Long-suspected cause of blindness from eye disease disproved

Mar. 11, 2013 ? Vision scientists long have thought that lack of very long chain fatty acids in photoreceptor cells caused blindness in children with Stargardt type 3 retinal degeneration, an incurable eye disease. But researchers at the University of Utah's John A. Moran Eye Center have shown in a new study that lack of these fatty acids does not cause blindness, meaning that the search for the mechanism that robs children of their sight must start anew.

Researchers led by David Krizaj, Ph.D., associate professor of ophthalmology and visual sciences at the Moran Eye Center, bred mice that lacked fatty acids in their photoreceptor cells and to their surprise found that the mice's eyesight was normal. "There was no defect in their daytime or nighttime vision," Krizaj says. "The lack of very long chain fatty acids does not appear to compromise vision in itself."

The research was published March 11, 2013, in PNAS online. Peter Barabas, Ph.D., a postdoctoral fellow at the Moran Eye Center, is first author on the study.

Stargardt disease is a form of macular degeneration that strikes about one in 10,000 children between the ages of 6 and 20. There is no treatment for the disease, although there is evidence that nutrition supplements and protecting eyes from UV rays might be beneficial in slowing the progression of blindness.

There are three types of Stargardt disease caused by three different gene mutations. (Paul Bernstein, M.D., Ph.D., professor of ophthalmology and visual sciences and a co-author in the PNAS study, discovered one of the mutations in a Utah family.) Type 3, a rare dominant form of Stargardt disease, is caused by a mutation in ELOVL4, a gene that encodes an enzyme that helps to make fatty acids obtained through our diet into forms that can be incorporated into cell membranes. The mutation displaces the enzyme from its location in the cell's network of tubules and sacs, called the endoplasmic reticulum, into cellular liquid known as cytosol, which blocks the synthesizing of very long chain fatty acids in photoreceptor cells. But proving that the lack of these fatty acids actually causes blindness has been difficult to show in experiments because mice in which ELOVL4 was knocked out did not survive.

Krizaj and his colleagues overcame that problem by engineering mouse models that lacked ELOVL4 only in their photoreceptor cells, allowing the mice to survive but with the fatty acids in those cells reduced up to 90 percent. This allowed the researchers to test directly whether loss of very long chain fatty acids replicates vision loss observed in children with Stargardt's disease. As they report in the journal, electrophysiological and behavioral testing of daytime and night vision in genetically engineered mice showed that sight was not affected despite the dramatic reduction in very long chain fatty acids in photoreceptor cells.

Researchers now must look for a different cause of Stargardt type 3. "If it's not the loss of fatty acids causing the disease, then we'll have to find other strategies to help these kids," Krizaj says.

One possibility is that mutated proteins escaping from the endoplasmic reticulum are aggregating in the cytoplasm, a jelly-like substance in the cell, and resulting in large deposits of mutated and normal proteins. "This is almost like causing photoreceptor cell death by blocking intracellular traffic and clogging the cells' drains," Krizaj says.

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Story Source:

The above story is reprinted from materials provided by University of Utah Health Sciences.

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. P. Barabas, A. Liu, W. Xing, C.-K. Chen, Z. Tong, C. B. Watt, B. W. Jones, P. S. Bernstein, D. Krizaj. Role of ELOVL4 and very long-chain polyunsaturated fatty acids in mouse models of Stargardt type 3 retinal degeneration. Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1214707110

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/vPkH3ksYuhw/130311173349.htm

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Top House tax lawmaker trains sights on small businesses

By Kim Dixon

WASHINGTON (Reuters) - The top tax law writer in the House of Representatives will pitch a plan to revamp the taxation of many small businesses, and some large ones, on Tuesday in his latest bid to rewrite the tax code.

Dave Camp, chairman of the House Ways and Means Committee, has said he wants to pass tax reform legislation this year. But the Michigan Republican faces an uphill climb with his party and the Democrats deeply split on tax-and-spending policies.

Camp's plan, not yet released, will seek to overhaul small business taxes, but also cover businesses not organized as traditional corporations, often known as "pass-throughs."

