eBook Chapters

Water is the only substance that exists in the atmosphere in all the three phases, i.e., solid, liquid and gas. The moisture on the earth’s surface is in a constant phase change. The moisture content of the atmosphere is about 0.035% of all fresh water. The atmosphere receives its supply of moisture from the earth’s surface through evaporation from oceans, lakes, rivers, damp soil, etc. and through transpiration from vegetation. Water vapour is the gaseous state of water and is invisible.

The amount of water vapour present in the atmosphere is called atmospheric moisture or humidity. It is a measure of the amount of water vapour dissolved in the air, not including any liquid water or ice falling through the air. While humidity itself is a climate variable, it also interacts strongly with other climate variables. The humidity is affected by winds and by rainfall. Moisture content is determined by the local rate of evaporation, air temperature and the horizontal transport of moisture. Humidity indicates the likelihood of precipitation, dew or fog. It also plays a major role in the heat budget and the weather phenomenon of the atmosphere.

Water is the only substance that exists in the atmosphere in all the three phases, i.e., solid, liquid and gas. The moisture on the earth's surface is in a constant phase change. The moisture content of the atmosphere is about 0.035% of all fresh water. The atmosphere receives its supply of moisture from the earth's surface through evaporation from oceans, lakes, rivers, damp soil, etc. and through transpiration from vegetation. Water vapour is the gaseous state of water and is invisible. The amount of water vapour present in the atmosphere is called atmospheric moisture or humidity. It is a measure of the amount of water vapour dissolved in the air, not including any liquid water or ice falling through the air.

Water vapour is constantly being cycled between the atmosphere and the earth's surface. The input rate (the rate at which water vapour enters the atmosphere from the ground through evaporation) and output rate (the rate at which water moves from the atmosphere to ground through precipitation) are equal. The average length of time that individual molecules of water remain in the atmosphere is called the residence time. It can be found by dividing the mass of the substance in the atmosphere (in kilograms) by the rate (in kg per year) at which the substance enters to and exists in the atmosphere. The total volume of atmospheric water vapour at any instance over the globe is about 14000 km³, which is 0.001% of the hydrosphere.

Although water vapour is lighter than air, the combination of higher temperatures and the ocean source tends to restrict it to the lower atmosphere. The decrease of water vapour with elevation is quite important in many meteorological processes. Infact, most of the water vapour is contained within the lower 5 km of the atmosphere (> 90%) and more than half is actually contained within the lowest 1.5 to 2 km. Less than 5 - 6% of the water is above 5 km, and less than 1% is in the stratosphere.

Water is the only substance that exists in the atmosphere in all the three phases, i.e., solid, liquid and gas. The moisture on the earth’s surface is in a constant phase change. The moisture content of the atmosphere is about 0.035% of all fresh water. The atmosphere receives its supply of moisture from the earth’s surface through evaporation from oceans, lakes, rivers, damp soil, etc. and through transpiration from vegetation. Water vapour is the gaseous state of water and is invisible.

The amount of water vapour present in the atmosphere is called atmospheric moisture or humidity. It is a measure of the amount of water vapour dissolved in the air, not including any liquid water or ice falling through the air. While humidity itself is a climate variable, it also interacts strongly with other climate variables. The humidity is affected by winds and by rainfall. Moisture content is determined by the local rate of evaporation, air temperature and the horizontal transport of moisture. Humidity indicates the likelihood of precipitation, dew or fog. It also plays a major role in the heat budget and the weather phenomenon of the atmosphere.

A big layer of air called the atmosphere surrounds the earth. The air within this layer moves from place to place when it warms up or cools down. This moving air is known as wind. In other words, air in motion is called wind. Winds move moisture and heat around the world and also produce much of our weather.

The strength of the wind can vary enormously. Sometimes air moves slowly and the wind is barely noticeable. When the weather is clear there may be a gentle breeze. When the wind is still very light, but it can be felt and there may be rustlings by leaves. At other times, the air can move very quickly and become a gale or hurricane, blowing down trees and damaging electric poles and buildings.

Winds are part of a global air circulation system that acts to balance temperature and pressure around the world. Different parts of the world receive different amounts of heat from the sun. This differential heating in turn results in differences in temperature and air pressure around the world, which drives the world’s winds.

