The local electronic structure of alpha-Li3N

New theoretical and experimental investigation of the occupied and unoccupied local electronic density of states (DOS) are reported for alpha-Li3N. Band structure and density functional theory calculations confirm the absence of covalent bonding character. However, real-space full-multiple-scattering (RSFMS) calculations of the occupied local DOS finds less extreme nominal valences than have previously been proposed. Nonresonant inelastic x-ray scattering (NRIXS), RSFMS calculations, and calculations based on the Bethe-Salpeter equation are used to characterize the unoccupied electronic final states local to both the Li and N sites. There is good agreement between experiment and theory. Throughout the Li 1s near-edge region, both experiment and theory find strong similarities in the s- and p-type components of the unoccupied local final density of states projected onto an orbital angular momentum basis (l-DOS). An unexpected, significant correspondence exists between the near-edge spectra for the Li 1s and N 1s initial states. We argue that both spectra are sampling essentially the same final density of states due to the combination of long core-hole lifetimes, long photoelectron lifetimes, and the fact that orbital angular momentum is the same for all relevant initial states. Such considerations may be generically applicable for low atomic number compounds.Comment: 34 pages, 7 figures, 1 tabl

The grinch who stole wisdom

Dr. Seuss is wise. How the Grinch Stole Christmas (Seuss, 1957) could serve as a parable for our time. It can also be seen as a roadmap for the development of contemplative wisdom. The abiding popularity of How the Grinch Stole Christmas additionally suggests that contemplative wisdom is more readily available to ordinary people, even children, than is normally thought. This matters because from the point of view of contemplatives in any of the world's philosophies or religions, people are confused about wisdom. The content of the nascent field of wisdom studies, they might say, is largely not wisdom at all but rather what it's like to live in a particular kind of prison cell, a well appointed cell perhaps, but not a place that makes possible either personal satisfaction or deep problem solving. I believe that what the contemplative traditions have to say is important; they offer a different orientation to what personal wisdom is, how to develop it, and how to use it in the world than is presently contained in either our popular culture or our sciences. In order to illustrate this I will examine, in some detail, one contemplative path within Buddhism. Buddhism is particularly useful in this respect because its practices are nontheistic and thus avoid many of the cultural landmines associated with the contemplative aspects of Western religions

Early stages of ramified growth in quasi-two-dimensional electrochemical deposition

I have measured the early stages of the growth of branched metal aggregates formed by electrochemical deposition in very thin layers. The growth rate of spatial Fourier modes is described qualitatively by the results of a linear stability analysis [D.P. Barkey, R.H. Muller, and C.W. Tobias, J. Electrochem. Soc. {\bf 136}, 2207 (1989)]. The maximum growth rate is proportional to $(I/c)^\delta$ where $I$ is the current through the electrochemical cell, $c$ the electrolyte concentration, and $\delta = 1.37 \pm 0.08$. Differences between my results and the theoretical predictions suggest that electroconvection in the electrolyte has a large influence on the instability leading to ramified growth.Comment: REVTeX, four ps figure

SAMPLING OF CORN TO ASSESS BIRD DAMAGE: A Preliminary Review of a Comprehensive Study

How large a sample is needed to survey the bird damage to corn in a county in Ohio or New Jersey or South Dakota? Like those in the Bureau of Sport Fisheries and Wildlife and the U.S.D.A. who have been faced with a question of this sort we found only meager information on which to base an answer, whether the problem related to a county in Ohio or to one in New Jersey, or elsewhere. Many sampling methods and rates of sampling did yield reliable estimates but the judgment was often intuitive or based on the reasonableness of the resulting data. Later, when planning the next study or survey, little additional information was available on whether 40 samples of 5 ears each or 5 samples of 200 ears should be examined, i.e., examination of a large number of small samples or a small number of large samples. What information is needed to make a reliable decision? Those of us involved with the Agricultural Experiment Station regional project concerned with the problems of bird damage to crops, known as NE-49, thought we might supply an ans¬wer if we had a corn field in which all the damage was measured. If all the damage were known, we could then sample this field in various ways and see how the estimates from these samplings compared to the actual damage and pin-point the best and most accurate sampling procedure. Eventually the investigators in four states became involved in this work1 and instead of one field we were able to broaden the geographical base by examining all the corn ears in 2 half-acre sections of fields in each state, 8 sections in all. When the corn had matured well past the dough stage, damage on each corn ear was assessed, without removing the ear from the stalk, by visually estimating the percent of the kernel surface which had been destroyed and rating it in one of 5 damage categories. Measurements (by row-centimeters) of the rows of kernels pecked by birds also were made on selected ears representing all categories and all parts of each field section. These measurements provided conversion factors that, when fed into a computer, were applied to the more than 72,000 visually assessed ears. The machine now had in its memory and could supply on demand a map showing each ear, its location and the intensity of the damage

Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches

The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of $^{238}$U$_{e}$~$<$1.6~mBq/kg, $^{238}$U$_{l}$~$<$0.09~mBq/kg, $^{232}$Th$_{e}$~$=0.28\pm 0.03$~mBq/kg, $^{232}$Th$_{l}$~$=0.25\pm 0.02$~mBq/kg, $^{40}$K~$<$0.54~mBq/kg, and $^{60}$Co~$<$0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of $0.160\pm0.001$(stat)$\pm0.030$(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle Physic

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment

LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4×10-48 cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3×10-43 cm2 (7.1×10-42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020

Diabetes and pancreatic cancer survival: A prospective cohort-based study

BACKGROUND: Diabetes is a risk factor for pancreatic cancer but its association with survival from pancreatic cancer is poorly understood. Our objective was to investigate the association of diabetes with survival among pancreatic cancer patients in a prospective cohort-based study where diabetes history was ascertained before pancreatic cancer diagnosis. METHODS: We evaluated survival by baseline (1993–2001) self-reported diabetes history (n=62) among 504 participants that developed exocrine pancreatic cancer within the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality were estimated using Cox proportional hazards model, adjusted for age, sex, body mass index, race, smoking, and tumour stage (local, locally advanced, and metastatic). RESULTS: The multivariable-adjusted HR for mortality comparing participants with diabetes to those without was 1.52 (95% CI=1.14–2.04, P-value <0.01). After excluding those diagnosed with pancreatic cancer within 3 years of study enrolment, HR for mortality among those with diabetes was 1.45 (95% CI=1.06–2.00, P-value=0.02). CONCLUSIONS: Using prospectively collected data, our findings indicate that diabetes is associated with worse survival among patients with pancreatic cancer