Urbanization Debate:Is sub-Saharan Africa becoming urbanized?

Posted on April 3, 2012 by Rashid Faridi

Dear Readers

While Researching found this very interesting debate . reproducing it with relevant links and credits.See , Think and give inputs.

Research on urban growth has traditionally focused on the Western metropolis, which was shaped by the massive industrialization, modernization, and migration patterns of the nineteenth and twentieth centuries.  In recent years, scholars have started to examine the growth patterns of cities in other regions, such as sub-Saharan Africa, and to question the universality of the Western model of urban development. While earlier data had led many scholars to concludethat cities in that region are growing at an unprecedented rate, new research has challenged the notion that Africa is fast becoming an urban continent.

Rapid growth

In Planet of Slums, urban theorist Mike Davis reported that according to Organization for Economic Co-Operation and Development (OECD) estimates, by 2020 the Gulf of Guinea will be home to three hundred cities, each with a population greater than 100,000 people. Historians Francesca Locatelli and Paul Nugent attributed the growth of sub-Saharan urban areas to the migration of rural residents to cities as well as to higher birth rates in urban areas. Using data originally contained in the 2002 UN publication The World Urbanization Prospects, together with data provided by the World Bank, demographer Barney Cohen projected that fifty-three percent of the sub-Saharan African population may live in urban areas by 2030, a dramatic increase from the first decade of the twenty-first century, when only thirty-eight percent lived in cities.

Slow development

Geographer Deborah Potts questioned these urban growth rates after analyzing UN-HABITAT data on cities in Malawi. With these data, Potts found just a one percent increase in urbanization between 1998 and 2010. Potts suggested that predictions of rapid growth made by other scholars did not adequately reflect the fact that in the 1970s, after several decades of rapid growth, the region entered a period of significant economic hardship that continues to the present day. As a result, rural residents have had little incentive to relocate to larger cities for work.

Resource allocation

As Potts argued, revisiting previous population estimates and growth models is necessary for the accurate allocation of financial and material resources. Equating population growth with urbanization can have negative consequences, she cautions, since the needs created by slow urban growth through increased birth rates are different from the results of projected rapid growth through migration. Understanding the exact model of urban growth at play in the sub-Saharan region is crucial, Potts argues, for politicians and development agencies that may adapt public policy in ways that would further encourage migration to cities.

Sources:Urban Portal

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Dark Energy triggered expansion of Universe six billion years ago:A 3D Map by Astronomers

Posted on April 1, 2012 by Rashid Faridi

What is Dark Energy?

More is unknown than is known. We know how much dark energy there is because we know how it affects the Universe’s expansion. Other than that, it is a complete mystery. But it is an important mystery. It turns out that roughly 70% of the Universe is dark energy. Dark matter makes up about 25%. The rest – everything on Earth, everything ever observed with all of our instruments, all normal matter – adds up to less than 5% of the Universe. Come to think of it, maybe it shouldn’t be called “normal” matter at all, since it is such a small fraction of the Universe.

 Researchers have come up with a 3D map of the sky, which facilitates scientists to look into the time six billion years ago when dark energy became a dominant influence on the Universe’s expansion.

Universe Dark Energy-1 Expanding Universe This diagram reveals changes in the rate of expansion since the universe's birth 15 billion years ago. The more shallow the curve, the faster the rate of expansion. The curve changes noticeably about 7.5 billion years ago, when objects in the universe began flying apart as a faster rate. Astronomers theorize that the faster expansion rate is due to a mysterious, dark force that is pulling galaxies apart. NASA/STSci/Ann Feild

Using the new data, astronomers have been able to measure the exact distance to over a quarter of a million galaxies to gain new understanding of the key period in cosmic history. The discovery that everything in the cosmos is moving apart at a faster and faster rate was one of the major breakthroughs of the 20th Century, and the BOSS survey is a step to examine this phenomenon.The quality of the BOSS map is phenomenal and is a  big step forward on all previous such surveys.
It provides details on the position of galaxies out to some six billion light-years from Earth and gives those measurements to within 1.7 percent of their expected true value.
BOSS uses two techniques to understand the Universe’s acceleration, the first one of them is baryon acoustic oscillations.

These oscillations  are pressure-driven waves that passed through the very early Universe and which were imprinted on the distribution of matter once conditions had cooled below a certain point.
The other technique involves “redshift space distortions”. These describe the component in the velocity of galaxies that stems from the growth of structure in the Universe. The team can see if neighbouring galaxies are clustering in the way that would be expected from the action of gravity.
The BOSS project, which acquires all its data using the 2.5m Sloan telescope at Apache Point Observatory in New Mexico, is only a third complete and will continue to map the 3D positions of galaxies.

Lets see what the future holds for us.

Links and Sources:

Indiatimes

NASA

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Posted on April 1, 2012 by Rashid Faridi

sharonstjoan's avatarEchoes in the Mist

Sometime around 1968, in the south of France, I remember looking up a hill as someone pointed out to me the remains of a Roman aqueduct, still there after 2,000 years – a high wall with arched openings and a stone channel on the top where water used to run.  The Roman system of aqueducts carried water for irrigation and drinking across much of Europe, just as the Roman roads created a transportation web.  Many modern expressways in Europe follow these same ancient paved highways, built by the Roman legionnaires.

What is not so well known is that the Romans did not themselves invent either aqueducts or the system of paved roads.  It was actually the genius of the Etruscans that developed these and a number of other technical wonders.  Etruscans had a high degree of technical knowledge.  They developed the intricacies of water and sewage management, plumbing, irrigation, and…

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Good News:End of the Earth Postponed

Posted on March 31, 2012 by Rashid Faridi
an image of mayan calendar on cosumel island' ...

an image of mayan calendar on cosumel island' Mexico (Photo credit: Wikipedia)

It’s a good news/bad news situation for believers in the 2012 Mayan apocalypse. The good news is that the Mayan “Long Count” calendar may not end on Dec. 21, 2012 (and, by extension, the world may not end along with it). The bad news for prophecy believers? If the calendar doesn’t end in December 2012, no one knows when it actually will — or if it has already.

A chapter in the new textbook “Calendars and Years II: Astronomy and Time in the Ancient and Medieval World” (Oxbow Books, 2010), argues that the accepted conversions of dates from Mayan to the modern calendar may be off by as much as 50 or 100 years. That would throw the supposed and overhyped 2012 apocalypse off by decades and cast into doubt the dates of historical Mayan events. (The doomsday worries are based on the fact that the Mayan calendar ends in 2012, much as our year ends on Dec. 31.)

The Mayan calendar was converted to  Gregorian calendar using a calculation called the GMT constant, named for the last initials of three early Mayanist researchers. Much of the work emphasized dates recovered from colonial documents that were written in the Mayan language in the Latin alphabet, according to the chapter’s author, Gerardo Aldana, University of California, Santa Barbara professor of Chicana and Chicano Studies.

Later, the GMT constant was bolstered by American linguist and anthropologist Floyd Lounsbury, who used data in the Dresden Codex Venus Table, a Mayan calendar and almanac that charts dates relative to the movements of Venus.

Source:Livescience

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