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16
History of Mathematics / History of Mathematics
« on: November 08, 2012, 10:29:30 AM »
The area of study known as the history of mathematics is primarily an investigation into the origin of discoveries in mathematics and, to a lesser extent, an investigation into the mathematical methods and notation of the past.

Before the modern age and the worldwide spread of knowledge, written examples of new mathematical developments have come to light only in a few locales. The most ancient mathematical texts available are Plimpton 322 (Babylonian mathematics c. 1900 BC),  the Rhind Mathematical Papyrus (Egyptian mathematics c. 2000-1800 BC), and the Moscow Mathematical Papyrus (Egyptian mathematics c. 1890 BC). All of these texts concern the so-called Pythagorean theorem, which seems to be the most ancient and widespread mathematical development after basic arithmetic and geometry.

The study of mathematics as a subject in its own right begins in the 6th century BC with the Pythagoreans, who coined the term "mathematics" from the ancient Greek μάθημα (mathema), meaning "subject of instruction". Greek mathematics greatly refined the methods (especially through the introduction of deductive reasoning and mathematical rigor in proofs) and expanded the subject matter of mathematics. Chinese mathematics made early contributions, including a place value system. The Hindu-Arabic numeral system and the rules for the use of its operations, in use throughout the world today, likely evolved over the course of the first millennium AD in India and was transmitted to the west via Islamic mathematics. Islamic mathematics, in turn, developed and expanded the mathematics known to these civilizations. Many Greek and Arabic texts on mathematics were then translated into Latin, which led to further development of mathematics in medieval Europe.

From ancient times through the Middle Ages, bursts of mathematical creativity were often followed by centuries of stagnation. Beginning in Renaissance Italy in the 16th century, new mathematical developments, interacting with new scientific discoveries, were made at an increasing pace that continues through the present day.

Mathematics during the Scientific Revolution:

17th century

The 17th century saw an unprecedented explosion of mathematical and scientific ideas across Europe. Galileo observed the moons of Jupiter in orbit about that planet, using a telescope based on a toy imported from Holland. Tycho Brahe had gathered an enormous quantity of mathematical data describing the positions of the planets in the sky. Through his position as Brahe's assistant, Johannes Kepler was first exposed to and seriously interacted with the topic of planetary motion. Kepler's calculations were made simpler by the contemporaneous invention of logarithms by John Napier and Jost Bürgi. Kepler succeeded in formulating mathematical laws of planetary motion. [130] The analytic geometry developed by René Descartes (1596–1650) allowed those orbits to be plotted on a graph, in Cartesian coordinates. Simon Stevin (1585) created the basis for modern decimal notation capable of describing all numbers, whether rational or irrational.

Building on earlier work by many predecessors, Isaac Newton discovered the laws of physics explaining Kepler's Laws, and brought together the concepts now known as infinitesimal calculus. Independently, Gottfried Wilhelm Leibniz developed calculus and much of the calculus notation still in use today. Science and mathematics had become an international endeavor, which would soon spread over the entire world.[131]

In addition to the application of mathematics to the studies of the heavens, applied mathematics began to expand into new areas, with the correspondence of Pierre de Fermat and Blaise Pascal. Pascal and Fermat set the groundwork for the investigations of probability theory and the corresponding rules of combinatorics in their discussions over a game of gambling. Pascal, with his wager, attempted to use the newly developing probability theory to argue for a life devoted to religion, on the grounds that even if the probability of success was small, the rewards were infinite. In some sense, this foreshadowed the development of utility theory in the 18th–19th century.

18th century


The most influential mathematician of the 18th century was arguably Leonhard Euler. His contributions range from founding the study of graph theory with the Seven Bridges of Königsberg problem to standardizing many modern mathematical terms and notations. For example, he named the square root of minus 1 with the symbol i, and he popularized the use of the Greek letter \pi to stand for the ratio of a circle's circumference to its diameter. He made numerous contributions to the study of topology, graph theory, calculus, combinatorics, and complex analysis, as evidenced by the multitude of theorems and notations named for him.

Other important European mathematicians of the 18th century included Joseph Louis Lagrange, who did pioneering work in number theory, algebra, differential calculus, and the calculus of variations, and Laplace who, in the age of Napoleon, did important work on the foundations of celestial mechanics and on statistics.

20th century:

The 20th century saw mathematics become a major profession. Every year, thousands of new Ph.D.s in mathematics are awarded, and jobs are available in both teaching and industry.

In a 1900 speech to the International Congress of Mathematicians, David Hilbert set out a list of 23 unsolved problems in mathematics. These problems, spanning many areas of mathematics, formed a central focus for much of 20th-century mathematics. Today, 10 have been solved, 7 are partially solved, and 2 are still open. The remaining 4 are too loosely formulated to be stated as solved or not.
A map illustrating the Four Color Theorem
Notable historical conjectures were finally proven. In 1976, Wolfgang Haken and Kenneth Appel used a computer to prove the four color theorem. Andrew Wiles, building on the work of others, proved Fermat's Last Theorem in 1995. Paul Cohen and Kurt Gödel proved that the continuum hypothesis is independent of (could neither be proved nor disproved from) the standard axioms of set theory. In 1998 Thomas Callister Hales proved the Kepler conjecture.

