Causation and correlation

I was a little confused when one of my friends warned me that I am confusing correlation and causation in response to my post on Facebook. It was in my mind for quite a few months now. In fact I was trying to find an answer whether I was actually confusing. When I thought of correlation, the first thought that came to my mind was that of good old school days. The weather was not so deceiving those days. Whether the school reopens on first, second or third of June, the beginning of the rainy season exactly coincides with the reopening of schools and we will be all soaked in rain on that evening. But we used to enjoy the first rain of the season and the first day of the school year on the same day. So we can easily draw out a correlation between the two. The same is repeated every year. But does it actually imply that one of them caused the other? I should say, we cannot conclude that one of them caused the other. Let us consider another example. Every time I switched on the switch my lamp glows. As in the previous case, we may derive a correlation between the two events. Here I can definitely conclude that switching on the switch causes the lamp to glow. So how can I ascertain whether the correlation derived can be verified to be the cause?

Generally, if one factor (A) is observed to only be correlated with another factor (B), it is sometimes taken for granted that A is causing B, even when no evidence supports it. This is a logical fallacy because there are at least five possibilities: First possibility is that A may be the cause of B. Second one is B may be the cause of A. Third possibility is some unknown third factor C may actually be the cause of both A and B. The next possibility is there may be a combination of the above three relationships. For example, B may be the cause of A at the same time as A is the cause of B (contradicting that the only relationship between A and B is that A causes B). This describes a self-reinforcing system. The fifth one is that the "relationship" is a coincidence or so complex or indirect that it is more effectively called a coincidence (i.e. two events occurring at the same time that have no direct relationship to each other besides the fact that they are occurring at the same time). A larger sample size helps to reduce the chance of a coincidence, unless there is a systematic error in the experiment.

Since the 1950s, both the atmospheric CO2 level and obesity levels have increased sharply. If we conclude atmospheric CO2 causes obesity or vice versa, it is a false conclusion. Richer populations tend to eat more food and consume more energy. The two are having no impact on one another. If a person having an ailment is taking medicine and praying and got cured, if you conclude that the cure is due to praying is a false conclusion since not all people pray are not cured. The conclusion that the cure is because of taking medicine is a more logical one. However, since not all people taking medicine are cured, there might be other factors which are important.

Consider a weight suspended by a string. If you cut the string, the weight will fall down. If you repeat the experiment again and again, the same will happen. So we can conclude that the action of cutting the string cause the weight to fall down. The cause of the event is established beyond doubt. Now let us examine the event again. If the string is not cut, the weight will not be falling down, which means cutting of the string is the cause. But even if the string is cut, if gravitational force is absent, if would have remained in its position which leads us to the conclusion that the gravitational force is the cause. Again if you observe the act of cutting the string, the string is cut because we applied a force, which means that the application of force is the cause. Even if you apply the force, if the knife was not sharp, the string would have remained intact and that renders the sharpness of the knife as the cause. Again we were able to cut the string with a sharp knife because the knife is harder than the string. In short the perspective of the person observing the event also is crucial. It will be illogical to conclude any one of the above as the cause of the event. A more logical conclusion is to acknowledge all of the above as the cause of the event.

Another example is the observation that as ice cream sales increase, the rate of drowning deaths increases sharply. Therefore, ice cream consumption causes drowning. The example fails to recognize the importance of time and temperature in relationship to ice cream sales. Ice cream is sold during the hot summer months at a much greater rate than during colder times, and it is during these hot summer months that people are more likely to engage in activities involving water, such as swimming. The increased drowning deaths are simply caused by more exposure to water-based activities, not ice cream. The stated conclusion is false.

Much of scientific evidence is based upon a correlation of variable – they are observed to occur together. Scientists are careful to point out that correlation does not necessarily mean causation. The assumption that A causes B simply because A correlates with B is often not accepted as a legitimate form of argument. However, sometimes people commit the opposite fallacy – dismissing correlation entirely, as if it does not suggest causation. This would dismiss a large swath of important scientific evidence.

In conclusion, correlation is a valuable type of scientific evidence. But first correlations must be confirmed as real, and then every possible causative relationship must be systematically explored. In the end correlation can be used as powerful evidence for a cause and effect relationship between a treatment and benefit, a risk factor and a disease, or a social or economic factor and various outcomes. But it is also one of the most abused types of evidence, because it is easy and even tempting to come to premature conclusions based upon the preliminary appearance of a correlation.

