Knowing How You Hear May Help Interpret a Hearing Test ...

Understanding how the ear works may be helpful so that you can understand the results of your hearing test. The intricacies of the ear are amazing as is the process that takes place in order for an individual to finally get a message. There are three main steps that the sound goes through in order to give a message to the hearer.

You could get very philosophical when it comes to sound. The old question of whether a tree made a noise when it fell in the woods if no one was there to hear it is an example. Most people would agree that the tree did make a sound. The sound produced by the tree falling would produce a vibration. The rate at which the vibration would take place is called a frequency. The amplitude of that tree falling is how loud the sound was when it fell. It would have done this whether or not someone was there listening.

In order for someone to hear, a sound must first of all take place. Once a sound takes place it goes into the ear and causes the eardrum to vibrate.

From that initial step, the vibrations of the eardrum cause the middle ear bones to vibrate. At this point the sound gets louder and travels to the inner ear.

It is in the inner ear and onward that the most exciting intricacies of the ear take place. The Labyrinth of the inner ear has fluid in it. In that fluid area is the Cochlea. The cochlea is filled with tiny hairs called cilia. These hairs move as sound causes the fluid in the inner ear to move. The movement of the cilia causes a nerve impulse to the auditory nerve, which is where the final step in hearing takes place.

It is a very involved process. So you can see why there are a few reasons why a hearing test might be failed. The problem could be with the anatomy of the ear. There could be parts missing or malformations. You could have also damaged the ear. An individual could have too much fluid in the ear, or someone could be lacking in cilia that would also cause problems. Another scenario includes a problem with the auditory nerve. It could be missing, weakened, or paralyzed.

Having a hearing test is very important if you do not believe you hear as well as you should. After you have a full test, an audiologist should be able to explain to some degree what is going on with your ears. Further testing may also be necessary. Hopefully, knowing in advance how the ear works will help you to understand what is going on in your own ears.

Learn how well your hearing is. Find out more about Fresno, CA hearing test at: http://www.miracle-ear-fresno-visalia.com.

Source: http://www.articlesrx.com/knowing-how-you-hear-may-help-interpret-a-hearing-test/9932

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Retailers hope for last-minute Christmas surge

21 hrs.

CHICAGO/WHITE PLAINS, New York - Retailers limped into Christmas with last-minute blowout deals on everything from TVs to celebrity-branded clothing, after a disappointing few weeks of sales led many analysts to lower their expectations for the holiday season.?

Some industry watchers said shoppers were making smaller purchases, even though they are still visiting stores and browsing online. Since the holiday quarter can account for about 30 percent of annual sales and half of profit for many chains, such small distinctions can be crucial.?

"The attitude of the shopper went from Christmas euphoria on Thanksgiving weekend to more subdued, to less frenetic," said Thom Blischok, chief retail strategist and a senior executive adviser with consulting firm Booz & Company's retail practice.?

Before the season began, Blischok was looking for sales to rise more than 5 percent in November and December over the same period in 2011. Now, he said a gain of 2 percent to 2.5 percent appears more likely.?

Research firm ShopperTrak lowered its forecast last week for November and December sales. It is now calling for an increase of 2.5 percent, rather than 3.3 percent.?

"The season will be an OK season, it won't be as strong as last year but it won't be maybe as bad as feared heading into it," said Joseph Feldman, managing director and senior research analyst at Telsey Advisory Group. "Christmas comes every year."?

Some of those who are buying said they were holding back.?

Terene Collymore, a student of criminology at Monroe College in New Rochelle, New York, was at a Walmart on Monday, buying last-minute gifts, such as knitting supplies for her mother.?

Collymore said she was being more careful this year and not spending more on herself.?

"I don't throw money away," she said.?

Cheap TVs abound
Sales for the November-December holiday season are expected to rise 4.1 percent to $586.1 billion this year after a 5.6 percent increase in 2011, according to the National Retail Federation.?

But even with the diminished forecasts, retailers have done a good job controlling inventory levels this season, analysts said.?

The iPad mini has been tough to find in some places but is still available, while the new iPhone 5 is still in stock, suggesting that people may have stuck with their prior models or bought the less expensive iPhone 4S instead, said Feldman.?

The season has been "decent" but "not exceptional," said Noam Paransky, vice president in AlixPartners retail practice.?

He said he has not seen unplanned discounting or too much excess inventory despite slightly slower-than-expected growth.?

"Retailers have been disciplined. They haven't hit the panic button yet," Paransky said.?

Still, Target Corp slashed the price of its collaborative holiday collection with Neiman Marcus by 50 percent a few days ago. The collection was still marked at full price at Neiman Marcus.?

