1,721,006 research outputs found
The effect of experimental unilateral cryptorchidism on the contralateral exocrine testicular function in arabbit model
No full textThe effect of experimental unilateral cryptorchidism on the contralateral exocrine testicular function in a rabbit model. Dimitriadis Fotios MD FEBU It is well known that subfertility is frequently observed in cases of cryptorchidism. The degenerative changes which occur in the cryptorchid testis have been noted by many investigators and are believed to be a cause of male infertility in bilateral cryptorchidism. However, the matter of fertility in patients with unilateral cryptorchidism continues to be argued, although several studies have shown a decrease in fertility in patients with unilateral undescended testis. The most debated issues include: a) the existence or not of the decreased fertility in these patients as a result of the bilateral effect of the unilateral undescended testis, b) the role of the undescended testis in the contralateral testicular damage or the presents of other reasons such as underlying congenital defect, c) the rate of the germ cells and in particular spermatogenic sperm cells (that is spermatogonia) which survive the cryptorchid state, d) the extend of the contralateral testicular damage, and e) the pathogenesis of the decreased fertility in these patients. In the present study we used rabbit model of intra-abdominal unilateral cryptorchidism to compare the fertility, hormonal profile, and histological changes of both the undescended and descended testes by means of light microscopy. Unilateral cryptorchidism was induced in twenty male 5 month old New Zealand white rabbits (Group I) by returning the right testis, together with the ipsilateral epididymis and spermatic cord, to the abdominal cavity through an inguinal incision. The inguinal ring was closed with a suture. Another twenty male age-matched New Zealand white rabbits (Group II) underwent sham operation and served as control group. All operations were performed by an experienced surgeon and anesthesia was induced by intramuscular administration of ketamine 15mg/kg body weight as anesthetic followed by subcutaneous administration of xylazine 15mg/kg body weight as pain killer and muscle relaxant as well as subcutaneous administration of heparin 120 U/Kg body weight as anticoagulant. One hundred and nineteen days after the experiment, the fertility of both groups was assessed by mating 10 rabbits from each group selected randomly with mature females of proven fertility (two successful parturitions in the past). The next day (120 days after the experiment) peripheral blood sample was aspirated from an ear vein for the assessment of basal testosterone level. After one day (121 days after the experiment) hCG (5000U/animal) was administered intramuscularly in all male animals and three hours later peripheral blood sample was aspirated to assess the response of testosterone. The next day (122 days after the experiment) all the male animals were killed and all the testes were extracted, weighed, and processed for histological evaluation. The last day of the experiment (144th day) all the female animals were killed and the number of embryos inside the uterus was registered. Bilateral testicular weight was significantly smaller in group I than in group II. In addition mean seminiferous tubule diameter, mean seminiferous tubule area, mean number of round spermatids per seminiferous tubule, and mean number of primary spermatocytes/seminiferous tubule was significantly smaller bilaterally in group I than in group II. Furthermore basal testosterone levels and testosterone responses to hCG stimulation were significantly smaller in group I than in group II. Moreover, the proportion of fertile rabbits to the total number of rabbits was significantly smaller in group I than in group II. These results suggest that intra-abdominal cryptorchid testes are significantly impaired, and that such impairment might be caused by exposure of the testis to a higher temperature. The more severely impaired undescended testes may thus induce the degeneration of the exocrine function of the contralateral scrotal testis and thereby cause subfertility in the intra-abdominal unilateral cryptorchid rabbit model. Moreover, the results of the current study provide some evidence of the detrimental effects of unilateral cryptorchidism on testicular endocrine function of the contralateral testis.