Mathematical collaborations of unprecedented size and scope took place. An example is the classification of finite simple groups (also called the "enormous theorem"), whose proof between 1955 and 1983 required 500-odd journal articles by about 100 authors, and filling tens of thousands of pages. A group of French mathematicians, including Jean Dieudonné and André Weil, publishing under the pseudonym "Nicolas Bourbaki", attempted to exposit all of known mathematics as a coherent rigorous whole. The resulting several dozen volumes has had a controversial influence on mathematical education.[132]
Newtonian (red) vs. Einsteinian orbit (blue) of a lone planet orbiting a star, with relativistic precession of apsides

Differential geometry came into its own when Einstein used it in general relativity. Entire new areas of mathematics such as mathematical logic, topology, and John von Neumann's game theory changed the kinds of questions that could be answered by mathematical methods. All kinds of structures were abstracted using axioms and given names like metric spaces, topological spaces etc. As mathematicians do, the concept of an abstract structure was itself abstracted and led to category theory. Grothendieck and Serre recast algebraic geometry using sheaf theory. Large advances were made in the qualitative study of dynamical systems that Poincaré had begun in the 1890s. Measure theory was developed in the late 19th and early 20th centuries. Applications of measures include the Lebesgue integral, Kolmogorov's axiomatisation of probability theory, and ergodic theory. Knot theory greatly expanded. Quantum mechanics led to the development of functional analysis. Other new areas include, Laurent Schwarz's distribution theory, fixed point theory, singularity theory and René Thom's catastrophe theory, model theory, and Mandelbrot's fractals. Lie theory with its Lie groups and Lie algebras became one of the major areas of study.

Non-standard analysis, introduced by Abraham Robinson, rehabillitated the infinitesimal approach to calculus, which had fallen into disrepute in favour of the theory of limits, by extending the field of real numbers to the Hyperreal numbers which include infinitesimal and infinite quantities.

The development and continual improvement of computers, at first mechanical analog machines and then digital electronic machines, allowed industry to deal with larger and larger amounts of data to facilitate mass production and distribution and communication, and new areas of mathematics were developed to deal with this: Alan Turing's computability theory; complexity theory; Claude Shannon's information theory; signal processing; data analysis; optimization and other areas of operations research. In the preceding centuries much mathematical focus was on calculus and continuous functions, but the rise of computing and communication networks led to an increasing importance of discrete concepts and the expansion of combinatorics including graph theory. The speed and data processing abilities of computers also enabled the handling of mathematical problems that were too time-consuming to deal with by pencil and paper calculations, leading to areas such as numerical analysis and symbolic computation. Some of the most important methods and algorithms of the 20th century are: the simplex algorithm, the Fast Fourier Transform, error-correcting codes, the Kalman filter from control theory and the RSA algorithm of public-key cryptography.

At the same time, deep insights were made about the limitations to mathematics. In 1929 and 1930, it was proved the truth or falsity of all statements formulated about the natural numbers plus one of addition and multiplication, was decidable, i.e. could be determined by some algorithm. In 1931, Kurt Gödel found that this was not the case for the natural numbers plus both addition and multiplication; this system, known as Peano arithmetic, was in fact incompletable. (Peano arithmetic is adequate for a good deal of number theory, including the notion of prime number.) A consequence of Gödel's two incompleteness theorems is that in any mathematical system that includes Peano arithmetic (including all of analysis and geometry), truth necessarily outruns proof, i.e. there are true statements that cannot be proved within the system. Hence mathematics cannot be reduced to mathematical logic, and David Hilbert's dream of making all of mathematics complete and consistent needed to be reformulated.
The absolute value of the Gamma function on the complex plane.

One of the more colorful figures in 20th-century mathematics was Srinivasa Aiyangar Ramanujan (1887–1920), an Indian autodidact who conjectured or proved over 3000 theorems, including properties of highly composite numbers, the partition function and its asymptotics, and mock theta functions. He also made major investigations in the areas of gamma functions, modular forms, divergent series, hypergeometric series and prime number theory.

Paul Erdős published more papers than any other mathematician in history, working with hundreds of collaborators. Mathematicians have a game equivalent to the Kevin Bacon Game, which leads to the Erdős number of a mathematician. This describes the "collaborative distance" between a person and Paul Erdős, as measured by joint authorship of mathematical papers.

As in most areas of study, the explosion of knowledge in the scientific age has led to specialization: by the end of the century there were hundreds of specialized areas in mathematics and the Mathematics Subject Classification was dozens of pages long.[133] More and more mathematical journals were published and, by the end of the century, the development of the world wide web led to online publishing.

21st century:

In 2000, the Clay Mathematics Institute announced the seven Millennium Prize Problems, and in 2003 the Poincaré conjecture was solved by Grigori Perelman (who declined to accept an award on this point).

Most mathematical journals now have online versions as well as print versions, and many online-only journals are launched. There is an increasing drive towards open access publishing, first popularized by the arXiv.

Future of mathematics:
Main article: Future of mathematics

There are many observable trends in mathematics, the most notable being that the subject is growing ever larger, computers are ever more important and powerful, the application of mathematics to bioinformatics is rapidly expanding, the volume of data to be analyzed being produced by science and industry, facilitated by computers, is explosively expanding.