As equatorial areas are heated most, the air above them warms and rises as it becomes lighter than the surrounding air, causing an area of low pressure. In cooler areas, the air sinks because it is heavier and results in an area of high pressure. Winds will blow as air is squashed out by the sinking cold air and drawn in under the rising warm air. Any difference in temperature like this will always cause a difference in air pressure, and therefore winds will blow. These movements result in a global wind pattern, with air moving between different areas around the world and also at different heights in the atmosphere. Colder air from the poles tends to sink and move towards the equator closer to the surface of the earth. In contrast, warm air from the equator rises and moves towards the poles high in the atmosphere because it is lighter.

Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of earth. The gas molecules of the atmosphere are pulled towards the earth by the force of gravity and hence exert a force on earth surface. Atmospheric pressure can be calculated as the summed weight of all gas molecules between a horizontal plane and top of the atmosphere and divided by the area of the plane. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location.

The atmospheric pressure is weight of the air which lies vertically above an unit area centered at a point. Normal pressure of air is 1.034/cm².

Pressure is defined as the force per unit area.
At the surface of the earth the atmosphere air exerts a pressure of about 10⁵ Newtons/m² or 10⁵ Pascals, which is called one bar or one atmosphere. Evangelista Torricelli (1608-1647) devised a method for measuring the atmospheric pressure by mercury (Hg) barameter in 1643.

Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of earth. The gas molecules of the atmosphere are pulled towards the earth by the force of gravity and hence exert a force on earth surface. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Atmospheric pressure influences other weather elements in a significant way. Small changes in air pressure may not be felt, but they are important for bringing a change in weather. Atmospheric pressure can be calculated as the summed weight of all gas molecules between a horizontal plane and top of the atmosphere and divided by the area of the plane. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location.

Measurement of atmospheric pressure

The standard unit of pressure in the SI system is the Pascal which is the name given to one Newton per square metre (N/m²). For meteorological purposes, standard sea-level pressure is 101325 pascal (Pa). To simplify this large number, the millibar unit (mb) has been adopted, which is equal to 100 pascals. Units like kiloPascal (kPa) or hectoPascal (hPa) are also used to measure pressure. 1 kiloPascal is equal to 10 millibars and 1 hPa is 1 millibar. The standard sea-level pressure is represented as 1013.2 mb or hPa.

Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of earth. The gas molecules of the atmosphere are pulled towards the earth by the force of gravity and hence exert a force on earth surface. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Atmospheric pressure inf luences other weather elements in a significant way. Small changes in air pressure may not be felt, but they are important for bringing a change in weather. Atmospheric pressure can be calculated as the summed weight of all gas molecules between a horizontal plane and top of the atmosphere and divided by the area of the plane. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location.

FACTORS AFFECTING ATMOSPHERIC PRESSURE

Air pressure never remains constant. Air pressure is greatly influenced by air temperature, altitude, water vapour presence in the air, rotation of earth, etc. However, these factors are not independent of each other in affecting the atmospheric pressure.

Temperature: Hot air expands and exerts low pressure. Cold air contracts and exerts high pressure. Thus, increase in temperature decreases the air pressure. Places nearer to equator experience low pressure due to prevalence of high temperature. The air being cold and heavy throughout the year a high pressure belt is created in both polar regions.

Altitude: Pressure varies smoothly from the earth’s surface to the top of the mesosphere. The pressure depends on the density or mass of the air. The density of air depends on its temperature. The density of air decreases with increase in height so the pressure also decreases with increase in height. At low altitudes above the sea level, the pressure decreases by about 1.2 kPa for every 100 metres.

Water vapour: Water vapour content of air is low in cold areas than that in dry areas. Hence, moist air of high temperature in dry areas exerts less pressure compared to cold air.

The mass of a body is usually defined as the material content of the body whereas the weight of the body is defined as the force with which the body is attracted towards the earth due to gravity. Therefore, the weight of a body is the product of its mass and acceleration due to gravity. The air in the atmosphere, which is a mixture of several gases has certain mass and although not very dense, will acquire some weight due to gravitational force of attraction when the entire column of the atmosphere from the ground level to the top of it is considered. Pressure is defined as the force for unit area. Therefore, the atmospheric pressure is defined as the force exerted by an air column of units area of cross section extending from earth’s surface to the top of atmosphere. As we go up in the atmosphere the height of the air column decreases, the air also become rarer and the atmospheric pressure decreases with increase in height.

Temperature is the physical property of an object that quantitatively expresses the hotness or coldness. Most of the weather parameters are dependent on temperature, directly or indirectly. It has important role to play in the development and growth of all living organisms in all stages of their growth. Atmosphere receives the heat energy from the sun and its temperature increases. Due to different amount of heat energy receipt at different places, the air temperatures at different places also vary. The variation in air temperature basically results into air motion, so as to equalize the energy content of the different regions of the earth. Thus, atmospheric temperature is one of the basic elements of weather and climate.

