Dan's Outside

How DEET Works

The most common (and only effective, in my view) mosquito repellents are based on a chemical known as DEET. As is sometimes the case with things like this, apparently scientists have known that DEET does work, but did not know why.

The old theory was, as I understand it, that DEET somehow “jammed” the mosquitos’ sensory system in a way that made it impossible to detect human skin. This sort of makes sense if you have ever observed how mosquitos respond to normal skin and DEET treated skin: in the former case they land and chow down; in the latter they may get close but they don’t usually even land. (The buzz still annoys the heck out of you, but at least you aren’t getting bitten.)

New research suggests a simpler process is going on. Basically, DEET smells bad to mosquitos so they avoid it.

While I’m on the DEET subject, a few other points based on my own experience. You may already know some of this, but perhaps the info will be useful to some who don’t.

“Back in the day” a lot of people got the “100% DEET” (or nearly 100% DEET) versions of the repellent, on the theory that the stronger the solution the better it would repel the little bloodsuckers. Turns out that this wasn’t quite right. It only takes a little bit of DEET to work effectively – and the 100% solution tended to go on way to strong is some places and not distribute to well to other places. Eventually manufacturers and users figured out that a lower percentage of DEET in a spreadable creme would work more effectively.

I haven’t been keeping careful track of these things, but this year when I bought a new supply I found several products that claim to be long lasting or to release slowly over time. This makes sense, as even in the dilute creme form the repellent sometimes seemed to wear off too quickly. From what I can tell from the newer versions that I’ve used this summer, there really is something to the claims of longer lasting protection.

Finally, DEET is poisonous to humans. Don’t overdo it, and do be careful about ingesting the stuff. Many years ago I made this mistake and the results were not pleasant. We encountered truly awful mosquito conditions at Booth Lake in the Yosemite high country – so bad that we slathered on the DEET (in the old, undiluted form) and mostly tried to stay in the tent. The problem occurred when we had burritos for dinner – as we handled and ate this dinner we apparently transferred some of the DEET to our mouths, and the result was not fun.

August 18, 2008 Posted by gdanmitchell | Commentary | Comments Off on How DEET Works

So, Why NOT Drill More?

The election season has begun to bring the usual set of invented issues chosen by the candidates and their handlers to differentiate them from their opponents. My view is that the call for opening the arctic and offshore areas for more drilling is really more about that than about “solving the energy crisis.” Why?

1. The oil companies are not now using all of the oil exploration and drilling areas that are currently open to them. If they aren’t using those that they have access to now, why would we expect them to expand their extraction to even more areas?
2. As has been pointed out many times, if the areas under discussion were “opened” and the oil companies actually did begin the process leading to oil extraction, it would be something like a decade before any of this oil actually entered the market, and the decrease in oil costs would likely be a few cents per gallon… and a time when the price of fuel will undoubtedly be much higher than it is today. In other words, “too little and too late.”
3. And even then the supply of oil is finite. We can put off the time when we must develop alternatives, but that day will definitely arrive.
4. Our energy problem is not simply a problem of “not enough oil,” and the increased price of oil provides a good old fashioned free market incentive to move towards making better use of the alternatives, which will now be more financially viable in relationship to oil. Government incentives for developing these alternatives would do us far more good in the long term.
5. If waving of a magic wand would suddenly produce an unending supply of cheap oil, we would still have to deal with the very serious problem of increasing CO2 levels from burning that oil. In other words, even with plenty of cheap oil available, we would still need to greatly diminish our use of it… and soon.

July 30, 2008 Posted by gdanmitchell | Commentary | 3 Comments

'Telegraph' Fire Near Yosemite

I don’t have any first hand info about the fire since I’m not in Yosemite, but reports I’m hearing (from a variety of sources ranging from newspapers to people who are there) includes:

• The route from Merced/Mariposa that follows the Merced River past El Portal is now apparently closed due to the fire. (The more southerly route 41 and the northern route 120 remain open and should not be affected.)
• I hear that there has been an increase of smoke and ash in the valley.
• Apparently the power was cut to Yosemite Valley, though reports are that generator power is keeping stores and restaurant and other accommodations open.
• As of this evening, none of the Yosemite Webcams seems to be updating, probably as a result of the power issues.