Meanwhile Sears was offering 60 percent off clothing from the reality TV family's "Kardashian Kollection," and Target, Walmart and Best Buy all had last-minute discounts hundreds of dollars deep on big-screen TVs.?

After-Christmas sales
Superstorm Sandy hit sales in the densely populated Northeast in late October and early November but retailers were able to bounce back weeks later with a strong turnout on Thanksgiving weekend.?

Now, fresh concerns about whether Washington will reach an agreement to avert the "fiscal cliff" of tax hikes and spending cuts before January 1 is leading some shoppers to curb spending.?

Overall, analysts said inventory levels appeared about right, though consumers' minds have changed since retailers placed orders for items such as apparel back in the spring.?

"I don't think it's an issue of ordering too much, I think it's the fact that the consumer has recognized 'I can learn to live with less, I don't have to have that fourteenth sweater, I just don't have to have it,'" said Blischok.?

Those retailers who are seeing weakness before the holiday could use after-Christmas sales to sell discounted goods, analysts said. Typically, retailers like to clear out their holiday merchandise quickly, so that shoppers coming in with the gift cards they received are more likely to buy full-price spring merchandise at fatter profit margins.?

Source: http://www.nbcnews.com/business/retailers-hope-last-minute-christmas-shoppers-bring-good-cheer-1C7661429

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cdabrands14: Alico Industries SC-NCH-M Scope LED New ...

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Source: http://cdabrands14.blogspot.com/2012/12/alico-industries-sc-nch-m-scope-led-new_23.html

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chometssylvain: ekbaresuja: kudals: Arts And Entertainment: Humor ...

Mid way through the week now and we?re still rolling on with plenty of content for you all. Did you miss out on anything? If so, jump on back a page and get caught up.. then once you?re done, join us in the Android Central forums for some more awesomeness. HTC Thunderbolt Forums ? Verizon [...]

Monday, July 16, 2012 Interview by Lon Woodbury David Brinkman, Founder and Director of Brinkman House, spoke to Lon Woodbury from strugglingteens.com on L.A. Talk Radio about a relatively new treatment option for at-risk teens called the Family Emerging Model. David and Melinda, his wife, have actually worked with a variety of boys between the [...]

By RACHEL COHEN AP Sports Writer Associated Press Sports updated 7:54 p.m. ET Nov. 17, 2011 The researchers studying a degenerative brain disease in former athletes plan to test about 100 retired NFL players to try to learn how to diagnose the condition during life. For now, the only way to confirm Chronic Traumatic Encephalopathy [...]

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BEIJING (AP) ? A Foxconn Technology Group employee jumped to his death Wednesday from a company-rented apartment building in southwest China?s Sichuan province, local police said. At least a dozen Foxconn employees have jumped to their deaths or tried to do so since 2010, casting spotlight on the world?s largest contract maker of electronics. The [...]

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Mark Cuban's Novel Income Tax Proposal Is The - Business Insider

Michael Seto

Typical economic policy is fairly straightforward: Spend more and cut taxes when the economy is weak. Hike taxes only when we've recovered.

During a Reddit Ask Me Anything session, billionaire Mark Cuban offered up a very contrarian take on taxes.

First, here was the question that keyed off his claim that taxes should rise on the rich, and that it wouldn't be that harmful to the economy.

Could you further explain your stance on taxes for businesses? I've seen where you said that taxes essentially don't matter for business. That entrepreneurs will still start a business because they don't say, "Wow, I have a great idea but the tax rate is too high." Still, wouldn't it be helpful to have lower taxes because when those entrepreneurs sell their business, they have more money left to fund other businesses? If I sell my business for $1MM and capital gains is 5% higher than it is now, that's $50K that I can't invest in startups. That's easily 5 less businesses that will have to find capital elsewhere.

And here's Cuban's answer (lightly edited for punctuation):

Like everyone else, I want taxes lower. More money = more choices. BUT, I believe in taking responsibility for the circumstances we find ourselves in. As a citizen I voted for a bunch of the idiots in office. When they were doing stupid shit, I stood by quietly. Even when I spoke up, it didn't impact anything.? So while I believe that lower taxes are good. I recognize that I was part of the problem. And given that we are in the middle of a big problem, what I believe is the optimal way doesn't matter.? What matters now is fixing the problem. Unfortunately the way to fix the problem is to have those who can pay more to pay more.? I've been proactive individually, I've written checks to the City of Dallas. I've written big checks for disasters where I know that anything not financed privately is going to come from taxpayers. So its my small way of trying to help. I think all these politicians who ignore the current context/realities of where we are, hurt more than help? If it were up to me, I would increase taxes and create metrics that triggered declines. If the unemployment rate falls to 6pct nationally and the Deb/t GDP ratio declines to a specified amount, we lower taxes. If it goes the other way, we increase them further on the wealthy. I could go on for days on ideas, but no one is listening to me. :)

This is a very businessy way of looking at taxes, that lower taxes are like a bonus for good times, and that in bad times people should take home less. That does make sense in a business. As a tax policy, it's pretty much the opposite of what every economist will argue.

