1,721,003 research outputs found
High-Risk Pregnancy Is Associated With Increased Alpha-Fetoprotein Concentrations in the Amniotic Fluid and Foal Plasma
Full text linkThis study aimed to determine alpha-fetoprotein (AFP) concentrations in amniotic fluid, plasma of mares and respective foals: carrying normal pregnancies and delivering healthy foals (n = 20; Group 1); carrying apparently normal pregnancies and delivering sick foals (n = 15; Group 2); carrying high-risk pregnancies and delivering sick foals (n = 14; Group 3). High-risk pregnancy was defined by a history of premature udder development/lactation or increased of the combined thickness of the uterus and placenta, or vulvar discharge and/or mares' systemic illness. Sick foals were affected by neonatal encephalopathy, sepsis, prematurity/dysmaturity, or hypoxic-ischemic encephalopathy. Based on histological examination of the chorioallantois, AFP trend was analyzed in pregnancies with pathologic (PFM) and normal fetal membranes (NFM). Concentrations of AFP were measured using a commercially available immunoassay previously validated for horses. Mares' plasma AFP did not change during the last 15-20 days of pregnancy in the three groups, and there was no difference among them. Amniotic fluid AFP was higher in Group 3 (P = .014). Foals' plasma AFP concentration was higher from birth to 72hours in foals of Group 2 and 3 than in healthy ones, and foals of Group 3 had the highest value. The strong association (r = 0.84; P < .0001) between AFP in amniotic fluid and foals' plasma at birth is likely due to the presence of AFP in fetal urine. AFP was higher in pregnancy with PFM than with NFM in mare's plasma at admission (P = .031), amniotic fluid (P = .004), foal's plasma at birth (P = .002), at 24 (P = .005) and at 72 hours of life (P = .004). AFP is higher in pregnancy with histopathological lesions of the chorioallantois providing the evidence of the differences between pregnancy with a normal placental barrier and the more compromised ones. The increased AFP concentration in the amniotic fluid and plasma of high-risk foals suggests upregulation
Characterization of pregnancy-associated glycoproteins and progesterone as a predictor of twins and conceptus loss in high-risk pregnancy Holstein cows
Full text linkPregnancy loss is a multifactorial condition that compromises reproductive performance in dairy operations. Despite the high oocyte fertilization rate in dairy cows, only 28 % of those maintain a pregnancy to term. Pregnancy loss is estimated to cost U$600.00 per case. Identification of cows losing the pregnancy as early as possible can be helpful in providing timely opportunities for rebreeding, thus potentially minimizing economic losses. Traditionally, early pregnancy diagnosis is performed via ultrasonography, starting at 30 days, which provides information regarding embryo viability, uterine health, and ovarian structures. In addition, this technique allows the diagnosis of twin pregnancy that is three times more likely to be lost than a singleton. Despite its benefits ultrasonography requires well-trained personnel and incurs additional costs involving equipment purchase and maintenance. The use of biomarkers has been studied throughout the years, based on a demand for an easier, less costly, and more accurate test. Pregnancy-associated glycoproteins (PAG) is the most common biomarker marker to assess pregnancy status in cows. Produced and secreted on the maternal circulation by binucleate giant cells. Measurement of PAG in the blood has high sensitivity when performed between 25 32 days of gestation, however, the specificity can be as low as 83%. One of the major components that affect test accuracy is pregnancy loss. It has been reported that cows experiencing early pregnancy loss, present lower plasma concentrations of PAG. Another indirect biomarker to detect pregnancy in cows is progesterone. Cows experiencing pregnancy loss showed lower concentrations of this hormone, in comparison to cows keeping the pregnancy. The development of a threshold for PAG and progesterone that can predict pregnancy loss may aid in management decisions to provide earlier rebreeding opportunities. It was hypothesized that the plasma concentration of PAG and progesterone is reduced and can predict pregnancy loss in cows experiencing a high-risk pregnancy. Additionally, it was hypothesized that the concentration of PAG and progesterone are increased and can predict twins. High-risk pregnancy (HR) were characterized using transrectal ultrasonography 37 days post-AI based on the following criteria: small embryo size (SE, embryo < 15 mm, n=10), slow heartbeat (SH, <60 beats per minute, n = 11), extra amniotic membrane (EM, additional amniotic membrane, n=3). A cohort of twins (TW, n = 41) diagnosed at day 37 post-AI was also enrolled. Twins were also subgroups in unilateral (UT, n=17) and bilateral (BT, n=24). Each HR and TW cow was paired with the same parity cow carrying a normal singleton at d 37 post-AI (CON, n = 65). Blood samples were collected to measure PAG and progesterone at 37, 44, and 51 post-AI. Statistical analysis was performed using ANOVA, logistic regression and receiver operation characteristics (ROC) with JMP. Pregnancy loss at day 51 post-AI was greater (P < 0.01) in HR than CON and TW (CON=1.5%; HR=87.5%; TW=12.2%). Concentration of PAG at day 37 post-AI did not differ (P = 0.75) among groups (CON = 5.3 ± 0.7; HR = 4.8 ± 1.2; TW = 4.0 ± 0.9 ng/ml). The subgroup SE showed a statistical difference regarding the concentration of PAG at day 51 post-AI (P < 0.05), EM showed a tendency (P < 0.10) whereas SH, UT and BT did not when compared to CON. Concentration of progesterone at day 37 post-AI was greater in TW than HR and CON, and lower (P < 0.01) in HR than CON cows (CON = 7.0 ± 0.3; HR = 5.9 ± 0.4; TW = 8.4 ± 0.3 ng/ml). Regression and ROC analysis for PAG at day 37 post-AI did not find a threshold to predict pregnancy loss (P = 0.24) or twins (P = 0.30). Regression and ROC analysis for progesterone at day 37 post-AI found that a threshold of 6.5 ng/ml predicted (P < 0.01) pregnancy loss with an area under the curve (AUC) of 0.65, and threshold of 7.2 ng/ml predicted (P < 0.01) twins with AUC of 0.70. In summary, pregnancy loss and twins were predicted with only moderate accuracy by progesterone concentration at day 37 post-AI and the variability in PAG concentrations at day 37 post-AI was insufficient to generate a threshold to predict pregnancy loss and twins in Holstein lactating cows.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2020-10-02 without embargo termsThe student, Phillip Peixoto, accepted the attached license on 2020-05-14 at 10:09.The student, Phillip Peixoto, submitted this Thesis for approval on 2020-05-14 at 10:25.This Thesis was approved for publication on 2020-05-15 at 15:02.DSpace SAF Submission Ingestion Package generated from Vireo submission #15391 on 2020-10-02 at 15:09:53Made available in DSpace on 2020-10-07T20:59:19Z (GMT). No. of bitstreams: 3
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Previous issue date: 2020-05-1
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
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