117,304 research outputs found
Atomic force microscopy study of DNA deposited on poly-L-ornithine coated mica
No full textAnalyses of individual biomolecules, like DNA, or DNA–protein
complexes, via atomic force microscopy, require ‘gentle’ methods
to immobilize DNA on surfaces, which allow the ensemble of
molecules to adopt conformations dictated primarily by their
physical characteristics, and which possibly permit the use of a
wide selection of buffers. We show that poly-l-ornithine-coated
mica is a good substrate for fast, reliable deposition of DNA for
wet or dry imaging. The surface firmly secures DNA, which
retains the B-form helical rise (0.34 nm bp−1). The conformations
of DNA that result are reminiscent of three-dimensional
random coils projected on to a plane. The contrast is good,
especially in solution, and buffers with physiological concentrations
of salt with or without divalent cations may be used. This
is important for comparison of scanning probe microscopy
results with those obtained by different techniques
LCA to support the integration of Reuse strategies during building design: advancements and gaps
No full textDNA Compaction by the Nuclear Factor-Y
No full textAbstractThe nuclear factor-Y (NF-Y), a trimeric, CCAAT-binding transcriptional activator with histone-like subunits, was until recently considered a prototypical promoter transcription factor. However, recent in vivo chromatin immunoprecipitation assays associated with microarray methodologies (chromatin immunoprecipitation on chip experiments) have indicated that a large portion of target sites (40%–50%) are located outside of core promoters. We applied the tethered particle motion technique to the major histocompatibility complex class II enhancer-promoter region to characterize i), the progressive compaction of DNA due to increasing concentrations of NF-Y, ii), the role of specific subunits and domains of NF-Y in the process, and iii), the interplay between NF-Y and the regulatory factor-X, which cooperatively binds to the X-box adjacent to the CCAAT box. Our study shows that NF-Y has histone-like activity, since it binds DNA nonspecifically with high affinity to compact it. This activity, which depends on the presence of all trimer subunits and of their glutamine-rich domains, seems to be attenuated by the transcriptional cofactor regulatory factor-X. Most importantly NF-Y-induced DNA compaction may facilitate promoter-enhancer interactions, which are known to be critical for expression regulation
Active House: Smart Nearly Zero Energy Buildings
No full textThe book provides an overview of the Active House (AH) vision, intended as a building design method “beyond” the passive approach for buildings of the future that will be more and more connected, smart and innovative. It offers a novel philosophical design approach in which buildings, new or renovated, are in balance with natural, renewable energies and become “concentrators-distributors” of energies instead of being consumers of resources. The book is composed of five chapters, providing information on fundamental aspects of innovations toward resource-efficient buildings, as well as case studies presenting the concept in practice. It demonstrates that a completely new design approach is possible, and that a turning point has been reached. Lastly, it shows how the AH Alliance, along with designers, institutions, industries and academies, is bringing a breath of fresh air to the world of construction
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Carbon nets: structural reinforcement and seismic assessment of existing buildings with carbon strands (Cabkoma)
No full textSquare Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Africa, Ideas for a sustainable future. Leapfrog Strategies: Design for social and system innovation for sustainability in South Africa, Kenya, Botswana, Ghana
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