6,157 research outputs found

    Clonal Dynamics and Evolution of Dormancy in the Leafy Hepatic "Lophozia silvicola" [Revised 10 September 2001]

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    Dead shoots of colonies of hepatic species "Lophozia silvicola" Buch are replaced by shoots developing from asexual propagules, the gemmae. Observations of two populations of "L. silvicola" showed a strong decreasing seasonal trend in germinability of the gemmae. We suggest that the non-germinating gemmae enter dormancy, and that the proportion of gemmae entering dormancy is season-specific. We assume that there are two types of gemmae, dormant and non-dormant and that only the dormant gemmae can survive during winter. Using a stochastic individual-based cellular automaton model, we investigated whether selection on season-specific dormancy fraction would lead to a decreasing proportion of germinating gemmae. Thus the germination schedule is the evolving trait in the model. Parameter estimates for the model were based on data collected from a population of "L. silvicola" on southern Finland over a three-year study period. In the simulations, the germination schedule shaped by evolutionary change was similar to the observed pattern. Thus the modeling results give support to the dormancy hypothesis. The qualitative pattern of decreasing germinability towards the end of the growing season is robust. Quantitative predictions are influenced by changes in parameters; for example, if winter mortality of shoots increases relative to mortality during the growing season, production of an increased fraction of dormant gemmae is favored, especially at the end of the season

    Digiwall - an audio mostly game

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    Presented at the 12th International Conference on Auditory Display (ICAD), London, UK, June 20-23, 2006.DigiWall is a hybrid between a climbing wall and a computer game. The climbing grips are equipped with touch sensors and lights. The interface has no computer screen. Instead sound and music are principle drivers of DigiWall interaction models. The gaming experience combines sound and music with physical movement and the sparse visuals of the climbing grips. The DigiWall soundscape carries both verbal and nonverbal information. Verbal information includes instructions on how to play a game, scores, level numbers etc. Non-verbal information is about speed, position, direction, events etc. Many different types of interaction models are possible: competitions, collaboration exercises and aesthetic experiences

    Experimental Identification of the Kink Instability as a Poloidal Flux Amplification Mechanism for Coaxial Gun Spheromak Formation

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    The magnetohydrodynamic kink instability is observed and identified experimentally as a poloidal flux amplification mechanism for coaxial gun spheromak formation. Plasmas in this experiment fall into three distinct regimes which depend on the peak gun current to magnetic flux ratio, with (I) low values resulting in a straight plasma column with helical magnetic field, (II) intermediate values leading to kinking of the column axis, and (III) high values leading immediately to a detached plasma. Onset of column kinking agrees quantitatively with the Kruskal-Shafranov limit, and the kink acts as a dynamo which converts toroidal to poloidal flux. Regime II clearly leads to both poloidal flux amplification and the development of a spheromak configuration.Comment: accepted for publication in Physical Review Letter

    Inelastic scattering of light by a cold trapped atom: Effects of the quantum center-of-mass motion

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    The light scattered by a cold trapped ion, which is in the stationary state of laser cooling, presents features due to the mechanical effects of atom-photon interaction. These features appear as additional peaks (sidebands) in the spectrum of resonance fluorescence. Among these sidebands the literature has discussed the Stokes and anti-Stokes components, namely the sidebands of the elastic peak. In this manuscript we show that the motion also gives rise to sidebands of the inelastic peaks. These are not always visible, but, as we show, can be measured in parameter regimes which are experimentally accessible.Comment: 10 pages, 4 figures, submitted to Phys. Rev.

