You may know that I write science articles for the a science and technology website called Bright Hub. I just completed a short series on the basics of stem cells: terminology, classification, and sources. Each article is meant to stand alone, so they are a little repetitive.

These are not opinion pieces, so I did not express my personal strenuous opposition to any use of embryonic stem cells. I did carefully note in every article in which embryonic stem cells are mentioned that harvesting embryonic stem cells kills the embryo.

Only one article is about stem cell treatments. That's because I was only assigned to write one. Here are the links:

• Facts about stem cells
• Types of stem cells
• How stem cells are harvested
• Cloning and stem cells
• Heart disease treatment with stem cells

Would you like to see me write more about stem cells? Are there any particular topics you would like to see covered? I can always write as much as I like in this space, and I can ask my editor for more stem cell assignments at Bright Hub.

I am jumping on a meme bandwagon: Seven Quick Takes Friday, hosted by Jen F. at Conversion Diary. Since this is a blog about science and faith, not a personal diary, I hope Jen will forgive me if my seven snippets consist of news, info, and thoughts about those subjects.

1.

If you grow your young in a uterus, but you have not evolved a placenta, how do you feed them? For the gray nurse shark, aka the sand tiger shark, the answer is incestuous cannibalism. Gray nurse shark pups in the womb eat each other for nourishment, so only two are born per pregnancy (females have two uteruses). Since they are endangered, marine biologist Nick Otway is trying to develop an artificial uterus for gray nurse shark pups. Back when I worked as an aquarium biologist, we had several of these huge sharks. They are quite docile despite their fearsome complement of teeth.

At right: Grey nurse shark at the Minnesota Zoo, courtesy Joe Lencioni. (CC) Some rights reserved.

2.

Check out this video of comedian Stephen Crowder, hosted by the Raving Theist (formerly the Raving Atheist). He does an over-the-top parody comparing Planned Parenthood to a used car salesman.

3.

From the world of physics (via Scientific American) comes a story about the continued dissonance between Einstein's special relativity and quantum mechanics. This particular story has to do with a principle of special relativity called locality, which conflicts with a principle of quantum mechanics called entanglement. Of note is a comment buried on page 4 of the online article:

The old aspirations of physics to be a guide to metaphysics, to tell us literally and straightforwardly how the world actually is—aspirations that had lain dormant and neglected for more than 50 years—began, slowly, to reawaken.

This is good news for philosophers who, like me*, view reality as a concrete thing and truth as absolute.

*Not that I am any kind of philosopher.

4.

Shame on the New York Times for its headline, "For Catholics, a Door to Absolution is Reopened." The article is about the church's promotion of indulgences — which are decidedly not the same as absolution, and which have never had the door closed, having always been available. The Times notes that the tradition of indulgences is "one of the most complicated to explain," then proceeds to do a rotten job of explaining it. In particular is the omission of the crucial point that Purgatory is a process of purification, of making us more like God so we can enter his heaven, not a place in space-time where one serves a sentence of days or years. (Hat tip to Science and Religion News.)

5.

When Pluto was removed from the list of planets, it became the first discovered member in a brand-new class of space objects: the dwarf planets. In a way, this is actually a promotion, not a demotion. But apparently a lot of people are emotionally attached to Pluto as a planet. In 2007, the State of New Mexico (home of Pluto's discoverer, Clyde Tombaugh) declared Pluto officially a planet. (Hat tip to Spaceports blog.) This reminds me of the apocryphal tale of one of the Appalachian states (Tennessee?) trying to declare the mathematical constant pi as equal to exactly 3.

At right: Image of Pluto and its moons by the Hubble Space Telescope (courtesy of NASA).

6.

If you are Catholic, and the Pope himself told you to your face that you were wrong on some issue, would you reconsider your position? Apparently, Nancy Pelosi would not. She shows no signs of easing from her pro-choice stance despite a face-to-face reprimand from Pope Benedict XVI. One prays that at least a seed was planted.

7.

