Precision and scaling in morphogen gradient read-out

Morphogen gradients infer cell fate as a function of cellular position. Experiments in Drosophila embryos have shown that the Bicoid (Bcd) gradient is precise and exhibits some degree of scaling. We present experimental results on the precision of Bcd target genes for embryos with a single, double or quadruple dose of bicoid demonstrating that precision is highest at mid-embryo and position dependent, rather than gene dependent. This confirms that the major contribution to precision is achieved already at the Bcd gradient formation. Modeling this dynamic process, we investigate precision for inter-embryo fluctuations in different parameters affecting gradient formation. Within our modeling framework, the observed precision can only be achieved by a transient Bcd profile. Studying different extensions of our modeling framework reveals that scaling is generally position dependent and decreases toward the posterior pole. Our measurements confirm this trend, indicating almost perfect scaling except for anterior most expression domains, which overcompensate fluctuations in embryo length

Uncovering the topology of configuration space networks

The configuration space network (CSN) of a dynamical system is an effective approach to represent the ensemble of configurations sampled during a simulation and their dynamic connectivity. To elucidate the connection between the CSN topology and the underlying free-energy landscape governing the system dynamics and thermodynamics, an analytical soluti on is provided to explain the heavy tail of the degree distribution, neighbor co nnectivity and clustering coefficient. This derivation allows to understand the universal CSN network topology observed in systems ranging from a simple quadratic well to the native state of the beta3s peptide and a 2D lattice heteropolymer. Moreover CSN are shown to fall in the general class of complex networks describe d by the fitness model.Comment: 6 figure

Oversexualisation, romantic attachment, and intimacy

Abstract : The present study examined romantic attachment and intimacy as correlates of oversexualized behaviours and attitudes among emerging adults. A sample of 587 participants (494 women, 93 men) aged between 18 and 29 completed a series of online questionnaires assessing oversexualisation, romantic attachment, and intimacy. Hierarchical regression analyses were performed to explore the associations between these variables and examine the moderating role of sex. Results revealed that attachment-related anxiety was associated with overinvestment in sexual appearance, sexual objectification, and performance-based sexuality. This last association was stronger for men than for women. Attachment-related avoidance was associated with seduction and lower meaningfulness of sexuality. In addition, while sexualized language was related to a better perception of emotional, social, sexual, and recreational intimacy, meaningfulness of sexuality was positively related to all dimensions of intimacy. Conversely, sexual objectification was related to lower recreational intimacy, seductive attitude was related to lower emotional intimacy, and overinvestment in one’s sexualized appearance was related to lower sexual intimacy. For men only, overinvestment in sexualized appearance was also related to higher perceived social intimacy Theoretical and clinical implications of these results are discussed