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Efficiently navigating a superpressure balloon in the stratosphere 1 requires the integration of a multitude of cues, such as wind speed and solar elevation, and the process is complicated by forecast errors and sparse wind measurements. Coupled with the need to make decisions in real time, these factors rule out the use of conventional control techniques 2 , 3 . Here we describe the use of reinforcement learning 4 , 5 to create a high-performing flight controller. Our algorithm uses data augmentation 6 , 7 and a self-correcting design to overcome the key technical challenge of reinforcement learning from imperfect data, which has proved to be a major obstacle to its application to physical systems 8 . We deployed our controller to station Loon superpressure balloons at multiple locations across the globe, including a 39-day controlled experiment over the Pacific Ocean. Analyses show that the controller outperforms Loon’s previous algorithm and is robust to the natural diversity in stratospheric winds. These results demonstrate that reinforcement learning is an effective solution to real-world autonomous control problems in which neither conventional methods nor human intervention suffice, offering clues about what may be needed to create artificially intelligent agents that continuously interact with real, dynamic environments. Data augmentation and a self-correcting design are used to develop a reinforcement-learning algorithm for the autonomous navigation of Loon superpressure balloons in challenging stratospheric weather conditions.

PurposeThe Elipse balloon is a novel, non-endoscopic option for weight loss. It is swallowed and filled with fluid. After 4 months, the balloon self-empties and is excreted naturally. Aim of the study was to evaluate safety and efficacy of Elipse balloon in a large, multicenter, population.Materials and MethodsData from 1770 consecutive Elipse balloon patients was analyzed. Data included weight loss, metabolic parameters, ease of placement, device performance, and complications.ResultsBaseline patient characteristics were mean age 38.8 ± 12, mean weight 94.6 ± 18.9 kg, and mean BMI 34.4 ± 5.3 kg/m2. Triglycerides were 145.1 ± 62.8 mg/dL, LDL cholesterol was 133.1 ± 48.1 mg/dL, and HbA1c was 5.1 ± 1.1%. Four-month results were WL 13.5 ± 5.8 kg, %EWL 67.0 ± 64.1, BMI reduction 4.9 ± 2.0, and %TBWL 14.2 ± 5.0. All metabolic parameters improved. 99.9% of patients were able to swallow the device with 35.9% requiring stylet assistance. Eleven (0.6%) empty balloons were vomited after residence. Fifty-two (2.9%) patients had intolerance requiring balloon removal. Eleven (0.6%) balloons deflated early. There were three small bowel obstructions requiring laparoscopic surgery. All three occurred in 2016 from an earlier design of the balloon. Four (0.02%) spontaneous hyperinflations occurred. There was one (0.06%) case each of esophagitis, pancreatitis, gastric dilation, gastric outlet obstruction, delayed intestinal balloon transit, and gastric perforation (repaired laparoscopically).ConclusionThe Elipse™ Balloon demonstrated an excellent safety profile. The balloon also exhibited remarkable efficacy with 14.2% TBWL and improvement across all metabolic parameters.

