Diversification in ancient tadpole shrimps challenges the term 'living fossil'

Tuesday, April 2, 2013

The term 'living fossil' has a controversial history. For decades, scientists have argued about its usefulness as it appears to suggest that some organisms have stopped evolving. New research has now investigated the origin of tadpole shrimps, a group commonly regarded as 'living fossils' which includes the familiar Triops. The research reveals that living species of tadpole shrimp are much younger than the fossils they so much resemble, calling into question the term 'living fossil'.

Darwin informally introduced the term 'living fossil' in On the Origin of Species when talking about the platypus and lungfish, groups that appear to have diversified little and appear not to have changed over millions of years. For him living fossils were odd remnants of formerly more diverse groups, and suggestive of a connection between different extant groups. Ever since, the term has been widely used to describe organisms such as the coelacanth, the horseshoe crab and the ginkgo tree. The term has been controversial, as it appears to suggest that evolution has stopped altogether for these organisms, and some scientists have argued that it should be abandoned.

Tadpole shrimps are a small group of ancient crustaceans (a group which includes the familiar Triops) that are often called 'living fossils', because the living species look virtually identical to fossils older than the dinosaurs. Analysing DNA sequences of all known tadpole shrimps, and using fossils from related crustacean groups ? such as the water flea and the brine shrimp ? the team of researchers, from the University of Hull, University of Leicester and the Natural History Museum in London, showed that tadpole shrimps have in fact undergone several periods of radiation and extinction.

Different species of tadpole shrimp often look very similar (they are called 'cryptic species'), and so it is only with the advent of DNA sequencing that scientists have realized that they are a surprisingly diverse group. The team's results uncovered a total of 38 species, many of them still undescribed. This abundance of 'cryptic species' makes it very difficult for fossils to be assigned to any particular species as they all look remarkably similar. For example, 250-million-year-old fossils have been assigned to the living European species Triops cancriformis whereas the team's results indicate that the living T. cancriformis evolved less than 25 million years ago. First author Tom Mathers says "In groups like tadpole shrimps where cryptic speciation is common, the fossil record says very little about patterns of evolution and diversification and so the term 'living fossil' can be quite misleading. For this reason, we used fossils from related groups to gain an understanding about the evolution of tadpole shrimps".

The lead author Africa G?mez said, "Living fossils evolve like any other organism, they just happen to have a good body plan that has survived the test of time. A good analogy could be made with cars. For example the Mini has an old design that is still selling, but newly made Minis have electronic windows, GPS and airbags: in that sense, they are still 'evolving', they are not unchanged but most of the change has been 'under the hood' rather than external. By comparison, organisms labeled as 'living fossils' such as tadpole shrimps, are constantly fine-tuning their adaptation to their environment. Although outwardly they look very similar to tadpole shrimp fossils from the age of the dinosaurs, their DNA and reproductive strategies are relatively hidden features that are constantly evolving. The flexibility of their reproductive strategies, which our research has revealed, could be the evolutionary trick that has allowed them to persist as a morphologically conservative group for so long"

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The new study is published today in PeerJ, a new peer reviewed open access journal in which all articles are freely available to everyone (https://PeerJ.com).

PeerJ: http://https://peerj.com

Thanks to PeerJ for this article.

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Source: http://www.labspaces.net/127552/Diversification_in_ancient_tadpole_shrimps_challenges_the_term__living_fossil_

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'Transformers 4' takes shape with help from China

This undated publicity photos provided by courtesy of Paramount Pictures shows Bumblebee in a scene from the film, "Transformers: Dark of the Moon." (AP Photo/Courtesy Paramount Pictures)

This undated publicity photos provided by courtesy of Paramount Pictures shows Bumblebee in a scene from the film, "Transformers: Dark of the Moon." (AP Photo/Courtesy Paramount Pictures)

LOS ANGELES (AP) ? Michael Bay's "Transformers" robots are shaping up again with an assist from China.

Paramount Pictures announced a deal Tuesday with China Movie Channel and Jiaflix Enterprises to help on the production of "Transformers 4," the next installment in the director's blockbuster franchise.

