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Sunday, April 29, 2012

Oro verde

Travel can be unexpectedly educational and our trip to Costa Rica in 1992 is a case in point. We knew little about the country and so on arrival, as we often did, we went to the National Tourist Bureau in San Jose for information.  When we learned there was a tour called ‘Oro Verde’ [Green Gold] that could be taken into the one of the National Parks in the northeast bordering on the San Juan River and Nicaragua, we were keen to sign up – see map on the left.

The tour was run by Germans and, in spite of the fact they needed a break after taking care of a large group of Europeans, we persuaded them to take the two of us with them when they went back to regroup. Our first stop was at a depot camp where they had an office and kept supplies.  While we waited, we explored the grounds and were surprised to discover the rusting hull of a fairly large vessel.

Our curiosity was assuaged on the last lap of our journey into the jungle to the camp on the south bank of the San Juan River. We learned that during the California gold rush of 1849, Cornelius Vanderbilt established a cheap, reliable way for prospectors on the east coast to travel to the gold fields of California by traveling up the San Juan River in steamboats, sailing across Lake Nicaragua and then being transported overland by stagecoach to a waiting ship that took them up the Pacific coast to San Francisco. Once established, the route could handle 2,000 passengers a month at a fare of $300. Comparing this sea route to the long hazardous overland trip across the continent in covered wagons, it is no wonder that business was brisk and made Vanderbilt a 'pretty penny'.  I have since learned that this route linking the Atlantic to the Pacific Oceans once vied with Panama as a choice for the great Canal.

We arrived at the camp at sundown, mixed with the workers and guides as we ate an evening meal, and eventually were bedded down under mosquito nets. At dawn we were awakened by the incredibly loud roar of howler monkeys  and, not having been forewarned, we could have been terrified but for our sturdy cabin and the stirrings of our hosts.

We spent an interesting and happy few days at the camp - every morning watching as a boat on the river stoped at each small wharf to pick up children. They were being ferried to school that was compulsory for all even in this northern wilderness. Sometimes we had a guide who spoke English and on our first walk with him, he showed us a huge tree that was an example of others like it that the Germans had bought to prevent it from being cut down for timber. As we tramped around in the dense forest and he pointed out tiny red frogs and other creatures and plants strange to us. It was an unforgettable experience and we decided in the end that the ecotourism we enjoyed was aptly named ‘Oro Verde’.   Rie 

Sunday, April 22, 2012

Gyroscopic Effect

Our neighbor’s child who must be just 4 or 5 years old, has a small two-wheeled bike and I was watching today as his father was helping him learn to ride it.  His dad must be aware of the gyroscopic effect  because if you click on the video it shows how he got his boy moving fast enough so the bike wheels were like gyroscopes and had a strong tendency not to tip over.  The gyroscopic effect is somehow peculiarly non intuitive, perhaps because we don’t play with spinning wheels ordinarily and so we’re not used to the fact that any spinning disk tends to continues to spin in the plane in which it is spun and it takes considerable energy to move it out of that plane.

A really neat way gyroscopes are used nowadays is in Segways. They have gyroscopes spinning in their wheels that keep them vertical when you ride one and also the gyroscopes are involved in steering.  Riding a Segway feels like nothing you've ever experienced.  As the video shows,    to increase your speed, you just push the handles forward and then pull back to stop or go backwards.  To turn left or right you use the handlebars like a bike.

It was in the late 1920s that gyroscopes were used to control a ship's roll, first for warships and then in passenger liners. As you’d expect, the heavier the disc is and the faster it is moving, the harder it is to tip it over so gyroscopes on ships weigh tons and they are kept spinning with motors.

In airplanes and helicopters, besides the fact that gyroscopes give them stability, they are essential because, if there is poor or no good view of the ground, the pilot depends on the horizontal position that the gyroscope maintains to tell whether the plane is climbing, diving, or banked left or right. 

Gyroscopes are also tremendously important now for world communication systems because they can keep stationary satellites oriented precisely in a specific direction so they can receive signals from a transmitting station on Earth and then redirect it to a receiving station in another part of the globe. Some of the more than 3,000 satellites now in orbit handle all long distance calls on cell phones as well the important Global Positioning System [GPS] so much counted on now to direct travelers to their destinations.  
The famous Hubble telescope that orbits the Earth, often must use very long exposure times to capture the spectacular pictures of galaxies in deep space. That means it has to be extremely stable to keep the telescope precisely pointed for extended periods of time and, for that reason, there are 6 of the best kind of gyroscopes in the world on board to do the job.  As you can see from the picture of the telescope, it has solar panels that supply the electricity that is needed to keep the heavy gyroscopes spinning very fast.

I find it fascinating that simple spinning discs are used to make so many useful and important systems possible and I hope you do too!   Rie 

Sunday, April 15, 2012

Mirror Therapy

This has been a difficult week. My younger sister, who lives too far away for me to visit easily - has had a stroke and is in hospital recovering. Her left side has been affected and particularly the use of her left arm and hand. This blogpost is for her and others like her in that it describes a type of therapy that often is able to help patients in similar situations to recover even if their condition is complete paralysis and has not been treated for years.

The picture on the left above shows the patient in the centre who has two therapists working with her. The patient’s view is shown in the picture on the right. She is instructed to look only at the reflection in the mirror that looks exactly like her affected limb – especially if any rings or a watch has been removed. If she does simple exercises with her good hand while attempting to do the same thing with her affected hand behind the mirror, neural pathways in the brain seem to be stimulated into helping the affected hand actually learn the same simple movements. The technique requires daily repetitions over weeks or even months but in many cases, studies show that it helps patients regain use of the affected limb.

