1,712 research outputs found

    The Influence of Land Use and Climate Change on Forest Biomass and Composition in Massachusetts, USA

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    Land use and climate change have complex and interacting effects on naturally dynamic forest landscapes. To anticipate and adapt to these changes, it is necessary to understand their individual and aggregate impacts on forest growth and composition. We conducted a simulation experiment to evaluate regional forest change in Massachusetts, USA over the next 50 years (2010–2060). Our objective was to estimate, assuming a linear continuation of recent trends, the relative and interactive influence of continued growth and succession, climate change, forest conversion to developed uses, and timber harvest on live aboveground biomass (AGB) and tree species composition. We examined 20 years of land use records in relation to social and biophysical explanatory variables and used regression trees to create “probability-of-conversion” and “probability-of-harvest” zones. We incorporated this information into a spatially interactive forest landscape simulator to examine forest dynamics as they were affected by land use and climate change. We conducted simulations in a full-factorial design and found that continued forest growth and succession had the largest effect on AGB, increasing stores from 181.83 Tg to 309.56 Tg over 50 years. The increase varied from 49% to 112% depending on the ecoregion within the state. Compared to simulations with no climate or land use, forest conversion reduced gains in AGB by 23.18 Tg (or 18%) over 50 years. Timber harvests reduced gains in AGB by 5.23 Tg (4%). Climate change (temperature and precipitation) increased gains in AGB by 17.3 Tg (13.5%). Pinus strobus and Acer rubrum were ranked first and second, respectively, in terms of total AGB throughout all simulations. Climate change reinforced the dominance of those two species. Timber harvest reduced Quercus rubra from 10.8% to 9.4% of total AGB, but otherwise had little effect on composition. Forest conversion was generally indiscriminate in terms of species removal. Under the naïve assumption that future land use patterns will resemble the recent past, we conclude that continued forest growth and recovery will be the dominant mechanism driving forest dynamics over the next 50 years, and that while climate change may enhance growth rates, this will be more than offset by land use, primarily forest conversion to developed uses

    Reviewing two decades of energy system analysis with bibliometrics

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    Acknowledgements Dominik Franjo Dominkovi®c was funded by the CITIES project nr. DSF1305-00027B and Cool-Data project nr. 0177-00066B, both funded by the Danish Innovationsfonden. Fabian Scheller kindly acknowledges the financial support of the European Union’s research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 713683 (COFUNDfellowsDTU). The authors also thank three anonymous reviewers for their helpful comments on an earlier version of this paper. The usual disclaimer applies.Peer reviewedPostprin

    Reviewing two decades of energy system analysis with bibliometrics

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    Acknowledgements Dominik Franjo Dominkovi®c was funded by the CITIES project nr. DSF1305-00027B and Cool-Data project nr. 0177-00066B, both funded by the Danish Innovationsfonden. Fabian Scheller kindly acknowledges the financial support of the European Union’s research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 713683 (COFUNDfellowsDTU). The authors also thank three anonymous reviewers for their helpful comments on an earlier version of this paper. The usual disclaimer applies.Peer reviewedPostprin

    A neuroskeletal atlas: Spatial mapping and contextualization of axon subtypes innervating the long bones of C3H and B6 mice

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    Nerves in bone play well-established roles in pain and vasoregulation and have been associated with progression of skeletal disorders, including osteoporosis, fracture, arthritis, and tumor metastasis. However, isolation of the region-specific mechanisms underlying these relationships is limited by our lack of quantitative methods for neuroskeletal analysis and precise maps of skeletal innervation. To overcome these limitations, we developed an optimized workflow for imaging and quantitative analysis of axons in and around the bone, including validation of Baf53b-Cre in concert with R26R-tdTomato (Ai9) as a robust pan-neuronal reporter system for use in musculoskeletal tissues. In addition, we created comprehensive maps of sympathetic adrenergic and sensory peptidergic axons within and around the full length of the femur and tibia in two strains of mice (B6 and C3H). In the periosteum, these maps were related to the surrounding musculature, including entheses and myotendinous attachments to bone. Three distinct patterns of periosteal innervation (termed type I, II, III) were defined at sites that are important for bone pain, bone repair, and skeletal homeostasis. For the first time, our results establish a gradient of bone marrow axon density that increases from proximal to distal along the length of the tibia and define key regions of interest for neuroskeletal studies. Lastly, this information was related to major nerve branches and local maps of specialized mechanoreceptors. This detailed mapping and contextualization of the axonal subtypes innervating the skeleton is intended to serve as a guide during the design, implementation, and interpretation of future neuroskeletal studies and was compiled as a resource for the field as part of the NIH SPARC consortium. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

    Carbon Sequestration in Managed Temperate Coniferous Forests Under Climate Change

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    Management of temperate forests has the potential to increase carbon sinks and mitigate climate change. However, those opportunities may be confounded by negative climate change impacts. We therefore need a better understanding of climate change alterations to temperate forest carbon dynamics before developing mitigation strategies. The purpose of this project was to investigate the interactions of species composition, fire, management, and climate change in the Copper–Pine Creek valley, a temperate coniferous forest with a wide range of growing conditions. To do so, we used the LANDIS-II modelling framework including the new Forest Carbon Succession extension to simulate forest ecosystems under four different productivity scenarios, with and without climate change effects, until 2050. Significantly, the new extension allowed us to calculate the net sector productivity, a carbon accounting metric that integrates aboveground and belowground carbon dynamics, disturbances, and the eventual fate of forest products. The model output was validated against literature values. The results implied that the species optimum growing conditions relative to current and future conditions strongly influenced future carbon dynamics. Warmer growing conditions led to increased carbon sinks and storage in the colder and wetter ecoregions but not necessarily in the others. Climate change impacts varied among species and site conditions, and this indicates that both of these components need to be taken into account when considering climate change mitigation activities and adaptive management. The introduction of a new carbon indicator, net sector productivity, promises to be useful in assessing management effectiveness and mitigation activities

