Ask The Science Experts

What causes the Bubonic Plague and how deadly is it?

The Bubonic plague is a disease of the lymphatic system caused from the bite of an infected flea. The fleas are often found on rodents and seek live hosts (such as humans) when their rodent hosts die. Once established, bacteria rapidly spread to the lymph nodes and multiply. Yersinia pestis can resist phagocytosis and even reproduce inside phagocytes and kill them. As the disease progresses, the lymph nodes can hemorrhage and become necrotic. Bubonic plague can progress to lethal septicemic plague in some cases. Bubonic Plague kills about 50% of infected patients within one week.

What most people reading this were probably searching for is actually the Black Death, a specific incident of a Bubonic Plague epidemic that happened in Europe in the 1340s. At the time of the breakout, the world’s population is estimated to have been about 450 million. The Black Death killed about 75 million, or roughly one sixth of the population on Earth. Compare those figures to today’s population and that would be the equivalent of over 1 Billion people dying from the breakout.

The name “Black Death” comes from the fact that the disease causes symptoms like spots on the skin that are red at first and then turn black. Other symptoms include heavy breathing, continuous blood vomiting, aching limbs and terrible pain. The pain is usually caused by the actual decaying, or decomposing of the skin while the infected person is still alive.

Posted by admin for the best selling toys of 2008 at Atomic Elephant Science & Toy Co. For another interesting read, check out their list of the 10 deadliest insects of all time.

The mitochondrian was first identified at the end of the 19th century by a German pathologist and histologist (tissue researcher) named Richard Altmann. It was given the name “mitochondria” by Karl Benda, a German physician. (1857-1933). [source: wikipedia] Altmann is known for his work involving cell theory and structure. In his study of animal cells, he investigated small granules in the protoplasm of the cell. He called these particles- bioblasts, which he postulated were elementary organisms that had metabolic and genetic autonomy. Today Altmann’s bioblasts are known as mitochondria.

So what are mitochondria?

Mitochondria are the powerhouses of the modern cell, providing some 90% of the energy needed for survival. In 1963, scientists discovered mitochondria had their own DNA, arranged in circles, containing the blueprints for 37 of the molecules mitochondria need to create to generate energy.

The single-cell embryo that results from the merger of the egg and sperm has a solitary nucleus with a matching set of chromosomes with about 100,000 genes from the sperm and 100,000 from the egg. These are coded in about three billion base pairs along the strands of DNA.

The fertilized egg, and all of its descendant cells, divide their chromosomes into two mirror images and then split into new cells with each cell obtaining a full set of genes.

By comparison, the DNA of mitochondria has only 16,569 base pairs and these are all inherited from the cytoplasm of the egg. The male makes no contribution to this complement.

Making Fuel for the whole body

Each mitochondrion has a convoluted inner membrane, like a giant nucleus, within its smooth outer membrane. It generates energy by relaying electrons along a series of proteins embedded in the inner membrane. This series is called the respiratory chain. The electrons interact with oxygen and protons to form water and energy.

Mitochondria direct the energy released from the oxidation of hydrogen to pump protons across the inner membrane. This creates a charge and chemical differential that facilitates the synthesis of ATP Synthase which in turn facilitates the creation of ATP (adenosine triphosphate). ATP is liberated into the cell cytoplasm and distributed throughout the body as fuel for all cellular activities.

The process depends upon a steady supply of oxygen and hydrogen (H+) as well as electrons supplied from food. Should any of these be in short supply, the cells rapidly run out of fuel and die. Should mutations inhibit the process of ATP production, the cells begin to weaken.

Source: Wikipedia and This Magic Sea. Posted by the science toy guy for the best selling Christmas toys of 2008.

The abacus that we know of today first appeared around 1200 A.D. in China. No one particular person or group is considered to be the inventor as it likely evolved from various counting boards and bead systems over several centuries. The Chinese call this standard abacus a suan-pan. On each rod, this classic Chinese abacus has 2 beads on the upper deck and 5 on the lower deck (henceforth this type abacus is sometimes called a 2/5 abacus.) The 2/5 style survived unchanged until about 1850 at which time the 1/5 (one bead on the top deck and five beads on the bottom deck) abacus appeared.

Around 1600 A.D., use and evolution of the Chinese 1/5 abacus was begun by the Japanese via Korea. In Japanese, the abacus is called soroban. The 1/4 abacus, a style preferred and still manufactured in Japan today, appeared about 1930. The 1/5 models are rare today and 2/5 models are rare outside of China (except in some Chinese communities throughout the world).

It is thought that early Christians brought the abacus to the East (note that both the suan-pan and the Roman hand-abacus have a vertical orientation). Aspects of Roman culture could have been introduced to China as early as 166 A.D, during the Han Dynasty, as Roman emperor Antoninus Pius’ embassies to China spread along the Silk Road.

There have been recent suggestions of a Mesoamerican (the Aztec civilization that existed in present day Mexico) abacus called the Nepohualtzitzin, circa 900-1000 A.D., where the counters were made from kernels of maize threaded through strings mounted on a wooden frame. There is also debate about the Incan Khipu— was it a three-dimensional binary calculator or a form of writing? (q.v. Talking Knots of the Incas).

Source: Ryerson University Department of Electrical and Computer Engineering. Posted by admin for the science and educational best selling toys of 2008.

In short, a liquid’s boiling temperature is dependent on its composition and the atmospheric pressure on the boundary between the liquid and the air above it. For water, the boiling point at sea level is 100 degrees Celsius (212 degrees Fahrenheit). The atmospheric pressure is roughly 29 mmHg at sea level, but this number is dependent on altitude and is lower the higher you get from sea level.

Boiling is the process in which the molecules in a liquid have enough energy to overcome the opposing pressure of the atmosphere. When these liquid molecules start turning into gas molecules, we say the liquid is boiling. If you lower the opposing pressure, there will be less resistance to the water molecules turning into gas molecules and entering the air, and the liquid will boil at a lower temperature.

It follows that water would boil quicker on a day with lower atmospheric pressure than on a day with a higher pressure. This is true although the difference in barometric pressure on any given day at the same altitude isn’t as great as a change from differing altitudes.

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Most scientists estimate the time between the Big Bang and current day somewhere between 13 and 20 billion years ago. Estimates are derived from Hubble’s Constant, a rate of expansion ratio calculated by dividing the speed at which a galaxy is moving away from the Earth by it’s distance from the Earth. Read the rest of this entry »