The Invisible Majority? Evolution and Detection of Outer Planetary Systems without Gas Giants

We present 230 realizations of a numerical model of planet formation in systems without gas giants. These represent a scenario in which protoplanets grow in a region of a circumstellar disk where water ice condenses (the "ice line''), but fail to accrete massive gas envelopes before the gaseous disk is dispersed. Each simulation consists of a small number of gravitationally interacting oligarchs and a much larger number of small bodies that represent the natal disk of planetesimals. We investigate systems with varying initial number of oligarchs, oligarch spacing, location of the ice line, total mass in the ice line, and oligarch mean density. Systems become chaotic in ~1 Myr but settle into stable configurations in 10-100 Myr. We find: (1) runs consistently produce a 5-9 Earth mass planet at a semimajor axis of 0.25-0.6 times the position of the ice line, (2) the distribution of planets' orbital eccentricities is distinct from, and skewed toward lower values than the observed distribution of (giant) exoplanet orbits, (3) inner systems of two dominant planets (e.g., Earth and Venus) are not stable or do not form because of the gravitational influence of the innermost icy planet. The planets predicted by our model are unlikely to be detected by current Doppler observations. Microlensing is currently sensitive to the most massive planets found in our simulations. A scenario where up to 60% of stars host systems such as those we simulate is consistent with all the available data. We predict that, if this scenario holds, the NASA Kepler spacecraft will detect about 120 planets by two or more transits over the course of its 3.5 yr mission. Future microlensing surveys will detect ~130 analogs over a 5 yr survey. Finally, the Space Interferometry Mission (SIM-Lite) should be capable of detecting 96% of the innermost icy planets over the course of a 5 yr mission.Comment: 17 pages, 16 figure

Machines Like Me: A Proposal on the Admissibility of Artificially Intelligent Expert Testimony

With the rapidly expanding sophistication of artificial intelligence systems, their reliability, and cost-effectiveness for solving problems, the current trend of admitting testimony based on artificially intelligent (AI) systems is only likely to grow. In that context, it is imperative for us to ask what rules of evidence judges today should use relating to such evidence. To answer that question, we provide an in-depth review of expert systems, machine learning systems, and neural networks. Based on that analysis, we contend that evidence from only certain types of AI systems meet the requirements for admissibility, while other systems do not. The break in admissible/inadmissible AI evidence is a function of the opaqueness of the underlying computational methodology of the AI system and the court’s ability to assess that methodology. The admission of AI evidence also requires us to navigate pitfalls including the difficulty of explaining AI systems’ methodology and issues as to the right to confront witnesses. Based on our analysis, we offer several policy proposals that would address weaknesses or lack of clarity in the current system. First, in light of the long-standing concern that jurors would allow expertise to overcome their own assessment of the evidence and blindly agree with the “infallible” result of advanced-computing AI, we propose that jury instruction commissions, judicial panels, circuits, or other parties who draft instructions consider adopting a cautionary instruction for AI-based evidence. Such an instruction should remind jurors that the AI-based evidence is solely one part of the analysis, the opinions so generated are only as good as the underlying analytical methodology, and ultimately, the decision to accept or reject the evidence, in whole or in part, should remain with the jury alone. Second, as we have concluded that the admission of AI-based evidence depends largely on the computational methodology underlying the analysis, we propose for AI evidence to be admissible, the underlying methodology must be transparent because the judicial assessment of AI technology relies on the ability to understand how it functions

Selling just preservation

Treves et al. argue for better representation of voiceless groups in current policy decisions. We agree with the argument but believe it will be challenging to convince enough people of its importance to change policy — especially those political groups who are not predisposed to agreeing with these kinds of arguments. We draw on the social psychology literature to recommend three principles for increasing the persuasiveness of the argument to the public: pre-suasion, framing, and tailoring for the audience. We apply these principles to make concrete recommendations for framing the argument to persuade the American political right

Analysis of Clostridium difficile patterns at Thomas Jefferson University Hospital

AIMS: To analyze CDI patterns to TJUH, particularly in Opportunity Units To visually examine the relationship between CDI cases within units Provide data analysis to the CDI working grouphttps://jdc.jefferson.edu/patientsafetyposters/1072/thumbnail.jp