The Water Bomb

Mullaperiyar Dam  is a masonry gravity dam on the Periyar River. It is located 881 m (2,890 ft) above mean sea level in Idukki District of Kerala. It was constructed between 1887 and 1895 by the British Government to divert water eastwards to Madras Presidency area (the present-day Tamil Nadu). 

 

The Mullaperiyar Dam is a gravity dam made with limestone and surkhi (a mixture of crushed brick, sugar and quicklime). Gravity dams use their weight and the force of gravity to support the reservoir and remain stable. The main dam has a maximum height of 53.6 m (176 ft) and length of 365.7 m (1,200 ft). Its crest is 3.6 m (12 ft) wide while the base has a width of 42.2 m (138 ft). It consists of a main dam, spillway on its left and an auxiliary dam (or "baby dam") to the right. Its reservoir can withhold 443,230,000 m3 (359,332 acre·ft) of water, of which 299,130,000 m3 (242,509 acre·ft) is active (live) storage.

 

On 29 October 1886, a lease indenture for 999 years was made between the Maharaja of Travancore, Visakham Thirunal Rama Varma  and the British Secretary of State for India for Periyar Irrigation Works, after 24 years negotiation between the Maharaja and the British. One may wonder how can a lease agreement of  999 years  be made for a dam with a design life of 50 years. The lease indenture granted full right, power and liberty to the Secretary of State for India to construct make and carry out on the leased land and to use exclusively when constructed, made and carried out, all such irrigation works and other works ancillary thereto to. The agreement gave 8000 acres of land for the reservoir and another 100 acres to construct the dam. The tax for each acre was INR 5 per year. The lease provided the British the rights over "all the waters" of the Mullaperiyar and its catchment basin, for an annual rent of INR 40,000. 

 

Mullaperiyar dam was constructed to provide water to the rain shadow region of Madurai which was in dire need of a greater supply than the small Vaigai River could give. The dam created the Periyar Thekkady reservoir, from which water was diverted eastwards to via a tunnel to augment the small flow of the Vaigai River. The Vaigai was dammed by the Vaigai Dam  to provide a source for irrigating large tracts around Madurai. As per the original lease agreement, the dam waters were used only for the irrigation of 68,558 ha (169,411 acres). Later, the Periyar Power Station in the lower Periyar, Tamil Nadu was built which generates hydro-electricity  (175 MW capacity) from the diverted waters in the Periyar Power Station constructed in 1956. This was the first violation of the original lease agreement. 

 

In 1947, after Indian Independence, the lease agreement expired. After several failed attempts to renew the agreement in 1958, 1960, and 1969, the agreement was renewed in 1970 when C Achutha Menon was Kerala Chief Minister. It was a blunder to renew the agreement due to two reasons. 

1. The design life of the dam was 50 years. The dam constructed in 1895 has already served the cause for 75 years.
2. Tamil Nadu has already violated the original lease agreement by generating electricity from the the diverted water since 1956.

 Instead of canceling the agreement and negotiating a new one, the Government of Kerala accepted the agreement as such with minor modification in the lease amounts. 

According to the renewed agreement, the tax per acre was increased to INR 30, and for the electricity generated in Lower Camp using Mullaperiyar water, the charge was INR 12 per kiloWatt per hour. Tamil Nadu uses the water and the land, and the Tamil Nadu government has been paying to the Kerala government for the past 50 years INR 2.5 lakhs as tax per year for the whole land and INR 7.5 lakhs per year as surcharge for the total amount of electricity generated. The validity of this agreement  and several other  issues are under dispute between the States of Kerala and Tamil Nadu. The matter is currently pending before a Division Bench of the Supreme Court.

 

The dam is an 'endangered' scheduled dam under the Kerala Irrigation and Water Conservation (Amendment) Act, 2006. The dam and the river are owned by and located in Kerala. But the dam is controlled and operated under a period lease by Tamil Nadu state. The safety of the dam has been a matter of concern. Control and safety of the dam and validity and fairness of the lease agreement have been points of dispute between Kerala and Tamil Nadu states.

