University of Lorraine

About: University of Lorraine is a education organization based out in Nancy, France. It is known for research contribution in the topics: Population & Context (language use). The organization has 11942 authors who have published 25010 publications receiving 425227 citations. The organization is also known as: Lorraine University.

Systematic review: fertility in non-surgically treated inflammatory bowel disease

Abstract: Summary Background Inflammatory bowel diseases (IBD) typically affect young patients during the reproductive years, and reproductive issues are of key concern to them. Aim To evaluate the impact of IBD on fertility in both women and men with IBD who had no history of surgical treatment for IBD. Methods We searched MEDLINE, Cochrane Library, EMBASE and international conference abstracts and included all controlled observational studies that evaluated fertility in Crohn's disease (CD) and/or ulcerative colitis (UC) in women and/or men. Results Eleven studies matching our criteria were included. In women with CD, there was a 17–44% reduction in fertility as compared with controls. Reduction in fertility was linked to voluntary childlessness, while there was no evidence of physiological causes of infertility. Most studies did not find any reduction in fertility in women with UC as compared with controls. In men with CD, there was an 18–50% reduction in fertility as compared with controls with no difference in reproductive capacity. There was no evidence of reduced fertility in men with UC. Conclusions The infertility observed in both women and men with CD is due to voluntary childlessness as opposed to involuntary infertility. This voluntary childlessness is often based on incorrect beliefs about the impact of the disease on fertility and pregnancy outcomes. Our results reinforce the need to increase awareness among male and female patients that IBD does not itself lead to reduced fertility.

A Survey on Policy Search Algorithms for Learning Robot Controllers in a Handful of Trials

Abstract: Most policy search (PS) algorithms require thousands of training episodes to find an effective policy, which is often infeasible with a physical robot. This survey article focuses on the extreme other end of the spectrum: how can a robot adapt with only a handful of trials (a dozen) and a few minutes? By analogy with the word “big-data,” we refer to this challenge as “micro-data reinforcement learning.” In this article, we show that a first strategy is to leverage prior knowledge on the policy structure (e.g., dynamic movement primitives), on the policy parameters (e.g., demonstrations), or on the dynamics (e.g., simulators). A second strategy is to create data-driven surrogate models of the expected reward (e.g., Bayesian optimization) or the dynamical model (e.g., model-based PS), so that the policy optimizer queries the model instead of the real system. Overall, all successful micro-data algorithms combine these two strategies by varying the kind of model and prior knowledge. The current scientific challenges essentially revolve around scaling up to complex robots, designing generic priors, and optimizing the computing time.

Argon isotopic composition of Archaean atmosphere probes early Earth geodynamics

Abstract: Understanding the growth rate of the continental crust through time is a fundamental issue in Earth sciences1–8.The isotopic signatures of noble gases in the silicate Earth (mantle, crust) and in the atmosphere afford exceptional insight into the evolution through time of these geochemical reservoirs9. However, no data for the compositions of these reservoirs exists for the distant past, and temporal exchange rates between Earth’s interior and its surface are severely under-constrainedowing to a lack of samples preserving the original signature of the atmosphere at the time of their formation. Here, we report the analysis of argon in Archaean (3.5-billion-year-old) hydrothermal quartz. Noble gases are hosted in primary fluid inclusions containing a mixture of Archaean freshwater and hydrothermal fluid. Our analysis reveals Archaean atmospheric argon with a 40Ar/36Ar value of 143624, lower than the present-day value of 298.6 (for which 40Ar has been produced by the radioactive decay of the potassium isotope 40K, with a half-life of 1.25 billion years; 36Ar is primordial in origin). This ratio is consistent with an early development of the felsic crust, which might have had an important role in climate variability during the first half of Earth’s history.