The Wave Properties of Coronal Bright Fronts Observed Using SDO/AIA

Coronal bright fronts (CBFs) are large scale wavefronts that propagate though the solar corona at hundreds of kilometers per second. While their kinematics have been studied in detail, many questions remain regarding the temporal evolution of their amplitude and pulse width. Here, contemporaneous high cadence, multi-thermal observations of the solar corona from the Solar Dynamic Observatory (SDO) and Solar TErrestrial RElations Observatory (STEREO) spacecraft are used to determine the kinematics and expansion rate of a CBF wavefront observed on 2010 August 14. The CBF was found to have a lower initial velocity with weaker deceleration in STEREO observations compared to SDO (~340 km/s and -72 m/s/s as opposed to ~410 km/s and -279 m/s/s). The CBF kinematics from SDO were found to be highly passband-dependent, with an initial velocity ranging from 379+/-12 km/s to 460+/-28 km/s and acceleration ranging from -128+/-28 m/s/s to -431+/-86 m/s/s in the 335A and 304A passbands respectively. These kinematics were used to estimate a quiet coronal magnetic field strength range of ~1-2 G. Significant pulse broadening was also observed, with expansion rates of ~130 km/s (STEREO) and ~220 km/s (SDO). By treating the CBF as a linear superposition of sinusoidal waves within a Gaussian envelope, the resulting dispersion rate of the pulse was found to be ~8-13 Mm^2 s^-1. These results are indicative of a fast-mode magnetoacoustic wave pulse propagating through an inhomogeneous medium.Comment: 14 pages, 2 figures. Accepted for publication in The Astrophysical Journal Letter

Increasing Skin Infections and Staphylococcus aureus Complications in Children, England, 1997-2006

During 1997-2006, general practitioner consultations for skin conditions for children <18 years of age in England increased 19%, from 128.5 to 152.9/1,000 child-years, and antistaphylococcal drug prescription rates increased 64%, from 17.8 to 29.1/1,000 child-years. During the same time period, hospital admissions for Staphylococcus aureus infections rose 49% from 53.4 to 79.3/100,000 child-years.link_to_subscribed_fulltex

Protein kinase A regulates gene-specific translational adaptation in differentiating yeast

Cellular differentiation is driven by coordinately regulated changes in gene expression. Recent discoveries suggest that translation contributes as much as transcription to regulating protein abundance, but the role of translational regulation in cellular differentiation is largely unexplored. Here we investigate translational reprogramming in yeast during cellular adaptation to the absence of glucose, a stimulus that induces invasive filamentous differentiation. Using ribosome footprint profiling and RNA sequencing to assay gene-specific translation activity genome-wide, we show that prolonged glucose withdrawal is accompanied by gene-specific changes in translational efficiency that significantly affect expression of the majority of genes. Notably, transcripts from a small minority (<5%) of genes make up the majority of translating mRNA in both rapidly dividing and starved differentiating cells, and the identities of these highly translated messages are almost nonoverlapping between conditions. Furthermore, these two groups of messages are subject to condition-dependent translational privilege. Thus the “housekeeping” process of translation does not stay constant during cellular differentiation but is highly adapted to different growth conditions. By comparing glucose starvation to growth-attenuating stresses that do not induce invasive filamentation, we distinguish a glucose-specific translational response mediated through signaling by protein kinase A (PKA). Together, these findings reveal a high degree of growth-state specialization of the translatome and identify PKA as an important regulator of gene-specific translation activity.National Institutes of Health (U.S.) (R01 GM094303

Electron correlation energy in confined two-electron systems

Radial, angular and total correlation energies are calculated for four two-electron systems with atomic numbers Z=0-3 confined within an impenetrable sphere of radius R. We report accurate results for the non-relativistic, restricted Hartree-Fock and radial limit energies over a range of confinement radii from 0.05 - 10 a0. At small R, the correlation energies approach limiting values that are independent of Z while at intermediate R, systems with Z > 1 exhibit a characteristic maximum in the correlation energy resulting from an increase in the angular correlation energy which is offset by a decrease in the radial correlation energy