 

After the 1979 Morvi Dam failure which killed up to 25,000 people, safety concerns of the aging Mullaperiyar dam's and leaks and cracks in the structure were raised by Kerala Government. Centre for Earth Science Studies (CESS), Thiruvananthapuram found out that the structure would not withstand an earthquake above magnitude 6 on the Richter scale. The dam was also inspected by the Chairman of Central Water Commission. On the orders of the CWC, the Tamil Nadu government lowered the storage level from 142.2 feet to 136 feet, conducted safety repairs and strengthened the dam. Strengthening measures adopted by Tamil Nadu PWD from 1979 onwards include cable anchoring of the dam's structure and RCC backing for the front slope. The mistakes in the strengthening works carried out by Tamil Nadu damaged the masonry of the dam.

Current safety concerns hinge around several issues. Since the dam was constructed using stone ruble masonry with lime mortar grouting following prevailing 19th century construction techniques that have now become archaic. Seepage and leaks from the dam have caused concern. Moreover, the dam is situated in a seismically active zone. An earthquake measuring 4.5 on the Richter scale occurred on June 7, 1988 with maximum damage in Nedumkandam and Kallar (within 20 km of the dam). Consequently several earthquake tremors have occurred in the area in recent times. These could be reservoir-induced seismicity, requiring further studies according to experts. CESS, IIT Roorkee and IISc have reported that the dam cannot withstand earthquakes above 6 point on the Richter scale.

Kerala did not object giving water to Tamil Nadu. Their main cause of objection is the dams safety as it is as old as 116 years. Increasing the level would add more pressure to be handled by already leaking dam. Tamil Nadu wants the 2006 order of Supreme court be implemented so as to increase the water level to 142 feet (43 m).

In September 2009, the Ministry of Environment and Forests of Government of India granted environmental clearance to Kerala for conducting survey for new dam downstream.  Tamil Nadu approached Supreme Court for a stay order against the clearance; however, the plea was rejected. Consequently, the survey was started in October, 2009. On Sept. 9, 2009 stated it had already communicated to the Government of India as well as to the Government of Kerala that there is no need for construction of a new dam by the Kerala Government, as the existing dam after it is strengthened, functions like a new dam. This is in fact the first water dispute which does not involve dispute on the quantity of water supplied.

What we should do next?

Precautionary Principle is a philosophical approach to risk prevention by taking protective measures against specific  environmental or safety hazards in order to avoid or reduce environmental or safety risks. This approach was subsequently adopted in various International agreements. Precautionary Principle must be invoked

• Where the scientific evidence for safety is insufficient, inconclusive or uncertain.
• Where preliminary scientific evaluation suggests that effects on the environment, health or safety may be unacceptable and/or inconsistent with the chosen level of protection.
• Precautionary principle may be applied without waiting for the reality and seriousness of those risks to become fully apparent.

This principle was laid down in the Rio de Janeiro Declaration on Environment and Development of the United Nations Conference on Environment and Development (1992), in which India is a signatory. The due jurisprudence implied in the Rio instruments are international in impact and it cannot be violated by signatories like India.

Moreover, a number of important international conventions have incorporated this principle, including conventions on Climate Change and Biological Diversity. The Periyar National Park in Thekkady, a Protected area of Kerala, is located around the dam's reservoir, the 26 sq. km (10 sq mi) Periyar lake. 62 different kinds of mammals have been recorded in Periyar, including many threatened ones. Periyar is a highly protected tiger reserve and elephant reserve. There are an estimated 53 tigers (2010) in the reserve. The elephant number around 900 to 1000 individuals. Other mammals found here include gaur, Bison, sambar (horse deer), barking deer, mouse deer, Dholes (Indian wild dogs), mongoose, foxesand leopards. Also inhabiting the park, though rarely seen, are the elusive Nilgiri tahr. Four species of primates are found at Periyar - the rare lion-tailed macaque, the Nilgiri Langur, the commonlangur, and the Bonnet Macaque. According to a report by the Kerala Forest Research Institute, the protected area surrounding the dam and reservoir is classified as a biodiversity hot spot.

 “States....must not wait for proof of harmful effects before taking action” (1984 Bermen Ministerial Declaration of the International Conference on the Protection of the North Sea)· “The parties should take precautionary measures to anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects. Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing such measures” (1992 Framework for Convention of Climate Change, Art 3(3)).

