Treatment of congenital aortic valve stenosis: impact of the Ross operation.

GOAL: To evaluate the impact of the Ross operation, recently (1997) introduced in our unit, for the treatment of patients with congenital aortic valve stenosis. METHODS: The period from January 1997 to December 2000 was compared with the previous 5 years (1992-96). Thirty-seven children (< 16 yrs) and 49 young adults (16-50 yrs) with congenital aortic valve stenosis underwent one of these treatments: percutaneous balloon dilatation (PBD), aortic valve commissurotomy, aortic valve replacement and the Ross operation. The Ross operation was performed in 16 patients, mean age 24.5 yrs (range 9-46 yrs) with a bicuspid stenotic aortic valve, 7/10 adults with calcifications, 2/10 adults with previous aortic valve commissurotomy, 4/6 children with aortic regurgitation following PBD, and 1/6 children who had had a previous aortic valve replacement with a prosthetic valve and aortic root enlargement. RESULTS: PBD was followed by death in two neonates (fibroelastosis); all other children survived PBD. Although there were no deaths, PBD in adults was recently abandoned, owing to unfavourable results. Aortic valve commissurotomy showed good results in children (no deaths). Aortic valve replacement, although associated with good results (no deaths), has been recently abandoned in children in favour of the Ross operation. Over a mean follow-up of 16 months (2-40 months) all patients are asymptomatic following Ross operation, with no echocardiographic evidence of aortic valve regurgitation in 10/16 patients and with trivial regurgitation in 6/16 patients. CONCLUSIONS: The approach now for children and young adults with congenital aortic valve stenosis should be as follows: (1) PBD is the first choice in neonates and infants; (2) Aortic valve commissurotomy is the first choice for children, neonates and infants after failed PBD; (3) The Ross operation is increasingly used in children after failed PBD and in young adults, even with a calcified aortic valve.

3D visualization software to analyze topological outcomes of topoisomerase reactions.

The action of various DNA topoisomerases frequently results in characteristic changes in DNA topology. Important information for understanding mechanistic details of action of these topoisomerases can be provided by investigating the knot types resulting from topoisomerase action on circular DNA forming a particular knot type. Depending on the topological bias of a given topoisomerase reaction, one observes different subsets of knotted products. To establish the character of topological bias, one needs to be aware of all possible topological outcomes of intersegmental passages occurring within a given knot type. However, it is not trivial to systematically enumerate topological outcomes of strand passage from a given knot type. We present here a 3D visualization software (TopoICE-X in KnotPlot) that incorporates topological analysis methods in order to visualize, for example, knots that can be obtained from a given knot by one intersegmental passage. The software has several other options for the topological analysis of mechanisms of action of various topoisomerases.

SwissDock, a protein-small molecule docking web service based on EADock DSS.

Most life science processes involve, at the atomic scale, recognition between two molecules. The prediction of such interactions at the molecular level, by so-called docking software, is a non-trivial task. Docking programs have a wide range of applications ranging from protein engineering to drug design. This article presents SwissDock, a web server dedicated to the docking of small molecules on target proteins. It is based on the EADock DSS engine, combined with setup scripts for curating common problems and for preparing both the target protein and the ligand input files. An efficient Ajax/HTML interface was designed and implemented so that scientists can easily submit dockings and retrieve the predicted complexes. For automated docking tasks, a programmatic SOAP interface has been set up and template programs can be downloaded in Perl, Python and PHP. The web site also provides an access to a database of manually curated complexes, based on the Ligand Protein Database. A wiki and a forum are available to the community to promote interactions between users. The SwissDock web site is available online at http://www.swissdock.ch. We believe it constitutes a step toward generalizing the use of docking tools beyond the traditional molecular modeling community.

Mitral regurgitation.

