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Two methods for the laboratory-scale formation of aerosols of nanosized particles of precipitated calcium carbonate (PCC), for potential use in Stratospheric Aerosol Injection (SAI), a Solar Radiation Management (SRM) technique, are described. The first uses the coarse fluidization of bulk PCC in a simple vessel, followed by dispersal using a commercially available two-fluid nozzle. The manufacturer’s measured particle mass distribution for the bulk material, and sprayed aerosol particle mass distributions are compared, indicating that the sprayed particles are well separated in spite of a notoriously problematic agglomeration tendency. The method is suitable for scale-up. A second dispersal method, useful for small laboratory experiments, using liquid carbon dioxide as a dispersant as well as spray propellant gave similar results. The mass mode diameters measured here (0.89 to 1.4 μm) differ from that stated by the manufacturer (0.7 μm), but the distributions are consistent in showing complete separation of the particles.

The idea behind the marine cloud-brightening (MCB) geoengineering technique is that seeding marine stratocumulus clouds with copious quantities of roughly monodisperse sub-micrometre sea water particles might significantly enhance the cloud droplet number concentration, and thereby the cloud albedo and possibly longevity. This would produce a cooling, which general circulation model (GCM) computations suggest could-subject to satisfactory resolution of technical and scientific problems identified herein-have the capacity to balance global warming up to the carbon dioxide-doubling point. We describe herein an account of our recent research on a number of critical issues associated with MCB. This involves (i) GCM studies, which are our primary tools for evaluating globally the effectiveness of MCB, and assessing its climate impacts on rainfall amounts and distribution, and also polar sea-ice cover and thickness; (ii) high-resolution modelling of the effects of seeding on marine stratocumulus, which are required to understand the complex array of interacting processes involved in cloud brightening; (iii) microphysical modelling sensitivity studies, examining the influence of seeding amount, seed-particle salt-mass, air-mass characteristics, updraught speed and other parameters on cloud-albedo change; (iv) sea water spray-production techniques; (v) computational fluid dynamics studies of possible large-scale periodicities in Flettner rotors; and (vi) the planning of a three-stage limited-area field research experiment, with the primary objectives of technology testing and determining to what extent, if any, cloud albedo might be enhanced by seeding marine stratocumulus clouds on a spatial scale of around 100×100 km. We stress that there would be no justification for deployment of MCB unless it was clearly established that no significant adverse consequences would result. There would also need to be an international agreement firmly in favour of such action.

The large-scale production of vast numbers of suitable salt nuclei and their upward launch is one of the main technological barriers to the experimental testing of marine cloud brightening (MCB). Very promising, though not definitive, results have been obtained using an adapted version of effervescent spray atomization. The process is simple, robust and inexpensive. This form of effervescent spraying uses only pressurized water and air sprayed from small nozzles to obtain very fine distributions. While it is far from optimized, and may not be the best method if full deployment is ever desired, we believe that even in its present form the process would lend itself well to preliminary field test investigations of MCB. Measurements obtained using standard aerosol instrumentation show approximately lognormal distributions of salt nuclei with median diameters of approximately 65nm and geometric standard deviations slightly less than2. However, these measurements are not in agreement with those based on scanning electron microscopy imaging of collected particles, an observation that has not yet been explained. Assuming the above distribution, 1015 particles per second could be made with 21kW of spray power, using approximately 200 nozzles. It is envisioned that existing snow making equipment can be adapted to launch the nuclei 60100m into the air, requiring approximately 20kW of additional power.

The large-scale production of vast numbers of suitable salt nuclei and their upward launch is one of the main technological barriers to the experimental testing of marine cloud brightening (MCB). Very promising, though not definitive, results have been obtained using an adapted version of effervescent spray atomization. The process is simple, robust and inexpensive. This form of effervescent spraying uses only pressurized water and air sprayed from small nozzles to obtain very fine distributions. While it is far from optimized, and may not be the best method if full deployment is ever desired, we believe that even in its present form the process would lend itself well to preliminary field test investigations of MCB. Measurements obtained using standard aerosol instrumentation show approximately lognormal distributions of salt nuclei with median diameters of approximately 65 nm and geometric standard deviations slightly less than 2. However, these measurements are not in agreement with those based on scanning electron microscopy imaging of collected particles, an observation that has not yet been explained. Assuming the above distribution, 1015 particles per second could be made with 21 kW of spray power, using approximately 200 nozzles. It is envisioned that existing snow making equipment can be adapted to launch the nuclei 60–100 m into the air, requiring approximately 20 kW of additional power.

Cancer metastasis relies on an orchestration of multiple traits driven by different functional interacting modules including metabolism and epithelial-mesenchymal transition (EMT). Cancer cells can adjust their metabolism during metastasis by increasing oxidative phosphorylation without compromising glycolysis, acquiring a hybrid metabolic phenotype (W/O). Often required by metastasis, cancer cells engage EMT and can acquire a hybrid epithelial/mesenchymal (E/M) phenotype. Both the W/O and E/M states are associated with high metastatic potentials. Many regulatory links coupling metabolism and EMT have been identified, but how these two modules regulate each other remains largely unexplored. Here, we investigate the coupled decision-making networks of metabolism and EMT, and systematically analyzed the effect of their crosstalk. This crosstalk can exhibits synergistic or antagonistic effects on the acquisition and stability of different coupled metabolism-EMT states. Strikingly, the aggressive E/M-W/O state can be enabled and stabilized by the crosstalk irrespective of these hybrid states availability in individual metabolism or EMT modules. To acquire an E/M-W/O state, the W/O state emerges first, followed by the E/M state, suggesting metabolism can drive EMT. Our work emphasizes the mutual activation between metabolism and EMT, providing an important step towards understanding the multi-faceted nature of cancer metastasis. Competing Interest Statement The authors have declared no competing interest.

