Signatures of r-process elements in kilonova spectra

Binary neutron star (NS) mergers have been expected to synthesize r-process elements and emit radioactively powered radiation, called kilonova. Although r-process nucleosynthesis was confirmed by the observations of GW170817/AT2017gfo, no trace of individual elements has been identified except for strontium. In this paper, we perform systematic calculations of line strength for bound-bound transitions and radiative transfer simulations in NS merger ejecta toward element identification in kilonova spectra. We find that Sr II triplet lines appear in the spectrum of a lanthanide-poor model, which is consistent with the absorption feature observed in GW170817/AT2017gfo. The synthetic spectrum also shows the strong Ca II triplet lines. This is natural because Ca and Sr are co-produced in the material with relatively high electron fraction and their ions have similar atomic structures with only one s-electron in the outermost shell. The line strength, however, highly depends on the abundance distribution and temperature in the ejecta. For our lanthanide-rich model, the spectra show the features of doubly ionized heavy elements, such as Ce, Tb and Th. Our results suggest that the line forming region of GW170817/AT2017gfo was lanthanide-poor. We show that the Sr II and Ca II lines can be used as a probe of physical conditions in NS merger ejecta. Absence of the Ca II line features in GW170817/AT2017gfo implies that the Ca/Sr ratio is = 0.40 and entropy per nucleon (in units of Boltzmann constant) >= 25

Lanthanide Features in Near-infrared Spectra of Kilonovae

The observations of GW170817/AT2017gfo have provided us with evidence thatbinary neutron star mergers are sites of $r$-process nucleosynthesis. However,the observed signatures in the spectra of GW170817/AT2017gfo have not beenfully decoded especially in the near-infrared (NIR) wavelengths. In this paper,we investigate the kilonova spectra over the entire wavelength range with theaim of elemental identification. We systematically calculate the strength ofbound-bound transitions by constructing a hybrid line list that is accurate forimportant strong transitions and complete for weak transitions. We find thatthe elements on the left side of the periodic table, such as Ca, Sr, Y, Zr, Ba,La, and Ce, tend to produce prominent absorption lines in the spectra. This isbecause such elements have a small number of valence electrons and low-lyingenergy levels, resulting in strong transitions. By performing self-consistentradiative transfer simulations for the entire ejecta, we find that La III andCe III appear in the NIR spectra, which can explain the absorption features at$\lambda\sim 12000$-14000 A in the spectra of GW170817/AT2017gfo. The massfractions of La and Ce are estimated to be $>2\times 10^{-6}$ and $\sim$(1-100)$\times 10^{-5}$, respectively. An actinide element Th can also be asource of absorption as the atomic structure is analogous to that of Ce.However, we show that Th III features are less prominent in the spectra becauseof the denser energy levels of actinides compared to those of lanthanides.<br

Comparing Integrated Pest Management and Protectant Strategies for Control of Apple Scab and Codling Moth in an Iowa Apple Orchard

Integrated peat management (IPM) strategies for control of apple scab and codling moth (Cydia pomonolla) were compared with a traditional protestant spray program in an Iowa apple orchard over a 3-year period. IPM tactics for scab included a postinfection spray program and an integrated, reduced-spray program based on the use of demethylation inhibitor fungicides. Codling moth spray timing was determined by pheromone-trap captures and degree-day models. The IPM tactics resulted in an average of three fewer fungicide sprays and two fewer insecticide sprays than the protestant program. Neither yield, incidence of fruit scab, nor incidence of codling moth injury on fruit was significantly different among the two IPM treatments and the protestant treatment. A no-fungicide treatment had significantly lower yield and greater scab incidence than the other treatments. A partial budget analysis indicated that the treatment using the postinfection strategy was more costly per acre than the protectant program for orchardsacres, about equivalent in cost for 20 acres, but leas costly for 40 acres. A treatment incorporating the integrated, reduced-spray strategy was less costly than either postinfection or protestant strategies at orchard sizes from 5 to 40 acres. Return (total revenue - cost for control of primary scab and codling moth) per acre for the IPM strategies was somewhat lower than for the protestant program

The role of phonological and orthographic information in lexical selection

Theoretical and Experimental Linguistic

Effect of Shear Surface Boundaries on Stress for Shearing Flow of Dry Metal Powders-An Experimental Study

I Introduction The mechanical behavior of granular materials is important in a wide variety of industrial, engineering, and scientific fields. Despite this many aspects of the behavior of flowing granular solids are still not well understood primarily because experimental observations of the details of such flows are quite sparse. However, experiments to test dry, cohesionless, granular materials at high shear-rates have recently been developed by The motivation for this study arose from the process of xerography. In this process a dry powder image is formed upon a xerographic plate by optical and electrostatic mechanisms. Toner, a dry, thermoplastic powder, is used and the powder image is then transferred to a sheet of ordinary Contributed by the Tribology Division of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS and presented at the ASME/ASLE Joint Tribology Conference, Pittsburgh, PA, October 20-22, 1986. Manuscript received by the Tribology Division March 8, 1986. Paper No. 86-Trib-8. paper. This process relies upon the use of both a magnetic field and the use of flow of metal powders to transport the thermoplastic powder. In this paper both the shear and normal stress results are reported for the rapid flow of aluminum beads. These results are compared with the results for the rapid flow of carbon steel beads reported earlier by Craig, Buckholz, and Domoto (1986). One of the central issues related to the prediction of granular material flow is characterization of its material properties. One view, the one adopted in this paper, is a continuum approach. Another view could consider the dynamics of the individual particles. The continuum mechanics pointof-view to describe the granular flow involves determining an appropriate constitutive equation. Experimental methods similar to those used in the characterization of fluid properties are used. Therefore, we focus on the issue of stress as a function of shear-rate. The purpose of this experiment is to study the stresses associated with the shearing motion of metal powers. The results obtained can guide the theoretical development of constitutive equations for metal powders. Stress measurements are obtained that are analogous to the type obtained in rheological tests of both viscous fluids and solid suspensions. In this experiment it is essential to control as many of the independent parameters as possible. One of these independent parameters, the fractional solids content, is the ratio of the volume occupied by the granular material to the shear-cell test volume. This parameter is maintained at a prescribed constant value for a range of experimental conditions. The average stresses on the top drive surface are then 232/Vol. 109, APRIL 1987 Transactions of the ASM

