Perfection of materials technology for producing improved Gunn-effect devices Interim scientific report

Chemical vapor deposition of epitaxial gallium arsenid

Constraining Radon Backgrounds in LZ

The LZ dark matter detector, like many other rare-event searches, will suffer from backgrounds due to the radioactive decay of radon daughters. In order to achieve its science goals, the concentration of radon within the xenon should not exceed $2\mu$Bq/kg, or 20 mBq total within its 10 tonnes. The LZ collaboration is in the midst of a program to screen all significant components in contact with the xenon. The four institutions involved in this effort have begun sharing two cross-calibration sources to ensure consistent measurement results across multiple distinct devices. We present here five preliminary screening results, some mitigation strategies that will reduce the amount of radon produced by the most problematic components, and a summary of the current estimate of radon emanation throughout the detector. This best estimate totals $<17.3$ mBq, sufficiently low to meet the detector's science goals.Comment: Low Radioactivity Techniques (LRT) 2017 Workshop Proceedings. 6 pages; 3 figure

Our Reflections on the Reactions to “Theories in the Field of Community Psychology”

We recognize that our article (Jason, Stevens, Ram, Miller, Beasley, &amp; Gleason, 2016) will be controversial, and we are delighted that it has sparked some lively discussions. Our thesis is that research in our field could benefit from being evaluated on how it contributes to theory (including the development of one’s own). We believe that this recommendation represents a significant and constructive step forward. Our reflections on a number of the issues raised by those who wrote reactions to our article are below

Our Reflections on the Reactions to “Theories in the Field of Community Psychology”

We recognize that our article (Jason, Stevens, Ram, Miller, Beasley, &amp; Gleason, 2016) will be controversial, and we are delighted that it has sparked some lively discussions. Our thesis is that research in our field could benefit from being evaluated on how it contributes to theory (including the development of one’s own). We believe that this recommendation represents a significant and constructive step forward. Our reflections on a number of the issues raised by those who wrote reactions to our article are below

Northern Bobwhite Population Structure and Diversity in Texas and the Great Plains

Many northern bobwhite (Colinus virginianus) populations have been experiencing severe declines. This decline is of concern to wildlife biologists, landowners, and legislators due to the popularity of this species as a game bird. Previous molecular genetic analyses for populations inhabiting intact habitats in South Texas indicate the northern bobwhite population in this region is genetically diverse with low population structure. W[e] assessed whether landscape affects the population structure and diversity for northern bobwhite in Texas and the Great Plains. We extracted DNA from hunter-harvested northern bobwhites from 19 sites in South Texas from 2004 to 2010. We analyzed 7 microsatellites (Quail 5, 8, 9, 10, 11, 12, and 15). We used FST to measure genetic structure and AMOVA for genetic variation. We built 3 matrices to compare the genetic structure with the landscape. Geographic distances (km) between sample locations were ascertained using Google Earth. A matrix of barriers incorporated large water bodies and highways. We used the Biologist Ranking Information from the National Bobwhite Conservation Initiative for the third matrix to identify the number of different habitat patches a quail would need to cross from ranch to ranch. These matrices were compared to the genetic structure (pairwise FST), using Mantel tests with 10,000 permutations. We used partial Mantel tests to test the correlation of pairwise FST to combinations of distance and barriers, distance and habitat, and barriers and habitat. Overall FST was \u3c 0.01, suggesting low levels of population differentiation and AMOVA revealed most variation was within individuals. All Mantel tests had a positive correlation with genetic differentiation; however, barriers appear to be important factors for the observed genetic patterns

Genetic Diversity and Relatedness Within and Among Northern Bobwhite Coveys in South Texas

