Print Page   |   Contact Us   |   Sign In   |   Register
Complexity Matters
Blog Home All Blogs
The Complexity Matters blog features the Thursday Complexity Post as well as other complexity inspired news items.

 

Search all posts for:   

 

Top tags: complexity matters  buscell  health  research  culture  stopMRSA  news  cohn  community  innovation  nature  catching butterflies  MRSA  education  healthcare  neuroscience  medicine  positive deviance  leadership  relationships  resilience  music  science  technology  networks  art  environment  leaders  organizations  ecology 

Zero is Abstract and Mysterious, but Never Odd

Posted By Prucia Buscell, Thursday, November 15, 2012

When New York Mayor Michael Bloomberg imposed odd-even gas rationing in the city, he announced that people with license plates "ending in an even number or the number zero will be able to buy gas or diesel only on even numbered days.”

So does that mean zero is an even number?

A New York Times story by Vivian Yee addresses this issue. Yee quotes Walter Neumann, chair of Barnard College mathematics department, who says there’s no question. He explained that even integers, or whole numbers, are numbers that can be divided by two without producing a non-whole number. Four divided by two equals two, five divided by two produces 2.5. Zero divided by two equals zero, with no fraction or decimal left. So that should settle it, right?

Professor Hossein Arsham of the University of Baltimore who has written about the concept of zero, told the Times that when an odd-even license plate driving system was imposed in Paris in 1977 to reduce traffic during a smog alert, people whose plate numbers ended in zero drove around whenever they wanted because police weren’t sure how to categorize zero.

Roots of the concept of zero are shrouded in the deep past. The Babylonians used a symbol considered to be an ancestor of zero as a place holder—a mark used to distinguish—in our numbers—the difference between 1, 10 and 100. The ancient Greeks contemplated the philosophical question of how nothing could be something, and wondered about the existence of zero and the concept of the vacuum.

A Scientific American article by John Matson says the number zero as we know it today was brought to the West about 1200 by the Italian mathematician Leonardo of Pisa, also known as Fibonacci, who learned about Hindu-Arabic numerals when he traveled in North Africa. Fibonacci, considered the most talented Western mathematician of the Middle Ages, realized the Arabic system made math more efficient than using Roman numerals, and published a book that popularized the system in Europe. Matson quotes Charles Seife, the author of Zero: The Biography of a Dangerous Idea, as explaining that the idea originated in the Fertile Crescent around 350 BCE, developed in India and moved through North Africa before Fibonacci found it. He explains that a "full throated zero” isn’t just a place holder, it’s the average of minus one and plus one.

Matson also quotes Robert Kaplan, the author of The Nothing That Is: A Natural History of Zero, as explaining that zero as a number in its own right began to take shape in India, in the fifth century AD. But he says it was slow to spread because in some cultures, the notion of zero had dark and magical connotations. Interestingly, he adds, the idea of zero appeared in Mayan culture in the New World, apparently from scratch, independent of discoveries elsewhere.

In New York, motorists with plates ending in an odd number or a letter could fill up on odd numbered days. When Gov. Chris Christie announced odd-even gas rationing in New Jersey—which was in effect from Nov. 3 to Nov. 12—the philosophical and mathematical nature of zero was left officially unaddressed, as was the positioning of letters on the plate. Some drivers whose license plates ended with letters rather than numbers thought they might get away with exemption from the rule, but that didn’t fly with police, gas station attendants, or motorists waiting in lines.

This post has not been tagged.

Share |
PermalinkComments (0)
 

Evidence and Belief: The Link Isn't Linear

Posted By Prucia Buscell, Thursday, November 8, 2012
Updated: Sunday, November 11, 2012

Will the "Frankenstorm" that devastated much of the Northeast and the recent hurricanes, droughts, disastrous heat waves and fires in other parts of the U.S. produce a critical mass of extreme weather awareness that generates broad public support for action on global warming? Psychology and social science scholars say don't count on it.

