Wednesday, May 7, 2008
May 6, 2008
Family Science Project Yields Surprising Data About a Siberian Lake
By CORNELIA DEAN
In 1945, when Stalin ruled the Soviet Union, Mikhail M. Kozhov began keeping track of what was happening under the surface of Lake Baikal, the ancient Siberian lake that is the deepest and largest body of fresh water on earth.
Every week to 10 days, by boat in summer and over the ice in winter, he crossed the lake to a spot about a mile and a half from Bolshie Koty, a small village in the piney woods on Baikal’s northwest shore. There, Dr. Kozhov, a professor at Irkutsk State University, would record water temperature and clarity and track the plant and animal plankton species as deep as 2,400 feet.
Soon his daughter Olga M. Kozhova began assisting him and, eventually her daughter, Lyubov Izmesteva, joined the project. They kept at it over the years, producing an extraordinary record of the lake and its health.
Now Dr. Izmesteva and scientists in the United States have analyzed the data and concluded, to their surprise, that the water in Lake Baikal is rapidly warming. As a result, its highly unusual food web is reorganizing, as warmer water species of plankton become more prevalent. These shifts at the bottom of the food web could have important implications for all of the creatures that live in the lake, they say.
Although Dr. Kozhov is famous among scientists who study lakes — his 1961 book “Lake Baikal and Its Life” is considered a classic — the new report is “the international debut of the Kozhov family’s legacy of research,” Stephanie E. Hampton of the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara, said in an e-mail message.
She led the work along with Dr. Izmesteva who, like her mother and grandfather before her, is a professor at the university and a researcher at the biological field station it established in Bolshie Koty in 1918. Their findings are being reported this month in the journal Global Change Biology.
Like others who have seen the data, Dr. Hampton said in an interview that she was in awe of the people who had collected it. “Even in the spring, summer and fall, this is tough,” she said. “In the winter to go out a mile and a half on the ice and break through it to take water samples, in a year-round effort for 60 years, is pretty amazing to me. Every time I think about it I am humbled.”
Marianne V. Moore, an ecologist at Wellesley College and another researcher on the project, said she learned about the data in 2001 when she took students in her class, “Baikal and the Soul of Siberia,” to the lake. Dr. Izmesteva spoke to the group and showed a few slides, which the translator said had been drawn from a 60-year record. “I thought he had made a mistake,” Dr. Moore recalled. “So I basically ignored it.”
When she returned with another class two years later and another scientist mentioned the data, “my jaw dropped to the floor,” she said. “I realized this is just extraordinary.”
She got in touch with Dr. Hamilton, who is an expert in the analysis of complex ecological field data, particularly the use of statistical techniques to discern real trends in the messy ups and downs of nature. The center in Santa Barbara financed the collaboration.
Baikal is a place of unusual biodiversity, with many species found nowhere else. Among them are giant shrimp, bright green sponges that grow in shallow water forests and the Baikal seal, the world’s only exclusively freshwater seal. In 1996, the United Nations Educational, Scientific and Cultural Organization, or Unesco, designated the lake a World Heritage Site.
Although it is known that warming is more intense at high latitudes, as in the Baikal area, and that water is warming in other major lakes, including Lake Tahoe in Nevada and Lake Tanganyika in central Africa, many scientists had thought that Lake Baikal’s enormous volume and unusual water circulation patterns would buffer the effects of global warming.
Instead, the researchers report, surface waters in Lake Baikal are warming quickly, on average by about 0.4 degrees Fahrenheit every decade. At a depth of about 75 feet, the increase is about 0.2 degrees per decade, they say, enough to jeopardize species “unable to adapt evolutionarily or behaviorally.”
Over the last 137 years, the researchers say, the ice-free season has lengthened by more than two weeks, primarily because ice forms later in the year. The database, including data on chlorophyll that the family started collecting in 1979, suggest that the “growing season” for plankton and algae has lengthened in the lake. Chlorophyll levels have tripled since measurement began, the researchers said.
Ordinarily, the researchers said in their report, this increased plant growth would be accompanied by decreases in water clarity, but that is not what the data show at Lake Baikal. This finding, they said, “highlights the importance of establishing monitoring for ‘early warming’ before a need for monitoring may be perceived visually.”
