Critical loads (CLs) are frequently used to quantify terrestrial ecosystem impacts from nitrogen (N) deposition using ecological responses such as the growth and mortality of tree species. Typically, CLs are reported as a single value, with uncertainty, for an indicator across a species' entire range. Mediating factors such as climate and soil conditions can influence species' sensitivity to N, but the magnitudes of these effects are rarely calculated explicitly.
View Article and Find Full Text PDFFluorescent lifetimes of dissolved organic matter (DOM) and associated physicochemical parameters were measured over 14 months in an estuary in Southern California, USA. Measurements were made on 77 samples from sites near the inlet, mid-estuary, and outlet to maximize the range of physicochemical variables. Time-resolved fluorescence data were well fit to a triexponential model with an intermediate lifetime component (τ: 1 to 5 ns), a long lifetime component (τ: 2 to 15 ns), and a short lifetime component (τ: < 1 ns).
View Article and Find Full Text PDFThere has been an increase in the availability and utilization of commercially available 3D printers in radiotherapy, with applications in phantoms, brachytherapy applicators, bolus, compensators, and immobilization devices. Additive manufacturing in the form of 3D printing has the advantage of rapid production of personalized patient specific prints or customized phantoms within a short timeframe. One of the barriers to uptake has been the lack of guidance.
View Article and Find Full Text PDFMethods to prepare and characterize neutron helical waves carrying orbital angular momentum (OAM) were recently demonstrated at small-angle neutron scattering (SANS) facilities. These methods enable access to the neutron orbital degree of freedom which provides new avenues of exploration in fundamental science experiments as well as in material characterization applications. However, it remains a challenge to recover phase profiles from SANS measurements.
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