17
Natural Science / Introduction to Natural Sciences
« on: November 07, 2012, 03:14:27 PM »
The natural sciences are branches of science that seek to elucidate the rules that govern the natural world by using scientific methods. The term "natural science" is used to distinguish the subject matter from the social sciences, which apply the scientific method to study human behavior and social patterns; the humanities, which use a critical or analytical approach to study the human condition; and the formal sciences such as mathematics and logic, which use an a priori, as opposed to factual methodology to study formal systems.

There are five branches of natural science: astronomy, biology, chemistry, the Earth sciences and physics. This distinguishes sciences that cover inquiry into the world of nature from human sciences such as anthropology, sociology and linguistics, and from formal sciences such as mathematics and logic. Despite their differences, these sciences sometimes overlap; the social sciences and biology both study human beings as organisms, for example, and mathematics is used regularly in all the natural sciences.

The natural sciences are among the basic sciences, or scientific fields where study is motivated purely by curiosity. They also form the basis for applied sciences, however, which find real-world, practical applications for concepts and methods developed in basic science. In academic contexts, the natural and applied sciences are distinguished from the social sciences on the one hand, and the humanities on the other. Not all institutions and scientists are in agreement, however, about the classification of sciences and other academic disciplines.

Alongside its traditional usage, natural science may encompass natural history, which emerged in the 16th century and focused on the description and classification of plants, animals, minerals and other natural objects. Today, natural history refers to observational descriptions of the natural world aimed at popular audiences rather than an academic ones. The natural sciences are sometimes referred to colloquially as hard science, or fields seen as relying on experimental, quantifiable data or the scientific method and focusing on accuracy and objectivity. These usually include physics, chemistry and biology.  By contrast, soft science is used a as a pejorative term to describe fields more reliant on qualitative research, including the social sciences.

Aristotelian natural philosophy:

Later Socratic and Platonic thought focused on ethics, morals and art and did not attempt an investigation of the physical world; Plato criticized pre-Socratic thinkers as materialists and anti-religionists. Aristotle, however, a student of Plato who lived from 384 to 322 B.C., paid closer attention to the natural world in his philosophy. In his History of Animals, he described the inner workings of 110 species, including the stingray, catfish and bee. He investigated chick embryos by breaking open eggs and observing them at various stages of development. Aristotle's works were influential through the 19th century, and he is considered by some scholars to be the father of biology. He also presented philosophies about physics, nature and astronomy using inductive reasoning in his works Physics and Meteorology.


Plato (left) and Aristotle in a 1509 painting by Raphael. Plato rejected inquiry into natural philosophy as against religion, while his student, Aristotle, created a body of work on the natural world that influenced generations of scholars.

Aristotle's works on natural philosophy continued to be translated and studied amid the rise of the Byzantine Empire and Islam in the Middle East. A revival in mathematics and science took place during the time of the Abbasid Caliphate from the ninth century onward, when Muslim scholars expanded upon Greek and Indian natural philosophy.  The words alcohol, algebra and zenith all have Arabic roots.

18
Science Discussion Forum / Protect Your Skin From Summer Sun
« on: May 22, 2012, 09:52:39 AM »
Skin Damage from the Sun can Cause Skin Cancer: Prevent damage from the sun

Summer is certainly a "fun" time of the year but it goes without saying that self-protection is also of extreme significance.Getting a skin tan is "in" these days and is certainly considered as the "cool" and fashionable thing to do in many countries across the world. Thanks to this fashion, now millions of people hit the beaches during summer in sometimes even 40 degree celcius temperature or higher and lie down on the beaches without any sun protection to sun bathe and "soak up the sun".


We know that sun causes a substance in our skin to produce a certain kind of Vitamin D (sometimes also referred to as the :Sunshine Vitamin). Therefore it is certainly essential to get at least some amount of sunlight during the day. However, the fact we conveniently ignore is that due to thinning of the Earth's ozone layer, harmful Ultraviolet (UV) rays of the sun can not only cause sun burn and premature wrinkling of the skin (along with the much desired sun tan) but also the dreadful "skin cancer".

Skin cancer also known as malenoma, can be malignant (which can spread can cause death)as well as benign (which usually does not spread in the body and may or may not be deadly). Melignant Skin cancer like other fatal cancers can lead to death if detected at the last stages of the disease.
Residents of some regions of the world, where the Earth's Ozone layer is thinner than others and they experience extreme UV index during the summer season, are at a higher risk of getting skin cancer. In such regions and countries (including Australia), special government campaigns are run to spread awareness about skin cancer among people and educate people to protect themselves and their children. Warnings are issued in very hot summer days with extreme UV index on the TV and internet so people should not stay out doors in direct sunlight for long periods of time.

Considering these alarming situations in some regions of the world, some people can get very worried about getting their skin sun-damaged and how to go about with the protective measures. However, it may surprise you that it is easier to prevent skin damage from the sun than we might have anticipated. Here are a few simple ways to prevent "skin damage" from the sun.

Use Hats and Loose clothing

The damaging UV rays of the sun can not only directly damage the exposed skin but also our hair. Over exposure to extreme heat (very high temperatures during summer) may also cause:

    Heat Stroke and
    Sun Stroke
These conditions can further aggravate conditions if the patient also has sun burn. If we wear a hat and cover most parts of the body with loose clothing we can prevent sunburn and prevent our body from over-heating. Bthing suits for the beach are no harm but if our body is covered sun exposure can be reduced and sun protection enhanced. Ladies who like the new long summer dresses can just love these dresses for one more reason: they will protect their skin from sun damage. Similarly men can wear long pants of light material and wear hats with broad brims to prevent sun damage especially if they have to work for long hours in the sun for long hours (as result of their job, e.g. construction workers).

