In this second installment of my series on the physics of native gardening, I’ll talk about the physics of birds. We get a lot of birds in our yard. Robins visit the lawn and our crabapple tree. Too many house sparrows come to our bird feeders; they’re invasive pests. We see lots of blue jays, those big bullies, as well as goldfinches, downy woodpeckers, and black-capped chickadees. Every fall we know that winter is approaching when the dark-eyed juncos come down to Michigan from Canada. Canadian geese fly overhead, but they never stop at our house. Flight I often see birds high in the sky ..read more

Since my retirement, I’ve started gardening with native plants. Originally this was an interest of my wife’s, but through her I became interested too. We live in a traditional suburban neighborhood, with most of the homes having primarily turf grass lawns that are maintained with a lot of water, fertilizer, and herbicides. But whether the neighbors like it or not, we have changed. Each year, we convert more and more of our yard to native flower gardens. We have a rain garden in a low spot in the back yard, and several other gardens are back there too. In the front, under our crabapple and serv ..read more

Want a sneak peek at one of the new homework problems tentatively included in the 6th edition of Intermediate Physics for Medicine and Biology? Today I present a problem related to the flawed “cyclotron resonance hypothesis.” A lot of nonsense has been written about the idea of extremely low frequency electromagnetic fields influencing biology and medicine, and one of the proposed mechanisms for such effects is cyclotron resonance.  In Section 8.1 of the 5th edition of IPMB, Russ Hobbie and I discuss the cyclotron. One important application of magnetic forces in medicine is the cyclotron ..read more

Introduction Today’s question is: do mutations happen randomly, or are they caused by some selective pressure? In other words, are mutations a Darwinian event where they happen by chance and then natural selection selects those that are favorable to pass on to the offspring, or are mutations Lamarckian where they happen because they help a species survive (like a giraffe constantly stretching its neck to reach the leaves at the top of the tree, thereby making its neck longer, and then passing that acquired trait to its offspring). To determine which of these two hypotheses is correct, we need ..read more

What is electromagnetic hypersensitivity? It’s an alleged condition in which a person is especially sensitive to weak radiofrequency electromagnetic fields, such as those emitted by a cell phone or other wireless technology. All sorts of symptoms are claimed to be associated with electromagnetic hypersensitivity, such as headaches, fatigue, anxiety, and sleep disturbances. An example of a person who says he has electromagnetic hypersensitivity is Arthur Firstenberg, author of The Invisible Rainbow, a book about his trials and tribulations. Many people purportedly suffering from electromagnetic ..read more

J. Patrick Reilly died on October 28 in Silver Spring, Maryland, at the age of 87. He was a leader in the field of bioelectricity, and especially the study of electrical stimulation. Russ Hobbie and I didn’t mention Reilly in Intermediate Physics for Medicine and Biology, but I did in my review paper “The Development of Transcranial Magnetic Stimulation.” J. Patrick Reilly of the Johns Hopkins Applied Physics Laboratory calculated electric fields in the body produced by a changing magnetic field, although primarily in the context of neural stimulation caused by magnetic resonance imaging (MRI ..read more

Medical physicist Willi Kalender died on October 20 at the age of 75. Kalender was an inventor of spiral computed tomography. Russ Hobbie and I describe spiral CT in Chapter 16 of Intermediate Physics for Medicine and Biology. Figure 16.25 shows the evolution of the detector and source configurations [of CT]. The third generation configuration is the most popular. All of the electrical connections are made through slip rings. This allows continuous rotation of the gantry and scanning in a spiral as the patient moves through the machine. Interpolation in the direction of the axis of rotation ..read more

From Brownian Motion to Virtual Biopsy: A Historical Perspective from 40 years of Diffusion MRI, by Denis Le Bihan Denis Le Bihan recently published an open access review article in the Japanese Journal of Radiology titled “From Brownian Motion to Virtual Biopsy: A Historical Perspective from 40 years of Diffusion MRI” (https://doi.org/10.1007/s11604-024-01642-z). The article explores in depth several of the concepts that Russ Hobbie and I describe in Section 18.13 (Diffusion and Diffusion Tensor MRI) of Intermediate Physics for Medicine and Biology. The introduction begins (referenc ..read more

Where can you find trusted information about public health? Ordinarily, I would say from the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), or the Food and Drug Administration (FDA). I hope these critical institutions remain reliable authorities, but with the recent election results I think it’s wise to seek other independent sources. Today I focus on two that I find useful. A screenshot of yourlocalepidemiologist.substack.com Dr. Katelyn Jetelina is the founder of “Your Local Epidemiologist,” a public health newsletter that reaches nearly 3 ..read more

Yesterday was the International Day of Medical Physics. This event is organized by the International Organization for Medical Physics, and is held each year on November 7, the birthday of Marie Curie. This year’s theme is “Inspiring the Next Generation of Medical Physicists.” The IOMP held a poster design contest to celebrate the event. The winning poster was created by Lavanya Murugan from Rajiv Gandhi Government General Hospital and Madras Medical College in Chennai, India. IDMP coordinator Ibrahim Duhaini (who works right here in Michigan at Wayne State University) wrote that “Her artwork ..read more