The flavor of product-group GUTs

The doublet-triplet splitting problem can be simply solved in product-group GUT models, using a global symmetry that distinguishes the doublets from the triplets. Apart from giving the required mass hierarchy, this ``triplet symmetry'' can also forbid some of the triplet couplings to matter. We point out that, since this symmetry is typically generation-dependent, it gives rise to non-trivial flavor structure. Furthermore, because flavor symmetries cannot be exact, the triplet-matter couplings are not forbidden then but only suppressed. We construct models in which the triplet symmetry gives acceptable proton decay rate and fermion masses. In some of the models, the prediction m_b ~ m_\tau is retained, while the similar relation for the first generation is corrected. Finally, all this can be accomplished with triplets somewhat below the GUT scale, supplying the right correction for the standard model gauge couplings to unify precisely.Comment: 10 page

A detailed X-ray investigation of zeta Puppis IV. Further characterization of the variability

Previously, the X-ray emission of zeta Puppis was found to be variable with light curves harbouring "trends" with a typical timescale longer than the exposure length. The origin of these changes was proposed to be linked to large-scale structures in the wind, but further characterization of the variability at high energies was needed. Since then, a number of new X-ray observations have become available. Furthermore, a cyclic behaviour with a 1.78d period was identified in long optical photometric runs, which is thought to be associated with the launching mechanism of large-scale wind structures. We analysed these new X-ray data, revisited the old data, and compared X-ray with optical data, including when simultaneous. We found that the behaviour in X-rays cannot be explained in terms of a perfect clock because the amplitude and shape of its variations change with time. For example, zeta Puppis was much more strongly variable between 2007 and 2011 than before and after this interval. Comparing the X-ray spectra of the star at maximum and minimum brightness yields no compelling difference beyond the overall flux change: the temperatures, absorptions, and line shapes seem to remain constant, well within errors. The only common feature between X-ray datasets is that the variation amplitudes appear maximum in the medium (0.6-1.2keV) energy band. Finally, no clear and coherent correlation can be found between simultaneous X-ray and optical data. Only a subgroup of observations may be combined coherently with the optical period of 1.78d, although the simultaneous optical behaviour is unknown. The currently available data do not reveal any obvious, permanent, and direct correlation between X-ray and optical variations. The origin of the X-ray variability therefore still needs to be ascertained, highlighting the need for long-term monitoring in multiwavelengths, i.e. X-ray, UV, and optical.Comment: accepted for publication by A&

Equivariant Index and the Moment Map for Completely Integrable Torus Actions

AbstractConsider a completely integrable torus action on a compact Spincmanifold. The equivariant index of the Dirac operator is a virtual representation of the torus and is determined by the multiplicities of the weights which occur it in. We prove that these multiplicities are equal to values of the density function for the Duistermaat–Heckman measure, once this is defined appropriately. (The two-form that we take is half of the curvature of the line bundle which is associated to the Spincstructure. It is closed and invariant but not necessarily symplectic.) We deduce that these multiplicities are equal to the topological degree of the “descended moment map”Φ:M/T→t*, which in nice cases can be described as sums of certain winding numbers

Beyond Monetary Compensation: The Need for Comprehensive Services for the Wrongfully Convicted

Twenty-two states, the District of Columbia, and the Federal Government currently have statutory mechanisms in place to provide compensation for wrongfully convicted individuals. Most of these statutes focus on the need for monetary compensation for individuals who have spent years in prison for crimes they did not commit. Only three of these statutes also provide meaningful post-release services. This is despite the fact that these programs are critical to address the unique reentry obstacles that face wrongfully convicted individuals and to ensure successful reintegration into society. This article examines the need for all states to provide meaningful post-release services to wrongfully convicted individuals. Focusing on the Massachusetts statute—the first compensation statute to include a meaningful services provision—the authors also assert that non-monetary “compensation” should include reentry services immediately upon release that are at least comparable to those received by parolees, but yet are tailored to the distinct needs of wrongfully convicted individuals

Atrial Arrhythmias in Astronauts - Summary of a NASA Summit

Background and Problem Definition: To evaluate NASA s current standards and practices related to atrial arrhythmias in astronauts, Space Medicine s Advanced Projects Section at the Johnson Space Center was tasked with organizing a summit to discuss the approach to atrial arrhythmias in the astronaut cohort. Since 1959, 11 cases of atrial fibrillation, atrial flutter, or supraventricular tachycardia have been recorded among active corps crewmembers. Most of the cases were paroxysmal, although a few were sustained. While most of the affected crewmembers were asymptomatic, those slated for long-duration space flight underwent radiofrequency ablation treatment to prevent further episodes of the arrhythmia. The summit was convened to solicit expert opinion on screening, diagnosis, and treatment options, to identify gaps in knowledge, and to propose relevant research initiatives. Summit Meeting Objectives: The Atrial Arrhythmia Summit brought together a panel of six cardiologists, including nationally and internationally renowned leaders in cardiac electrophysiology, exercise physiology, and space flight cardiovascular physiology. The primary objectives of the summit discussions were to evaluate cases of atrial arrhythmia in the astronaut population, to understand the factors that may predispose an individual to this condition, to understand NASA s current capabilities for screening, diagnosis, and treatment, to discuss the risks associated with treatment of crewmembers assigned to long-duration missions or extravehicular activities, and to discuss recommendations for prevention or management of future cases. Summary of Recommendations: The summit panel s recommendations were grouped into seven categories: Epidemiology, Screening, Standards and Selection, Treatment of Atrial Fibrillation Manifesting Preflight, Atrial Fibrillation during Flight, Prevention of Atrial Fibrillation, and Future Researc

