Real closed fields with nonstandard and standard analytic structure

We consider the ordered field which is the completion of the Puiseux series field over \bR equipped with a ring of analytic functions on [-1,1]^n which contains the standard subanalytic functions as well as functions given by t-adically convergent power series, thus combining the analytic structures from [DD] and [LR3]. We prove quantifier elimination and o-minimality in the corresponding language. We extend these constructions and results to rank n ordered fields \bR_n (the maximal completions of iterated Puiseux series fields). We generalize the example of Hrushovski and Peterzil [HP] of a sentence which is not true in any o-minimal expansion of \bR (shown in [LR3] to be true in an o-minimal expansion of the Puiseux series field) to a tower of examples of sentences \sigma_n, true in \bR_n, but not true in any o-minimal expansion of any of the fields \bR,\bR_1,...,\bR_{n-1}.Comment: 15 pages, no figure

GENETIC MONITORING AND RESCUE IN MID-ATLANTIC BROOK TROUT (SALVELINUS FONTINALIS) POULATIONS

Brook trout (Salvelinus fontinalis) populations have experienced dramatic declines throughout their native range, in part, due to anthropogenic land use and habitat fragmentation. In the mid-Atlantic region, brook trout populations often occupy small, headwater habitat fragments in demographic and genetic isolation, making them vulnerable to inbreeding and genetic drift. My dissertation evaluates different methods for genetic assessment, monitoring, and management of small, isolated brook trout populations. First, I examined the potential value of effective number of breeders (Nb) estimates for genetic monitoring by determining whether Nb estimates were sensitive to habitat characteristics known to affect brook trout populations. Using genetic data from 71 brook trout habitat patches, I found significant evidence that Nb estimates were positively related to habitat size and base flow index, and negatively related to temperature. These results provide further support for the use of Nb in genetic assessments and monitoring of isolated salmonid populations. Human-mediated gene flow is a promising approach to reduce extinction risk and alleviate negative fitness effects associated with small effective population size (i.e., genetic rescue). However, there had not been an assessment of the statistical power of commonly used approaches to determine fitness effects of gene flow, despite calls for more widespread use of human-mediated gene flow. I addressed this need by using individual-based simulations of gene flow and found that these monitoring approaches frequently suffered from low statistical power but also identified strategies to improve inference. Finally, I examined the multigenerational effects of genetic rescue in a small, isolated population of brook trout and found consistent evidence of elevated fitness in F1 hybrids as compared to resident individuals. In contrast, I found a negative relationship between proportion migrant ancestry and lifetime reproductive success in backcrosses (F2 and later generations). Still, backcrosses with less than 0.48 migrant ancestry had lifetime reproductive success greater than residents, on average. These results highlight that gene flow often introduces beneficial and deleterious variation with the net-effect depending on the efficacy of natural selection, which suggests that ecological conditions affecting demography can play an outsized role in determining the outcome of genetic rescue attempts

When the Hot Stove Goes Cold: The TCJA, Baseball Contracts, and Avoiding an Administrative Nightmare

In 2017, Congress passed the Tax Cuts and Jobs Act, a sweeping tax reform bill which altered huge swaths of the Internal Revenue Code. Among the numerous changes was an alteration to § 1031 of the Code, which defers taxable gains for taxpayers exchanging property with other taxpayers for similar property; more specifically, the Act limited this section to real property

Experimental Test of Genetic Rescue in Isolated Populations of Brook Trout

Translocations are an important aspect of the management of natural populations in an increasingly fragmented landscape. Maintaining connectivity and gene flow is beneficial for both contemporary fitness and adaptive potential in the face of environmental change. Genetic rescue (GR) can alleviate inbreeding depression, genetic load, and increase adaptive potential of populations. Here, I have translocated 10 (5 of each sex) brook trout (Salvelinus fontinalis) to four geographically proximate and environmentally similar fragmented stream-dwelling populations of brook trout in Virginia to test for genetic rescue. The translocated brook trout contributed to more families than would be expected under neutral introgression, and hybridization resulted consistently in larger full-sibling family sizes. In the cohort immediately following translocation I observed relatively high (\u3e20%) introgression in 3 of the 4 recipient sites, and in one recipient population 57.7 % of the offspring had at least one migrant parent. During the post-translocation period favorable regional climatic conditions resulted in large cohorts across recipient sites and controls, however the percent increase in juvenile abundance scales to initial genetic diversity and patch size. I observe strong evidence of hybrid vigor through consistently larger body sizes of hybrid offspring. At this point I cannot rule out potential negative effects of translocations such as outbreeding depression with out sampling more cohorts following genetic recombination. However, I provide an empirical and replicated foundation to begin assessing the efficacy of GR-motivated translocations for headwater fish conservation, and make a substantial contribution to the growing body of GR-literature

Waterproofing 3D-Printed Parts

Team Operation: Watertight has been given the task to design a technique for printing or a post process application for treating fused deposition modeled parts to become impermeable to water. The final design report shows the progress made over the past academic year in order to create this process. In the fall, the team brainstormed many possible solutions and was able to narrow them down with the support of our sponsors, accompanied by a lot of research. This research consisted of many literature searches and patent searches to ensure there was not a process already designed for this application. Last semester, four concepts were selected and tested: resin injection, resin vacuum in filtration, XTC-3D, and Gelcoat. Each concept was applied to 3D printed ABS parts and then submerged in water. The change in mass after submersion for varying lengths of time allowed for the evaluation of each process. From the results seen, XTC-3D and resin injection proved to be the most promising out of the four. With this knowledge, the two methods were combined and tested in the Spring semester. They were not only tested by submergence, but pressure and strength tests were done as well. The original goal for the pressure test was to create a vessel to withstand 100 psi. With the methods applied, this goal was surpassed by 200 psi. The strength test was completed to see the effects of each method on the structural integrity of the 3D printed part

Tuning Nanocrystal Surface Depletion by Controlling Dopant Distribution as a Route Toward Enhanced Film Conductivity

Electron conduction through bare metal oxide nanocrystal (NC) films is hindered by surface depletion regions resulting from the presence of surface states. We control the radial dopant distribution in tin-doped indium oxide (ITO) NCs as a means to manipulate the NC depletion width. We find in films of ITO NCs of equal overall dopant concentration that those with dopant-enriched surfaces show decreased depletion width and increased conductivity. Variable temperature conductivity data shows electron localization length increases and associated depletion width decreases monotonically with increased density of dopants near the NC surface. We calculate band profiles for NCs of differing radial dopant distributions and, in agreement with variable temperature conductivity fits, find NCs with dopant-enriched surfaces have narrower depletion widths and longer localization lengths than those with dopant-enriched cores. Following amelioration of NC surface depletion by atomic layer deposition of alumina, all films of equal overall dopant concentration have similar conductivity. Variable temperature conductivity measurements on alumina-capped films indicate all films behave as granular metals. Herein, we conclude that dopant-enriched surfaces decrease the near-surface depletion region, which directly increases the electron localization length and conductivity of NC films