Now, Dr. Hampton said, she and other researchers are examining how the Kozhov family’s data fit with records of ecological phenomena elsewhere. So far, she said, “the data correlate well.”
“You could not make up something like this.” she added.
Dr. Moore said Dr. Kozhov died in 1968 and his daughter Olga died in 2000. The family persisted in their work through years of political, economic and social turmoil, especially the collapse of the Soviet Union after the fall of the Berlin Wall in 1989 when, Dr. Moore said, “funds for the program just dried up.”
Today, she said, Dr. Izmesteva and her colleagues pay for their work in part with fees they earn by consulting or doing environmental impact assessments.
“They sustain the program any way they can,” Dr. Moore said.
Tuesday, May 6, 2008
Continental Airlines CEO Larry Kellner bet business on being on time, and won
A View from the Top by leader of one of most successful turnarounds in U.S. aviation transportation history
BY APRIL NEILSON
* Printable Version
In an industry known for stiff competition, market volatility and demanding customers, Larry Kellner has a formula guaranteed to smooth out the ride.
Speaking to a packed audience of students and faculty Oct. 11 at the Graduate School of Business, the Continental Airlines Inc. chairman and CEO gave excerpts from his leadership playbook that led to one of the most successful turnarounds in U.S. aviation transportation history.
Credited with taking Continental from bankruptcy to the world's fourth-largest airline, Kellner engaged his audience in a lively tour behind the scenes of the highly competitive and tumultuous airline business—to provide a view of some of the planning processes that earned this company its present day success. His speech was part of the student-run "View from the Top" speaker series, which brings executives to the school to discuss their experiences and leadership styles.
When Kellner became the CFO of Continental in 1995, the carrier was ranked the nation's worst airline in terms of customer complaints, lost baggage and on-time arrivals. "It was a pretty broken company," Kellner said. "And it wasn't just a one-off problem. This was the culture of 'How can we make it cheaper? How can we do it with less?' And we were lousy …, getting tons of complaints. We were losing bags because we were late, and late because we were losing bags."
Confronting $2.3 billion in debt defaults, no cash and a third potential bankruptcy, Kellner came up with a turnaround plan that defied conventional wisdom and some of the standard operating practices of the times. "If you don't spend any money you're not going to make it," he said. The number one priority: Bring flights in on time. "We needed to tell [our employees] that was the most important thing they do, and to put incentives behind it." The decision: For every month the company made it to the top five for on-time arrivals, employees would earn an additional $65.
Within 30 days, Continental moved up to fourth place for on-time arrivals, and within two months, gained the number one slot—a ranking it holds today. "All of a sudden the employees who had been ripping the Continental patches off their uniforms when they went to Wal-Mart after work were in the company store buying Continental hats," Kellner said.
Continental's "Go Forward" plan gave employees more ownership in the firm 's success and more transparency about how the company was run. "If you want to be successful in any business, you need a plan that tells you where you're going. You've got to communicate the plan. … And you've got to treat people with respect and dignity."
Continental's mission was simple—summed up in four key elements:
# An operating plan that "makes reliability a reality";
# A financial plan that "funds the future";
# A people plan that encourages and supports "working together"; and
# A marketing plan delivering a "fly-to-win" strategy.
Kellner said: "You have to understand what it is you want to do. If the plane is there waiting at the gate but the Jetway is not attached, you're not there yet. You can't get the door open."
In a business where every minute counts, it is important, he says, that when you've been on a long flight, in a small seat, you don't sit for 10 minutes waiting for the Jetway to arrive to disembark. "My job is to keep our employees happy and focused on a business plan that works. If they keep you happy … our shareholders will be happy," he said.
Since Kellner joined the carrier, Continental has won more awards for customer satisfaction than any other airline. Having survived two bankruptcies, the aftermath of the Sept. 11, 2001, terrorist attacks, the second Gulf War and spiraling fuel costs, Continental's strategy—under Kellner's leadership—continues to pay off.