Daniel T. Blumstein, Professor and Chair of the Department of Ecology and Evolutionary Biology at UCLA, writes that the military knows the evidence for human-induced climate change is overwhelming and is working hard to develop renewable sources of energy and plan for huge refugee crises and enhanced competition for arable land, water and fuel. The insurance companies know it, too, he says, and are raising rates. So what is to doubt?

Yale Professor of Law and Psychology Dan Kahan in his essay "Why We Are Poles Apart on Climate Change" says people don't ignore science because they are irrational, "it is that their reasoning powers have become disabled by a polluted science communication environment." As he puts it, people are quite rational to filter out information that would drive a wedge between themselves and their peers. Positions on climate change have come to say a great deal about who we are and what values we hold. The personal cost of holding a view that's at odds with scientific consensus is zero, but the cost of a view at odds with our friends, colleagues or customers could be very high. Even some scientifically literate people may find greater value in being attuned to their social environments.

While accurate climate information is readily accessible, Kahan comments, "trouble starts when the communication environment fills up with toxic partisan meanings-ones that effectively announce 'if you are one of us, believe this; otherwise we'll know you are one of them.'"

In his New York Times DotEarth blog, Andrew Revkin provides thoughtful analysis on why successive climate disasters may not engage the public in the enormous challenge of "getting carbon out of the world's energy system." He quotes George Marshall, an expert on climate and communication, on what he learned from interviewing people in Bastrop County, Texas, where the worst wildfires in the state's history destroyed 1,691 homes in September and October 2011. People connected the extreme heat and drought with the fires, but didn't relate it to climate. They stressed their pride in community and collective ability to overcome challenge.

Marshall writes in his blog that when natural disasters increase social confidence and reinforce social networks, it may be actually more difficult for people to contemplate information that challenges their existing world view, so there's an even greater obstacle for accepting climate change if the prevailing attitude is skeptical. Disasters may in fact reinforce existing views. He notes that the area struck by "Frankenstorm" Sandy is largely Democratic, and attitudes about climate change are often part of political identity. So if residents of New York and New Jersey emerge with stronger belief in climate change, it doesn't necessarily prove extreme events change views.

Marshall compares two narratives about the fires:

  • One: We're tough, we're a community that pulls together with love and kindness, we face our challenges, support each other, and get through.

  • Two: The fires may have been caused in part by weather conditions, which may have been caused in part by climate change, which might have been caused in part by the culture and behavior of Bastrop residents.

As Marshall says, the first is very attractive and easy to sell. The second is neither.

Professor Blumstein says it's urgent for policy makers and citizens to act. Environmentalist Bill McKibbon, who has been warning about climate change for decades, told Time magazine that 74 percent of the U.S. public thinks the planet is warming, but that politicians of both parties haven't wanted to take on the fossil fuel industry.

This post has not been tagged.

Share |
PermalinkComments (0)
 

RX for Managing Diabetes: Trust and Communication

Posted By Prucia Buscell, Thursday, November 1, 2012

Diabetes cost the nation about $100 billion a year, and researchers say some of the most powerful preventive measures are behavior changes among care providers as well as life style changes among people who have the illness and are at risk to get it.

Monica Peek, MD, is a Robert Wood Johnson Foundation Harold Amos Medical Faculty Development Program scholar who studies how the social determinants of health impact African Americans. In an October 2012 presentation at the American Public Health Association, and a recent article described on the RWJF website, Dr. Peek reports: "We found that race, as a social construct, has the potential to influence two key domains of patient trust-interpersonal relationships and medical skills and technical competence. For example, African Americans in our study were concerned that physicians might be biased or using them in medical experiments without their consent. This influenced their perceptions about physicians’ overall competence, bedside manner, and ability to provide them with high-quality care.”