Until now, the Alavesia fly was an insect known only from amber fossils from the Cretaceous period, before the mass extinction that killed the dinosaurs and many other species. Now two species of living Alavesia have been found in Namibia and have been dubbed "living fossils" by the media. A completely new suborder of insects, the Mantophasmatodea, was discovered as well. There is still much we do not know about the mysterious world of living things. It's no surprise the new discoveries were insects; there are an estimated six to ten million species of insects, but only about a million have been described.

Once, babies were considered gifts from God. Then we invented in vitro fertilization and took God out of the equation.

Now that babies are commodities, it stands to reason that we should be able to custom-order them. And finally, we can, thanks to Fertility Institutes of Los Angeles, California.

This clinic allows prospective parents to choose cosmetic traits in their offspring, such as hair color and eye color. Before today, baby trends included stroller brands and popular first names. Now baby trends can include baby blues!

Can we go any further on the path to making human life a commodity rather than a sacred gift? I'm asking seriously, not rhetorically. Leave an answer in the comments.

This post is a contribution to the blog swarm "Blog for Darwin," held from February 12-15, 2009, to celebrate the 200th anniversary of Charles Darwin's birth.

When Charles Darwin published On the Origin of Species in 1859, introducing the world to the revolutionary concept of evolution through natural selection, he noted that "perhaps ... the most obvious and gravest objection which can be urged against my theory" was the apparent lack of "transitional" fossils in the geological record. He speculated that the reason that "geology ... does not reveal [a] finely graded organic chain" of intermediate forms was because of the paucity of fossil discoveries at the time.

In one sense, every species that has ever existed is a "transitional" form; it reflects characteristics of its ancestors, and its characteristics will be reflected in its descendants. But humans are impressed by the dramatic, and in the years since Darwin's first book on evolution was published, some very dramatic fossils, intermediate between two large classes, have been discovered.

The most famous of these is Archaeopterix, which depending on one's interpretation is either a a bird with teeth and clawed hands or a feathered, flying dinosaur. But another lesser-known fossil is equally dramatic as an example of a transitional form: the marvelous Ichthyostega.

Ichthyostega is an intermediate form between fishes and amphibians from the late Devonian period, about 365 million years ago. One could describe it as a fish with legs that could walk around on land, or one could say it was an amphibian with the head and tail of a fish. Since fish have their weight supported by the water, Ichthyostega faced the problem of supporting its weight on land, which was accomplished by thickened, overlapping ribs — a clumsy, primitive solution necessary because it had so recently evolved from its lungfish-like ancestors.

Ichthyostega had seven toes on each hind foot, notable since the number of toes on tetrapod* feet stabilized at five early in their evolution. Its shoulder and hip had adaptations to help it move about on land. Its hind limbs could support its body as a juvenile, but were likely too weak to support its full weight on land in adulthood. It is hypothesized that juveniles could leave the water to escape predators, but adults only partially pulled themselves out of the water to sun themselves.

Ichthyostega is one of many fossils that fill in the natural history of the evolution of tetrapods from fish. The story is still not complete: "Romer's gap" (named after paleontologist Alfred Sherwood Romer) is a 20 million year period of missing fossils between Ichthyostega and its contemporaries and the next-oldest known tetrapods.

Gaps in the fossil record like this were a worry to Darwin, who recognized them as a potential rebuttal of his seminal theory. Yet absence of evidence is not evidence of absence; the most parsimonious explanation for Romer's gap remains the one Darwin put forth — the incompleteness of the geological record. Charles Darwin's extraordinary theory is now secure as one of the most well-established, concrete principles of biology.

*Tetrapods are four-legged vertebrates and their descendants; in other words, all vertebrates except fish.

More information on Ichthyostega

• Ichthyostega from the Tree of Life web project
• Cladogram showing Ichthyostega's place in the evolution of tetrapods (Palaeos database)

Ichthyostega image information

• Top right: Reconstruction of a juvenile Ichthyostega from the National Museum of Natural Science in Taiwan. Photo by Alton Thompson. (CC) Some rights reserved.
• Left: Pencil drawing of Ichthyostega. From Wikimedia Commons, licensed under the GNU Free Documentation License (GFDL).
• Bottom right: Drawing of Ichthyostega skeleton. The forelimbs are incompletely fossilized and the hand morphology is unknown. From the Tree of Life web project (link above), after Ahlberg et al. 2005. (CC) Some rights reserved.
  