Protect your eyes and skin surrounding the eyes with Sun-glasses

 Eyes are a very vulnerable part of our bodies. Sun light directly falling on them and especially the high index UV rays can cause even blindness from a very high and prolonged exposure. Remember when "reflected" UV rays fall on to the skin and eyes they can cause the same amount of damage or even greater. UV rays can get reflected from shiny surfaces, sand, glass and snow (in winters).

The skin around the eyes is more sensitive than any other skin and can get easily wrinkled and damaged. It is very important to protect it. One good way is to use "sun glasses" and protect both eyes and the eyes around the skin. Broad brimmed glassed with dark glasses which cover eyes and area around the yes completely are highly recommended. The glasses should be approved and provide maximum protection from the sun's rays, (high UV index).

19
Science Discussion Forum / History of Natural Science
« on: April 26, 2012, 03:09:56 PM »
In ancient and medieval times, the objective study of nature was known as natural philosophy. In late medieval and early modern times, a philosophical interpretation of nature was gradually replaced by a scientific approach using inductive methodology. The work of Sir Francis Bacon popularized this approach, thereby helping to forge the scientific revolution.

Philip Morris Hauser wrote:

    The history of the physical sciences is replete with episode after episode in which the discoveries of science, subversive as they were because they undermined existing knowledge, had a hard time achieving acceptability and respectability. Galileo was forced to recant; Bruno was burned at the stake; and so forth.

By the 19th century, the study of science had come into the purview of professionals and institutions. In so doing, it gradually acquired the more modern name of natural science. The term scientist was coined by William Whewell in an 1834 review of Mary Somerville's On the Connexion of the Sciences. But the word did not enter general use until nearly the end of the same century.

Today, natural sciences are more commonly divided into life sciences, such as botany and zoology; and physical sciences, which include physics, chemistry, geology and astronomy.

The natural sciences are branches of science that seek to elucidate the rules that govern the natural world by using scientific methods. The term "natural science" is used to distinguish the subject matter from the social sciences, which apply the scientific method to study human behavior and social patterns; the humanities, which use a critical or analytical approach to study the human condition; and the formal sciences such as mathematics and logic, which use an a priori, as opposed to factual methodology to study formal systems.


The natural sciences seek to understand how the world and universe around us works. There are five major branches: Chemistry (center), astronomy, earth science, physics, and biology (clockwise from top-left).

Natural sciences are the basis for applied sciences. Together, the natural and applied sciences are distinguished from the social sciences on the one hand, and the humanities on the other. Though mathematics, statistics, and computer science are not considered natural sciences, for instance, they provide many tools and frameworks used within the natural sciences.

Alongside this traditional usage, the phrase natural sciences is also sometimes used more narrowly to refer to natural history. In this sense "natural sciences" may refer to the biology and perhaps also the earth sciences, as distinguished from the physical sciences, including astronomy, physics, and chemistry.

Within the natural sciences, the term hard science is sometimes used to describe those subfields which some people view as relying on experimental, quantifiable data or the scientific method and focus on accuracy and objectivity. These usually include physics, chemistry and biology. By contrast, soft science is often used to describe the scientific fields that are more reliant on qualitative research, including the social sciences.



20
Your health is your life, and your wealth represents the fruits of your labor.  I assume you don’t want to be wasteful with either of them.  Here’s how to save both at the same time:

So many people spend their health gaining wealth,
and then have to spend their wealth to regain their health.
- A.J. Reb Materi

1. Reduce Your Consumption of Drugs – That includes alcohol, cigarettes, over the counter, prescription and otherwise.  Drugs are a huge financial drain, and in most cases, unhealthy for the human body.  A significant portion of the global population abuses the crap out of them on a daily basis, legally and illegally.

2. Learn to Cook and Prepare Healthy Food – People who eat every meal out tend to have lighter wallets and heavier rear ends.  With the exception of pricey, upscale dining establishments, you’ll find that most restaurants use lower-grade ingredients and employ sketchy sanitary practices that fall well below the standards you embrace in your own kitchen.  So when you eat out, you’re either spending more cash or eating low-grade product.  Regardless, you lose.  The ability to cook and prepare healthy meals is a vital skill everyone should know how to do.

3. Brown Bag the Leftovers for Lunch – Always cook enough at dinnertime so you can enjoy lunchtime leftovers the following day.  Leftovers are faster, easier, cheaper and healthier than anything you’ll find at the local fast food eatery.

4. Avoid Overpriced, Unproven Supplements – Most people assume that FDA approved nutritional supplements are proven products.  Wrong!  Do you really think the FDA has enough resources to precisely verify every new dietary supplement proposed to hit the market?  I assure you, they don’t and there is no feasible way they ever will.  Remember, the FDA concentrates its efforts on drugs, not supplements.  Under the active Dietary Supplement and Health Education Act, producers of dietary supplements do not have to verify that their product is effective, safe or at all healthy prior to placing it on store shelves.  Sometimes someone has to become dreadfully ill from a dietary supplement before it even becomes a “blip” on the FDA’s radar.