    Image Analysis to Determine Intramuscular Fat in Muscle

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    The area of intramuscular fat in Holstein steer longissimus was determined using an image analyzing system. Slaughter weights of 500, 636 and 773 kg differed (p \u3c 0.05) for intramuscular fat area, marbling score, and ether extractable lipid . Repeated measurements of intramuscular fat area in a given section showed high accuracy . However, comparing two sections from the same sample, there was often a large difference in fat content between the sections. Fat content determined by the imaging system was correlated significantl y with marbling score (r = 0.49) and ether extractable lipid (r = 0.34). Sampling is critical, and in order to obtain a high correlation several samples would be required from each muscle

    Electron attachment to valence-excited CO

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    The possibility of electron attachment to the valence 3Π^{3}\Pi state of CO is examined using an {\it ab initio} bound-state multireference configuration interaction approach. The resulting resonance has 4Σ−^{4}\Sigma^{-} symmetry; the higher vibrational levels of this resonance state coincide with, or are nearly coincident with, levels of the parent a3Πa^{3}\Pi state. Collisional relaxation to the lowest vibrational levels in hot plasma situations might yield the possibility of a long-lived CO−^- state.Comment: Revtex file + postscript file for one figur

    Knockout of TSC2 in Nav1.8+ neurons predisposes to the onset of normal weight obesity

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    OBJECTIVE: Obesity and nutrient oversupply increase mammalian target of rapamycin (mTOR) signaling in multiple cell types and organs, contributing to the onset of insulin resistance and complications of metabolic disease. However, it remains unclear when and where mTOR activation mediates these effects, limiting options for therapeutic intervention. The objective of this study was to isolate the role of constitutive mTOR activation in Nav1.8-expressing peripheral neurons in the onset of diet-induced obesity, bone loss, and metabolic disease. METHODS: In humans, loss of function mutations in tuberous sclerosis complex 2 (TSC2) lead to maximal constitutive activation of mTOR. To mirror this in mice, we bred Nav1.8-Cre with TSC2 RESULTS: By lineage tracing, Nav1.8-Cre targeted peripheral sensory neurons, a subpopulation of postganglionic sympathetics, and several regions of the brain. Conditional knockout of TSC2 in Nav1.8-expressing neurons (Nav1.8-TSC2 CONCLUSIONS: Knockout of TSC2 in Nav1.8+ neurons increases itch- and anxiety-like behaviors and substantially modifies fat storage and metabolic responses to HFD. Though this prevents HFD-induced weight gain, it masks depot-specific fat expansion and persistent detrimental effects on metabolic health and peripheral organs such as bone, mimicking the \u27normal weight obesity\u27 phenotype that is of growing concern. This supports a mechanism by which increased neuronal mTOR signaling can predispose to altered adipose tissue distribution, adipose tissue expansion, impaired peripheral metabolism, and detrimental changes to skeletal health with HFD - despite resistance to weight gain

    How robust are future projections of forest landscape dynamics? Insights from a systematic comparison of four forest landscape models

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    Projections of landscape dynamics are uncertain, partly due to uncertainties in model formulations. However, quantitative comparative analyses of forest landscape models are lacking. We conducted a systematic comparison of all forest landscape models currently applied in temperate European forests (LandClim, TreeMig, LANDIS-II, iLand). We examined the uncertainty of model projections under several future climate, disturbance, and dispersal scenarios, and quantified uncertainties by variance partitioning. While projections under past climate conditions were in good agreement with observations, uncertainty under future climate conditions was high, with between-model biomass differences of up to 200 t ha−1. Disturbances strongly influenced landscape dynamics and contributed substantially to uncertainty in model projections (~25–40% of observed variance). Overall, model differences were the main source of uncertainty, explaining at least 50% of observed variance. We advocate a more rigorous and systematic model evaluation and calibration, and a broader use of ensemble projections to quantify uncertainties in future landscape dynamics

    Myriapoda at "Reserva Ducke", Central Amazonia/Brazil

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    Myriapoda contains the four recent classes Chilopoda, Diplopoda, Pauropoda and Symphyla. In total, 159 families, 2166 genera and >15162 species are known world-wide. Twenty-nine families, >93 genera and >401 described species occur in Amazonia. One-fifth of the families presently known in the myriapods are represented in Amazonia. About 3% of all described species live, and at least 9% of the species estimated to exist world-wide in Myriapoda are assumed to live in Amazonia. From the forest reserve 'Reserva Ducke' near Manaus, 22 families, 38 genera and 73 described species are known at present. The Chilopoda represent 5 families, 9 genera, 23 species and one undescribed morphospecies, the Diplopoda 13 families, 18 described genera, 14 species and 19 undescribed morphospecies, the Pauropoda 2 families, 7 genera, 31 species, and the Sympyla 2 families, 4 genera and 5 species. All names are liste
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