Today I Learn

2021-06-26 10:12:50 ​​What is Nuclear Medicine Technology?

Nuclear medicine differs from other diagnostic imaging technologies because it determines the presence of disease on the basis of metabolic changes rather than changes in organ structure.

Nuclear medicine technologists operate equipment that detects and maps a radioactive drug within a patient’s body to create diagnostic images.

The images are then produced on a computer screen or on film for diagnosis by the health care team.

By administering these radiopharmaceuticals to patients they can monitor the characteristics and functions of tissues or organs in which the drugs localize.

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2021-06-24 10:10:09 ​​What Is Alkaline Water?

To put it simply, alkaline water is water that has a higher potential hydrogen than regular drinking water.

The pH level is measured by the amount of hydrogen ions that exists in a given solution. High concentrations of hydrogen ions yield a low pH (acidic substances), whereas low levels of hydrogen ions result in a high pH (basic substances).

The term alkaline gets used interchangeably with basic but they’re not exactly the same.

Alkaline compounds (alkali) are substances, like salts, metals, and minerals, that, when added to water, make it more basic.

Water always contains some amount of dissolved solids including minerals like calcium, magnesium, potassium, and sodium, but alkaline water tends to have a higher amount of total dissolved solids, which increases its pH level.

Regular drinking water is typically neutral with a pH level of 7 and alkaline water is slightly basic with a pH level of about 8 or 9.

The idea that alkaline water is medicinal, curative, and able to bring about optimal health seems to be based on the belief that acidic properties in the body and blood are the cause of ill health and disease and need to be neutralized.

Therefore, a more alkaline body will lead to better health.

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2021-06-24 10:10:06 Open / Comment

2021-06-22 16:23:25 ​​What is Electronic Democracy?

E-democracy (a combination of the words electronic and democracy), also known as digital democracy or Internet democracy, is the use of information and communication technology (ICT) in political and governance processes.

It incorporates 21st-century information and communications technology to promote democracy; such technologies include civic technology and government technology.

It is a form of government in which all adult citizens are presumed to be eligible to participate equally in the proposal, development and creation of laws.

E-democracy encompasses social, economic and cultural conditions that enable the free and equal practice of political self-determination. 

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2021-06-20 16:15:18 Open / Comment

2021-06-20 16:14:51 ​​What is a Geiger Counter and How does it work?

A Geiger counter is a metal cylinder filled with low-pressure gas sealed in by a plastic or ceramic window at one end. Running down the center of the tube there's a thin metal wire made of tungsten. The wire is connected to a high, positive voltage so there's a strong electric field between it and the outside tube.

When radiation enters the tube, it causes ionization, splitting gas molecules into ions and electrons. The electrons, being negatively charged, are instantly attracted by the high-voltage positive wire and as they zoom through the tube collide with more gas molecules and produce further ionization.

The result is that lots of electrons suddenly arrive at the wire, producing a pulse of electricity that can be measured on a meter and (if the counter is connected to an amplifier and loud speaker) heard as a "click." The ions and electrons are quickly absorbed among the billions of gas molecules in the tube so the counter effectively resets itself in a fraction of a second, ready to detect more radiation. Geiger counters can detect alpha, beta, and gamma radiation. Open / Comment

2021-06-20 04:53:28 ​​How does Vacuum or Dewar Flask work?

A vacuum flask or a dewar flask works on the concept of insulation.

A vacuum flask or dewar flask is designed in a way to maximise insulation and limit heat transfer.

Most vacuum flasks have an inner glass chamber, a middle glass or stainless steel layer, and an outer plastic or metal casing.

A tight plastic stopper than can be screwed in or an airtight lid is also provided.

The inner glass chamber is lined with reflective layers and there is a vacuum separating the middle and the outer chambers.

The vacuum flask prevents all three modes of heat transfer by its design, the inner chamber is separated from the middle chamber with a vacuum, preventing convection and conduction, the mirrored layer within the inside chamber reflects any heat being radiated.
Since there is two degrees of separation between the inner and outer layer, there is no conduction.

For example, Let us say boiling water (100°c) is kept in an open vessel in a hotel at room temperature (15-20°c), due to the difference in temperatures, heat travels from the water to its surrounding, and hence the water cools down by losing heat to the environment.

However when the same water is stored in a vaccum flask or a dewars flask, heat transfer is inhibited hence keeping the water hot.

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2021-06-20 04:52:14 Open / Comment

2021-06-18 20:42:04 Why does a magnetic compass point to the Geographic North Pole?

A magnetic compass does not point to the geographic north pole. A magnetic compass points to the earth's magnetic poles, which are not the same as earth's geographic poles.

Furthermore, the magnetic pole near earth's geographic north pole is actually the south magnetic pole. When it comes to magnets, opposites attract. This fact means that the north end of a magnet in a compass is attracted to the south magnetic pole, which lies close to the geographic north pole.

Magnetic field lines outside of a permanent magnet always run from the north magnetic pole to the south magnetic pole. Therefore, the magnetic field lines of the earth run from the southern geographic hemisphere towards the northern geographic hemisphere.

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2021-06-17 07:08:31 Why Do Athletes Have a Lower Heart Rate?

Increased cardiovascular fitness causes real physical changes in the structure of the heart. The muscles in the heart wall thicken, and the heart pumps more blood with each beat. That increased efficiency means an athlete's resting heart rate falls to a level that could indicate trouble in a nonathlete. Many athletes don't realize that high levels of conditioning also cause heart symptoms that doctors might mistake for serious problems. During exercise, the untrained heart beats faster, but not as efficiently as in trained athletes. Output during maximum exertion increases to 14 to 20 liters per minute, far below the 40 liters per minute of an elite athlete.

The resting heartbeat of an athlete can fall below 40 beats per minute. When you exercise, your heart works harder when other muscles in the body pump more blood back to the heart. The major muscles of the legs have large veins that fill during the relaxation stage of the movement, and the muscle contraction in the active movement pushes the blood back into the circulatory system. Increasing blood flow triggers a faster heartbeat. Because the heart muscle of conditioned athletes enlarges and strengthens, the hearts of athletes pump more blood per beat. An athlete's maximum heart rate, as well as resting heart rate, falls below the pace of the average heartbeat.

Conditioning causes physical and electrical changes in the heart, creating a beneficial condition called "athlete's heart." Aerobic training, such as running or swimming, causes your heart to develop larger heart chambers. Participants in anaerobic sports, such as weightlifting, increase the thickness and strength of their heart muscles. Mixing the two types of training creates both types of heart improvement. During intense exercise, the hearts of highly trained athletes pump as much as twice the volume of blood as the hearts of untrained people.

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