E0 emission in alpha + ^12C fusion at astrophysical energies

We show that E0 emission in alpha + ^12C fusion at astrophysically interesting energies is negligible compared to E1 and E2 emission.Comment: submitted to Phys. Rev. C, Brief Report

Comment on "Electromagnetic dissociation of ^8B and the astrophysical S-factor for ^7Be(p,gamma)^8B"

Recently, Davids and Typel recommended a "low" value of S_{17}(0) based on fits to published direct and Coulomb dissociation data, in which they excluded the precise result of Junghans et al. We show that their statistical analysis is incorrect, due to a substantial underestimate of the experimental uncertainties, and leads to conclusions that are not supported by a proper analysis.Comment: submitted to Phys. Rev.

Coastal Impacts of Climate Change in the Northwest: A Summary of the Findings of the upcoming National Climate Assessment

The many thousands of miles of Northwest marine coastline are extremely diverse and contain important human-built and natural assets upon which our communities and ecosystems depend. Due to the variety of coastal landform types (e.g., sandy beaches, rocky shorelines, bluffs of varying slopes and composition, river deltas, and estuaries), the region’s marine coastal areas stand to experience a wide range of climate impacts, in both type and severity. These impacts include increases in ocean temperature and acidity, erosion, and more severe and frequent inundation from the combined effects of rising sea levels and storms, among others.Increases in coastal inundation and erosion are key concerns. A recent assessment determined that the coastal areas of Washington and Oregon contain over 56,656 hectares(140,000 acres) of land within 1.0-meter (3.3-feet) elevation of high tide (Strauss et al. 2012).Rising sea levels coupled with the possibility of intensifying coastal storms will increase the likelihood of more severe coastal flooding and erosion in these areas.The Northwest is also facing the challenge of increasing ocean acidification, and is experiencing these changes earlier, and more acutely, than most other regions around the globe(NOAA OAR 2012).The Third National Climate Assessment is scheduled for release in the spring of 2014.The authors will provide an overview of the key Northwest coastal findings in this report as well as a summary of its primary companion report published by Island Press in December 2013,Climate Change in the Northwest: Implications for Our Landscapes, Waters, and Communities(Dalton et al 2013)

Rep-tiling for triangles

AbstractIn this paper we prove that one can only tile a triangle with tiles all congruent to each other and similar to the original triangle when k2, l2 + k2, or 3k2 tiles are used. The result is based on the geometry of packing and a result of I. Niven's on rational trigonometric values. In addition we describe how to tile most triangles

Prevalence of sessile serrated adenoma/polyp in hyperplastic appearing diminutive rectosigmoid polyps

Background The American Society for Gastrointestinal Endoscopy recommends that distal colon hyperplastic lesions can be left in place without resection if adenomatous histology can be excluded with > 90% negative predictive value. However, some of the lesions could be sessile serrated adenoma/polyp (SSA/P), which is also precancerous. Aim Describe the prevalence of SSA/P in hyperplastic appearing diminutive rectosigmoid polyps. Methods We prospectively placed 513 consecutive diminutive rectosigmoid polyps that appeared hyperplastic to an expert endoscopist in individual bottles for pathologic examination. Each polyp was examined by 3 expert gastrointestinal pathologists. Results The prevalence of SSA/P in the study polyps ranged from 0.6% to 2.1%. The endoscopists lowest negative predictive value for the combination of adenomas plus SSA/P was 96.7% Conclusions The prevalence of SSA/P in diminutive rectosigmoid hyperplastic appearing polyps is very low. These results support the safety and feasibility of a “do not resect” policy for diminutive hyperplastic appearing rectosigmoid polyps

A Limited Symmetry Found by Comparing Calculated Magnetic Dipole Spin and Orbital Strengths in ^4\mbox{He}

Allowing for $2$$\hbar \omega$ admixtures in ^4\mbox{He} we find that the summed magnetic dipole isovector orbital and spin strengths are equal. This indicates a symmetry which is associated with interchanging the labels of the spin with those of the orbit. Where higher admixtures are included, the orbital sum becomes larger than the spin sum, but the sums over the low energy region are still nearly the same.Comment: 13 pages, revtex, 1 ps file appende

Scaling Properties of the Giant Dipole Resonance Width in Hot Rotating nuclei

We study the systematics of the giant dipole resonance width $\Gamma$ in hot rotating nuclei as a function of temperature $T$, spin $J$ and mass $A$. We compare available experimental results with theoretical calculations that include thermal shape fluctuations in nuclei ranging from A=45 to A=208. Using the appropriate scaled variables, we find a simple phenomenological function $\Gamma(A,T,J)$ which approximates the global behavior of the giant dipole resonance width in the liquid drop model. We reanalyze recent experimental and theoretical results for the resonance width in Sn isotopes and $^{208}$Pb.Comment: LaTeX, 4 pages with 4 figures (to appear in Phys. Rev. Lett.