    Peripheral volume measurements as indices of peripheral circulatory factors in the cardiovascular orthostatic response

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    Peripheral volume measurements as indices of circulatory factors in cardiovascular orthostatic respons

    Biofabrication Strategies for Musculoskeletal Disorders: Evolution towards Clinical Applications

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    Biofabrication has emerged as an attractive strategy to personalise medical care and provide new treatments for common organ damage or diseases. While it has made impactful headway in e.g., skin grafting, drug testing and cancer research purposes, its application to treat musculoskeletal tissue disorders in a clinical setting remains scarce. Albeit with several in vitro breakthroughs over the past decade, standard musculoskeletal treatments are still limited to palliative care or surgical interventions with limited long-term effects and biological functionality. To better understand this lack of translation, it is important to study connections between basic science challenges and developments with translational hurdles and evolving frameworks for this fully disruptive technology that is biofabrication. This review paper thus looks closely at the processing stage of biofabrication, specifically at the bioinks suitable for musculoskeletal tissue fabrication and their trends of usage. This includes underlying composite bioink strategies to address the shortfalls of sole biomaterials. We also review recent advances made to overcome long-standing challenges in the field of biofabrication, namely bioprinting of low-viscosity bioinks, controlled delivery of growth factors, and the fabrication of spatially graded biological and structural scaffolds to help biofabricate more clinically relevant constructs. We further explore the clinical application of biofabricated musculoskeletal structures, regulatory pathways, and challenges for clinical translation, while identifying the opportunities that currently lie closest to clinical translation. In this article, we consider the next era of biofabrication and the overarching challenges that need to be addressed to reach clinical relevance

    Byproduct-based concentrates in Swedish dairy cow diets - evaluation of environmental impact and feed costs

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    This study compared use of byproduct-based concentrates and a control feed based on cereal grains and soybean meal in dairy cow diets and evaluated effects on the environment and feed costs. To achieve a nutrient-dense feed ration to dairy cows byproducts are commonly combined with cereal grains and protein-rich feeds such as soybean meal. The present analysis was based on experimental data for high-yielding dairy cows showing that feeding concentrate based on byproducts gives similar milk yield as feeding concentrate based on cereal grains and soybean meal. Evaluation of the different concentrates using life cycle assessment showed that using byproducts required less cropland (-35%), reduced carbon footprint (-20%) and lowered eutrophication potential (-20%) compared with the control. Energy use was higher (+30%), due to the need for drying wet byproducts. Feed costs per kg energy-corrected milk did not differ between the feeds, which is beneficial from a sustainability perspective

    Urban energy exchanges monitoring from space

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    One important challenge facing the urbanization and global environmental change community is to understand the relation between urban form, energy use and carbon emissions. Missing from the current literature are scientific assessments that evaluate the impacts of different urban spatial units on energy fluxes; yet, this type of analysis is needed by urban planners, who recognize that local scale zoning affects energy consumption and local climate. However, satellite-based estimation of urban energy fluxes at neighbourhood scale is still a challenge. Here we show the potential of the current satellite missions to retrieve urban energy budget, supported by meteorological observations and evaluated by direct flux measurements. We found an agreement within 5% between satellite and in-situ derived net all-wave radiation; and identified that wall facet fraction and urban materials type are the most important parameters for estimating heat storage of the urban canopy. The satellite approaches were found to underestimate measured turbulent heat fluxes, with sensible heat flux being most sensitive to surface temperature variation (-64.1, +69.3 W m-2 for ±2 K perturbation); and also underestimate anthropogenic heat flux. However, reasonable spatial patterns are obtained for the latter allowing hot-spots to be identified, therefore supporting both urban planning and urban climate modelling

    Protein folding rates correlate with heterogeneity of folding mechanism

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    By observing trends in the folding kinetics of experimental 2-state proteins at their transition midpoints, and by observing trends in the barrier heights of numerous simulations of coarse grained, C-alpha model, Go proteins, we show that folding rates correlate with the degree of heterogeneity in the formation of native contacts. Statistically significant correlations are observed between folding rates and measures of heterogeneity inherent in the native topology, as well as between rates and the variance in the distribution of either experimentally measured or simulated phi-values.Comment: 11 pages, 3 figures, 1 tabl
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