1,720,957 research outputs found
Seasonal pattern of phototherapy: a study in the Sardinian population
No full textThe relationship between season of birth and human diseases is well known and it has been suggested that such a relationship could be mediated by seasonal and environmental effects on early events of extrauterine life. In this context the physiological increase of bilirubin occurring in all infants during the neonatal period may be of paramount importance. Indeed, recent studies suggest a beneficial action of bilirubin in the early stages of extrauterine life due to its protective action against secondary oxidants. The newborn infant is particularly sensible to oxidative damage, thus seasonal variation of bilirubin level in the first few days of life could influence further development and susceptibility to pathological manifestations. In the present paper we have analysed the seasonal effect on the level of the serum bilirubin during the neonatal period by an analysis of the incidence of phototherapy in a sample of 5540 infants born consecutively in the population of Sassari during the years 1993-96. The proportion of infants undergoing phototherapy for neonatal hyperbilirubinemia is lower in those without glucose-6-phosphate-dehydrogenaser (G-6-PD) deficiency than in those with G-6-PD deficiency and in both categories the proportion is lower in females than in males. A highly significant association between the date of birth and the proportion of infants undergoing phototherapy has been observed in males without G-6-PD deficiency. The maximum incidence of phototherapy has been observed in the period May-August. A Fourier analysis carried out on these infants has shown the presence of two main components (harmonics) contributing to the seasonal cycle and corresponding respectively to a one year and to a two years period
Cyclic seasonal variation of G-6-PD deficiency in newborn infants from Sardinia
No full textGlucose-6-Phosphate Dehydrogenase has been studied in 5267 consecutive newborn infants from Sardinian population during a four years period. The proportion of G-6-PD deficient female infants is much higher in those conceived in the winter-spring than among those conceived in summer-autumn, resulting in a lower sex ratio among G-6-PD deficient infants conceived in winter-spring as compared to G-6-PD deficient infants conceived in the summer-autumn. The overall frequency of the gene for G-6-PD deficiency is much lower in infants conceived in the summer period than in infants conceived in the other seasons. A greater reproductive efficiency of G-6-PD deficient males in the winter-spring season and/or some effect at post zygotic level favouring the survival of heterozygous G-6-PD deficient females conceived in the winter-spring period could contribute to the pattern described. Fresh vegetables containing oxidative substances are more abundant in the spring time. These substances may interact with seasonal reproductive cycles influencing reproduction efficiency of G-6-PD deficient males and/or the relative survival rate of heterozygous female embryos
Genotypes of cytosolic low-molecular-weight protein-tyrosine-phosphatase correlate with age at onset of type 1 diabetes in a sex-specific manner
No full textWe investigated the possible role of cytosolic low-molecular-weight protein-tyrosine-phosphatase (cLMWPTP or acid phosphatase locus 1 [ACP1]) in the mediation of age at onset of type 1 diabetes. ACP1 is an enzyme involved in signal transduction of T-cell receptors, insulin, and other growth factor receptors. We studied acid phosphatase polymorphism in 189 consecutive children with type 1 diabetes admitted to the Pediatric Clinic of Sassari University (Sardinia) and in 86 adolescent patients with recently diagnosed type 1 diabetes from continental Italy. In both populations, females with medium-high activity acid phosphatase genotypes had onset of disease significantly earlier than males. The data suggest that acid phosphatase genotype affects the age of onset and probably also the sex ratio in type 1 diabetes. Sex hormones might modulate the susceptibility to autoimmune diseases, including type 1 diabetes, through the influence of signal transduction pathways involved in immune functions. Elucidation of the molecular basis for gender differences in the course and severity of type 1 diabetes could have important implications for treatment as well, because there might be gender-specific effects in the response to immunotherapy
Rh system and intrauterine growth. Interaction with season of birth
No full textBased on the hypothesis that maternal-fetal genetic differences in membrane transport and signal transduction may influence intrauterine development, the recent acquisition on transport function of Rh protein prompted us to study the relationship between joint maternal-fetal Rh phenotype and birth weight. Considering that metabolic effect of maternal-fetal competition could be amplified by environmental conditions, we have investigated possible seasonal effects on such relationship. We have studied 5291 infants born in Sardinia in the period January 1993-December 1996 and 984 infants born in Rome during 1996. In Rh(-) mothers there is a significant association between season of birth and birth weight that shows the highest mean value in infants born in autumn (i.e. conceived in winter). The association is much more evident in male than in female infants. In male infants from Rh(-) mothers, the association between birth weight and season is significant in Rh(+) male newborns only. Recent observations by our group in NIDDM suggest that glucose transport in RBC may be related to D protein, thus we propose an interpretation of the present observation in terms of transport function. When the density of D protein in the infant is greater than in the mother, the balance is in favour of the infant who may attain a significant developmental advantage when conceived in the cold season
Evidence of decreased fertility in women carrying the gene for G6PD deficiency: a study in the Sardinian population
No full textThe current trend toward reduced feritility and delayed childbearing has stimulated an interest in the genetic and environmental factors capable of modifying fertility. The evaluation of fertility in GOD-deficient females is of great theoretical interest in view of the proposed heterozygote advantage of GOD deficiency in malarial environments. Toncheva and Tzoneva have reported population data from Bulgaria suggesting decreased fertility of women carrying the risk allele for G6PD deficiency. We have applied a model of maternal-age related differences within the distribution of 'fertility-types' among women, described by Gimelfarb and Bottini (1989) to a sample of 5182 Sardinian mothers. Mothers of infants with G6PD deficiency are underrepresented in the group of women having children at younger ages, suggesting a reduction of so-called 'natural fertility' among women carrying the risk allele for GOD deficiency. Female infants with G6PD deficiency from young mothers have a lower birth weight compared to infants without GOD deficiency from older mothers, suggesting that in younger mothers there is a negative effect of GOD deficiency on intrauterine growth
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
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