The temperature at a given location and time is affected by energy transfer processes including conduction, convection, advection and radiation. The controls of temperature include those factors that bring about spatial variations in temperature. The important factors that determine the temperature of a particular place on the earth’s surface are latitude, altitude, distribution of land and water, topography, ocean currents, prevailing wind, cloudiness, precipitation, nature of the surface, and turbulence.

Temperature is the physical property of an object that quantitatively expresses the hotness or coldness. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot. When a heat transfer path between them is open, heat spontaneously flows from bodies of a higher temperature to bodies of lower temperature. If no net heat flow occurs between two objects, the objects have the same temperature which are then said to be in ‘thermal equilibrium’. Temperature plays an important role in all fields of natural and applied sciences. Most of the weather parameters are dependent on it, directly or indirectly. It has important role to play in the development and growth of all living organisms in all stages of their growth.

Atmosphere receives the heat energy from the sun and its temperature increases. Due to different amount of heat energy receipt at different places, the air temperatures at different places also vary. The variation in air temperature basically results into air motion, so as to equalise the energy content of the different regions of the earth. Thus, atmospheric temperature is one of the basic elements of weather and climate.

Temperature is the physical property of an object that quantitatively expresses the hotness or coldness. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot. When a heat transfer path between them is open, heat spontaneously flows from bodies of a higher temperature to bodies of lower temperature. If no net heat flow occurs between two objects, the objects have the same temperature which are then said to be in ‘thermal equilibrium’. Temperature plays an important role in all fields of natural and applied sciences. Most of the weather parameters are dependent on it, directly or indirectly. It has important role to play in the development and growth of all living organisms in all stages of their growth.

Atmosphere receives the heat energy from the sun and its temperature increases. Due to different amount of heat energy receipt at different places, the air temperatures at different places also vary. The variation in air temperature basically results into air motion, so as to equalise the energy content of the different regions of the earth. Thus, atmospheric temperature is one of the basic elements of weather and climate.

The potential of atomic absorption spectrometry/spectrophotometry/ spectroscopy for determination of metallic elements was first realized by Alan Walsh during 1950. The standard equipment termed as atomic absorption spectrometer/ spectrophotometer (AAS) has now gained a reputation in the field of analytical chemistry for determination of very small concentrations of metallic elements and metalloids. As little as 0.01 ppm of many elements can be determined through this tool. Recently, the Zeeman background correction technique has further enhanced the quality of the results obtained from the flame-less graphite furnace atomizer. Combining the very latest in AA technology with the most powerful computing and software available many manufacturers have developed several designs/models of AAS based on flame or flame-less technique.

Introduction

The first application of atomic absorption spectra to chemical analysis was made just over 100 years ago by Kirchoff (1860), who demonstrated the presence of various elements in the solar atmosphere. He and Bunsen, demonstrated shortly afterwards that atomic spectra, whether in emission or absorpiton, could be the basis of a powerful method of chemical analysis. Walsh (1955) recognized the potential advantages of the absorption method over emission method and devised simple and versatile apparatus applicable to the routine analysis of solutions of a wide range of elements. Alkemade and Milatz (1955) published papers describing the application of atomic absorption  techniques to chemical analysis.

Introduction

Biological systems are complex and are full of mysteries. Understanding function in relation to structure is crucial in many biological systems. A microscope is used to magnify, resolve and visualize a substance that is impossible to see by naked eyes and plays a vital role in various biological studies. We can visualize macroscopic organisms like animals, plants, and insects by the unaided eye but not bacteria, viruses or individual proteins. Biological structures have sizes variable over such a wide range that is not possible for a single microscopic technique to analyze all of them. Therefore, different types of microscopes with varying magnification and resolving abilities were developed to unveil the structural complexities of biomolecules (Fig. 1). Over the last 100 years, several types of microscopes have been designed and used in various fields. The microscopes work on different principles, and have a broad range of applications.

Atomic-absorption (AA) spectroscopy uses the absorption of light to measure the concentration of gas-phase atoms. Since samples are usually liquids or solids, the analyte atoms or ions must be vaporized in a flame or graphite furnace. The atoms absorb ultraviolet or visible light and make transitions to higher electronic energy levels. The analyte concentration is determined from the amount of absorption. Applying the Beer-Lambert law directly in AA spectroscopy is difficult due to variations in the atomization efficiency from the sample matrix, and non-uniformity of concentration and path length of analyte atoms (in graphite furnace of AA). Concentration measurements are usually determined from a working curve after calibrating the instrument with standards of known concentration.