Mitral regurgitation (MR) involves systolic retrograde flow from the left ventricle into the left atrium. While trivial MR is frequent in healthy subjects, moderate to severe MR constitutes the second most prevalent valve disease after aortic valve stenosis. Major causes of severe MR in Western countries include degenerative valve disease (myxomatous disease, flail leaflet, annular calcification) and ischaemic heart disease, while rheumatic disease remains a major cause of MR in developing countries. Chronic MR typically progresses insidiously over many years. Once established, however, severe MR portends a poor prognosis. The severity of MR can be assessed by various techniques, Doppler echocardiography being the most widely used. Mitral valve surgery is the only treatment of proven efficacy. It alleviates clinical symptoms and prevents ventricular dilatation and heart failure (or, at least, it attenuates further progression of these abnormalities). Valve repair significantly improves clinical outcomes compared with valve replacement, reducing mortality by approximately 70%. Reverse LV remodelling after valve repair occurs in half of patients with functional MR. Percutaneous, catheter-based to mitral valve repair is a novel approach currently under clinical scrutiny, with encouraging preliminary results. This modality may provide a valuable alternative to mitral valve surgery, especially in critically ill patients.

Fracture risk and zoledronic acid therapy in men with osteoporosis.

BACKGROUND: Fractures in men are a major health issue, and data on the antifracture efficacy of therapies for osteoporosis in men are limited. We studied the effect of zoledronic acid on fracture risk among men with osteoporosis. METHODS: In this multicenter, double-blind, placebo-controlled trial, we randomly assigned 1199 men with primary or hypogonadism-associated osteoporosis who were 50 to 85 years of age to receive an intravenous infusion of zoledronic acid (5 mg) or placebo at baseline and at 12 months. Participants received daily calcium and vitamin D supplementation. The primary end point was the proportion of participants with one or more new morphometric vertebral fractures over a period of 24 months. RESULTS: The rate of any new morphometric vertebral fracture was 1.6% in the zoledronic acid group and 4.9% in the placebo group over the 24-month period, representing a 67% risk reduction with zoledronic acid (relative risk, 0.33; 95% confidence interval, 0.16 to 0.70; P=0.002). As compared with men who received placebo, men who received zoledronic acid had fewer moderate-to-severe vertebral fractures (P=0.03) and less height loss (P=0.002). Fewer participants who received zoledronic acid had clinical vertebral or nonvertebral fractures, although this difference did not reach significance because of the small number of fractures. Bone mineral density was higher and bone-turnover markers were lower in the men who received zoledronic acid (P<0.05 for both comparisons). Results were similar in men with low serum levels of total testosterone. The zoledronic acid and placebo groups did not differ significantly with respect to the incidence of death (2.6% and 2.9%, respectively) or serious adverse events (25.3% and 25.2%). CONCLUSIONS: Zoledronic acid treatment was associated with a significantly reduced risk of vertebral fracture among men with osteoporosis. (Funded by Novartis Pharma; ClinicalTrials.gov number, NCT00439647.).

Crises as a disease of the body politick: a metaphor in the history of nineteenth century economics

This paper examines the use of the medical metaphor in the early theories of crises. It first considers the borrowing of medical terminology and generic references to disease which, notwithstanding their relatively trivial character, illustrate how crises were originally conceived as disturbances (often of a political nature) to a naturally healthy system. Then it shows how a more specific metaphor, the fever of speculation, shifted the emphasis by treating prosperity as the diseased phase, to which crises are a remedy. The metaphor of the epidemic spreading of the disease introduced the theme of the cumulative character of both upswing and downswing, while the similitude with intermittent fevers accounted for the recurring nature of crises. Finally, the paper examines how the medical reflections on the causality of diseases contributed to the epistemology of crises theory, and reflects on the metaphisical shift accompanying the transition from the theories of crises to the theories of cycles.

Whole-Body Vibration Training Elevates Creatine-Kinase Levels in Sedentary Subjects

METHODS: 20 inactive (10 male, 10 female) underwent a single typical WBV session, with a total of 27 minutes of exercise on an oscillating platform at 26 Hz, involving upper and lower body muscles. Each exercise lasted 90 seconds, with 40 seconds pauses inbetween. Muscle enzymes (CK, transaminase, LDH, troponin I) were measured before, at 24, 48 and 96 hours post exercise. Lactate was measured immediately after the session. Muscle aches were assessed during 4 days post-exercise.RESULTS: Subjects' mean age was 23.0 ± 3.5 (male), 22.4 ± 1.4 (female), BMI 22.8 ± 2.3 and 22.1 ± 1.9, and all had been inactive for at least 12 months. Post exercise lactatemia was 10.0 ± 2.4 and 6.9 ± 2.4. CK elevation was significant (at least doubling of baseline values) in 1 male and 4 female subjects, while they remained at baseline values for the remaining 15 subjects. One female subject peaked at 3520 U/l at 96 hours post exercise, and all but one peaked at the same late time. Troponin and CK-MB never increased. No correlation was found between muscle soreness and CK levels.CONCLUSIONS: WBV can elicit important anaerobic processes reflected by the high lactacidemia, and CK elevation was significant in 25 % of subjects, peaking at the fourth day after exercise for 80 % of those. Such exercises should not be regarded as trivial and "easy" as they are advertised, since they can provoke important anaerobia and CK elevation. Many fragile patients or patients treated for cardiovascular disease could benefit from WBV but it is important to recognise these potential effects, especially in those treated with statins, known to cause a myopathy and CK elevation. Before considering a side effect of an important therapeutic agent, doctors should be aware of the possible interaction with not-so-harmless exercising machines.