The Near Earth Asteroid Medical Conditions List

Purpose: The Exploration Medical Capability (ExMC) element is one of six elements within NASA s Human Research Program (HRP) and is responsible for addressing the risk of "the inability to adequately recognize or treat an ill or injured crewmember" for exploration-class missions. The Near Earth Asteroid (NEA) Medical Conditions List, constructed by ExMC, is the first step in addressing the above-mentioned risk for the 13-month long NEA mission. The NEA mission is being designed by NASA's Human Space Flight Architecture Team (HAT). The purpose of the conditions list is to serve as an evidence-based foundation for determining which medical conditions could affect a crewmember during the NEA mission, which of those conditions would be of concern and require treatment, and for which conditions a gap in knowledge or technology development exists. This information is used to focus research efforts and technology development to ensure that the appropriate medical capabilities are available for exploration-class missions. Scope and Approach: The NEA Medical Conditions List is part of a broader Space Medicine Exploration Medical Conditions List (SMEMCL), which incorporates various exploration-class design reference missions (DRMs). The conditions list contains 85 medical conditions which could occur during space flight and which are derived from several sources: Long-Term Surveillance of Astronaut Health (LSAH) in-flight occurrence data, The Space Shuttle (STS) Medical Checklist, The International Space Station (ISS) Medical Checklist, and subject matter expert opinion. Each medical condition listed has been assigned a clinical priority and a clinical priority rationale based on incidence, consequence, and mitigation capability. Implementation: The conditions list is a "living document" and as such, new conditions can be added to the list, and the priority of conditions on the list can be adjusted as the DRM changes, and as screening, diagnosis, or treatment capabilities change. The NEA medical conditions list was used recently as the basis for identifying gaps in in-flight medical evaluation (screening) capabilities. Learning Objectives: The audience will become familiar with the approach taken by NASA's Exploration Medical Capability element in addressing the risk of inability to recognize and treat medical conditions in the setting of a Near Earth Asteroid mission. Which one of the following statements is incorrect? a) The Near Earth Asteroid (NEA) medical conditions list includes 85 medical conditions which could occur during space flight. b) Each condition on the NEA medical conditions list has been assigned a clinical priority and a clinical priority rationale. c) The NEA medical conditions list targets a mission to Mars. d) The NEA medical conditions list should be viewed as a "living document" where new conditions can be added and clinical priorities adjusted to address changes in the design reference mission or medical capabilities. The incorrect answer is c). The NEA medical conditions list targets a mission to a Near Earth Asteroid

Local Overweighting and Underperformance: Evidence from Limited Partner Private Equity Investments

Institutional investors of all types exhibit substantial home-state bias when investing in private equity (PE) funds. This effect is particularly pronounced for public pension funds, where the local overweighting amounts to 9.7% of the private equity portfolio on average, based on 5-year rolling average benchmarks. Public pension funds’ own-state investments perform significantly worse than their out-of-state investments, an average of 3-4 percentage points of net IRR per year, and those that that overweight their portfolios towards home-state investments also perform worse overall. These underperformance patterns are not evident for other types of institutional investors, such as endowments, foundations and corporate pension funds, and we do not observe similar overweighting or underperformance of investments in neighboring states. Overweighting in home state investments by public pension funds is greater in states with higher levels of corruption, although there is no positive correlation of underperformance with corruption for these investors. The overweighting and underperformance of local investments cost public pension funds between $0.9 and$1.2 billion per year, depending on the benchmark.

Needle in a Haystack: Finding Supermassive Black Hole-Related Flares in the Zwicky Transient Facility Public Survey

Transient accretion events onto supermassive black holes (SMBHs), such as tidal disruption events (TDEs), Bowen Fluorescence Flares (BFFs), and active galactic nuclei (AGNs), which are accompanied by sudden increases of activity, offer a new window onto the SMBH population, accretion physics, and stellar dynamics in galaxy centers. However, such transients are rare and finding them in wide-field transient surveys is challenging. Here we present the results of a systematic real-time search for SMBH-related transients in Zwicky Transient Facility (ZTF) public alerts, using various search queries. We examined 345 rising events coincident with a galaxy nucleus, with no history of previous activity, of which 223 were spectroscopically classified. Of those, five (2.2%) were TDEs, one (0.5%) was a BFF, and two (0.9%) were AGN flares. Limiting the search to blue events, the fraction of TDEs nearly doubles to 4.1%, and no TDEs are missed. Limiting the search further to candidate post-starburst galaxies increases the relative number of TDEs to 16.7%, but the absolute numbers in such a search are small. The main contamination source is supernovae (95.1% of classified events), of which the majority (82.2% of supernovae) are of Type Ia. In a comparison set of 39 events with limited photometric history, the AGN contamination increases to ~30%. Host galaxy offset is not a significant discriminant of TDEs in current ZTF data, but might be useful in higher-resolution data. Our results can be used to quantify the efficiency of various SMBH-related transient search strategies in optical surveys such as ZTF and the Legacy Survey of Space and Time.Comment: Accepted to Ap