5. Drink Filtered Tap Water – I’ve said it before, people go to work and trade priceless hours of their lives for dollars and then waste the dollars buying something that’s already free.  A Brita water filter is an inexpensive investment that makes free tap water as healthy and pure as the bottled water for sale at the local supermarket.  Since a penny saved is a penny earned, you’ll be making money every time you take a sip.  Also, substituting beverages like soda for filtered tap water is another healthy way to save.

6. Stop Driving Like a Maniac – The faster you accelerate your vehicle, the more gas you will burn.  People who are heavy on the pedal use up to 37% more gas during every mile of city driving.  At $4 a gallon, that’s a lot of wasted money.  Also, the faster you drive, the less time you have to react to hazardous road conditions.  Bottom line: Drive responsibly at or below the speed limit.

7. Brew Your Own Coffee – Is coffee perfectly healthy for you?  It’s hard to say for sure.  There is a good deal of medical research to validate both sides of the argument (see here and here).  However, one point remains certain: millions of people across the globe drink coffee every single morning.  Many of them wasting significant amounts of money on fatty, sugar and cream packed coffee beverages from Starbucks-style coffeehouses.  So the real question is: How do you make the coffee drinking habit healthier and less expensive?  The answer is simple.  Brew your own coffee.  If you like, add a dash of low fat milk and a single packet of sugar.  It’s quick, fairly healthy and way cheaper than Starbucks.  We have a Cuisinart Two-to-Go Coffeemaker and absolutely love it.

8. Wear Helmets and Protective Body Gear – How many motorcyclists, bicyclists, skateboarders, etc. do see foolishly blazing around without wearing any form of protective body gear?  It’s your life.  A quality bicycle helmet will cost you $40 and 2 seconds of your time to put it on before you ride.  If you don’t wear one and end up crashing and cracking your head open, it could cost you thousands of dollars in medical bills and take months, if not years, for your body to fully recover.

9. Stay In and Hang Out – Your home is your haven.  It’s the safest, most comfortable environment to relax and socialize in.  It also happens to be a far cheaper alternative to the local bars, pubs and clubs.  You can save money on gas and entertainment costs while avoiding a lungful of secondhand smoke.  So login to eBay, sell some stuff you don’t use, buy yourself a Wii and invite over a few of your favorite people.  Don’t forget to crank-up the tunes.  ;-)

10. Buy Healthy, Generic Brand Food – When it comes to the bare essentials on your grocery list, generic brands can provide the same food quality at a significantly reduced cost.  U.S. food manufacturers are forced to follow a set of standards which basically guarantees the quality of the food they produce.  Many large-scale grocery chains purchase name brand products directly from the manufacturer and simply slap their own generic brand label on the packaging.  You should always compare the generic brand’s list of ingredients to a name brand product just to make sure everything matches up.

11. Eat Fresh Produce that is In Season – Based on abundant crops and excessive supplies, produce that is in season is fresher, more nutritious and cheaper than produce that is out of season.  Take a quick look around the produce isle.  The fresh, seasonal produce will be piled high and priced low.  The fluctuations in price can be quite significant.  For instance, an ear of corn will cost about 10 cents in the summer and nearly a dollar in the wintertime.

12. Play Sports with Your Friends – Racquetball, tennis, kickball, basketball… Honestly, it doesn’t matter what you play, so long as it’s an active sport that you enjoy.  When you play sports with your friends you’re basically hitting 3 birds with 1 stone.  You’re getting healthy exercise and quality social time without spending a dime.

13. Walk a Mile Everyday – Most medical professionals agree that walking is the healthiest form of exercise.  Studies have shown that overweight twenty-somethings spend significantly more on medical bills over the course of their lives.  Adding a 1 mile walk into your daily routine is a quick way to get some exercise and lose a couple pounds without spending money on a gym membership.  My colleagues and I walk a mile everyday after lunch.  We walk, we talk and we come back to the office feeling refreshed.

14. Do Some Weekly Meal Planning – A little meal planning can reduce the cost of preparing a meal by preventing you from overspending on ingredients you don’t need.  It’s also much less stressful to prepare a meal without running around at the last second trying to figure out what ingredients you have so you know what you can cook.  This scenario is exactly why most people give up and waste their money at unhealthy fast food restaurants.

15. Buy in Bulk, Cook in Bulk – Join a discount shopping club like Costco.  Even though there’s a membership fee, discount clubs can be extremely cost-effective if you purchase the majority of your groceries in bulk.  Buying and cooking food in bulk is a great way to save money and maintain a healthy diet.  If you cook a week’s worth of healthy food in bulk, you’ll probably end up eating healthier all week long than you would have otherwise.  Angel and I usually cook in bulk for the entire week on Sunday evenings.  Having our food already prepared when we return home from work is a huge time saver and stress reducer on busy week nights.

21
Sports Zone / Dept. of TE and T-20 Inter Department Cricket Tournament
« on: February 20, 2012, 03:57:10 PM »
Congratulations!!!!!!!!!!!..................TE Department as well as all members of the team

we are number one. Carry on...............

again thanks and best of luck.

What your feelings about TE and T-20  Inter Department Cricket Tournament?  

      

22
Sports Zone / Bangladesh Premier League (BPL)
« on: February 15, 2012, 12:42:39 PM »
Our main goal should be improve our cricket so that we can perform better in international match by gathering more experience from others.............

What about your idea about BPL?


