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Know your broadband
Pesticide threat Curry leaves for animal fertility Prof Yash
Pal THIS UNIVERSE |
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Know your broadband BROADBAND refers to high-capacity, high speed transmission network that allows people to access online content quickly and dynamically via always accessible internet at work or at home. Broadband gives 24-hour internet services with noise immune digital data transfer. Broadband internet allows subscribers to send or receive voice, audio-video and data content of digital quality. Broadband increases productivity by enabling the transfer of large data files directly from local offices to head offices located in other cities or even in other countries. In such a transmission, several channels can be transmitted using optical fiber, besides other mediums. Service providers can offer a range of services to all types of users, from end users to corporate users. Users can even mix-and-match services from the entire suite of services available. Basic Internet: Basic internet is a base-level service for entry-level customers. Apart from broadband high speed internet service, one can also access a lot of other services such as: multicast, video conferencing, video-on-demand, and gaming. VPN services: It allows dialup, remote access users to access their private networks securely over the backbone infrastructure. The network shall support both client-initiated Virtual Private Network (VPN) as well as network-initiated VPN. So, service providers can provide IP-VPN as well as Multi-protocol Label Switching (MPLS) based VPN services. Wholesale services: This service allows infrastructure to be retailed to other service providers for ISP and VPN services. Here, data ports that are managed by one service provider are to be used by another service provider. The wholesale service providers lease its ports for other service providers, who do not want to set up and manage their own networks.
Technologies ADSL: ADSL stands for Asymmetrical Digital Subscriber Line and it allows copper pairs to be used for providing a broadband connection. ADSL providers always-on internet connection that is automatically established once the personal computer (PC) and ADSL modem are switched on. Hence, one can access Internet as well as telephone calls simultaneously. ADSL is the most rebust and the most mature of all broadband technologies. Incumbent operations in India have deployed ADSL 2+ technology. FTTH: Fiber To The Home (FTTH) is a most ideal technology and both greenfield operators (Reliance and Tata) are deploying it or are in the process of doing FTTH in the top 100 cities to begin with. In the next phase they will spread out to smaller cities. With a large backbone already being deployed by operators, it makes all the more sense to deploy fiber in the last mile and leverage on convergence content. CATV: In developed economies, Cable Television (CATV) is ideal for broadband but in countries like India it is still a dream. Some Multi Service Operators (MSO) do provide Internet access but real broadband speed is still far away. Before CATV is expanded to provide broadband services it has to confront with existing cable operators distributing broadcasting services in the cable industry and a lot of capital investment is also required. At present, CATV operators use OFC in the backbone but OFC in the access part is still a long way to go. One can offer broadband services through CATV using cable modems or set-top boxes. Powerline communication: On October 2004, FCC has adopted rules for broadband over powerline to increase competition and promote broadband services to all American citizens. Access Broadband Powerline (Access BPL) is a new technology that provides access to high speed broadband services using the untapped communications capabilities of the nation’s power grid. This technology will also facilitate the ability of electric utility to dynamically manage the power grid itself, increasing network reliability by remote diagnosis of electrical system failures. G-PON: Gigabit-passive optical networking (G-PON) technology can be used to extend cheap fiber links within metro networks. But, due to cost, no one is suggesting G-PONs for residential fiber. G-PON offers blazing speeds making it ideal for triple-play suites of voice, video and data services for service providers. Its use of Synchronous Optical Network (SONET) framing enables providers to link native Time Division Multiplexing (TDM) and voice connections into the PON without adding IP. Metro Ethernet: At present, there isn’t any successful worldwide model that is extensive in nature. It does have limitations in terms of distance and is good for high-end subscribers, mainly in the corporate world. It is easy for backbone but has lot of problems for last mile. Wireless LAN: Wireless LAN (WLAN) hotspots have been deployed in public places like restaurants, cafes, and convenience stores as well as airports. The new-age speeds are in the range of 5Mbps but this is going to increase in the future. The problem is that today WLAN does not have a business model to attract a large number of subscribers to make it commercially viable.
