fertility
dr. dolittle | October 27, 2016 Image of a deer mouse from Seney Natural History Association, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=29576617
Deer mice are known for being quite promiscuous. In fact, it is not uncommon to find a litter of deer mice with multiple fathers. Dr. Hopi Hoekstra and colleagues at Harvard University's Department of Organismic and Evolutionary Biology discovered that the tail of deer mice sperm have longer midsections than found in monogamous mice. What this means is that their sperm can swim better and faster, thereby reaching an egg sooner than sperm from other…
kkrisberg | September 16, 2016In a new study — the first of its kind — researchers fed water laced with fracking chemicals to pregnant mice and then examined their female offspring for signs of impaired fertility. They found negative effects at both high and low chemical concentrations, which raises red flags for human health as well.
“These are preliminary findings,” Susan Nagel, the study’s senior author and an associate professor in Obstetrics, Gynecology and Women’s Health at the University of Missouri School of Medicine, told me. “But I think they suggest that we should absolutely be looking more closely at the…
kkrisberg | April 15, 2016Lead isn’t the only toxin threatening the safety of community drinking water. A recent study on water located downstream from a West Virginia fracking disposal site uncovered levels of endocrine-disrupting chemicals high enough to adversely impact the aquatic animals living there. And that means human health could be at risk too.
“We can’t make any direct (human health) assumptions about this particular water,” said study co-author Susan Nagel, an associate professor in the University of Missouri School of Medicine’s Division of Obstetrics, Gynecology and Women’s Health. “But we certainly…
oracknows | July 3, 2013Here we go again.
Oh, well. These things come in waves, and sometimes I have theme weeks. Right now, this week appears to be developing into a week of quackademic medicine involving dubious acupuncture studies. Yesterday, it was acupuncture for lymphedema after breast cancer surgery, a study coming right about what is rapidly becoming the Barad-dûr of cancer quackademia, Memorial Sloan-Kettering Cancer Center. How a hospital that is so awesome in every other way can have such a blind spot bigger than the Eye of Sauron, I don't know, but it does, and the result is a steady stream of…
sastyk | March 7, 2013From Agrilife, apparently we're going to spend 3 million bucks to confirm the obvious - if you only breed for one thing, maximum milk production, you will be casting a lot of other critical traits to the winds:
“Fertility is a critical component of efficient dairy production,” Pinedo said. “Failure to attain and maintain a timely pregnancy is a major reason for production loss in dairy herds. Consequences of low fertility include a reduced percentage of cows at the early stages of lactation, increments in insemination costs, premature culling and delayed genetic progress.
“The decline in…
gregladen | January 13, 2013I knew a couple who had spent a lot of time in the Congo in the 1950s. He was doing primatology, and she was the wife of the primatologist. And when she spoke of the Congo or Uganda, where they spent most of the time, she always said "The thing about Africa is that there's no place to sit down."
Now, I've been all over Africa, and I've sat down in Nigeria, Kenya, Lesotho, Botswana. I admit having had a hard time finding a place to sit down in Namibia but that's because I've only been in places with no chairs but there were a lot of rocks. I once sat for a long time on a curb in Rwanda.…
jhalper | January 25, 2011Two recent papers to come out of the Weizmann Institute have possible medical applications -- one in preventing pregnancy, the other in preventing the deadly effects of nerve gas.
The first might give pause to those among us who are "believers" in antioxidants. It seems that those "nasty" molecules they eliminate -- reactive oxygen species -- have a positive role to play, at least when it comes to fertility. In the study, mopping up reactive oxygen species with antioxidants in mouse ovaries blocked ovulation. So while women who are trying to get pregnant might consider knocking off the acai…
sastyk | January 24, 2011Gardeners like to compete with each other over who has the worst soil. You wouldn't think we'd be proud of this, but what can I say, we're a strange bunch. One will argue for his hard clay, baked in the sun, another for her sand, without a trace of organic matter. I've got my own candidate for the worst soil ever - the stuff in the beds around my house.
Oh, texturally, it is among the best I've got - sandy loam, warms up nicely, isn't too wet like much of the rest of my soil. It had some nice enough foundation plantings, and I mostly ignored it for the first few years I was here. But a…
sastyk | April 5, 2010Note: This is a repeat from ye olde blogge, brought about by the barn cleaning we're engaged in.
From December to March or the beginning of April, we simply don't clean out the barn. This sounds as if it might be gross, but it really isn't - we keep layering on bedding, and sufficient carbon keeps it from smelling bad - earthy and barnish, sure, but not particularly icky. We don't just do this because we're lazy - this is good husbandry for our climate. The barn has cement floors, left over from its days as a garage, and those cement floors get cold in the winter. A very thick layer of…
pronald | March 5, 2010Science Magazine this week published the winners of this year's International Science and Engineering Visualization Challenge.
Self-Fertilization: Heiti Paves and Birger Ilau, Tallinn University of Technology
Within its tiny white flowers, thale cress (Arabidopsis thaliana) does what most plants avoid: It fertilizes itself. Heiti Paves of Tallinn University of Technology in Estonia took this photograph of the flower with its pollen grains and ovaries stained blue to show the process in action. From the six pollen heads, the grains grow thin tubes toward the bean-shaped ovaries in the flower…
pronald | February 13, 2010When I give lectures about the global food supply and the environment, often someone in the audience will comment that the best way to solve the problem is to quit producing so much food.
I find this type of "Let 'em starve" approach quite horrific from a humanitarian view. It also makes no sense scientifically.
First of all, it is well established that increases in economic and social development (think: enough food to eat) coincide with substantial declines in human fertility and population growth rates.
According to this recent article in Nature, "As a result of this close connection…
gregladen | August 31, 2009Good morning and welcome to another installment of "The Falsehoods." Today's falsehood is the assertion that the poor have more babies than the rich, or that the poor just have more babies to begin with. In comparison to ... whatever.
Now, before you rush off to the Internet and find some table or graph that shows higher fertility in women of lower SES than higher SES, or a high birth rate among Nigerians, I want to acknowledge right away that such evidence is easy to find, and it is easy to take that evidence and construct the obnoxious sentence that titles this post. Yes, that is all…
edyong | August 5, 2009You wouldn't think it to look at our skyrocketing global population, but many parts of the world are experiencing serious falls in fertility. A country's fertility rate is the average number of children born to a woman over her lifetime. In most developed countries, it needs to be 2.1 or higher if the number of newborns is to compensate for citizens who die. In developing countries, where death is a more frequent visitor, this replacement threshold is even higher.
The problem is that declining fertility is intimately linked with a country's economic and social development. As a result, more…
emjohnson | July 20, 2009Mark Hemingway, the Conservative "tough-guy" for the National Review, has just posted a rant against health concerns for the endocrine disruptor Bisphenol A.
I've seen some estimates that over a billion people have had exposure to BPA and there isn't proof of anything. So why the big scare? I assume trial lawyers are involved in the fear mongering. That's a given. But then I saw that last year two reporters from the Milwaukee-Journal Sentinel won a George Polk Award-- a major journalism honor -- for reporting on the "dangers" of BPA. It's another reminder that there are some perverse…
edyong | April 1, 2008You could argue that life is all about cheating death and having enough sex to pass on your genes to the next generation, as many times as possible. From this dispassionate viewpoint, human reproduction is very perplexing for our reproductive potential has an early expiry date. At an average age of 38, women start becoming rapidly less fertile only to permanently lose the ability to have children some 10 years later during menopause.
From an evolutionary point of view, this decline is bizarre. Other long-lived animals stay fertile until close to the end of their lives, with elephants…