Effects of spatial dispersion in near-field radiative heat transfer between two parallel metallic surfaces

We study the heat transfer between two parallel metallic semi-infinite media with a gap in the nanometer-scale range. We show that the near-field radiative heat flux saturates at distances smaller than the metal skin depth when using a local dielectric constant and investigate the origin of this effect. The effect of non-local corrections is analysed using the Lindhard-Mermin and Boltzmann-Mermin models. We find that local and non-local models yield the same heat fluxes for gaps larger than 2 nm. Finally, we explain the saturation observed in a recent experiment as a manifestation of the skin depth and show that heat is mainly dissipated by eddy currents in metallic bodies.Comment: Version without figures (8 figures in the complete version

Annexin II represents metastatic potential in clear-cell renal cell carcinoma

BACKGROUND: Annexin II (ANX2) is a multi-functional protein involved in cell proliferation and membrane physiology and is related to cancer progression. The purpose of this study was to assess ANX2 expression in clear-cell (cc) renal cell carcinoma (RCC)

Attitudes Toward Advance Care Planning Among Persons with Dementia and their Caregivers

Objectives: To examine factors that influence decision-making, preferences, and plans related to advance care planning (ACP) and end-of-life care among persons with dementia and their caregivers, and examine how these may differ by race. Design: Cross-sectional survey. Setting: 13 geographically dispersed Alzheimer's Disease Centers across the United States. Participants: 431 racially diverse caregivers of persons with dementia. Measurements: Survey on "Care Planning for Individuals with Dementia." Results: The respondents were knowledgeable about dementia and hospice care, indicated the person with dementia would want comfort care at the end stage of illness, and reported high levels of both legal ACP (e.g., living will; 87%) and informal ACP discussions (79%) for the person with dementia. However, notable racial differences were present. Relative to white persons with dementia, African American persons with dementia were reported to have a lower preference for comfort care (81% vs. 58%) and lower rates of completion of legal ACP (89% vs. 73%). Racial differences in ACP and care preferences were also reflected in geographic differences. Additionally, African American study partners had a lower level of knowledge about dementia and reported a greater influence of religious/spiritual beliefs on the desired types of medical treatments. Notably, all respondents indicated that more information about the stages of dementia and end-of-life health care options would be helpful. Conclusions: Educational programs may be useful in reducing racial differences in attitudes towards ACP. These programs could focus on the clinical course of dementia and issues related to end-of-life care, including the importance of ACP

Alternative splicing in a presenilin 2 variant associated with Alzheimer disease

Objective: Autosomal-dominant familial Alzheimer disease (AD) is caused by by variants in presenilin 1 (PSEN1), presenilin 2 (PSEN2), and amyloid precursor protein (APP). Previously, we reported a rare PSEN2 frameshift variant in an early-onset AD case (PSEN2 p.K115Efs*11). In this study, we characterize a second family with the same variant and analyze cellular transcripts from both patient fibroblasts and brain lysates. Methods: We combined genomic, neuropathological, clinical, and molecular techniques to characterize the PSEN2 K115Efs*11 variant in two families. Results: Neuropathological and clinical evaluation confirmed the AD diagnosis in two individuals carrying the PSEN2 K115Efs*11 variant. A truncated transcript from the variant allele is detectable in patient fibroblasts while levels of wild-type PSEN2 transcript and protein are reduced compared to controls. Functional studies to assess biological consequences of the variant demonstrated that PSEN2 K115Efs*11 fibroblasts secrete less Aβ₁-₄₀ compared to controls, indicating abnormal γ-secretase activity. Analysis of PSEN2 transcript levels in brain tissue revealed alternatively spliced PSEN2 products in patient brain as well as in sporadic AD and age-matched control brain. Interpretation: These data suggest that PSEN2 K115Efs*11 is a likely pathogenic variant associated with AD. We uncovered novel PSEN2 alternative transcripts in addition to previously reported PSEN2 splice isoforms associated with sporadic AD. In the context of a frameshift, these alternative transcripts return to the canonical reading frame with potential to generate deleterious protein products. Our findings suggest novel potential mechanisms by which PSEN variants may influence AD pathogenesis, highlighting the complexity underlying genetic contribution to disease risk.Jacquelyn E. Braggin, Stephanie A. Bucks, Meredith M. Course, Carole L. Smith, Bryce Sopher, Leah Osnis, Kiel D. Shuey, Kimiko Domoto-Reilly, Christina Caso, Chizuru Kinoshita, Kathryn P. Scherpelz, Chloe Cross, Thomas Grabowski, Seyyed H.M. Nik, Morgan Newman, Gwenn A. Garden, James B. Leverenz, Debby Tsuang, Caitlin Latimer, Luis F. Gonzalez-Cuyar, Christopher Dirk Keene, Richard S. Morrison, Kristoffer Rhoads, Ellen M. Wijsman, Michael O. Dorschner, Michael Lardelli, Jessica E. Young, Paul N. Valdmanis, Thomas D. Bird, Suman Jayade