July 28, 2008 Posted by gdanmitchell | Commentary | 3 Comments

A REAL Outside Guy

Seen, of all places, at oboeinsight*:

And He Makes Violin Bows

I know my husband, Dan, will enjoy reading about him, too.
English concedes that he is slowing down, that the mountains are steeper than they once were. For his 90th birthday, he vows to make the hike out carrying 40 pounds.
– Patty [oboeinsight]

Read the fascinating article here

*My wife’s oboe blog.

July 27, 2008 Posted by gdanmitchell | Commentary | 2 Comments

OK, just a bit of politics

One of my local online “newspapers,” apparently attempting to provide fair and balanced coverage of the two presumptive presidential candidates, posted the following articles about McCain and Obama today:

• 200,000 Cheer Obama In Berlin – Presumptive nominee calls on Europeans and Americans to work together.
• McCain visits German restaurant — in Ohio

July 24, 2008 Posted by gdanmitchell | Commentary | Comments Off on OK, just a bit of politics

Bush: What Is He Thinking?

Several bits of Bush News today.

First, seen in may places is the following news:

Bush Acts on Drilling, Challenging Democrats. President Bush lifted nearly two decades of executive orders banning offshore drilling for oil and natural gas, while a Congressional moratorium on drilling remains in place. [NYT > NYTimes.com Home]

Does anyone really see this as anything more than a wedge issue for the upcoming presidential election? It won’t make a bit of difference in the price of oil/gas, the oil companies are already not making use of all the currently available exploration and drilling leases, and the environmental costs are tremendous.

I listened to a good part of Bush’s press conference this morning. Hearing him get lost, forget what question he had just been asked, mumble embarrassing asides between answers, utter many sentences that either made absolutely no logical sense and/or exactly contradicted the point he was trying to make, repeat irrelevant “boilerplate”… am I the really only one who wonders – political differences aside – about his basic competence as President?

If you wonder what I’m talking about, find a moment to listen to a bit of today’s press conference. Frankly, I’m not sure whether the appropriate description is “sad,” “pathetic,” “embarrassing,” or “scary” – or all of the above.

July 15, 2008 Posted by gdanmitchell | Commentary | 2 Comments

Thinking About Sleeping Bags – How Light is Too Light?

When I return from a pack trip I often reflect a bit on how my equipment did and did not work, and on how I might tweak my setup. One issue that always concerns me – and more so as I get older – is the balance between weight and functionality. This is especially important with core pieces of gear like the sleeping bag.

For the past couple years I have used the excellent Marmot Helium sleeping bag on most pack trips. Marmot uses high quality down and careful design (a half-zipper, for example) to provide a 15-degree bag that weighs only about two pounds and stuffs quite small. This is a fine piece of gear and, along with most other reviewers, I have only good things to say about it.

But do I really need a 15 degree bag for summer backpacking in the Sierra Nevada, where the temperature only very rarely falls to freezing? Not really. Some years ago I purchased an early model of the Marmot Arroyo sleeping bag. (Newer models of the Arroyo are available and appear to have been updated and improved.) This bag also uses the premium, high-lofting down, but it minimizes weight with a fairly tight cut and by minimizing the insulation to the point that it is rated only to 30 degrees.

On this past week’s quick trip into the Young Lakes Basin in the Tuolumne Meadows backcountry of Yosemite National Park I decided to take advantage of warm conditions and use the Arroyo bag again, after having pretty much switched to the Helium for the past couple of summers. And the results? Pardon the awful pun, but I’m going to say it was a mixed bag. Continue reading →

July 12, 2008 Posted by gdanmitchell | Commentary | Comments Off on Thinking About Sleeping Bags – How Light is Too Light?