Climate geoengineering: issues of path-dependence and socio-technical lock-in

As academic and policy interest in climate geoengineering grows, the potential irreversibility of technological developments in this domain has been raised as a pressing concern. The literature on socio-technical lock-in and path dependence is illuminating in helping to situate current concerns about climate geoengineering and irreversibility in the context of academic understandings of historical socio-technical development and persistence. This literature provides a wealth of material illustrating the pervasiveness of positive feedbacks of various types (from the discursive to the material) leading to complex socio-technical entanglements which may resist change and become inflexible even in the light of evidence of negative impacts. With regard to climate geoengineering, there are concerns that geoengineering technologies might contribute so-called ‘carbon lock-in’, or become irreversibly ‘locked-in’ themselves. In particular, the scale of infrastructures that geoengineering interventions would require, and the issue of the so-called ‘termination effect’ have been discussed in these terms. Despite the emergent and somewhat ill-defined nature of the field, some authors also suggest that the extant framings of geoengineering in academic and policy literatures may already demonstrate features recognizable as forms of cognitive lock-in, likely to have profound implications for future developments in this area. While the concepts of path-dependence and lock-in are the subject of ongoing academic critique, by drawing analytical attention to these pervasive processes of positive feedback and entanglement, this literature is highly relevant to current debates around geoengineering

Assembly complexity of prokaryotic genomes using short reads

<p>Abstract</p> <p>Background</p> <p>De Bruijn graphs are a theoretical framework underlying several modern genome assembly programs, especially those that deal with very short reads. We describe an application of de Bruijn graphs to analyze the global repeat structure of prokaryotic genomes.</p> <p>Results</p> <p>We provide the first survey of the repeat structure of a large number of genomes. The analysis gives an upper-bound on the performance of genome assemblers for <it>de novo </it>reconstruction of genomes across a wide range of read lengths. Further, we demonstrate that the majority of genes in prokaryotic genomes can be reconstructed uniquely using very short reads even if the genomes themselves cannot. The non-reconstructible genes are overwhelmingly related to mobile elements (transposons, IS elements, and prophages).</p> <p>Conclusions</p> <p>Our results improve upon previous studies on the feasibility of assembly with short reads and provide a comprehensive benchmark against which to compare the performance of the short-read assemblers currently being developed.</p

Innovation, low energy buildings and intermediaries in Europe: systematic case study review

As buildings throughout their lifecycle account for circa 40% of total energy use in Europe, reducing energy use of the building stock is a key task. This task is, however, complicated by a range of factors, including slow renewal and renovation rates of buildings, multiple non- coordinated actors, conservative building practices, and limited competence to innovate. Drawing from academic literature published during 2005-2015, this article carries out a systematic review of case studies on low energy innovations in the European residential building sector, analysing their drivers. Specific attention is paid to intermediary actors in facilitating innovation processes and creating new opportunities. The study finds that qualitative case study literature on low energy building innovation has been limited, particularly regarding the existing building stock. Environmental concerns, EU, national and local policies have been the key drivers; financial, knowledge and social sustainability and equity drivers have been of modest importance; while design, health and comfort, and market drivers have played a minor role. Intermediary organisations and individuals have been important through five processes: (1) facilitating individual building projects, (2) creating niche markets, (3) implementing new practices in social housing stock, (4) supporting new business model creation, and (5) facilitating building use post construction. The intermediaries have included both public and private actors, while local authority agents have acted as intermediaries in several cases

A fully resolved consensus between fully resolved phylogenetic trees

Nowadays, there are many phylogeny reconstruction methods, each with advantages and disadvantages. We explored the advantages of each method, putting together the common parts of trees constructed by several methods, by means of a consensus computation. A number of phylogenetic consensus methods are already known. Unfortunately, there is also a taboo concerning consensus methods, because most biologists see them mainly as comparators and not as phylogenetic tree constructors. We challenged this taboo by defining a consensus method that builds a fully resolved phylogenetic tree based on the most common parts of fully resolved trees in a given collection. We also generated results showing that this consensus is in a way a kind of 'median' of the input trees; as such it can be closer to the correct tree in many situations.5126928

Long-term effects of darusentan on left-ventricular remodelling and clinical outcomes in the Endothelin(A) Receptor Antagonist Trial in Heart Failure (EARTH): randomised, double-blind, placebo-controlled trial

BACKGROUND: Endothelin-receptor blockade provides haemodynamic benefit in experimental and clinical heart failure. We aimed to measure the effects of long-term endothelin-blockade on left-ventricular (LV) remodelling and clinical outcomes in patients with chronic heart failure. METHODS: 642 patients with chronic heart failure were assigned the oral endothelin(A)-antagonist darusentan at 10, 25, 50, 100, or 300 mg daily or placebo for 24 weeks in addition to standard therapy in a randomised, double-blind, placebo-controlled trial. In the 50-300 mg groups, darusentan was uptitrated over 6 weeks. Primary endpoint was change in LV end-systolic volume (LVESV) at 24 weeks from baseline, measured by MRI. All patients for whom assessable MRI scans were available at baseline and follow-up were included in the analysis. FINDINGS: Darusentan was well tolerated. LVESV could be assessed in 485 (76%) patients with paired MRI data at baseline and 6 months. The change in LVESV was not significantly different from that with placebo at any dose (mean difference from placebo 1.27 mL [95% CI -9.9 to 12.4] with 10 mg dose, -1.84 mL [-13.0 to 9.3] with 25 mg, -5.68 mL [-16.9 to 5.6] with 50 mg, -4.05 mL [-15.5 to 7.4] with 100 mg, and -4.34 mL [-15.7 to 7.0] with 300 mg). Heart failure worsened in 71 (11.1%) patients, and 30 (4.7%) died during the study with no difference between groups. INTERPRETATION: Endothelin(A) blockade with darusentan did not improve cardiac remodelling or clinical symptoms or outcomes in patients with chronic heart failure receiving an angiotensin-converting-enzyme inhibitor, beta blocker, or aldosterone antagonist. Thus, endothelin(A) blockade is unlikely to be useful as an add-on treatment in such patients