1,721,102 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
EFFECT OF 14 DAYS AT 15 METRES DEPTH ON HORMONAL STRESS PARAMETERS. Abyss Project 2007 - The House on the sea bottom
Full text linkINTRODUCTION : Recreational scuba divers are exposed to environmental stresses including increased environmental pressure, raising of oxygen partial pressure, increased resistance to movement, added weight of diving equipment and cold stress (1). During the scuba dive, increased ambient pressure generates an increase in and PO2. nitrogen partial pressure. A decrease in cardiac output (CO) related to the simultaneous decrease of the heart rate (HR) and the stroke volume (SV) is found at high PO2. The aim of this study was to measure hormonal stress parameters in six professional trainers scuba divers to test the hypotheses that hormones release may be influenced by prolonged water submersion. Six scuba divers, three males and three females, participated in the study while trying to achieve the Guinness 14 days scuba dive in september 2007. They spent 14 days at the depth of 15 metres in Ponza Island sea (Italy) to establish a new record. METHODS: Four different blood samples were collected to evaluate hormonal stress parameters (ACTH, cortisol, prolactin, quantified by routine clinical laboratory methods, Modular E, Roche, Basel, Switzerland). Serum was immediately separated by centrifugation at 1500xg for 15 min. and stored at -20°C until analysed. The first blood samples was collected in Rome 5 days before immersion and the next three collected every five days, during the immersion, in the underwater bell and carried out water in waterproof bag. Data have been compared by paired t test, differences were considered statistically significant at P<0.05.RESULTS: Our results show a significant decrease in plasma hormone levels in the three underwater drawing respect the basal. The results obtained during the staying to 15 metres depth show a significant raise in the second underwater drawing in cortisol and ACTH. The prolactin levels show the same variations of cortisol and ACTH, but less remarkable. All values of parameters measured fall in the normal range.CONCLUSION: According to our data, we may conclude that a prolonged water immersion does not seem to be a stressor condition. Indeed the plasma hormone concentrations significantly decrease after depth, remaining lower than basal. All the hormones tested show an increase after a week in the water immersion, these might suggest a state of elevated physical and mental activation and vigilance. It has even been reported that scuba diving decreases salivary cortisol levels in recreational scuba divers (2). During the diving period the subjects didn’t show anxiety and depression, or panic symptoms; on the contrary they seem be happy to live underwater.
Depending on non existence of hormonal disorders we may hypothesized that long duration water submersion might has not influenced the hypothalamic-pituitary axis in our divers
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
OXIDATIVE STRESS ASSESSMENT IN PROFESSIONAL SOCCER PLAYERS: EVALUATION DURING A SPORT SEASON
Full text linkBACKGROUND: There is a possibility that oxidative damage caused by intensive training periods might compromise the healthy status of the players as well as exercise performance [1].
The following up of d-ROMs (Reactive Oxygen Metabolites- derived compounds) and BAP (Biological Antioxidant Potential) during the professional soccer training process could be one of the indicators of the training effects.
OBJECTIVES: The aim of this study is to evaluate the changes in oxidative balance due to an increased production of oxidant species and/or a decreased efficacy of antioxidant system, can lead to oxidative stress an emerging health risk factor involved in the aging and in many diseases, including inflammatory, infectious and degenerative disorders.
METHODS: We included 35 professional soccer players from two soccer club of our National Soccer League in this study. 10 ml blood samples were obtained from the antecubital vein early in the morning and after centrifugation (800gx5min.), the supernatants were stored at -20°C until the assays. Plasma ROMs (mainly hydroperoxides) and biological antioxidant potential were measured respectively by d-ROM test and BAP test, (Diacron International s.r.l., Grosseto, Italy). Data have been compared by paired t test, differences were considered statistically significant at P<0.05. All sport medical examinations were conducted tree times: the first before the preparation phase, the second and the third during the competition phase.
RESULTS: There were significant differences in plasma concentration of reactive oxygen metabolites (ROMs) and biological antioxidant potential (BAP) in response to the physical exercise showing the adaptation of antioxidant response in order to avoid oxidative damage (2).
CONCLUSION: The results obtained show a different response to training during the season in a soccer club enrolled in this study, emphasizing that different training may influence changes in oxidative balance
Evaluation of two automatic systems for measurement of the erythrocyte sedimentation rate
Full text linkOur aim was to compare two different automated devices for the measurement of the length of erythrocyte sedimentation rate (LSRB) in order to decrease the amount of blood sample collected. We compared VES-MATIC 60 (DIESSE s.p.a.,Grosseto, Italy) with VES-CUBE 200 (DIESSE s.p.a.,Grosseto, Italy), that requires K2-EDTA and sodium-citrate blood samples, respectively. A total of 160 whole blood samples from patients of the Laboratory Medicine of University Hospital “Tor Vergata” Rome were included in this study; LSRB was determined following ICSH recommendations. Linear regression analysis was used for accuracy study; Reproducibility was assessed using an internal quality control for at least one month (mean = 6.93, SD = 0.775 CV=10.5).
Our data showed statistically significant correlation between the two different systems, when the data of VES-CUBE 200 were adjusted to 18°C by Manley’s normogramm. Moreover, both systems presented a good reproducibility and similar CV value.
In conclusion, both systems can be used for LSRB determination with the same range of reference; in addition, our previous study showed that LSRB values on plasma-citrate or on K2-EDTA were the same on VES-MATIC 60, therefore the automatic system for LSRB measurement, VES-CUBE 200, shows important advantages on one hand it decreases the amount of whole blood collected being the sample undiluted, on the other hand the test can be performed on the same tube collected for hemochrome analysis, using K2-EDTA as anticoagulant.
1)Caswell M, Stuart J. Assessment of Diesse Ves-matic automated system for measuring erythrocyte sedimentation rate. J Clin Pathol 1992 Feb;45(2):18
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
Length of sedimentation reaction in blood: a comparison between plasma citrate and K2-EDTA blood samples.
Full text linkIntroduction
The erythrocyte sedimentation rate (ESR), now more appropriately referred to as "length of sedimentation reaction in blood (LSRB)", remains the most widely used laboratory test for monitoring the course of infections, inflammatory diseases and some types of cancer. In addition, it is simple and low-cost. The most commonly used procedures for LSRB determination requires plasma-citrate blood samples, following ICSH (International Committee for Standardization in Haematology) recommendations. It is no unlikely that LSRB blood samples are insufficient, especially in children and in haemathological patients. In order to resolve this inconvenient, we compared LSRB measurement in plasma citrate and in K2-EDTA blood samples.
Methods
We performed our study on 300 whole blood samples from patients of Medicine Laboratory of University Hospital “Tor Vergata” Rome, using an automated procedure (VES-MATIC 60 DIESSE s.p.a.,Grosseto, Italy)
Plasma citrate blood samples were analyzed and used as control, whereas K2-EDTA blood samples were transferred in tubes containing sodium-citrate and then analyzed.
Statistical correlation was performed using Pearson’s correlation.
Results and Discussion
Results of linear regression are shown in Figure. There was a close correlation in LSRB measurements between plasma citrate and in K2-EDTA The regression line had a slope of 0.995 and an intercept of -0.42. The LSRB is a non specific laboratory test widely used in clinical practice. However, this test is used conventionally to detect acute or chronic systemic inflammation in a number of diverse conditions and to monitor the response to therapy. Our results demonstrate that there are not differences between citrate and K2-EDTA plasma therefore LSRB can be eventually measured from the tube collected for hemochrome analysis and so resolve the inconvenient of insufficient samples; besides the use of samples anticoagulated with K2 EDTA can widely reduce the workload in clinical laboratories
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