89 research outputs found

    Assessing the Efficacy of Beaver Dam Analogues in Willow Restoration

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    Assessing the Efficacy of Beaver Dam Analogues in Willow Restoration Undergraduate Capstone, Ecosystem Science and Restoration Program By Hannah Hill & Dylan Ritter Abstract Willow establishment is a necessary objective of stream restoration due to their role in bank stabilization, stream shading, and enhancement of biodiversity across the riparian zone. However, anecdotal observation indicated that establishment on restored streams may be lacking. For example, we observed no natural willow recruitment at a beaver dam analogs (BDAs) restoration project in Lolo National Forest (Montana). BDA’s mimic the pooling effects of natural beaver structures and are intended to help recreate historic conditions that existed before beaver extirpation. When working as intended, ecosystem function is restored, and a major aspect of this is willow presence. Because of these observations, as well as limited information specifically on willow recruitment following restoration, we ask the following questions. First, after BDA restoration, what is the rate of willow recruitment? And, what is the abundance of willows in these restored sites? Finally, to what extent do the environmental factors of water access, soil compaction, and abundance of competitor species impact the recruitment of willow? To answer this, we measured the density of willow and collected environmental data across 6 sites. We found willow density to be lower than expected with densities ranging from 1.6 stems/m2 to less than 0.1 stems/m2. Root sprout presence was almost non-existent, aside from two study sites that had additional restoration treatments. Although the two sites with root sprouts cannot paint a full picture of the correlation between our measurements and density, it is clear that willow regeneration is limited, if not nonexistent, without further interference. These findings contribute insight into the factors influencing willow recruitment and highlight a need to develop practices to improve willow establishment after restoration

    Assessing the Efficacy of Beaver Dam Analogs in Willow Restoration

    Get PDF
    Willow establishment is a necessary objective of stream restoration due to their role in bank stabilization, stream shading, and enhancement of biodiversity across the riparian zone. However, anecdotal observation indicated that establishment on beaver dam analogue (BDA) restored streams may be lacking. BDA’s mimic the pooling effects of natural beaver structures and are intended to help recreate historic conditions that existed before beaver extirpation. When working as intended, ecosystem function is restored, and a major aspect of this is willow presence. Because of these observations, as well as limited information on willow recruitment following restoration, we ask the following questions. First, after BDA restoration, what is the abundance of willows in these restored sites? And, what is the abundance of willow recruits? Finally, to what extent do the environmental factors of water access, soil compaction, and abundance of competitor species impact the recruitment of willow? To answer this, we measured the density of willow and collected environmental data across 6 sites. We found willow density to be lower than expected with densities ranging from 1.6 stems/m2 to less than 0.1 stems/m2. Root sprout presence was limited, aside from two study sites that had additional restoration treatments. Although the two sites with root sprouts cannot paint a full picture of the correlation between our measurements and recruitment density, it is clear that willow regeneration is limited, if not nonexistent, without further interference. These findings contribute insight into the factors influencing willow recruitment and highlight a need to develop practices to improve willow establishment after restoration

    The Juventas CubeSat in Support of ESA\u27s Hera Mission to the Asteroid Didymos

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    The European Space Agency’s planetary defense Hera mission will launch to the Didymos binary asteroid system in 2023 (with bodies nicknamed Didymain and Didymoon). Once in vicinity of the asteroid, two 6U CubeSats will be deployed to contribute to the asteroid research and mitigation assessment objectives of the Hera mission. This paperwill describe the Juventas CubeSat, equipped with a low frequency radar payload to characterize the internal structure of Didymoon. Juventas is designed to be operated using the Hera mothercraft as a proxy. This mission architecture creates a new paradigm for CubeSats, requiring high levels of mission autonomy while operating in the challenging environment of a small-body binary asteroid. Juventas will utilize the inter-satellite link to Hera for performing radio science experiments, augmenting the characterization of the asteroid gravity field. Once the radar science and radio science observation objectives have been met, Juventas will perform an attempted landing on the surface of Didymoon to research its dynamical properties

