Three essays on gender differences in tie formation and network returns

L'inégalité de genre dans les contextes professionnels et organisationnels a été étudiée sous différents angles. Les causes sous-jacentes des différences de genre et leur impact sur l'inégalité ont été largement débattus. Cette thèse envisage la problématique des différences de genre au prisme des dynamiques de réseaux… Les stéréotypes suscitent des attentes spécifiques pour les individus en fonction de leur genre, ce qui peut influencer leurs comportements et les jugements d'autrui à leur égard. Cette thèse explore comment les stéréotypes de genre affectent les comportements des hommes et des femmes dans leurs relations sociales et comment ces comportements, en retour, contribuent aux différences de genre dans les dynamiques de réseau. Les stéréotypes de genre sont ancrés dans l'allocation historique des rôles sociétaux entre les hommes et les femmes, qui ont imposé le respect de certaines caractéristiques : les femmes ont été assignées à des tâches domestiques et sont censées présenter des traits communautaires tels que la bienveillance, tandis que les hommes se voient assigner des responsabilités liées au travail et sont censés présenter des traits agentiques tels que la compétitivité. Les individus ont tendance à afficher des comportements qui correspondent à leur genre en fonction des stéréotypes descriptifs prévalant dans leur culture et leur société. En fournissant des normes prescriptives sur la façon dont les hommes et les femmes devraient se comporter, la théorie de la congruence de genre suggère que les comportements sont récompensés lorsqu'ils sont conformes aux attentes liées aux stéréotypes sus-décrits. Les individus tendent à être plus efficaces et performants lorsqu'ils se comportent de manière conforme aux stéréotypes de genre, tandis que d'autres ont tendance à les évaluer plus généreusement lorsque les stéréotypes sont respectés. En adoptant cette perspective, j'étudie les mécanismes entraînés par les attentes stéréotypées par le genre dans les réseaux. Malgré l'accord entre les chercheurs sur les origines structurelles de l'inégalité entre les sexes, qui limitent la capacité des femmes à construire, mobiliser et bénéficier des réseaux sociaux en raison de leur statut inférieur présumé par rapport aux hommes, il y a encore peu de consensus sur les mécanismes qui produisent ces inégalités. Le focus de cette thèse porte sur l'impact que les stéréotypes de genre ont sur la formation de liens au sein de son réseau et des retours obtenus. Pour comprendre la source de l'écart de performance entre les sexes, j'adopte une perspective de réseau pour examiner en particulier si les différences découlent de la manière dont l'individu central se comporte ("processus ego") ou de la conduite des autres individus dans le réseau social ("comportements alter"). Cette approche permet de déterminer si les stéréotypes de genre ont un impact sur les actions de l'individu focal, qui à son tour affecte leurs résultats, si la réponse des autres envers un individu est influencée par leur genre, affectant leur performance, ou si les deux facteurs sont à l'oeuvre simultanément. La thèse se compose de trois essais, abordant chacun le sujet différemment, mais la question de recherche générale qui guide ce manuscrit est : Quels sont les biais dans les réseaux qui contribuent aux différences de genre dans la performance, spécifiquement dans l'innovation ? Et quels sont les mécanismes qui causent ces résultats inégaux ?Gender inequality in professional and organizational settings has been extensively researched from various perspectives. This dissertation aims to provide insights into the gender differences in social network dynamics by utilizing gender role expectations (Eagly, 1987; Eagly & Wood, 2012) as a theoretical framework. Furthermore, I examine the biased behaviors of both the focal actor and others that shape these dynamics… Gender stereotypes are a major societal factor contributing to gender differences. These stereotypes create specific expectations for men and women, influencing their behaviors and evaluations…By adopting this perspective, in this dissertation, I investigate some of the mechanisms driven by stereotyped gender role expectations and their influence on women’s performance through a specific mechanism: social networks… The focus of this dissertation is on the impact that gender stereotypes have on tie formation and network returns. To understand the source of the gender gap in career outcomes, I adopt the network lens to examine whether gender differences arise from how the focal individual behaves (referred to as “ego processes”) or from the conduct of other individuals in the social network (referred to as “alter behaviors”). This approach allows determining whether gender stereotypes impact the actions of the focal individual, which in turn affects their outcomes, whether the response of others towards an individual is influenced by their gender, affecting their performance, or if both factors are at play. The dissertation consists of three essays, each approaching the subject differently. In the first essay, I adopt a meta-analytic approach to investigate the sources of observed gender differences in self-selection into competitive ties.. In the second and third essays, I move to the investigation of network returns and explore what mechanisms explain differential benefits that men and women are able to reap from specific network characteristics…In the third essay, I take a structural perspective and investigate how connections to professional brokers can benefit women’s performance in entrepreneurship via an increased performance in the promotion phase of their idea…The overarching research question that drives my research is: What biases in social networks contribute to gender differences in performance, specifically innovation? And what are the mechanisms that result in unequal outcomes