Kellner himself is a three-time winner of CFO Magazine's CFO Excellence Award. Says Kellner, "You've got to constantly reinvent the business, reinvent the way you do it, and keep your product fresh. I fly our competitors on a regular basis—I want to see what they are doing, how they are rolling out their service, what we can take from them. I will gladly take anything anyone does that's smarter."
April Neilson is a freelance writer.
Monday, May 5, 2008
Sunday, May 4, 2008
Exercise and Heart Rate
Author: Stan Reents, PharmD
Posted: 5/6/2007 10:02:03 AM
Many people know that monitoring their heart rate during exercise helps them determine how hard they are working. And others know that exercising at an intensity that keeps their heart rate in a specific range will result in a "training" effect.
But, recently, new research has revealed other ways you can use your heart rate to determine not only how hard you are exercising, but, also how healthy your cardiovascular system is. This review will discuss 4 different ways you can use your heart rate to monitor your fitness. Your personal trainer may not even know some of these details.
MAXIMUM HEART RATE
Before you can calculate your "target exercise heart rate," you first need to determine your "maximum heart rate".
The traditional formula for calculating maximum heart rate is:
- Max HR = 220 - age
However, several years ago, researchers in the department of kinesiology and applied physiology at the University of Colorado in Boulder noticed that this formula underestimated exercise heart rates in older subjects.
Hirofumi Tanaka, PhD, and his group conducted an exhaustive review of 351 studies involving nearly 19,000 subjects and derived a new formula. They then validated the new formula in 514 healthy subjects.
The formula they propose is:
- Max HR = 208 - (age x 0.7)
In 40-year-old subjects, both formulas yield the same result (ie., 180 beats per minute). However, the Tanaka equation produces slightly lower limits (than the old formula) in subjects younger than 40, and raises the limit slightly in subjects older than 40 years old.
Other formulas exist. What's important is that, for the elderly, and people who are not in shape, maximum heart rate should be determined by calculation since it would be too risky for these people to submit themselves to an all-out exercise test.
Determining Maximum HR From An All-Out Run:
The November 2004 issue of Runner's World magazine offers a method for fit runners to determine their maximum heart rate:
- run as hard as you can for 3 minutes
- walk for 2 minutes
- run as hard as you can for another 3 minutes
During the last minute of running, you should be at your maximum heart rate. NOTE: Do not do this unless you are fit, or have been given a clean bill of health by your physician.
But, let's say you're not interested in winning your age group in next month's neighborhood 10-K; you are only exercising for health reasons. In this case, you still need to know your maximum heart rate. This allows you to determine your "training" heart rate, which is explained below.
There's also a medical use for knowing maximum heart rate. Cardiologists have determined that the inability to attain a target heart rate during exercise appears to be an ominous predictor of mortality. Researchers at the Cleveland Clinic found that patients who could not reach at least 85% of their predicted exercise heart rate had a higher risk of death (Lauer MS, et al. 1999).
TRAINING HEART RATE
Now that you know your maximum heart rate, you can determine your training heart rate. Coaches and their athletes know that driving the heart rate up into a specific range is the key to improving performance in aerobic events like cycling, distance running, etc. For example, Ed Eyestone offers the following guidelines in the November 2004 issue of Runner's World magazine:
- 70-80% max HR: aerobic training pace
- 80-90% max HR: lactate threshold pace
- 90-97% max HR: long-interval pace
- 95-100% max HR: short-interval pace
Serious endurance athletes (triathletes, distance runners, etc.) will train mostly at the aerobic training pace. About 10% of their training will be at the lactate threshold pace. Extremely-intense "intervals" make up only a small percentage of the overall training plan.
Training heart rate is also helpful for people who want to exercise for health benefits. Research shows that untrained individuals will begin to improve their aerobic fitness when they exercise regularly at 50% of their maximum heart rate (Pollock ML, et al. 1998).
For example, for a 60-year-old person, the maximum heart rate (using the Tanaka equation) is 166. Fifty percent of that is 83 beats per minute. Thus, exercise does not need to be exhausting to achieve a health benefit.
RECOVERY HEART RATE
"Recovery" heart rate is a determination of how long it takes your heart rate to return to normal after you stop exercising. This concept is mostly for people who are out of shape. People with a slower recovery are at higher risk of sudden death than people who recover more quickly.