Secondary Waves, and/or the "Reflection" From and "Transmission" Through a Coronal Hole of an EUV Wave Associated With the 2011 February 15 X2.2 Flare Observed With SDO/AIA and STEREO/EUVI

For the first time, the kinematic evolution of a coronal wave over the entire solar surface is studied. Full Sun maps can be made by combining images from the Solar Terrestrial Relations Observatory satellites, Ahead and Behind, and the Solar Dynamics Observatory, thanks to the wide angular separation between them. We study the propagation of a coronal wave, also known as "EIT" wave, and its interaction with a coronal hole resulting in secondary waves and/or reflection and transmission. We explore the possibility of the wave obeying the law of reflection of waves. In a detailed example we find that a loop arcade at the coronal hole boundary cascades and oscillates as a result of the EUV wave passage and triggers a wave directed eastwards that appears to have reflected. We find that the speed of this wave decelerates to an asymptotic value, which is less than half of the primary EUV wave speed. Thanks to the full Sun coverage we are able to determine that part of the primary wave is transmitted through the coronal hole. This is the first observation of its kind. The kinematic measurements of the reflected and transmitted wave tracks are consistent with a fast-mode MHD wave interpretation. Eventually, all wave tracks decelerate and disappear at a distance. A possible scenario of the whole process is that the wave is initially driven by the expanding coronal mass ejection and subsequently decouples from the driver and then propagates at the local fast-mode speed.Comment: 30 pages, 12 figures, accepted for publication in Ap

First SDO AIA Observations of a Global Coronal EUV "Wave": Multiple Components and "Ripples"

We present the first SDO AIA observations of a global coronal EUV disturbance (so-called "EIT wave") revealed in unprecedented detail. The disturbance observed on 2010 April 8 exhibits two components: one diffuse pulse superimposed on which are multiple sharp fronts that have slow and fast components. The disturbance originates in front of erupting coronal loops and some sharp fronts undergo accelerations, both effects implying that the disturbance is driven by a CME. The diffuse pulse, propagating at a uniform velocity of 204-238 km/s with very little angular dependence within its extent in the south, maintains its coherence and stable profile for ~30 minutes. Its arrival at increasing distances coincides with the onsets of loop expansions and the slow sharp front. The fast sharp front overtakes the slow front, producing multiple "ripples" and steepening the local pulse, and both fronts propagate independently afterwards. This behavior resembles the nature of real waves. Unexpectedly, the amplitude and FWHM of the diffuse pulse decrease linearly with distance. A hybrid model, combining both wave and non-wave components, can explain many, but not all, of the observations. Discoveries of the two-component fronts and multiple ripples were made possible for the first time thanks to AIA's high cadences (10-20 s) and high signal-to-noise ratio.Comment: 7 pages, 5 figure

The Gilbert Arborescence Problem

We investigate the problem of designing a minimum cost flow network interconnecting n sources and a single sink, each with known locations in a normed space and with associated flow demands. The network may contain any finite number of additional unprescribed nodes from the space; these are known as the Steiner points. For concave increasing cost functions, a minimum cost network of this sort has a tree topology, and hence can be called a Minimum Gilbert Arborescence (MGA). We characterise the local topological structure of Steiner points in MGAs, showing, in particular, that for a wide range of metrics, and for some typical real-world cost-functions, the degree of each Steiner point is 3.Comment: 19 pages, 7 figures. arXiv admin note: text overlap with arXiv:0903.212

