A Comparison On The Semen Characteristics And Extenders For Freezing Semen Of The Swamp, River And Crossbred Buffalo (Bubalus Bubalis)

A study was undertaken ( i ) to investigate and compare the effect of chromosome make up on semen characteristics of three buffalo genotypes , viz swamp , 2n=48 ; river 2n=50; and crossbred , 2n=49; ( ii ) to investigate the influence of climate on the semen characteristics of the three genotypes ; (iii) to study the freezability of the semen of the three buffalo genotypes using four different extenders . Theresults showed that in general , the semen quality was better i n the swamp buffalo as compared to the river type. Except for the semen colour, density, volume and spermatozoa concentration , all the other semen characteristics of the crossbred buffalo were inferior to that of the other two genotypes . The lower mean values for mass activity, progressive motility percentage , percent intact acrosome and the higher incidence of total spermatozoa abnormalities in the crossbred buffalo ( 2n=49) semen indicate that the odd number chromosome complement of this genotype has an adverse effect on its semen characteristics

Membrane mediated aggregation of curvature inducing nematogens and membrane tubulation

The shapes of cell membranes are largely regulated by membrane associated, curvature active, proteins. We use a numerical model of the membrane with elongated membrane inclusions, recently developed by us, which posses spontaneous directional curvatures that could be different along and perpendicular to its long axis. We show that, due to membrane mediated interactions these curvature inducing membrane nematogens can oligomerize spontaneously, even at low concentrations, and change the local shape of the membrane. We demonstrate that for a large group of such inclusions, where the two spontaneous curvatures have equal sign, the tubular conformation and sometime the sheet conformation of the membrane are the common equilibrium shapes. We elucidate the factors necessary for the formation of these {\it protein lattices}. Furthermore, the elastic properties of the tubes, like their compressional stiffness and persistence length are calculated. Finally, we discuss the possible role of nematic disclination in capping and branching of the tubular membranes.Comment: 15pages, 8 figure

Recent Developments in Powder Metallurgy of Non-ferrous Metals

The scope of this paper is limited to the developments in powder metallurgy in the field of porous materials, high strength high temperature materials and continuous compaction of metal powders

Recent Developments in power Metallurgy of non-ferrous Metals

THE first large-scale application of powder metallurgical techniques started with the production of ductile tungsten -a non-ferrous metal, by W. D. Coolidge in 1910. This date can be considered as the renaissance of powder metallurgy, because this invention was the basis for the development of the modern incandescent lamp industry. In this context one has to forget about the prehistoric and primitive powder metallurgy as well as the production of sintered platinum by the British and Russians in the first half of the 19th century. The development of ductile tungsten led to large scale production of refractory metals such as tungsten , molybdenum ; contact materials, such as tungsten- copper, tungsten-silver : porous products. such as bearings, filters and also cemented carbides. These materials could not be produced by the conventional techniques. Later developments include the high temperature high strength materials, such as cermets, dispersion hardened materials and fibre rein-forced composites The entry of powder metallurgy into the competitive field for the production of structural parts and semi-finished products by the continuous compaction of metallic powders is a remarkable one. Today powder metallurgy process can compete on equal terms with other processes. It is no longer the last resort. Among the various methods available for the processing of metals, powder metallurgy occupies a unique place. It can he used not only for making a variety of products for different applications like other methods, but also to create new materials which are either difficult or impo-ssible by the conventional techniques

Increasing population and declining biological resources in the context of global change and globalization

In the context of over-consumption of natural resources in the name of development and rapid industrialization by a small section of the human population that is rapidly growing, the world is currently faced with a variety of environmental uncertainties. 'Global change' covering a whole variety of ecological issues, and 'globalization' in an economic sense, are two major phenomena that are responsible for these uncertainties. There is increasing evidence to suggest that the developing countries more than the developed, particularly the marginalized traditional (those living close to nature and natural resources) societies would be the worst sufferers. In order to cope with this problem in a situation where the traditional societies have to cope with rapidly depleting biodiversity on which they are dependant for their livelihood, there is an urgent need to explore additional pathways for sustainable management of natural resources and societal development. Such pathways should be based on a landscape management strategy, that takes into consideration the rich traditional ecological knowledge (TEK) that these societies have. This is critical because TEK is the connecting link between conservation and sustainable development. This paper explores the possibilities in this direction through a balanced approach to development, that links the 'traditional' with the 'modern', in a location-specific way

The science behind rotational bush fallow agriculture system (jhum)

Rotational bush fallow agriculture variously termed as shifting agriculture, slash and burn agriculture are commonly known in India as jhum is a traditional agricultural system of the humid tropics and is extensively practised by the tribes of the north-eastern hill region. There is a renewed interest in this agricultural system as it has so much to offer in terms of concepts and ideas to modern agricultural organization. The science behind jhum is based on intuitive experience of the farmer based on long tradition. This paper looks at the science behind jhum with particular emphasis on the ecological and economic significance of mixed cropping, recycling of resources within the system and between jhum and animal husbandry, the non-weed concept weed potential under different cycles of jhum, and nutrient cycling. The distortions brought about by the shortening of the jhum cycle to 4-5 yr is considered. Alternate strategies for development with jhum as the focal point, with suitable modifications but without the present-day distortions, have been considered

Sustainable mountain development: The Himalayan tragedy

Mountain systems in India, including the Himalayan region are characterized by highly complex socio-ecological systems, with rich cultural diversity linked with equally rich species of biological diversity. With a large number of ethnic societies having their own social, economic and cultural attributes placed in a highly heterogeneous mountain environment, any conservation-linked developmental initiative has to be based upon a value system that they understand, appreciate and therefore can participate. While textbook-based 'formal knowledge' has its value in this effort, the rich traditional ecological knowledge (TEK) derived through an experiential process and available with local communities forms a powerful connecting link between ecological and social systems. Converting TEK, often seen as location-specific into broad generalizations that are applicable across socio-ecological systems was the major step that was undertaken by this author to convert research results into policy formulations and developmental initiatives, as illustrated here. In the ultimate analysis, developmental initiatives that link cultural diversity with biological diversity are seen as the basis for ensuring human security in these socio-ecologically fragile mountain systems