Brief Note: New Locality Records of the Longnose Dace Rhinichthys cataractae (Cyprinidae), in the Upper Ohio River Valley

Author Institution: Ohio Department of Natural Resources, Division of Natural Areas and Preserves ; Ohio Department of Transportation, Bureau of Environmental Service

Galaxy interactions in IllustrisTNG-100, I: The power and limitations of visual identification

We present a sample of 446 galaxy pairs constructed using the cosmological simulation IllustrisTNG-100 at z = 0, with M_(FoF,dm)=10¹¹−10^(13.5) M⊙. We produce ideal mock SDSS g-band images of all pairs to test the reliability of visual classification schema employed to produce samples of interacting galaxies. We visually classify each image as interacting or not based on the presence of a close neighbour, the presence of stellar debris fields, disturbed discs, and/or tidal features. By inspecting the trajectories of the pairs, we determine that these indicators correctly identify interacting galaxies ∼45 per cent of the time. We subsequently split the sample into the visually identified interacting pairs (VIP; 38 pairs) and those which are interacting but are not visually identified (nonVIP; 47 pairs). We find that VIP have undergone a close passage nearly twice as recently as the non-VIP, and typically have higher stellar masses. Further, the VIP sit in dark matter haloes that are approximately 2.5 times as massive, in environments nearly 2 times as dense, and are almost a factor of 10 more affected by the tidal forces of their surroundings than the nonVIP. These factors conspire to increase the observability of tidal features and disturbed morphologies, making the VIP more likely to be identified. Thus, merger rate calculations which rely on stellar morphologies are likely to be significantly biased toward massive galaxy pairs which have recently undergone a close passage

Human Apprenticeship Learning via Kernel-based Inverse Reinforcement Learning

It has been well demonstrated that inverse reinforcement learning (IRL) is an effective technique for teaching machines to perform tasks at human skill levels given human demonstrations (i.e., human to machine apprenticeship learning). This paper seeks to show that a similar application can be demonstrated with human learners. That is, given demonstrations from human experts inverse reinforcement learning techniques can be used to teach other humans to perform at higher skill levels (i.e., human to human apprenticeship learning). To show this two experiments were conducted using a simple, real-time web game where players were asked to touch targets in order to earn as many points as possible. For the experiment player performance was defined as the number of targets a player touched, irrespective of the points that a player actually earned. This allowed for in-game points to be modified and the effect of these alterations on performance measured. At no time were participants told the true performance metric. To determine the point modifications IRL was applied on demonstrations of human experts playing the game. The results of the experiment show with significance that performance improved over the control for select treatment groups. Finally, in addition to the experiment, we also detail the algorithmic challenges we faced when conducting the experiment and the techniques we used to overcome them.Comment: 31 pages, 23 figures, Submitted to Journal of Artificial Intelligence Research, "for source code, see https://github.com/mrucker/kpirl-kla

Spin-dynamics of the low-dimensional magnet (CH3)2NH2CuCl3

Dimethylammonium copper (II) chloride (also known as DMACuCl3 or MCCL) is a low dimensional S=1/2 quantum spin system proposed to be an alternating ferro-antiferromagnetic chain with similar magnitude ferromagnetic (FM) and antiferromagnetic (AFM) exchange interactions. Subsequently, it was shown that the existing bulk measurements could be adequately modeled by considering DMACuCl3 as independent AFM and FM dimer spin pairs. We present here new inelastic neutron scattering measurements of the spin-excitations in single crystals of DMACuCl3. These results show significant quasi-one-dimensional coupling, however the magnetic excitations do not propagate along the expected direction. We observe a band of excitations with a gap of 0.95 meV and a bandwidth of 0.82 meV.Comment: 3 pages, 2 figures included in text, submitted to proceedings of International Conference on Neutron Scattering, December 200

A proposed metric for assessing the measurement quality of individual microarrays

