Host‐specific morphologies but no host races in the commensal bivalve N eaeromya rugifera

Speciation by host shift is one of the explicit models of ecological speciation. A prerequisite of this model is the formation of host races (sympatric populations that show host‐specific genetic structuring and phenotypes). Many members of the diverse marine bivalve superfamily G aleommatoidea have obligate commensal relationships with invertebrate hosts. Some species have the ability to occupy multiple host species, thereby providing potential opportunities to test for the formation of host races. The N ortheast P acific galeommatoidean N eaeromya rugifera attaches to two strikingly different hosts: the blue mud shrimp U pogebia pugettensis and the polychaete sea mouse A phrodita spp. We tested if this host difference has resulted in the formation of host races using shell morphologies and genetic markers. We found that populations from different hosts differ significantly in shell morphology. However, based on mitochondrial makers, N . rugifera showed no distinct host‐specific genetic structuring, indicating the existence of a panmictic population. We conclude that the host‐specific morphologies these clams exhibit may reflect ecophenotypic plasticity rather than the existence of host races, but this needs to be corroborated with additional genetic data and larger sample sizes. The pronounced conchological variation within N . rugifera calls for further investigation of its taxonomic relationship with its poorly studied, but morphologically similar, sympatric congener N eaeromya compressa .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93718/1/ivb268.pd

Parallel experimental study of a novel super-thin thermal absorber based photovoltaic/thermal (PV/T) system against conventional photovoltaic (PV) system

Photovoltaic (PV) semiconductor degrades in performance due to temperature rise. A super thin-conductive thermal absorber is therefore developed to regulate the PV working temperature by retrofitting the existing PV panel into the photovoltaic/thermal (PV/T) panel. This article presented the parallel comparative investigation of the two different systems through both laboratory and field experiments. The laboratory evaluation consisted of one PV panel and one PV/T panel respectively while the overall field system involved 15 stand-alone PV panels and 15 retrofitted PV/T panels. The laboratory testing results demonstrated the PV/T panel could achieve the electrical efficiency of about 16.8% (relatively 5% improvement comparing with the stand-alone PV panel), and yield an extra amount of heat with thermal efficiency of nearly 65%. The field testing results indicated that the hybrid PV/T panel could enhance the electrical return of PV panels by nearly 3.5%, and increase the overall energy output by nearly 324.3%. Further opportunities and challenges were then discussed from aspects of different PV/T stakeholders to accelerate the development. It is expected that such technology could become a significant solution to yield more electricity, offset heating load freely and reduce carbon footprint in contemporary energy environment

Learning Motion Predictors for Smart Wheelchair using Autoregressive Sparse Gaussian Process

Constructing a smart wheelchair on a commercially available powered wheelchair (PWC) platform avoids a host of seating, mechanical design and reliability issues but requires methods of predicting and controlling the motion of a device never intended for robotics. Analog joystick inputs are subject to black-box transformations which may produce intuitive and adaptable motion control for human operators, but complicate robotic control approaches; furthermore, installation of standard axle mounted odometers on a commercial PWC is difficult. In this work, we present an integrated hardware and software system for predicting the motion of a commercial PWC platform that does not require any physical or electronic modification of the chair beyond plugging into an industry standard auxiliary input port. This system uses an RGB-D camera and an Arduino interface board to capture motion data, including visual odometry and joystick signals, via ROS communication. Future motion is predicted using an autoregressive sparse Gaussian process model. We evaluate the proposed system on real-world short-term path prediction experiments. Experimental results demonstrate the system's efficacy when compared to a baseline neural network model.Comment: The paper has been accepted to the International Conference on Robotics and Automation (ICRA2018

Evolutionary Diversification of the Marine Bivalve Clade Galeommatoidea.

This dissertation investigates the diversification and morphological evolution of a major extant marine invertebrate lineage - the bivalve superfamily Galeommatoidea. It is inspired by the increasing realization among macroevolutionary biologists that the interplay between abiotic and biotic factors has shaped global biodiversity through time and that biotic interactions cannot be ignored if we wish to reconcile theory with natural systems. Galeommatoidea is a particularly apt group for understanding the interactions between abitoic and biotic diversification drivers because it contains large numbers of obligate commensal as well as free-living species and is therefore amenable to comparative approaches. I examined the ecological and evolutionary patterns of free-living and commensal galeommatoidean species on three levels: 1) on a microevolutionary level, focusing on commensal species that occupy multiple hosts; 2) on a regional level, for a faunal assemblage of galeommatoidean taxa that span three well-defined biogeographic provinces in southern Australia; 3) on a global level, for the entire superfamily. My ecological synthesis (Ch.2) suggests that the free-living lifestyle is strongly correlated with living in hard-bottom habitats while the commensal lifestyle is an adaptation for living in sediments. Commensal associations with bioturbating hosts allow the small-bodied clams to attain refuges at depth from predation while remaining oxygenated through their hosts' bioturbation. A case study on Neaeromya rugifera (Ch.3) indicates that clam populations occupying different hosts differ significantly in shell morphologies, but do not show host-specific genetic structuring. Regional phylogeographic analyses of an endemic Australian galeommatoidean species (Ch.4) show that the interaction of the Middle Miocene Climate Transition with the specific geography of the southern coastline of Australia was the primary cladogenic driver in this group. Macroevolutionary study of Galeommatoidea (Ch.5) reveals that a major free-living clade exhibits higher rates of lineage diversification compared to the commensals, possibly driven by complex ecological interactions in coral reef ecosystems. However, commensal species exhibit higher morphological disparity and intercladal convergence, likely reflecting host-specific morphological adaptations. Taken together, my multi-level study demonstrates that the present diversity of Galeommatoidea is shaped by the inseparable interactions between abiotic and biotic factors.PHDEcology and Evolutionary BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/109049/1/jingchun_1.pd

