To Predict Effects Of Global Warming, Scientists Looked Back 20,000 Years

As the climate warms, drought is killing large numbers of trees in California. Scientists are looking to the past to try and understand how the ecosystems of today may be changing.

More than 40 researchers concluded that climate change would make ecosystems such as deciduous forests, grasslands and Arctic tundra unrecognizable.

(Image credit: Ashley Cooper/Getty Images)

News : NPR https://ift.tt/2PS7HYf August 30, 2018 at 10:23PM

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Solving Van der Pol equation with ivp_solve

Van der Pol’s differential equation is The equation describes a system with nonlinear damping, the degree of damping given by μ. If μ = 0 the system is linear and undamped, but for positive μ the system is nonlinear and damped. We will plot the phase portrait for the solution to Van der Pol’s equation in Python using SciPy’s new ODE solver ivp_solve . The function ivp_solve does not solve second-order systems of equations directly. It solves systems of first-order equations, but a second-order differential equation can be recast as a pair of first-order equations by introducing the first derivative as a new variable. Since y is the derivative of x , the phase portrait is just the plot of ( x , y ). If μ = 0, we have a simple harmonic oscillator and the phase portrait is simply a circle. For larger values of μ the solutions enter limiting cycles, but the cycles are more complicated than just circles. Here’s the Python code that made the plot. from scipy import linspace from ...

Lawyer: 'Socialite Grifter' Anna Sorokin 'Had To Do It Her Way' (And Steal $275,000)

Opening statements were made in the "Socialite Grifter" trial on Wednesday, and both sides provided extremely different reasons why Anna Sorokin allegedly scammed a number of people and institutions out of $275,000. [ more › ] Gothamist https://ift.tt/2HXgI0E March 29, 2019 at 12:33AM

NYC's Deadliest Trash Hauling Company Is Going Out Of Business

Sanitation Salvage, the embattled private trash hauling company responsible for two deaths and countless safety violations , has surrendered its license and is going out of business. The company announced the decision in a letter sent to the Business Integrity Commission this week, city officials said. [ more › ] Gothamist https://ift.tt/2TYFVLx November 28, 2018 at 07:14PM

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