CU News
News from the University of Colorado in Boulder.
CU study: We’re not so different than the Ancients
Feb 12th
Ancient settlements and modern cities follow same
rules of development, says CU-Boulder researcher
rules of development, says CU-Boulder researcher
Recently derived equations that describe development patterns in modern urban areas appear to work equally well to describe ancient cities settled thousands of years ago, according to a new study led by a researcher at the University of Colorado Boulder.
“This study suggests that there is a level at which every human society is actually very similar,” said Scott Ortman, assistant professor of anthropology at CU-Boulder and lead author of the study published in the journal PLOS ONE. “This awareness helps break down the barriers between the past and present and allows us to view contemporary cities as lying on a continuum of all human settlements in time and place.”
Over the last several years, Ortman’s colleagues at the Santa Fe Institute (SFI), including Professor Luis Bettencourt, a co-author of the study, have developed mathematical models that describe how modern cities change as their populations grow. For example, scientists know that as a population increases, its settlement area becomes denser, while infrastructure needs per capita decrease and economic production per capita rises.
Ortman noticed that the variables used in these equations, such as cost of moving around, the size of the settled area, the population, and the benefits of people interacting, did not depend on any particular modern technology.
“I realized that if these models are adequate for explaining what’s going on in contemporary cities, they should apply to any settlements in any society,” he said. “So if these models are on the right track, they should apply to ancient societies too.”
To test his idea, Ortman used data that had been collected in the 1960s about 1,500 settlements in central Mexico that spanned from 1,150 years B.C. through the Aztec period, which ended about 500 years ago. The data included the number of dwellings the archaeologists were able to identify, the total settled area and the density of pottery fragments scattered on the surface. Taken together, these artifacts give an indication of the total population numbers and settlement density of the ancient sites.
“We started analyzing the data in the ways we were thinking about with modern cities, and it showed that the models worked,” Ortman said.
The discovery that ancient and modern settlements may develop in similar and predictable ways has implications both for archaeologists and people studying today’s urban areas. For example, it’s common for archaeologists to assume that population density is constant, no matter how large the settlement area, when estimating the population of ancient cities. The new equations could offer a way for archaeologists to get a more accurate head count, by incorporating the idea that population density tends to grow as total area increases.
In the future, the equations may also guide archaeologists in getting an idea of what they’re likely to find within a given settlement based on its size, such as the miles of roads and pathways. The equations could also guide expectations about the number of different activities that took place in a settlement and the division of labor.
“There should be a relationship between the population of settlements and the productivity of labor,” Ortman said. “So, for example, we would expect larger social networks to be able to produce more public monuments per capita than smaller settlements.”
The findings of the new study may also be useful to studies of modern societies. Because ancient settlements were typically less complex than today’s cities, they offer a simple “model system” for testing the equations devised to explain modern cities.
“The archaeological record actually provides surprisingly clear tests of these models, and in some cases it’s actually much harder to collect comparable data from contemporary cities,” Ortman said.
Other co-authors of the study include Andrew Cabaniss of Santa Fe Institute and the University of North Carolina Chapel Hill and Jennie Sturm of the University of New Mexico.
The study is available at http://dx.plos.org/10.1371/journal.pone.0087902.
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CU students will do your taxes for free
Jan 29th
CU-Boulder students to offer free
tax preparation assistance
tax preparation assistance
Students from the University of Colorado Boulder’s Leeds School of Business will offer free tax preparation services to individuals under the Internal Revenue Service-sponsored Volunteer Income Tax Assistance program.
Members of the public who make $52,000 or less are eligible for the service, now in its fifth year at the Leeds School.
The assistance will be available only on a walk-in basis Feb. 1 through April 5 on Wednesdays from 5 to 7:30 p.m. and Saturdays from 9 a.m. to 2 p.m. in the Koelbel Business Building, room 375. The building is located at 995 Regent Drive on the CU-Boulder campus, across from the Coors Events Center. Free parking is available after 5 p.m. and during the weekends at lot 436/494, located on Regent Drive north of the Coors Events Center and east of the Koelbel Business Building.
“Not only do student volunteers perform a much needed community service, but their work also is well received by potential employers,” said Susan Morley, senior instructor of accounting at the Leeds School.
Participating Leeds students have passed an IRS certification exam. Community volunteers who are experienced in tax law will review all student-prepared tax returns to ensure accuracy and completeness.
Last year, Leeds School students prepared approximately 380 tax returns and obtained more than $518,000 in refunds for taxpayers. The students also placed an extra $152,000 into the local economy through Earned Income Tax Credits for families.
