Why do lips become dry during winter?
Why do lips become dry during winter? Our skin is endowed with both cold and warmth receptors. There are more cold receptors than warmth receptors. Therefore peripheral detection of temperature mainly concerns detecting cool and cold instead of warm temperatures. When the skin is chilled over the entire body immediate reflex effects are involved to increase the temperature of the body. The two important effects are providing a strong stimulus to cause shivering, with resultant increase in the rate of body heat production and promoting skin vasoconstriction to diminish the transfer of body heat to the skin. The effects of hypothermia depend on whether there is whole body exposure or exposure of only body parts. When the whole body is exposed, metabolic processes; particularly in the brain and medullary centres slow down, causing death, before apparent changes in the cells or local reactions will occur in the parts of the body. When only parts of the body gets exposed to very chill temperature, the local reactions begin to appear. These reactions are chilling and freezing of cells and tissues leading to frost bite. The injury is in two ways. (1) Crystallisation of the intra and extra-cellular water causing physical dislocation within the cells, which is the direct effect. (2) The indirect effects are exerted by circulatory changes. Depending on the rate at which the temperature drops and the duration of the temperature, slowly developing chilling may induce vasoconstriction and increased permeability, leading to oedematous changes. This results in the dryness of the body skin and also lips. When the drop in temperature persists for a long time atrophy and fibrosis may follow, which result in permanent circulatory impairment as well as tissue damage. Often gangrene follows thawing and the frostbitten areas are lost. This we often experience in the lips by the appearance of infarction necrosis of affected areas even after the temperature begins to return towards normal.
Does the change in mother's food affect the baby?
Whatever the nursing mother eat will be secreted in her milk, but in insignificant quantities. Generally if the mother tolerates a particular food item well the baby also tolerates it well.
A normal well nourished mother secretes about 500 ml of milk daily for the first 6 months to one year and after that the quantity slowly comes down. Whereas an undernourished mother's milk is insufficient in fats and vitamins and inadequate for the baby also.
Eating fishes and vegetables contaminated with pesticides may cause problems in the baby because of their secretion in the milk. Eating spices, condiments, chocolates, onions, tomotoes may cause loose stolls in the babies.But the problems are plenty in the baby of a mother who smokes, drink alcohol and abuses the drugs. Almost all the drugs are excreted in the breastmilk and they will have their effect on the body.
For medical reasons if the mother has to take certain drugs like anticoagulants, anti-cancer drugs, antithyroid drugs, radioactive drugs, purgative etc., seh has to stop feeding her baby as long as she is on those rugs.
Why does my cell phone make screechy noises when I place it near my computer?
This sounds like a case of electromagnetic interference (or EMI), which is what happens when radio waves emitted by one device cause undesirable behavior in another.Virtually every piece of electrically powered equipment acts as a radio transmitter, whether it is supposed to or not. That's because the rapidly changing electric currents running through these devices naturally radiate electromagnetic waves. This is an inevitable by-product of using electricity to do useful things, and it is analogous to the clanking and clattering sounds that mechanical devices make as they work. Computers are particularly "noisy" because they rely on rapidly changing currents to act as clock signals that coordinate their calculations.Just as changing electric currents radiate radio waves, radio waves induce electric currents in conducting materials. This is how radio receivers detect the signals transmitted by radio stations. The same effect is used to heat pots and pans on inductive cooktops. Inductive coupling can also have undesirable consequences, however.One explanation for the phenomenon you describe is that your computer unintentionally emits radio waves in the range of frequencies reserved for cell phone communications, typically around 800 megahertz (MHz). If the signal coming from your computer is strong enough, your phone could mistake it for a cell phone transmission. Computer noise, however, does not contain the sort of information that your phone's onboard computer is programmed to expect. Thus, it responds to the resulting cascade of communications failures by creating a series of audible alerts.Another explanation involves a deeper connection between your two devices. In addition to its other components, a cell phone has an audio amplifier that drives its speaker, and the radio waves emitted by the computer may induce currents in the wiring of the amplifier itself. The resulting audio output then would reflect what your computer is doing at that moment but would sound to a person like random squeaks and squawks.There is no way to stop electrical devices from generating radio waves. The only way to prevent EMI is to keep spurious radio waves under wraps. Most electronic devices are housed in cases designed to trap these electromagnetic waves; they are made of metal or have a coating that conducts. Holes in the cases and thin spots in the coating allow some radio waves to leak out. Usually the leakage is too small to have any effect except right near the source, where it is most intense. And that is why your cell phone only acts up when it is right next to your computer
Do animals also have blood groups like humans?