Magma reservoirs and neutral buoyancy zones on Venus:implications for the formation and evolution of volcanic landforms

We examine the production of magma reservoirs and neutral buoyancy zones (NBZs) on Venus and the implications of their development for the formation and evolution of volcanic landforms. The high atmospheric pressure on Venus reduces volatile exsolution and generally serves to inhibit the formation of NBZs and shallow magma reservoirs. For a range of common terrestrial magma volatile contents, magma ascending and erupting near or below mean planetary radius (MPR) should not stall at shallow magma reservoirs; such eruptions would be characterized by relatively high total volumes and effusion rates. For the same range of volatile contents at 2 km above MPR, about half of the cases result in direct ascent of magma to the surface and half in the production of neutral buoyancy zones. In general, neutral buoyancy zones and shallow magma reservoirs begin to appear as gas content increases and are nominally shallower on Venus than on Earth. For a fixed volatile content, NBZs become deeper with increasing elevation: over the range of elevations treated here (−1 km to +4.4 km) depths differ by a factor of 2–4. These analyses reveal several factors that may help to account for the low height of volcanoes on Venus. Larger primary reservoirs cause the wide dispersal of conduits building edifices. Models of the position of the shallow NBZ reservoir during edifice growth show that for Earth the magma chamber center remains at a constant depth below the growing edifice summit, thus keeping pace with the increasing elevation, while on Venus the chamber center becomes deeper relative to the summit of the growing edifice because of the major change in atmospheric pressure as a function of altitude. Therefore neutral buoyancy zones and magma reservoirs on Venus will remain in the prevolcano substrate longer and in many cases may not emerge into the edifice at all; the lower rate of vertical migration implies that magma reservoirs would tend to stabilize, undergo greater lateral growth, and become larger on Venus than Earth. The proportion of the available magma going into production of the edifice relative to that intruded into the substrate is smaller on Venus than Earth. Large reservoirs would encourage multiple and more widely dispersed source vents and large volumes for individual eruptions. In large reservoirs, positively buoyant materials are likely to be produced from differentiation, substrate remelting, and volatile exsolution. Nonbuoyant materials exsolving volatiles in a shallow reservoir will need higher gas bubble concentrations to produce eruptions than on Earth, and when this gas-enriched melt emerges at the surface, it is more likely to retain its bubbles than to undergo explosive disruption due to the high surface atmospheric pressure. Therefore there is the potential for the production of a range of erupted lavas that have very high gas bubble concentrations, leading to anomalous, more viscous rheological properties. Inhibition of disruption of volatile-rich magma for both basaltic and more evolved compositions can lead to the production of (1) more bubble-rich, vesicular flows characterized by higher viscosity and greater thicknesses, the Venus equivalent of effusions that would have lost much of their volatiles in the fire-fountaining process on Earth (2), high-volume, high discharge rate extremely gas-rich basaltic effusions that increase viscosity considerably upon surface extrusion and produce domes whose volumes are considerably higher than their dense rock equivalent, and (3) more evolved compositions that are gas rich but do not undergo disruption upon effusion, and produce domes and flows of high viscosity, the Venus equivalent of terrestrial ignimbrites. On the basis of these analyses we predict that intrusions and dike emplacement should be common, particularly around both shallow and deep magma reservoirs, and the tops of dikes should be manifested as radial fractures. There should be a range of diameters of circular features associated with the presence of both shallow (NBZ-related) and deep (plumerelated) magma reservoirs. Large-volume lava outpourings should be favored at lower elevations, and shallow reservoirs and edifices should be more common at intermediate elevations; at the highest elevations, magma reservoirs are predicted to be large and relatively deep with low associated edifices. Direct ascent of magma where neutral buoyancy zones are unlikely (low elevations) and the propensity for relatively larger magma reservoirs on Venus when they do form, are both factors which will tend to favor high-volume eruptions, independent of variations in magma temperature or chemistry. Individual volcanic features should be interpreted in terms of regional geologic setting and the dynamics of elevation changes commonly associated with various scales of mantle processes and magma emplacement in order to assess global crustal growth processes on Venus

