After 26 years, the US has lost its measles elimination status
The US has lost its measles elimination status after 26 years. The available information does not explain why. (cnn.com)
Active Calculus - Multivariable, Second Edition, by Nicholas Long and Mitchel T. Keller, is an open-licensed textbook for learning calculus in several variables. Its contents move from the three-dimensional geometry and vector algebra needed for the subject to differentiation, integration, and vector calculus. The front matter includes the authors’ goals for the book, guidance on using it, and information about graphics and technology, while the chapters are divided into short sections with exercises.
The text begins with vectors, lines and planes, three-dimensional surfaces, and polar, cylindrical, and spherical coordinates. It then develops vector-valued functions and the calculus of curves, including arc length, curvature, and acceleration. The chapter on multivariable derivatives covers limits, partial derivatives, tangent planes, the chain rule, gradients, directional derivatives, and unconstrained and constrained optimization. Multiple integrals follow, with applications to area, mass, probability, and center of mass, as well as changes of coordinates. The final chapter treats vector fields and line and surface integrals, building toward Green’s, Stokes’, and the Divergence theorems. A supplementary section on conic sections rounds out the material.
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The US has lost its measles elimination status after 26 years. The available information does not explain why. (cnn.com)
SpaceX plans to shift from Falcon 9 to Starship, but Falcon 9 currently launches the only U.S. spacecraft carrying NASA astronauts to the International Space Station. With NASA contracted for only three more Dragon flights, the agency may need new crew-transport options before the station retires in 2030. (text.npr.org)
Metal-eating bacteria and corrosion are weakening the Titanic’s wreck, with parts of the ship already collapsing on the deep-sea floor. Its remains will gradually disintegrate, though the process is expected to take decades or longer. (bbc.com)
Women lost more weight than men while taking GLP-1 drugs, according to a meta-analysis of six trials involving nearly 20,000 participants. Results were similar across age, race, BMI, and blood-sugar groups, while hormones and body composition may help explain the sex difference. (medpagetoday.com)
A 12-year study of more than 440 female Asian elephants in Sri Lanka found that population losses have made their social networks smaller and more isolated. Researchers warn that crossing a social tipping point could threaten the animals’ future. (today.ucsd.edu)
Quantum computing uses quantum bits, or qubits, to process information in ways that differ from classical computers. Its software relies on quantum algorithms and is designed for specialized problems rather than replacing everyday computing. (makingsoftware.com)
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