Chandra High-Resolution X-Ray Spectrum of Supernova Remnant 1E0102.2-7219

Chandra High Energy Transmission Grating Spectrometer observations of the supernova remnant 1E0102.2-7219 in the Small Magellanic Cloud reveal a spectrum dominated by X-ray emission lines from hydrogen-like and helium-like ions of oxygen, neon, magnesium and silicon, with little iron. The dispersed spectrum shows a series of monochromatic images of the source in the light of individual spectral lines. Detailed examination of these dispersed images reveals Doppler shifts within the supernova remnant, indicating bulk matter velocities on the order of 1000 km/s. These bulk velocities suggest an expanding ring-like structure with additional substructure, inclined to the line of sight. A two-dimensional spatial/velocity map of the SNR shows a striking spatial separation of redshifted and blueshifted regions, and indicates a need for further investigation before an adequate 3D model can be found. The radii of the ring-like images of the dispersed spectrum vary with ionization stage, supporting an interpretation of progressive ionization due to passage of the reverse shock through the ejecta. Plasma diagnostics with individual emission lines of oxygen are consistent with an ionizing plasma in the low density limit, and provide temperature and ionization constraints on the plasma. Assuming a pure metal plasma, the mass of oxygen is estimated at ~6 solar masses, consistent with a massive progenitor.Comment: 47 pages, 14 figures, accepted for publication in Ap

Quantum corrections to the dynamics of interacting bosons: beyond the truncated Wigner approximation

We develop a consistent perturbation theory in quantum fluctuations around the classical evolution of a system of interacting bosons. The zero order approximation gives the classical Gross-Pitaevskii equations. In the next order we recover the truncated Wigner approximation, where the evolution is still classical but the initial conditions are distributed according to the Wigner transform of the initial density matrix. Further corrections can be characterized as quantum scattering events, which appear in the form of a nonlinear response of the observable to an infinitesimal displacement of the field along its classical evolution. At the end of the paper we give a few numerical examples to test the formalism.Comment: published versio

Non-equilibrium Gross-Pitaevskii dynamics of boson lattice models

Motivated by recent experiments on trapped ultra-cold bosonic atoms in an optical lattice potential, we consider the non-equilibrium dynamic properties of such bosonic systems for a number of experimentally relevant situations. When the number of bosons per lattice site is large, there is a wide parameter regime where the effective boson interactions are strong, but the ground state remains a superfluid (and not a Mott insulator): we describe the conditions under which the dynamics in this regime can be described by a discrete Gross-Pitaevskii equation. We describe the evolution of the phase coherence after the system is initially prepared in a Mott insulating state, and then allowed to evolve after a sudden change in parameters places it in a regime with a superfluid ground state. We also consider initial conditions with a "pi phase" imprint on a superfluid ground state (i.e. the initial phases of neighboring wells differ by pi), and discuss the subsequent appearance of density wave order and "Schrodinger cat" states.Comment: 16 pages, 11 figures; (v2) added reference

Mapping Children's Discussions of Evidence in Science to Assess Collaboration and Argumentation

The research reported in this paper concerns the development of children's skills of interpreting and evaluating evidence in science. Previous studies have shown that school teaching often places limited emphasis on the development of these skills, which are necessary for children to engage in scientific debate and decision-making. The research, undertaken in the UK, involved four collaborative decision-making activities to stimulate group discussion, each was carried out with five groups of four children (10-11 years old). The research shows how the children evaluated evidence for possible choices and judged whether their evidence was sufficient to support a particular conclusion or the rejection of alternative conclusions. A mapping technique was developed to analyse the discussions and identify different "levels" of argumentation. The authors conclude that suitable collaborative activities that focus on the discussion of evidence can be developed to exercise children's ability to argue effectively in making decisions

Developing cardiac and skeletal muscle share fast-skeletal myosin heavy chain and cardiac troponin-I expression

Skeletal muscle derived stem cells (MDSCs) transplanted into injured myocardium can differentiate into fast skeletal muscle specific myosin heavy chain (sk-fMHC) and cardiac specific troponin-I (cTn-I) positive cells sustaining recipient myocardial function. We have recently found that MDSCs differentiate into a cardiomyocyte phenotype within a three-dimensional gel bioreactor. It is generally accepted that terminally differentiated myocardium or skeletal muscle only express cTn-I or sk-fMHC, respectively. Studies have shown the presence of non-cardiac muscle proteins in the developing myocardium or cardiac proteins in pathological skeletal muscle. In the current study, we tested the hypothesis that normal developing myocardium and skeletal muscle transiently share both sk-fMHC and cTn-I proteins. Immunohistochemistry, western blot, and RT-PCR analyses were carried out in embryonic day 13 (ED13) and 20 (ED20), neonatal day 0 (ND0) and 4 (ND4), postnatal day 10 (PND10), and 8 week-old adult female Lewis rat ventricular myocardium and gastrocnemius muscle. Confocal laser microscopy revealed that sk-fMHC was expressed as a typical striated muscle pattern within ED13 ventricular myocardium, and the striated sk-fMHC expression was lost by ND4 and became negative in adult myocardium. cTn-I was not expressed as a typical striated muscle pattern throughout the myocardium until PND10. Western blot and RT-PCR analyses revealed that gene and protein expression patterns of cardiac and skeletal muscle transcription factors and sk-fMHC within ventricular myocardium and skeletal muscle were similar at ED20, and the expression patterns became cardiac or skeletal muscle specific during postnatal development. These findings provide new insight into cardiac muscle development and highlight previously unknown common developmental features of cardiac and skeletal muscle. © 2012 Clause et al

