispersed retention or locating forest aggregates in areas of greater initial snag density, diversity, or incipient decay

    Explaining the unobserved: why quantum mechanics is not only about information

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    A remarkable theorem by Clifton, Bub and Halvorson (2003)(CBH) characterizes quantum theory in terms of information--theoretic principles. According to Bub (2004, 2005) the philosophical significance of the theorem is that quantum theory should be regarded as a ``principle'' theory about (quantum) information rather than a ``constructive'' theory about the dynamics of quantum systems. Here we criticize Bub's principle approach arguing that if the mathematical formalism of quantum mechanics remains intact then there is no escape route from solving the measurement problem by constructive theories. We further propose a (Wigner--type) thought experiment that we argue demonstrates that quantum mechanics on the information--theoretic approach is incomplete.Comment: 34 Page

    Burkholderia BcpA mediates biofilm formation independently of interbacterial contact dependent growth inhibition

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    Contact dependent growth inhibition (CDI) is a phenomenon in which Gram-negative bacteria use the toxic C-terminus of a large surface-exposed exoprotein to inhibit the growth of susceptible bacteria upon cell-cell contact. Little is known about when and where bacteria express the genes encoding CDI system proteins and how these systems contribute to the survival of bacteria in their natural niche. Here we establish that, in addition to mediating interbacterial competition, the Burkholderia thailandensis CDI system exoprotein BcpA is required for biofilm development. We also provide evidence that the catalytic activity of BcpA and extracellular DNA are required for the characteristic biofilm pillars to form. We show using a bcpA-gfp fusion that within the biofilm, expression of the CDI system-encoding genes is below the limit of detection for the majority of bacteria and only a subset of cells express the genes strongly at any given time. Analysis of a strain constitutively expressing the genes indicates that native expression is critical for biofilm architecture. Although CDI systems have so far only been demonstrated to be involved in interbacterial competition, constitutive production of the system’s immunity protein in the entire bacterial population did not alter biofilm formation, indicating a CDI-independent role for BcpA in this process. We propose, therefore, that bacteria may use CDI proteins in cooperative behaviors, like building biofilm communities, and in competitive behaviors that prevent non-self bacteria from entering the community
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