A Calculus for Higher Spin Interactions

Higher spin theories can be efficiently described in terms of auxiliary St\"uckelberg or projective space field multiplets. By considering how higher spin models couple to scale, these approaches can be unified in a conformal geometry/tractor calculus framework. We review these methods and apply them to higher spin vertices to obtain a generating function for massless, massive and partially massless three-point interactions.Comment: 24 pages, 3 figures, LaTex. References added, typos corrected. Final version to appear in JHE

A Pilot Study of Uncertainty in Income Tax Forecasts

How confidently can taxpayers forecast the tax bill that they will face? We asked survey respondents to provide both point estimates and subjective probability distributions of items from the tax return that they will submit the following April. In a pilot study, consisting of a sample of 188 participants from Amazon Mechanical Turk, we find evidence of substantial uncertainty over both the final tax and its determinants. We discuss the implications of this uncertainty for both tax policy and economic modeling

The M81 Group Dwarf Irregular Galaxy DDO 165. II. Connecting Recent Star Formation with ISM Structures and Kinematics

We compare the stellar populations and complex neutral gas dynamics of the M81 group dIrr galaxy DDO 165 using data from the HST and the VLA. Paper I identified two kinematically distinct HI components, multiple localized high velocity gas features, and eight HI holes and shells (the largest of which spans ~2.2x1.1 kpc). Using the spatial and temporal information from the stellar populations in DDO 165, we compare the patterns of star formation over the past 500 Myr with the HI dynamics. We extract localized star formation histories within 6 of the 8 HI holes identified in Paper I, as well as 23 other regions that sample a range of stellar densities and neutral gas properties. From population synthesis modeling, we derive the energy outputs (from stellar winds and supernovae) of the stellar populations within these regions over the last 100 Myr, and compare with refined estimates of the energies required to create the HI holes. In all cases, we find that "feedback" is energetically capable of creating the observed structures in the ISM. Numerous regions with significant energy inputs from feedback lack coherent HI structures but show prominent localized high velocity gas features; this feedback signature is a natural product of temporally and spatially distributed star formation. In DDO 165, the extended period of heightened star formation activity (lasting more than 1 Gyr) is energetically capable of creating the observed holes and high velocity gas features in the neutral ISM.Comment: The Astrophysical Journal, in press. Full-resolution version available on request from the first autho

Winter weather and lake-watershed physical configuration drive phosphorus, iron, and manganese dynamics in water and sediment of ice-covered lakes

While decreasing occurrence and duration of lake ice cover is well-documented, biogeochemical dynamics in frozen lakes remain poorly understood. Here, we interpret winter physical and biogeochemical time series from eutrophic Missisquoi Bay (MB) and hyper-eutrophic Shelburne Pond (SP) to describe variable drivers of under ice biogeochemistry in systems of fundamentally different lake-watershed physical configurations (lake area, lake : watershed area). The continuous cold of the 2015 winter drove the MB sediment-water interface to the most severe and persistent suboxic state ever documented at this site, promoting the depletion of redox-sensitive phases in sediments, and an expanding zone of bottom water enriched in reactive species of Mn, Fe, and P. In this context, lake sediment and water column inventories of reactive chemical species were sensitive to the severity and persistence of subfreezing temperatures. During thaws, event provenance and severity impact lake thermal structure and mixing, water column enrichment in P and Fe, and thaw capability to suppress redox front position and internal chemical loading. Nearly identical winter weather manifest differently in nearby SP, where the small surface and watershed areas promoted a warmer, less stratified water column and active phytoplankton populations, impacting biogeochemical dynamics. In SP, Fe and P behavior under ice were decoupled due to active biological cycling, and thaw impacts were different in distribution and composition due to SP's physical structure and related antecedent conditions. We find that under ice biogeochemistry is highly dynamic in both time and space and sensitive to a variety of drivers impacted by climate change

Engineered zinc finger nickases induce homology-directed repair with reduced mutagenic effects

Engineered zinc finger nucleases (ZFNs) induce DNA double-strand breaks at specific recognition sequences and can promote efficient introduction of desired insertions, deletions or substitutions at or near the cut site via homology-directed repair (HDR) with a double- and/or single-stranded donor DNA template. However, mutagenic events caused by error-prone non-homologous end-joining (NHEJ)-mediated repair are introduced with equal or higher frequency at the nuclease cleavage site. Furthermore, unintended mutations can also result from NHEJ-mediated repair of off-target nuclease cleavage sites. Here, we describe a simple and general method for converting engineered ZFNs into zinc finger nickases (ZFNickases) by inactivating the catalytic activity of one monomer in a ZFN dimer. ZFNickases show robust strand-specific nicking activity in vitro. In addition, we demonstrate that ZFNickases can stimulate HDR at their nicking site in human cells, albeit at a lower frequency than by the ZFNs from which they were derived. Finally, we find that ZFNickases appear to induce greatly reduced levels of mutagenic NHEJ at their target nicking site. ZFNickases thus provide a promising means for inducing HDR-mediated gene modifications while reducing unwanted mutagenesis caused by error-prone NHEJ