Chris Gayle scored 116 off 61 balls but Barisal Burners still lost to Dhaka Gladiators © BPL T20


plz visit  if wish
http://www.espncricinfo.com/bangladesh-premier-league-2012/content/story/552699.html

23
Congratulations................!!!! Textile Engineering Department to win the 1st prize for stall representation in 10th foundation day of DIU. Thanks all the members of the team

carry on.................with speed for future.    


plz share your feelings regarding stall and stage performance of TE dept. in 10th foundation day. 

24
Hinduism / Bani Archana (Saraswati Puja) 2012
« on: January 16, 2012, 01:43:14 PM »
First time, we are going to celebrate Saraswati puja-2012 with collaboration of all Teachers, Student and Officials in our Daffodil International Campus (DIIT campus) on January28, 2012.


All of you are invited in this program.
 To make this traditional practice a success, we are soliciting your wholehearted cooperation.    

25
Common Forum / Traffic Jam in Dhaka city
« on: December 12, 2011, 02:16:20 PM »
Over the last few years the transportation problem of Dhaka City has visibly been deteriorating steadily. Citizens constantly complain about the unbearable twin problems of traffic jam and air pollution. Democracywatch decided to address this problem through an opinion poll covering around eight hundred households randomly selected from several purposively selected neighbourhoods of the city,  representatives of middle and lower income areas.
The questions asked focused mainly on three issues: (a) the nature of the problem as perceived by the surveyed residents, (b) their understanding about the causes of these problems and (c) their recommendations on solutions to these perceived problems.
Some preliminary results from this survey were presented at a workshop, which was participated by persons associated with the formulation and implementation of traffic policies, rules and programmes. This Draft Final Report benefits from valuable discussion and comments received at the workshop.
The methodology of this survey is explained below in brief. It is easy to see that the study extended beyond a standard opinion poll and entered the arena of investigative research in seeking some
explanations to perceptions as well as behaviour.
The findings are presented mainly in the form of self-explanatory tables with some introductory highlights and conclusions.
A further extension of the survey is currently being completed to cover the very poor and the rich categories of residents as was recommended by several participants at the workshop mentioned earlier.

B. Methodology:

During the round of the opinion poll the main focus was on the middle and lower income population of Dhaka city. Therefore, the sample was drawn from 30 purposively selected neighbourhoods which are generally recognised as middle and lower income areas. In each of these areas a systematic random sample of about 26 households were selected, giving a total sample of 775 households. In the event of any household’s refusal to give interview which happened on average in one in four cases, the nearest household willing to be interviewed was chosen. Usually the household head responded. In case of his absence any other responsible adult capable of responding to the questions was interviewed. Interviews were conducted on the basis of a pre-tested questionnaire. Each interview took about 20 minutes. Fourteen investigators were engaged. The reference period for the survey was 21-27 October, 2000. Data was edited, coded and computerised. Analysis was mostly done electronically by using FoxPro and SPSS. Some tables were done manually.

C. Selected Findings
:
I. Perceptions on major problems
•   Altogether 37 problems were mentioned. They were given a score on a scale of 1-5 to indicate their perceived seriousness. Each of these problems was then ranked according to the total score given to it by the analytical group under consideration.
•   Not surprisingly, traffic jam topped the list, followed by hijacking/terrorism as no. 2, load shedding as no. 3, environmental pollution as no. 4 and water crisis as no. 5.
•   Surprisingly, hartals were way down among the bottom 5 (at no. 33), reflecting possibly both a shortness of public memory as well as a lack of concern or an acquired immunity at the mass level in respect of hartals.


•   Changes in public perception about the seriousness of problems in civic life was also evidenced by the placement of load shedding at no. 3, which would undoubtedly have been put as the no. 1 problem about 2 years ago.
•   Except for problems no. 1 and no. 2 there was variation in the rank order of the perceived problems based on income, occupation, education and gender. For example, environmental pollution was given more importance by the richer people compared to load shedding. Likewise, unemployment was more of a problem for the poorer categories.
•   Interestingly, poor drainage was not mentioned in the list of 5 most important problems in the city. Clearly, for all the sampled respondents, there were far too many other problems to enter the list of 5.


II. Causes of traffic jam
•   Narrow roads, broken roads and unplanned repairs appeared as the 3 main causes of traffic jam. This again is the result of asking the respondents to name only 3 main causes.
•   When asked about the contribution of different road users to the traffic jam problem, the rickshaw wallahs were pointed out as a major culprit: 66 per cent thought they made very high contribution, while another 5 per cent thought they made moderate contribution.
•   The truck drivers were next in line with about 50 per cent considering their contribution as moderate to very high.
•   There were no significant variations in respect of the above findings between genders, incomes and occupations.


III. Recommended measures for solving traffic jams
•   There were more recommendations on the software (i.e. legal framework, planning, management, etc) than on the hardware side (i.e. brick and mortar stuff).
•   The single most recommended measure was one way roads (28 per cent). Interestingly, the richer and the professional households were less vocal about it, while the labourers did not mention it at all. The demand came mainly from the businessmen and lower income households.
•   The next most recommended (22 per cent) measure was to improve and enforce the traffic law. If one adds to that the recommendation of establishment and enforcement of sound parking rules (11 per cent), legal reform and enforcement emerges as the most recommended (33 per cent) measure.
•   There was broad unanimity in this regards between the genders, incomes and most occupations except the professionals for whom flyovers were the second most mentioned remedy.

