1,720,980 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Full text linkWe 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
Clinical aggressiveness of incidental and non-incidental thyroid cancer.
No full textBACKGROUND: With the increasing use of thyroid ultrasound, the recognition of
thyroid nodules in a large proportion of apparently healthy subjects has become
common. Because also the papillary thyroid microcarcinomas (PTMC) are being
increasingly discovered, it is important to ascertain whether PTMC may exhibit
heterogenous clinical features, associated with different aggressiveness.
AIM: We retrospectively examined 122 subjects [98 female (80.3%), and 24 male
(19.7%)] with thyroid cancer to find potential clinical and pathological findings
that could be predictive of clinically aggressive behavior.
RESULTS: Twenty of the 31 patients with true incidental cancer (64.5%) in
comparison to 20 of the 91 patients with non-incidental cancer (21.9%) had a
diameter <10 mm, and this difference was statistically significant (p<0.0001).
There was a statistically significant association between size and invasiveness
because 19.3% of invasive cancers were <10 mm whereas 44.6% of non-invasive
cancers were <10 mm (p=0.005). The relationship between incidental discovery and
invasiveness was also evaluated, but the proportion of incidental invasive cancer
(19.3%) was not significantly different from that of incidental non-invasive
cancer (30.8%). In the multivariate analysis, only size <10 mm (odds ratio=0.35,
p=0.013) and papillary vs other histotypes (odds ratio=0.35, p=0.04) were
statistically significant protective factors against invasiveness.
CONCLUSIONS: a) Incidentally discovered thyroid cancers are more frequently
microcarcinomas; b) there appears to be no difference in terms of invasive
behavior between incidental and non-incidental thyroid cancer; c) smaller tumor
size emerges as a protective factor
Retrieval of particulate backscattering using field and satellite radiometry: Assessment of the QAA algorithm
Full text linkParticulate optical backscattering (bbp) is a crucial parameter for the study of ocean biology and oceanic carbon estimations. In this work, bbp retrieval, by the quasi-analytical algorithm (QAA), is assessed using a large in situ database of matched bbp and remote-sensing reflectance (Rrs). The QAA is also applied to satellite Rrs (ESA OC-CCI project) as well, after their validation against in situ Rrs. Additionally, the effect of Raman Scattering on QAA retrievals is studied. Results show negligible biases above random noise when QAA-derived bbp is compared to in situ bbp. In addition, Rrs from the CCI archive shows good agreement with in situ data. The QAA's functional form of spectral backscattering slope, as derived from in situ radiometry, is validated. Finally, we show the importance of correcting for Raman Scattering over clear waters prior to semi-analytical retrieval. Overall, this work demonstrates the high efficiency of QAA in the bbp detection in case of both in situ and ocean color data, but it also highlights the necessity to increase the number of observations that are severely under-sampled in respect to others environmental parameters
Urinary albumin excretion is independently associated with c-reactive protein levels in overweight and obese nondiabetic premenopausal women.
No full textOBJECTIVES:
C-reactive protein (CRP) and microalbuminuria are nowadays considered markers of chronic inflammation of the arterial wall and of endothelial dysfunction, respectively. An increase of CRP levels and of urinary albumin excretion (UAE) rate have both been reported to be independently associated with a higher risk of cardiovascular morbidity and mortality in the general population. The aim of the present study was to evaluate the possible correlation between UAE and CRP concentrations in overweight and obese premenopausal women.
DESIGN AND SETTING:
A cross-sectional study in a primary care setting. SUBJECTS, MAIN OUTCOME MEASURES: CRP levels and UAE rate were measured in 103 overweight and obese premenopausal women, aged 18-45 years. Other measurements included: central fat accumulation, as evaluated by waist circumference, insulin resistance, as calculated by homeostatic model assessment (HOMAIR); fat-free mass (FFM), as measured by bioimpedance analysis; blood pressure; and fasting plasma levels of glucose, insulin, and lipids.
RESULTS:
Urinary albumin excretion was positively correlated with body mass index (BMI) (P < 0.01), waist circumference (P < 0.001), diastolic blood pressure (P < 0.01), triglycerides (P < 0.01), HOMAIR (P < 0.05), and CRP levels (P < 0.05); and negatively associated with HDL cholesterol (P < 0.001). After multivariate analysis, diastolic blood pressure, HDL cholesterol, and CRP levels maintained their significant correlation with UAE.
CONCLUSION:
Our study shows a strong relationship between UAE and CRP concentrations, irrespective of age and other anthropometric and metabolic variables. On this basis, it can be argued that inflammation of the arterial wall, as indicated by higher CRP plasma levels, and endothelial dysfunction, as shown by higher UAE rate, might represent simultaneous phenomena in the development of atherosclerosis in overweight and obese premenopausal women
Improving the retrieval of carbon-based phytoplankton biomass from satellite ocean colour observations
Full text linkPhytoplankton is at the base of the marine food web and plays a fundamental role in the global carbon cycle. Ongoing climate change significantly impacts phytoplankton distribution in the ocean. Monitoring phytoplankton is crucial for a full understanding of changes in the marine ecosystem. To observe phytoplankton from space, chlorophyll-a concentration (Chl) has been widely used as a proxy of algal biomass, although it can be impacted by physiology. Therefore, there has been an increasing focus towards estimating phytoplankton biomass in units of carbon (Cphyto ). Here, we developed an algorithm to quantify Cphyto from space-based observations that accounts for the spatio-temporal variations of the backscattering coefficient associated with the fraction of detrital particles that do not covary with Chl. The main findings are: (i) a spatial and temporal variation of the detritus component must be accounted for in the Cphyto algorithm; (ii) the refined Cphyto algorithm performs better (relative bias of 23.7%) than any previously existing model; and (iii) our algorithm shows the lowest error in Cphyto across areas where picophytoplankton dominates (relative bias of 14%). In other areas, it is currently not possible to accurately assess the performance of the refined algorithm due to the paucity of in situ carbon data associated with nano-and micro-phytoplankton size classes
- …