Atomic-absorption (AA) spectroscopy uses the absorption of light to measure the concentration of gas-phase atoms. Since samples are usually liquids or solids, the analyte atoms or ions must be vaporized in a flame or graphite furnace. The atoms absorb ultraviolet or visible light and make transitions to higher electronic energy levels. The analyte concentration is determined from the amount of absorption. Applying the Beer-Lambert law directly in AA spectroscopy is difficult due to variations in the atomization efficiency from the sample matrix, and non-uniformity of concentration and path length of analyte atoms (in graphite furnace of AA). Concentration measurements are usually determined from a working curve after calibrating the instrument with standards of known concentration.

Etiology

Atopic dermatitis is genetically predisposed to allergic skin disease. It consists of atopy and hereditary cause to produce IgE mediated allergic reaction to environmental allergens.

Immunohistochemistry reveals the presence of Langerhans cell proliferation and strong positive expression of IgE in skin tissue sections.

Gross pathology

Pigs are inherently prolific, and two farrowings per year under optimal management conditions should be planned. One boar must be kept for every ten sows for optimal fertility. Breed the animals at their most active heat cycle (12 to 24 hours of heat). After every 21 days, the sows come into heat. Proper feeding and handling promotes heat, which facilitates breeding and results in larger litter numbers. In addition to grains, there is fish meal, skim milk or butter milk feed can be administered 2-3 weeks before breeding to allow for a 200-300 gm/day increase in body weight. The normal gestation period for a sow is 112-115 days, and the usual litter size is 8-10 piglets. Larger litters with higher birth weights are produced by older sows.

Introduction

India pre-dominantly an agriculture-based country, requires constant endeavors to seewhether rural and agricultural credit facilities are enhanced with time. As a part of theseefforts, agricultural credit cards and cash credit facility were introduced in lending system. The Kisan Credit Card is a credit card programme launched by Indian banks in August 1998. The National Bank for Agriculture and Rural Development (NABARD) developed this model scheme to supply term loans for agricultural needs based on the suggestions of the R.V. Gupta Committee. Its goal is to provide financial assistance to farmers in order to address the agricultural sector’s comprehensive credit needs. All commercial banks, Regional Rural Banks, and state cooperative banks are among the participants. Short-term credit limitations for crops are in place, as are term loans. Personal accident insurance covers KCC credit card members up to Rs. 50,000 for death and permanent disability and up to Rs. 25,000 for other risks. The premium is split evenly between the bank and the borrower. The validity period is five years, with the option of an additional three year extension, Kisan Credit Card provides cash and term credit to farmers for a variety of linkedoperations such as pump sets, land expansion, planting, and drip irrigation. Soil Wellbeing Card programming has been institutionalized and online programming built for eight statesunderthee-Government Program to provide coordinated supplement administration suggestions based on soil test edit reaction approach. Ranchers receive data through avariety of channels, including Common Service Centres, Internet Kiosks, and SMS, as partofthe Nationale-Governance Plan for Agriculture. Farmers are spared from the exorbitant interest rates charged by traditional banks under the KCC plan. The interest rate on KCC loans ranges from 2% to 4%. This low interest rate aids farmers in repaying loans more quickly, taking into account the crop’s harvesting season and the date the loan was provide.

Indian agriculture is at demographic, ecological, economic and technological cross-roads. Demographically, nearly 70% of the population is below 35 years in age and 70% of them live in rural areas.  Within the next few decades, India will have the world's largest number of young people looking for employment.  Ecologically the basic life support systems of land, water, forests, biodiversity and climate are in distress and the population supporting capacity of major ecosystems is being exceeded in most parts of the country. India's ecological debt and Nature Deficit Disorder are growing. Economically, the cost-risk-return structure of farming is becoming adverse, with the result that over 40% of today's farmers would like to quit farming, if they had another livelihood option. Technologically, there is a serious mismatch between production and post-harvest technologies. Also, there is no nationally agreed policy towards the technological transformation of agriculture, involving farm mechanization and frontier technologies like recombinant DNA technology and nano-technology.

Indian economy is basically an agrarian economy (Saxena, 2012) and the majority less literate and unskilled population living in rural areas does not fit into the employment market. Employing 55% of labour force, agriculture sector is a major employment provider (Chand, 2014). However, the seasonal nature of Indian agriculture leads to seasonal and cyclical unemployment. This situation can be altered by generating employment opportunities through nurturing entrepreneurship in agriculture (Rehman et al., 2012).