In man blood group is applied to single factor.
This factor is agglutinogen and is also called antigen. It is found on the surface of red blood corpuscles. Accordingly a person with `A' antigen is designated as a person with A-group, with `B' antigen as B-group, with both A and B antigens as AB-blood group and a person without any antigens is designated as O-blood group. In the case of animals blood group is applied to combinations of blood factors. So it is preferable to call it as blood group systems rather then blood groups. Each system has many factors, which are together called blood group factors. Dr. J. Moustgaard, of the Royal Veterinary & Agricultural College, Copenhagen has identified in cattle ten group systems namely A,B,C,FV,J,L,M,SU, Z and R'S'. Except J and L, all the other group systems have more than one group factor. For example the group factors of the group system A are designated as A{-1}, A{-2}, D, H, Z'. The grouping factors are particular serum proteins. Acquiring of each protein is an inherited character. So examination of blood sample from within a breed might eventually prove a very useful means of selection. It might also indicate what mating could be expected to result in infertility. The B-group system only has greater number of grouping factors. It has nearly 27 group factors, which are called phenogroups. Some of these are unique to particular breeds. They are particularly valuable in determining incorrectly stated parentage. In dogs serum major groups have been recognised in the USA and they are referred to as A to G. In veterinary practice blood transfusion is used in cases of haemorrhage and shock and to a lesser extent as part of the treatment of certain infectious diseases. In cattle the donor and recipient are usually in the same herd. This fact lessens the risk of introducing infection and incompatibility does not arise. But normal antibodies against the blood group factor-J are sometimes found in cattle. Thus if the donor's blood is J-positive and the recipient's blood contains normal antibody called anti-J the so-called transfusion reaction might be expected immediately following blood transfusion. These reactions are dyspnoea, muscular twisting, increased salivation and circulatory disturbances. However, if an animal has been exposed to repeated blood transfusions, a different situation will arise. The animal will now have formed antibodies against the blood group antigens it does not have itself. It is therefore by no means unlikely that the blood of donor and the recipient are incompatible. If this is so, transfusion will set off strong transfusion reactions. Such reaction can occur on the second or on subsequent blood transfusion.
Why does rain come in drops and not in a continuous stream?
When warm wet air rises, it cools and water vapour condenses to form clouds. A cloud is made of small drops of water or ice crystals, depending on its height and how cold its surrounding air is. Most rain originates in nimbus or in towering cumulonimbus clouds. To form rain, water vapour needs what's called a condensation nucleus, which can be tiny particles of dust, or pollen, swept up high into the atmosphere. When the condensing droplets that form the cloud get large and heavy enough to overcome the upward pressure of convection, they begin to fall. Although all clouds contain water, some produce precipitation and others drift away placidly without giving rain. First all the droplets in a cloud are less than 20 micrometer in diameter. In a cloud there are lot hygroscopic particles and normally drops form by absorbing moisture by these particles. Rain is restricted to drops of water that fall from a cloud. They have a typically diameter of at least 0.5 mm. A raindrop large enough to reach the ground without evaporating contains roughly a million times the water of a cloud droplet (typical diameter is 0.012 mm). No matter what the intensity of rain is the size of the drop rarely exceeds about 5 mm. Larger drops do not survive as the process of surface tension which holds the drop together is exceeded by the frictional drag of air and therefore larger drops break apart into smaller ones. Raindrops as they descend, initiate a chain reaction, a downward trend of the water droplets, with the larger drops always breaking — a common feature observed when one forcefully disgorge the contents of a glass of water. Most rainfall begins as snow crystals or other solid forms. Entering the warmer air below the cloud, these ice particles often melt and reach the ground as raindrops. A raindrop starts falling and then picks up speed due to gravity. When one drop starts falling a wake follows in the cloud. (Wake is a clearance that is normally found behind a speeding boat.) This clearance is convenient for another drop to follow and not exactly in the same path but close to it, says Mr. C. Ranganathan of Tiruchy. Drops that pick up speed are slowed down by the drag of the surrounding air. Indeed the smallest drop may not fall at all, being suspended or perhaps forced upward by ascending currents of air until they grow large enough to fall. As larger droplets descent, they produce an airstream around them. The larger the cloud droplet the better the chance of its colliding with a giant droplet. So each drop falls at a different speed as their sizes are different. There are collisions between raindrops. Some collisions cause drops to coalesce, forming a large drop and some cause drops to break into smaller ones. As the number of drops grows the intensity of rain increases. Collision does not guarantee coalescence. Experiments have indicated that the presence of atmospheric electricity may be the key to what keeps the drops together as they collide. That is when a droplet with a negative charge collides with another with a positive charge their electrical attraction may hold them together. Rate at which drops fall is size dependent. Giant droplets fall rapidly. Thus drops keep on falling side by side and not in a continuous stream.