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Pesticide threat IN the recent Green Revolution decades, Punjab has created very many new folk songs celebrating the tubewell and the tractor. No sad songs have yet been written on the excessive use of pesticides of which Punjab is a major consumer primarily for its cotton and rice crops. Punjab produces 21 per cent of India’s wheat, 9 per cent of rice and 8 per cent of cotton, even though it has less than 2 per cent of India’s land. But, there is also a flip side to this accomplishment. Punjab consumes 12 per cent of India’s agro-chemicals. Quite obviously, any substance that is harmful for insects and pests must be harmful for the human beings also. What is the amount of pesticide in human beings and animals in Punjab? How does it compare with say Uttaranchal Pradesh or Rajasthan? Does the presence of pesticide in the human body cause cancer, mental retardation and other illness? What are the safe limits for human beings? For animals? A large number of players are interested in answers to these and related questions? There are the environmentalist groups, which are no doubt deeply concerned but at times overstate the case. Then there is the government which is the custodian of public health, but tends to get into the defensive mode at the slightest provocation. The profitable agrochemical industry would like to believe that pesticides are not as big a villain as some people are making them out to be, while the companies engaged in the production of genetically engineered crops are hoping that the controversy would help them gain credibility and business. On top of this, while the numerous television channels vie with one another to produce exclusive round-the-clock news, it is not an easy task to maintain a sense of proportion. Conflict of interest and difference in perception are inevitable in any contemporary debate. But the debate should take place in an informed manner. When people take diametrically opposite views on any issue, the decision making becomes erratic. It is therefore essential that differences are narrowed down so that the broad direction in which the decision lies becomes obvious. It is the sacred duty of all participants in the debate to make sure that the scientific methodology is not brought into disrepute. This means that as the very first step, everybody should agree on the basic facts of the case. What is the amount of pesticide present in human beings of different age groups? Does it vary from region to region? Is the amount higher in the cotton belt? Is it higher among the non-vegetarians? Does it vary with seasons? What is the picture in other parts of the country? Ditto for cattle and other animals. It is a simple matter to chemically analyse the composition of blood. In view of the high stakes involved it is imperative that the credibility of the various laboratories remains unquestioned. The first step should be the calibration of participating labs and their equipment. A single blood sample should be divided into sub-samples and given to various labs. No matter what equipment or procedure they employ, no matter who the researchers are, the results should all lie in a permissible range. Once this is ensured, rest of the task is easy. A systematic study, involving government labs, research institutes and universities as well as NGOs, should be carried out. Within the framework of a firm, dependable data-base, different sides can try to convince one another about their point of view. Common citizens, farmers, government, and scientists all would be able to pool their resources and efforts to arrive at a solution. Any problem that is created by human beings must necessarily be solvable by them. What is needed is determination and clear headedness. — The author is Director , National Institute of Science Technology and Development Studies (NISTADS), New Delhi
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Curry leaves for animal fertility A study by scientists at the Indian Veterinary Research Institute (IVRI) in Izatnagar has indicated that curry leaves, the commonly used herb in Indian cooking, can improve animal fertility and the shelf life of meat products. The plant, also known as ‘’meetha neem’’ or ‘’kari patta’’. is commonly grown in kitchen gardens and is found across the country even in altitudes up to 50,000 feet above sea level. Botanically known as Murraya koenigii, the plant is known for several medicinal properties, including reducing blood sugar levels, a boon for diabetics. Results of the research conducted under the direction of IVRI director Dr M.P. Yadav has indicated that oral leaf extract treatment in rats has beneficial effect on onset of puberty, development of the ovarian follicle inside which the egg matures, production of steroids, mating and ovulation. Trials conducted in a limited number of animals like goats, cows and buffaloes also indicated appreciable restoration of fertility with the treatment. Joint director (research) Dr Nem Singh said the scientists are of the opinion that the results may be due to the insulin-like properties of the plant. In many previous researches insulin has been found to augment ovarian function. However, Director Dr Yadav emphasised the need for further research in this area to draw conclusive findings. Another team of IVRI researchers from the Livestock products technology division have found that the use of curry leaves powder as a spice improves the acceptability and shelf life of meat products of old sheep and male pigs. Dr Yadav said the herb has distinctive aromatic, digestive and tonic properties and possess nutritional merit in terms of Vitamin A, calcium and protein.
— UNI
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THIS UNIVERSE I have read that when white light passes through prism, it separates into seven colours. Why doesn’t the same thing happen when white light passes through a simple glass block? What makes a prism special? Let me see if I can explain this phenomenon without using a drawing. I am sure you know that light can be considered a wave of electromagnetic energy. As for any wave, the wavelength of light can be defined as the distance between two neighbouring crests of the wave. The colour we perceive or detect depends on this wavelength. Red light has a wavelength almost twice that violet. White light is a superposition of waves with intermediate wavelengths falling between (and including) violet and red. What a prism does is to destroy this superposition — rays of light of all wavelengths do not fall on our retina on top of each other. Your question in essence asks why this should happen only when a prism and not a flat block of glass is used. When a light wave enters a flat block of glass, the speed of light reduces, with the amount of reduction more for shorter wavelengths. This reduction of speed of wave propagation also produces a change in the direction of motion. This bending is exactly reversed when the light ray re-emerges from the other side of the glass block, provided the emergent edge-face is precisely parallel to the incident edge-face. The bending of direction is different for different colours in transition from air into glass. It also depends on the angle of incidence on the glass. However, on emerging from the glass plate, all colours are again superposed on each other and therefore, there is no dispersion of light — in other words no breaking up into different colours. On the other hand, when we use a prism, because of non-parallelism of the glass faces, the angle of light incidence is necessarily changed (and changed to a different degree for different colours) during exit from the glass surface. There is therefore no longer an exact superimposition of different colours after emergence. That is why we see white light split into its constituent colours that emerge at slightly
different angles. How do the northeast trade winds bring rain to Asia? I suppose you are referring to what we otherwise call our winter monsoons. These winds come from the northeast during winter months in the northern hemisphere. The basic driving force is similar to that for the southwest monsoons that we get during summer — the winds travel from colder regions to hotter ones. The rain comes because the winds often travel long distances over the sea. In our case, most of the moisture is picked up over Bay of Bengal and the southeast coast of the country gets the most rain at the time. For the east coast of the Asian continent, the winds pick up their
moisture over the Pacific Ocean. |