The youngest Leave the lights on blogger, my 14-month-old son, got three shots last week. He and his brother have had every vaccination recommended by pediatricians. I understand that a lot of parents are hesitant about vaccinations because of fears of their safety. Those parents should fear for the safety of their children if they don't vaccinate.

Vaccines are safe

Most of the fears about vaccinations center on the purported link between the mercury-based preservative thimerosal and autism. But study after study — most recently, one conducted in Italy — have shown that thimerosal does not cause autism. In fact, the original study that suggested the thimerosal-autism link was faked. And even if this evidence is not convincing, thimerosal is no longer used in most vaccinations.

Not vaccinating can be deadly

Last month in Minnesota, a seven-month-old baby died of Hib, or Haemophilus influenzae type b. Hib infections are vanishingly rare in the U.S. because of the routine use of the Hib vaccine, which is given at 2, 4, 6, and 12 months (this is one of the shots my son received last month). The child who died, and two of four other kids who were sickened by the Hib outbreak, were unvaccinated "because of their parents' decisions." In other words, the parents decided not to protect their children against deadly infections.

Of the other two children, one was only five months old and so had not completed the primary 3-shot series. The other had an immune deficiency. When vaccination rates are above a certain "threshold," people like these two children are protected by "herd immunity" (a term that originated in animal husbandry). The disease cannot spread because there are not enough vulnerable individuals in the population. When people choose not to be vaccinated, or not to have their children vaccinated, herd immunity suffers, and people like these two babies can be sickened.

The refusal to vaccinate one's children is a source of frustration for health officials. I cannot understand a parent's reluctance to protect their children against deadly diseases that should only be a memory in the twenty-first century.

Once you are baptized or confirmed as a Catholic, there's no way out. You are permanently marked as a Catholic, and you can only leave the Church by dying and going to hell. Even the souls in heaven and purgatory are part of the Church.

Excommunication is a "severe ecclesiastical penalty, which impedes the reception of the sacraments and the exercise of certain ecclesiastical acts" (CCC 1463). It is not expulsion from the Church, since indeed the Church cannot bind non-members, nor is it a declaration of spiritual condemnation.

Bishop Williamson and the other bishops of the Society of Saint Pius X (SSPX) were excommunicated for an audacious act of disobedience to the Pope's rightful authority in 1988. Earlier this year, that act was forgiven and the excommunication lifted. The bishops remain suspended, however, from the exercise of the functions of bishops and priests. Bishop Williamson is not allowed to act as a bishop.

One function of bishops is teaching. Bishops are to have a thorough and nuanced understanding of the Church and her teaching so they can instruct their flocks. So my jaw dropped when I read this quote attributed to the Archbishop of Freiburg, Germany, Robert Zollitsch:

"Mr. Williamson is impossible and irresponsible. I don't see a place for him anymore in the Catholic Church."

I can only assume that Archbishop Zollitsch is being quoted out of context by the German news magazine Der Spiegel. Perhaps he means there is no place for Williamson in the Church's heirarchy, that he should not have priestly or episcopal functions restored. But it is a fundamental tenet of the Catholic faith that there is a place for everyone in the Church. That's what the word "catholic" means: universal, applying to all people.

It's often said that the Church is not a museum for saints, but a hospital for sinners. World opinion is that Williamson is a grave sinner (although I leave that judgment to God).

That would mean he is a perfect candidate for membership in the Catholic Church.

I have started a new blog, my first experiment with Wordpress: Photo Mine. It's a collection of the most interesting, beautiful, and odd — in a word, remarkable — images I find on the web. And they are all free images, so you can reuse them on your own projects. Check it out!

It's almost the weekend, so let's talk about TV.

I watch FOX's House regularly. I am losing interest in the program because (besides becoming clichéd and boring) it is not realistic.