 

Former Judge of Supreme Court Sri. V.R. Krishna Iyer, a great humanist, had invited the attention of the nation through an article in Hindu daily published in last year. In that article he pointed out that “Mullaperiyar is a classic instance where the precautionary principle of action cannot wait for a public calamity to happen. The nation as a whole must raise its voice against a possible natural calamity involving Mullaperiyar.”

 

He also cited a recent judgment of Supreme Court of India in M.C. Mehta v. Union of India (AIR 2004 SC 4033): “In such matters [involving actions that pose a threat of serious or irreversible damage], many a time the preferable option is not clear. If an activity is allowed to go ahead, there could be irreparable damage to the environment; if it is stopped, there could be irreparable damage to economic interests. In case of doubt, however, protection of environment should take precedence over economic interest. The Precautionary Principle requires anticipatory action to be taken to prevent harm. This harm can be prevented even on a reasonable suspicion. It is not always necessary that there should be direct evidence of harm to the environment.”

 

Nothing in life is entirely risk free, and indeed science cannot demonstrate freedom from risk, particularly from as yet known risks, because ‘absence of evidence’ is not ‘evidence of absence’! There are situations where engineers may disagree with one another. Some experts may consider the condition of a dam to be marginally safer than what others say it is. But nature has its own way, and experts’ expectations and calculations may go awry. Once there is reasonable apprehensions about the imminent danger and the possibility of a risk, the state should not take any chances. 

Boyds Corner Dam is the first concrete dam built in USA in 1872. In 1980s, after the collapse of Tenton Dam, it was decided to review the condition of that dam. There was divided opinion on the safety of the dam. Some strongly believed that it was safe while others believed  that it was unsafe. Despite opposition, the Government of USA decided to construct a new dam and the Boyds Dam was demolished and rebuilt in 1990.

Decommissioning of Old Victoria dam in Australia is an example of how a century old unsafe dam of almost the same age and built using similar technology as that of Mullaperiyar dam was treated in a developed country. This dam was constructed in 1891 with lime concrete like Mullaperiyar dam in 1895.  In 1966, the Dam witnessed lot of seepages, which is also the case in Mullaperiyar dam. Certain strengthening measures were carried out to the Victoria dam, which were found to be inadequate in 1988. Therefore the authorities concerned decided to decommission the dam in April 1990. In its place, a new Victoria dam has already been constructed, which now supplies drinking water to the city of Perth.

 

 The water bomb started ticking long back. The question is whether it is now or later. We have no time to debate. Act wisely. Use precautionary principles. Decommission the dam. It is pretty old. Let it retire. And construct the new dam as early as possible. And let the people down stream have a peaceful life.

Courtsey: 
1. James Wilson,  Assistant Executive Engineer (Civil), Kerala State Electricity Board. (Presently working as a member of the Mullaperiyar Special Cell, Government of Kerala on deputation. Associated with Mullaperiyar case since 2006.)
2. Wikipedia

Jaitapur - A guinea pig for untested reactor?

The Japanese are the world’s experts in earthquake-resistant designs. Japan is a country that has a very good disaster management organisation throughout their nation. They often rehearsed working team to handle such emergencies. In contrast, in India, we are most disorganised and unprepared for the handling of emergencies of any kind of even much less severity. The Atomic Energy Regulatory Board’s (AERB’s) disaster preparedness oversight is mostly on paper and the drills they once in a while conduct are half-hearted efforts.

In case of earthquake engineering, the strategy of Nuclear Power Corporation is to have their favourite consultants cook up the kind of seismic data which suits them, and there is practically no independent verification of their data or design methodologies. A captive AERB, which reports to the Department of Atomic Energy (DAE), makes the overall nuclear safety management in India worthless. Today, the AERB merely serves as a lap dog of the DAE and the prime minister’s office (PMO).

When that happens, dangerous species of radioactive fission products in the gaseous and micro-dust and droplet form could spread over large areas, depending on wind conditions. Even a millionth gram of some of these substances, if ingested or breathed in, could seriously raise the cancer risk for individuals, especially in children and infants.