In just the past 5 years, the field of Earth observation has progressed beyond the offerings of conventional space-agency-based platforms to include a plethora of sensing opportunities afforded by CubeSats, unmanned aerial vehicles (UAVs), and smartphone technologies that are being embraced by both for-profit companies and individual researchers. Over the previous decades, space agency efforts have brought forth well-known and immensely useful satellites such as the Landsat series and the Gravity Research and Climate Experiment (GRACE) system, with costs typically of the order of 1 billion dollars per satellite and with concept-to-launch timelines of the order of 2 decades (for new missions). More recently, the proliferation of smartphones has helped to miniaturize sensors and energy requirements, facilitating advances in the use of CubeSats that can be launched by the dozens, while providing ultra-high (3–5 m) resolution sensing of the Earth on a daily basis. Start-up companies that did not exist a decade ago now operate more satellites in orbit than any space agency, and at costs that are a mere fraction of traditional satellite missions. With these advances come new space-borne measurements, such as real-time high-definition video for tracking air pollution, storm-cell development, flood propagation, precipitation monitoring, or even for constructing digital surfaces using structure-from-motion techniques. Closer to the surface, measurements from small unmanned drones and tethered balloons have mapped snow depths, floods, and estimated evaporation at sub-metre resolutions, pushing back on spatio-temporal constraints and delivering new process insights. At ground level, precipitation has been measured using signal attenuation between antennae mounted on cell phone towers, while the proliferation of mobile devices has enabled citizen scientists to catalogue photos of environmental conditions, estimate daily average temperatures from battery state, and sense other hydrologically important variables such as channel depths using commercially available wireless devices. Global internet access is being pursued via high-altitude balloons, solar planes, and hundreds of planned satellite launches, providing a means to exploit the internet of things as an entirely new measurement domain. Such global access will enable real-time collection of data from billions of smartphones or from remote research platforms. This future will produce petabytes of data that can only be accessed via cloud storage and will require new analytical approaches to interpret. The extent to which today's hydrologic models can usefully ingest such massive data volumes is unclear. Nor is it clear whether this deluge of data will be usefully exploited, either because the measurements are superfluous, inconsistent, not accurate enough, or simply because we lack the capacity to process and analyse them. What is apparent is that the tools and techniques afforded by this array of novel and game-changing sensing platforms present our community with a unique opportunity to develop new insights that advance fundamental aspects of the hydrological sciences. To accomplish this will require more than just an application of the technology: in some cases, it will demand a radical rethink on how we utilize and exploit these new observing systems.

Barometers floating on high‐altitude balloons in the relatively clement cloud layer on Venus could detect and characterize acoustic waves generated by seismic activity, avoiding the need for high‐temperature electronics required for surface seismology. Garcia et al. (2022, https://doi.org/10.1029/2022GL098844) recently demonstrated the detection of low‐frequency sound (infrasound) caused by earthquakes of magnitudes 7.3 and 7.5 from stratospheric balloons nearly 3,000 km away from the epicenter. They provided a preliminary demonstration of earthquake magnitude and location inversion, and the determination of S‐ and Rayleigh wave velocities using only their acoustic signature. Large earthquakes produce low‐frequency seismic waves that penetrate the interiors of planets; their detection at continental‐scale distances from a high‐vantage point demonstrates the feasibility of balloon‐based investigations of Venus' interior. We contextualize these results within the effort to perform seismology on Venus from balloons, discuss its limitations, and share perspectives on open research questions in this area. Plain Language Summary Scientists have peered inside Earth, the Moon, and Mars by recording how seismic waves pass through them. Venus' interior is a mystery, though, because the heat and pressure at its surface have thus far prevented direct measurement of seismic activity. Balloons with pressure recorders higher up in the Venusian atmosphere, where it is much cooler, can listen for the sounds the seismic waves make as a proxy for directly measuring ground motion. Before sending the balloons to Venus, it is important to make sure that this idea would actually work. The fact that (Garcia et al., 2022, https://doi.org/10.1029/2022GL098844) were able to record sound from large earthquakes thousands of kilometers away on Earth means that one should be able to do the same thing on Venus as well. While there are still details to work out, listening for quakes on Venus from balloons just got a major boost here on Earth. Key Points A network of stratospheric balloons captured infrasound from several large earthquakes This is the first detection of seismic activity from airborne sensors at continental distances A similar network on Venus could capture and geolocate seismic activity