The medical cases themselves are full of inaccuracies; one is tempted to uncharitably call them lies. One character is "dying" of Huntington's chorea, which in reality is not a fatal disease at all. A patient died of acute eclampsia a month after giving birth — never mind that eclampsia is cured by delivery of the baby. In one especially infamous episode, a psychiatric condition called "mirror syndrome" was completely invented out of thin air by the writers. (There is a real condition called mirror syndrome which affects pregnant women; this illness was also featured in an episode. Oops.)

Each episode begins with an apparently healthy patient dramatically (and often graphically) collapsing. They are then whisked to Dr. House's hospital, where his team of crack doctors (a bunch who apparently failed medical ethics in school) personally conduct the procedures and tests that are normally done by nurses, radiologists, and other specialists. Dr. House invariably treats the patient more callously than can be imagined, often being deliberately cruel — and clearly delighting in it. At the end, Dr. House (or, less freqeuntly, another doctor, such as the skankily-dressed hospital administrator Dr. Cuddy) has a brilliant flash of insight that tells him the patient's true diagnosis, and treatment after that is quick and easy (unless it is incurable and the patient dies, which happens fairly often).

Scientific American blogger Jordan Lite notes that the cases are often taken from the New England Journal of Medicine's clinical problem-solving column, and that one writer-producer, David Foster, is an M.D. A book has even been written about the show, The Medical Science of House, M.D. But I find the science unrealistic. This is not how medicine is works.

A real mystery disease is usually chronic. A patient with a real "zebra" condition has usually seen many doctors. Once a diagnosis is made, if it is made, treatment is not necessarily quick and easy.

Also, a good doctor is not cruel.

CNN recently featured a story on Dr. William Gahl, who is a real-life diagnostician of rare diseases. Read this story for a realistic picture of how doctors approach medical mysteries. And keep watching House, if you enjoy it. But remember that it's just as fictional with its science as Star Trek and Battlestar Galactica.

CNN recently published an article with the deeply euphemistic title, "Woman in coma to be allowed to die." While technically true, it sounds as if it refers to a person who has begged to be allowed to stop extreme treatment measures in order to be allowed to pass in peace.

This is not true.

In fact, Eluana Englaro, an Italian woman who has been in a vegetative state, not a coma, since 1992, is not under any extreme treatment measures. (See this link for more information about the difference between coma and vegatative state.) She breathes without a ventilator. The nuns treating her are eager to continue to provide care for her for the rest of her natural life.

But Ms. Englaro's own family wants to stop feeding her so she will die of dehydration. This is not a dignified death.

In a letter published in a local newspaper, her caregivers wrote, "We don’t ask anything but the silence and the liberty to love and to devote ourselves to those who are weak, poor and little in return." (Source: Life Site News.)

What a tragic turn of events. Ms. Englaro is not suffering (not that suffering would justify murdering her through deliberate neglect) and not a burden on anybody (not that being a burden would justify it, either). If she is capable of suffering (and I pray she is not), she certainly will suffer in the two to three weeks it takes her to die of dehydration, a miserable, painful, and barbaric way to die.

Above: Space shuttle Columbia lifting off at the beginning of STS-107, its 28th and final mission. Courtesy of NASA.

To NASA, it's STS-107. To most of the rest of the world, it was the Space Shuttle Columbia disaster of 2003. A briefcase-sized chunk of foam weighing a little over a pound hit the orbiter's wing at 800 feet per second — that's about 550 miles per hour — damaging the thermal protection system (TPS). The compromised TPS was not adequate to the 3000° F reentry temperatures, and on its landing approach, the shuttle broke up into a handful of fireballs over Texas and Louisiana.

The shuttle disaster happened on my birthday. It's the worst birthday I have ever had.

This catastrophic event recalled to mind the Challenger disaster of 1986, seventeen years and four days earlier. I was in elementary school, and they wheeled a TV into our classroom so we could watch the shuttle explode over the Atlantic Ocean.

Stephanie Barr is a NASA engineer who writes the blog Rocket Scientist. She was part of the STS-107 team, and has a blog post remembering the Columbia tragedy. Go over and read it right now. I'll wait.

Then come back and tell me where you were when the Challenger and Columbia disasters happened.