In-flight PSF calibration of the NuSTAR hard X-ray optics

We present results of the point spread function (PSF) calibration of the hard X-ray optics of the Nuclear Spectroscopic Telescope Array (NuSTAR). Immediately post-launch, NuSTAR has observed bright point sources such as Cyg X-1, Vela X-1, and Her X-1 for the PSF calibration. We use the point source observations taken at several off-axis angles together with a ray-trace model to characterize the in-orbit angular response, and find that the ray-trace model alone does not fit the observed event distributions and applying empirical corrections to the ray-trace model improves the fit significantly. We describe the corrections applied to the ray-trace model and show that the uncertainties in the enclosed energy fraction (EEF) of the new PSF model is < 3% for extraction apertures of R > 60" with no significant energy dependence. We also show that the PSF of the NuSTAR optics has been stable over a period of ~300 days during its in-orbit operation.Comment: 10 pages, 6 figures. Presented at the SPIE conference Astronomical Telescopes + Instrumentation 201

PILOTs: What Are They and Are They Affected by Institutional and/or Economic Constraints? The Case of Wisconsin Municipalities

Following the rise of tax and expenditure limitations in the 1970s, scholars have focused on assessing the effects of these limitations on local government fiscal outcomes. One key takeaway has been local governments’ decreasing reliance on property taxes and increased use of nontax revenue sources, in particular fees and changes. This study builds on this work by focusing on a particular type of fee—that is, payments in lieu of taxes (PILOTs). We find that, in Wisconsin, revenues received by municipalities from two PILOTs programs are affected quite differently. The extent to which the economy, municipal fiscal condition, tax and expenditure limits, and community characteristics affect PILOTs’ revenues depends on the extent to which the municipality can manipulate the payment structure

Broadband X-ray Imaging and Spectroscopy of the Crab Nebula and Pulsar with NuSTAR

We present broadband (3 -- 78 keV) NuSTAR X-ray imaging and spectroscopy of the Crab nebula and pulsar. We show that while the phase-averaged and spatially integrated nebula + pulsar spectrum is a power-law in this energy band, spatially resolved spectroscopy of the nebula finds a break at $\sim$9 keV in the spectral photon index of the torus structure with a steepening characterized by $\Delta\Gamma\sim0.25$. We also confirm a previously reported steepening in the pulsed spectrum, and quantify it with a broken power-law with break energy at $\sim$12 keV and $\Delta\Gamma\sim0.27$. We present spectral maps of the inner 100\as\ of the remnant and measure the size of the nebula as a function of energy in seven bands. These results find that the rate of shrinkage with energy of the torus size can be fitted by a power-law with an index of $\gamma = 0.094\pm 0.018$, consistent with the predictions of Kennel and Coroniti (1984). The change in size is more rapid in the NW direction, coinciding with the counter-jet where we find the index to be a factor of two larger. NuSTAR observed the Crab during the latter part of a $\gamma$-ray flare, but found no increase in flux in the 3 - 78 keV energy band

Supporting Fathers in Multi-Ethnic Societies: Insights from British Asian Fathers

AbstractThere is concern that current UK policy and intervention aimed at supporting fathers remains primarily informed by dominant White middle-class values and experiences, and therefore fails to respond adequately to the needs of Britain's diverse fathers. This paper contributes to understanding of ethnic diversity in fathering contexts, practices and experiences, by reporting findings from a qualitative study of British Asian fathers, involving in-depth interviews with fifty-nine fathers and thirty-three mothers from Bangladeshi Muslim, Pakistani Muslim, Gujarati Hindu and Punjabi Sikh background, and over eight additional respondents engaged through Key Informant interviews, ethnographic interviews and group discussions. The paper highlights four areas that require greater recognition by policy-makers and practitioners to appropriately meet the needs of fathers from diverse ethnic and socio-economic backgrounds. These are: recognising that fathers and mothers do not necessarily constitute an autonomous unit; appreciating diversity in fathers’ understandings of desirable child outcomes; addressing additional obstacles to achieving similar outcomes for children; and understanding that the boundaries and content of fathering are not universally recognised. Policies that are less normative and more responsive to diversity are essential to ensure that all fathers can be effectively supported.</jats:p

Laser actuation of cantilevers for picometre amplitude dynamic force microscopy

As nanoscale and molecular devices become reality, the ability to probe materials on these scales is increasing in importance. To address this, we have developed a dynamic force microscopy technique where the flexure of the microcantilever is excited using an intensity modulated laser beam to achieve modulation on the picoscale. The flexure arises from thermally induced bending through differential expansion and the conservation of momentum when the photons are reflected and absorbed by the cantilever. In this study, we investigated the photothermal and photon pressure responses of monolithic and layered cantilevers using a modulated laser in air and immersed in water. The developed photon actuation technique is applied to the stretching of single polymer chains

