Pregnant women like eating raw mangoes and tamarind. .

Craving for unusual food is considered as the first sign of pregnancy. In reality, although some women do get strong cravings, many do not. No one knows for sure what causes food cravings. Many women find that their senses of taste and smell are changed by pregnancy. For example, some women experience an odd metallic taste in their mouths very early in pregnancy (may be the first sign of pregnancy for an ‘experienced’ mother); others find that taste and smell are dulled. It is possible that these changes affect food likes and dislikes. Some people think that cravings happen in response to temporary deficiency of specific nutrients.

There is probably some truth in this, but it is not the whole story. We only need minute quantities of each vitamin and mineral-certainly not enough to justify a continual craving for just one food. for some women, food cravings may be a conscious or subconscious response to emotion. They may crave a favourite childhood food, or a food that is of special significance to their religion or culture. Cravings for unusual food may also be a private way of marking the special state of being pregnant. Rather than develop a food craving, many women find they suddenly go off certain foods or drinks like fried foods and coffee.

This is often related to pregnancy sickness, but may also be the body’s way of ensuring that they eat and drink wisely. Generally, there’s no harm in giving into food cravings, especially if doing so helps getting through phases like early morning sickness which can be pretty distressing. However this must be done in moderation. Eating a lot of one food only means eating less of other foods and therefore running the risk of becoming deficient in important nutrient. A craving for non-food item-such as ash or soap or toothpaste-is known as ‘pica’. Pica is potentially very harmful if indulged in and must be resisted. Also, substances like soaps and ash may prevent the absorption of nutrients and other food substances.

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Human papilloma virus

The viruses that contain DNA as their genetic material and can induce tumors are called DNA-tumor viruses. They are placed under Papova virus group. Papilloma virus is one type of Papova virus. They cause papillomas or warts of cutaneous and mucosal epithellia in human and other animals, therefore they are called Papilloma viruses. They are nearly 60 sub-types in the warts caused due to human papilloma virus. Transmission is by contact with virus either in living skin or in fragments of shed skin. Genital warts frequently spread by intercourse and perianal warts may reflect homosexual activity. There appears to be a close, if not causative, relationship with genital warts, especially due to HPV type 16 and 18 and carcinoma of the cervix. Nearly 80 per cent of cases with cervical carcinoma harbour one of these viruses. Cervical carcinoma is most common among women with several sexual partners. It is suspected that penile cancer is also due to these types of papilloma viruses.

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Can Mosquito carry the AIDS causing virus?

Acquired Immune Deficiency Syndrome (AIDS) is caused by Human Immunodeficiency Virus (HIV). The Presence of HIV in blood, semen and vaginal secretion of infected people promotes the spread of the infection through sexual contact, exposure to contaminated blood and blood products. The virus can also be transmitted to the child from the mother. There is no concrete evidence to show that it is transmitted through insect bites.

However HIV does not replicate in mosquitoes. Scientists at centre for Disease control, Atlanta have proved that even in mosquitoes injected with HIV contaminated blood, the virus survives only for one hour. Further, studies on epidemiology of AIDS have provided no evidence linking mosquitoes with disease.Mosquitoes do transmit diseases like Malaria. In the case of AIDS they act as biological vectors and a certain period of time has to elapse for the parasite to become infective. The vector can transmit the infection only after the infectious agent undergoes a developmental process or multiplies in its body.

Is sucking a cut finger, good?

Saliva which is secreted in the oral activity contains many substances which have antibacterial and antiviral activity. These include immune globulins such as IG-A, G, M which help clump the bacteria. Also there are lysozymes which destroy the bacterial cell wall. A protein lactoferrin found in the saliva also help in inhibiting multiplication of bacteria by interfering with iron utilization by the germs. The physical effect of sucking out the infecting material implanted during the cut also plays an important role. Forcibly bleeding the finger and flushing it with running water is equally effective in prevention of bacterial contamination. Even though the biochemical contents of saliva are good, the microbiological contents are not. The oral cavity has been recognized as an area of dangerous microbial contamination and exposing the skin with a cut to such an environment might be inviting trouble.