According to the agreement, China Movie Channel, which is overseen by the Chinese government, will help select filming sites in China, and with theatrical promotion and possibly post-production work there.

It also will work with the filmmakers on casting Chinese actors in the movie, which stars Mark Wahlberg and is due out in June 2014.

Jiaflix, headed by former Academy of Motion Picture Arts and Sciences president Sid Ganis, brokered the deal. The company exports Chinese films to overseas markets and promotes production and distribution of films in China.

Bay's 2011 smash "Transformers: Dark of the Moon" took in $1.1 billion worldwide, including $165 million in China.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/4e67281c3f754d0696fbfdee0f3f1469/Article_2013-04-02-Film-Transformers-China/id-b22b38e25d0e4acb8ef539fe5765f643

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Afghan teenager fatally stabs U.S. soldier

KABUL, Afghanistan (AP) ? An Afghan teenager killed an American soldier in eastern Afghanistan by stabbing him in the neck while he played with a group of local children, officials said Monday.

The killing comes as the monthly U.S. death toll rose sharply in March to 14 with the start of the spring fighting season when the Taliban and other insurgents take advantage of improved weather to step up attacks.

Sgt. Michael Cable, 26, was guarding Afghan and U.S. officials meeting in a province near the border with Pakistan when the stabbing occurred last Wednesday, two senior U.S. officials said. They spoke on condition of anonymity because the investigation is ongoing.

The attack occurred after the soldiers had secured the area for the meeting, but one of the U.S. officials said the youth was not believed to have been a member of the Afghan security forces or in uniform so it was not being classified as an insider attack.

The official said the attacker was thought to be about 16 years old, but the age couldn't be verified.

The Afghan and American dignitaries were attending the swearing-in ceremony of Afghan Local Police in Shinwar district in Nangarhar province, senior district official Zalmai Khan said. Afghan Local Police, or ALP, recruits are drawn from villages and backed by the U.S. military.

The soldier was playing with a group of children outside when the attacker came from behind and stabbed him in the neck with a large knife, Khan said, adding the young man had escaped to nearby Pakistan.

Taliban spokesman Zabiullah Mujahid said the young man was acting independently when he killed the soldier but had joined the Islamic militant movement since fleeing the scene.

The Pentagon said in a statement last week that Cable, of Philpot, Ky., died from injuries sustained when his unit was attacked by enemy forces.

At least 14 U.S. soldiers died in March, compared with four in the previous two months, according to an Associated Press tally.

The number of American troops killed in Afghanistan has dropped sharply as international forces increasingly take a back seat while preparing to end their combat mission by the end of 2014. But they continue to face dangers ranging from roadside bombs to attacks by their Afghan counterparts or insurgents disguised as government forces.

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Associated Press writers Kimberly Dozier and Amir Shah contributed to this report.

Source: http://news.yahoo.com/afghan-teenager-fatally-stabs-us-soldier-105007454.html

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Research deciphers HIV attack plan: How AIDS virus grooms its assault team

Apr. 1, 2013 ? A new study by Los Alamos National Laboratory and University of Pennsylvania scientists defines previously unknown properties of transmitted HIV-1, the virus that causes AIDS. The viruses that successfully pass from a chronically infected person to a new individual are both remarkably resistant to a powerful initial human immune-response mechanism, and they are blanketed in a greater amount of envelope protein that helps them access and enter host cells.

These findings will help inform vaccine design and interpretation of vaccine trials, and provide new insights into the basic biology of viral/host dynamics of infection.

During the course of each AIDS infection, the HIV-1 virus evolves within the infected person to escape the host's natural immune response and adapt to the local environment within the infected individual. Because HIV evolves so rapidly and so extensively, each person acquires and harbors a complex, very diverse set of viruses that develops over the years of their infection. Yet when HIV is transmitted to a new person from their partner, typically only a single virus from the diverse set in the partner is transmitted to establish the new infection.

The key discoveries here are the specific features that distinguish those specific viruses which successfully move to the new host, compared with the myriad forms in the viral population present in a chronically infected individual.

"The viruses that make it through transmission barriers to infect a new person are particularly infectious and resilient," said Los Alamos National Laboratory scientist Bette Korber. "Through this study we now better understand the biology that defines that resilience."

