1,720,953 research outputs found
The risk and severity of preeclampsia secondary to iodine deficiency and iodine deficiency-mediated subclinical hypothyroidism: mechanisms and early cardiovascular consequences
Full text linkBackground Iodine deficiency affects about 2 billion people globally and is the leading cause of Subclinical (SCH) and overt (OH) hypothyroidism that are some of the risk factors of preeclampsia. Iodine deficiency in pregnancy, which can be corrected by supplementation, has been suggested in the past three decades as a risk factor for preeclampsia. It is uncertain if this is mainly because of elevated thyroid-stimulating hormone (TSH) in women with iodine deficiency complicated by hypothyroidism. Alternatively, it may be because of reduced serum antioxidant capacity and other pathways that are associated with the more prevalent inadequate iodine intake in pregnancy, or both. Aims The current thesis had three major objectives: 1) To determine the burden of iodine deficiency in pregnancy in Africa; 2) To find out if there is an association between iodine deficiency in pregnancy, subclinical hypothyroidism, endothelial dysfunction and preeclampsia; 3) To find out possible mechanisms through which iodine deficiency in pregnancy may predispose to preeclampsia, eclampsia, endothelial dysfunction and early cardiovascular pathological changes. Methods In the first part of this thesis, two systematic reviews are presented. The first was carried out in order to estimate the burden of iodine deficiency in pregnancy in Africa. This was complemented with a regression analysis using the more readily available school-age children (SAC) median urinary iodine concentration (UIC) and the limited pregnancy median UIC data to estimate the level of iodine nutrition in pregnancy in all the African countries. The second systematic review was carried out to find out the relationship between inadequate iodine intake in pregnancy and preeclampsia. In the second part of this thesis, we present results of case-control studies in which women with preeclampsia, severe preeclampsia, eclampsia and normotensive pregnant controls were enrolled at Nelson Mandela Academic Hospital (NMAH) and Mthatha Regional Hospital (MRH) in Eastern Cape South Africa. Their iodine nutrition status, thyroid function, endothelial dysfunction and arterial stiffness were compared by assaying the urinary iodine concentration (UIC), thyroglobulin (Tg), thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), nitric oxide (NO), oxidised low-density lipoprotein (oxLDL), pulse wave velocity (PWV) and aortic augmentation index (AI). In the third part of the thesis, two studies aimed at exploring mechanisms through which iodine and other micronutrient deficiencies together with environmental factors predispose to preeclampsia and eclampsia are presented. The first is a study using Factor Analysis to find out how various nutritional and inflammatory markers interact in different pathways to predispose to preeclampsia using data collected at Lomo Medical Centre, Kinshasa Province, Democratic Republic of Congo. The second is a case-control study in which we compared the thyroid function status, urinary iodine and serum potassium of women with eclampsia, severe preeclampsia and normotensive pregnant controls to find out if iodine deficiency, the resultant thyroid dysfunction and serum potassium levels were associated with the risk of eclampsia. Results Prevalence of iodine deficiency in pregnancy in Africa: results from systematic reviews and meta-analyses and pregnancy median UIC estimated from SAC median UIC Pregnancy iodine nutrition status data was available for 23/54 African countries. Between 2005 and 2020 a few African countries had sufficient (pregnancy median urinary iodine concentration [pMUIC] 150 - 250 μg/L), most had mildly inadequate (pMUIC 100 - 149 μg/L), and some moderate-to-severe inadequate iodine nutrition in pregnancy (pMUIC 50). There was a non-significant risk of preeclampsia for women with UIC < 0.001) and the Pulse Wave Velocity 5.1, 5.7 and 6.3 m/s respectively for Eastern Cape normotensive, preeclampsia and severe preeclampsia women (p< 0.05). In linear regressions, TSH, age and hypertensive disease were independent predictors of elevated PWV which is associated with endothelial dysfunction and future cardiovascular disease. Possible mechanisms in the pathophysiology of preeclampsia associated with iodine deficiency, resultant thyroid dysfunction and other nutritional or inflammatory factors Using data of normotensive and preeclamptic women from Kinshasa Province, Democratic Republic of Congo, we have characterised four main pathophysiological pathways through which low iodine intake in pregnancy may predispose to preeclampsia. These are the interactions between selenium/iodine deficiency and elevated serum TSH, leading to endothelial dysfunction; serum ferritin, gamma-glutamyl transferase (GGT), C-reactive protein (CRP) and low urinary iodine excretion precipitating inflammatory oxidative stress. The others are elevated serum high sense-CRP (hs-CRP) and Rheumatoid factor subclinical inflammation and immune cell activation and high T3/T4 ratio acute TSH stimulation of thyroid with low thyroid iodine stores that may lead to excessive superoxide and hydroxyl production further exacerbating oxidative stress and endothelial dysfunction. Iodine deficiency, thyroid dysfunction in the pathophysiology of eclamptic fits Eclamptic women in the Eastern Cape (South Africa) had significantly lower urinary iodine concentration (UIC), free triiodothyronine (FT3), median serum potassium (K), but higher serum thyroglobulin (Tg) than women with severe preeclampsia and normotensive pregnant controls. The median values respectively for participants with eclampsia, severe preeclampsia and normotensive controls were UIC 69.5, 95.7, and 169.5 µg/L; FT3 3.8, 4.4 and 4.7 pmol/L; K 3.7, 4.2, 4.3 mmol/L; and Tg 39.0, 22.4, 19.5 µg/L. Low serum T3 and T4 levels coupled with a preferential transfer of T4 across the blood-brain barrier alter the physiological T3/T4 ratio in the CNS attenuating the inhibitory effects of GABA while the excitatory function of glutamate remains intact. Low serum potassium further attenuates GABAB receptor mediated tonic extra-synaptic inhibition resulting in net motor neurone stimulation and increased predisposition to the involuntary tonic-clonic convulsions observed in eclampsia. Conclusion There is still a high prevalence of inadequate iodine intake in pregnancy in Africa estimated to affect 45% of the African nations 25 years after commencement of iodine fortification of salt and other foodstuffs. While the complication of goitre and cretinism may have reduced, pregnant women in Africa may still be prone to high risk of preeclampsia, eclampsia, future cardiovascular disease and various degrees of reduced psychomotor development of the foetus depending on the severity and duration of insufficient iodine intake in pregnancy. Alternative measures need to be considered to mitigate the persistently high prevalence of iodine deficiency in pregnancy in Africa and other areas around the globe despite national salt iodization programs and other iodine fortification efforts that have been implemented for several decades. This will help reduce the risk of preeclampsia, eclampsia and related complications
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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