186,985 research outputs found
Active noise control in finite length ducts
No full textA simple technique for the active control of sound in ducts, initially suggested by Olson and May [1], is investigated in detail. A simple, "virtual earth" principle, feedback loop is used to drive the sound pressure to a minimum at a microphone placed close to a loudspeaker in the duct wall. This produces a reflection of downstream travelling plane waves. A detailed investigation of the loudspeaker near field has enabled the optimum position of the microphone to be identified. The system is shown to be especially effective at the frequencies of the longitudinal duct resonances, where the acoustic response of the duct produces a high loop gain. Results are presented which show a reduction of up to 20 dB in the amplitude of low frequency broadband noise at a position downstream of the cancelling source.</p
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
A study of zinc transporter 1 and its role in Type 3 Haemochromatosis
No full textHereditary haemochromatosis is an autosomal recessive disorder of iron metabolism, characterised by increased iron absorption and progressive iron accumulation particularly in the liver. It has been shown that hepatocytes can acquire iron in two forms; transferrin-bound iron (TBI) and non-transferrin-bound iron (NTBI)1. Known transporters of NTBI into the cell include DMT1 and ZIP14, and FPN is the only transporter known to export iron.
The aims of this study were to characterize the zinc transporter, ZnT-1 and determine whether it is involved in iron transport, specifically as an exporter.
There was a decrease in mRNA expression of the short untranslated isoform of ZnT-1 in double mutant (Hfe -/- and TfR2 Y245X) mouse liver, a trend also seen in TfR1 and Hamp. The long untranslated isoform, however, was significantly higher in the iron-deficient mice as was expression of TfR1 and Ferroportin. Iron and zinc efflux was measured in cells over-expressing ZnT-1 and control cells. There was no difference between over-expressed and control cells in iron efflux. However, at 60 min, over-expressed cells had significantly more zinc efflux than control cells. More zinc than iron was released from the cell.
The results of this study do not support the hypotheses that (i) ZnT-1 reduces intracellular cytoplasmic iron concentration by promoting efflux and 2 ZnT-1 is down-regulated in iron-loaded cells
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
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
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Edward P. Wimberly, ITC, July 2011
No full textThis video is a conversation with Dr. Edward P. Wimberly. Dr. Wimberly talks about his book, "No Shame in Wesley's Gospel: A Twenty-First Century Pastoral Gospel". Brad Ost, AUC Woodruff Library, is the interviewer
- …