Poor Governance

Bad governance refers to how decisions are made in government and business. It is opposite of good leadership. Poor governance entails systemic corruption and a lack of openness and accountability, arbitrary policymaking, and the deception of those who are ruled.

Atuna racemosa subspecies racemosa is shown to be a species with many uses throughout its range from Malaysia to Melanesia. The principle uses described are the seed oil used as anti-inflamatory massage oil and for hair dressing, the seed pulp that is used for caulking and varnishing boats, the wood for house construction, and many parts of the plant as ingredients of local medicines. The medicinal uses of this species deserve further study since it has been shown to have both anti-bacterial and anti-inflamatory action. It is also uncertain whether its distribution over the Pacific is natural or human caused.

Atuna racemosa Rafin. is a widely distributed tree species that ranges from the Malay Peninsula through Malesia, Australasia and to the Pacific islands as far as Fiji, Tonga and Samoa. As with many useful plants, its natural distribution is uncertain because it has been transported around from island to island during the various migrations of the Pacific islanders.

Audio-visual aids refer to devices that enable both visual and auditory sensory inputs, facilitating enhanced learning and retention compared to using these senses separately. As highlighted in the preceding section, the combination of sight and hearing captures 94% of the audience's attention, underscoring the efficacy of audio-visual aids in extension teaching.

Advantages

• Clarity and Conceptual Understanding: Audio-visual aids convey meaning succinctly and clarify ideas effectively.

• Enhancement of Oral Communication: They supplement spoken words by providing visual reinforcement.

• Stimulation of Conceptual Thinking: They provide a tangible basis for conceptual understanding.

• Engagement and Sustained Interest: These aids attract, arouse, and maintain audience interest.

• Enhanced Learning and Retention: They contribute to long-term retention of learning.

• Overcoming Constraints: They overcome limitations of space, time, and distance.

• Continuity of Thought: Motion pictures aid in the development of coherent thought processes.

• Stimulation of Self-Activity: They stimulate audience participation and motivate action.

Audio-visual aids may be defined as any device used to aid in the communication of an idea. An audiovisual product is any audiovisual item such as still photography, motion picture, audio or video tape, slide or film strip, that is prepared singly or in combination to communicate information or to elicit a desired audience response. Even though early aids such as maps and drawings are still in use, advances in the audiovisual field have opened up new methods of presenting these aids, such as videotapes and other equipments which allow more professional and entertaining presentations to be presented.

Such aids assist the teacher in communicating information among the learners leading to change in skills, attitudes, knowledge, understanding and appreciation. These aids stimulates the sensory organs like ears, eyes, etc and facilitates quick understanding of the message by the audience. The effective use of these aids depends upon the skillful and imaginative approach of the teacher. Hence, it is necessary that extension worker should know what type of aids will be more suitable for a particular teaching objective. These aids may be used for both literate as well as illiterate people.

The instructional devices through which the messages can only be heard are known as Audio Aids. The instructional devices through which the message can only be seen are known as Visual Aids. The instructional devices through which the message can both be heard and seen simultaneously are known as audio-visual aids.

“Audio-Visual aids are those instructional devices that may be used by a communicator in order to facilitate better understanding on the parts of learner by involving their many senses, particularly those relating to seeing and hearing”.
As a potential link between research institutions and livestock owners the extension agent must have good skills in effectively communicating with various stakeholders which include policy makers, researchers, input suppliers, market agents, credit institutions etc.

EXTENSION TOOLS /AIDS

Audio-visual aids, audio-visual media, audio-visual material, communication technology, educational or instructional media, extension teaching aids, extension tools, extension aids, etc, - all these terms broadly speaking, mean the same thing. The use of the terms like educational technology or instructional technology instead of extension tools/aids in the recent time is primarily due to the dynamic expansion of programmed learning, computer assisted instruction and education television. In this discussion, the term audio-visual aid is used most frequently which is almost same as extension aids.

Introduction

Audiotex is a voice response application that allows users to enter and retrieve information over telephone. Example Interactive Voice Response System (IVRS). Audiotex is a generic name for interactive voice response equipment and service. Audiotex connected with a telephone is like a data processor connected to a data terminal. They are passive service which provides through appropriate access by standardised procedure for the user of Audiotex service to communicate with database via telecom network (i.e.) a subscriber can retrieve the information at any time by interacting with the audio service equipment by using the existing telephone line.