Research has shown that when diabetics engage in shared decision making with their care providers, their compliance with medication regimens, healthy life style choices, and management of blood pressure and blood glucose improve. In their paper "Patient Trust in Physicians and Shared Decision Making Among African Americans with Diabetes," Dr. Peek and colleagues say methods of building trust include enhanced patient education, physician training in interpersonal skills and cultural competence and efforts to engage patients in decision about their care. Although her research focused on African Americans, Dr. Peek believes the findings are applicable to other ethnic and cultural groups struggling with diabetes.

Dr. Peek is also an assistant professor of medicine at University of Chicago Medicine and co-principal investigator of an innovative project called Improving Diabetes Care and Outcomes on the South Side of Chicago, where high rates of diabetes impact a large African American population. The project involves collaboration among six clinics, academic institutions, and community organizations and businesses to provide education and increase access to care. In one program, a nutritionist toured grocery stores with diabetes patients, illustrating healthy food choices, and showing how label information can help manage carbohydrate and sugar intake. In a Food RX initiative, patients who visit one of the clinics can get a coupon for $5 off a $20 order of healthy food at participating Walgreen stores, and a $3 voucher for a weekly farmers market. Dr. Peek says the initiatives put the power of a doctor’s prescription behind nutritional advice. Because many shoppers were buying food at Save-A-Lot stores, initiative leaders established a relationship with the chain, which is now opening more stores in "underserved” neighborhoods that have been described as a "food deserts” and is offering educational information to customers. The store also sponsored a diabetes awareness cooking contest for healthy recipes.

The Improving Diabetes Care and Outcomes project is funded by the Merck Company Foundation through its Alliance to Reduce Disparities in Diabetes across five U.S. cities, and the National Institutes of Health, with the University of Chicago’s Institute for Translational Medicine.

This post has not been tagged.

Share |
PermalinkComments (0)
 

Organizations Can Take Cues from Natural Systems

Posted By Prucia Buscell, Thursday, October 25, 2012


"The Fruits of Success Contain the Seeds of Destruction"

To business theorist David K. Hurst, the 48-year emergence of Walmart into a mature large scale enterprise is similar to what happens in a forest ecosystem. Walmart began in the 1960s with two dozen small outlets in rural Arkansas. Today it is the biggest private employer in the U.S, with 1.4 million employees and more than 4,300 stores.

In an article in Strategy + Business, Hurst explains how forest succession, the processes of evolving change in an ecological community in the temperate zone, begins in an open patch of land where all plant life has unfettered access to sun and rain. He says weeds and wondering creatures that spread seeds, which he calls the entrepreneurs of the ecosystem, thrive because they have ready resources and no competition. As they flourish and compete, the plants and shrubs that have the best infrastructure-the deepest roots to get water first and leaves and branches that get the light-begin to dominate, and the growth of their competitors is stunted. Shrubs are then succeeded by soft wood trees, such as conifers that shed their needles on the forest floor, making fuel for fire, which allows their hard seeds to germinate. In the climax phase of forest succession, hardwood trees, such as oak, will overwhelm the pines. Their accumulated leaves create a layer of damp mold on the forest floor, which inhibits fire and lets acorns germinate.

The appearance of the hardwood trees used to be considered a sign of ecological equilibrium, Hurst observes, but now scientists know it isn't. It's the climax phase of the cycle. "Reduction in the variety of organisms in the ecosystem leads inexorably to a lack of resilience in the face of change," Hurst writes. "Too many trees of the same species and similar age are vulnerable to the same challenges, such as wind, disease and insect attack. The conditions are now right for a sudden catastrophe that will sweep away mature growth and open up the system for renewal."

So far, Hurst writes, Walmart's adaptability has helped the organization avoid the hazardous parts of maturity. Hurst concedes analysis cite many reasons for the company's success-ranging from entrepreneurial and logistical prowess to predatory pricing and the abuse of labor laws. But he thinks the ecological analogy is especially useful.

