Aquatic Invertebrate Community Structure, Biological Condition, Habitat, and Water Quality at Ozark National Scenic Riverways, Missouri, 2005-2014

Ozark National Scenic Riverways (OZAR) was established to protect the corridor of the Current River and its major tributary, the Jacks Fork. The Current River is one of the few remaining free-flowing rivers in the U.S., with much of its base flow coming from several large springs. To assess the biological condition of these rivers, aquatic invertebrate community structure was monitored from 2005 to 2014. Benthic invertebrate samples and associated habitat and water quality data were collected from each of nine sampling sites using a Slack-Surber sampler. The Stream Condition Index (SCI), a multimetric index that incorporates taxa richness, EPT (Ephemeroptera, Plecoptera, Trichoptera) richness, Shannon’s diversity index, and Hilsenhoff Biotic Index (HBI), was calculated. The benthic invertebrate fauna was diverse with 155 distinct taxa identified from all sites. Mean taxa richness was high, ranging from 22 to 30 among sites. The invertebrate taxa of the Current River and Jacks Fork are largely intolerant across all taxa represented (mean tolerance value= ~4.25). Mean HBI did not exceed 3.9 in the Current River or 4.4 for the Jacks Fork. Mean SCI scores across sampling sites generally were well above 16, indicating they are not impaired. Habitat and water quality data were summarized, but they were poorly correlated with individual invertebrate metrics. Sørenson’s similarity index was used to assess community similarity among sites, and similarity scores were then analyzed using ascendant hierarchical cluster analysis. Similarity among sites was 72% or greater. Cluster analysis showed that Current River and Jacks Fork sites clustered separately and in a downstream progression. The uppermost collection site on the Current River was most unlike the other sites, which probably relates to the distinct physical features of that site compared to the others. Nonmetric Multidimensional Scaling (NMDS) was used to evaluate the relationship of invertebrate metrics to habitat and water quality. The NMDS model was found to be a good fit (stress=0.04) and specific conductance, temperature, discharge, filamentous algae and aquatic vegetation were among the most important habitat variables in defining the relationship among sampling sites. The three lower Current River and Jacks Fork sites each were closely grouped in ordination space, but the three upper Current River sites were farther apart from each other. The influence of several large volume springs near those sites is suspected of producing such disparity through press type disturbances. Although the invertebrate communities and water quality in the Current River and Jacks Fork are largely sound and have high biological condition, ongoing and projected threats to these resources remain, and those threats largely originate outside park jurisdictional boundaries. Inherent variability of invertebrate community diversity across sites and years highlights the importance of using multi-metric assessments and multiyear monitoring to support management decisions

The Moment of Inertia of the Binary Pulsar J0737-3039A: Constraining the Nuclear Equation of State

We construct numerical models of the newly discovered binary pulsar J0737-3039A, both with a fully relativistic, uniformly rotating, equilibrium code that handles arbitrary spins and in the relativistic, slow-rotation approximation. We compare results for a representative sample of viable nuclear equations of state (EOS) that span three, qualitatively different, classes of models for the description of nuclear matter. A future dynamical measurement of the neutron star's moment of inertia from pulsar timing data will impose significant constraints on the nuclear EOS. Even a moderately accurate measurement (<~ 10 %) may be able to rule out some of these competing classes. Using the measured mass, spin and moment of inertia to identify the optimal model computed from different EOSs, one can determine the pulsar's radius.Comment: 4 pages, ApJL in pres

Principles of Chemotherapy and Their Application to the Management of Lymphosarcoma

Most repons of treatment of lymphosarcoma (LSA) in domestic animals have involved canine and feline LSA. The disease in cats differs from that in dogs in that feline LSA is caused by a contagious retrovirus. Controversy has existed as to whether feline leukemia virus (FeLV) positive cats with LSA should be treated because of their danger to other cats, or because of the controversial question of a human health hazard. There has been no proven danger to people, and 30% of cats with LSA are FeLV negative. Some owners elect chemotherapy for their cats regardless of potential risks. As a result of this increasing awareness of pet owners to the potential benefits to be gained by chemotherapy, the practicing veterinarian must be able to skillfully administer chemotherapy to pets who have developed cancer

Mode signature and stability for a Hamiltonian model of electron temperature gradient turbulence

Stability properties and mode signature for equilibria of a model of electron temperature gradient (ETG) driven turbulence are investigated by Hamiltonian techniques. After deriving the infinite families of Casimir invariants, associated with the noncanonical Poisson bracket of the model, a sufficient condition for stability is obtained by means of the Energy-Casimir method. Mode signature is then investigated for linear motions about homogeneous equilibria. Depending on the sign of the equilibrium "translated" pressure gradient, stable equilibria can either be energy stable, i.e.\ possess definite linearized perturbation energy (Hamiltonian), or spectrally stable with the existence of negative energy modes (NEMs). The ETG instability is then shown to arise through a Kre\u{\i}n-type bifurcation, due to the merging of a positive and a negative energy mode, corresponding to two modified drift waves admitted by the system. The Hamiltonian of the linearized system is then explicitly transformed into normal form, which unambiguously defines mode signature. In particular, the fast mode turns out to always be a positive energy mode (PEM), whereas the energy of the slow mode can have either positive or negative sign

Atomistic Theory of Coherent Spin Transfer between Molecularly Bridged Quantum Dots

Time-resolved Faradary rotation experiments have demonstrated coherent transfer of electron spin between CdSe colloidal quantum dots coupled by conjugated molecules. We employ here a Green's function approach, using semi-empirical tight-binding to treat the nanocrystal Hamiltonian and Extended Huckel theory to treat the linking molecule Hamiltonian, to obtain the coherent transfer probabilities from atomistic calculations, without the introduction of any new parameters. Calculations on 1,4-dithiolbenzene and 1,4-dithiolcyclohexane linked nanocrystals agree qualitatively with experiment and provide support for a previous transfer Hamiltonian model. We find a striking dependence on the transfer probabilities as a function of nanocrystal surface site attachment and linking molecule conformation. Additionally, we predict quantum interference effects in the coherent transfer probabilities for 2,7-dithiolnaphthalene and 2,6-dithiolnaphthalene linking molecules. We suggest possible experiments based on these results that would test the coherent, through-molecule transfer mechanism.Comment: 12 pages, 9 figures. Submitted Phys. Rev.

Wood Creek Tidal Marsh Enhancement Project Benthic Macroinvertebrate Monitoring Report 2019

The focus of this report was to monitor benthic macroinvertebrate communities on the Freshwater Farms Reserve, which underwent two phases of restoration as part of the Wood Creek Tidal Marsh Enhancement Project in 2009-2010 and 2016-2018. Objectives for the restoration activities were to increase winter rearing refugia habitat for several threatened/endangered fish species such as the tidewater goby (Eucyclogobius newberryi), Coho salmon (Oncorhynchus kisutch) and steelhead trout (Oncorhynchus mykiss). The goals of this project were to (1) sample and identify BMIs along a salinity gradient in Wood Creek; (2) assess water quality; and (3) report general trajectory of community composition over time. Results show that the abundance of benthic macroinvertebrates increased dramatically in Wood Creek in 2019 for all sampled sites when compared to previous years of monitoring data. Three taxa accounted for over 99% of the overall composition at each of the sample sites. Increased abundance of benthic macroinvertebrates may provide additional nutritional support for fish present in Wood Creek and Freshwater Creek. Overall, Freshwater Farms Reserve’s post-restoration ecological trajectory seems to be improving in relation to the goals of supporting fish refugia for threatened/endangered species