Why Black Stripe is bordering a color TV screen?

The black bordering is the envelope of the picture tube. The picture tube has to withstand the high atmospheric air pressure, because the glass envelope is evacuated. In older TVs, a special glass or plastic shields were placed before the picture tube to protect any glass from hitting the viewer in case of an implosion. But modern TVs incorporate implosion protection without any shield. In one arrangement a metal rim band called kimcode is held around the tube by a tension strap. The black bordering is nothing but this metal band for implosion protection, which prevents the glass from spilling over if the implosion happens.

How Rainbow colors have seen on CD?

Display of colors by a CD can be understood in terms of the working of a plane optical reflection grating. It is a flat optical device whose surface is ruled/striped with a set of closely and uniformly spaced lines, such that light is reflected by the gaps and absorbed by the lines. When light falls on a plane reflection grating, it is scattered in all directions by each of its reflecting stripes.

These waves from individual gaps are termed wavelets. When we look at the grating from a distance, wavelets from different stripes travel different distances to reach the retina of our eye. Their crests do not reach a given point at the same time. Usually crests of some wavelets and troughs of others reach a point. troughs have the property of partially or totally nullifying crest and vice versa, depending on their strengths. In this case the wavelets are said to interfere destructively.

But for certain orientations of the grating, it so happens that troughs of all wavelets reach a point together, enhancing the effect of each other. The wavelets are then said to interfere constructively. Ordinarily, when light falls on a grating, wavelets corresponding to all wavelengths are sent out by the reflecting gaps. Since the conditions of constructive interference hold good only for some particular wavelength, light intensity at the receiving point is exceptionally high only for that wavelength. Light from the grating from the related direction is thus rich in the corresponding color. Similarly light from slightly different direction is rich in another color. A CD has a data recording track, which spirals from its outer periphery to the inner circular boundary. This takes many tens of thousand rounds about the CD's center.

When examined along a radius of the CD, it is found to have a structure similar to that of a reflection grating- a set of almost straight tracks running perpendicular to the radius and separated by gaps. Therefore, like a grating the CD also displays colors.

Euro norms

Euro norm are meant for regulating vehicular emissions in Europe. The norms are expressed in terms of the weight of pollutants such as carbon monoxide (CO), hydrocarbon, oxides of nitrogen (NOx) and particulate matter emitted per kilometer of vehicular run with load. These ceilings have been fixed for various categories of vehicles. For instance, there are emission levels for petrol-driven and diesel-driven vehicles based on the capacity of the engines. The pollution measurements under engine idling conditions without application of load on the vehicles does not reflect the exact quantum of various pollution emitted by the engines in reality.

In any internal combustion engines, as the speed or acceleration is increased, the time allowed for combustion of the fuel is varied than the idling condition. This variation is different in a carburetor engine and in a fuel injection petrol or diesel engine. In a carburetor engine, the CO will be maximum at idling speed. In a diesel engine, the smoke will be maximum upon sudden acceleration. The Euro norms adopt certain specified driving cycles related with time Vs speed. During these cycles of operation of the engine, the mass of each exhaust gas component is evaluated. The mass is exhaust gas volume. Exhaust gas is generated when the vehicle is operated on a chassis dynamometer according to certain standard driving cycles which stimulate driving conditions in urban traffic.

Why warm up is need before playing physically?

Warming of body raises temperature from 1 to 2◦F, in order to reduce the viscosity of muscle to have better mobility, range of motion, stretch reflexes for better power in muscle and cardiorespiratory adjustment of supply of blood, oxygen and glucose as per demands of effort during playing. The warm-up exercises include rolling, stretching, flexing and agilitic movements to develop coordinated complex movements of neuromuscular function (mechanism of reciprocal stimulation and inhibition). This thereby, prevents incidence of injury of musculo-skeletal structures, improve efficiency of muscular effort (ergonomics). Lack of adequate warming up before playing develops bodily and psychological problems.