If you click on the video link, you will see Doug, a stroke victim who actually has paralysis of his left arm and hand, learn how a mirror box may actually be starting to help him probably after many months of disuse. Another patient remarked that, “all my other methods of therapy exercise my muscles, the mirror is the only one which exercises my brain and nerves”. The box Doug uses may be purchased on line but you can easily make one using a cardboard carton and taping a mirror to one face of it as shown in the picture on the left. A mirror tile can be used for the purpose and may usually be bought at a hardware store – it is important that it is a good mirror and does not have any distortions
Dr. Vilayanur Ramachandran, a pioneer in the study of the brain, was the originator of the use of mirrors to help patients not only with paralysis caused by stroke but also those who had phantom pain in amputated limbs, arthritis in only one hand, carpel tunnel pain or complex regional pain syndrome [CRPS].
We are all right or left handed and I’ve read that learning to be ambidextrous increases neural circuits that connect the right and left hemispheres of the brain and can be helpful in many ways from increasing sports skills to playing music. I’ve been thinking of trying out a mirror box myself and out of curiosity to try to stimulate my brain to make it easier to learn to use my left hand.     Rie

Sunday, April 8, 2012

Road Scholars

It all started with a free spirited, middle-aged back packer, who used to knock around Europe staying at Youth Hostels. When he was traveling in Scandinavia he was struck by how active older people were there, 60, 70 and even 80 year olds. When he got back to the U.S.he enthused about his experiences to a friend, a university administrator, and between them they came up with the idea of creating Elder Hostels, using inexpensive university student accommodation during the long summer break when they were free. They also involved faculty members to give in-depth lectures about the history and special feature of an area in the mornings and arranged for guided course-related excursions to sites of interest in the afternoons.

The program took off and within 5 years it started to expand to include year-round trips that are now offered in 150 countries. Accommodation changed to staying in good hotels but the agenda still included morning lectures, often at the University, and afternoon field trips. The name Elderhostel was no longer fitting and, though it took a while, the program is now appropriately called ‘Road Scholars’.

We have joined several Elderhostel overseas programs but the first lecture on our schedule in Egypt was particularly memorable. I cite it because although I had visited Egypt before, it gave me a new perspective on why Egyptian civilization was so different and seemed to be so unaffected by other cultures in the region. The lecturer immediately made it clear when she drew our attention to how isolated the Egyptians were in its earliest millennia. The country is surrounded on three sides by deserts, the harshest and most dangerous in the world, and their northern coast had shallow water and sandy beaches with no natural ports. The lighthouse at Alexandria, only completed in 247 BC was built to light the way for sailing ships navigating the tricky harbour there and was one of the seven wonders of the ancient world.

Because of the natural barriers that isolated them, it was virtually impossible to invade Egypt so, except for internal struggles, it had a peaceful history for the most part and, as is clear when you look at the map on the right, the fertile Nile river valley not only made it easy to unify its people but provided the water for a plentiful and stable food supply. The result was that Egyptians developed their own unique hieroglyphic script, complex religious beliefs and colossal monuments. It is a truly fascinating country to visit especially with the guidance of road scholar lecturers! Rie

Sunday, April 1, 2012

Heat Pump

When we visited Iceland in 1997, we rented a car and did some exploring of the area around its capital, Reykjavik. The picture shows the kind of thermal activity we encountered and it made me aware once more that underneath the Earth’s crust is a layer of molten rock that is about 9000 Celsius. Usually that crust is from 30 km (20 mi) to 50 km (30 mi) thick but under western Iceland it is much thinner and responsible for the thermal pools and steaming cracks. The people of Iceland take full advantage of the available heat by extracting the geothermal energy for warming greenhouses, producing electricity and heating their homes.

Even with the thick crust we have under us, there is plenty of geothermal energy available because the deeper you go in the ground, the warmer the temperature gets. Where we live, if you only go down 6 feet the ground temperature is a constant 70 C [44.60 F] summer or winter.

In the summertime when the air is 320 C [900 F] or warmer, the relatively cool ground water can be circulated in coils and air blown over them to cool a house. Fans use little electricity and this system is much more efficient than any air conditioner.

In the winter when the ground water is relatively warm, you can extract that heat using a refrigerator unit. If you think of what a refrigerator normally does you realize it is actually a ‘heat pump’, taking heat out of warm food you put in it and sending the heat out its back and into the room. So - you pump water at 70C into a coil in a refrigerator unit, the ‘frig’ then cools the water to 2 or 30 and the heat removed is released out into your house and the colder water is sent back down into the earth.

If you live in the country and get water from a well, you can just circulate well water through a refrigeration unit to extract heat but on a serviced city lot, coils of plastic pipe must be laid in trenches as shown on the right. The initial expense of laying the pipe is amply paid back in energy saved. Compared to other alternate forms of ‘green energy’, a geothermal (ground source) heat pump is the most popular because it is so predictable and cost effective.

There is enough energy stored under your house to more than supply its heating and cooling needs. When compared to an electrically heated or cooled home, geothermal heat pumps use less than 1/3 the amount of electrical energy needed to heat your home and savings are much greater than that to cool it. Well worth considering especially if you're building a new house. Rie