KnotProt: a database of proteins with knots and slipknots.

The protein topology database KnotProt, http://knotprot.cent.uw.edu.pl/, collects information about protein structures with open polypeptide chains forming knots or slipknots. The knotting complexity of the cataloged proteins is presented in the form of a matrix diagram that shows users the knot type of the entire polypeptide chain and of each of its subchains. The pattern visible in the matrix gives the knotting fingerprint of a given protein and permits users to determine, for example, the minimal length of the knotted regions (knot's core size) or the depth of a knot, i.e. how many amino acids can be removed from either end of the cataloged protein structure before converting it from a knot to a different type of knot. In addition, the database presents extensive information about the biological functions, families and fold types of proteins with non-trivial knotting. As an additional feature, the KnotProt database enables users to submit protein or polymer chains and generate their knotting fingerprints.

Postoperative delirium. Part 1: pathophysiology and risk factors.

Delirium presents clinically with differing subtypes ranging from hyperactive to hypoactive. The clinical presentation is not clearly linked to specific pathophysiological mechanisms. Nevertheless, there seem to be different mechanisms that lead to delirium; for example the mechanisms leading to alcohol-withdrawal delirium are different from those responsible for postoperative delirium. In many forms of delirium, the brain's reaction to a peripheral inflammatory process is considered to be a pathophysiological key element and the aged brain seems to react more markedly to a peripheral inflammatory stimulus than a younger brain. The effects of inflammatory mediators on the brain include changes in neurotransmission and apoptosis. On a neurotransmitter level, impaired cholinergic transmission and disturbances of the intricate interactions between dopamine, serotonin and acetylcholine seem to play an important role in the development of delirium. The risk factors for delirium are categorised as predisposing or precipitating factors. In the presence of many predisposing factors, even trivial precipitating factors may trigger delirium, whereas in patients without or with only a few predisposing factors, a major precipitating insult is necessary to trigger delirium. Well documented predisposing factors are age, medical comorbidities, cognitive, functional, visual and hearing impairment and institutional residence. Important precipitating factors apart from surgery are admission to an ICU, anticholinergic drugs, alcohol or drug withdrawal, infections, iatrogenic complications, metabolic derangements and pain. Scores to predict the risk of delirium based on four or five risk factors have been validated in surgical patients.

Data-based approach for developing a physical activity frequency questionnaire.

Measurement of total energy expenditure may be crucial to an understanding of the relation between physical activity and disease and in order to frame public health intervention. To devise a self-administered physical activity frequency questionnaire (PAFQ), the following data-based approach was used. A 24-hour recall was administered to a random sample of 919 adult residents of Geneva, Switzerland. The data obtained were used to establish the list of activities (and their median duration) that contributed to 95% of the energy expended, separately for men and women. Activities that were trivial for the whole sample but that contributed to > or = 10% of an individual's energy expenditure were also selected. The final PAFQ lists 70 activities or group of activities with their typical duration. About 20 minutes are required for respondents to indicate the number of days and the number of hours per day that they performed each activity. The PAFQ method was validated against a heart rate monitor, a more objective method. The total energy estimated by the PAFQ in 41 volunteers correlated well (r = 0.76) with estimates using a heart rate monitor. The authors conclude that the design of their self-administered physical activity frequency questionnaire based on data from 24-hour recall appeared to accurately estimate energy expenditure.