    Nitride tuning of lanthanide chromites

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    LnCrO3−xNx compounds with Ln = La, Pr and Nd represent one of the few examples of chromium oxynitrides and the first chromium oxynitride perovskites. Hole-doping of LnCrO3 through O2−/N3− anion substitution suppresses the antiferromagnetic transition far less drastically than cation substitutions.</p

    Nausea: Current knowledge of mechanisms, measurement and clinical impact

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    AbstractNausea is a subjective sensation, which often acts as a signal that emesis is imminent. It is a widespread problem that occurs as a clinical sign of disease or as an adverse effect of a drug therapy or surgical procedure. The mechanisms of nausea are complex and the neural pathways are currently poorly understood. This review summarises the current knowledge of nausea mechanisms, the available animal models for nausea research and the anti-nausea properties of commercially available anti-emetic drugs. The review also presents subjective assessment and scoring of nausea. A better understanding of the underlying mechanisms of nausea might reveal potential clinically useful biomarkers for objective measurement of nausea in species of veterinary interest

    Mu suppression – a good measure of the human mirror neuron system?

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    Mu suppression has been proposed as a signature of the activity of the human mirror neuron system. However the mu frequency band (8-13 Hz) overlaps with the alpha frequency band, which is sensitive to attentional fluctuation, and thus mu suppression could potentially be confounded by changes in attentional engagement. The specific baseline against which mu suppression is assessed may be crucial, yet there is little consistency in how this is defined. We examined mu suppression in 61 typical adults, the largest mu suppression study so far conducted. We compared different methods of baselining, and examined activity at central and occipital electrodes, to both biological (hands) and non-biological (kaleidoscope) moving stimuli, to investigate the involvement of attention and alpha activity in mu suppression. We also examined changes in beta power, another candidate index of mirror neuron system engagement. We observed strong mu suppression restricted to central electrodes when participants performed hand movements, demonstrating that mu is indeed responsive to the activity of the motor cortex. However, when we looked for a similar signature of mu suppression to passively observed stimuli, the baselining method proved to be crucial. Selective suppression for biological vs non-biological stimuli was seen at central electrodes only when we used a within-trial baseline based on a static stimulus: this method greatly reduced trial-by-trial variation in the suppression measure compared with baselines based on blank trials presented in separate blocks. Even in this optimal condition, 16-21% of participants showed no mu suppression. Changes in beta power also did not match our predicted pattern for mirror neuron system engagement, and did not seem to offer a better measure than mu. Our conclusions are in contrast to those of a recent meta-analysis, which concluded that mu suppression is a valid means to examine mirror neuron activity. We argue that mu suppression can be used to index the human mirror neuron system, but the effect is weak and unreliable and easily confounded with alpha suppression

    Taking firms to the stock market : IPOs and the importance of large banks in imperial Germany 1896-1913

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    Large universal banks played a major role for Germany?s industrialisation because they provided loans to the industry and thereby helped firms to overcome liquidity constraints. Previous research has also argued that they were equally important on the German stock market. The present paper provides quantitative and qualitative evidence that although the market for underwriters was dominated by a small oligopoly of six large banks, there was still perceptible competition, which kept fees and short run profits low. Another interesting finding of the paper is the absence of a signalling effect to investors. Neither underpricing nor the one year performance was different for the IPOs issued by one of the Big Six. Thus, although the German IPO business was in the hands of a small oligopoly, investors did not benefit from the lack of competition. One explanation is that the quality of IPOs on the German stock market of the time was very good in general caused by the competition between underwriters, but also by the tight regulation of underwriting, which ensured the quality of all firms on the German stock market

    Extrinsic Rewards and Intrinsic Motives: Standard and Behavioral Approaches to Agency and Labor Markets

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