1,630 research outputs found
The sexually antagonistic genes of Drosophila melanogaster
When selective pressures differ between males and females, the genes experiencing these conflicting evolutionary forces are said to be sexually antagonistic. Although the phenotypic effect of these genes has been documented in both wild and laboratory populations, their identity, number, and location remains unknown. Here, by combining data on sex-specific fitness and genome-wide transcript abundance in a quantitative genetic framework, we identified a group of candidate genes experiencing sexually antagonistic selection in the adult, which correspond to 8% of Drosophila melanogaster genes. As predicted, the X chromosome is enriched for these genes, but surprisingly they represent only a small proportion of the total number of sex-biased transcripts, indicating that the latter is a poor predictor of sexual antagonism. Furthermore, the majority of genes whose expression profiles showed a significant relationship with either male or female adult fitness are also sexually antagonistic. These results provide a first insight into the genetic basis of intralocus sexual conflict and indicate that genetic variation for fitness is dominated and maintained by sexual antagonism, potentially neutralizing any indirect genetic benefits of sexual selection
A Novel Dissipativity-Based Control for Inexact Nonlinearity Cancellation Problems
When dealing with linear systems feedback interconnected with memoryless nonlinearities, a natural control strategy is making the overall dynamics linear at first and then designing a linear controller for the remaining linear dynamics. By canceling the original nonlinearity via a first feedback loop, global linearization can be achieved. However, when the controller is not capable of exactly canceling the nonlinearity, such control strategy may provide unsatisfactory performance or even induce instability. Here, the interplay between accuracy of nonlinearity approximation, quality of state estimation, and robustness of linear controller is investigated and explicit conditions for stability are derived. An alternative controller design based on such conditions is proposed and its effectiveness is compared with standard methods on a benchmark system
What is known from the existing literature about the available interventions for pelvic floor dysfunction among female athletes? A scoping review
Background: Female athletes may be at higher risk of developing pelvic floor dysfunction (PFD). However, despite the great number of epidemiologic studies, the interventions have not been standardized. Aim: The present scoping review aimed to map and summarize the literature to identify the available interventions for PFD among female athletes. Methods: Seven databases were searched up to May 2021. Studies considering female athletes practising sports at any performance level with any type of PFD were eligible for inclusion. Any clinical intervention and any context were considered. No language, study design, and publication type restrictions were applied. Additional studies were identified through gray literature and the reference lists of articles included. The results were presented numerically and thematically. Results: From 2625 initial records, 35 studies met inclusion criteria. The majority of articles were narrative reviews, considering athletes with urinary incontinence practising multiple or high-impact sports. Authors discussed a wide range of interventions: preventive (n = 8); conservative (n = 35), pharmacological (n = 12), and surgical (n = 10). In particular, the Pelvic Floor Muscle Training was considered in 30 studies. Conclusions: This is the first scoping review to provide a comprehensive overview of the topic. Besides the great number of available interventions, specific programs and randomized controlled clinical trials for female athletes are still limited. Findings highlighted evident gaps in the primary research confirming that the current management is based on expert opinion. This review may be useful for the overall management, and it may represent a starting point for future research
Training Program at Medical School of Chieti, Italy
We describe the changes in medical training program offered at the G. D’Annunzio University Medical School in Chieti-Pescara, Italy, which took place over the last decade. The new curriculum differs from the previous one in several important aspects, including limited number of students admitted to school depending on the estimated needs for physicians, obligatory class attendance, student attendance in preclinical laboratories, formative credits as a measure of student activity, and elective subjects. Furthermore, all medical graduates are allowed to take the State exam to obtain the license to practice, which was not the case previously. As a result of these major changes, a higher number of students graduates in due time. The changes made in the medical education curriculum in Italy have enabled Italian medical graduates to work in European Community Hospitals, because their medical degree is recognized in other EU countries. The main motif that drives the Medical School in Chieti-Pescara is the achievement of high quality in medical education and biomedical research by creating as strong a relationship between education and research as possible
Mechanisms through which Sos-1 coordinates the activation of Ras and Rac
Signaling from receptor tyrosine kinases (RTKs)* requires the sequential activation of the small GTPases Ras and Rac. Son of sevenless (Sos-1), a bifunctional guanine nucleotide exchange factor (GEF), activates Ras in vivo and displays Rac-GEF activity in vitro, when engaged in a tricomplex with Eps8 and E3b1–Abi-1, a RTK substrate and an adaptor protein, respectively. A mechanistic understanding of how Sos-1 coordinates Ras and Rac activity is, however, still missing. Here, we demonstrate that (a) Sos-1, E3b1, and Eps8 assemble into a tricomplex in vivo under physiological conditions; (b) Grb2 and E3b1 bind through their SH3 domains to the same binding site on Sos-1, thus determining the formation of either a Sos-1–Grb2 (S/G) or a Sos-1–E3b1–Eps8 (S/E/E8) complex, endowed with Ras- and Rac-specific GEF activities, respectively; (c) the Sos-1–Grb2 complex is disrupted upon RTKs activation, whereas the S/E/E8 complex is not; and (d) in keeping with the previous result, the activation of Ras by growth factors is short-lived, whereas the activation of Rac is sustained. Thus, the involvement of Sos-1 at two distinct and differentially regulated steps of the signaling cascade allows for coordinated activation of Ras and Rac and different duration of their signaling within the cell
Simulation of Calcium Phosphate Pre-Nucleation Clusters in Aqueous Solution: Association Beyond Ion Pairing
© 2019 American Chemical Society. Classical molecular dynamics simulations and free energy methods have been used to obtain a better understanding of the molecular processes occurring prior to the first nucleation event for calcium phosphate biominerals. The association constants for the formation of negatively charged complexes containing calcium and phosphate ions in aqueous solution have been computed, and these results suggest that the previously proposed calcium phosphate building unit, [Ca(HPO4)3]4-, should only be present in small amounts under normal experimental conditions. However, the presence of an activation barrier for the removal of an HPO42- ion from this complex indicates that this species could be kinetically trapped. Aggregation pathways involving CaHPO4, [Ca(HPO4)2]2-, and [Ca(HPO4)3]4- complexes have been explored with the finding that dimerization is favorable up to a Ca/HPO4 ratio of 1:2
- …