Modeling complex wells with the multi-scale finite-volume method

In this paper, an extension of the multi-scale finite-volume (MSFV) method is devised, which allows to Simulate flow and transport in reservoirs with complex well configurations. The new framework fits nicely into the data Structure of the original MSFV method,and has the important property that large patches covering the whole well are not required. For each well. an additional degree of freedom is introduced. While the treatment of pressure-constraint wells is trivial (the well-bore reference pressure is explicitly specified), additional equations have to be solved to obtain the unknown well-bore pressure of rate-constraint wells. Numerical Simulations of test cases with multiple complex wells demonstrate the ability of the new algorithm to capture the interference between the various wells and the reservoir accurately. (c) 2008 Elsevier Inc. All rights reserved.

De la recommandation d'un dépistage à son (non) implantation: le cas de l'anévrisme de l'aorte abdominale. [From guidelines for screening to their (poor) implementation: the case of the abdominal aortic aneurysm].

Suite à des essais cliniques randomisés démontrant l'efficacité du dépistage de l'anévrisme de l'aorte abdominale (AAA) par échographie, plusieurs recommandations ont été publiées dans de nombreux pays en faveur du dépistage dans une partie de la population générale. De plus, au-delà de la rupture aortique, le dépistage d'un petit AAA semble être une bonne occasion d'appliquer les stratégies de prévention secondaire, permettant une amélioration globale du pronostic cardiovasculaire du patient. Ces recommandations sont cependant peu suivies; les campagnes de dépistage systématique sont rares, laissant la responsabilité du dépistage au médecin généraliste. Cet article se propose de discuter les raisons de la non-implantation du dépistage de l'AAA. [Abstract] Following the evidence of benefits of ultrasound screening for abdominal aorta aneurysms (AAA), several guidelines support this screening in population. Beyond the prompt diagnosis of AAA prior to its rupture of grim vital prognosis, small AAA can beconsidered as a prognostic marker for cardiovascular diseases (CVD). Yet, its detection is an opportunity for secondary prevention to reduce CVD mortality. Despite, these guidelines are poorly applied: systematic screening campaigns are infrequent, making the screening of family physicians responsibility. While the major benefit from this screening strategy is to reduce AAA-related death (but only trivial effect on long-term total mortality), this explains only partially the lack of guidelines implementation. The reasons of the poor implementation of these guidelines are discussed herein.

Multidimensionnalité des violences envers les femmes. La Suisse en regard des États-Unis: pertinence et validité d'une comparaison