In the early years, traditional wholesalers didn't want to make small deliveries to remote rural spots, so Walmart developed its own distribution infrastructure and innovative logistics system. For example, Walmart adopted a cross docking system used by the military, in which goods received from suppliers are quickly shipped to branches, with minimum use of warehousing. Hurst notes founder Sam Walton often identified his store sites from the air. Architect Jesse LeCavalier, describing the network of modern sites in a Design Observer article, writes that 60 percent of the U.S. population lives within five miles of a Walmart, and 96 percent is within 20 miles. The predesigned buildings are adapted to local environments, and surrounded by acres of rural and suburban parking.

While Walmart's growth would put it in the hardwood phase, it has diversified as well as adapted to remain resilient, Hurst says. Its original discount stores are gradually being replaced by newer supercenters that sell food and multiple services along with conventional merchandise. Hurst says a new category of smaller neighborhood Walmart stores is similar to the ecological "shrubs" in that these stores produce only modest profits but inhibit growth of such rivals as dollar stores.

Hurst, the author of The New Ecology of Leadership: Business Mastery in a Chaotic World, offers an ecological perspective for business success:

  • Think of organizations as movements rather than structures
  • Realize change and disruption are inevitable. Prescribed burns and release of "pulses" of water from dams to renew rivers are examples of interventions to manage natural systems
  • Pursue change on the edges, in open places, where variety can thrive on a small scale, with little competition.
  • Remember the fruits of success always contain the seeds of destruction.
  • Creation requires destruction. Look for openings in turbulent markets, where information is scarce and navigation unclear.

This post has not been tagged.

Share |
PermalinkComments (0)
 

Crowd-Sourcing, Greed, Ingenuity: A Cancer Cure?

Posted By Prucia Buscell, Thursday, October 18, 2012

MIT Finance Professor Andrew Lo believes financial engineering can provide the money and motivation to cure cancer within two decades.

Lo, who is director of the Laboratory for Financial Engineering at the MIT Sloan School of Management, also runs the AlphaSimplex group, an investment firm with $3 billion in assets. Time magazine named him one of the year’s 100 most influential people in the world, and notes he has challenged traditional economics with his belief that markets have more in common with biological systems than they do with rule based physics. He applies evolutionary and neurobiological models to finance and risk. As Time describes his approach, "Market participants aren’t coldly rational creatures but squirmy evolving species interacting with one another in a primordial sludge of money.”

In one of his lectures, Lo observes cancer is not a single disease, but a complex collection of more than 200 diseases. He lost his mother to lung cancer, and notes nearly everyone has been touched in some way by the disease. Government and private sources already pour billions into cancer research, but Lo thinks new methods are needed to foster drug research and development, and he believes the recent financial crisis provide lessons on how that can be achieved. .

He proposes creation of a $30 billion megafund with money from a large number of individual and institutional investors that could support as many as 150 simultaneous research projects. Right now, he says, a typical clinical trial costs $200 million, takes 10 years, and has a five percent chance of success. While researchers have discovered as many as 200 compounds that might be useful in treating cancers, he says, only a small portion of that potential can be investigated under the present system. In his view, crowd-sourcing combined with an appeal to both greed and social conscience can promote a new way of financing large scale biomedical innovation.

A small scale example of how a megafund might work, he says, is the Defense Advanced Research Projects Agency (DARPA) balloon experiment in 2009. The agency placed 10 large red weather balloons throughout the country and offered a $40,000 reward to the team that could find them all first. The MIT Lab team, which won the challenge in less than nine hours, explained the secret to success was financially rewarding not only the individuals who reported the location of the balloons, but everyone who helped in any way.

Lo says the extraordinary growth of the housing market in the decade before 2006 shows what vast sums of money can be generated and analysis of the subsequent crashes suggests the stability of the financial system can be maintained by strict enforcement of rules on sales practices, disclosure, corporate governance, and suitability criteria for investors. The megafund would be a portfolio entity that could raise money by issuing debt and could use financial engineering techniques such as securitization to create a new kind of investment called a Research Backed Obligation. The new system, with its mix of equities, could potentially spread risk, maximize capital, expand research, and generate returns ranging from five to eight percent, depending on the investor’s chosen risk. Lo plans a conference next year, where cancer scientists, financial experts and large institutional investors will be invited to discuss details of how a megafund could be created and managed. Read "Commercializing biomedical research through securitization techniques," by Lo, Jose-Maria Fernandez and Roger Stein in Nature Biotechnology online and a Boston Globe story by Beth Healy. Lo thinks the same financial engineering techniques can address energy and climate change issues.