Researchers at the Cleveland Clinic exercised patients on a treadmill, then measured their heart rate 1 minute after running stopped and compared it to their peak heart rate. The failure of heart rate to fall rapidly after exercise stopped was associated with increased overall mortality (Cole CR, et al. 1999).
A similar result was seen in a study from France. Cardiologists exercised patients on a stationary bike for 10 minutes, then measured their heart rate 1 minute after cycling stopped and compared it to their peak heart rate. Patients with the poorest recovery had 2.1 times the risk of sudden death compared to patients with the best recovery (Jouven X, et al. 2005).
RESTING HEART RATE
And, finally, the 4th way you can use your heart rate to monitor your exercise program is to simply take your pulse while at rest. Resting heart rate is another indicator of your aerobic fitness.
One of the dramatic things that happens to your heart when you become aerobically fit is that your heart pumps more blood with each beat. This is known as "stroke volume". Since more blood is pumped with each beat, the heart doesn't need to beat as fast, so, resting heart rate is slower.
In one study of female runners, the resting heart rate directly related to how far the women ran per week (Williams PT. 1996):
|MILES RUN||RESTING HR|
You may have heard of marathon runners who have resting heart rates in the 50's, or, even in the 40's. Generally, this is a sign of a strong heart.
Unfortunately, the opposite is also true. In one study of middle-age men with no evidence of cardiovascular disease, a resting heart rate of 75 beats per minute or higher had 3.5 times the risk of sudden death compared to men with resting heart rates of less than 60 (Jouven X, et al. 2005).
So, it turns out that something as simple as keeping track of your heart rate can tell you a lot about your health and fitness. Here's how to do it:
•Resting Heart Rate: Take your pulse as soon as you wake up in the morning, preferably, without an alarm clock, and definitely before that first cup of coffee. Take it while you are still lying in bed; don't sit up. If you don't want to do a 60-second count, then do a 6-second count and simply add a zero.
•Maximum Heart Rate: This was discussed above. To repeat, do NOT do the running test unless you have a clean bill of health from your physician. Instead, use the formula by Tanaka et al. listed above.
•Training Heart Rate: If you simply want to exercise for health benefits, you only need to exercise at about 50-60% of your maximum heart rate. However, if you want to improve your times in a 10-K race for example, then you need to push your HR into the 70-90% range periodically. Since it is very difficult to take your pulse when you are exercising this hard, use a heart rate monitor.
Friday, May 2, 2008
Open Chain Versus Closed Chain Exercise
In addition to different types of muscle contraction, you can use two basic types of movement to elicit those contractions. Each has pros and cons, and you may need to analyze an activity to decide if you want to include it in your program. The names of these types of movement, open chain and closed chain, come from the science of biomechanics. They refer to whether or not the extremity is fixed at the distal end during an exercise, meaning whether the hand or foot stays in contact with either a stable surface or a piece of equipment that moves in a predetermined way. An open chain activity is one in which the extremity can move in any direction, because it is not attached at the end. For example, if you raise one of your feet off the ground, you can move that leg in any direction or sequence of movements. A closed chain activity, on the other hand, fixes the distal end of the extremity either to the ground or to a device that has a predetermined motion. When you keep your feet on the ground while you bend or straighten one joint, the other joints move in a predictable, set manner.
Open chain exercises do a good job of targeting one set of muscles for strengthening, but they increase the forces transmitted to the involved joint. Closed chain activities transmit less force to the joint (although they too can be stressful) and often are more functional movements. Another benefit is that when you perform closed chain exercises, you often strengthen several muscle groups.
Because of the increased stress on joints, keep open chain activities to a minimum. Exercises such as biceps curls are simple and usually do not cause too many problems. On the other hand, knee extension exercises that use an open chain motion produce a lot of stress to the knee and will probably increase your pain. If you opt for an open chain activity, keep the resistance lower around an arthritic joint. For example, you might do a knee extension in an open chain manner using rubber tubing, but keep away from knee extension machines. If you want to use a machine, the leg press is a better option; it is a closed chain activity and you can usually modify your position to further decrease the stress to your knees.