That being said, on Twitter Conor Sen makes a good point, which is that this creates an incentive for the rich to actively care about the unemployment rate, and to promote policies which would get there. There may be a way to structure it so that it works out well for everyone.

Source: http://www.businessinsider.com/mark-cuban-unconventional-income-tax-proposal-is-the-exact-opposite-of-what-most-economists-believe-2012-12

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SCRAPBOOKING AND CHRISTMAS ? A MATCH MADE IN ...

Handmade cards are always extra special ? so why not show off your scrapbooking skills this Christmas with some beautiful and unique creations for friends and family?

Giving a handmade card is a wonderful way of expressing your personal thoughts and demonstrating to people how much they mean to you.? Card making is rewarding in more ways than one?you can save money too.

And you don?t have to be a scrapbooking expert either when it comes to card making.? ??There are thousands and thousands of websites with a huge range of ideas and illustrations for paper crafts and Christmas ideas, from the craft supplies stores to scrapbooking blogs ? and many of these also have really easy-to-follow tutorials demonstrating how to make cards etc.

Many of the craft store websites and scrapbooking blogs will also have templates for card-making to get you started.

For those who already do scrapbooking, making Christmas cards is a wonderful way of using up all those bits and pieces that you?ve accumulated during the year.? Don?t just think about patterned paper?you can use just about anything for card making and crafting?.lace, ribbon, felt, magazine cuttings, cotton wool, ice cream sticks, fabric scraps, stencils, glitter, marker pens, aluminium foil?the only limit is your imagination.

But don?t forget to match your card to an envelope before you get creative!

Card making can also be a fun way of entertaining kids after all the hullabaloo of Christmas is over?they can make their own ?thank you? cards from your craft supply box in appreciation of their gifts

So, with Christmas around the corner, don?t cut corners when it comes to spreading festive cheer and goodwill?jump online to the craft supply websites and start making your own personalised cards for friends and family to treasure.

Source: http://www.mylife-coach.net/6625/scrapbooking-and-christmas-a-match-made-in-heaven/

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jeetsingh: Winter Dining Round the Family Dining Table is back ...

With the winter approaching and the BBQ covered for the season there is a growing trend to return to family dining around a large dining table. Be it a lovely large formal dining table like Downton Abbey ?upstairs? .. or more like the antique farmhouse table ?below stairs? at Downton Abbey tastes vary but the principle is the same. Collective eating around a large dining table is back! With grandparents living longer there is an even greater need for dining tables to comfortably accommodate 4 to 6 people and yet be able to extend to a larger size when the generations gather.

Elisabeth James Antiques are the UK?s largest stockiest of original dining tables from Early Period, Georgian, Regency, Victorian and Edwardian periods. Under one roof we always have at least 100 tables in oak, mahogany and walnut. The range includes formal round tables to seat 6, 8 or 10 people, formal extending tables to seat 6 to 30 people and refectory or farmhouse tables to seat up to 16 people.

All of our stock is original and we select the best quality tables from estates and clearance to ensure that the restoration process produces the most stunning example from any period. Our in house team of restorers have specialised in finishing large dining tables for a combined 160 and use traditional techniques rather than the modern spray finishes most companies adopt today. Quite simply, whether a classic French polish, traditional wax finish or a hardy heat resistant lacquer, our team produce the most perfect finish of your choice. We supply the fine antiques trade and customers around the World with the very best quality at the lowest prices possible.

Amongst our antique dining tables and antique occasional tables our stock includes :-

17th, 18th and 19th Century oak refectory tables ? from 6ft to 14ft in length

Oak farmhouse tables ? from 6ft to 14ft in length

French farmhouse tables ? up to 13ft in length

Georgian mahogany pedestal tables ? from 8ft to 24ft in length

Regency mahogany pedestal tables ? from 8ft to 24ft in length

William IV extending tables ? from 8ft to 18ft in length

Victorian extending tables in mahogany, walnut and oak ? from 7ft to 20ft in length

Edwardian extending tables in mahogany, walnut and oak ? from 7ft to 16ft in length

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Antique Georgian breakfast table

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Victorian 19th century bamboo occasional table

Antique Victorian oval dining table

Elisabeth James Antiques is a family run business which allows the flexibility to manage all requirements 7 days a week and we offer home viewings in London and the Home Counties without obligation. Our warehouse is based just off junction 14 of the M1 so within easy reach from London in one hour.