Audiotex is essentially a content provider. It enables the subscribers to record their message in a computer memory area called a “Mail Box”. The recorded message can be retrieved by the recipient by dialling a telephone number. Audiotex service is a telecommunication system which enables a caller, by dialling a designated telephone numbering beginning with ‘1800’ to receive a recorded announcement or to interact with a programme whereby he/she may communicate by means of a dual tone multi frequency telephone key pad, a touch tone telephone or other similar device with a value added network connected to the public switched telephone system for purposes of sending or receiving information. However, there are differing views across the world on what constitutes “Audiotex service”. European Telecommunications Standards Institute in its ETSI technical report 131 (June 1994) on “Terminal Equipment(TE); An investigation into the need for standardization in the area of stored voice services” has commented that “ It can be seen that there are many differing views as to what constitutes an Audiotex service and, in formal usage (e.g. in lectures or articles on the subject), a distinction is always drawn between voice messaging and the other services (information, consultation, transaction, etc.). It is thus misleading to use the word Audiotex without a previous definition. Therefore, in many countries the term “stored voice service” is used to describe Audiotex and each separate application and service is distinguished by a more precise definition.

Augmentation strategies are generally used as a way to improve the effectiveness of passive or active frost protection methods. As the intensity of the frost is quite variable and sporadic in nature, simple application of the protection methods is not always helpful in giving adequate protection against freezing stress. 

Nutrition affects the development of human body immune system, playing a vital role in modifying the threat of exposure and susceptibility to infectious patho gens, acuteness of morbidity and success of treatment. Keeping in view the pres ent pandemic and emerging viruses such Eastern Equine Encephalitis, Hantavi ruses, Nipah viruses for which no effective preventive and curative treatment is in hand, a healthy immune system could be one of the most important defences to f ight off (El-Gamal et al., 2011). Vegetables are rich source of essential vitamins, minerals, antioxidants and dietary fibres; however, certain vegetables hold more significance in view of boosting immunity.

Introduction

For many years, it has been acknowledged that “augmentative” or “inundative” biological management can decrease arthropod pests (DeBach, 1964). The goal of increased biocontrol is to bring about behavioral and numerical changes in the natural enemies that live within agricultural environments. This tactic calls for the large production of natural enemies as well as their periodic release, to maximize their potential for reproduction during the growing season. For instance, the use of augmentative releases may be required if naturally occurring populations of parasitoids or pests are either nonexistent, do not successfully colonize fields or orchards, or colonize at a point in the season that is too late to provide effective pest control. The increase is being carried out to establish a population of natural enemies capable of keeping the number of pests at economically hazardous levels until harvesting time.

Biological Control

Controlling problems caused by things like mites, insects, weeds, and plant diseases with the help of other organisms is called biological control or biocontrol. It uses natural mechanisms like predation, parasitism, herbivory, and so on, but human intervention is almost always present.

Parasitoids

The term “parasitoid” refers to a group of insects, the larvae of which develop on or within the bodies of other insects, which the parasitoid kills eventually. The phenomenon is known as parasitism. The vast majority of parasitoids are classified as either wasps (Hymenoptera) or flies (Diptera). These insects are numerically quite abundant and play a significant role in almost every terrestrial environment.

The Preamble of the Indian Constitution promises to all citizens of India social and economic justice apart from political justice and also equality of status and opportunity¹. Although every citizen in India who is more than eighteen years of age, including farmers and agricultural workers have got political justice in as much as they have a right to vote and also contest in elections to the State Legislative Assembly and to the Houses of Parliament, we have not been able to give them social and economic justice, and equality of status and opportunity mainly because they continue to earn income, which are not enough to take care of the essential needs of the family such as food, clothing, shelter, education, health, recreation etc. When the Constituent Assembly adopted the Constitution of India on November 26th 1949, agricultural land was owned by Zamindars and big landlords, and most of the agriculturists were working on their land either as tenants or as agricultural workers. Consequently, most of the citizens of rural India did not own agricultural land and had very little earnings either as tenants or as agricultural workers. 

