180 research outputs found
Impacts of Man-Made Structures on Avian Community Metrics in 4 State Parks in Northwestern Arkansas
Avian community metrics often differ between areas with no human disturbance and areas with high levels of human disturbance. However, the relationships between avian community metrics and smaller-scale disturbances are not as clear. Our goal was to investigate if avian abundance, richness, evenness, and diversity differed in areas with and without small-scale human developments. We used fixed-radius 50-m avian point counts to compare points which contained a man-made structure (n = 47), such as a picnic area, road, or campsite to those that did not contain a man-made structure (n = 181) at 4 state parks in Arkansas during 18 May â 7 August 2015. We used paired t-tests to compare points at the park scale and one-way ANOVAs or Kruskal-Wallis tests to investigate differences among the hiking and biking trails within parks. At the park scale, avian abundance (tâ = -1.44, P = 0.246), richness (tâ = Ë0.86, P = 0.453), diversity (tâ= 2.02, P = 0.137), and evenness (tâ =Ë0.37, P = 0.733) did not differ between points containing man-made structures and points without man-made structures. Species richness (F1,11 = 5.03, P= 0.047) and diversity (X^2â = 4.20, P = 0.040) were higher at points with man-made structures (Simpsonâs D mean = 0.13 ± 0.01SE; S mean = 8.99 ± 0.70SE) at Pinnacle Mountain than points without man-made structures (Simpsonâs D mean = 0.18 ± 0.03SE; S mean = 7.17 ± 0.47SE); abundance (Fâ, ââ = 1.43, P =0.257) and evenness (Fâ, ââ = 0.16, P = 0.695) did not differ among points. Within the 3 remaining parks, abundance (Fâ,7-9 = 0.11 â 2.59, P = 0.152 â 0.748), richness (Ï^2 â = 0.300 â 1.68, P = 0.195 â 0.584), diversity (Ï2 = 0.300 â 1.05, P = 0.305 â 0.584; Fâ,7 =1.82, P = 0.219) and evenness (Fâ,7-9 = 0.35 â 4.28, P =0.077 â 0.570) did not differ between points with and without man-made structures. Given the results of our analyses both at the park scale and within parks, it appears that small-scale man-made disturbances may have limited or no impact on avian community metrics
Attributes Preferred and Premiums Offered for Naturally Produced Beef Cattle
A growing number of beef cattle producers in the US are using limited information to determine whether or not it would be economical for them to grow naturally produced cattle. The objective was to discover the attributes that marketing companies prefer for the naturally produced cattle they purchase, and to elicit the price premiums being offered for cattle that possess these attributes. Results of a phone survey of companies that purchase natural cattle show that 27 out of 32 companies report their willingness to pay a premium of $5.95/cwt for cattle that have never received antibiotics, ionophores, hormones or animal by-products.Key words: attributes, beef, cattle, naturally produced, premiums, Agribusiness, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries, Marketing,
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Diffusion-Based smoothers for spatial filtering of gridded geophysical data
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Grooms, I., Loose, N., Abernathey, R., Steinberg, J. M., Bachman, S. D., Marques, G., Guillaumin, A. P., & Yankovsky, E. Diffusion-Based smoothers for spatial filtering of gridded geophysical data. Journal of Advances in Modeling Earth Systems, 13(9), (2021): e2021MS002552, https://doi.org/10.1029/2021MS002552.We describe a new way to apply a spatial filter to gridded data from models or observations, focusing on low-pass filters. The new method is analogous to smoothing via diffusion, and its implementation requires only a discrete Laplacian operator appropriate to the data. The new method can approximate arbitrary filter shapes, including Gaussian filters, and can be extended to spatially varying and anisotropic filters. The new diffusion-based smoother's properties are illustrated with examples from ocean model data and ocean observational products. An open-source Python package implementing this algorithm, called gcm-filters, is currently under development.I.G. and N.L. are supported by NSF OCE 1912332. R.A. is supported by NSF OCE 1912325. J.S. is supported by NSF OCE 1912302. S.B. and G.M. are supported by NSF OCE 1912420. A.G. and E.Y. are supported by NSF GEO 1912357 and NOAA CVP NA19OAR4310364
Realâtime biofeedback integrated into neuromuscular training reduces highârisk knee biomechanics and increases functional brain connectivity: A preliminary longitudinal investigation
Prospective evidence indicates that functional biomechanics and brain connectivity may predispose an athlete to an anterior cruciate ligament injury, revealing novel neural linkages for targeted neuromuscular training interventions. The purpose of this study was to determine the efficacy of a realâtime biofeedback system for altering knee biomechanics and brain functional connectivity. Seventeen healthy, young, physically active female athletes completed 6 weeks of augmented neuromuscular training (aNMT) utilizing realâtime, interactive visual biofeedback and 13 served as untrained controls. A drop vertical jump and resting state functional magnetic resonance imaging were separately completed at preâ and posttest time points to assess sensorimotor adaptation. The aNMT group had a significant reduction in peak knee abduction moment (pKAM) compared to controls (p = .03, d = 0.71). The aNMT group also exhibited a significant increase in functional connectivity between the right supplementary motor area and the left thalamus (p = .0473 after false discovery rate correction). Greater percent change in pKAM was also related to increased connectivity between the right cerebellum and right thalamus for the aNMT group (p = .0292 after false discovery rate correction, r2 = .62). No significant changes were observed for the controls (ps > .05). Our data provide preliminary evidence of potential neural mechanisms for aNMTâinduced motor adaptations that reduce injury risk. Future research is warranted to understand the role of neuromuscular training alone and how each component of aNMT influences biomechanics and functional connectivity.Emergent evidence indicates that the risk of anterior cruciate ligament (ACL) injury is, in part, due to central nervous system alterations that could be targeted using neural mechanistic sensorimotorâbased treatments. Young female athletes completed 6 weeks of neuromuscular training while interacting with a realâtime, visual biofeedback stimulus. Our training was designed to reduce the risk of by (a) promoting injuryâresistant movement and (b) strengthening brain functional connectivity. Our data not only indicated that athletesâ biomechanics and brain connectivity were improved following training, but the observed biomechanical improvements were related to distinct, strengthened connectivity within regions important for sensorimotor control. This study supports the use of realâtime biofeedback systems to reduce the risk of ACL injury by leveraging neuroplasticity.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154933/1/psyp13545_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154933/2/psyp13545.pd
