Moduli spaces of rational graphically stable curves

2021 Summer.Includes bibliographical references.We use a graph to define a new stability condition for the algebraic and tropical moduli spaces of rational curves. Tropically, we characterize when the moduli space has the structure of a balanced fan by proving a combinatorial bijection between graphically stable tropical curves and chains of flats of a graphic matroid. Algebraically, we characterize when the tropical compactification of the compact moduli space agrees with the theory of geometric tropicalization. Both characterization results occur only when the graph is complete multipartite

Fifth Annual Idaho Public Policy Survey

The Fifth Annual Idaho Public Policy Survey was conducted December 5-13, 2019, and surveyed 1,000 adults over the age of 18 who currently live in Idaho. The sample is designed to be representative of the population of the state both geographically and demographically. This was a mixed-mode survey which contacted respondents on land line phones (33%), cell phones (33%), online (30%), and via text message (5%). The goal of using multiple means to contact respondents is to increase our coverage of the population to people who may not respond to traditional phone surveys. This survey focused on important issues facing Idaho including growth, education, taxes, and the environment. The survey has a simple random sampling margin of error of +/- 3.1% and was conducted by GS Strategies Group

Governance in the age of social machines: the web observatory

The World Wide Web has provided unprecedented access to information; as humans and machines increasingly interact with it they provide more and more data. The challenge is how to analyse and interpret this data within the context that it was created, and to present it in a way that both researchers and practitioners can more easily make sense of. The first step is to have access to open and interoperable data sets, which Governments around the world are increasingly subscribing to. But having ‘open’ data is just the beginning and does not necessarily lead to better decision making or policy development. This is because data do not provide the answers – they need to be analysed, interpreted and understood within the context of their creation, and the business imperative of the organisation using them. The major corporate entities, such as Google, Amazon, Microsoft, Apple and Facebook, have the capabilities to do this, but are driven by their own commercial imperatives, and their data are largely siloed and held within ‘walled gardens’ of information. All too often governments and non-profit groups lack these capabilities, and are driven by very different mandates. In addition they have far more complex community relationships, and must abide by regulatory constraints which dictate how they can use the data they hold. As such they struggle to maximise the value of this emerging ‘digital currency’ and are therefore largely beholden to commercial vendors. What has emerged is a public-private data ecosystem that has huge policy implications (including the twin challenges of privacy and security). Many within the public sector lack the skills to address these challenges because they lack the literacy required within the digital context. This project seeks to address some of these problems by bringing together a safe and secure Australian-based data platform (facilitating the sharing of data, analytics and visualisation) with policy analysis and governance expertise in order to create a collaborative working model of a ‘Government Web Observatory’. This neutral space, hosted by an Australian university, can serve as a powerful complement to existing Open Data initiatives in Australia, and enable research and education to combine to support the development of a more digitally literate public service. The project aims to explore where, and in which contexts, people, things, data and the Internet meet and result in evolving observable phenomena which can inform better government policy development and service delivery.&nbsp

Strongly aligned gas-phase molecules at Free-Electron Lasers

We demonstrate a novel experimental implementation to strongly align molecules at full repetition rates of free-electron lasers. We utilized the available in-house laser system at the coherent x-ray imaging beamline at the Linac Coherent Light Source. Chirped laser pulses, i. e., the direct output from the regenerative amplifier of the Ti:Sa chirped pulse amplification laser system, were used to strongly align 2,5-diiodothiophene molecules in a molecular beam. The alignment laser pulses had pulse energies of a few mJ and a pulse duration of 94 ps. A degree of alignment of \left = 0.85 was measured, limited by the intrinsic temperature of the molecular beam rather than by the available laser system. With the general availability of synchronized chirped-pulse-amplified near-infrared laser systems at short-wavelength laser facilities, our approach allows for the universal preparation of molecules tightly fixed in space for experiments with x-ray pulses.Comment: 10 pages, 5 figure

Astro2020 Science White Paper: Triggered High-Priority Observations of Dynamic Solar System Phenomena

Unexpected dynamic phenomena have surprised solar system observers in the past and have led to important discoveries about solar system workings. Observations at the initial stages of these events provide crucial information on the physical processes at work. We advocate for long-term/permanent programs on ground-based and space-based telescopes of all sizes - including Extremely Large Telescopes (ELTs) - to conduct observations of high-priority dynamic phenomena, based on a predefined set of triggering conditions. These programs will ensure that the best initial dataset of the triggering event are taken; separate additional observing programs will be required to study the temporal evolution of these phenomena. While not a comprehensive list, the following are notional examples of phenomena that are rare, that cannot be anticipated, and that provide high-impact advances to our understandings of planetary processes. Examples include: new cryovolcanic eruptions or plumes on ocean worlds; impacts on Jupiter, Saturn, Uranus, or Neptune; extreme eruptions on Io; convective superstorms on Saturn, Uranus, or Neptune; collisions within the asteroid belt or other small-body populations; discovery of an interstellar object passing through our solar system (e.g. 'Oumuamua); and responses of planetary atmospheres to major solar flares or coronal mass ejections.Comment: Astro2020 white pape

The Case for Selection at CCR5-Δ32

The C-C chemokine receptor 5, 32 base-pair deletion (CCR5-Δ32) allele confers strong resistance to infection by the AIDS virus HIV. Previous studies have suggested that CCR5-Δ32 arose within the past 1,000 y and rose to its present high frequency (5%–14%) in Europe as a result of strong positive selection, perhaps by such selective agents as the bubonic plague or smallpox during the Middle Ages. This hypothesis was based on several lines of evidence, including the absence of the allele outside of Europe and long-range linkage disequilibrium at the locus. We reevaluated this evidence with the benefit of much denser genetic maps and extensive control data. We find that the pattern of genetic variation at CCR5-Δ32 does not stand out as exceptional relative to other loci across the genome. Moreover using newer genetic maps, we estimated that the CCR5-Δ32 allele is likely to have arisen more than 5,000 y ago. While such results can not rule out the possibility that some selection may have occurred at C-C chemokine receptor 5 (CCR5), they imply that the pattern of genetic variation seen atCCR5-Δ32 is consistent with neutral evolution. More broadly, the results have general implications for the design of future studies to detect the signs of positive selection in the human genome

Shaping the development of the UKCEH UK-SCAPE Data Science Framework. Workshop report

UKCEH held an event to share progress on the development of the UK-SCAPE Data Science Framework (DSF), explore community expectations for the DSF and get feedback from the participants on whether the DSF will meet their needs. Participants were able to offer feedback through interactive voting sessions, breakout groups and a feedback form