Although biologists have studied northern bobwhite (Colinus virginianus) genetic diversity and population structure, there is little known about the genetic diversity, structure, and relatedness of their winter coveys. Both flexible mating strategies and the fall shuffle may have implications for inbreeding and genetic diversity in northern bobwhite populations. Our goal was to determine genetic diversity and relatedness for coveys on a private ranch in Jim Hogg County in South Texas. During the 2010–2011 and 2011–2012 hunting seasons, 96 northern bobwhites were sampled from 29 coveys. We analyzed 11 northern bobwhite microsatellite DNA loci, measured genetic structure with an Analysis of Molecular Variance and FST, and determined an inbreeding coefficient (Fi). We determined Queller and Goodnight’s coefficients of relatedness (R) and then used a maximum-likelihood algorithm in COLONY to assign relationships (parent–offspring, full siblings, and half siblings). Most genetic variation (92%) was within coveys. The overall FST was 0.073, indicating moderate genetic structure among coveys. Relationship coefficients ranged from –0.82 to 1.00 but most of the bird pairs were unrelated (R = -0.004 ± 0.002 SE). In 2010–2011, COLONY assigned 130–149 half sibling, 1–4 full sibling, and 0–3 parent-offspring pairs (n = 2,887, 5 trials, probability \u3e0.99). Thirteen coveys (56%) had related individuals (n = 20 pairs). In 2011– 2012, COLONY assigned 5–10 half sibling and 1 full sibling pairs (n = 161). Two coveys (33%) had related individuals (2 pairs). The occurrence of relatives in different coveys suggests that the fall shuffle is effective at mixing families and the high half sibling count among coveys may suggest polygamy. These strategies may help northern bobwhite populations maintain moderate genetic diversity

Northern Bobwhite Home Range Sizes and Movements in South Texas

Northern bobwhites (Colinus virginianus) often have relatively small home ranges (1-km radius); however, occasional long-distance movements also have been recorded, which may help maintain connectivity and genetic diversity within and among populations. We quantified movements of radiocollared northern bobwhites on the King Ranch in South Texas, USA. For each bird we determined core area, home range (fixed kernel), mean movement rate, and maximum distance moved. We compared movements across age, gender, precipitation trends, and plant communities using Mann–Whitney U and Kruskal–Wallis tests. Almost half (44.7%) of the birds moved \u3e400 m (max. distance moved) and 46 (16%) moved \u3e1 km over the course of the study. Males had higher movement rates (juvenile x̄ = 54.9 m, SE = 1.77 m, n = 64; adult x̄ = 56.6 m, SE = 1.95 m, n = 65) than females (juvenile x̄ = 51.26 m, SE = 1.80 m, n = 102; adult x̄ = 48.14 m, SE = 1.49 m, n = 62; χ23,289 = 14.90, P = 0.02). Maximum distance moved was longer in dry years (609.8 ± 136.3 m) compared with normal or moist years (x̄ = 542.8 m, SE = 47.0 m; x̄ = 536.6 m, SE = 28.8 m, respectively, n = 293). Northern bobwhites moved farther in dry years, possibly to find cover and food. A small percentage made relatively long-distance movements (n = 18, 6%, \u3e1.6 km, max. 6.5 km). These rare movements may influence gene flow and genetic structure of northern bobwhite populations in South Texas

Improved Standardization of Type II-P Supernovae: Application to an Expanded Sample

In the epoch of precise and accurate cosmology, cross-confirmation using a variety of cosmographic methods is paramount to circumvent systematic uncertainties. Owing to progenitor histories and explosion physics differing from those of Type Ia SNe (SNe Ia), Type II-plateau supernovae (SNe II-P) are unlikely to be affected by evolution in the same way. Based on a new analysis of 17 SNe II-P, and on an improved methodology, we find that SNe II-P are good standardizable candles, almost comparable to SNe Ia. We derive a tight Hubble diagram with a dispersion of 10% in distance, using the simple correlation between luminosity and photospheric velocity introduced by Hamuy & Pinto 2002. We show that the descendent method of Nugent et al. 2006 can be further simplified and that the correction for dust extinction has low statistical impact. We find that our SN sample favors, on average, a very steep dust law with total to selective extinction R_V<2. Such an extinction law has been recently inferred for many SNe Ia. Our results indicate that a distance measurement can be obtained with a single spectrum of a SN II-P during the plateau phase combined with sparse photometric measurements.Comment: ApJ accepted version. Minor change