26
Science Discussion Forum / Traffic Jam
« on: December 12, 2011, 11:24:00 AM »
Traffic Jam is a condition on road networks that occurs as use increases, and is characterized by slower speeds, longer trip times, and increased vehicular queueing. The most common example is the physical use of roads by vehicles. When traffic demand is great enough that the interaction between vehicles slows the speed of the traffic stream, this results in some congestion. As demand approaches the capacity of a road (or of the intersections along the road), extreme traffic congestion sets in. When vehicles are fully stopped for periods of time, this is colloquially known as a traffic jam or traffic snarl-up.


Traffic congestion occurs when a volume of traffic or modal split generates demand for space greater than the available road capacity; this point is commonly termed saturation. There are a number of specific circumstances which cause or aggravate congestion; most of them reduce the capacity of a road at a given point or over a certain length, or increase the number of vehicles required for a given volume of people or goods. About half of U.S. traffic congestion is recurring, and is attributed to sheer weight of traffic; most of the rest is attributed to traffic incidents, road work and weather events.[2]

Causes of Traffic Jam:

Traffic research still cannot fully predict under which conditions a "traffic jam" (as opposed to heavy, but smoothly flowing traffic) may suddenly occur. It has been found that individual incidents (such as accidents or even a single car braking heavily in a previously smooth flow) may cause ripple effects (a cascading failure) which then spread out and create a sustained traffic jam when, otherwise, normal flow might have continued for some time longer.[3]



Mathematical theories:
Some traffic engineers have attempted to apply the rules of fluid dynamics to traffic flow, likening it to the flow of a fluid in a pipe. Congestion simulations and real-time observations have shown that in heavy but free flowing traffic, jams can arise spontaneously, triggered by minor events ("butterfly effects"), such as an abrupt steering maneuver by a single motorist. Traffic scientists liken such a situation to the sudden freezing of supercooled fluid.[4] However, unlike a fluid, traffic flow is often affected by signals or other events at junctions that periodically affect the smooth flow of traffic. Alternative mathematical theories exist, such as Boris Kerner's three-phase traffic theory (see also spatiotemporal reconstruction of traffic congestion).

Because of the poor correlation of theoretical models to actual observed traffic flows, transportation planners and highway engineers attempt to forecast traffic flow using empirical models. Their working traffic models typically use a combination of macro-, micro- and mesoscopic features, and may add matrix entropy effects, by "platooning" groups of vehicles and by randomising the flow patterns within individual segments of the network. These models are then typically calibrated by measuring actual traffic flows on the links in the network, and the baseline flows are adjusted accordingly.

It is now claimed that equations can predict these in detail:

    Phantom jams can form when there is a heavy volume of cars on the road. In that high density of traffic, small disturbances (a driver hitting the brake too hard, or getting too close to another car) can quickly become amplified into a full-blown, self-sustaining traffic jam...

    A team of MIT mathematicians has developed a model that describes how and under what conditions such jams form, which could help road designers minimize the odds of their formation. The researchers reported their findings May 26 in the online edition of Physical Review E.

    Key to the new study is the realization that the mathematics of such jams, which the researchers call 'jamitons,' are strikingly similar to the equations that describe detonation waves produced by explosions, says Aslan Kasimov, lecturer in MIT's Department of Mathematics. That discovery enabled the team to solve traffic jam equations that were first theorized in the 1950s.[5]

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27
Textile science, events, trade and issues / Textile Fashion
« on: December 05, 2011, 12:37:29 PM »

Patricia Field has always done things her way. With a career spanning 45 years and counting, the designer, stylist and boutique owner built her reputation by creating her own blueprint. “If you asked me who I looked up to from the beginning of my career, I would say no one,” Field said. “I didn’t see fashion that way. I felt fashion.” On the other hand, Field has clearly inspired others in the industry. “As a designer, everyone loves her because she does what designers dream of doing: putting together eccentric pieces,” said designer Christian Siriano.

 â€œAny designer would love to have Patricia pull for one of their projects because that means she thinks it’s interesting, creative, new and special.” George Malkemus, president of Manolo Blahnik USA, said Field’s ability to stay ahead of trends puts her in a unique class. “She always has an extraordinary take on what’s happening on the street before anyone else in fashion,” he said. “She embraces young ideas and young people in a way that very few people in fashion do.”




28
Science Discussion Forum / Walking for Good Health
« on: November 27, 2011, 10:59:28 AM »
Walking can improve health and fitness. Walking can help you lose body fat and maintain a healthy weight, improve your fitness and reduce your risk of developing conditions such as heart disease, type 2 diabetes, osteoporosis and some cancers. To get the health benefits, try to walk for at least 30 minutes as briskly as you can most days of the week.


Benefits of walking

You carry your own body weight when you walk. This is sometimes called ‘weight bearing’ exercise. Some of the benefits include:

    Increased cardiovascular and pulmonary (heart and lung) fitness
    Reduced risk of heart disease and stroke
    Improved management of conditions such as hypertension (high blood pressure), high cholesterol, joint     and muscular pain or stiffness, and diabetes
    Stronger bones and improved balance
    Increased muscle strength and endurance
    Reduced body fat.