This post has not been tagged.

Share |
PermalinkComments (0)
 

Vital Signs: Taking the Measure of Clinical Teams

Posted By Jeff Cohn, Wednesday, October 17, 2012
Updated: Friday, September 19, 2014

Last month I attended the 11th International Conference on Complexity in Acute Illness in Ottawa along with former Plexus President Curt Lindberg. The conference was primarily focused on developing applications of the theories of Plexus Advisor Ary Goldberger, who has described the complexity of normal heart and lung physiology, and how a loss in that complexity could indicate emerging illness. Numerous speakers, representing disciplines of critical care medicine, surgery, informatics, mathematical modeling, and physics, described how these concepts could potentially lead to earlier recognition of potentially reversible illness. Patient populations described included critically ill infants, burn patients, major trauma patients, and adult patients on ventilators, just to name a few.

At the same conference we heard a presentation from Curt Lindberg about Billings Clinic and how focusing on changing and improving relationships is leading to healthcare delivery innovations. John Scott, MD, described his research on what patients and physicians have mutually agreed are "healing relationships” that involve factors such as mindfulness, valuing, appreciating power, and abiding. And Heather Mattila, PhD, from Wellesley, presented some of her research regarding the role of diversity in ensuring the health of honeybee colonies.

This caused me to think about the convergence of factors associated with restoring seriously ill patients to health. These patients are connected to numerous monitors that give important information to the group of clinicians providing care. Soon we may have additional monitoring capabilities to identify loss of complexity, which could enable caregivers to respond earlier and provide more effective rescue care. But then what? Once team members have the information, they need to go into action to provide the care the patient needs. And how do we know whether, at that moment, the team is "healthy” enough to provide that care? What is the status of the relational coordination (the subject of a recent Plexus call) of the team providing care? What is staffing like? Fatigue? How quickly are clinicians responding to their patients’ changes in condition? What if we had the ability to stream this kind of information together and have that displayed on monitors, reflecting the unit’s "health?” Maybe the unit’s vital signs are as important in determining the outcomes of care as the vital signs of the patients for whom they’re providing care. Please share any thoughts or ideas you have below, or email me at jeff@plexusinstitute.org.

Tags:  catching butterflies  cohn  complexity  health  healthcare  relationships 

Share |
PermalinkComments (0)
 

A Helping of Behavior Change With Lunch

Posted By Prucia Buscell, Thursday, October 11, 2012

New Law, Shape Up Somerville, and a French Lesson

Under the newly implemented Healthy, Hunger-Free Kids Act schools are required to serve nourishing lunches with fewer calories, less fat and mandatory fruits and vegetables. But legislation can’t make kids eat what’s good for them, and often they won’t.

Across the country youngsters who miss their habitual chocolate milk, cookies, french-fries and cheese nachos are rebelling by slipping away to buy junk food from school vending machines and off campus merchants, and brown bagging goodies from home. Some student have posted YouTube videos mocking the meals, singing protest songs, and feigning collapse from hunger.

A New York Times story by Vivian Yee describes a lunch strike in a Pittsburgh suburb and a boycott in town near Milwaukee. In New Jersey more than 1,200 people have joined a Facebook group urging Parsippany Hills High School students to boycott school lunches. The Times story is accompanied by a photo showing the mandatory vegetables and fruits in the lunch room trash.