What is the difference between tv screen and computer monitor?
ANSWER I: Computer monitors are capable of accepting signals only from the central processing unit of a computer. Therefore they are unable to reproduce a colour image from a composite video signal whose waveform conforms to a broadcast standard (NTSC, PAL, D-MAC, etc.).Computer monitors are fitted with connectors characteristic of data processing systems (eg. DINorDB9/15 also called MINI SUB D15Connectors) and do not have an audio circuit.They are controlled by special adaptors (eg. monochrome or graphic adaptors), which are integrated in the central processing unit of the automatic data processing machine. . Their display pitch size starts at 0.41 mm for medium resolution and gets smaller as resolution increases.Sor to accommodate the presentation of small, yet well-defined images, computer monitors utilise smaller dot (pixel) sizes and greater convergence standards than those applicable to television receivers. In computer monitors, the video frequency (bandwidth), which is the measurement determining how many dots can be transmitted per second to form an image, is generally 15 MHz or greater. But in case of TV or video monitors, the bandwidth is generally not more than 6 MHz.The horizontal scanning frequency of these monitors varies according to the standards for various display modes, generally from 15 kHz to over 155 kHz. Some are capable of multiple horizontal scanning frequencies. Horizontal scanning frequency of video/TV monitors is fixed, usually 15.6 or 15.7 kHz depending on applicable television standard.
ANSWER II: In all computer monitors, the image is painted on the screen by an electron beam that scans from one side of the display to the other. In television, transitions in colour, intensity, and pattern as the beam scans across the screen tend to be gradual.But, the transitions a computer monitor typically processes are abrupt as areas of high intensity transform to areas of black as text is placed on the screen. Television uses a process that relies on the brain's ability to integrate gradual transitions in pattern that the eye sees as the image is painted on the screen. During the first phase of screen drawing, even-numbered lines are drawn. In the next, odd lines are drawn. The eye integrates the two images to create a single image. The scan is interlaced. But, a computer viewer has different needs. The viewer is sitting within a foot or two of the screen and viewing a frequently changing text image.If a computer monitor used the same method of display as TV, many transitions would produce an annoying amount of flicker, because the brain is less able to integrate the dramatic transition from bright to dark.Also, a secondary problem occurs due to inability of the monitor to paint interlaced images exactly in between the lines from preceding scan.Text images makes this much more visible to the eye at the close range, and at the relatively slower speeds of an interlaced scan. So, computer monitors use a technique that paints one continuous image at a time and is said to be non-interlaced.Consequently, although the scan frequencies of the TV receiver and monitor are similar, computer monitors must be designed to paint every line during every write of the picture to prevent flicker. This requires electronics that operate twice the speed as that of a television.
Why is fire hot?
Chemical reactions can be either exothermic(heat liberation) or endothermic (heat absorption). Oxidation reactions are exothermic and reduction reactions are endothermic. Combustion is an oxidation reaction and hence is exothermic. All liquid,solid and gaseous fuels contain any one of the three combustibles constituents viz, carbon, hydrogen ans sulphur. When a fuel is burnt the heat liberated makes the products of combustion hot. The products of combustion are carbon dioxide, water vapour ans sulphur dioxide. Along with these, the unused oxygen in the atmospheric air supplied for combustion and also the entire quantity of nitrogen which is the major constituent in the air are also heated. That is why fire is hot.
Since clouds contain tiny water droplets, why are rainbows not permanently present?
On a rainy day, sunrays, which are polychromatic(with all the seven colours), fall on water droplets at a certain incident angle adn refract with certain other refractive angle because water is denser than air. Since the line of incidence of the rays may not be collinear to the drop's diameter, the angle of refraction, however, is different for different colours of the rays in order that each colour catches up with the other at the opposite side of the droplet (remember the frequency of a given colour is invariable irrespective of the medium and the velocity of all colours is same in a given medium). In other words, a polychromatic ray gets dispersed into seven colours of the visible light as the light beam is refracted into the body of the droplet. The colours, thus dispersed undergo total internal reflection on the opposite inner side of the droplet and reach the eye to enable us feel the virtual image of the rainbow.(In fact, the mechanism of appearance of the rainbow is more complex than this and there is a cooperative phenomenon that includes interference in space and time.) However the extent of the resolution of the seven colours in the droplet depends greatly in the extent of the (path) length the rays cover in the droplet. Consider the case of weven sprinters of varied sppeds covering s ahorter (say 100 mts) and a longer track (say 400 mts). In a shorter track the ralative gap, after the run is less whereas ina longer track it is more. In normal clouds, the droplets are too small to cause sufficient resolution of the colours and to enable total internal reflection and hence rainbow is invisible with dry clouds. On a rainy day, the droplets are big enough to cause the resolution and total internal reflection of the clours to enable us to see the rainbow(also theyare numerous and closer ans t an appropriate viewing angle to allow the cooperative phenomenon.)