BACKGROUND: High-density microarray technology is increasingly applied to study gene expression levels on a large scale. Microarray experiments rely on several critical steps that may introduce error and uncertainty in analyses. These steps include mRNA sample extraction, amplification and labeling, hybridization, and scanning. In some cases this may be manifested as systematic spatial variation on the surface of microarray in which expression measurements within an individual array may vary as a function of geographic position on the array surface. RESULTS: We hypothesized that an index of the degree of spatiality of gene expression measurements associated with their physical geographic locations on an array could indicate the summary of the physical reliability of the microarray. We introduced a novel way to formulate this index using a statistical analysis tool. Our approach regressed gene expression intensity measurements on a polynomial response surface of the microarray's Cartesian coordinates. We demonstrated this method using a fixed model and presented results from real and simulated datasets. CONCLUSION: We demonstrated the potential of such a quantitative metric for assessing the reliability of individual arrays. Moreover, we showed that this procedure can be incorporated into laboratory practice as a means to set quality control specifications and as a tool to determine whether an array has sufficient quality to be retained in terms of spatial correlation of gene expression measurements

Powder metallurgy in Australasia

This article provides a concise overview of current powder metallurgy (PM) activities in Australia and important developments to date. The overview is concerned primarily with the conventional PM of titanium and titanium alloys. It also cites rapidly growing additive manufacturing (AM) activities in Australia. The article concludes with brief history, current activities, and future plans regarding PM titanium in New Zealand

Galaxy interactions in IllustrisTNG-100, I: The power and limitations of visual identification

We present a sample of 446 galaxy pairs constructed using the cosmological simulation IllustrisTNG-100 at z = 0, with M$_{FoF, dm}$ = 10$^{11}$-10$^{13.5}$ M$_{\odot}$. We produce ideal mock SDSS g-band images of all pairs to test the reliability of visual classification schema employed to produce samples of interacting galaxies. We visually classify each image as interacting or not based on the presence of a close neighbour, the presence of stellar debris fields, disturbed discs, and/or tidal features. By inspecting the trajectories of the pairs, we determine that these indicators correctly identify interacting galaxies $\sim45\%$ of the time. We subsequently split the sample into the visually identified interacting pairs (VIP; 38 pairs) and those which are interacting but are not visually identified (nonVIP; 47 pairs). We find that VIP have undergone a close passage nearly twice as recently as the nonVIP, and typically have higher stellar masses. Further, the VIP sit in dark matter haloes that are approximately 2.5 times as massive, in environments nearly 2 times as dense, and are almost a factor of 10 more affected by the tidal forces of their surroundings than the nonVIP. These factors conspire to increase the observability of tidal features and disturbed morphologies, making the VIP more likely to be identified. Thus, merger rate calculations which rely on stellar morphologies are likely to be significantly biased toward massive galaxy pairs which have recently undergone a close passage.Comment: 20 pages, 11 figures, thumbnail catalog of interacting pairs sampl

The Grand Tour of the Ruby-East Humboldt Metamorphic Core Complex, Northeastern Nevada: Part 1-Introduction & Road Log

The purpose of this geological excursion is to provide an overview of the multiphase developmental history of the Ruby Mountains and East Humboldt Range, northeastern Nevada. Although these mountain ranges are commonly cited as a classic example of a Cordilleran metamorphic core complex developed through large-magnitude, mid-Tertiary crustal extension, a preceding polyphase Mesozoic contractional history is also well preserved in the ranges. An early phase of this history involved Late Jurassic two-mica granitic magmatism, high-temperature but relatively low-pressure metamorphism, and polyphase deformation in the central Ruby Mountains. In the northern Ruby Mountains and East Humboldt Range, a Late Cretaceous history of crustal shortening, metamorphism, and magmatism is manifested by fold-nappes (involving Archean basement rocks in the northern East Humboldt Range), widespread migmatization, injection of monzogranitic and leucogranitic magmas, all coupled with sillimanite-grade metamorphism. Following Late Cretaceous contraction, a protracted extensional deformation partially overprinted these areas during the Cenozoic. This extensional history may have begun as early as the Late Cretaceous or as late as the mid-Eocene. Late Eocene and Oligocene magmatism occurred at various levels in the crust yielding mafic to felsic orthogneisses in the deep crust, a composite granitic pluton in the upper crust, and volcanic rocks at the surface. Movement along a west-rooted, extensional shear zone in the Oligocene and early Miocene led to core-complex exhumation. The shear zone produced mylonitic rocks about 1 km thick at deep crustal levels, and an overprint of brittle detachment faulting at shallower levels as unroofing proceeded. Megabreccias and other synextensional sedimentary deposits are locally preserved in a tilted, upper Eocene through Miocene stratigraphic sequence. Neogene magmatism included the emplacement of basalt dikes and eruption of rhyolitic rocks. Subsequent Basin and Range normal faulting, as young as Holocene, records continued tectonic extension