Monday, August 23, 2010

The Prodigal Returns

and leaves you wondering what the heck he was thinking. {*grin*}

I finally got a chance to look at my Google Reader today - only 937 unread posts! For those whom I owe a comment or two, the reading and subsequent commenting is in progress. Be patient.

This is a busy season. The garden has been going wild with cantaloupe and muskmelon and Honey Dews. So every few days I  wade through the melon patch picking the ripe ones before they get too ripe and literally explode. But boy are they tasty!

I'll leave you with the mental image of me gobbling cantaloupe with every meal and this odd thought. The other night I was listening to a German radio station via the net and it brought forth the memory of constructing my first radio - a tube and transistor hybrid shortwave set from a kit. That let me listen to the world, intermittently and weather permitting. Now all I do is choose my station from amidst thousands to play with great fidelity via my computer. Yet I still miss the thrill of finally tuning in that elusive show after weeks of trying. The really odd thought is how much hidden technology has to function perfectly for me to listen to the station over the net. More and more what once was hard becomes easy - but it depends on a boatload of invisible technology to work. What is going to happen if the technology ever fails in a big way?

Monday, August 16, 2010

One Of Those Days

Today has been one of those days.

L headed back to the mountains this morning, which is always a bit sad.

The person working on the entry form for the Humane Society 5K Run and Pet Walk is no longer working for the hosting company. Of course I find out by the receptionist telling me over the phone that he is no longer with the company. At least it makes some sense for why it was taking him so long to get the form ready. I just wish they had let me know before it became a critical item on the event timeline.

Severe thunderstorm warnings started coming in by 2pm. By 3pm it was pouring rain. By 4:30pm, the alert sirens were wailing away with flash flood warnings. And of course it was then that the lightning started hitting nearby. Some of the bolts hit only a few hundred feet away and made such a boom that I literally leaped from my chair. (And of course Molly hasn't gotten even an inch away since the thunder began.)
And now, even as I write, patrol cars with loud hailer at full volume are driving up and down the streets announcing "We are under a tornado warning. Seek shelter now."

I think I'll go hide under the bed and sleep until tomorrow. Sounds a lot more appealing than the day has been so far.

(And no, the picture is not mine - it is by Fred Smith and appeared in Meteorology News)

Friday, August 13, 2010

Odd Facts for the Paranoid

Given that today is yet another occurrence of Friday the 13th, it seems like a good time to apply some mathematical legerdemain in support of the true specialness of Friday. Why do I say Friday (and Friday the 13th) is a special kind of day?

Consider these two little known facts:
  • Friday is the most likely day to be the 13th.
  • The first day of a new century can never be a Friday.
No other day can make such claims! How can such outrageous claims be true? Let us begin by considering how our calendar works.

Every fourth year is a leap year, so in 400 years there are about 300 years that have 365 days, and 100 years that have 366 days.

Except...

Every 100th year is not a leap year, so that makes 304 regular years and 96 leap years.

Except...

Every 400th year is a leap year (which is why 2000 was a leap year), so we have 303 regular years, and 97 leap years.

That's all the exceptions.

Thus the number of days in 400 years is given by
(303 x 365) + (97 x 366) = 146,097,
which is an exact multiple of 7, namely 7 x 20,871. That means the calendar repeats itself exactly, leap years and all, every 400 years.

Now all we have to consider is the 400 year cycle. In 400 years, there are 4,800 days (400 x 12) labeled with the date of the 13th. But, 4,800 is not evenly divisible by 7. Thus the frequency of the day of week of the days labeled the 13th cannot be uniform. This is one of those cases where actually enumerating the days and counting them up is the simplest way to get the number of Monday the 13th ... Friday the 13th ... Sunday the 13th's. For the moment, trust me that the answer for the 400 year cycle is[1]:


DayNumber of Occurrences in 400 years
Sat684
Sun687
Mon685
Tue685
Wed687
Thu684
Fri688


So we see that Friday is indeed the day most likely to be the 13th, edging out Sunday and Wednesday by one occurrence per 400 years..

Working out that the first day of a new century is never a Friday (or Sunday for that matter) is much simpler.

There are 365 days in a common year. Dividing 7 into 365, we get 52 plus a remainder of 1. So a common year is exactly 52 weeks plus one day. Therefore, from a common year to the following year, New Year's Day advances by one day of the week (DOTW, since us scientists cannot live without acronyms.). So if New Year's Day of a common year falls on a Monday, the next year's will be a Tuesday.

For a 366-day leap year, the remainder is 2, which means that going from a leap year to the year following, New Year's Day advances by two DOTW – e.g., from a Monday to a Wednesday.