These businesses include structures such as partnerships, in which profits are not retained by the business or distributed to corporate shareholders, but rather, are passed through to the partners, who are taxed on that income. The top income tax rate since the beginning of the year is 39.6 percent.

That is higher, by contrast, than the top corporate income tax rate of 35 percent, though many large corporations do not pay that rate thanks to tax breaks for selected industries.

Pass-throughs range from Mom-and-Pop storefronts to global hedge funds and law firms. About 53 percent of the $1.3 trillion in total business income in this category will be reported in 2013 on returns of taxpayers earning at least $200,000, according to the nonpartisan congressional Joint Committee on Taxation.

The two parties have sparred over small business taxes. Republicans steadfastly oppose higher rates on wealthier individuals, whom Republicans call job creators. Obama and most other Democrats repeatedly have proposed raising the top tax rates paid by the wealthy.

The Democrats won a key round in this fight in January with a deal ending the "fiscal cliff" stand-off that raised the top tax rate on individual income above $400,000.

Democrats want more new tax revenue, presenting a major hurdle to fundamental tax reform, given Republicans' opposition to this, as highlighted in comments by Camp's Republican counterpart in the Senate on Monday.

"It has become more and more common for my friends on the other side of the aisle to argue in favor of simply eliminating so-called tax loopholes in order to raise revenue, and then calling that process quote-unquote tax reform," Orrin Hatch, the top Republican on the Senate Finance Committee said on the Senate floor.

The top Democratic taxwriter, Senator Max Baucus, is also pitching tax reform, but has had disagreements with Senate leaders over the details.

Camp's draft is likely to include some non-controversial measures, like making permanent a tax break for writing down the cost of equipment for certain business.

The Obama administration has floated the idea of forcing large businesses now taxed as pass-throughs to file as corporations instead, something Republicans have resisted.

(This story corrects Camp's home state in paragraph 2)

(Reporting by Kim Dixon; Editing by Leslie Gevirtz)

Source: http://news.yahoo.com/top-house-tax-lawmaker-trains-sights-small-businesses-222330821--business.html

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Senate immigration group: National ID too costly

WASHINGTON (AP) ? Senators working on a sweeping immigration bill will likely abandon the idea of a new high-tech ID card for workers because it's too expensive, a key negotiator said.

That means their emerging legislation, which they've promised will crack down on employers who hire illegal immigrants, likely will seek to expand a little-used system criticized as error-prone and vulnerable to fraud that employers can use to check the legal status of workers, mainly using Social Security numbers.

The system, called E-Verify, is now purely voluntary, and officials with labor and immigrants' rights groups say it would have to be greatly improved before being required nationally.

Sens. Lindsey Graham, R-S.C., and Chuck Schumer, D-N.Y., members of the bipartisan Senate immigration negotiating group, had championed creation of a biometric ID card instead that would use personal markers such as fingerprints to make it easy for employers to check the status of prospective hires. But Graham said cost estimates came back higher than he expected.

"That seems to have been cost-prohibitive, so we're looking at other ways to achieve the same goal," Graham told reporters this week at the Capitol.

Graham said no final decision had been made on ditching the biometric ID card idea, which had also sparked civil liberties concerns, and he declined to say how much such a card would cost. A study by the University of California, Berkeley Law School's Warren Institute last year estimated start-up costs to the government for such a program would top $22 billion.

For Graham, Schumer and the other six senators trying to finalize an immigration bill by next month, a workable employer verification system is fundamental to legislation that also would secure the border, improve legal immigration and provide eventual citizenship to the estimated 11 million illegal immigrants already here. The immigration bill signed by President Ronald Reagan in 1986 is often criticized because it legalized nearly 3 million people while offering assurances that employers would have to verify the legal status of workers, but included no real mechanisms to ensure that happened.

Graham said that no amount of border enforcement would stop the flow of illegal immigrants without measures to keep employers from hiring them.

"If you don't control who gets a job, it doesn't matter how high the fence is," Graham said. "The best virtual fence is an employer verification system."

E-Verify was launched as a pilot program in 1997 and now is used by about 7 percent of employers. It's largely voluntary as a federal program but mandatory in some states. Draft immigration legislation by President Barack Obama, which he has said he'll offer if the Senate group doesn't come to agreement quickly enough, would make E-Verify mandatory nationally, and the Senate group is likely to take the same route.