Impact of Pediatric Obesity on Grades in Elementary School

Objective: The current study examines the relationship between obesity and academic performance among second grade students. We hypothesized that students who were overweight or obese would have poorer grades than students who were normal weight. Design: Cross-sectional. Setting: Seven elementary schools from a southeast Texas Independent School District. Participants: The sample was composed of 798 ethnically and racially diverse elementary school children. Students were classified as normal weight, overweight, and obese. Main Outcome Measures: Differences in cumulative grades (math, science, and reading) across weight classifications were examined using sex, race/ethnicity, and school socioeconomic level as covariates. Additionally, all subject areas were analyzed independently. Analysis: Linear mixed models and follow-up pairwise comparisons. Results:The linear mixed model revealed significant differences in grades across weight classifications (p\u3c.05). Conclusions and Implications: This study suggests that weight status is an important marker of scholastic success. Addressing overweight may bolster efforts to improve academic performance

The use of segmented regression in analysing interrupted time series studies : an example in pre-hospital ambulance care

Peer reviewedPublisher PD

Neutron Characterization for Additive Manufacturing

Oak Ridge National Laboratory (ORNL) is leveraging decades of experience in neutron characterization of advanced materials together with resources such as the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) shown in Fig. 1 to solve challenging problems in additive manufacturing (AM). Additive manufacturing, or three-dimensional (3-D) printing, is a rapidly maturing technology wherein components are built by selectively adding feedstock material at locations specified by a computer model. The majority of these technologies use thermally driven phase change mechanisms to convert the feedstock into functioning material. As the molten material cools and solidifies, the component is subjected to significant thermal gradients, generating significant internal stresses throughout the part (Fig. 2). As layers are added, inherent residual stresses cause warping and distortions that lead to geometrical differences between the final part and the original computer generated design. This effect also limits geometries that can be fabricated using AM, such as thin-walled, high-aspect- ratio, and overhanging structures. Distortion may be minimized by intelligent toolpath planning or strategic placement of support structures, but these approaches are not well understood and often "Edisonian" in nature. Residual stresses can also impact component performance during operation. For example, in a thermally cycled environment such as a high-pressure turbine engine, residual stresses can cause components to distort unpredictably. Different thermal treatments on as-fabricated AM components have been used to minimize residual stress, but components still retain a nonhomogeneous stress state and/or demonstrate a relaxation-derived geometric distortion. Industry, federal laboratory, and university collaboration is needed to address these challenges and enable the U.S. to compete in the global market. Work is currently being conducted on AM technologies at the ORNL Manufacturing Demonstration Facility (MDF) sponsored by the DOE's Advanced Manufacturing Office. The MDF is focusing on R&D of both metal and polymer AM pertaining to in-situ process monitoring and closed-loop controls; implementation of advanced materials in AM technologies; and demonstration, characterization, and optimization of next-generation technologies. ORNL is working directly with industry partners to leverage world-leading facilities in fields such as high performance computing, advanced materials characterization, and neutron sciences to solve fundamental challenges in advanced manufacturing. Specifically, MDF is leveraging two of the world's most advanced neutron facilities, the HFIR and SNS, to characterize additive manufactured components

Tectonic evolution of the early Mesozoic blueschist-bearing Qiangtang metamorphic belt, central Tibet

This is the published version. Copyright 2003 American Geophysical Union. All Rights Reserved.A >500-km-long east-west trending metamorphic belt in the Qiangtang terrane of central Tibet consists of tectonic melange that occurs in the footwalls of Late Triassic–Early Jurassic domal low-angle normal faults. The melange is comprised of a strongly deformed matrix of metasedimentary and mafic schists that encloses lesser-deformed blocks of metabasites, Carboniferous–Triassic metasedimentary rocks, and early Paleozoic gneiss. Both the blocks and melange matrix exhibit greenschist, epidote-blueschist, and locally, epidote-amphibolite facies mineral assemblages. Thermobarometry reveals that the metamorphic belt experienced pressures of >10 kbar. Maximum equilibration temperatures for mafic schists in the melange matrix decrease from east to west, from ∼660°C near Shuang Hu (33°N, 89°E), ∼500°C near Rongma (33°N, 87°E), to ∼425°C near Gangma Co (34°N, 84°E). Equilibration at consistently high pressures over a large range of temperatures is compatible with metamorphism of Qiangtang melange within a low-angle subduction zone beneath a continental margin. Coupled structural, thermobarometric, and 40Ar/39Ar studies suggest that Qiangtang melange was exhumed in an intracontinental setting from depths of >35 km to upper crustal levels in <12 Myr by Late Triassic–Early Jurassic crustal-scale normal faulting. Detrital zircons from metasandstones within the melange matrix yield U-Pb ion-microprobe ages that range from early Paleozoic to Early Archean, and could have been sourced from terranes to the north of the Jinsha suture. Our results support a model in which Qiangtang melange was underthrust ∼200 km beneath the Qiangtang terrane during early Mesozoic flat-slab southward subduction of Paleo-Tethyan oceanic lithosphere along the Jinsha suture. This model predicts that significant portions of the central Tibetan continental mantle lithosphere were removed during early Mesozoic low-angle oceanic subduction and that the present-day central Tibetan deeper crust includes large volumes of underthrust early Mesozoic melange