Characterization of the Immune Response To Anti-mullerian Hormone

Anti-Mullerian hormone (AMH) has been known since the mid-twentieth century as the substance secreted by the testes of the male fetus that is responsible for directing the proper development of the male reproductive organs from the primordial structures that would otherwise become the uterus and fallopian tubes. However, despite its longknown significance in male development, only recently has its importance in the adult female become evident. AMH is now considered to be not only a clinical indicator of the finite ovarian egg supply, but a vital regulator thereof throughout the reproductive life of the female. Dysfunctions in AMH regulation may lead to infertility that underlies conditions such as primary ovarian insufficiency (POI) and polycystic ovarian syndrome (PCOS). Moreover, mounting clinical and experimental evidence suggests that many such cases may be the result of autoimmunity to AMH. To test this hypothesis, an animal model of AMH autoimmunity was developed by immunization of C57BL/6J female mice with recombinant AMH protein. These mice developed a typical autoimmune profile with a robust antigen-specific type-1/type-17 immune response with high frequencies of CD4+ T cells that transiently infiltrated ovarian tissues as well as long-lasting high titers of IgG1 and IgG2b in the serum. Most importantly, the mice exhibited a unique and previously unreported phenotype in which their reproductive lifespan was extended. Mice immunized with AMH in complete Freund\u27s adjuvant (CFA) remained fertile at ten months of age at a time when control mice immunized with CFA alone exhibited a viii natural decline in fertility due to reproductive senescence. AMH-immunized mice had more litters, greater numbers of pups per litter, and conserved more active follicles than controls at ten months. This effect correlated with a significant lengthening of the estrous cycle, resulting in fewer cycles over time which did not reduce the probability of conception or the health and viability of the offspring, but rather extended the fertile lifespan of the mice. This novel model of experimental autoimmune oophoritis (EAO) helps advance the knowledge of the physiologic role of AMH in the female, and may aid in understanding and managing human health conditions such as menopause and infertility

Giant Planet Occurrence in the Stellar Mass-Metallicity Plane

Correlations between stellar properties and the occurrence rate of exoplanets can be used to inform the target selection of future planet search efforts and provide valuable clues about the planet formation process. We analyze a sample of 1194 stars drawn from the California Planet Survey targets to determine the empirical functional form describing the likelihood of a star harboring a giant planet as a function of its mass and metallicity. Our stellar sample ranges from M dwarfs with masses as low as 0.2 Msun to intermediate-mass subgiants with masses as high as 1.9 Msun. In agreement with previous studies, our sample exhibits a planet-metallicity correlation at all stellar masses; the fraction of stars that harbor giant planets scales as f \propto 10^{1.2 [Fe/H]}. We can rule out a flat metallicity relationship among our evolved stars (at 98% confidence), which argues that the high metallicities of stars with planets are not likely due to convective envelope "pollution." Our data also rule out a constant planet occurrence rate for [Fe/H]< 0, indicating that giant planets continue to become rarer at sub-Solar metallicities. We also find that planet occurrence increases with stellar mass (f \propto Mstar), characterized by a rise from 3.5% around M dwarfs (0.5 Msun) to 14% around A stars (2 Msun), at Solar metallicity. We argue that the correlation between stellar properties and giant planet occurrence is strong supporting evidence of the core accretion model of planet formation.Comment: Fixed minor typos, modified the last paragraph of Section

Spatially Resolved Images of Dust Belt(s) Around the Planet-hosting Subgiant Kappa CrB

We present Herschel spatially resolved images of the debris disc orbiting the subgiant Kappa CrB. Not only are these the first resolved images of a debris disc orbiting a subgiant, but Kappa CrB is a rare example of an intermediate mass star where a detailed study of the structure of the planetary system can be made, including both planets and planetesimal belt(s). The only way to discover planets around such stars using the radial velocity technique is to observe 'retired' A stars, which are cooler and slower rotators compared to their main-sequence counterparts. A planetary companion has already been detected orbiting the subgiant Kappa CrB, with revised parameters of m sin i = 2.1MJ and apl = 2.8AU (Johnson et al. 2008a). We present additional Keck I HIRES radial velocity measurements that provide evidence for a second planetary companion, alongside Keck II AO imaging that places an upper limit on the mass of this companion. Modelling of our Herschel images shows that the dust is broadly distributed, but cannot distinguish between a single wide belt (from 20 to 220AU) or two narrow dust belts (at around 40 and 165AU). Given the existence of a second planetary companion beyond approximately 3AU it is possible that the absence of dust within approximately 20AU is caused by dynamical depletion, although the observations are not inconsistent with depletion of these regions by collisional erosion, which occurs at higher rates closer to the star.Comment: Updated abstrac

Proprioception and Tail Control Enable Extreme Terrain Traversal by Quadruped Robots

Legged robots leverage ground contacts and the reaction forces they provide to achieve agile locomotion. However, uncertainty coupled with contact discontinuities can lead to failure, especially in real-world environments with unexpected height variations such as rocky hills or curbs. To enable dynamic traversal of extreme terrain, this work introduces 1) a proprioception-based gait planner for estimating unknown hybrid events due to elevation changes and responding by modifying contact schedules and planned footholds online, and 2) a two-degree-of-freedom tail for improving contact-independent control and a corresponding decoupled control scheme for better versatility and efficiency. Simulation results show that the gait planner significantly improves stability under unforeseen terrain height changes compared to methods that assume fixed contact schedules and footholds. Further, tests have shown that the tail is particularly effective at maintaining stability when encountering a terrain change with an initial angular disturbance. The results show that these approaches work synergistically to stabilize locomotion with elevation changes up to 1.5 times the leg length and tilted initial states.Comment: 8 pages, 9 figures, accepted to IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 202

The Simplest Walking Robot: A bipedal robot with one actuator and two rigid bodies

We present the design and experimental results of the first 1-DOF, hip-actuated bipedal robot. While passive dynamic walking is simple by nature, many existing bipeds inspired by this form of walking are complex in control, mechanical design, or both. Our design using only two rigid bodies connected by a single motor aims to enable exploration of walking at smaller sizes where more complex designs cannot be constructed. The walker, "Mugatu", is self-contained and autonomous, open-loop stable over a range of input parameters, able to stop and start from standing, and able to control its heading left and right. We analyze the mechanical design and distill down a set of design rules that enable these behaviors. Experimental evaluations measure speed, energy consumption, and steering

Proprioception and reaction for walking among entanglements

Entanglements like vines and branches in natural settings or cords and pipes in human spaces prevent mobile robots from accessing many environments. Legged robots should be effective in these settings, and more so than wheeled or tracked platforms, but naive controllers quickly become entangled and stuck. In this paper we present a method for proprioception aimed specifically at the task of sensing entanglements of a robot's legs as well as a reaction strategy to disentangle legs during their swing phase as they advance to their next foothold. We demonstrate our proprioception and reaction strategy enables traversal of entanglements of many stiffnesses and geometries succeeding in 14 out of 16 trials in laboratory tests, as well as a natural outdoor environment.Comment: Submitted to 2023 IEEE/RSJ International Conference on Intelligent Robots and System