What happens to New Year's Day over a period of several centuries?

In a single century, New Year's Day advances by 100 DOTW (one per year) plus an extra day for each leap year. These come every four years, of course, except that a year evenly divisible by 100 isn't a leap year. Therefore in each century there are 24 extra leap days (100 divided by 4, minus 1), meaning that from one century to the next, New Year's advances by a gross total of 124 DOTW. But each complete week's worth of days doesn't do anything to advance New Year's – seven days of DOTW advancement just gets you back to the day you started on – so we divide 7 into 124 and get a remainder of 5. Thus from one century to the next the net DOTW advancement is five days.

As a second century goes by, the DOTW advances another five days, for a total of ten days from the beginning of the first century. Taking modulo 7 of 10, we get three days of net DOTW advancement over the 200 years.

A third century advances New Year's another 5 days, for a total of 15 DOTW; modulo 7 of this yields 1 day of net DOTW advancement.

For the fourth century, we have to take into account the third leap year rule: years divisible by 400 do have a leap day. So for the fourth century, we advance the DOTW another five days plus an additional leap day, plus the 15 days accumulated over the first three centuries, for a gross total of 21 days advanced. Take the modulo 7 of that, and you get a net total of 0: that is, the fifth century starts on the same day of the week that the first century did. Then the pattern starts over again.

So we have is one fixed pattern that repeats itself exactly every 400 years. Since there are only four starts-of-the-century in each four centuries, New Year's can fall on only four of the seven days of the week. The winners depend solely on where the days of the week happened to line up with the cycle when the crazy leap year system was adopted. Our system is set up so that not only Sundays get left out, but Tuesdays and Thursdays as well. The first New Year's of each 400-year cycle falls on a Friday, the next century starts on a Wednesday, the next on a Monday, and the next one – the century beginning with a year that's divisible by 400 (like, e.g., 2000) – starts on a Saturday.

But you have to remember one little pedantic factoid - the new century technically starts in the the years ending with 01. If you define your centuries as beginning with the year ending in 01, then the cycle goes Saturday-Thursday-Tuesday-Monday. So being pedantic still won't get you a century that starts on a Sunday, but it does get rid of Friday. {*grin*}


[1] If you don't want to trust me about the frequency of the various days of the week over the 400 year cycle, consider this simple Excel spreadsheet calculation as elucidated by Graeme McRae on his wonderful MathHelp site:


... Start with the 13th of this month.  Put that date in cell A1.  Then in cell A2, put the following formula:
=DATE(YEAR(A1+30),MONTH(A1+30),13)
Copy the contents of cell A2 down to all the cells from A3 through A4800.  Now you have a table of the dates of all the 13ths of every month for the next 400 years.

Next, in cell B1, put this formula:
=MOD(A1,7)
Copy that formula from B1 down to all the cells from B2 through B4800.  Here, numbers from 0 to 6 represent the days of the week, as follows:
NumberDay
0Sat
1Sun
2Mon
3Tue
4Wed
5Thu
6Fri
If you like, you can have Excel format these cells to show the day of the week instead of just the number.  Click Format, Cells, Custom, and type ddd as the custom format -- it's up to you.
Now, in cells C1:C7, enter the numbers 0, 1, 2, 3, 4, 5, 6 in a vertical column.
In cell D1, enter the following formula, but don't hit enter yet!
=SUM(IF(B$1:B$4800=C1,1,0))
After you type the formula in cell D1, hold down the Shift and Ctrl keys, and press enter.  This makes the formula into an "Array Formula", so it counts the number of days in column B that match cell C1.  Then copy this formula from D1 to D2 through D7.
If you format column C to make it show day-of-week (Click Format, Cells, Custom, and type ddd), then you will have a table that looks like this:
DayFrequency
Sat684
Sun687
Mon685
Tue685
Wed687
Thu684
Fri688

Monday, August 9, 2010

Serendipity and Other Oddities

I was hit over the head with a clear case of serendipity on Saturday evening. I was sitting at my computer, contemplating what to fix for supper when my phone rang. The conversation that followed had certain Kafkaesque properties.

Me: Hello.
Mom: What time are you coming over for supper? It's getting late.
Me: I didn't know I was coming over for supper.
Mom: Oh, well maybe we didn't actually discuss supper. It was when we talked about you coming over to do some gardening today.
Me: Well, I didn't come over this morning because of the rain last night. But what is this about supper?
Mom: I thought we'd agreed that you were coming over for supper tonight.
Me: I don't remember that discussion, but I was just sitting here contemplating what to fix for supper when you called.
Mom: Well, you'd better get over here. I have the zucchini patties almost done and the steak ready to toss in the iron skillet.
Me: Okay, I'll be right over.