INTERRUPTED is a composition for a small orchestra that explores the process of creating a larger work from smaller, individual “moments.” The duration and structure of the individual movements are a response to a neurological dysfunction which limited the composer's working memory and concentration. The composer's former methodology of through-composing and evolving large structural elements over extended time spans was no longer possible. A new creative process was developed where the current moment at hand was the only moment that mattered. This new approach was both practical and philosophical, and allows the freedom of writing an idea that may have little to do with what precedes it, and may or may not influence what follows. The common thread linking the movements was a loose system of pitch structure that was developed from the intersection of overlapping enneatonic and octatonic scales. The resulting mini-compositions serve as individual “moments” which were then arranged and edited with some repeating variations, to create a cohesive whole. INTERRUPTED showed the composer that the perceived limitation of one's creative process can be re-tuned to become a strength and an outlet for new directions in creative output.

We consider a wave equation [special characters omitted]on Ω × [0, T], where Ω is a bounded region of a Riemannian manifold. The coefficients a ij(x) give rise to a new Riemannian metric g on Ω; we do all our work in terms of g. We seek to control the solution u(x, t) by imposing Dirichlet conditions on part of the lateral boundary of our region, Γ1 × [0, T], where Γ 1 ⊂ Γ = ∂Ω. Given general initial conditions, what circumstances guarantee that we can steer u(x, t ) to zero by time T? Using Carleman estimates analogous to work of Lasiecka, Triggiani and Yao (LTY), but in a more fully Riemannian setting, we show control in time [special characters omitted] if there is a g-convex function v with 0 ≤ v ≤ K on [special characters omitted], Hessian satisfying D2v ≥ 2ρg, and [special characters omitted] ≤ 0 on the uncontrolled boundary Γ0 = ∂Ω\\Γ 1. We also show that the same result follows by elementary calculus from a geometric optics result of Bardos, Lebeau and Rauch (BLR), in the infinitely differentiable case. Geometric optics are more general than convex functions in showing control. We provide an example called the “Wiffle-ball”, a manifold-with-boundary where geometric optics implies control in a short time, but a strictly convex function cannot exist. We look into constructing convex functions that satisfy the LTY hypotheses for various regions Ω and controllable boundaries Γ1, and we look at cases where such construction is bound to fail. We show that convex functions on Γ1 can be extended into a neighborhood of Γ1 in Ω. These ideas are made clearer by considering the level sets of a convex function. We examine the case where the coefficients aij( x) have a jump across a smooth (n − 1)-dimensional interface Σ. We propose a transmission condition valid for n-dimensional regions Ω and show that it is consistent with the traditional Snell's Law. We discuss what convexity means in this case and show that a convex function can be extended into a neighborhood of the interface. Finally we discuss whether such a convex function implies control when there is an interface.

Alien invasive plant species have altered the historical descriptions of eastern U.S. forests. This dissertation used an invasive tree ( Acer platanoides) and shrub species (Berberis thunbergii ) to examine how experimental understory communities affected dynamics in a suburban deciduous forest in Central New Jersey, USA. With invasive plant removal often an unrealistic option, these community treatments (0%, 25%, 50% invasive) served as proxies for possible management outcomes to test invasive effects on native species. After only 3 growing seasons, both an A. platanoides canopy and A. platanoides saplings had strong negative impacts on native sapling and seedling growth. There was such a strong negative effect of the invasive canopy on native sapling growth that the presence of invasive saplings was less important. However, beneath a native canopy, native saplings grew significantly more in the absence of invasive saplings. Even if invasive removal in the understory were only done every 2-3 yrs, this would give native saplings release from invasive competition and time to increase in growth (Chapter 1). In two separate experiments, an invasive canopy negatively affected native seedling growth in the forest (Chapter 3), and soil collected from beneath an invasive canopy reduced native growth (greenhouse, Chapter 2). While the understory and canopy types impacted native saplings and seedlings, A. platanoides was largely unaffected (Chapters 1, 3). However, it does appear that it has the ability to shift resource allocation depending on soil type, which may give it a growth advantage over native species (Chapter 2). I did not find support of the ERH, as leaves from seedlings of A. platanoides and A. rubrum had equivalent amounts of herbivory (Chapter 3). In a litter decomposition experiment (Chapter 4), two invasive species had lower C:N ratios than the native species. Higher nitrogen content in invasive litter could alter soil nutrients and cycling and, perhaps, leave a legacy of invasive impact. Experimental studies done in the field can help us increase our understanding of invasive and native species interactions, while providing us with information to guide restoration and management decisions to retain native diversity.

Thank you for the series of articles about the Open Space District. As someone who voted for this tax, I am pleased and at the same time thoroughly disgusted with how my monies have been spent.