Later On

A blog written for those whose interests more or less match mine.

Archive for September 16th, 2008

Tardigrades: tough little guys

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Via Very Short List, I learn that the tardigrade (“slow walker), commonly known as the water bear, is one tough little guy. From Wikipedia:

Tardigrades are very hardy animals; scientists have reported their existence in hot springs, on top of the Himalayas, under layers of solid ice and in ocean sediments. Many species can be found in a milder environment like lakes, ponds and meadows, while others can be found in stone walls and roofs. Tardigrades are most common in moist environments, but can stay active wherever they can retain at least some moisture.

Tardigrades are one of the few groups of species that are capable of reversibly suspending their metabolism and going into a state of cryptobiosis. Several species regularly survive in a dehydrated state for nearly ten years. Depending on the environment they may enter this state via anhydrobiosis, cryobiosis, osmobiosis or anoxybiosis. While in this state their metabolism lowers to less than 0.01% of normal and their water content can drop to 1% of normal. Their ability to remain desiccated for such a long period is largely dependent on the high levels of the non-reducing sugar trehalose, which protects their membranes.

Tardigrades have been known to withstand the following extremes while in this state:

* Temperature — tardigrades can survive being heated for a few minutes to 151 °C or being chilled for days at –200 °C, or for a few minutes at –272 °C. (1 °C warmer than absolute zero).[11]

* Pressure — they can withstand the extremely low pressure of a vacuum and also very high pressures, many times greater than atmospheric pressure. It has recently been demonstrated that tardigrades can survive the vacuum of open space and solar radiation combined for at least 10 days.[12] Recent research has notched up another feat of endurance: they can withstand 6,000 atmospheres pressure, which is nearly six times the pressure of water in the deepest ocean trench. [13]

* Dehydration – tardigrades have been shown to survive nearly one decade in a dry state.[14] Another researcher reported that a tardigrade survived over a period of 120 years in a dehydrated state, but soon died after 2 to 3 minutes.[15] Subsequent research has cast doubt on its accuracy since it was only a small movement in the leg.[16]

* Radiation — as shown by Raul M. May from the University of Paris, tardigrades can withstand 5,700 grays or 570,000 rads of x-ray radiation. (Ten to twenty grays or 1,000–2,000 rads could be fatal to a human). The only explanation thus far for this ability is that their lowered hydration state provides fewer reactants for the ionizing radiation.

Recent experiments conducted by Cai and Zabder have also shown that these tardigrades can undergo chemobiosis — a cryptobiotic response to high levels of environmental toxins. However, their results have yet to be verified.[17][18] In September 2008, a space launch showed that tardigrades can survive the extreme environment of outer space for 10 days. After being rehydrated back on earth, over 68% of the subjects protected from high-energy UV radiation survived and many of these produced viable embryos, and a handful survived full exposure to the sun.[19]

For more on their space travel, read the blog Tardigrades in Space. (I should point out that the blog is written by the scientists studying the tardigrades, not by the tardigrades themselves.)

Here’s a video of a tardigrade just walking (slowly) along, minding his own business:

Written by Leisureguy

16 September 2008 at 9:47 am

Posted in Daily life, Science

Gillette NEW razor

with 6 comments

The Gillette NEW came on the market in 1930. It continued the drop-shoulder profile of the Gillette NEW Improved from 1921, but with a straight bar that required blades with a slot cut out in the middle—and for a while, only Gillette had those blades. The NEW can be found with two handles, one a hollow handle and one a solid handle (of smaller diameter) with a ball at the end. I prefer the larger hollow handle.

I’ve been shaving through the razors, and for a while here I’ll be shaving with the NEW, since it’s one of my favorite razors, leading me to acquire multiple copies. (They don’t make them any more, you know.)

The Gilllette NEW

The Gillette NEW

Click the photo to enlarge. You’ll note that the open comb comes in two shapes:

Two comb styles

Two comb styles

Click to get a closer look. I somehow like better the longer, turned-down comb, though the two shave equally well.

It’s a great razor—not too mild, not to aggressive. IMHO, every guy should have one of these.

Written by Leisureguy

16 September 2008 at 9:35 am

Posted in Daily life, Shaving

Polar Ice

with one comment

I just go from Fendrihan a jar of J.M. Fraser Polar Ice shaving cream—no menthol, but a lovely fragrance and with the usual J.M. Fraser effectiveness at softening the beard. Excellent lather with the Rooney Style 2, and I picked one of my Gillette NEW Razors for the shave. Smooth and flawless shave, and then Booster’s Polar Ice aftershave, which does have a little menthol. Excellent start to the day.

Written by Leisureguy

16 September 2008 at 8:55 am

Posted in Shaving

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