Taxpayers who are eligible for the assistance should bring the following:
— Social Security cards or Individual Taxpayer Identification Notices/Cards for the taxpayer, the taxpayer’s spouse and dependents.
— Photo identification for the taxpayer and the taxpayer’s spouse if married and filing jointly. Both spouses must be present.
— All W-2 and 1099 forms and other income-related documents.
— Proof of mortgage interest, property taxes, daycare expenses (including provider’s tax ID number), college education expenses (e.g., 1098-T form) and all other applicable deductible expenses.
— A copy of last year’s federal tax return.
— Proof of account for direct deposit of refund (e.g., voided check).
— Proof of foreign status if applying for ITIN.
For more information about the accounting division at CU-Boulder’s Leeds School of Business visit http://leeds.colorado.edu/accounting#overview. For more information about the Leeds School visit http://leeds.colorado.edu/.
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Climate change: Big changes for big mammals
Jan 23rd
New CU-Boulder study shows differences
in mammal responses to climate change
in mammal responses to climate change
If you were a shrew snuffling around a North American forest, you would be 27 times less likely to respond to climate change than if you were a moose grazing nearby.
That is just one of the findings of a new University of Colorado Boulder assessment led by Assistant Professor Christy McCain that looked at more than 1,000 different scientific studies on North American mammal responses to human-caused climate change. The CU-Boulder team eventually selected 140 scientific papers containing population responses from 73 North American mammal species for their analysis.
Large mammals, like this elk, are threatened by climate change
The studies assessed by the team examined seven different responses to climate change by individual mammal species: local extinctions of species known as extirpations, range contractions, range shifts, changes in abundance, seasonal responses, body size and genetic diversity. The researchers used statistical models to uncover whether the responses of the 73 mammals to a changing climate were related to aspects of their physiology and behavior or the location of the study population.
The analysis showed only 52 percent of the mammal species responded as expected to climate change, while 7 percent responded the opposite of expectations and the remaining 41 percent had no detectable response. The two main traits tied to climate change responses in the CU-Boulder study were large mammal body size and restricted times during a 24-hour day when particular mammal species are active, she said.
A paper on the study by McCain and former CU-Boulder postdoctoral fellow Sarah King was published online Jan. 22 in the journal Global Change Biology. The National Science Foundation funded the study. King is currently a research associate at Colorado State University.
While body size was by far the best predictor for response to climate change — almost all of the largest mammals responded negatively — the new study also showed that mammals active only during the day or only at night were twice as likely to respond to climate change as mammals that had flexible activity times, she said.
“This is the first time anyone has identified specific traits that tell us which mammals are responding to climate change and which are not,” said McCain of CU-Boulder’s ecology and evolutionary biology department.
McCain said she and King were surprised by some of the findings. “Overall the study suggests our large, charismatic fauna — animals like foxes, elk, reindeer and bighorn sheep — may be at more risk from climate change,” she said. “The thinking that all animals will respond similarly and uniformly to temperature change is clearly not the case.”
The researchers also found that species with higher latitudinal and elevation ranges, like polar bears, American pikas and shadow chipmunks, were more likely to respond to climate change than mammals living lower in latitude and elevation. The ability of mammals to hibernate, burrow and nest was not a good predictor of whether a species responded to climate change or not. American pikas have been extirpated from some of their previously occupied sites in the West, as have shadow chipmunks, which are in decline in California’s Yosemite National Park.
One of the most intriguing study findings was that some small mammals may shelter from climate change by using a wider array of “micro-climates” available in the vegetation and soil, she said. McCain compared the findings with the events at the K-T boundary 66 million years ago when an asteroid smacked Earth, drastically changing the climate and killing off the big dinosaurs but sparing many of the small mammals that found suitable shelter underground to protect them from the cataclysmic event.
“I think the most fascinating thing about our study is that there may be certain traits like body size and activity behaviors that allow some smaller mammals to expand the range of temperature and humidity available to them,” said McCain, also a curator of vertebrate zoology at the University of Colorado Museum of Natural History. “These areas and conditions are not available to bigger mammals that live above the vegetation and experience only ambient temperatures.”
The new study builds on a growing body of global information documenting the shifting behaviors and environments of organisms like flowers, butterflies and birds in response to a warming world, said McCain.
“If we can determine which mammals are responding to climate change and the ones that are at risk of disappearing, then we can tailor conservation efforts more toward those individual species,” said McCain. “Hopefully, this potential loss or decline of our national iconic mammals will spur more people to curb climate impacts by reducing overuse of fossil fuels.”
For more information on the ecology and evolutionary biology department visit http://ebio.colorado.edu. For more information on the University of Colorado Museum of Natural History visit http://cumuseum-archive.colorado.edu/About/directory.html.