The team set out to determine whether the viruses that were successfully transmitted to a new patient might share distinct biological properties relative to those typically isolated from people with long-term, chronic infection. To do this, the group at U Penn cloned a set of intact viruses from acute infection, and a set of viruses from chronically infected people, and characterized them by measuring quantities that might be related to the virus's ability to successfully establish a new infection. They discovered several clear correlations. For example, transmitted viruses were both more infectious and contained more protective "envelope" per virus; envelope is the protein the virus uses to enter host cells.

The team identified an additional interesting property that could be a general characteristic of new viral infections: the transmitted HIV was capable of replicating and growing well in the presence of alpha interferon. Alpha interferon production is part of our innate human immune response to a new infection. As soon as a new viral infection is initiated in our bodies, local immune cells at the site of infection start secreting molecules called cytokines that have general antiviral activity and can inhibit the production of the newly infected virus. Alpha interferon is one of these potent cytokines.

In the early days of an HIV infection, this innate immune response increases to an intense level, called a "cytokine storm," which gradually recedes during infection. For a newly transmitted HIV to successfully establish infection, it must grow and expand in the new host while facing this cytokine storm. Although typical chronic viruses are sensitive to and inhibited by alpha interferon, transmitted HIV-1 viruses grew well in the presence of interferon.

Los Alamos scientists Elena Giorgi, James Theiler and Bette Korber were part of the analysis team working closely with investigators at the University of Pennsylvania, Nick Parrish and Beatrice Hahn. The paper, "Phenotypic properties of transmitted founder HIV-1" is in this week's issue of Proceedings of the National Academy of Sciences.

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The above story is reprinted from materials provided by DOE/Los Alamos National Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. N. F. Parrish, F. Gao, H. Li, E. E. Giorgi, H. J. Barbian, E. H. Parrish, L. Zajic, S. S. Iyer, J. M. Decker, A. Kumar, B. Hora, A. Berg, F. Cai, J. Hopper, T. N. Denny, H. Ding, C. Ochsenbauer, J. C. Kappes, R. P. Galimidi, A. P. West, P. J. Bjorkman, C. B. Wilen, R. W. Doms, M. O'Brien, N. Bhardwaj, P. Borrow, B. F. Haynes, M. Muldoon, J. P. Theiler, B. Korber, G. M. Shaw, B. H. Hahn. Phenotypic properties of transmitted founder HIV-1. Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1304288110

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_health/~3/N3tNW197Jd4/130401132056.htm

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Crude oil leaks in Arkansas suburb after ExxonMobil pipeline ruptures

Isolde Raftery , NBC News ? ? ? 6 hrs.

An ExxonMobil pipeline rupture near Little Rock, Ark., Friday evening has resulted in a ?major oil spill,? according to the Environmental Protection Agency -- and ignited further debate over the transportation of crude oil in the U.S.

Up to 10,000 barrels sprang from the pipeline, according to an incident report filed to the National Response Center by ExxonMobil early Saturday morning. Twenty-two residents were evacuated from their homes, according to a statement on the ExxonMobil website.

Mayflower, Ark., Chief of Police Bob Satkowski told Channel 7 News in Little Rock that those residents had to leave their homes because of health risks from the crude oil fumes and possible fires.

In a statement on the company website, ExxonMobil downplayed the environmental concerns, saying that the air quality doesn?t likely present a human health risk, ?with the exception of high-pooling areas.?

KARK, an NBC affiliate station in Little Rock, reported that part of the pipeline runs through a water source that provides drinking water to nearly 400,000 residents in central Arkansas. The 20-inch wide pipeline goes through Lake Maumelle.

The pipeline, officially known as the Pegasus pipeline, transports heavy Canadian crude oil from Patoka, Ill. down to the Sunoco Logistics Nederland terminal in Texas, which feeds into Houston area refiners, according to the Exxon website. The pipeline, which can carry more than 90,000 barrels a day, was stopped Friday. ExxonMobil did not say when it would reopen.

EPA officials said the cleanup would be long and expensive, according to KARK. It was not reported who would pay for the cleanup.