It is true that it is unlikely that the kind of a devastating earthquake and tsunami that hit Japan may strike any of the Indian nuclear plants. But the earthquake-resistant designs and tsunami abatement measures we have taken in our nuclear plants need a high-level, in-depth review by an independent expert group, predominantly consisting of non-DAE, non-NPCIL (Nuclear Power Corporation of India Limited) experts. Ever since the UPA government has taken over in 2004, the collusion between the PMO, the DAE, NPCIL and the various corporate houses in India and abroad has substantially increased. This closeness was deliberately engineered by the PMO, initially to bring home the Indo-US nuclear deal, but afterwards the continuity of this closeness between the corporate business houses interested in nuclear power and the concerned supervisory government agencies is distorting and damaging independent government decisions to be taken in the public interest, whether it be in the choice of import of reactors and their cost, the environmental impact of such imported reactors, or their potential deficiencies and dangers. This is certainly fast leading this country towards large economic losses and a sharp increase in the potential for hazardous reactor accidents in India.

India has built 18 Pressurized Heavy Water Reactors (PHWRs) on our own. We have mastered the design through carefully learning from the mistakes of the past, and are currently moving on to build 700 MWe units of this type. We have three generations of Indian engineers who are familiar with the PHWR. If we need more nuclear power, the safest route is to consolidate and expand on our PHWR experience, import natural uranium, and build more PHWRs. Instead, the government is scattering our energies and talent in getting imported reactors like the French EPRs in Jaitapur, of which neither Indians nor the French know much about. If, in a PHWR, a major accident occurs, we have Indian engineers and scientists who are totally familiar with the details, who can jump in and rapidly bring the situation to normal. For Indian engineering teams to react in a similar timely and effective manner against an accident in one of the planned imported reactors will be next to impossible for at least few decades to come.

The first objection is that the Evolutionary Pressurized Reactors (EPRs) to be built in Jaitapur, having not been commissioned anywhere in the world, is a non-existent reactor whose potential problems are totally unknown even to Areva, its developer, let alone India’s Nuclear Power Corporation. A reactor has to be physically built and then only it can be tested, and the EPR is therefore a totally untested reactor, even if Areva claims they have combined various best design features on paper in conceiving the EPR. The reliability and safety of EPR will be extremely low and unknown until, through different stages of operation and testing over years, all indicated problems are rectified.

Why should people of Jaitapur be subjected to the high risk of providing an unknown reactor in their backyard? This decision of the government is all the more perplexing when we know that India has already built about 18 PHWRs on its own over the last four decades and has perfected its design through extensive years of operation, and we can continue to expand nuclear power in India by setting up more 700 MWe PHWRs of our own design.

Secondly, the promoters (NPCIL & Areva) are totally silent about the serious problems that India, and especially the local community, has to face after operations start and the spent-fuel starts accumulating at the site. The higher burn-up spent fuel from EPRs has its own unique hazards at the storage and transportation stages, unlike in the case of current LWRs, which use lower burn-ups. Besides, the reprocessing of such fuel will be extremely complex, the per MWh production of usable plutonium from this plant will be notably low, and these two reasons combined will make EPRs least useful as plutonium producers for India’s move through indigenous thorium-based fast breeders for the future.

Thirdly, we are buying into all these high risks at an enormous cost to the tax payers. An EPR will cost no less than Rs. 20 crore per MWe, if the government does not hide much of the costs through invisible subsidies. As against this, an Indian PHWR will cost at the most Rs. 8 crore per MWe. Why not purchase natural uranium alone from abroad and multiply the number of 700-1000 MWe PHWRs, for which India does not require any technology imports?

Even in the evaluations and negotiations of cost, the safety and liability of imported reactors, the official nuclear agencies today are operating hand-in-glove with their friends in the corporate houses and federations. Under the circumstances, these government agencies must be visibly de-linked from corporate influences first and made truly independent, before the public can be expected to believe any of their assertions.

Courtsey: Dr A Gopalakrishnan, former chairman, Atomic Energy Regulatory Board, Government of India

For Further reading:

• Pressurised heavy water reactor (PHWR)
•  Evolutionary Power Reactor or European Pressurized Reactor (EPR)

Endosulfan Banned???

The Conference of Parties to the Stockholm Convention in Geneva on last Friday approved the recommendation for elimination of production and use of endosulfan and its isomers worldwide, subject to certain exemptions. The actual decision is to list technical endosulfan and related isomers in Part I Annex A to the Convention with specific exemptions for production as allowed in the Register of Specific Exemptions and/or use on crop-pest complexes as listed with the decision. This would require 173 countries, which are parties to the Convention, to take steps for a ban on production and use of endosulfan. However, exemptions will be available for five years, extendable for another five years. The listing takes one year to be effective.