Relating Coral Skeletal Structures at Different Length Scales to Growth, Light Availability to Symbiodinium, and Thermal Bleaching
Light scattering of coral skeletons and tissues increases light availability to photosynthetic endosymbionts to form one of the most efficient biological collectors of solar radiation. Rapid increases in light availability during thermally-induced symbiont loss (bleaching) impair photosynthetic performance of the remaining Symbiodinium and precipitate a more severe bleaching response (optical feedback-loop hypothesis). Here we focus on light scattering of the skeleton, which is determined by light interaction with skeletal components assembled in a hierarchical fractal-like structure from tens of nanometers (e.g., calcium carbonate nanograins) to micro- and milli-meters (septa, corallites, and coenosteum) to centimeters and higher (colony form). We examined the association between skeletal structures, their role in light scattering, and species-specific bleaching responses for 88 coral species using phylogenetically-corrected analysis. We also explored the effect of growth on light scattering by modeling the fractal-like accretive growth of the skeleton (assuming a diffusion limited process of biomineralization) as a function of skeletal density, size of nanograins, fractal range of biomineralized clusters, and overall mass-fractal dimension, and validated the model with experimental data. Our results show that differences in light scattering from the top ~200 ÎŒm (micro-ÎŒsâČ) of the skeleton, and not from the whole skeleton (bulk-ÎŒsâČ), are related to bleaching susceptibility. We also demonstrate how differences in micro-ÎŒsâČ of corallites and coenosteum could explain, in part, the heterogeneous light environment between polyp and coenosarc. The average effective light transport distance of coenosteum measured in 14 coral species indicates that coenosteum could transport light to the corallites, which could then function as âlight-trapping devicesâ where photons are scattered multiple times by septa and corallite walls until absorbed by Symbiodinium. Furthermore, our fractal skeletal growth model suggests that corals that grow faster typically have lower mass-fractal dimension, denser skeletons, lower skeletal micro-ÎŒsâČ, and higher bleaching susceptibility. Finally, our results demonstrate that several skeletal structures of varying length scales known to modulate the light microenvironment of Symbiodinium in coral tissue are not associated with bleaching susceptibility. This work provides evidence of the relationship between skeletal growth, light scattering, and bleaching, and further supports the optical feedback-loop hypothesis of coral bleaching
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Parameterizing the Impact of Unresolved Temperature Variability on the Large-Scale Density Field: 2. Modeling
Ocean circulation models have systematic errors in large-scale horizontal density gradients due to estimating the grid-cell-mean density by applying the nonlinear seawater equation of state to the grid-cell-mean water properties. In frontal regions where unresolved subgrid-scale (SGS) fluctuations are significant, dynamically relevant errors in the representation of current systems can result. A previous study developed a novel and computationally efficient parameterization of the unresolved SGS temperature variance and resulting density correction. This parameterization was empirically validated but not tested in an ocean model. In this study, we implement deterministic and stochastic variants of this parameterization in the pressure-gradient force term of a coupled ocean-sea ice configuration of the community Earth system model-modular ocean model version 6 and perform a suite of hindcast sensitivity experiments to investigate the ocean response. The parameterization leads to coherent changes in the large-scale ocean circulation and hydrography, particularly in the Nordic Seas and Labrador Sea, which are attributable in large part to changes in the seasonally varying upper-ocean exchange through Denmark Strait. In addition, the separated Gulf Stream strengthens and shifts equatorward, reducing a common bias in coarse-resolution ocean models. The ocean response to the deterministic and stochastic variants of the parameterization is qualitatively, albeit not quantitatively, similar, yet qualitative differences are found in various regions.
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Bone Marrowâgenerated Dendritic Cells Pulsed with Tumor Extracts or Tumor RNA Induce Antitumor Immunity against Central Nervous System Tumors
Recent studies have shown that the brain is not a barrier to successful active immunotherapy that uses gene-modified autologous tumor cell vaccines. In this study, we compared the efficacy of two types of vaccines for the treatment of tumors within the central nervous system (CNS): dendritic cell (DC)-based vaccines pulsed with either tumor extract or tumor RNA, and cytokine geneâmodified tumor vaccines. Using the B16/F10 murine melanoma (B16) as a model for CNS tumor, we show that vaccination with bone marrowâgenerated DCs, pulsed with either B16 cell extract or B16 total RNA, can induce specific cytotoxic T lymphocytes against B16 tumor cells. Both types of DC vaccines were able to protect animals from tumors located in the CNS. DC-based vaccines also led to prolonged survival in mice with tumors placed before the initiation of vaccine therapy. The DC-based vaccines were at least as effective, if not more so, as vaccines containing B16 tumor cells in which the granulocytic macrophage colony-stimulating factor gene had been modified. These data support the use of DC-based vaccines for the treatment of patients with CNS tumors
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