Youth constitute a numerically dominant potential, resourceful and adventurous segment of the population in India. The share of population between age group 0-14 years dropped from 43% in 1971 to 41% in 1981, however the share of population age 65 has been fairly stable at 3% since 1971. In 1991, youth population in India with the age group of 15 to 35 years was around 31 per cent (246 millions) of the total population.  Out of this total youth population, 20 per cent (53 millions) were urban youth, while the remaining 80 per cent (211 million) were rural (Shivalingaiah, 1995). According to 2001 census, India had a total youth population of 347 millions (i.e. 35.2 per cent of the total population), out of which, about 70 per cent were rural youth and the remaining 30 per cent were urban youth. Since major segment of this population are being lived in the rural areas, they are considered as the nation builders of tomorrow. This important section of the rural population can respond to the needs of country only if they are offered fruitful opportunities for growing up as useful citizens. Today unemployment is a major problem among the rural youth which forced them to migrate from rural areas to urban areas. Indian villages are, therefore undergoing major transformation causing perceptible changes in aspirations of the rural masses, especially the youth. These aspects have been dealt in greater detail in some papers (Sharma, 2006).

Definition

The animal reacts to its own tissue (endogenous antigen) to incite production of antibodies or sensitized lymphocytes. There is breakage of tolerance to the self-proteins.

• Autoimmune diseases are prevented by elimination of sensitized T and B lymphocytes by the process of apoptosis in the thymus and bone marrow during development (Central tolerance; clonal deletion), in the peripheral tissues (Peripheral tolerance) and clonal anergy (Clonal avoidance) by defective presentation of cells.

• The tolerance of CD4+ TH cells is critical in preventing autoimmunity.

• Two major autoimmune diseases are thyroiditis and haemolytic anemia. Other conditions are rare in animals

A. Answer the following.

Q.1.     What is the definition of sequestered antigens ?
Ans.     Sequestered antigens are antigens which are protected from the immune system and no immune response is generated against them. Ex lens and uveal proteins of the eye, chondrocyte antigens in cartilage and antigens of spermatozoa.

Q.2.     What is autoimmune haemolytic anaemia ?
Ans.    It is an antibody mediated autoimmune disease and antibodies are generated against self RBCs. It occurs in unmatched erythrocyte antigen in transfusion or in erythroblastosis fetalis. The antibodies developed in autoimmune haemolytic anaemia are of two types (1) warm autoantibodies (2) cold agglutinins. The warm

One of the characteristics of the immune system is to recognize and discriminate self from the non-self antigens.  But, sometimes, there is a failure to discriminate between self and non-self antigens in the body and an autoimmune response occurs. Body starts producing antibodies against its own cells/antigens. These antibodies are called autoantibodies and this state is called autoimmunity.

One of the characteristics of the immune system is to recognize and discriminate self from the non-self antigens. But, sometimes, there is a failure to discriminate between self and non-self antigens in the body and an autoimmune response occurs. Body starts producing antibodies against its own cells/antigens. The self antigens against which the immune system responds are called autoantigens and the antibodies produced against self antigens are called autoantibodies.

A mill is a device that breaks solid materials into smaller pieces by grinding, crushing, or cutting. Such communition is an important unit operation in many processes. There are manydifferent types of mills and manytypes of materials processed in them. Historically, mills were powered by hand (e.g., via hand cranks) working animals (horsemill), wind (wind mill) or water (watermill). Today they are usually powered by electricity and are controlled by computer (automatic mills).

The grinding of solid matters occurs under exposure of mechanical forces that trench the structure by overcoming of the interior bonding forces. After the grinding, thestate ofthesolid is changed:thegrain size, thegrain size disposition and the grain shape.

Milling also refers to the process of breaking down, separating, sizing, or classifyingaggregatematerial. For instance rock crushingor grindingto produce uniform aggregate size for construction purposes, or separation of rock, soil or aggregatematerialforthe purposesofstructural fillor land reclamationactivities. Aggregate milling processes are also used to remove or separate contamination or moisture from aggregate or soil and to produce “dry fills” prior to transport or structuralfilling.

Grinding may serve the following purposes in engineering: • Increase of the surface area of a solid

• Manufacturing of a solid with a desired grain size

21.1 Automatic Weather Station

Automatic Weather Station, popularly known as AWS, is an electronic device and an automated version of the traditional weather station. Numerous weather sensors are connected to the system which automatically records and stores weather data. It is quite useful in remote areas where no frequent access is possible. The system requires hardware as well as software to log in, store, display, retrieve and analyze the data. The digital data recorded from AWS can be downloaded to the laptop through the memory device. The same digital data can be converted to the actual values indicating various weather parameters through the software provided along with the AWS. It should be also maintained in the desktop of PC/AT so that the data are doubly assured. Every AWS has its own software depending upon the manufactures. Time interval can be fixed for recording weather data depending upon the purpose since it is a continuous recorder. Continuous AWS data are integrated at hourly or half-hourly interval for monitoring weather data, otherwise enormous data are continuously stored and no way are used. Of course, continuous weather display is possible for monitoring weather conditions spatially and temporarily.