Exemptions will be available for application of endosulfan against 44 pests in 22 crops — cotton, jute, coffee, tea, tobacco, cowpeas, beans, tomato, okra, eggplant, onion, potato, chillies, apple, mango, gram, arhar, maize, paddy/rice, wheat, groundnuts and mustard. The pests include aphids in most of the exempted crops, bollworms, jassids, whiteflies, thrips and leafroller in cotton, Bihar hairy caterpillar and yellow mites in jute and berry borer and stem borer in coffee. For tea, application of endosulfan is allowed for a host of pests including caterpillars and tea mosquitoes. Endosulfan will be allowed to be used against hopper and fruit fillies in mango and several pests in tomato. In rice, use will be permitted against white jassids, stem borer, gall midge and rice hispa and in wheat against termites and pink borer, besides aphids. 

Many of these crops are commonly cultivated in India. Nevertheless, we do not have control on the use of the pesticides. It is impossible in a country like ours to track down the use of the pesticides. Even though the ban is in force, on the use of this pesticide on other crops, we will not be able to have control on its use. In this circumstances, the ban remains only procedural. It is required to have an immediate and complete ban of Endosulfan.

Civil Engineering Notes

Hi,
The Notes on Engineering Mechanics and Design of Steel Structures posted here is moved to an independent blog for Civil Engineering Notes. You can access the contents using the link : http://ce-notes-vg.blogspot.com/ .
Please follow the link to access the blog : Civil Engineering Notes by Vaisakh G .

THE LEANING TOWER

The Leaning Tower of Pisa (Torre pendente di Pisa) or simply the Tower of Pisa is the campanile (freestanding bell tower) of the cathedral of the Italian city of Pisa. It is situated behind the Cathedral and is the third oldest structure in Pisa's Cathedral Square (Piazza del Duomo) after the Cathedral and the Baptistry. The height of the tower is 55.86 m (183.27 ft) from the ground on the low side and 56.70 m (186.02 ft) on the high side. The width of the walls at the base is 4.09 m (13.42 ft) and at the top 2.48 m (8.14 ft). Its weight is estimated at 14,500 metric tons (16,000 short tons). The tower has 296 or 294 steps; the seventh floor has two fewer steps on the north-facing staircase.

Construction of the tower occurred in three stages across 177 years. Work on the first floor of the white marble campanile began on August 8, 1173, during a period of military success and prosperity.

Due to a mere three-metre foundation, set in weak, unstable subsoil, a design that was flawed from the beginning, the tower began to sink after construction had progressed to the third floor in 1178. The tower would almost certainly have toppled if the construction was not halted for almost a century, because of continuous battles. This allowed time for the underlying soil to settle.

In 1272 construction resumed under Giovanni di Simone, architect of the Camposanto. In an effort to compensate for the tilt, the engineers built upper floors with one side taller than the other. Because of this, the tower is actually curved. Construction was halted again in 1284, due to the defeat of Pisans in the Battle of Meloria. The seventh floor was completed in 1319. It was built by Tommaso di Andrea Pisano, who succeeded in harmonizing the Gothic elements of the bell-chamber with the Romanesque style of the tower. There are seven bells, one for each note of the musical major scale. The largest one was installed in 1655. The bell-chamber was finally added in 1372. In 1987 the tower was declared as part of the Piazza del Duomo UNESCO World Heritage Site along with the neighbouring cathedral, baptistery and cemetery.

A multinational task force of engineers, mathematicians and historians gathered on the Azores islands to discuss stabilization methods. It was found that the tilt was increasing in combination with the softer foundations on the lower side. Many methods were proposed to stabilize the tower, including the addition of 800 metric tonnes of lead counterweights to the raised end of the base.

On January 7, 1990, after over two decades of stabilization studies, the tower was closed to the public. The bells were removed to relieve some weight, and cables were cinched around the third level and anchored several hundred metres away. Apartments and houses in the path of the tower were vacated for safety. The final solution to prevent the collapse of the tower was to slightly straighten the tower to a safer angle, by removing 38 cubic metres (50 cu yd) of soil from underneath the raised end. The tower was straightened by 18 inches (45 centimetres), returning to its 1838 position. After a decade of corrective reconstruction and stabilization efforts, the tower was reopened to the public on December 15, 2001, and was declared stable for at least another 300 years.