While there formerly was no restriction on calories, new requirements limit high school lunches to 850 calories, and middle school lunches to 700 calories. Elementary school lunches are limited to 650 calories. Kids who throw away substantial portions will have even fewer calories. If schools still serve fries and pizza, the portions are smaller, have less fat, and the pizza is likely to have whole wheat crust and low fat cheese. Portions of meats and carbohydrates are smaller and fruits and vegetables aren’t always appreciated. Obesity is known to cause and exacerbate many chronic diseases, including diabetes, heart trouble and cancer, and obesity an chronic illnesses in the U.S. have been increasing for decades. The CDC reports that some 12.5 million children and adolescents between ages 2 and 19 are obese-that’s 17 percent of that age group, and poor kids are especially prone to obesity. Among low income preschool children, the CDC reports, one in seven is obese.

What can influence youngsters to like eating eat what’s good for them? The Times story quotes William McCarthy, a professor of public health and psychology at the university of California at Los Angeles. He says research shows kids need to be exposed to vegetables 10 to 12 times before they will start to eat them on their own, so one strategy is just waiting. Several school districts are providing lessons about healthy eating in class, offering free samples, creating gardens kids can tend, and educating students about locally grown food.

Even before the recent law, some efforts have been intense and long range. Shape Up Somerville, Eat Smart Play Hard, funded by the CDC, began in 2002 as a three-year environmental change initiative designed to prevent obesity in early elementary school children. Tufts University researchers found that nearly half of the school district’s first graders were overweight or at high risk of being overweight. The initiative, led by Tuft’s Christine Economos, PhD, involved the whole community-schools, restaurants, businesses, and families, and emphasized exercise and play as well as healthy food. The body mass index of participating children declined, and community support continues.

The French are proud of their cuisine, and public schools in France are serious about promoting appreciation for healthy food as well as practice in the social graces of eating. Even young children receive several courses with small portions, and they sample traditional face such as escargot, bouillabaisse, and ratatouille. A CBS news story illustrates a public philosophy and the dedication of chefs. Karen LeBillon is a teacher, author and mother who blogs about French school food, describing among other delicacies the beets, goat cheese, fish, fruit and freshly baked bread being served to youngsters in public schools in Paris. In some schools, parents have chosen to pay extra for organic meals. Obesity has increased in France, although the rate of obesity among children and adults is lower than it is in other European countries and the U.S.

This post has not been tagged.

Share |
PermalinkComments (0)
 

Canadian Study: 40% Would Pay Kidney Donors

Posted By Prucia Buscell, Thursday, October 4, 2012

Researchers at the University of Calgary have found a significant public support for financial incentives for kidney donors.

An online survey was conducted with more than 2,000 members of the Canadian public, 339 health professionals, and 268 people who have or are affected by kidney disease. Forty percent of the respondents thought it was acceptable to pay living donors for kidneys, and 70 percent favored some financial compensation such as payment of funeral expenses for donors whose kidneys were harvested after death. However, few respondents favored payments to a deceased donor’s estate.

Interestingly, only 14 percent of health professionals thought it would be a good idea to pay living donors. The study, "Attitudes Toward Strategies to Increase Organ Donation: : Views of the General Public and Health Professionals,” is published in the Clinical Journal of the American Society of Nephrology.

According to a story by Lindsay Abrams in TheAtlantic.com, people who oppose payment most often said they thought "a kidney should be donated from the goodness of the heart.” At the same time, the authors concluded people might be more willing to donate if they were paid. More than half of the respondents who said they would not be living donors to a stranger indicated they’d reconsider if they were paid $10,000.

A U.S. study by researchers at the University of Pennsylvania and the Philadelphia Veterans Affairs Medical Center asked 342 participants whether they would be more likely to donate a kidney if they were paid differing amounts, $10,000 and $100,000. Promise of cash nearly doubled the number who said they would donate their organ to a stranger. The study was published in the March 16, 2010 issue of the Annals of Internal Medicine.

