1,720,969 research outputs found

    The role of Akt signalling in the mammalian ovary

    Full text link
    The serine/threonine protein kinase Akt is involved in many cellular processes including cell growth, survival, proliferation and metabolism. Akt activity is modulated downstream of phosphatidylinositol-3-kinase (PI3K) in response to different extracellular stimuli. In the mammalian ovary, Akt collaborates with other kinases in the regulation of coordinate follicle and oocyte development. Akt determines the pool of primordial follicles and the transition from quiescent to growing phase. In addition, the kinase modulates granulosa cell apoptosis throughout folliculogenesis. In oocytes Akt participates in the control of meiosis resumption and, at metaphase II stage, regulates polar body emission and spindle organization. Its inhibition negatively affects preimplantation embryo development. As a consequence of such a central role, Akt dysregulation is associated with several human diseases including infertility and ovarian cancer.[...

    Going Beyond Counting First Authors in Author Co-citation Analysis

    Full text link
    The 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

    Basso peso alla nascita, abitudini di vita delle madri in gravidanza e consumo di acque sottoposte a clorazione

    No full text
    Numerous environmental factors such as smoking habits, alcohol intake, economic and social status, and by-product chlorination present in drinking water can determine adverse pregnancy outcomes like a low weight birth, small for gestational age or preterm delivery. In 1998 the Italian Ministry of University and Scientific Technological Research (MURST) has financed a multicentric study in order to evaluate the association between exposure to by-products chlorination in drinking water during pregnancy and adverse pregnancy outcomes at birth such as preterm delivery and low birth weight. We describe the socio demographics characteristics, personal habits and the health status during pregnancy and exposure to the VOX of 171 women recruited from the Research Unit of Rome and L'Aquila. A case control study with incident cases was performed. Exposure to Chlorination By Products (CBP) and confounding factors for studied outcomes, were assessed by a validated questionnaire. At the same time, collection and analysis of 124 tap water samples were carried out directly at women's home. No association was found between CBPs level and low birth weight or preterm delivery. We found an excess risk statistically significantly between preterm delivery and hypertension (OR = 5.06; IC 95% = 1.70-15.44) an excess risk statistically significantly between low birth weight and smokers (OR = 3.43, IC 95% = 1.15-10.26). The CBPs levels were rather low (range cases = 0.09-6.28 microg/L; range controls = 0.01-6.44 microg/L). The results confirm the literature data and the validity of the epidemiological method adopted. The low CBPs levels, under the Law level, are probably imputable to the good quality of sorgive waters. Considering the CBPs level temporal variability in chlorinated waters, is to be hoped a careful and continues surveillance of the CBPs spike levels for better exposure assessment.Numerous environmental factors such as smoking habits, alcohol intake, economic and social status, and by-product chlorination present in drinking water can determine adverse pregnancy outcomes like a low weight birth, small for gestational age or preterm delivery. In 1998 the Italian Ministry of University and Scientific Technological Research (MURST) has financed a multicentric study in order to evaluate the association between exposure to by-products chlorination in drinking water during pregnancy and adverse pregnancy outcomes at birth such as preterm delivery and low birth weight. We describe the socio demographics characteristics, personal habits and the health status during pregnancy and exposure to the VOX of 171 women recruited from the Research Unit of Rome and L'Aquila. A case control study with incident cases was performed. Exposure to Chlorination By Products (CBP) and confounding factors for studied outcomes, were assessed by a validated questionnaire. At the same time,

    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 link
    We 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
    corecore