The leak was first reported at 5 p.m. Friday, when someone called the National Response Center to report a drop in pipeline pressure.

Two hours later, a caller reported that there was a ?significant amount of material release.? The caller said the oil leak lasted about three hours.

An updated report early Saturday said up to 10,000 barrels were discharged and that the product had been released ?into flume pipes and into a pond, a tributary of Lake Conway.?

Friday?s spill prompted immediate response from critics of the proposed Keystone XL pipeline, which would transport about 800,000 barrels per day of Canadian crude oil to the Gulf Coast for refining.

Massachusetts Rep. Ed Markey took to Facebook to lash out against Canadian crude oil.

?This latest pipeline incident is a troubling reminder that oil companies still have not proven that they can safely transport Canadian tar sands oil across the United States without creating risks to our citizens and our environment,? Markey said. He is the top Democrat on the Natural Resources Committee.

?Tar sands oil is already the dirtiest, riskiest oil around, and should not be getting a free ride across America,? he continued. ?It?s time that we recognize the real effects producing and burning this oil will have on our climate, and the real world damage it can cause when it is spilled in our neighborhoods.?

This has been a bad week for crude oil public relations. On Wednesday, according to Reuters, a train carrying crude oil derailed in Minnesota and spilled up to 30,000 gallons.

Last week, the Pipeline and Hazardous Materials Safety Administration recommended fining ExxonMobil Pipeline Company $1.7 million for how the company responded to a crude oil pipeline failure in the Yellowstone River in Montana.

The Mayflower spill may be 10 times more significant than the Montana spill, which leaked 1,509 barrels.

The 1989 Exxon Valdez spill poured 260,000 to 750,000 gallons into Alaskan waters.

These spills pale in comparison, however,to the 2010 Deep Water Horizon oil spill, the most significant oil spill in the U.S., which leaked 4.9 million barrels into the Gulf Coast.

Reuters contributed reporting.

Source: http://feeds.nbcnews.com/c/35002/f/653381/s/2a30ca54/l/0L0Snbcnews0N0Cbusiness0Ccrude0Eoil0Eleaks0Earkansas0Esuburb0Eafter0Eexxonmobil0Epipeline0Eruptures0E1C91550A11/story01.htm

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The case against offering perfect-attendance awards ? Business ...

Absenteeism is an issue that affects all employers, all year long. How do you motivate employees to cut down on absenteeism? Offering perfect-attendance awards may not be the right carrot. Here?s why.

1. It won?t motivate the employees who feel that achieving perfect attendance is too lofty of a goal. You?ll likely find that it?s the same employees getting the award; the others won?t care and won?t bother.
2. It?ll drive some employees to get to work no matter what?no matter that they have the flu and wind up infecting others who then have to take sick days.
3. It punishes non-abusers. Theo??reti??cally, an attendance award is supposed to motivate those with poor attendance who see nothing wrong with calling out ?sick? in order to recover at the mall, a casino, or the beach. However, you?ll wind up having to take the award away from an employee who has a great attendance record, but then has the bad luck of having his or her car break down one day.
4. The award must be just right. Too large?see No. 2. Too small?see No. 1. Giving extra time off is counter to the goal of the award, which is having employees at work.
5. Watch the Family and Medical Leave Act. You know you cannot count FMLA absences against em??ployees. But does the employee who misses out on the award due to a one-day absence for a family emergency and sees a co-worker receive the award despite being out for weeks at a time? You can explain the law all you want, but the em??ployee will likely still be demotivated when comparing attendance records.
6. Beware of how you define ?perfect.? It should never include legally protected time off, such as jury duty. You also don?t want to discourage employees from using vacation time because it sends the message that your company doesn?t respect employees? need to relax and recharge.

What to do instead

Should you really reward employees for doing what?s expected of them: showing up for work on time every day?

Treating absenteeism like the disciplinary issue it is may be more effective at curbing abuse. Follow your company?s discipline policy when employees violate the attendance policy. Rate attendance, reliability, and/or dependability on performance appraisals.

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Jeremy Renner Has a New Baby Girl!

Source: http://www.thehollywoodgossip.com/2013/03/jeremy-renner-has-a-new-baby-girl/

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