(Press-News.org) Ethnic segregation in nations straddling the world's steepest terrains may be reinforced by the biological tolerance different peoples have to altitude, according to one of the first studies to examine the effect of elevation on ethnic demographics.
Research from Princeton University published in the journal Applied Geography suggests that people native to low-lying areas can be naturally barred from regions such as the Tibetan Plateau, the Andes or the Himalayas by altitude sickness, which is caused by low oxygen concentration in the air and can be life-threatening. As a result, the homogeny of the local population can increase with elevation. In nations shared by people of high- and lowland extractions, this separation can potentially increase ethnic tension.
The researchers studied Tibet and found that elevation has heavily influenced the location of the surrounding region's population of Han Chinese, who make up 92 percent of China's population and originate from the country's eastern plains. Tibet has an average elevation of roughly 14,370 feet (4,380 meters) above sea level. The number of settlements with a large Han Chinese population peaks at around 8,900 feet (2,700 meters), while Tibetan settlements only begin to peter out beyond 17,000 feet (5,200 meters), the researchers found. The researchers attribute the sudden drop in the Han Chinese population to altitude sickness, and cite existing research showing that Han Chinese are indeed susceptible to altitude sickness in areas in which Tibetans thrive.
First author Christopher Paik, who undertook the study as a postdoctoral research scholar in the Empirical Studies of Conflict Project in Princeton's Woodrow Wilson School of Public and International Affairs, said that the research adds a new dimension to the study of how terrain influences demographic patterns. The field already explores the role of factors such as soil quality and access to the sea. The biological effects of elevation make altitude a particularly objective and reliable measurement for helping determine and understand how populations around the world's highest areas form, he said.
"There is very little research about the effect of altitude on migration patterns," said Paik, who is now an assistant professor of politics at New York University Abu Dhabi. "One of the nice things about using this geographical indicator as an independent variable is that there isn't any human intervention in determining the altitude of the region because it's established by nature.
"Rather than saying there is merely a correlation between settlement patterns and altitude, our research takes it one step further and suggests that altitude can directly determine the settlement patterns we see today. There's a causal story here," Paik said.
The separation that results from these settlement patterns could result in greater ethnic friction, Paik said. He initiated the current study in the wake of the 2008 unrest in Tibet, a series of protests that lead to imprisonment, detainment and clashes with Chinese security forces. Paik noticed that the most violent outbreaks occurred in areas of Tibet with the lowest relative concentrations of Han Chinese — regions that also have the highest elevations. (Paik is currently working on a paper that correlates lower levels of violence during the 2008 unrest with lower elevation and greater Tibetan/Han integration.)
Paik and co-author Tsering Shawa, who heads the Digital Map and Geospatial Information Center in Princeton's Lewis Library, used 2000 Chinese census data to determine the Han population in settlements within the traditional Tibetan homeland, which includes the Tibetan Autonomous Region as well as portions of the Chinese provinces Qinghai, Gansu, Sichuan and Yunnan. They also gauged past Han Chinese presence through maps and a database developed by Shawa that indicate whether the official name of the 1,960 settlements in this area is Han Chinese, Tibetan or both.
The researchers found a similar distribution pattern of towns where at least one-third of the population are Han Chinese and traditional Han settlements (most of which date as far back as the 13th century) — the bulk are located lower than 8,900 feet above sea level. No towns with a Chinese name exist above 15,000 feet (4,600 meters). Meanwhile, the greatest number of settlements with a Tibetan name stands at an only slightly lower elevation of 14,760 feet (4,500 meters), an area that the census shows has a minimum of Han Chinese inhabitants.
"What the outcome suggests is that there is a direct effect of altitude now as well as in historical settlement patterns," Paik said. "On the one hand there are settlements where Han Chinese came 1,000 years ago and established roots in that region, which makes it easier for migrants to come in. That provides a channel through which more Chinese live there today because their ancestors lived there as well.
"But if historical settlement is the only channel through which altitude influenced current settlement patterns, then there wouldn't be the direct influence of elevation through altitude sickness that we still see," Paik said. "Han Chinese still suffer from altitude sickness and the influence on settlement seems to persist today."
Paik and Shawa reference at least 10 studies that delve into the genetic adaption of Tibetans' blood cells and lung tissue to the low-oxygen conditions of a life on high — a tolerance research suggests they share with Andes dwellers in countries such as Bolivia.
Han Chinese do not enjoy this predisposition even in modern times. The researchers cite a 2009 paper in the journal Clinica Chimica Acta that explored the genetic susceptibility of Han Chinese laborers to the pulmonary edema — potentially fatal fluid buildup in the lungs — they experienced during construction of the Qinghai-Tibet railway completed in 2005.
"The main contribution of this research is to point out geography does matter in ethnic demographic patterns," said Enze Han, an assistant professor of politics and international studies at the University of London. Han, who had no role in the research but is familiar with it, agrees with the researchers when they write that modern technology and transportation makes migration into high-altitude lands easier.
But, Paik said, the population distributions he and Shawa document show that geography — via altitude sickness — continues to play a strong role in regional diversity despite modern trappings such as the Qinghai-Tibet railway and government initiatives such as China's Western Development Program.
"Ethnic integration policy seems to work in the long run, but it will be harder to implement in the higher altitude regions," Paik said. "There seems to be a strong enough influence of altitude on settlement patterns such that even if you try to have integration happening there, nature works against those initiatives."
