220 research outputs found
Citation analysis may severely underestimate the impact of clinical research as compared to basic research
Background: Citation analysis has become an important tool for research
performance assessment in the medical sciences. However, different areas of
medical research may have considerably different citation practices, even
within the same medical field. Because of this, it is unclear to what extent
citation-based bibliometric indicators allow for valid comparisons between
research units active in different areas of medical research.
Methodology: A visualization methodology is introduced that reveals
differences in citation practices between medical research areas. The
methodology extracts terms from the titles and abstracts of a large collection
of publications and uses these terms to visualize the structure of a medical
field and to indicate how research areas within this field differ from each
other in their average citation impact.
Results: Visualizations are provided for 32 medical fields, defined based on
journal subject categories in the Web of Science database. The analysis focuses
on three fields. In each of these fields, there turn out to be large
differences in citation practices between research areas. Low-impact research
areas tend to focus on clinical intervention research, while high-impact
research areas are often more oriented on basic and diagnostic research.
Conclusions: Popular bibliometric indicators, such as the h-index and the
impact factor, do not correct for differences in citation practices between
medical fields. These indicators therefore cannot be used to make accurate
between-field comparisons. More sophisticated bibliometric indicators do
correct for field differences but still fail to take into account within-field
heterogeneity in citation practices. As a consequence, the citation impact of
clinical intervention research may be substantially underestimated in
comparison with basic and diagnostic research
Globalisation of science in kilometres
The ongoing globalisation of science has undisputedly a major impact on how
and where scientific research is being conducted nowadays. Yet, the big picture
remains blurred. It is largely unknown where this process is heading, and at
which rate. Which countries are leading or lagging? Many of its key features
are difficult if not impossible to capture in measurements and comparative
statistics. Our empirical study measures the extent and growth of scientific
globalisation in terms of physical distances between co-authoring researchers.
Our analysis, drawing on 21 million research publications across all countries
and fields of science, reveals that contemporary science has globalised at a
fairly steady rate during recent decades. The average collaboration distance
per publication has increased from 334 kilometres in 1980 to 1553 in 2009.
Despite significant differences in globalisation rates across countries and
fields of science, we observe a pervasive process in motion, moving towards a
truly interconnected global science system
The Samaritan ‘brought him to an inn’: Revisiting πανδοχεῖον in Luke 10:34
This article traces the meaning of κατάλυμά and πανδοχεῖον in available Roman-Egypt papyri, the LXX, early-Jewish literature, and Greek writings to determine the meaning of πανδοχεῖον [inn] used in Luke 10:34. It is argued that a lexical study of κατάλυμά and πανδοχεῖον and available information on travel in the ancient world indicate that there is no evidence for the so-called non-commercial inns in the ancient world and that commercial inns and innkeepers, in principle, were all ‘bad’. In conclusion, the implications of this understanding of πανδοχεῖον and πανδοκεύς (Lk 10:34, 35) for the possible intended meaning of the parable are discussed, a conclusion that begs further research regarding the identity of the protagonist in the parable
The Leiden Ranking 2011/2012: Data collection, indicators, and interpretation
The Leiden Ranking 2011/2012 is a ranking of universities based on
bibliometric indicators of publication output, citation impact, and scientific
collaboration. The ranking includes 500 major universities from 41 different
countries. This paper provides an extensive discussion of the Leiden Ranking
2011/2012. The ranking is compared with other global university rankings, in
particular the Academic Ranking of World Universities (commonly known as the
Shanghai Ranking) and the Times Higher Education World University Rankings.
Also, a detailed description is offered of the data collection methodology of
the Leiden Ranking 2011/2012 and of the indicators used in the ranking. Various
innovations in the Leiden Ranking 2011/2012 are presented. These innovations
include (1) an indicator based on counting a university's highly cited
publications, (2) indicators based on fractional rather than full counting of
collaborative publications, (3) the possibility of excluding non-English
language publications, and (4) the use of stability intervals. Finally, some
comments are made on the interpretation of the ranking, and a number of
limitations of the ranking are pointed out
Third Dredge-up in Low Mass Stars: Solving the LMC Carbon Star Mystery
A long standing problem with asymptotic giant branch (AGB) star models has
been their inability to produce the low-luminosity carbon stars in the Large
and Small Magellanic Clouds. Dredge-up must begin earlier and extend deeper. We
find this for the first time in our models of LMC metallicity. Such features
are not found in our models of SMC metallicity. The fully implicit and
simultaneous stellar evolution code STARS has been used to calculate the
evolution of AGB stars with metallicities of Z=0.008 and Z=0.004, corresponding
to the observed metallicities of the Large and Small Magellanic Clouds,
respecitively. Third dredge-up occurs in stars of 1Msol and above and carbon
stars were found for models between 1Msol and 3Msol. We use the detailed models
as input physics for a population synthesis code and generate carbon star
luminosity functions. We now find that we are able to reproduce the carbon star
luminosity function of the LMC without any manipulation of our models. The SMC
carbon star luminosity function still cannot be produced from our detailed
models unless the minimum core mass for third dredge-up is reduced by 0.06Msol.Comment: 6 pages, 5 figures. Accepted for publication in MNRA
Is green space in the living environment associated with people's feelings of social safety?
Abstract.
The authors investigate whether the percentage of green space in people's living environ-
ment affects their feelings of social safety positively or negatively. More specifically they investigate
the extent to which this relationship varies between urban and rural areas, between groups in the
community that can be identified as more or less vulnerable, and the extent to which different types of
green space exert different influences. The study includes 83736 Dutch citizens who were interviewed
about their feelings of social safety. The percentage of green space in the living environment of each
respondent was calculated, and data analysed by use of a three-level latent variable model, controlled
for individual and environmental background characteristics. The analyses suggest that more green
space in people's living environment is associated with enhanced feelings of social safetyöexcept in
very strongly urban areas, where enclosed green spaces are associated with reduced feelings of social
safety. Contrary to the common image of green space as a dangerous hiding place for criminal activity
which causes feelings of insecurity, the results suggest that green space generally enhances feelings of
social safety. The results also suggest, however, that green space in the most urban areas is a matter
of concern with respect to social safety.
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MELK is an oncogenic kinase essential for mitotic progression in basal-like breast cancer cells
Despite marked advances in breast cancer therapy, basal-like breast cancer (BBC), an aggressive subtype of breast cancer usually lacking estrogen and progesterone receptors, remains difficult to treat. In this study, we report the identification of MELK as a novel oncogenic kinase from an in vivo tumorigenesis screen using a kinome-wide open reading frames (ORFs) library. Analysis of clinical data reveals a high level of MELK overexpression in BBC, a feature that is largely dependent on FoxM1, a master mitotic transcription factor that is also found to be highly overexpressed in BBC. Ablation of MELK selectively impairs proliferation of basal-like, but not luminal breast cancer cells both in vitro and in vivo. Mechanistically, depletion of MELK in BBC cells induces caspase-dependent cell death, preceded by defective mitosis. Finally, we find that Melk is not required for mouse development and physiology. Together, these data indicate that MELK is a normally non-essential kinase, but is critical for BBC and thus represents a promising selective therapeutic target for the most aggressive subtype of breast cancer. DOI: http://dx.doi.org/10.7554/eLife.01763.00
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