It is illegal to buy and sell organs in the U.S. and most western countries. The issues involved are difficult, emotional, ethical and complex. The people who die awaiting transplants greatly outnumber the organs available and advocates for increasing the supply argue that a regulated market could avoid exploitation and save lives. There are periodic international and domestic scandals about a trade in human organs. And the 2002 movie "Dirty Pretty Things" directed by Stephen Frears is memorable for its dark plausibility: the story deftly depicts criminals who profit by selling the organs of poor immigrants in London. A writer in the McGill Journal of Medicine asks whether it’s time for western countries to follow the example of Iran, which has long had a government regulated and funded kidney transplant system with an independent third party association to make arrangements and pay the donors.

But a shortage of donated organs is not the only barrier to life-saving transplants. Kevin Sack in a New York Times story September 19, 2012, reports that while 4,720 people died in the U.S. last year awaiting transplants, more than 2,600 kidneys from deceased donors were discarded. Some of the kidneys were found to be unsuitable, but Sack quotes experts who believe as many as half of them could have been transplanted if the U.S. donated organ allocation system did a better job getting the right organ to the right recipient in the right amount of time. The system needs to be revised, according to these experts, to consider better matching in terms of projected life expectancies of recipients and the very tight time frame for testing, evaluation, decisions and transportation. Surgeons want to transplant kidneys within 24 to 36 hours after removal from the donor.

This post has not been tagged.

Share |
PermalinkComments (0)
 

The ‘Anternet’—Ancient and Cutting Edge

Posted By Susan Doherty, Thursday, September 27, 2012
Updated: Thursday, September 27, 2012

Harvester ants may increase knowledge about networked systems.

Deborah Gordon, a Stanford biology professor who has studied ants for 20 years, found something extraordinarily sophisticated about the way harvester ants forage for food. She discovered that the ant colonies regulate their foraging activities based on the amount of food available and the amount of time it takes for a round trip between the nest and the food.

Harvester ant foragers waiting inside the nest. – photo by Katherine Decktar, one of the researchers

Gordon recognized that this particular ant behavior approximates the way the Internet works, so she invited Stanford Computer Science Professor Balaji Prabhakar to have a look. Their collaboration is described in a Stanford News story about "the anternet” and their paper is published in Plos Computational Biology.

Individual ants leave the nest looking for the seeds, which they immediately bring back and drop deep into the nest. The more food they find, the faster they return. New foraging trips are initiated based on the rate of return from earlier trips. There’s no central control or boss ant, and no geographic information on where the food is located. Some ants leave pheromone trails in their travels, but these ants don’t. What happens is based on local interactions among the ants in the nest. New foraging trips are signaled by the rate of contact between the antennas of returning ants and the antennas of ants available to leave on the next trip.

Initially skeptical, Prabhakar quickly saw the validity of Gordon’s insight. "The algorithm the ants were using to discover how much food there is available is essentially the same as that used in the (Internet) Transmission Control Protocol,” he told the Stanford News.

The Transmission Control Protocol, or TCP, is the way information transmission among networked computers is regulated. As the Stanford story explains TCP, as a source A sends a file to a destination B, the file is broken up into numbered packets. Each time B gets a packet, it sends an acknowledgment, or ack, back to A. Speed of ack return indicates the amount of bandwidth available. If the ack comes back at a lower speed than it was sent, it means little bandwidth is available, and transmission traffic is slowed accordingly. If it returns quickly, transmission speed can increase. That’s pretty much the same thing the ants do.

The researchers found another similarity: When a data link is disrupted or broken, the source stops sending packets. If forager ants don’t get back to the nest in 20 minutes, no more ants leave to forage.

Each ant is limited, but colonies can achieve some impressively complex computations, and they’ve been evolving for millions of years, probably doing things humans haven’t thought up yet. Read Gordon’s wonderful essay "Colonial Studies."

"Ant algorithms have to be simple, distributed and scalable—the very qualities that we need in engineering distributed systems,” Gordon said. "I think as we start understanding more about how species of ants regulate their behavior, we will find many more useful applications for network algorithms.”

This post has not been tagged.