The paper, "Altitude and adaptation: A study of geography and ethnic division," was published in the June 2013 edition of Applied Geography. This work was supported by a grant from the Air Force Office of Scientific Research (AFOSR) award number FA9550-09-1-0314.
Altitude sickness may hinder ethnic integration in the world's highest places
ELSE PRESS RELEASES FROM THIS DATE:
Doctor-patient communication about dietary supplements could use a vitamin boost
Vitamins, minerals, herbs and other dietary supplements are widely available in supermarkets and drug stores across the nation without a prescription, so it's no surprise that nearly half of all Americans take them. But they do carry risks, including potentially adverse interactions with prescription drugs, and some people may even use them in place of conventional medications. So it's important that primary care physicians communicate the pros and cons of supplements with their patients. In fact, both the Food and Drug Administration and the National Institutes of ...
New American Chemical Society video focuses on ancient secrets of alchemy
The pursuit that obsessed some of the world's greatest geniuses for centuries — alchemy and its quest for the "Philosopher's Stone" that would transform lead and other base metals into gold — is the topic of a new episode in the American Chemical Society Bytesize Science video series. The video, from the world's largest scientific society, is at http://www.BytesizeScience.com. It features Laurence Principe, Ph.D., a noted historian of science and expert on alchemy, which, far from being solely a misguided pseudoscience, helped set the stage for the emergence of modern ...
Biomedical research revealing secrets of cell behavior
TEMPE, Ariz -- Knowing virtually everything about how the body's cells make transitions from one state to another – for instance, precisely how particular cells develop into multi-cellular organisms – would be a major jump forward in understanding the basics of what drives biological processes. Such a leap could open doors to far-reaching advances in medical science, bioengineering and related areas. An interdisciplinary team of researchers at Arizona State University, with a partner at Imperial College London, report on taking at least a step toward better comprehension ...
Vitamin C helps control gene activity in stem cells
Vitamin C affects whether genes are switched on or off inside mouse stem cells, and may thereby play a previously unknown and fundamental role in helping to guide normal development in mice, humans and other animals, a scientific team led by UC San Francisco researchers has discovered. The researchers found that vitamin C assists enzymes that play a crucial role in releasing the brakes that keep certain genes from becoming activated in the embryo soon after fertilization, when egg and sperm fuse. The discovery might eventually lead to the use of vitamin C to improve ...
Cattle flatulence doesn't stink with biotechnology
The agriculture industry is researching new technologies to help feed the growing population. But feeding the world without harming air quality is a challenge. According to a new article in Animal Frontiers, biotechnologies increase food production and reduce harmful gas output from cattle. "We are increasing the amount of product with same input," said Clayton Neumeier, PhD student at University of California, Davis, in an interview. In the Animal Frontiers paper, Neumeier describes a recent experiment using biotechnologies. In the experiment, a test group of cattle ...
UCSB astronomer uncovers the hidden identity of an exoplanet
(Santa Barbara, Calif.) –– Hovering about 70 light-years from Earth –– that's "next door" by astronomical standards –– is a star astronomers call HD 97658, which is almost bright enough to see with the naked eye. But the real "star" is the planet HD 97658b, not much more than twice the Earth's diameter and a little less than eight times its mass. HD 97658b is a super-Earth, a class of planet for which there is no example in our home solar system. While the discovery of this particular exoplanet is not new, determining its true size and mass is, thanks to Diana Dragomir, ...
It's about time: Disrupted internal clocks play role in disease
Thirty percent of severe alcoholics develop liver disease, but scientists have not been able to explain why only a subset is at risk. A research team from Northwestern University and Rush University Medical Center now has a possible explanation: disrupted sleep and circadian rhythms can push those vulnerable over the edge to disease. The team studied mice that essentially were experiencing what shift workers or people with jet lag suffer: their internal clocks were out of sync with the natural light-dark cycle. Another group of mice had circadian disruption due to a faulty ...
Head Start children and parents show robust gains in new intervention
EUGENE, Ore. -- An eight-week intervention involving 141 preschoolers in a Head Start program and their parents produced significant improvements in the children's behavior and brain functions supporting attention and reduced levels of parental stress that, in turn, improved the families' quality of life. The findings -- from the first phase of a long-term research project by University of Oregon neuroscientists that will monitor the families over time -- appear this week online in advance of regular publication in the Proceedings of the National Academy of Sciences. The ...
Mapping the benefits of our ecosystems
MADISON — We rely on our physical environment for many things – clean water, land for crops or pastures, storm water absorption, and recreation, among others. Yet it has been challenging to figure out how to sustain the many benefits people obtain from nature — so-called "ecosystem services" — in any given landscape because an improvement in one may come at the cost of another. Two ecologists at the University of Wisconsin–Madison report this week (July 1) in the Proceedings of the National Academy of Sciences a novel approach to analyzing the production and location ...
Univ. of Maryland review finds mixed results for acupuncture to improve in vitro fertilization rates
Baltimore, MD – June 28, 2013. Acupuncture, when used as a complementary or adjuvant therapy for in vitro fertilization (IVF), may be beneficial depending on the baseline pregnancy rates of a fertility clinic, according to research from the University of Maryland School of Medicine. The analysis from the University of Maryland Center for Integrative Medicine is published in the June 27 online edition of the journal Human Reproduction Update. "Our systematic review of current acupuncture/IVF research found that for IVF clinics with baseline pregnancy rates higher than ...