The developmental effects of media-ideal internalization and self-objectification processes on adolescents’ negative body-feelings, dietary restraint, and binge eating

Despite accumulated experimental evidence of the negative effects of exposure to media-idealized images, the degree to which body image, and eating related disturbances are caused by media portrayals of gendered beauty ideals remains controversial. On the basis of the most up-to-date meta-analysis of experimental studies indicating that media-idealized images have the most harmful and substantial impact on vulnerable individuals regardless of gender (i.e., “internalizers” and “self-objectifiers”), the current longitudinal study examined the direct and mediated links posited in objectification theory among media-ideal internalization, self-objectification, shame and anxiety surrounding the body and appearance, dietary restraint, and binge eating. Data collected from 685 adolescents aged between 14 and 15 at baseline (47 % males), who were interviewed and completed standardized measures annually over a 3-year period, were analyzed using a structural equation modeling approach. Results indicated that media-ideal internalization predicted later thinking and scrutinizing of one’s body from an external observer’s standpoint (or self-objectification), which then predicted later negative emotional experiences related to one’s body and appearance. In turn, these negative emotional experiences predicted subsequent dietary restraint and binge eating, and each of these core features of eating disorders influenced each other. Differences in the strength of these associations across gender were not observed, and all indirect effects were significant. The study provides valuable information about how the cultural values embodied by gendered beauty ideals negatively influence adolescents’ feelings, thoughts and behaviors regarding their own body, and on the complex processes involved in disordered eating. Practical implications are discussed

Targeting mitochondrial responses to intra-articular fracture to prevent posttraumatic osteoarthritis

We tested whether inhibiting mechanically responsive articular chondrocyte mitochondria after severe traumatic injury and preventing oxidative damage represent a viable paradigm for posttraumatic osteoarthritis (PTOA) prevention. We used a porcine hock intra-articular fracture (IAF) model well suited to human-like surgical techniques and with excellent anatomic similarities to human ankles. After IAF, amobarbital or N-acetylcysteine (NAC) was injected to inhibit chondrocyte electron transport or downstream oxidative stress, respectively. Effects were confirmed via spectrophotometric enzyme assays or glutathione/glutathione disulfide assays and immunohistochemical measures of oxidative stress. Amobarbital or NAC delivered after IAF provided substantial protection against PTOA at 6 months, including maintenance of proteoglycan content, decreased histological disease scores, and normalized chondrocyte metabolic function. These data support the therapeutic potential of targeting chondrocyte metabolism after injury and suggest a strong role for mitochondria in mediating PTOA

Use of Complex Lie Symmetries for Linearization of Systems of Differential Equations - II: Partial Differential Equations

The linearization of complex ordinary differential equations is studied by extending Lie's criteria for linearizability to complex functions of complex variables. It is shown that the linearization of complex ordinary differential equations implies the linearizability of systems of partial differential equations corresponding to those complex ordinary differential equations. The invertible complex transformations can be used to obtain invertible real transformations that map a system of nonlinear partial differential equations into a system of linear partial differential equation. Explicit invariant criteria are given that provide procedures for writing down the solutions of the linearized equations. A few non-trivial examples are mentioned.Comment: This paper along with its first part ODE-I were combined in a single research paper "Linearizability criteria for systems of two second-order differential equations by complex methods" which has been published in Nonlinear Dynamics. Due to citations of both parts I and II these are not replaced with the above published articl

Pediatric Health-Related Quality of Life: Feasibility, Reliability and Validity of the PedsQL™ Transplant Module

The measurement properties of the newly developed Pediatric Quality of Life Inventory™ (PedsQL™) 3.0 Transplant Module in pediatric solid organ transplant recipients were evaluated. Participants included pediatric recipients of liver, kidney, heart and small bowel transplantation who were cared for at seven medical centers across the United States and their parents. Three hundred and thirty-eight parents of children ages 2–18 and 274 children ages 5–18 completed both the PedsQL™ 4.0 Generic Core Scales and the Transplant Module. Findings suggest that child self-report and parent proxy-report scales on the Transplant Module demonstrated excellent reliability (total scale score for child self-report α= 0.93; total scale score for parent proxy-report α= 0.94). Transplant-specific symptoms or problems were significantly correlated with lower generic HRQOL, supporting construct validity. Children with solid organ transplants and their parents reported statistically significant lower generic HRQOL than healthy children. Parent and child reports showed moderate to good agreement across the scales. In conclusion, the PedsQL™ Transplant Module demonstrated excellent initial feasibility, reliability and construct validity in pediatric patients with solid organ transplants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79306/1/j.1600-6143.2010.03149.x.pd

The Interplanetary Network Supplement to the Fermi GBM Catalog - An AO-2 and AO-3 Guest Investigator Project

In the first two years of operation of the Fermi GBM, the 9-spacecraft Interplanetary Network (IPN) detected 158 GBM bursts with one or two distant spacecraft, and triangulated them to annuli or error boxes. Combining the IPN and GBM localizations leads to error boxes which are up to 4 orders of magnitude smaller than those of the GBM alone. These localizations comprise the IPN supplement to the GBM catalog, and they support a wide range of scientific investigations