Prior to restoration work performed between 1990 and 2001, the tower leaned at an angle of 5.5 degrees, but the tower now leans at about 3.99 degrees. This means that the top of the tower is displaced horizontally 3.9 metres (12 ft 10 in) from where it would be if the structure were perfectly vertical.

In May 2008, after the removal of another 70 metric tons of earth, engineers announced that the Tower had been stabilized such that it had stopped moving for the first time in its history. They stated it would be stable for at least 200 years. After a phase (1990–2001) of structural strengthening, the tower is currently undergoing gradual surface restoration, in order to repair visual damage, mostly corrosion and blackening. These are particularly pronounced due to the tower's age and its exposure to wind and rain.

Two German churches have challenged the tower's status as the world's most lop-sided building: the 15th-century square Leaning Tower of Suurhusen and the 14th century bell tower in the town of Bad Frankenhausen. Guinness World Records measured the Pisa and Suurhusen towers, finding the former's tilt to be 3.97 degrees.

In June 2010, the Guinness Book of World Records certified Capital Gate as the “World’s furthest leaning man-made tower.” The new record shows that the Capital Gate tower has been built to lean 18 degrees westwards; more than four times that of the world famous Leaning Tower of Pisa. Investigation and evaluation, which was made by a Guinness appointed awards committee, started in January 2010, when the exterior was completed.

Capital Gate’s construction commenced in September 2007; the tower’s completion is scheduled for late 2010. From its foundations right through its pinnacle, Capital Gate is a unique building and among the most technically challenging engineering projects in the world. Some key features stand out amongst others are (i) It’s gravity-defying 18 degree lean, widely believed to be the most inclined in the world (ii) The continuous twist of its form which ensures that the tower looks different from every angle (iii) The unique nature of the floor plate, each floor is unique

The foundation contains an incredibly dense mesh of reinforced steel that sits above 490 piles, drilled 30 meters underground to accommodate gravitational, wind and seismic pressures.

The core of the building is a pre-cambered, ‘slanting’ core that pulls in the opposite direction to the lean. It straightens as the building grows, pulled into a vertical position by the change in the centre of gravity of the building as concrete was poured onto subsequent floors.

The floor plates up to the 12th level are stacked vertically over one another. Between levels 12th and 29th the floor plates stagger over each other, in relation to the lean and twist of the shell, by between 800 to 1400mm and then back to 900mm. Between the 29th storey and the top storey, the range is between 900 and 300mm in relation to the line of the façade.

Capital Gate’s shell comprises a super-strong exo-skeleton called the diagrid, that provides a clear, unobstructed floor plate, using much less steel than a conventional structural frame.

Guinness appointed awards committee found the Capital Gate surpassed the Pisa tower in its slant. However that tower has been deliberately engineered to slant is not able to shadow the glory of the “real” leaning tower.

Vaisakh G.

Why "NO" to BT Brinjal

Let us evaluate WHY we sholud say "NO" to BT Brinjal.