Summary : International comparisons in the area of victimization, particularly in the field of violence against women, are fraught with methodological problems that previous research has not systematically addressed, and whose answer does not seem to be agreed up~n. For obvious logistic and financial reasons, international studies on violence against women (i.e. studies that administer the same instrument in different countries). are seldom; therefore, researchers are bound to resort to secondary comparisons. Many studies simply juxtapose their results to the ones of previous wòrk or to findings obtained in different contexts, in order to offer an allegedly comparative perspective to their conclusions. If, most of the time, researchers indicate the methodological limitations of a direct comparison, it is not rare that these do not result in concrete methodological controls. Yet, many studies have shown the influence of surveys methodological parameters on findings, listing recommendations fora «best practice» of research. Although, over the past decades, violence against women surveys have become more and more similar -tending towards a sort of uniformization that could be interpreted as a passive consensus -these instruments retain more or less subtle differences that are still susceptible to influence the validity of a comparison. Yet, only a small number of studies have directly worked on the comparability of violence against women data, striving to control the methodological parameters of the surveys in order to guarantee the validity of their comparisons. The goal of this work is to compare data from two national surveys on violence against women: the Swiss component of the International Violence Against Women Survey [CH-IVAWS] and the National Violence Against Women Survey [NVAWS] administered in the United States. The choice of these studies certainly ensues from the author's affiliations; however, it is far from being trivial. Indeed, the criminological field currently endows American and Anglo-Saxon literature with a predominant space, compelling researchers from other countries to almost do the splits to interpret their results in the light of previous work or to develop effective interventions in their own context. Turning to hypotheses or concepts developed in a specific framework inevitably raises the issue of their applicability to another context, i.e. the Swiss context, if not at least European. This problematic then takes on an interest that goes beyond the particular topic of violence against women, adding to its relevance. This work articulates around three axes. First, it shows the way survey characteristics influence estimates. The comparability of the nature of the CH-IVAWS and NVAWS, their sampling design and the characteristics of their administration are discussed. The definitions used, the operationalization of variables based on comparable items, the control of reference periods, as well as the nature of the victim-offender relationship are included among controlled factors. This study establishes content validity within and across studies, presenting a systematic process destined to maximize the comparability of secondary data. Implications of the process are illustrated with the successive presentation of comparable and non-comparable operationalizations of computed variables. Measuring violence against. women in Switzerland and the United-States, this work compares the prevalence of different forms (threats, physical violence and sexual violence) and types of violence (partner and nonpartner violence). Second, it endeavors to analyze concepts of multivictimization (i.e. experiencing different forms of victimization), repeat victimization (i.e. experiencing the same form of violence more than once), and revictimization (i.e. the link between childhood and adulthood victimization) in a comparative -and comparable -approach. Third, aiming at understanding why partner violence appears higher in the United States, while victims of nonpartners are more frequent in Switzerland, as well as in other European countries, different victimization correlates are examined. This research contributes to a better understanding of the relevance of controlling methodological parameters in comparisons across studies, as it illustrates, systematically, the imposed controls and their implications on quantitative data. Moreover, it details how ignoring these parameters might lead to erroneous conclusions, statistically as well as theoretically. The conclusion of the study puts into a wider perspective the discussion of differences and similarities of violence against women in Switzerland and the United States, and integrates recommendations as to the relevance and validity of international comparisons, whatever the'field they are conducted in. Résumé: Les comparaisons internationales dans le domaine de la victimisation, et plus particulièrement en ce qui concerne les violences envers les femmes, se caractérisent par des problèmes méthodologiques que les recherches antérieures n'ont pas systématiquement adressés, et dont la réponse ne semble pas connaître de consensus. Pour des raisons logistiques et financières évidentes, les études internationales sur les violences envers les femmes (c.-à-d. les études utilisant un même instrument dans différents pays) sont rares, aussi les chercheurs sont-ils contraints de se tourner vers des comparaisons secondaires. Beaucoup de recherches juxtaposent alors simplement leurs résultats à ceux de travaux antérieurs ou à des résultats obtenus dans d'autres contextes, afin d'offrir à leurs conclusions une perspective prétendument comparative. Si, le plus souvent, les auteurs indiquent les limites méthodologiques d'une comparaison directe, il est fréquent que ces dernières ne se traduisent pas par des contrôles méthodologiques concrets. Et pourtant, quantité de travaux ont mis en évidence l'influence des paramètres méthodologiques des enquêtes sur les résultats obtenus, érigeant des listes de recommandations pour une «meilleure pratique» de la recherche. Bien que, ces dernières décennies, les sondages sur les violences envers les femmes soient devenus de plus en plus similaires -tendant, vers une certaine uniformisation que l'on peut interpréter comme un consensus passif-, il n'en demeure pas moins que ces instruments possèdent des différences plus ou moins subtiles, mais toujours susceptibles d'influencer la validité d'une comparaison. Pourtant, seules quelques recherches ont directement travaillé sur la comparabilité des données sur les violences envers les femmes, ayant à coeur de contrôler les paramètres méthodologiques des études utilisées afin de garantir la validité de leurs comparaisons. L'objectif de ce travail est la comparaison des données de deux sondages nationaux sur les violences envers les femmes: le composant suisse de l'International Violence Against Women Survey [CHIVAWSj et le National Violence Against Women Survey [NVAWS) administré aux États-Unis. Le choix de ces deux études découle certes des affiliations de l'auteure, cependant il est loin d'être anodin. Le champ criminologique actuel confère, en effet, une place prépondérante à la littérature américaine et anglo-saxonne, contraignant ainsi les chercheurs d'autres pays à un exercice proche du grand écart pour interpréter leurs résultats à la lumière des travaux antérieurs ou développer des interventions efficaces dans leur propre contexte. Le fait de recourir à des hypothèses et des concepts développés dans un cadre spécifique pose inévitablement la question de leur applicabilité à un autre contexte, soit ici le contexte suisse, sinon du moins européen. Cette problématique revêt alors un intérêt qui dépasse la thématique spécifique des violences envers les femmes, ce qui ajoute à sa pertinence. Ce travail s'articule autour de trois axes. Premièrement, il met en évidence la manière dont les caractéristiques d'un sondage influencent les estimations qui en découlent. La comparabilité de la nature du CH-IVAWS et du NVAWS, de leur processus d'échantillonnage et des caractéristiques de leur administration est discutée. Les définitions utilisées, l'opérationnalisation des variables sur la base d'items comparables, le contrôle des périodes de référence, ainsi que la nature de la relation victime-auteur figurent également parmi les facteurs contrôlés. Ce travail établit ainsi la validité de contenu intra- et inter-études, offrant un processus systématique destiné à maximiser la comparabilité des données secondaires. Les implications de cette démarche sont illustrées avec la présentation successive d'opérationnalisations comparables et non-comparables des variables construites. Mesurant les violences envers les femmes en Suisse et aux États-Unis, ce travail compare la prévalence de plusieurs formes (menaces, violences physiques et violences sexuelles) et types de violence (violences partenaires et non-partenaires). 11 s'attache également à analyser les concepts de multivictimisation (c.-à-d. le fait de subir plusieurs formes de victimisation), victimisation répétée (c.-à.-d. le fait de subir plusieurs incidents de même forme) et revictimisation (c.-à-d. le lien entre la victimisation dans l'enfance et à l'âge adulte) dans une approche comparative - et comparable. Dans un troisième temps, cherchant à comprendre pourquoi la violence des partenaires apparaît plus fréquente aux États-Unis, tandis que les victimes de non-partenaires sont plus nombreuses en Suisse, et dans d'autres pays européens, différents facteurs associés à la victimisation sont évalués. Cette recherche participe d'une meilleure compréhension de la pertinence du contrôle des paramètres méthodologiques dans les comparaisons entre études puisqu'elle illustre, pas à pas, les contrôles imposés et leurs effets sur les données quantitatives, et surtout comment l'ignorance de ces paramètres peut conduire à des conclusions erronées, tant statistiquement que théoriquement. La conclusion replace, dans un contexte plus large, la discussion des différences et des similitudes observées quant à la prévalence des violences envers les femmes en Suisse et aux États-Unis, et intègre des recommandations quant à la pertinence et à la validité des comparaisons internationales, cela quel que soit le domaine considéré.