E-Verify allows employers to electronically submit prospective workers' Social Security numbers or other information to be checked against government databases. Critics say it's error-prone because of mistakes in government records and that it has no reliable way to catch someone who is using a fraudulent Social Security number. Immigrants' rights groups also complain that workers can't easily contest disqualifications and that employers have been known to misuse the program by threatening to run workers through E-Verify if they try to organize a union.

The federal Citizenship and Immigration Services, which helps administer the program, says it's gotten progressively easier to use and more accurate.

"Improving the accuracy of the E-Verify system remains our primary goal," Soraya Correa, an associated director at the agency, told a House hearing last month.

But because of how hard it is for a worker to contest a disqualification, critics say any error rate is too high.

"The error rate is low but when applied to the entire American workforce, every workplace in the U.S., that's a problem," said Emily Tulli, an attorney at the National Immigration Law Center. "Only 7 percent of employers are currently utilizing it so if you think about taking that utilization from 7 percent to 93 percent more, it is problematic."

The U.S. Chamber of Commerce opposed E-Verify for years as cumbersome and unwieldy, but recently decided to support it as long as certain protections are in place for businesses. Randy Johnson, the Chamber's senior vice president for labor, immigration and employee benefits, said the program has improved, and for businesses, it's a reasonable price to pay as part of an overall immigration overhaul. Business supports an immigration overhaul in part because it would ensure a reliable workforce.

Businesses "see this E-Verify system as a necessary slice of the pie to move comprehensive immigration reform forward," Johnson said.

If they do expand E-Verify, senators are expected to endorse ways to make it more reliable and better at detecting ID fraud, such as by expanding the use of photo IDs in the system. For many lawmakers, especially Republicans skeptical of immigration legislation, an airtight employer verification system will be necessary for them to be able to support the bill.

But critics are skeptical that any changes would make the program acceptable.

"The system is still too error-prone," said Chris Calabrese, an attorney at the American Civil Liberties Union. "It will prevent lawfully present Americans from being able to work."

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/89ae8247abe8493fae24405546e9a1aa/Article_2013-03-12-Immigration-Employers/id-6f94ad76161e4c3489222a4058909df6

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Source: http://www.thehollywoodgossip.com/2013/03/who-will-be-the-next-pope/

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Lunar impacts created seas of molten rock

Mar. 11, 2013 ? A new analysis of data from NASA's Lunar Orbiter Laser Altimeter (LOLA) shows that molten rock may have been present on the Moon more recently and for longer periods than previously thought. Differentiation -- a settling out of rock layers as liquid rock cools -- would require thousands of years and a fluid rock sea at least six miles deep.

Early in the Moon's history an ocean of molten rock covered its entire surface. As that lunar magma ocean cooled over millions of years, it differentiated to form the Moon's crust and mantle. But according to a new analysis by planetary scientists from Brown University, this wasn't the last time the Moon's surface was melted on a massive scale.

The research, led by graduate student William Vaughan, shows that the impact event that formed the Orientale basin on the Moon's western edge and far side produced a sea of melted rock 220 miles across and at least six miles deep. Similar seas of impact melt were probably present at various times in at least 30 other large impact basins on the Moon.

The research is published in the April issue of the journal Icarus.

Vaughan and his colleagues show that as these melt seas cooled, they differentiated in a way that was similar to the lunar magma ocean. As a result, rocks formed in melt seas could be mistaken for "pristine" rocks formed very early in the Moon's history, the researchers say.

"This work adds the concept of impact melt magma seas to the lexicon of lunar rock-forming processes," said planetary geologist James W. Head III, the Scherck Distinguished Professor of Geological Sciences and the senior researcher involved in the study. "It emphasizes that one must consider the detailed point of origin of the rocks in order to interpret them correctly."

That includes rocks brought back during the Apollo program and Russia's Luna missions. It's quite possible, the researchers say, that impact melt material is present in lunar samples thought to be representative of the early formation of the lunar crust. The amount of rock formed in melt seas is far from trivial. Vaughan and his colleagues estimate that impacts forming the Moon's 30 large basins produced 100 million cubic kilometers of melt, enough to make up 5 percent of the Moon's crust.

