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Yesterday evening at about 9:00 pm I went to the little
hole-in-the-wall Thai restaurant that is near my place. Well, it's not
actually a hole in the wall--it's more like a palm frond roof with a
few tables under it in the front half, a bar counter across the center,
and the cooking area in the rear behind a woven rattan partition, not a
single wall in the place (but already I digress). I took a table and
sat with my back towards the road.

After ordering a lovely yellow curry with vegetables and steamed
rice (yum), I gazed off to the left, my mind on nothing. Then I saw a
movement along the electrical cables strung between wooden posts.
Thinking it was a squirrel I didn't pay much attention at first, but
the animal was moving uncharacteristically slowly for a squirrel,
carefully lifting one paw, stretching it out ahead, and planting it
precisely before lifting another paw. And it moved each leg
separately--I don't know for sure, but my impression of squirrels is
that they move two legs at once and zip right along the wires.

Of
course, curiosity got the better of me and I had to get up to take a
look at the critter. When I got to where it was, it froze in mid-stride
and simply stared at me with gigantic round eyes surrounded by a
panda-like mask. I could see feet with something like thumbs grasping
the wires, so then I thought it might be some kind of monkey... but
there was no tail! Was it a deformed monkey? Or an Asian version of a
tree sloth?

I asked my host, who told me it's a rare creature
called a "ling-lung"--a forest dweller almost never seen. He rushed off
to get it some food and left me to stare at what I knew to be a living
animal, but which appeared to be part of a static natural history
museum display.

Early this morning I dug around on Google for an
hour and discoverd what it was that I saw. It turns out to be called a
slow loris, or Nycticebus coucang. It is indeed a primate like the
monkey, but in a group called presimian and are more like lemurs
than true monkeys or apes.

Here's a picture I got from the internet (I didn't have a camera with me!)

Moondog's summary of the talk by Louis W. Jankowski, Ph.D. (dive instructor
at McGill University, but not a medical doctor) prompted me to review
the reading I did on the topic for my own PADI instructor certifiction
course.


For those of you who are not dive professionals, I thought it might be
interesting to post links to a couple of articles written by dive
medicine physicians in relation to children's maturation and the risks
of scuba. I am also pasting an extract from PADI's policy on the
medical concerns involving children and scuba.

Caveat: I am not a medical doctor; as a scuba professional I follow my
agency's safety standards. For the purposes of this blog, I am posting
the following as additional sources of information, not as a claim of
personal expertise in human development or pediatric medicine.

So, first the extract, then two links.

Medical Issues Regarding Children Scuba Diving

Speculation and controversy surround the discussion of the medical
implications of allowing children to dive. Divers Alert Network (DAN)
has gathered information on the subject, as have other physicians
versed in dive medical issues, such as Dr. Simon Mitchell, who has
consulted with PADI on the topic and authored an article on the subject
in the Fourth Quarter 1999 issue of The Undersea Journal, which we have
reprinted in this magazine. After a thorough review of the medical
literature on children and diving, DAN concluded that insufficient
clinical or scientific medical documentation exists to make any
evidence-based judgment on the medical implications of allowing
children to dive. Under PADI Standards, children are pre-screened for
dive fitness (under parental supervision) via a dive-specific medical
screen, and are required to be evaluated by a physician should anything
on the screening form be answered in the affirmative.


Bone Development

The body's long bones grow at their ends, called the epiphysis. This
growth process continues until about age 20. In the past there has been
heated debate about the effects of pressure on the epiphysis, and its
potential to stunt growth or cause necrosis. However, there are 1)
Currently no relevant data from testing (animal or human). 2) Data from
clinical reports in cases of decompression sickness in those aged 15-20
have not shown damage to the epiphysis. 3) Exposures would have to be
extreme, such as commercial tunnel divers might experience when under
significant pressure, a scenario well outside the scope of recreational
diving. 4) The limited depth and decompression stress limitations of
junior divers adds a measure of prevention. 5) If this were an issue,
it would apply to any diver younger than 20. While the debate may
continue, the reality of a few decades of thousands of dives performed by
junior divers creates a valid empirical database of experience. PADI
intentionally chose to restrict the depth in our experience and junior
diver programs specifically to minimize decompression stress, thereby
addressing the hypothetical argument head on.