Mynodbcsv: Lightweight Zero-Config Database Solution for Handling Very Large CSV Files.

Volumes of data used in science and industry are growing rapidly. When researchers face the challenge of analyzing them, their format is often the first obstacle. Lack of standardized ways of exploring different data layouts requires an effort each time to solve the problem from scratch. Possibility to access data in a rich, uniform manner, e.g. using Structured Query Language (SQL) would offer expressiveness and user-friendliness. Comma-separated values (CSV) are one of the most common data storage formats. Despite its simplicity, with growing file size handling it becomes non-trivial. Importing CSVs into existing databases is time-consuming and troublesome, or even impossible if its horizontal dimension reaches thousands of columns. Most databases are optimized for handling large number of rows rather than columns, therefore, performance for datasets with non-typical layouts is often unacceptable. Other challenges include schema creation, updates and repeated data imports. To address the above-mentioned problems, I present a system for accessing very large CSV-based datasets by means of SQL. It's characterized by: "no copy" approach - data stay mostly in the CSV files; "zero configuration" - no need to specify database schema; written in C++, with boost [1], SQLite [2] and Qt [3], doesn't require installation and has very small size; query rewriting, dynamic creation of indices for appropriate columns and static data retrieval directly from CSV files ensure efficient plan execution; effortless support for millions of columns; due to per-value typing, using mixed text/numbers data is easy; very simple network protocol provides efficient interface for MATLAB and reduces implementation time for other languages. The software is available as freeware along with educational videos on its website [4]. It doesn't need any prerequisites to run, as all of the libraries are included in the distribution package. I test it against existing database solutions using a battery of benchmarks and discuss the results.