1. Effective non-pesticide pest management and Integrated Pest Management exists and is being practised by farmers.
   The question of internal destruction of pests is dangerous to the health of the consumer. The integrated pest management systems, in combination with good farming practices, are the only healthy solution to good crops. A healthy farm ecosystem is the key to pest management. This includes selection of good seeds, appropriate irrigation system and improving soil quality.
2. The experiences with a few other GM crops released in India and other parts of the world, especially Bt cotton, shows that over a period of time the total pesticide usage in GM crops has gone up due to increased secondary pest attacks and in some cases due to tolerance developed by the target pest. The Nagpur case study of the pest attack on Bt cotton plants shows that Bt does not have a foolproof mechanism to remove pest threat.
3. Controlling pests with single toxic molecules either produced in factory or plant cell is an unscientific way of managing pests. Pests should be managed, not killed.
4. The studies on non-target pests at best were inadequate and inaccurate. The studies have been focused on a limited number of insects and for only a limited period of time.
5. The studies were also done with a surrogate protein and not with the modified Cry1Ac used in Bt brinjal.
6. As Bt brinjal is created to produce the Cry1Ac toxin in every cell, the 'pesticides' have actually moved from exterior to the interior of brinjal, and this cannot be removed by washing as in the case of the usual pesticide at present.
7. The studies on soil microflora were for a very short period. The impact of the break down products of the protein Cry1Ac on soil micro flora has not been conducted.
8. India is a centre of origin and diversity of brinjal which has been cultivated here for over 4000 years. There are about 2000 varieties grown across India.
9. The transgene transfer to local and hybrid varieties of brinjal will effectively destroy our brinjal diversity. As a general rule GM crops should not be cultivated in the center of origin as it could lead to the loss of original varieties by transgenic cross pollination.
10. Inadequacy of tests:No third party or independent tests have been conducted so far on the Bt impact on human health.
11. The longest study has been a 90 day sub-chronic test on a healthy adult rat. This does not address the possible health impact on humans of Bt brinjal as brinjal is a regularly eaten vegetable.
12. Significant chronic toxicity studies including carcinogenicity studies have not been conducted.
13. Brinjal itself has an inherent property of allergenecity which may be enhanced further in the Bt variety.
14. When pesticides were first introduced and promoted, they were said to be harmless to human health. However, tough lessons have been learnt since then about the actual effects of pesticides. Genetic Engineering will have huge and as yet unknown implications for human health
15. Brinjal in India is often eaten lightly cooked. In traditional medicine brinjal is used in its raw form. In its raw form the Cry1Ac toxin in the Bt brinjal is active and extremely dangerous.
16. The human digestive system is mildly acidic only in the stomach, where the food resides briefly before it passes to the duodenum. The medium then changes from mildly acidic to alkaline to aid the working of the digestive enzymes of tryptase, amylase and lipase. The rest of the human alimentary canal remains alkaline till the end. Hence if the Cry1Ac toxin is active in alkaline medium, there will be a high absorption of the toxin into the human system leading to high toxicity in the human body.
17. While India at present lacks a labeling and liability regime, there are also concerns that it will not help even if we have a labeling law in place as only a miniscule quantity of Brinjal or, for that matter, any vegetable is packed and sold.
18. Studies on the accumulation or wash-out time span on this specific endo-toxin in Bt. brinjal
    have not been done. Historically the absorption and accumulation of the endo-toxins can be carcinogenic to humans.
19. The existing assessments have completely overlooked the impact of Bt brinjal on the Indian systems of medicine. Given that brinjal and related plants are used in Ayurveda, Siddha and so on this is a significant lapse. It is not clear, therefore, whether the entry of Bt brinjal could make Indian systems of medicine/practices ineffective or even toxic, with regard to use of brinjal.
20. In Ayurveda around 14 varieties of the brinjal are being used for medicinal preparations. Each one differs in its medicinal properties. Any intrusion in the basic nature will alter the Rasa (Taste), Guna (Property), Veerya (Potency), Vipaka (End Taste) and Prabhava (Synergetic Property) of the drug. These properties are coded for each drug and according to these codes the physicians are able to select a particular drug for a specific ailment. Transgenic changes would alter these properties and create a new plant with unknown coding. While doing agronomic studies Bt brinjal has not been compared with best agricultural practices like non- pesticide management or integrated pest management practices being successfully undertaken in the country.
21. Majority of the farmers in India are small and marginal farmers, so the possibility for maintaining isolation distances is inexistent. There is no guarantee that the prices will actually go down. On the contrary increased input costs could increase the price of Bt brinjal. The Bt cotton example shows that the seed cost increases substantially with GM crops thereby increasing the input costs.
22. Organic farmers would be at risk as there would be no mechanism by which contamination by the transgene could be stopped. This would lead them to lose their certification and markets. This is evident from the examples from what happened in the case of Bt cotton.
23. While Mahyco shared the truncated gene cry1Ac construct they developed with the public sector research institutions, there are conditions in the MoU stopping these institutions from developing their own hybrids or having a free hand in marketing of the OPVs.
24. None of the public sector products would reach the market for another two years as they are yet to complete their trials. By then Mahyco, who have their GM brinjal hybrids ready, would completely dominate the markets. Thus the technology sharing is just a Trojan horse to get their product

These are not my arguments, but those i found in the website of Ministry of Environment and Forest, Government of India (http://moef.nic.in)