Challenges and opportunities in abdominal aortic aneurysm research

AbstractAbdominal Aortic Aneurysms (AAAs) are associated with advanced age, male gender, cigarette smoking, atherosclerosis, hypertension, and genetic predisposition. Basic research studies have led to a better understanding of aneurysm disease over the past two decades. There has also been a growing appreciation that fundamental knowledge regarding the process of aneurysmal degeneration is still somewhat limted. Opportunities in research include: 1) the investigation of potential new mechanism-based pharmacologic interventions; 2) identify the genetic basis for an inherited predisposition; 3) develop and refine noninvasive approaches for the early detection; 4) examine potential novel surgical approaches and design new biomaterials; and 5) initiate and promote awareness programs for diagnosis and treatment of aortic aneurysms. The optimal approach to addressing these issues will require integrative, multidisciplinary research programs that involve basic scientists working in concert with vascular and cardiothoracic surgeons, as well as other clinical specialists with expertise in vascular disease

Valuation of Scholarly Activities for Physical Therapy Faculty

Purpose/Hypothesis: Physical therapy (PT) faculty are required to participate in scholarly endeavors. Scholarly productivity is frequently evaluated based on quantity of production.1-3 This approach fails to account for quality (e.g. authorship order, presentation audience, or funding). Study aims: 1) compare PT program scholarly productivity valuations between programs of varying Carnegie Classification, 2) establish a scholarly activity measure which accounts for quality, and 3) provide an applied example of the new measure. Number of Subjects: PT Program Directors from CAPTE institutions (n=226) were surveyed using Dillman’s protocol.4 Materials/Methods: Respondents were asked to value (0 – 20) 30 scholarly activities (e.g., grants, publications, presentations, patents). A peer reviewed publication was the benchmark (score of 10) to which all options were compared. Nine additional questions asked about bonus value (0-100%) for impact factor, authorship order, role on a grant, and grant competitiveness. The mean for each component was the value that component contributed to the Scholar Score. Comparisons were performed via ANOVA models. Results: We received 59 responses (response rate 26%) from Professors (n=28), Associate Profs (n=28), and Assistant Profs (n=3) from institutions of Carnegie Classifications: Doctoral (n=26), Masters (n=22), and Special Focus (n=11). Significant effects of classification were observed for two of the bonus items: Last Author (p=.015) and Role as Co- PI/PI on a Grant (p=.03). Post hoc comparisons using the Bonferroni correction indicated Last Author and Grant Role assigned bonuses were less for Masters programs than for Doctoral programs [(M=25.9, SD=28.7 vs. M=53.5, SD=34.4, p=.02) and (M=49.0, SD=32.5 vs. M=77.3, SD=36.7, p=.03), respectively]. No other pairwise comparisons were significant. Responses were used to develop a Scholar Score based on perceived quality. Scholarly achievements from curriculum vitaes of two early-career PT faculty demonstrates the application of this new measure. While the numerical count of their scholarly products was identical, Scholar Scores differed by \u3e70%. Conclusions: The Scholar Score was developed from PT Program Director input. Directors from different Carnegie Classified institutions reported similar values for most components. This indicates the Scholar Score may be generalizable to PT faculty across all Carnegie Classifications. Our application example demonstrates how quantity and quality-based descriptions differ. Clinical Relevance : Scholarly activity plays an integral role in the career advancement of the PT faculty. A Scholar Score offers a clear and uniform, peer validated approach to the valuation of scholarly activities for PT educators. KEYWORDS: faculty development, research, early career. References Kaufman RR. Career factors help predict productivity in scholarship among faculty members in physical therapist education programs. Phys Ther. 03;89(3):204-216. Hinman MR, Brown T. Changing profile of the physical therapy professoriate--are we meeting CAPTE\u27s expectations? J Phys Ther Educ. 2017;31(4):95-104. Emerick, T., et al. (2013). Scholarly activity points: a new tool to evaluate resident scholarly productivity. British Journal Of Anaesthesia 111(3): 468-476. Dillman DA. Mail and internet surveys: The tailored design method. Hoboken, NJ: John Wiley & Sons; 2000. Tscharntke T. Author sequence and credit for contributions in multiauthored publications. PLoS biology. 01;5(1):e18. Richter RR. Journal publication productivity in academic physical therapy programs in the United States and Puerto Rico from 1998 to 2002. Phys Ther. 03;88(3):376-386