Decompression Illness

It's important to note that PADI does not support deep dives for
10-11year-olds. In fact, PADI standards clearly restrict it. Ten- and
11-year-old junior divers are restricted to a maximum depth of 12
metres/40 feet. With such limited exposure, the risk of decompression
illness is less than minimal. PADI does not support dives conducted
beyond 12 metres/40 feet for 10- and 11-year-old junior divers.


Pulmonary Development

Information from DAN and other medical organizations indicate that
there may be some final formative pulmonary growth until age eight.
This is the reason PADI settled on 10 years as a minimum age for a
restricted certification, and a reason CMAS sets its minimum age for
scuba certification at eight years.


Ears

Eustachian tube dysfunction is common in early childhood, so
susceptibility to ear barotrauma is greater for children under age 12
(when most children have achieved adult-level Eustachian tubes). It is
important to make certain children can equalize properly in confined
water before taking them on open water dives.


Dive Risks In Perspective

Every day, thousands of parents enroll their children in sports such as
soccer, American football, basketball, field hockey, skiing,
gymnastics, skateboarding, bicycling, snowboarding, volleyball,
wrestling, baseball, martial arts and other contact adventure sports
and recreations. The incidence of morbidity and mortality in these
activities is significant. For example, in the United States alone,
emergency rooms treat more than 775,000 children under the age of 15
for contact sports injuries each year. Trauma involving spinal/cervical
injuries, fractures and the like are frequent occurrences in these
sports. The risk/consequence/severity of such activities is clear. In
comparison, scuba diving is a non-contact, non-impact soft activity
experienced under closely controlled conditions requiring strict
supervision, limited depth and instruction. Clearly, scuba is a
reasonably safe activity with manageable risks, but it definitely does
involve risk. The major, potentially catastrophic dive-related risks
for children include drowning, lung overexpansion injuries including
arterial gas embolism, water aspiration and ear injury. These need to
be managed through proper supervision and other precautions, such as
reducing ratios and increased adult supervision. Both of these are
vital requirements in PADI's junior diver programs.

http://www.padimembers.com/members/shared/readingroom/resource_library/news/1Q1992_pg26/

http://www.padimembers.com/members/shared/readingroom/resource_library/news/4Q1999_pg88/

Last February I was with an AOW student at Richelieu Rock, a
semi-submerged seamount (under at high tide out at low) north of the
Similan Islands in Thailand near the Burma border. We knew there was at
least one whaleshark in the area and planned a series of dives to try
to be on the seamount when one paid a visit.

Because they seem to swim around an area in wide loops, we did the dive
near the top of the mount waiting for a signal to indicate someone had
seen an animal. I decided to descend to 17m to a place where there was
something cool and interesting--can't remember what, maybe a harlequin
shrimp, or an ornate ghost pipefish, or a frogfish--but when I got down, I
quite quickly hit my NDL, decided to leave the cool critter for the next dive
and began an ascent. As I started to come up, I looked up, and there was
the whale shark, two meters above me and swimming very slowly. I had nowhere
to go it was so massive! I simply lay down on my back, stopped my ascent, and
he glided right over me, sort of like the image of the big starship Enterprise
coming in for a landing. I also got a shot, but since it's not from the front,
it's not all that interesting

Of course we had another dive at the same site, and the same whaleshark
came back for a visit. We just hung at about 10 m and watched him circle around
and around, at least a dozen times, before we ran low on air and had to go up.

I never did get back down to look for the cool little critter, , but I didn't mind at all!

One of my kids is in the middle of “interesting times” as I sit here
writing this. Just 24-hours ago a 5.4 magnitude quake was centered
about 15 km from his place. Now there’s Hurricane Flossie holding court
just offshore….