Information sharing and social network dynamics : a coevolutionary approach

The capacity to interact socially and share information underlies the success of many animal species, humans included. Researchers of many fields have emphasized the evo¬lutionary significance of how patterns of connections between individuals, or the social networks, and learning abilities affect the information obtained by animal societies. To date, studies have focused on the dynamics either of social networks, or of the spread of information. The present work aims to study them together. We make use of mathematical and computational models to study the dynamics of networks, where social learning and information sharing affect the structure of the population the individuals belong to. The number and strength of the relationships between individuals, in turn, impact the accessibility and the diffusion of the shared information. Moreover, we inves¬tigate how different strategies in the evaluation and choice of interacting partners impact the processes of knowledge acquisition and social structure rearrangement. First, we look at how different evaluations of social interactions affect the availability of the information and the network topology. We compare a first case, where individuals evaluate social exchanges by the amount of information that can be shared by the partner, with a second case, where they evaluate interactions by considering their partners' social status. We show that, even if both strategies take into account the knowledge endowments of the partners, they have very different effects on the system. In particular, we find that the first case generally enables individuals to accumulate higher amounts of information, thanks to the more efficient patterns of social connections they are able to build. Then, we study the effects that homophily, or the tendency to interact with similar partners, has on knowledge accumulation and social structure. We compare the case where individuals who know the same information are more likely to learn socially from each other, to the opposite case, where individuals who know different information are instead more likely to learn socially from each other. We find that it is not trivial to claim which strategy is better than the other. Depending on the possibility of forgetting information, the way new social partners can be chosen, and the population size, we delineate the conditions for which each strategy allows accumulating more information, or in a faster way For these conditions, we also discuss the topological characteristics of the resulting social structure, relating them to the information dynamics outcome. In conclusion, this work paves the road for modeling the joint dynamics of the spread of information among individuals and their social interactions. It also provides a formal framework to study jointly the effects of different strategies in the choice of partners on social structure, and how they favor the accumulation of knowledge in the population. - La capacité d'interagir socialement et de partager des informations est à la base de la réussite de nombreuses espèces animales, y compris les humains. Les chercheurs de nombreux domaines ont souligné l'importance évolutive de la façon dont les modes de connexions entre individus, ou réseaux sociaux et les capacités d'apprentissage affectent les informations obtenues par les sociétés animales. À ce jour, les études se sont concentrées sur la dynamique soit des réseaux sociaux, soit de la diffusion de l'information. Le présent travail a pour but de les étudier ensemble. Nous utilisons des modèles mathématiques et informatiques pour étudier la dynamique des réseaux, où l'apprentissage social et le partage d'information affectent la structure de la population à laquelle les individus appartiennent. Le nombre et la solidité des relations entre les individus ont à leurs tours un impact sur l'accessibilité et la diffusion de l'informa¬tion partagée. Par ailleurs, nous étudions comment les différentes stratégies d'évaluation et de choix des partenaires d'interaction ont une incidence sur les processus d'acquisition des connaissances ainsi que le réarrangement de la structure sociale. Tout d'abord, nous examinons comment des évaluations différentes des interactions sociales influent sur la disponibilité de l'information ainsi que sur la topologie du réseau. Nous comparons un premier cas, où les individus évaluent les échanges sociaux par la quantité d'information qui peut être partagée par le partenaire, avec un second cas, où ils évaluent les interactions en tenant compte du statut social de leurs partenaires. Nous montrons que, même si les deux stratégies prennent en compte le montant de connaissances des partenaires, elles ont des effets très différents sur le système. En particulier, nous constatons que le premier cas permet généralement aux individus d'accumuler de plus grandes quantités d'information, grâce à des modèles de connexions sociales plus efficaces qu'ils sont capables de construire. Ensuite, nous étudions les effets que l'homophilie, ou la tendance à interagir avec des partenaires similaires, a sur l'accumulation des connaissances et la structure sociale. Nous comparons le cas où des personnes qui connaissent les mêmes informations sont plus sus¬ceptibles d'apprendre socialement l'une de l'autre, au cas où les individus qui connaissent des informations différentes sont au contraire plus susceptibles d'apprendre socialement l'un de l'autre. Nous constatons qu'il n'est pas trivial de déterminer quelle stratégie est meilleure que l'autre. En fonction de la possibilité d'oublier l'information, la façon dont les nouveaux partenaires sociaux peuvent être choisis, et la taille de la population, nous déterminons les conditions pour lesquelles chaque stratégie permet d'accumuler plus d'in¬formations, ou d'une manière plus rapide. Pour ces conditions, nous discutons également les caractéristiques topologiques de la structure sociale qui en résulte, les reliant au résultat de la dynamique de l'information. En conclusion, ce travail ouvre la route pour la modélisation de la dynamique conjointe de la diffusion de l'information entre les individus et leurs interactions sociales. Il fournit également un cadre formel pour étudier conjointement les effets de différentes stratégies de choix des partenaires sur la structure sociale et comment elles favorisent l'accumulation de connaissances dans la population.