During the 2022/23 Antarctic summer, eight pico balloon flights were deployed from Neumayer Station III (70.6666°S, 8.2667°W), yielding valuable insights into the Antarctic stratospheric wind structure. Pico balloons maintain a lower altitude compared to larger superpressure balloons, floating between 9 and 15 km MSL. The most impressive flight lasted an astounding 98 days, completing eight circumnavigations of the Southern Hemisphere. Throughout the flights, pico balloons encountered diverse air masses, displaying zonal velocities ranging from −50 to 250 km h −1 and meridional velocities between ±100 km h −1 . Total wind speeds observed were extensive, spanning from 2.0 to 270 km h −1 . A significant finding revealed that lower-flying pico balloons could rise due to convection underneath the flight paths, influenced by high convective available potential energy environments, resulting in changes to the balloons’ float density. Moreover, the flights demonstrated that pico balloons tended to drift farther south compared to larger stratospheric balloons, with some balloons reaching up to 8° south of the equator and 2° from the South Pole. This article explores the pressure-testing process and deployment techniques for pico balloons, showcasing their transformation from inexpensive party balloons (costing less than $20) into efficient superpressure balloons. The logistical demands for pico balloon flights were minimal, with a single person transporting all materials for the balloons (excluding lifting gas) to the Antarctic continent in carry-on luggage. The authors aim to promote the application of pico balloons to a wider scientific community by demonstrating their usefulness.

Tropical tropopause layer (TTL) cirrus clouds play a key role in the Earth climate system. Yet the relative role of the various processes shaping them remains poorly known. Characterizing the temporal evolution of cloudy structures from observations is essential to address this issue but represents a challenge. Indeed, space‐ and airborne platforms move fast and mainly provide instantaneous snapshots. In boreal winter 2021–2022, two balloon‐borne lidars flew over the Equatorial Pacific Ocean, slowly drifting above the clouds. We use those unique nighttime observations to quantify the distribution of TTL cloud lifetime above this homogeneous region. This distribution is strongly asymmetric: half of the clouds live less than 1 hr, but their mean lifetime is about 6 hr. The few long‐lived clouds (>12 ${ >} 12$ hr) dominate the cloud cover. Those results compare reasonably well with TTL cirrus lifetimes in the ERA5 reanalysis, although the modeled TTL cloud cover is largely underestimated.

In-stent restenosis (ISR) accounts for 10% of percutaneous coronary intervention (PCI) in the United States. Paclitaxel-coated balloons (PCBs) have been evaluated as a therapy for coronary ISR in multiple randomized controlled trials (RCTs). We searched PubMed/MEDLINE, Cochrane Library, and ClinicalTrials.gov (from inception to April 1, 2024) for RCTs evaluating PCBs versus uncoated balloon angioplasty (BA) in patients with coronary ISR. The outcomes of interest were target lesion revascularization (TLR), major adverse cardiovascular events (MACEs), all-cause mortality, cardiovascular mortality, myocardial infarction (MI), and stent thrombosis. We pooled the estimates using an inverse variance random-effects model. The effect sizes were reported as risk ratio (RR) with 95% confidence interval (CI). A total of 6 RCTs with 1,343 patients were included. At a follow-up ranging from 6 to 12 months from randomization, the use of PCBs was associated with a statistically significant decrease in TLR (RR 0.28, 95% CI 0.11 to 0.68) and MACE (RR 0.35, 95% CI 0.20 to 0.64) compared with BA for coronary ISR. However, there was no significant difference in risk between PCBs and BA in terms of all-cause mortality (RR 0.56, 95% CI 0.14 to 2.31), cardiovascular mortality (RR 0.61, 95% CI 0.02 to 16.85), MI (RR 0.60, 95% CI 0.27 to 1.31), and stent thrombosis (RR 0.13, 95% CI 0.00 to 5.06). In conclusion, this meta-analysis suggests that PCBs compared with uncoated BA for the treatment of coronary ISR at intermediate-term follow-up of 1 year were associated with a significant decrease in TLR and MACE without any difference in mortality, MI, or stent thrombosis.

Commercial providers open the market for new types of research flight.

Commercial providers open the market for new types of research flight.

Commercial providers open the market for new types of research flight.