Block-Randomized Stochastic Methods for Tensor Ring Decomposition

Tensor ring (TR) decomposition is a simple but effective tensor network for analyzing and interpreting latent patterns of tensors. In this work, we propose a doubly randomized optimization framework for computing TR decomposition. It can be regarded as a sensible mix of randomized block coordinate descent and stochastic gradient descent, and hence functions in a double-random manner and can achieve lightweight updates and a small memory footprint. Further, to improve the convergence, especially for ill-conditioned problems, we propose a scaled version of the framework that can be viewed as an adaptive preconditioned or diagonally-scaled variant. Four different probability distributions for selecting the mini-batch and the adaptive strategy for determining the step size are also provided. Finally, we present the theoretical properties and numerical performance for our proposals

Triton's trident: cryptic Neogene divergences in a marine clam ( L asaea australis ) correspond to A ustralia's three temperate biogeographic provinces

The southern coast of Australia is composed of three distinct biogeographic provinces distinguished primarily by intertidal community composition. Several ecological mechanisms have been proposed to explain their formation and persistence, but no consensus has been reached. The marine clam L asaea australis is arguably the most common bivalve on southern A ustralian rocky shores and occurs in all three provinces. Here, we tested if this species exhibits cryptic genetic structuring corresponding to the provinces and if so, what mechanisms potentially drove its divergence. Variation in two mitochondrial genes (16S and COIII ) and one nuclear gene ( ITS 2) was assayed to test for genetic structuring and to reconstruct the clam's phylogenetic history. Our results showed that L. australis is comprised of three cryptic mitochondrial clades, each corresponding almost perfectly to one of the three biogeographic provinces. Divergence time estimates place their cladogenesis in the Neogene. The trident‐like topology and Neogene time frame of L. australis cladogenesis are incongruent with Quaternary vicariance predictions: a two‐clade topology produced by Pleistocene Bass Strait land bridge formation. We hypothesize that the interaction of the Middle Miocene Climate Transition with the specific geography of the southern coastline of Australia was the primary cladogenic driver in this clam lineage. Additional in‐depth studies of the endemic southern Australian marine biota across all three provinces are needed to establish the generality of this proposed older framework for regional cladogenesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97297/1/mec12220.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97297/2/mec12220-sup-0002-FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/97297/3/mec12220-sup-0001-FigS1.pd

Stasis of functionally versatile specialists

A classic hypothesis posits that lineages exhibiting long‐term stasis are broadly adapted generalists that remain well‐adapted despite environmental change. However, lacking constraints that steepen adaptive peaks and stabilize the optimum, generalists’ phenotypes might drift around a broad adaptive plateau. We propose that stasis would be likely for morphological specialists that behave as ecological generalists much of the time because specialists’ functional constraints stabilize the optimum, but those with a broad niche, such as generalists, can persist despite environmental change. Tree squirrels (Callosciurinae and Sciurini) exemplify ecologically versatile specialists, being extreme in adaptations for forceful biting that expand rather than limit niche breadth. Here, we examine the structure of disparity and the evolutionary dynamics of their trophic morphology (mandible size and shape) to determine if they exhibit stasis. In both lineages, a few dietary specialists disproportionately account for disparity; excluding them, we find compelling evidence for stasis of jaw shape but not size. The primary optima of these lineages diverge little, if at all over approximately 30 million years. Once their trophic apparatus was assembled, their morphological specialization steepened the slopes of their adaptive peak and constrained the position of the optima without limiting niche breadth.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156132/2/evo13956.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156132/1/evo13956_am.pd

Visualization and Feature Extraction of the Surface Morphology of the Abdomen of Red Swamp Crayfish

This paper demonstrates a method for visual reconstruction and feature analysis of the surface morphology of red swamp crayfish in CATIA (Computer Aided Three Dimensional Interactive Application) and Microsoft Excel. Red swamp crayfish, Procambarus clarkii, with efficient burrowing activities and coupling propel pattern of abdomen with tail, was selected to study the feasible methods in the visual reconstruction and feature analysis of the surface morphology of living things. The digital measurements of surface of the red swamp crayfish were carried out using a three-dimensional laser scanner. Point clouds, the scanning digital data of the surface of the red swamp crayfish, were processed by deleting unwanted data, reconstructing surface in CATIA. There was a perfectly shape character similarity between the digital picture of the abdomen with corresponding point clouds shown in CATIA, and transverse curves which shown the surface morphology of abdomen in the cross section along the red swamp crayfish were obtained and saved as files of ASCII format in CATIA. Feature analysis of the abdomen of red swamp crayfish were carried out after files of single transverse curve were imported into Microsoft Excel, results shown that, the first row in file of single transverse curve was the number of rows after it, and those other rows stored coordinate values of measured points of the abdomen in the preset three-dimensional coordinate system, shapes of the abdomen in different cross sections were similar, and quadratic polynomial regression equation was able to effectively express surface morphology of the abdomen of red swamp crayfish. Methods and results presented in this paper prove to be potentially useful for analyzing the feature of biological prototype, optimizing the mathematical model and affording deformable physical model to bionic engineering, those works would have great implications to the research of biological coupling theory and technological creation in bionic engineering.Key words: Visual reconstruction; Feature analysis; Surface morphology; Red swamp crayfis