1,720,960 research outputs found
Exposure to E2 and EE2 environmental concentrations affect different components of the Brain-Pituitary-Gonadal axis in pejerrey fish (Odontesthes bonariensis)
Get PDFThe present study focuses on the effects of E2 and EE2 environmental concentrations on different components of the reproductive axis of pejerrey (Odontesthes bonariensis), a native fish species from Pampas lakes of Argentina. The results obtained demonstrated that E2 and EE2 separate or mixed, could disrupt key pathways of the pejerrey Brain-Pituitary-Gonadal axis. First, it was observed that at the brain level, gnrh-III and cyp19a1b mRNA expression increased significantly in the exposed fish. Secondly, in the pituitary fshb and lhb mRNA expression levels, the study did not show any differences between treated and control groups. Thirdly, fshr and lhcgr transcript levels showed a significant decrease at testicular level. Nevertheless, testosterone plasmatic levels remained unchanged in exposed fish. In addition, in a histological analysis, it was possible to find pyknotic nuclei in estrogen only on treated fish testis linked to a reduction in the GSI index and a decrease in the length of spermatogenic lobules. All these findings highlighted the fact that environmental concentrations of E2, EE2 and their mixture disrupted the endocrine-reproductive axis of pejerrey, being the testis the main direct target.Fil: Garriz, Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: del Fresno, Pamela Sabrina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Miranda, Leandro Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin
Influence of pejerrey Odontesthes bonariensis(Valenciennes, 1835) broodstock age on gamete quality, reproductive performance and plasma sex steroid levels during the spawning season
Get PDFThis study evaluated the effect of pejerrey Odontesthes bonariensis (Valenciennes, 1835) broodstock age on gamete and spawning quality and its relationship with sex steroid plasma levels. Sperm was analysed using a computer-assisted sperm analysis (CASA) developed for pejerrey. Semen samples were taken from all fish from mid age groups (5- and 7-year fish), but it was not possible to obtain stripped semen samples from all fish of younger (3-year) or older (10-year) groups. The highest relative sperm weight and sperm concentration were recorded in 5- and 7-year groups respectively, while viability was not different between age groups. It was not possible to identify an effect of age on sperm quality by CASA. Non-viable spawned eggs were obtained in the 3-year group and, the relative fecundity and the relative number of fertilized eggs decreased with age in other groups. Fertilization and hatching rates showed the highest values in the 10-year group. However, the estimated number of hatched larvae was similar in 5-, 7- and 10-year fish. A clear effect of age on 11 ketotestosterone (11-KT) and estradiol (E2) levels was identified, with the highest values in the 5- and 7-year groups. These results might be related to the onset of puberty in the 3-year group and ageing in the 10-year group. Considering that the estimated number of larvae obtained was similar among age groups, the results of this study suggest that broodstock maintenance cost could be reduced by using mid-age fish rather than older fish in pejerrey hatcheries.Fil: Chalde, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Garriz, Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Sanches, Eduardo A.. Universidade de Sao Paulo; BrasilFil: Miranda, Leandro Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; Argentin
Influence of pejerrey Odontesthes bonariensis (Valenciennes, 1835) broodstock age on gamete quality, reproductive performance and plasma sex steroid levels during the spawning season
Get PDFThis study evaluated the effect of pejerrey Odontesthes bonariensis (Valenciennes, 1835) broodstock age on gamete and spawning quality and its relationship with sex steroid plasma levels. Sperm was analysed using a computer-assisted sperm analysis CASA) developed for pejerrey. Semen samples were taken from all fish from mid age groups (5- and 7-year fish), but it was not possible to obtain stripped semen samples from all fish of younger (3-year) or older (10-year) groups. The highest relative sperm weight and sperm concentration were recorded in 5- and 7-year groups respectively, while viability was not different between age groups. It was not possible to identify an effect of age on sperm quality by CASA. Nonviable spawned eggs were obtained in the 3-year group and, the relative fecundity and the relative number of fertilized eggs decreased with age in other groups. Fertilization and hatching rates showed the highest values in the 10-year group. However, the estimated number of hatched larvae was similar in 5-, 7- and 10-year fish. A clear effect of age on 11 ketotestosterone (11-KT) and estradiol (E2) levels was identified, with the highest values in the 5- and 7-year groups. These results might be related to the onset of puberty in the 3- year group and ageing in the 10-year group. Considering that the estimated number of larvae obtained was similar among age groups, the results of this study suggest that broodstock maintenancecost could be reduced by using mid-age fish rather than older fish in pejerrey hatcheries.Fil: Chalde, Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); ArgentinaFil: Garriz, Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); ArgentinaFil: Sanches, Eduardo A.. Universidade de Sao Paulo; BrasilFil: Miranda, Leandro Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús. Instituto de Investigaciones Biotecnológicas (sede Chascomús); Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Effects of estradiol and ethinylestradiol on sperm quality, fertilization, and embryo-larval survival of pejerrey fish (Odontesthes bonariensis)
Get PDF17β-Estradiol (E2) and synthetic 17α-Ethinylestradiol (EE2) are estrogenic compounds present in surface waters as a consequence of municipal sewage discharges. The aim of this study was to evaluate the effects of E2, EE2 and its mixtures on different reproductive parameters and embryo-larval survival in pejerrey fish (Odontesthes bonariensis). In order to analyze the effect of these compounds on sperm quality, fertilization%, embryo-larval survival (%), and the point of no return (PNR), different assays were performed using concentrations 175, 350, 700 and 1400ng/L of E2; 22.5, 45, 90 and 180ng/L of EE2 and mixtures M1 (175 E2+22.5 EE2, ng/L), M2 (350 E2+45 EE2, ng/L), M3 (700 E2+90 EE2, ng/L) and M4 (1400 E2+180 EE2 ng/L). No significant differences in motility parameters were observed between E2 and EE2 treatments and the control group. However, a significant decrease in motility% was recorded for all mixtures tested compared with the control samples. For fertilization%, only sperm activated with M4 showed a significant decrease compared with the control group. In the case of embryo survival, there was only a significant decrease in the highest concentration of EE2 compared with the control group. For the mixtures, M3 is the one that had the most adverse effect on embryo survival. In larval survival, there was a significant decrease in concentration 175 and 700ng/L of E2 compared with the control group. In EE2 treatments, the ones with a significant reduction in larval survival were concentration 45 and 90ng/L. And for the mixture treatments, M1, M3 and M4 had a significantly lower larval survival than the control group. In comparison to other treatments, M1 demonstrated a significant difference in PNR when compared with the control group. The results obtained demonstrated that the exposure to mixtures of E2 and EE2 affected fish sperm motility, fertilization% and, embryo and larval survival even at relevant environmental concentrations highlighting the necessity of considering the effects of pollutants mixtures in ecotoxicological studies.Fil: Garriz, Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Menendez Helman, Renata Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Laboratorio de Enzimología, Estrés Oxidativo y Metabolismo; ArgentinaFil: Miranda, Leandro Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentin
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