Near Full-Length Sequence Analysis of HIV Type 1 BF Recombinants from Italy

Abstract Recombination between HIV-1 subtypes B and F has generated several circulating and unique recombinant forms, particularly in Latin American areas. In Italy, subtype B is highly prevalent while subtype F is the most common pure non-B subtype. To investigate the recombination pattern in Italian BF recombinant viruses, we characterized full-length sequences derived from 15 adult patients, mostly Italian and infected by the heterosexual route. One of the BF mosaics was a CRF29, three sequences clustered with low bootstrap values with CRF39, CRF40, and CRF42. With the exception of the CRF29-like sequence, the other recombination patterns were unique, but two possible clusters were identified. Analysis of the gp120 V3 domain suggested a possible link with subtype F from Eastern Europe rather than from Latin America, favoring the hypothesis of local recombination between clade B and F viruses over that of import of BF recombinants from Latin America. HIV-1 subtypes B and F appear prone to generation of unique recombinants in Italy, warranting epidemiological surveillance and investigation of a possible clinical significance

Synthesis and biological evaluation of a library of hybrid derivatives as inhibitors of influenza virus PA-PB1 interaction

The limited treatment options against influenza virus along with the growing public health concerns regarding the continuous emergence of drug-resistant viruses make essential the development of new anti-flu agents with novel mechanisms of action. One of the most attractive targets is the interaction between two subunits of the RNA-dependent RNA polymerase, PA and PB1. Herein we report the rational design of hybrid compounds starting from a 3-cyano-4,6-diphenylpyridine scaffold recently identified as disruptor of PA-PB1 interactions. Guided by the previously reported SAR data, a library of amino acid derivatives was synthesized. The biological evaluation led to the identification of new PA-PB1 inhibitors, that do not show appreciable toxicity. Molecular modeling shed further lights on the inhibition mechanism of these compounds

An EEGManyLabs study to test the role of the alpha phase on visual perception (a replication and new evidence)

Several studies have suggested that low-frequency brain oscillations could be key to understanding how the brain samples sensory information via rhythmic alternation of low and high excitability periods. However, this hypothesis has recently been called into question following the publication of some null findings. As part of the #EEGManyLabs initiative, we set out to undertake a high-powered, multi-site replication of an influential study on this topic. In the original study, Mathewson et al. (2009) showed that during high amplitude fluctuations of alpha activity (8-13 Hz), the visibility of a visual target stimulus depended on the time the target was presented relative to the phase of the pre-target alpha activity. Furthermore, visual evoked potentials (e.g., N1, P1, P2 and P3) were larger in amplitude when the target was presented at the pre-stimulus alpha peaks, which were also associated with higher visibility. If we are successful in replicating the results of Mathewson et al. (2009), we intend to extend the original findings by conducting a second, original, experiment that varies the pre-stimulus time unpredictably to determine whether the phase-behavioural relationship depends on the target stimulus having a predictable onset time

An #EEGManyLabs study to test the role of the alpha phase on visual perception (a replication and new evidence)

Several studies have suggested that low-frequency brain oscillations could be key to understanding how the brain samples sensory information via rhythmic alternation of low and high excitability periods. However, this hypothesis has recently been called into question following the publication of some null findings. As part of the #EEGManyLabs initiative, we set out to undertake a high-powered, multi-site replication of an influential study on this topic. In the original study, Mathewson et al. (2009) showed that during high amplitude fluctuations of alpha activity (8-13 Hz), the visibility of a visual target stimulus depended on the time the target was presented relative to the phase of the pre-target alpha activity. Furthermore, visual evoked potentials (e.g., N1, P1, P2 and P3) were larger in amplitude when the target was presented at the pre-stimulus alpha peaks, which were also associated with higher visibility. If we are successful in replicating the results of Mathewson et al. (2009), we intend to extend the original findings by conducting a second, original, experiment that varies the pre-stimulus time unpredictably to determine whether the phase-behavioural relationship depends on the target stimulus having a predictable onset time