Soaps come in different colours. But why is soap's lather always white in colour?
Lather or foam is nothing but a large collection of small soap bubbles. A soap bubble is , in turn, a very thin film of soap solution enclosing some air. Because of the low surface tension of soap solution, the film can stretch and spread and form innumerable bubbles with a very large total surface area. Due to this, whatever slight tint is present in the thin film of the coloured soap solution gets subdued. Although a soap film is more or less transparent, the lather or foam looks white because the light striking this large collection of bubbles gets scattered. That is the reason why all kinds of lather or foam appear white.
How does lightning affect TVs?
Lightning is actually a sudden discharge of high voltage and high current arisiing out of large viltage(potential) differences between charged clouds. These surges, in their path towards the earth, can strike power lines and antennae and pass through the wires to the terminal equipment such as TV.. The huge currents and voltages, even though of short life, can damage the electrical components and electronic circuits which are usually designed for low power. The surges are so powerful that they can destroy the equipment even if they are off but connected to the mains/antenna.
Why do eggs become hard on boiling?
Egg contain 67 per cent proteins (in egg white) and 33 per cent fats and proteins (in egg yolk). Egg white protein is mostly albumin (ovalbumin and Conalbumin) All proteins have primary,secondary and tertiary structures.Tertiary structure of egg white protein is due to hydrophobic interactions and hydrogen bonding. They also contain Cysteine amino acid, which has sulfhydryl group (SH).These sulfhydryl groups form covalent disulfide bonds and hold 2 distant sections of proteins in close proximity. Disruption of the tertiary structure (or 3 dimensional structure) due to heat, chemicals or acidity is called "denaturation".When we heat an egg, the, heat breaks the intermolecular forces and the tertiary structure gets broken. The proteins unfold from their nature folded structure and precipitate forming a white solid mass
Why are fishes not able to survive in distilled water?
Take a fresh grape fruit and keep it in distilled water for an hour. it is stouter than before. Another fresh grape fruit kept in salty water for an hour will appear slim and wrinkled. The grape has dissolved minerals,sugars and other ingredients in its juice. The skin of the grape is a semi permeable membrane across which water can diffuse from one side to the other through osmosis. When the grape is kept inside distilled water, the concentration(salinity) of juice in the grape is higher than that of water and water moves osmotically from outside the grape to inside. Hence the grape appeared stouter. the reverse happened in the case of salty water. The skin of the fish is like the skin of the grape fruit. If the fish is in distilled water, there is an osmotic flow of water from outside the fish to the inside because the salinity of the fish body is higher than that of water. Thus there is danger of dilution of the body fluids of the fish or at worst that of being blown out if the fish is to be in distilled water for a very long period of time
How does remote control in TV work?
In earlier days, remote controls wre based on ultrasonics (sound frequency above the audible range of frequencies). The controlling circuitry included a hand held transmitter 9that transmits ultrasound) and a TV-based receiver circuit. Electronic filter and stepper motors were used to allow/select certain frequencies and perform various functions depending on the key pressed. But the recent remote controls use infra-red(IR) rays and a special binary (0 and 1) coding mechanism. The code, intensity and wavelength of the IR wave, help to select different functions. Depending on the key pressed, a signal is sent out by IR source say, an injetion laser diode(ILD). It generates a code in parallel format. This is converted to a series format by s shift register. This signal is received by photo-sensitive devices such as an avalanche photo diode at the receiver. Here another shift register is used to convert the code back to a parallel form. This operates a one-of-n decoder, which selects one function from a set of "n" predefined functions and executes it
What makes the earth rotate?
The earth rotates simply because it has not yet stopped moving. The Solar System, and indeed the Galaxy, were formed by the condensation of a rotating mass of gas. Conservation of angular momentum meant that any bodies formed from the gas would themselves be rotating. As frictional and other forces in space are very small, rotating bodies, including the Earth, slow only very gradually.