So where is this kid of mine? The Big Isle of Hawaii.

(Just breathe, mom… in and out; in and out.)

This is the final part of a four-part blog on tides and tidal currents. Click the links for the other parts: Part 1 Part 2 Part 3

Part 4:

When you decide to dive will depend on the
phase of the moon because if it is full or new, you will want to do
your dive at the "slack tide", which is when the equilibrium between
when the water is at its highest or lowest point, and the hour or so on
either side of that. If you are diving during a quarter moon, the
currents may be weak enough for you to disregard the highs and lows
altogether.

 Try a night dive at slack tide with a full moon for a special treat!

This is the third part of a four part blog on tides and tidal currents. Part 1 is here, and Part 2 is here.

Part 3:

What
causes a tidal current is the DIFFERENCE between the height of a high
tide and a that of a low tide. All the water from a very high tide (at
a new or full moon) has to empty to a very low tide in the same 6 hours
that it takes to empty the water from a not-so-high high tide to a
not-so-low low tide (at the quater moons). The same thing happens when
the tide is filling, or moving from low to high. Of course to move all
that extra water, it has to flow faster! Therefore the tidal currents
run faster during the new and full moons than they do during the
quarter moons. The water takes a while to get up to its maximum speed
and it slows down when the cycle is finishing, so the fastest currents
are right in the middle of the change between high and low.

Click here for Part 4.

I keep getting questions from new-ish divers who want advice about
how to deal with currents. But what they really need to know is how to
plan the day and the hour of their dives so that they don't get caught
in big tidal currents.

So I've written this blog about tides and tidal currents, in four easy lessons.

Part 1:

The
moon is like a big magnet that pulls the water up towards it when it is
directly in line with our part of the world (this is called
gravitational force). When the moon is diametrically opposite or in
line with our body of water, the tide is high because the moon's
gravitational force pulls water away from other parts of the ocean as
it approaches us in its circuit of the earth. Of course, if the moon is
piling water up someplace else (as it departs from our skies), it is
taking water away from where we are, and this becomes a low tide. The
moon circuits the globe every 25 hours, so the high tides are about
every 12 1/2 hours, and the low tides are about 6 1/4 hours later.

Click here for Part 2.

This is the second of a four-part blog about tides and tidal currents. Part 1 is here.

Part 2:

Actually,
the sun also pulls at the water, but since it is so much further away,
the graviational force is weaker. So imagine that when the sun and moon
are in line (new moon and full moon phases) they work together to pull
larger masses of water during high tides, and the tides are highest
during these moon phases. This water has to recede in greater quantity
when the sun and moon move away, of course, and the low tides are
lowest during these phases, too. Contrastingly, if the sun and moon are
working against one another--during the quarter phases--the tides are
much smaller. High tides are not as high and low tides are not as
low.

Click here for Part 3.

In some lyrics about life, the Brazilian singer/composer Toquinho
writes: Nessa estrada, não nos cabe conhecer ou ver o que virá. O fim
dela, ninguem sabe bem ao certo onde vai dar. (It is not for us to
sense or see what lies ahead along this road. Where it will lead us in
the end, no one can ever really know.)

Some people are motivated to choose a path through life designed to
meet the expectations of those around them. Their life choices are
driven largely by external factors. The world needs people like these
because they form a bedrock of stability, predictability, and duty. A
world without safe havens could not survive.

But this kind of external motivation is alien to me. I am internally
motivated. I need to go to the edge of my experience and try to see
what's beyond. And if it's good, I will return to share the wonder of
it and offer to take others along to see for themselves.

A world without the curiosity and imagination of adventurers and risk
takers would never make a discovery (unless forced by circumstance),
would not have art (craft yes, but not art) nor cuisine (as opposed to
cooking), nor music that touches the soul.

I am glad not to know where the road will lead me next. It’s all part of the adventure.

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