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Amplifiers with a single twin-T in the feedback path are analyzed using root locus methods. A design approach has been suggested for realizing high-Q transistorized active filters resulting in a three-transistor configuration with a stable Q of 200. The behavior of parallel and cascade configurations of two twin-Ts are studied with a view to realizing stagger tuned band-pass characteristics. It is found that frequencies of selection of the system are much different from the null frequencies of the two twin-Ts. This behavior is explained using root locus techniques. The difference frequencies for various separations and loop gains have been tabulated. Finally it is concluded that stagger tuning can be realized only by connecting separate high-Q filters in cascade.
The conditions under which the twin-T operates efficiently as the feedback network in transistor circuitry has been analyzed An approach to the design of high-Q transistorized active filters has been suggested resulting in the development of a three-transistor circuit having a Q of over 200 at 10 kc/s.
It has been proved, using the root locus method, that parallel or cascade configurations of two symmetric, balanced twin-Ts in the feedback path of an amplifier, do not result in a double hump type of bandpass characteristic. Such a characteristic is found to be realized only by connecting in cascade separate high-Q selective filters which have been slightly stagger tuned. This results in a characteristic with a very sharp fall and steep skirts. [ABSTRACT FROM AUTHOR]

The article discusses the research on the works relating to child cultural deprivation and cognitive competence. The research observed that disadvantaged children may gain substantially from an enrich environment. A report also noticed that parental expectation was positively related to the child's achievement and intelligence in more than one subcultural group. A definition of intelligence suggests the ability to plan and structure behavior effectively for goal attainment.

The article presents a literary review of the care, training, research, and rehabilitation programs of the mentally retarded in India. Institutions for the training and care of the mentally retarded in India are coming out from the personal efforts of either a committed individual or of a philanthropic organization. Research regarding the mental retardation in the country are categorized into: survey and rehabilitation projects, psychological and educational research, and medical research.

The article discusses the patterns of cognitive ability in nonretarded and retarded children in the U.S. A group of nonretarded and retarded children with matched mental age were given some cognitive tasks of reasoning and memory. It showed that nonretarded children performed the tasks efficiently compared to those who were retarded. Results were factor analyzed for each sample reflecting two modes of coding information, the successive and the simultaneous process

The article presents a study on the efficient search strategies on retarded and nonretarded children based on their visual search, stimulus density and subnormal intelligence. It focuses on the differences in abilities for scanning and information processing which may distinguish those retarded from mental age-matched nonretarded people. Based on the analysis, the groups did not differ either in the initial response time for identifying single words, or in their search time.