Simple signaling games of sexual selection (Grafen’s revisited)

International audienceWe investigate several versions of a simple game of sexual selection, to explore the role of secondary sexual characters (the "handicap paradox") with the tools of signaling theory. Our models admit closed form solutions. They are very much inspired by Grafen's (J Theor Biol 144:517-546, 1990a; J Theor Biol 144:473-516, 1990b) seminal companion papers. By merging and simplifying his two approaches, we identify a not so minor artifact in the seminal study. We propose an alternative model to start with Grafen's sexual selection theory, with several similarities with Getty (Anim Behav 56:127-130, 1998)

Uncoupling Isaacs’equations in nonzero-sum two-player differential games : The example of conflict over parental care

International audienceWe use a recently uncovered decoupling of Isaacs PDE’s of some mixed closed loop Nash equilibria to give a rather complete analysis of the classical problem of conflict over parental care in behavioural ecology, for a more general set up than had been considered heretofore.On utilise un découplage récemment mis en évidence des équations d’Isaacs d’un jeu différentiel pour des stratégies mixtes singulières particulières pour donner une analyse assez complète d’un problème classique en écologie comportementale concernant le conflit à propos des soins parentaux

Influence of intensive agriculture and geological heterogeneity on the recharge of an arid aquifer system (Saq–Ram, Arabian Peninsula) inferred from GRACE data

This study assesses the detailed water budget of the Saq–Ram Aquifer System (520 000 km2) over the 2002–2019 period using satellite gravity data from the Gravity Recovery And Climate Experiment (GRACE). The three existing GRACE solutions were tested for their local compatibility to compute groundwater storage (GWS) variations in combination with the three soil moisture datasets available from the land surface models (LSMs) of the Global Land Data Assimilation System (GLDAS). Accounting for groundwater pumping, artificial recharge, and natural discharge uniformly distributed over the Saq–Ram domain, the GRACE-derived mass balance calculation for water yields a long-term estimate of the domain-averaged natural recharge of (2.4±1.4) mm yr−1, corresponding to (4.4±2.6) % of the annual average rainfall (AAR). Beyond the regional-scale approach proposed here, spatial heterogeneities regarding the groundwater recharge were identified. The first source of heterogeneity is of anthropogenic origin: chiefly induced by irrigation excess over irrigated surfaces (about 1 % of the domain), artificial recharge corresponds to half of the total recharge of the aquifer. The second source of recharge heterogeneity identified here is natural: volcanic lava deposits (called harrats on the Arabian Peninsula) which cover 8 % of the Saq–Ram aquifer domain but contribute to more than 50 % of the natural recharge. Hence, in addition to this application on the Arabian Peninsula, this study strongly indicates a major control of geological context on arid aquifer recharge, which has been poorly discussed hitherto. Due to large lag times of the diffuse recharge mechanism, the annual analysis using this GRACE–GLDAS approach in arid domains should be limited to areas where focused recharge is the main mechanism, while long-term analysis is valid regardless of the recharge mechanism. Moreover, it appears that about 15 years of GRACE records are required to obtain a relevant long-term recharge estimate.</p

The breastfeeding experience of women with major difficulties who use the services of a breastfeeding clinic: a descriptive study

<p>Abstract</p> <p>Background</p> <p>Many women experience breastfeeding difficulties. Sometimes these difficulties lead to breastfeeding cessation. Breastfeeding clinics provide support for women facing such problems. This study aims to describe the breastfeeding experience of women, particularly those who use the services of the breastfeeding clinic located in the Greater Quebec City area.</p> <p>Methods</p> <p>This is a descriptive study based on information gathered through telephone questionnaires that were administered in 2006 to a sample of 86 women and semi-structured interviews conducted with 12 of these women.</p> <p>Results</p> <p>Painful nipples/breasts, low milk supply and latching difficulties were the three most frequent major breastfeeding problems identified by women. Their personal characteristics as well as the moral and physical support provided by family and friends and by health professional and clinicians at the breastfeeding clinic were the factors identified most often as having a positive influence on the breastfeeding experience.</p> <p>Conclusion</p> <p>The results suggest that breastfeeding clinics have a critical role to play in improving the breastfeeding experience of women with major difficulties.</p