Modelling Influence and Opinion Evolution in Online Collective Behaviour.

Opinion evolution and judgment revision are mediated through social influence. Based on a large crowdsourced in vitro experiment (n = 861), it is shown how a consensus model can be used to predict opinion evolution in online collective behaviour. It is the first time the predictive power of a quantitative model of opinion dynamics is tested against a real dataset. Unlike previous research on the topic, the model was validated on data which did not serve to calibrate it. This avoids to favor more complex models over more simple ones and prevents overfitting. The model is parametrized by the influenceability of each individual, a factor representing to what extent individuals incorporate external judgments. The prediction accuracy depends on prior knowledge on the participants' past behaviour. Several situations reflecting data availability are compared. When the data is scarce, the data from previous participants is used to predict how a new participant will behave. Judgment revision includes unpredictable variations which limit the potential for prediction. A first measure of unpredictability is proposed. The measure is based on a specific control experiment. More than two thirds of the prediction errors are found to occur due to unpredictability of the human judgment revision process rather than to model imperfection

Weaning practices in phenylketonuria vary between health professionals in Europe

Background: In phenylketonuria (PKU), weaning is considered more challenging when compared to feeding healthy infants. The primary aim of weaning is to gradually replace natural protein from breast milk or standard infant formula with solids containing equivalent phenylalanine (Phe). In addition, a Phe-free second stage L-amino acid supplement is usually recommended from around 6 months to replace Phe-free infant formula. Our aim was to assess different weaning approaches used by health professionals across Europe. Methods: A cross sectional questionnaire (survey monkey (R)) composed of 31 multiple and single choice questions was sent to European colleagues caring for inherited metabolic disorders (IMD). Centres were grouped into geographical regions for analysis. Results: Weaning started at 17-26 weeks in 85% (n=81/95) of centres, > 26 weeks in 12% (n=11/95) and 26 weeks. First solids were mainly low Phe vegetables (59%, n=56/95) and fruit (34%, n=32/95). A Phe exchange system to allocate dietary Phe was used by 52% (n=49/95) of centres predominantly from Northern and Southern Europe and 48% (n=46/95) calculated most Phe containing food sources (all centres in Eastern Europe and the majority from Germany and Austria). Some centres used a combination of both methods. A second stage Phe-free L-amino acid supplement containing a higher protein equivalent was introduced by 41% (n=39/95) of centres at infant age 26-36 weeks (mainly from Germany, Austria, Northern and Eastern Europe) and 37% (n=35/95) at infant age > 1y mainly from Southern Europe. 53% (n=50/95) of centres recommended a second stage Phe-free L-amino acid supplement in a spoonable or semi-solid form. Conclusions: Weaning strategies vary throughout European PKU centres. There is evidence to suggest that different infant weaning strategies may influence longer term adherence to the PKU diet or acceptance of Phe-free L-amino acid supplements; rendering prospective long-term studies important. It is essential to identify an effective weaning strategy that reduces caregiver burden but is associated with acceptable dietary adherence and optimal infant feeding development.Peer reviewe

Early feeding practices in infants with phenylketonuria across Europe

Background: In infants with phenylketonuria (PKU), dietary management is based on lowering and titrating phenylalanine (Phe) intake from breast milk or standard infant formula in combination with a Phe-free infant formula in order to maintain blood Phe levels within target range. Professionals use different methods to feed infants with PKU and our survey aimed to document practices across Europe. Methods: We sent a cross sectional, survey monkey (R) questionnaire to European health professionals working in IMD. It contained 31 open and multiple-choice questions. The results were analysed according to different geographical regions. Results: Ninety-five centres from 21 countries responded. Over 60% of centres commenced diet in infants by age 10 days, with 58% of centres implementing newborn screening by day 3 post birth. At diagnosis, infant hospital admission occurred in 61% of metabolic centres, mainly in Eastern, Western and Southern Europe. Breastfeeding fell sharply following diagnosis with only 30% of women still breast feeding at 6 months. 53% of centres gave pre-measured Phe-free infant formula before each breast feed and 23% alternated breast feeds with Phe-free infant formula. With standard infant formula feeds, measured amounts were followed by Phe-free infant formula to satiety in 37% of centres (n = 35/95), whereas 44% (n = 42/95) advised mixing both formulas together. Weaning commenced between 17 and 26 weeks in 85% centres, >= 26 weeks in 12% and <17 weeks in 3%. Discussion: This is the largest European survey completed on PKU infant feeding practices. It is evident that practices varied widely across Europe, and the practicalities of infant feeding in PKU received little focus in the PKU European Guidelines (2017). There are few reports comparing different feeding techniques with blood Phe control, Phe fluctuations and growth. Controlled prospective studies are necessary to assess how different infant feeding practices may influence longer term feeding development.Peer reviewe

Retrospective assessment of the influence of gestational age on the first trimester medical abortion efficiency

peer reviewedThere are two methods of abortion : the medical and the surgical methods, each with its own specific benefits. Theoretically, the limit of medical abortion gestational age is 7 weeks of amenorrhea. However, since 2011, our university department provides the opportunity of a drug regimen until 9 weeks of amenorrhea. This paper describes the results of a retrospective study which covers 804 patients who were submitted to a medical abortion with gestational ages of 6 to 9 weeks. The purpose is to investigate the efficiency of the medical approach up to 9 weeks and to assess the drug dose required according to the term of pregnancy. Our work shows an efficiency of 95 % of medical abortion up to 9 weeks gestation, with no significant variation with the gestational age. However, maintaining this level of efficiency during the progress of pregnancy requires an increase of the administered doses of misoprostol. In addition, there is a significant increase in the use of analgesics. The medical abortion procedure remains effective until 9 weeks of gestation. This pharmacological approach reduces the risks induced, in the short and long term by the surgical procedure

Replication Data for: Ideological Scaling of Social Media Users. A Dynamic Lexicon Approach

Words matter in politics. The rhetoric that political elites employ structures civic discourse. The emergence of social media platforms as a medium of politics has enabled ordinary citizens to express their ideological inclinations by adopting the lexicon of political elites. This avails to researchers a rich new source of data in the study of political ideology. However, existing ideological text-scaling methods fail to produce meaningful inferences when applied to the short, informal style of textual content that is characteristic of social media platforms such as Twitter. This paper introduces the first viable approach to the estimation of individual-level ideological positions derived from social media content. This method allows us to position social media users---be they political elites, parties, or citizens---along a shared ideological dimension. We validate the proposed method by demonstrating correlation with existing measures of ideology across various political contexts and multiple languages. We further demonstrate the ability of ideological estimates to capture derivative signal by predicting out-of-sample, individual-level voting intentions. We posit that social media data can, when properly modeled, better capture derivative signal than discrete scales used in more traditional survey instruments

Illustration of the shift applied to the synthetic judgment in order to preserve the distances between initial judgments.

<p>The shift made by the participant in the first round was synthetically applied to all other initial judgments. The intrinsic variation in judgment revision is the distance between second round judgments, reduced by the shift in initial judgments. The dotted cross is not a judgment and is only displayed to show how the second round intrinsic variation is computed using the initial shift. All shifts are equal. The same shift is also applied to all other second round judgments, and used to compute final round intrinsic variations.</p