Absolute Determination of the 22Na(p,g) Reaction Rate in Novae

Gamma-ray telescopes in orbit around the Earth are searching for evidence of the elusive radionuclide 22Na produced in novae. Previously published uncertainties in the dominant destructive reaction, 22Na(p,g)23Mg, indicated new measurements in the proton energy range of 150 to 300 keV were needed to constrain predictions. We have measured the resonance strengths, energies, and branches directly and absolutely by using protons from the University of Washington accelerator with a specially designed beamline, which included beam rastering and cold vacuum protection of the 22Na implanted targets. The targets, fabricated at TRIUMF-ISAC, displayed minimal degradation over a ~ 20 C bombardment as a result of protective layers. We avoided the need to know the stopping power, and hence the target composition, by extracting resonance strengths from excitation functions integrated over proton energy. Our measurements revealed that resonance strengths for E_p = 213, 288, 454, and 610 keV are stronger by factors of 2.4 to 3.2 than previously reported. Upper limits have been placed on proposed resonances at 198-, 209-, and 232-keV. We have re-evaluated the 22Na(p,g) reaction rate, and our measurements indicate the resonance at 213 keV makes the most significant contribution to 22Na destruction in novae. Hydrodynamic simulations including our rate indicate that the expected abundance of 22Na ejecta from a classical nova is reduced by factors between 1.5 and 2, depending on the mass of the white-dwarf star hosting the nova explosion.Comment: 20 pages, 18 figures; shortened paper, accepted in Phys. Rev.

Findings in the Distal Colorectum are not associated with Proximal Advanced Serrated Lesions

Background & Aims Serrated lesions are an important contributor to colorectal cancer (CRC), notably in the proximal colon. Findings in the distal colorectum are markers of advanced proximal adenomatous neoplasia. However, it is not known whether they affect the odds of advanced proximal serrated lesions. Methods We performed a retrospective cross-sectional study of data from 1910 patients (59.3 ± 8.0 years, 53.8% female) who underwent an average-risk screening colonoscopy from August 2005 through April 2012 at Indiana University Hospital and an associated ambulatory surgery center. Colonoscopies were performed by an endoscopist with high rates of detection of adenomas and serrated polyps. Tissue samples of all serrated polyps (hyperplastic, sessile serrated adenoma/polyp [SSA/P], or traditional serrated adenoma) proximal to the sigmoid colon and serrated polyps >5 mm in the rectum or sigmoid colon were reviewed by a gastrointestinal pathologist and reclassified on the basis of World Health Organization criteria. Advanced serrated lesion (ASL) was defined as SSA/P with cytologic dysplasia, SSA/P ≥10 mm, or traditional serrated adenoma. Advanced conventional adenomatous neoplasia (ACN) was defined as tubular adenoma ≥10 mm, villous histology, high-grade dysplasia, or cancer. The prevalence of proximal ASL and ACN was calculated on the basis of distal colorectal findings. Multivariable logistic regression analysis was performed to determine the age-adjusted and sex-adjusted odds of advanced proximal adenomatous and serrated lesions. Secondary analyses were performed to examine the effect of variable ASL definitions. Results Fifty-two patients (2.7%) had proximal ASL, and 99 (5.2%) had proximal ACN. Of the 52 patients with proximal ASL, 27 (52%) had no distal polyps. Of the 99 patients with proximal ACN, 40 (40%) had no distal polyps. Age and type of distal adenomas were significantly associated with proximal ACN. There were no significant associations between distal polyp type and proximal ASL. In secondary analyses, distal SSA/Ps (P = .008) but not distal hyperplastic polyps or conventional adenomas were associated with any proximal SSA/P. Conclusions The findings at flexible sigmoidoscopy that traditionally serve as indications for colonoscopy (conventional adenomas) are likely to be ineffective for detection of proximal ASL. This finding, plus the observation that most patients with proximal ASL have no distal polyps, favors screening colonoscopy over sigmoidoscopy, especially in the elderly. The observation that non-advanced distal SSA/Ps are associated with any proximal SSA/P warrants further study