Ο σκοπός της παρούσας πειραματικής διατριβής ήταν η μελέτη της εξωκρινούς μοίρας του όρχη σε κουνέλια με κρυψορχία του δεξιού όρχη. Χρησιμοποιήθηκαν σαράντα αρσενικά κουνέλια (New Zealand White Rabbits) ηλικίας πέντε μηνών τα οποία χωρίστηκαν σε δύο ομάδες των είκοσι ζώων. Τα κουνέλια της ομάδας Ι υποβλήθηκαν σε επέμβαση πρόκλησης δεξιάς κρυψορχίας με επιμήκη τομή στο ύψος του έσω δακτυλίου του δεξιού βουβωνικού καναλιού. Τα κουνέλια της ομάδας ΙΙ υποβλήθηκαν σε εικονική επέμβαση κρυψορχίας και χρησιμοποιηθήκαν ως ομάδα ελέγχου. Επίσης χρησιμοποιήθηκαν είκοσι ενήλικα θηλυκά κουνέλια τις ιδίας φυλής για τη δοκιμασία γονιμότητας. Την 119η ημέρα της πειραματικής φάσης έγινε η δοκιμασία γονιμότητας κατά την οποία δέκα αρσενικά κουνέλια από κάθε ομάδα επιλεγμένα με τυχαίο τρόπο τοποθετήθηκαν το κάθε ένα ξεχωριστά μαζί με ένα θηλυκό στον ίδιο κλωβό για 24 ώρες, με σκοπό την επίτευξη της γονιμοποίησης. Την 120η ημέρα της πειραματικής φάσης έγινε λήψη δειγμάτων φλεβικού αίματος των δύο ομάδων και μετρήθηκαν τα περιφερικά επίπεδα της τεστοστερόνης. Την 121η ημέρα της πειραματικής φάσης πραγματοποιήθηκε δοκιμασία πρόκλησης τεστοστερόνης με ενδομυϊκή ένεση 5000 U ανθρώπινης χοριονικής γοναδοτροπίνης (hCG) και μετά από τρεις (3) ώρες επανεκτιμήθηκαν τα περιφερικά επίπεδα της τεστοστερόνης ορού του φλεβικού αίματος. Την 122η ημέρα της πειραματικής φάσης τα πειραματόζωα θυσιάστηκαν προκειμένου να αφαιρεθούν οι όρχεις. Το κάθε όργανο, παρασκευάσθηκε προσεκτικά με τη βοήθεια μικροσκοπίου και ζυγίστηκε σε ζυγό ακριβείας. Πραγματοποιήθηκε κατάλληλη έγκληση δείγματος ιστών από το κάθε όργανο προκειμένου να μελετηθούν τυχών αλλοιώσεις του στο οπτικό μικροσκόπιο. Την 144η ημέρα του πειραματισμού τα θηλυκά πειραματόζωα θυσιάστηκαν προκειμένου να ελεγχθεί η μήτρα ως προς την ύπαρξη ή μη εμβρύων. Οι δεξιοί και αριστεροί όρχεις των πειραματόζωων της ομάδας Ι είχαν στατιστικά σημαντικά μικρότερο βάρος από τους αντίστοιχους δεξιούς και αριστερούς όρχεις της ομάδας ελέγχου. Επιπλέον, η μέση διάμετρος των σπερματικών σωληναρίων, το μέσο εμβαδό των σπερματικών σωληναρίων, ο μέσος αριθμός των στρογγυλών σπερματίδων ανά σπερματικό σωληνάριο και ο μέσος αριθμός πρωτογενών σπερμοκυττάρων ανά σπερματικό σωληνάριο στην ομάδα Ι ήταν στατιστικά σημαντικά χαμηλότεροι από ότι στην ομάδα ΙΙ. Επίσης, τα βασικά επίπεδα τεστοστερόνης και η έκκριση τεστοστερόνης μετά από πρόκληση με hCG ήταν στατιστικά σημαντικά χαμηλότερες στα πειραματόζωα της ομάδας Ι από ότι στα πειραματόζωα της ομάδας ελέγχου. Τέλος, τα πειραματόζωα της ομάδας Ι είχαν στατιστικά σημαντικά χαμηλότερη γονιμοποιητική ικανότητα από ότι τα πειραματόζωα της ομάδας ΙΙ. Συμπερασματικά, η χειρουργική πρόκληση μονόπλευρης κρυψορχίας σε ενήλικα κουνέλια είχε σαν αποτέλεσμα την πρόκληση έντονων αλλοιώσεων στον ενδοκοιλιακό όρχη αλλά και την πρόκληση πιο ήπιων αλλά ωστόσο στατιστικά σημαντικών αλλοιώσεων στον ετερόπλευρο οσχεϊκό όρχη σε σύγκριση με τα ζώα της ομάδας ελέγχου. Εκτός από τις ούτως ή άλλως καλά τεκμηριωμένες αλλοιώσεις που εντοπίστηκαν στον ενδοκοιλιακό όρχη στην παρούσα εργασία καταφέραμε να αποδείξουμε την ύπαρξη σημαντικών αλλοιώσεων και στον ετερόπλευρο οσχεϊκό όρχη. Το γεγονός αυτό εξηγεί την μειωμένη γονιμοποιητική ικανότητα των μονόπλευρα κρυψορχικών κουνελιών σε σχέση με την ομάδα ελέγχου
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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