eChapters

1. Neutron activation analysis

This technique is used in qualitative and quantitative analysis. If an element present in a sample is to be identified by neutron activation analysis, the sample will be bombarded with slow neutrons or other charged particles and converted into radioisotope. It is one of the most sensitive and specific methods available for the determination of trace quantities of a wide range of elements. From the half life measurement, it is possible to identify the element from which the radioisotope has resulted. Also the quantity of element present in a given sample can be calculated by this technique.

Stable isotopes are chemical isotopes that may or may not be radioactive,but if radioactive, have half-lives too long to be measured. These isotopes decay into stable products. Eg. ¹⁴C having 6protons and electrons with 8 neutrons.

Most elements of biological interest (including C, H, O, N, and S) have two or more stable isotopes. Among the stable isotopes, the most useful as biological tracers are the heavy isotopes of carbon and nitrogen.

Radiation emitted from the radioactive isotopes can be detected and quantified by using several equipments and the details are furnished below:

A. Radiation Detection Devices

1. Electroscope

The electroscope is a simple device comprised of a metal rod with two thin leaves attached to one end. If the electroscope is given a negative charge, the metal leaves will separate from each other. It is the characteristic that makes the electroscope useful as a detection device. A negatively charged electroscope will discharge when ions in the air remove electrons from it, and consequently, a positively charged electroscope will discharge when it takes electrons from the air around it. The rate of discharge of the electroscope is a measure of ions in the air and can be used as a basis of measurement and detection.

Radiation Chemistry is a branch of nuclear chemistry that deals with the study of chemical effects of radiation on matter.

Radio activity is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing radiations (a, b, g radiations). It may be of

Chromatography is the set of laboratory techniques used for the separation of molecular mixtures by developing chromatograms. Chromatogram is a collection of different bands on the chromatographic column. The mixture is dissolved in a fluid called the “mobile phase”, which carries with it another material called the “stationary phase”. The various constituents of the mixture travel at different speeds, causing them to separate. Chroma (colour) and graph in (to write) contribute to the word chromatography, as coined by Mikhail Tswett (1903). Solute moves only when it is in stationary phase. In chromatography, the mobile phase flowing into the column is called eluent, the solution emerging from the column is elute, and the process by which solutes moves and separate is called elution.

This method employs the differences in absorbability of components of mixtures and the differences in the mobility rate. The molecules of a substance which interact strongly with the fixed phase will move slowly through the column whereas substances which do not interact strongly are carried through more rapidly. It is used to separate different substances having similar chemical properties.

Absorption and Emission

Absorption techniques – It measures the absorption of abundance of light due to electrons going to a higher energy level.

Emission techniques - It measures the intensity of light that is emitted as electrons return to the lower energy levels.

Colorimetry is the quantitative analysis of a coloured constituent. It is determined by measuring the relative amount of absorption of light passing through a solution of a constituent.

When a monochromatic light is passed through a homogeneous medium, a part of the incident light is absorbed and part of the light is reflected and part could be transmitted. This can be mathematically expressed as

Potentiometry

Potentiometry is based on measurement of potential of an electrode system

Principle

When a metal electrode is immersed in a solution containing its own ions, the metal atom pass into the solution in the form of metal ions and a potential difference is established between the metal and the solution. This potential is called as electrode potential.

Potential on an electrode depends on the ions present in solution and their concentration which can be determined by using electrochemical cells and expressed by Nernst equation

I. Filtration

Filtration is a process of separation of precipitate from solution. Filtration is used to remove impurities from a solution (or) to isolate a solid.

Precipitation

An ionic phenomena wherein the product of the ionic concentrations of a substance in a solution exceeds the solubility product

Precipitate is often ignited before weighing to convert it into substance of definite chemical composition and chemical stability

Compound precipitated –– precipitated form

Example: Magnesium ammonium phosphate

Gravimetric analysis

Techniques – analyte is determined by quantitative isolation of substance by precipitation and weighing the precipitate

Volumetry / Titrimetry

Process of determining the volume of solution of known concentration required to complete reaction with a solution of unknown concentration (test solution) by titration.

Indicator

A substance which indicates the end point on completion of the reaction.

Helps in the visual determination of the completion of titration.