Share |
PermalinkComments (0)
 

Social Network Analysis Finds Truth in Myth

Posted By Prucia Buscell, Thursday, September 20, 2012
Beowulf wrestles 
with Grendel 
1933 Lynd Ward

 

An ancient tale tells us the monster Grendel, annoyed by the noise of warriors drinking and carousing in the great mead hall built by the Danish King Hrothgar, was moved to murder them all in their sleep. No one thinks the monster was real, but there may have been a real mead hall. While evidence is lost and blurred by passing centuries, the story of Beowulf, the mythical hero who slew the monster, may be rooted in actual events and places.

 

Historians, archeologists and literary scholars have long searched for evidence of reality hidden in ancient myths that have been altered and embellished with every retelling for centuries even before they were committed to writing. Now the science of social network analysis is offering new clues about what’s rooted in reality and what’s totally fictional.

 

Achilles tending the wounded 
Patroclus from The Iliad

A team of physicists mapped the social networks in three ancient narratives by creating a database of the characters and their interactions and categorizing their relationships as hostile of friendly. Beowulf contained 74 characters, The Iliad 716, and the Irish legend Tain Bo Cuailnge contained 404 characters. Padraig MacCarron and Ralph Kenna, physicists at the Applied Mathematical Research Centre at Coventry University in the United Kingdom, describe their work in "Universal Properties of Mythological Networks" from epljournal.org, a Letters Journal Exploring the Frontiers of Physics, and in the New York Times story "If Achilles Used Facebook...."

 

Scholars think Beowulf, the heroic epic set in sixth century Scandinavia, has historical inspiration. The Iliad’s Greek gods who intervened in a mythical Trojan War with their supernatural powers come from the realm of art and imagination. But the lives and times described may refer to happenings in the 8th century BCE, and archeologists think Homer, writing some 400 years later, is likely to have incorporated re-told and remembered tales of military conflict around Troy at the end of the Bronze Age.

 

Cuchulainn
Slays the Hound of Culain 
1904 Eleanor Hull
The Boys' Cuchulain

Many scholars have considered "Tain Bo Cuailnge" completely fictional. Often translated as the Cattle Raid of Cooley, the story tells how the rulers of Connaught make war on Ulster in order to steal a fabulously potent stud bull. Cu Chulain, a 17-year-old, is Ulster’s sole defender. John Bohannon writing in news.sciencemag.org says recent archeological evidence suggests it could be based on real conflict 3,200 years ago in Ireland. Written manuscripts dating from 12th and 14th centuries tell of a fight between Connaught and Ulster in the north and west of Ireland, and social network analysis lends credence to the historical root.

 

Kenna and MacCarron found the mythical networks have characteristics of real world networks. All three have structural balance, which the authors explain is related to the real-world idea that the enemy of my enemy is my friend. They are small world networks, meaning connectivity among nodes leads to pathways that link a large number of nodes, and there never are more than a few degrees of separation between two people. They are scale free because their structure and dynamics are independent of the number of nodes in the network, and they were also highly clustered, with groups of people who are well connected. In addition, the networks were assortative, meaning that as in the real world, people connect with people who are similar to them.

 

The authors examined social networks in several intentionally fictional narratives, such as Harry Potter, and found that none were scale free. In most modern fiction, Bohannon explains, minor characters generally link to the main character. Bohannon quotes Kenna as saying that in deliberate fiction, everyone tends to be linked to everyone else in order to make the story easier to follow. Unlike the real-world and studied mythical networks, the fictional networks were disassortative, indicating many connections between unlike nodes.

 

As the authors explain in their Times piece, their approach is not literary or historical, and tells nothing about the human condition. "Instead,” they write, " it promises a new way to analyze old material and find striking new perspective and evidence-in this case, that which we call ‘myths’ may not be as mythical as we thought.”

This post has not been tagged.

Share |
PermalinkComments (0)
 
Page 25 of 45
 |<   <<   <  20  |  21  |  22  |  23  |  24  |  25  |  26  |  27  |  28  |  29  |  30  >   >>   >| 
Association Management Software Powered by YourMembership  ::  Legal