Astrocytes mediate synapse elimination through MEGF10 and MERTK pathways

To achieve its precise neural connectivity, the developing mammalian nervous system undergoes extensive activity-dependent synapse remodeling. Recently microglial cells have been shown to be responsible for a portion of synaptic remodeling, but the remaining mechanisms remain mysterious. Here we report a new role for astrocytes in actively engulfing CNS synapses. This process helps to mediate synapse elimination, requires the Megf10 and Mertk phagocytic pathways, and is strongly dependent on neuronal activity. Developing mice deficient in both astrocyte pathways fail to normally refine their retinogeniculate connections and retain excess functional synapses. Lastly, we show that in the adult mouse brain, astrocytes continuously engulf both excitatory and inhibitory synapses. These studies reveal a novel role for astrocytes in mediating synapse elimination in the developing and adult brain, identify Megf10 and Mertk as critical players in the synapse remodeling underlying neural circuit refinement, and have important implications for understanding learning and memory as well as neurological disease processes

The M81 Group Dwarf Irregular Galaxy DDO 165. I. High Velocity Neutral Gas in a Post-Starburst System

We present new multi-configuration VLA HI spectral line observations of the M81 group dIrr post-starburst galaxy DDO 165. The HI morphology is complex, with multiple column density peaks surrounding a large region of very low HI surface density that is offset from the center of the stellar distribution. The bulk of the neutral gas is associated with the southern section of the galaxy; a secondary peak in the north contains ~15% of the total HI mass. These components appear to be kinematically distinct, suggesting that either tidal processes or large-scale blowout have recently shaped the ISM of DDO 165. Using spatially-resolved position-velocity maps, we find multiple localized high-velocity gas features. Cross-correlating with radius-velocity analyses, we identify eight shell/hole structures in the ISM with a range of sizes (~400-900 pc) and expansion velocities (~7-11 km/s). These structures are compared with narrow- and broad-band imaging from KPNO and HST. Using the latter data, recent works have shown that DDO 165's previous "burst" phase was extended temporally (>1 Gyr). We thus interpret the high-velocity gas features, HI holes, and kinematically distinct components of the galaxy in the context of the immediate effects of "feedback" from recent star formation. In addition to creating HI holes and shells, extended star formation events are capable of creating localized high velocity motion of the surrounding interstellar material. A companion paper connects the energetics from the HI and HST data.Comment: The Astrophysical Journal, in press. Full-resolution version available on request from the first autho

Outflow Driven Turbulence in Molecular Clouds

In this paper we explore the relationship between protostellar outflows and turbulence in molecular clouds. Using 3-D numerical simulations we focus on the hydrodynamics of multiple outflows interacting within a parsec scale volume. We explore the extent to which transient outflows injecting directed energy and momentum into a sub-volume of a molecular cloud can be converted into random turbulent motions. We show that turbulence can readily be sustained by these interactions and show that it is possible to broadly characterize an effective driving scale of the outflows. We compare the velocity spectrum obtained in our studies to that of isotropically forced hydrodynamic turbulence finding that in outflow driven turbulence a power law is indeed achieved. However we find a steeper spectrum (beta ~ 3) is obtained in outflow driven turbulence models than in isotropically forced simulations (beta ~ 2). We discuss possible physical mechanisms responsible for these results as well and their implications for turbulence in molecular clouds where outflows will act in concert with other processes such as gravitational collapse.Comment: 12 pages, 3 figure

Extending a structural model of somatization to South Koreans: Cultural values, somatization tendency, and the presentation of depressive symptoms

Background: Somatization refers to the tendency to emphasize somatic symptoms when experiencing a psychiatric disturbance. This tendency has been widely reported in patients from East Asian cultural contexts suffering from depression. Recent research in two Chinese samples have demonstrated that the local cultural script for depression, involving two aspects—the experience and expression of distress (EED) and conceptualization and communication of distress (CCD)—can be evoked to help explain somatization. Given the beliefs and practices broadly shared across Chinese and South Korean cultural contexts, the current study seeks to replicate this explanatory model in South Koreans. Methods: Our sample included 209 psychiatric outpatients from Seoul and Wonju, South Korea. Self-report questionnaires were used to assess somatization tendency, adherence to traditional values, and psychological and somatic symptoms of depression. Results: Results from SEM showed that the EED and CCD factors of somatization tendency were differently associated with cultural values and somatic symptoms, replicating our previous findings in Chinese outpatients. Limitations: The reliance on a brief self-report measure of somatization tendency, not originally designed to assess separate EED and CCD factors, highlights the need for measurement tools for the assessment of cultural scripts in cross-cultural depression research. Conclusions: The replication of the Chinese structural model of somatization in South Korealends empirical support to the view that somatization can be understood as the consequence of specific cultural scripts. These scripts involve the experience and expression of distress as well as culturally meaningful ways in which this distress is conceptualized and communicated to other