Secondary standard solution

Solution of chemicals which lack one (or) all the properties for a primary standard

A solution standardised by titrating a primary standard

Less accurate than a primary standard

Volumetric Analysis

Measurement of volume of reagents required for the completion of reactions

Also called titrimetry – most widely used techniques of chemical analysis

Rapid, accurate, convenient and inexpensive

Standard solutions

Standard solutions are solutions of accurately known concentration

Different standard solutions are

Laboratory analysis is an important part in any branch of chemistry and analytical chemistry in particular. To undertake the analysis, both apparatus and equipments are needed.

Analytical Chemistry

The science involving the determination of the constituents in terms of elements and compounds is called Analytical Chemistry. It is used to identify the substances found in a material and to quantify the exact amount of substances in them.

The basic principles involved in Analytical Chemistry are changes takes place in the substances by the process of combination, decomposition, replacement and double decomposition.

Astro-meteorology is considered as one of the branches of Astronomy along with Astrophysics, Astrobiology and Astrometry. Astronomy is the science that deals with the material universe beyond the earth’s atmosphere. It studies the nature and constitution of Celestial (heavenly) bodies and the laws which govern them including the effect they produce upon one another. It seeks to unravel the probable past history of heavenly bodies and their development. There exists a confusion between the branches of Astronomy viz., Astrophysics and Astro-meteorology with the term Astrology. Astrophysics uses principles and laws of physics to explain how Celestial bodies form and function or in other words it will help to ascertain the nature of the astronomical objects, rather than their positions or motions in space. However, the Astrology and Astro-meteorology are the subjects deal in future prediction and often considered as pseudo-science which uses position and movement of stars and planets for that purpose. Astrology links these to predict the human behaviour, while that of Astro-meteorology links the same to predict the future weather.

From ancient days, these predictions are based on one’s wisdom and knowledge in astronomy and often these astrologers are astronomers who keenly watch the stars and planets movement and guide their rulers and farmers with their guesstimates. Till date it is being lore, mainly passed to followers of this group and the methodology is not documented clearly and properly. There are many incidences of falsified predictions of astrology as reported by many reviewers elsewhere and we are not discussing the same here, owing to our interest in weather prediction i.e., astro-meteorology only. However, we have to recognize the works of the ancient astrologers who helped in developing the astronomical science.

Basically, there are two approaches in astrology viz., geocentric and heliocentric as used by the practitioner of astrology worldwide. As the name implies the Geocentric astrology is based on the calculation of planetary position as seen by the observer from the earth and thus earth is centre, while Heliocentric astrology bases its interpretation upon position within solar system with reference to the sun as centre. Though in true sense, the sun is the centre, the effect of motion as manifest on the earth is the basis of most astrological interpretation. Hence, vast majority of astrologers employs the geocentric calculations of the planetary positions for their predictions.

Livestock population meet the protein requirement of humans in addition to meeting from plants. The food chain starts from fodder crops to animals and from animals to humans. In human physiology, digestion of plant protein is much easier than animal protein, but however the digestion depends on climate (temperate climate, sub-tropical climate, tropical climate etc.,) wherein human kind live. Similar to crops, there is strong interaction between livestock and meteorological weather elements (temperature, relative humidity, wind etc.). But detailed study has not been published elaborately in scientific journals in the past. The weather elements have greater influence on livestock productivity in terms of milk, meat, skin, wool etc., pest and disease infestation and their housing needs. In this chapter how weather elements influence shed management, pest and disease problem and animals’ productivity and are discussed. In majority of the Veterinary and Animal Science University in India, they have one division on animal climatology, wherein both research and extension aspects are being attended. However, in depth research is the need of the present decade, since little works have been done in the past on animal climatology.

Irrespective of weather elements, the heat stress due to the combination of temperature and relative humidity plays important role in affecting the productivity of animals. There is a range of thermal conditions within which animals are able to maintain a relatively stable body temperature by means of behavioral and physiological means. Heat stress results from the animal’s inability to dissipate sufficient heat to maintain homeothermy (Sejian et al., 2017). High ambient temperature, relative humidity and radiant energy compromise the ability of the animals to dissipate heat. As a result, there is an increase in body temperature, which in turn initiates compensatory and adaptive mechanisms to re-establish homeothermy and homeostasis. Homeostasis refers to the tendency to maintain a balanced or constant internal state that is optimal for functioning. Animals have a specific balanced or normal body temperature. When there is a problem with the internal functioning of animal body, this temperature may increase, signaling imbalance. As a result, body attempts to solve the problem and restore homeostasis for normal body temperature. These readjustments generally referred as adaptations and this is essential for survival of the animals.