“A small leak will sink a great ship”: hypoxia-inducible factor and group III pulmonary hypertension

Pulmonary hypertension complicating idiopathic pulmonary fibrosis, also known as secondary pulmonary hypertension, represents a major source of morbidity and mortality in affected patients. While the study of primary pulmonary arterial hypertension has yielded several therapies, the same is not true for the treatment of pulmonary hypertension secondary to pulmonary fibrosis. Recent studies have indicated an important role of hypoxia-inducible factor (HIF) – a regulatory protein that is vital in adaptation to hypoxic conditions – in the development of secondary pulmonary hypertension. HIF influences development of hypoxia-induced pulmonary hypertension through alteration in voltage-gated potassium channels and homeostatic calcium regulation, resulting in disruption of endothelial cell-cell communication, and eventual vascular remodeling. This article summarizes salient literature related to HIF and secondary pulmonary hypertension, in addition to proposing a final common pathway in known mechanistic pathways that result in endothelial barrier integrity loss – vascular “leak” – primarily through a shared endothelial-epithelial signaling protein family, CCN

Effects of Salinity on Reproduction and Survival of the Calanoid Copepod Pseudodiaptomus Pelagicus

Four experiments were conducted on the calanoid copepod, Pseudodiaptomus pelagicus, to determine the effects of salinity on survival, development time, reproductive output, and population growth in order to define the optimal salinity for culture. To determine the appropriate experimental salinity range we exposed nauplii and adults to abrupt salinity changes from 35 g/L to 5, 10, 15, 35, 42, and 48 g/L at 30 °C and determined survival after 24 hours. The second experiment stocked early stage nauplii into 1 L beakers after which they were cultured using standard procedures for 10 days at six salinities (10, 15, 20, 25, 30, 35 g/L); from this survival, sex ratio, time to maturation, and fecundity were measured. The third experiment evaluated the effects of salinity on brood size, brood interval, and nauplii production by stocking individual adult pairs and monitoring nauplii production daily for 10 days. The fourth experiment determined the effects of salinity on population growth and composition of the population produced by stocking 10 adult pairs and culturing them until five days after the first mature adults were observed. Results from the abrupt salinity change experiment showed nauplii survival decreased following abrupt changes in salinity from 35 g/L to \u3c 15 g/L and \u3e 35 g/L. Additionally, adults do not tolerate rapid changes in salinity from 35 g/L to \u3c 15 g/L but are rather tolerant of changes in salinity up to 48 g/L. Survival from early nauplii to adult was not significantly affected by salinity but survival declined at 35 g/L. Time to first maturation and maturation of the entire population was significantly influenced by salinity and took from 6.3 to 9.5 days. In the individual paired adults experiment, salinity significantly affected nauplii production by affecting brood interval and brood size. The percentage of ovigerous females peaked at 20 g/L and declined at salinities above and below this value. When developing production objectives, aquaculturists must consider salinity because of its numerous effects on the culture of P. pelagicus. The optimal salinity range to achieve high survival and the greatest nauplii production is 15–25 g/L

Lifelong Multi-Agent Path Finding in Large-Scale Warehouses

Multi-Agent Path Finding (MAPF) is the problem of moving a team of agents to their goal locations without collisions. In this paper, we study the lifelong variant of MAPF, where agents are constantly engaged with new goal locations, such as in large-scale automated warehouses. We propose a new framework Rolling-Horizon Collision Resolution (RHCR) for solving lifelong MAPF by decomposing the problem into a sequence of Windowed MAPF instances, where a Windowed MAPF solver resolves collisions among the paths of the agents only within a bounded time horizon and ignores collisions beyond it. RHCR is particularly well suited to generating pliable plans that adapt to continually arriving new goal locations. We empirically evaluate RHCR with a variety of MAPF solvers and show that it can produce high-quality solutions for up to 1,000 agents (= 38.9\% of the empty cells on the map) for simulated warehouse instances, significantly outperforming existing work.Comment: Published at AAAI 202