Automatic Weather Station consists of a datalogger, rechargeable battery, telemetry (optional) and the meteorological sensors with an attached solar panel. The system may report in near real time via GPRS or save the data for later recovery. Majority of automatic weather stations possesses normally Thermometer Sensor for measuring temperature; Anemometer for measuring wind speed; Wind vane for measuring wind direction; Hygrometer for measuring relative humidity; Barometer for measuring atmospheric pressure; Rain gauge for measuring rainfall and Pyranometer for measuring solar radiation. Automatic weather stations are based around a programmable datalogger that measures the sensors, then processes, stores, and transmits the data. Dataloggers have wide operating temperature ranges, on-board instructions, programmable execution intervals and input channels for commonly used sensors. Wind vector, wet bulb, histogram and sample on maxima or minima are standard in the datalogger instruction sets. Most sensors can be measured directly without external signal conditioning. Data are typically viewed and stored in the units of your choice(e.g., wind speed in mph, m/s, knots). Measurement rates and data recording intervals are independently programmable, allowing calculation of 15 minute, hourly, and daily data values from 1 minute or 1 second measurements, for example. Conditional outputs, such as rainfall intensity and wind gusts, can also be recorded. The program can be modified at any time to accommodate different sensor configurations or new data processing requirements.

Protected structures such as cloches, low tunnels, greenhouses, livestock housing, aquaculture facilities and phytotrones provide varying degrees of climate control for agricultural production. While cloches and low tunnels provide only passive modification of the growing environment, all other protected structures have the possibility of active and precise growing environment control.

GREENHOUSE TECHNOLOGY

Greenhouse technology permits the management of both biotic and abiotic stresses related to plant growth to maximize the productivity and quality. Resultantly, profitability per unit area per unit time increases by two to three orders of magnitude as compared to open field cultivation. Introduction of greenhouse technology in India for commercial production is only about three decades old, whereas it is more than two centuries old in USA, UK, Holland, France, Italy, etc.

A greenhouse is a framed or inflated structure covered with a transparent or translucent material where plant environment could be, at least partially controlled and which is large enough to permit a person to enter and carry out cultural operations. A greenhouse is called a glasshouse, when covered with glass, and plastic house when plastic is the glazing material. Materials of construction and cropping activities are also used to identify greenhouses. In addition to the growing facility, a commercial greenhouse complex has a head house, an input storage and a sales area. All these components are so arranged that unwanted movements of man and material are obviated.The greenhouse complex should have adequate wind breaks on the upstream side of the wind direction to provide protection against heavy winds.

Abdominal part

The sympathetic trunks enter the abdominal cavity between the psoas minor and the crus of the diaphragm of the corresponding side. They run caudally on the ventrolateral surfaces of the lumbar vertebrae and the ventral common vertebral ligament. The left trunk is ventrally related to the abdominal aorta and the right trunk to the caudal vena cava. The sympathetic trunks of the opposite sides in the cranial half of the lumbar part lie rather close to each other and as they pass caudally, they gradually divert from each other. The lumbar sympathetic ganglia are small spindle shaped usually six in number and are present one in each lumbar segment. The first two are larger than the rests. Each is connected with the ventral division of the corresponding lumbar spinal nerve by the ramus communicans. The interganglionic segments of the sympathetic trunk are usually single but some times they split.

Splanchnic nerves

The greater (major) splanchnic nerve is formed by the contribution of sympathetic nerve fibres from fifth or sixth thoracic to thirteenth thoracic sympathetic ganglia. It becomes larger and larger as it passes caudally along with the sympathetic trunk. It enters the abdomen at the level of the first lumbar vertebra gets separated from it, passes ventrally and laterally across the aorta (left trunk) and vena cava (right trunk) to join the coeliacomesenteric autonomic plexus on and around the coeliac and cranial mesenteric arteries.

2.1. Radio

A popular communication medium

2.1.1. Historic features

In India, Madras Presidency Club pioneered radio broadcasting in 1924.

Due to financial difficulties, gave it up in 1927.

In 1927, businessmen in Bombay started Indian broadcasting Company with stations at Bombay and Calcutta.

But, failed in 1930.

Previous Year Questions

1. No questions were asked in past 10 years

Availability of Foodgrains

• Net availability of foodgrains = Gross Production (-) seed, feed & wastage, (-) exports imports (+/-) change in stocks.