1,720,975 research outputs found
Microbes and Persistent Organic Pollutants in the Marine Environment
Full text linkMarine pollution has increased reaching the entire marine environment, from the surface to the deepest sediment, and has become more concerning in the last 70 years. Persistent organic pollutants (POPs) are a fraction of ocean waste that includes, among the others, polycyclic aromatic hydrocarbons (PAHs) and plastic polymers. These chemicals have an extremely long half-life, and (bio)accumulate and damage the marine flora and fauna, and, ultimately, human health. Some organisms have evolved enzymes to attack POPs in the environment and transform them into biomass and CO2. Several microorganisms degrade many POPs in relatively short time. A wide variety of bacteria has been isolated with different techniques, and key catabolic enzymes used to degrade the most persistent oil hydrocarbon fractions have been identified. For plastic waste, there is less evidence of microbial degradation, but a few recent studies are revealing that a biodegradation potential exists for some of the most recalcitrant plastic polymers as well. The scientific community is focusing on microorganisms and their enzymes for POP uptake and removal from the environment, while searching novel biopolymers (also from microbiological origin) to substitute oil-derived plastics
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
The risk of recurrent cardiovascular events in patients with increased plasma homocysteine levels is reduced by short but not long-term therapy with folate and B vitamins.
No full textHyperhomocysteinemia is considered an independent risk factor for atherosclerosis, atherothrombosis and Venous ThromboEmbolism (VTE) [1], [2] and [3]. Normal total plasma homocysteine concentrations range from 5 to 15 μmol/L in the fasting state. Hyperhomocysteinemia is classified as moderate (homocysteine concentration, 15 to 30 μmol/L), intermediate (> 30 to 100 μmol/L), and severe (> 100 μmol/L) on the basis of concentrations measured during fasting. Although severe hyperhomocysteinemia is rare, mild hyperhomocysteinemia occurs in approximately 5% to 7% of the general population. In this case, patients are typically asymptomatic until the third or fourth decade of life when premature Coronary Artery Disease (CAD) develops, as well as recurrent arterial and venous thrombosis [1] and [2]. Vitamin supplementation (Folic Acid and B Vitamins) usually decreases or even normalizes plasma homocysteine concentrations in most cases [1]; however, the advantages of such approach is not always evident [3]. Recently, the results of the Norwegian Vitamin (NORVIT) trial and the Heart Outcomes Prevention Evaluation (HOPE) 2 trial have shown that, after a median follow-up of 40 months, despite a 27% lowering of the mean total homocysteine concentration from the baseline value among patients treated with folic acid and vitamin B12, there was no significant effect on the risk of the composite primary end points (recurrent myocardial infarction, stroke, or sudden death CAD) [4] and [5]....
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
Non-immune hydrops fetalis: Two case reports
Full text linkBACKGROUND Fetal hydrops is a serious condition difficult to manage, often with a poor prognosis, and it is characterized by the collection of fluid in the extravascular compartments. Before 1968, the most frequent cause was the maternal-fetal Rh incompatibility. Today, 90% of the cases are non-immune hydrops fetalis. Multiple fetal anatomic and functional disorders can cause non-immune hydrops fetalis and the pathogenesis is incompletely understood. Etiology varies from viral infections to heart disease, chromosomal abnormalities, hematological and autoimmune causes. CASE SUMMARY A 38-year-old pregnant woman has neck lymphoadenomegaly, fever, cough, tonsillar plaques at 14 wk of amenorrhea and a rash with widespread itching. At 27.5 wk a fetal ultrasound shows signs of severe anemia and hydrops. Cordo-centesis is performed with confirmation of severe fetal anemia and subsequent fetal transfusion. The karyotype is 46, XX, array-comparative genome hybridization (CGH) negative, and infectious tests are not conclusive. In the following days there is a progressive improvement of the indirect signs of fetal anemia. At 33.6 wk, for relapse of severe fetal anemia, further fetal transfusions are necessary and an urgent cesarean section is performed. On the day 12 of life, for the detection of anemia, the newborn is subjected to transfusion of concentrated red blood cells and begins treatment with erythropoietin. Later there is a normalization of blood chemistry values and the baby does not need new transfusions. A 29-year-old pregnant woman, with Sjogren's syndrome and positive Anti-Ro/SSA antibodies, is subjected to serial fetal ecocardio for branch block. At 26.5 wk there is a finding of fetal ascites. Infectious disease tests on amniotic fluid are negative as well as quantitative fluorescent polymerase chain reaction, Array CGH. At cordocentesis Hb is 1.3 mmol/L, consequently fetal transfusion is performed. Also in this case, due to continuous episodes of relapse of fetal anemia with consequent transfusions, at 29.4 wk a cesarean section is performed. On day 9 of life, a treatment with erythropoietin is started in the newborn, but the baby needs three blood transfusions. The search for autoantibodies in the baby found SS-A Ro60 positive, SSA-Ro52 positive and SS-B negative. The hemoglobin values normalized after the disappearance of maternal autoantibodies. CONCLUSION An attempt to determine the etiology of hydrops should be made at the time of diagnosis because the goal is to treat underlying cause, whenever possible. Even if the infectious examinations are not conclusive, but the pregnancy history is strongly suggestive of infection as in the first case, the infectious etiology must not be excluded. In the second case, instead, transplacental passage of maternal autoantibodies caused hydrops fetalis and severe anemia. Finally, obstetric management must be aimed at fetal support up to an optimal timing for delivery by evaluating risks and benefits to increase the chances of survival without sequelae
Epinephelus sicanus (Doderlein, 1882) (Perciformes: Serranidae: Epinephelinae), a valid species of grouper from the Mediterranean Sea
No full textThe aim of the present statement is to prove that the name Cerna sicana Doderlein, 1882 (presently as Epinephelus sicanus [Doderlein, 1882]) should be considered a valid species unless it is demonstrated that it is a synonym of another valid species. At present no research has demonstrated that Epinephelus sicanus is a synonym of another species of Epinephelus or related genera, only hypotheses have been formulated. Epinephelus sicanus was overlooked by most fish catalogues or reported as uncertain synonym of other species. It is here proposed to include this taxon in all fish catalogues as valid species, and it is recommended to perform additional taxonomical or molecular analyses
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