If lunar samples do include melt material, it would help to explain some puzzling findings from lunar samples. For example, in 2011 an analysis of a sample assumed to have originated in the early lunar crust suggested that the sample was 200 million years younger than the estimated time when the lunar magma ocean solidified. That led some researchers to conclude either that the Moon is younger than previously estimated or that the lunar magma ocean theory was flawed. But if that sample actually originated from a melt sea, its young age could be explained without rewriting the history of the Moon.

The melt sea at Orientale

The Orientale basin is only partly visible from Earth on the western edge of the Moon's near side. Because it's one of the few basins on the Moon that hasn't filled in with volcanic basalt, it provides a great place to investigate the geology of melt seas and to test whether they differentiate as they cool.

For the Orientale melt sea to have differentiated, it must have been liquid for a long time -- thousands of years. To be liquid that long, it must have been quite thick. That left the researchers with a question that wasn't easy to answer: How thick was the Orientale melt?

"In pictures, you're just seeing the top of an impact melt body, so we have to find a way to infer how thick it was," Vaughan said.

To do that, Vaughan and his colleagues took advantage of the fact that a liquid shrinks when it cools and solidifies. Data from the Lunar Orbiter Laser Altimeter (LOLA) showed that the sheet had subsided by about two kilometers from the surrounding rock, giving the researchers an idea of how much the sea shrank. With that data, they could calculate its volume and infer its depth.

According to the calculations, the Orientale melt sea must have been at least 10 kilometers thick. Far shallower melt sheets from impacts on Earth are known to have differentiated, so it's a safe bet that Orientale was thick enough to differentiate.

The next question was what that differentiation might look like. Based on the compositions of the lunar crust and mantle material melted, Vaughan could determine the composition of the impact melt sea. From there, he could make a model of what rocks would have formed as the melt sea cooled. According to the model, thick layers of rocks like dunite and pyroxenite form at the base of the melt sea from dense, early crystallizing minerals that sink through the melt. Other minerals float up through the melt to form layers of rocks such as norite at the top of the melt sea -- very similar to differentiation processes in the lunar magma ocean.

Vaughan's model is supported by remote sensing data from the Maunder crater, the remnant of an impact that excavated material from the melt sheet after it cooled. The data confirm a noritic composition at least four kilometers deep in the melt sheet.

Taken together, the findings suggest that impact melt seas produce rock in a way that's very similar to the lunar magma ocean. And that could help to clear up some lingering questions about the magma ocean paradigm.

"This is a mechanism by which the Moon was later modified to add petrologic complexity," Vaughan said. "It helps make sense of mineralogical data that doesn't always fit in this lunar magma ocean idea."

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The above story is reprinted from materials provided by Brown University.

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. William M. Vaughan, James W. Head, Lionel Wilson, Paul C. Hess. Geology and petrology of enormous volumes of impact melt on the Moon: A case study of the Orientale basin impact melt sea. Icarus, 2013; 223 (2): 749 DOI: 10.1016/j.icarus.2013.01.017

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

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/3YZ_LnhkiMc/130311151257.htm

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The Weirdest Thing on the Internet Tonight: Testaballoon

This machinima-style CGI short illustrates that you can't just float through life, even if you do have a balloon for a head. Produced by Valerio Spinelli of studio Pixel Pongo, Testaballoon follows the trials of a man whose head is far too light for his body. More »

Source: http://feeds.gawker.com/~r/gizmodo/full/~3/E_tfUYV1Zag/the-weirdest-thing-on-the-internet-tonight-testaballoon

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Blonde Cuties Alert! Hilary Duff & Luca Enjoy a Day Out!

Hilary and son Luca hit up a birthday party together! Plus, see more photos of celebs spending time with their loved ones!

Source: http://www.ivillage.com/star-snapshots-celebrity-kids-and-family-photos-2012/1-b-462723?dst=iv%3AiVillage%3Astar-snapshots-celebrity-kids-and-family-photos-2012-462723

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