Why Walking is Necessary for Good Health – Even If You Are Extremely Fit and Lean:

I use to think that walking was just for people who weren't fit enough to do any "real" exercise. I figured that any activity that 99% of the population can easily do, just can't be tough enough to make a real difference in health. Walking just doesn't seem to challenge the body like "true" exercise (intervals, circuits, HIIT). I am first to admit that I have been wrong when it comes to this line of thinking. Not only do I admit my thinking has been wrong, I'm immediately going to do my best to walk daily. Some recent studies have proven how valuable walking is to long-term health.
[A picture of a young couple walking down a path near the River Thames in London. Walking can be a blast if you are in a scenic place with lots to see. I need to get to London and walk around to look for great pubs. Kind of a walking and beer sampling tour.]

29
Science Discussion Forum / What we have to do During an Earthquake?
« on: November 23, 2011, 03:19:32 PM »
Drop, Cover, and Hold On:

Trying to move during shaking puts you at risk: Earthquakes occur without any warning and may be so violent that you cannot run or crawl; you therefore will most likely be knocked to the ground where you happen to be. So it is best to drop before the earthquake drops you, and find nearby shelter or use your arms and hands to protect your head and neck. "Drop, Cover, and Hold On" gives you the best overall chance of quickly protecting yourself during an earthquake... even during quakes that cause furniture to move about rooms, and even in buildings that might ultimately collapse.

The greatest danger is from falling and flying objects: Studies of injuries and deaths caused by earthquakes over the last several decades show that you are much more likely to be injured by falling or flying objects (TVs, lamps, glass, bookcases, etc.) than to die in a collapsed building. "Drop, Cover, and Hold On" (as described above) will protect you from most of these injuries. If there is no furniture nearby, you can still reduce the chance of injury from falling objects by getting down next to an interior wall and covering your head and neck with your arms (exterior walls are more likely to collapse and have windows that may break). If you are in bed, the best thing to do is to stay there and cover your head with a pillow. Studies of injuries in earthquakes show that people who moved from their beds would not have been injured if they had remained in bed.
You can also reduce your chance of injury or damage to your belongings by securing them in the first place. Secure top heavy furniture to walls with flexible straps. Use earthquake putty or velcro fasteners for objects on tables, shelves, or other furniture. Install safety latches on cabinets to keep them closed. Instructions for how to "secure your space" are at

WHAT RESCUERS AND EXPERTS *DO NOT* RECOMMEND YOU DO DURING AN EARTHQUAKE
:
Based on years of research about how people are injured or killed during earthquakes, and the experiences of U.S. and international search and rescue teams, these three actions are not recommended to protect yourself during earthquakes:

DO NOT run outside or to other rooms during shaking: The area near the exterior walls of a building is the most dangerous place to be. Windows, facades and architectural details are often the first parts of the building to collapse. To stay away from this danger zone, stay inside if you are inside and outside if you are outside. Also, shaking can be so strong that you will not be able to move far without falling down, and objects may fall or be thrown at you that you do not expect. Injuries can be avoided if you drop to the ground before the earthquake drops you.

DO NOT stand in a doorway: An enduring earthquake image of California is a collapsed adobe home with the door frame as the only standing part. From this came our belief that a doorway is the safest place to be during an earthquake. True- if you live in an old, unreinforced adobe house or some older woodframe houses. In modern houses, doorways are no stronger than any other part of the house, and the doorway does not protect you from the most likely source of injury- falling or flying objects. You also may not be able to brace yourself in the door during strong shaking. You are safer under a table.

30
Science Discussion Forum / Transportation Planning
« on: November 03, 2011, 03:32:53 PM »
Nowadays, Transportation problem is one of the major problem in our daily life. As transportation planners and metropolitan planning organizations (MPOs) evaluate current system conditions and alternate future scenarios to make informed decisions on allocating resources, they must balance funding realities with mobility needs; public expectations; and community, legislative, and environmental considerations. Transportation asset management (TAM) provides a valuable tool to maximize system performance, improve customer satisfaction, and minimize life-cycle costs.

What Is Transportation Asset Management?

From increased vehicle miles traveled, growing population, and greater congestion to aging infrastructure and escalating operating costs, today's challenging circumstances put demands greater than ever on transportation networks. The goal of a TAM program is to minimize the life-cycle costs for managing and maintaining transportation assets, including roads, bridges, tunnels, rails, and roadside features. As defined by the American Association of State Highway and Transportation Officials' Subcommittee on Asset Management, "TAM is a strategic and systematic process of operating, maintaining, upgrading, and expanding physical assets effectively through their life cycle. It focuses on business and engineering practices for resource allocation and utilization, with the objective of better decisionmaking based upon quality information and well defined objectives." Through the use of management systems, engineering and economic analysis, and other tools, MPOs and transportation agencies can more comprehensively view the big picture and evaluate collected data before making decisions as to how specific resources should be deployed. TAM principles and techniques should be applied throughout the planning process, from initial goal setting and long-range planning to development of a Transportation Improvement Program and Statewide Transportation Improvement Program and then through to operations, preservation, and maintenance.

What Is the Role of an MPO in Asset Management?

MPOs should ensure that the transportation network is managed to meet both current and future demands and that expenditures are optimal. TAM principles and techniques are valuable tools that can be applied by an MPO and result in more effective decisionmaking. The MPO role in a successful TAM program includes defining performance measures for assets through public involvement, serving as a repository for asset data, and promoting standard data collection and technology applications. MPOs can also educate the public and decisionmakers and work cooperatively with stakeholders across transportation modes.

we will discuss later how can we apply the plan

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