Do you ever have the solution to your quandaries appear out of the blue like that?  Isn't it neat when it does? (Thanks, mom!)

Time to get back to comforting Molly. The thunder and lightning has had her spending all afternoon and evening glued to me. The earlier lightning storm was strong enough to blow out the local cell towers. It only took them a couple of hours to get cell service back up and running. (One of the advantages of fiber optics to the door is that lightning is not a problem. So I could surf and email the whole time.) Now it is just putting up with the continuous warnings for the severe thunder storms and the tornado warnings blaring over all the TV programs. Makes TV seem really boring and pointless. Maybe it is time to go watch TV online. {*grin*}

Tuesday, August 3, 2010

Thumper Attacks!

Tonight Molly and I got started on our walk a bit late - we had to wait for me to go fix mom's electricity. For some reason she gets a little perturbed when her kitchen outlets and refrigerator quit working. {*grin*}

As Molly and I walked along, we passed near a stand of bushes. Suddenly there was the boom and squeals that signal the upset presence of a wild rabbit. Sure enough, there about 2 feet in front of us was a rather large doe working to get us to follow her. It has been hot and dry around here, so I suspect she moved her family to the bush near an irrigated lawn to solve the heat and water problem. In any case, she didn't want us to linger near the bush and was trying hard to decoy us into following her.

Molly was all in favor of a policy of hot pursuit. Nothing like a big squealing rabbit right in front of your nose to get you excited if you are a dog. I had to explain to Molly that if she actually did catch up to the doe, she would probably suffer grievous injuries. The first thing the doe would do is flop onto her back and use those big paws and strong back legs to break Molly's nose and then attempt to rip off her face, followed by sprinting away while Molly was distracted by the pain. I don't think Molly really believed me, but she was willing to continue on with our walk. Good enough. After all, some wild rabbits around here are really big:
(You can read all about this rabbit here.)

The rest of the walk was pretty uneventful until we started back to the house. The entire sky from horizon to horizon in the west was being lit up by lightning, fast approaching us. Which was pretty amusing given that looking in the other direction you could see the stars in the clear sky. Now if some of it would just yield some rain.

Time to go protect the garden from big bunnies. {*grin*}

Monday, August 2, 2010

That Was The Week That Was

Am I the only one here old enough to remember that TV show? (Even I remember it only from reruns on late night TV; it originally aired on the BBC way back in the early 60's. I seem to remember seeing it as late night filler on a Boston UHF station in the 70's.) In any case, it supplied a catchy title so the memory space it occupies in my mind is not totally wasted. For the insanely curious, go read the Wikipedia synopsis at That Was The Week That Was.

Last week I mentioned that I would write about the beautiful printer/scanner I won from the wonderful ladies of Aiming Low and HP. Late last week I finally got it unpacked and set up. (My delay was making it dangerously close to losing my tech geek card - true geeks must drop everything to play with any new piece of equipment!) Setup was trivial since it has built in wireless connectivity. And the photo prints are spectacular! Thank you Aiming Low and HP! Oh, it also looks pretty nifty as well:
Nothing like all black with a neat little touch screen to appeal to the tech geek in me.

L was home this weekend and we had the big thirtieth birthday party for my friend the writer to attend. A group of friends, great BBQ, two kinds of cake, and pie - the ideal way to say happy birthday. It doesn't seem possible that he is that old. I have known him since he was in high school and it just doesn't seem to be that long ago. (I suspect that is a symptom of aging - everything seems to have happened just a moment ago. When you are young, it seems like everything is yet to happen in the far distant future. The older you get, the faster things seem to happen.) In any case, Happy Birthday Bryson!

Time for Molly and I to head out for our walk. I think Molly will trust me by now. This morning it was time for her annual veterinary checkup and vaccinations.  She and I hopped in the truck went to the bank where the drive up clerk gave her a doggy biscuit. Molly thought that was pretty neat. Then we drove out to the clinic and Molly could smell all the dogs and cats and other critters in the gravel parking lot. That really excited her. She led me in the doors and sat with me in the waiting room. But when it came time to sit on the scale and she really didn't want to be still. But we got through it and into the exam room.

That was when all those things that she blames me for happened. The cold stethoscope to the chest, the thermometer up the rear, and of course the three shots. All while I am holding her against my chest and beginning to look like I sprouted a white fur coat from her shedding on me. We came home and she carefully spent most of the day sleeping across the room from me in my office, raising her head to be sure I wasn't up to another sneaky trick whenever I moved. By this evening she was willing to let by-gones be by-gones and was rubbing furballs all over my legs. So I think it is time for us to go. {*grin*}
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