Source: http://articlebro.com/2012/home-family/home-improvement/winter-dining-round-the-family-dining-table-is-back/

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Best Animal Videos Of 2012: The Cutest, Funniest And Most Popular Clips Of The Year

As 2012 comes to an end, it's a good time to reflect and remember the most important stories of the year. So let's be honest: wacky, cute and fascinating animal videos stole the show.

This was a particularly good year for animal watching: Viewers saw Siku the polar bear grow up on a live webcam, a monkey traipse through IKEA and sloth mania take the world by storm.

Cute pets were also a source of celebration here at The Huffington Post. If you want to take the aww-factor up a notch, check out our user-submitted Cutest Pets of 2012 slideshow.

Unfortunately, some of this year's animal stories left us little to smile at. Abuse at farms, horrific poaching and undercover trafficking were just a few of the issues surrounding animal welfare and conservation. As for domestic pets, millions of stray dogs and cats are euthanized every year. To support conservation efforts, consider donating to the World Wildlife Fund here. You can also check out the ASPCA website or Petfinder.com for more information on how to help domestic animals in need of a home.

Here are the best animal videos from 2012. "Like" your favorites, and tell us other great videos in the comments below!

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Source: http://www.huffingtonpost.com/2012/12/22/best-animal-videos-2012_n_2324165.html

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Relationships Initiate Self-Improvement ? Dr. Diva PhD Online ...

Relationships Initiate?Self-Improvement

Posted by Dr. Diva Verdun on December 21, 2012 ? Leave a Comment?

Looking at the way our relationships are structured we learn to use them as mirror reflections to find the things within ourselves that we need to focus our attention on.? As long as we are looking at the person that holds our affections with a critical eye, we are not focused on the reality that the reflection we see in the mirror is actually pointing at the issues we need to address within.

No matter how much we try to change someone else we cannot.? People only change when they find a reason to make improvements within and not before. By chastising and criticizing your beloved, you are actually driving a wedge into the relationship bond.? You are breaking down the bridge from which love freely flows.? Where you see they need to make self-improvement is also a marker that is pointing directly back to you, so that you can find the very same similarities within yourself.

Relationships are a slippery slope.? You can get so caught up in attempting to improve someone else?s behavior and character, that you are not even aware of your own.? A relationship can only level off to the height of your awareness of self.? Thus, if you are not aware of the internal struggles you are experiencing, you will continue to attract others into your experience that bring trials and challenges that are designed to point you in the direction of your own healing.

The miraculous thing about bonding relationships is the growth that both parties receive in the experience. When both people are working to improve themselves, the need to criticize and chastise each other falls away and becomes true deep loving support of each others individual and spiritual growth.

To often we want to control and force the other person into their healing to satisfy our own needs and fears.? The amazing thing about relationships is that the other person is limited in their growth and healing unless we are growing and healing as well.? Thus, no amount of force, pressure or control can move them one step forward in their own growth and healing.

If there is no growth and healing on an individual level, your relationship will become stagnant and dry-up resulting in either a break-up, because one person is growing and the other is not, or level off into a complacent and withered experience void of love and passion as the you both continue to simply co-exist in your pain.

Relationships Initiate Self-Improvement - Dr. Diva VerdunWhat you desire in a relationship is yours to have.? The person you attract to you is always right in the moment that they come into your experience.? They mirror exactly all you are at that particular moment, both the good and the bad.? Sadly, most people are not adept in many cases to be aware of this truth and don?t realize that the relationship is also mirroring your bad qualities as well, when you see them in your beloved.

Seeing yourself in the mirror of your relationship can be a beautiful experience when you see love, compassion, passion, trust, and all the other wonderful things that come with the union you are enjoying.? Sadly, you do not readily welcome seeing the bad.? However, when you begin to exercise self-mastery, you become aware that all things that happen for your bad, both big and small, in relationships and otherwise, are all designed for your good.? You become fully aware that your good manifest through you and you become disciplined to use every opportunity to work on your own issues, knowing that as you do everything else will level-off to your new state of awareness, including seeing growth and changes in your beloved and the relationship.

Relationships are not simply about love and passion and all the wonderful things that come with them.? They are key elements in your own growth in the equation of higher levels of awareness and spirituality. When you begin to exercise self-mastery to go deeper to carve out your own negative thinking and deal with your own pain, your behavior and character patterns change, which directly improve your relationship by either ending one that does not serve you, improving the one you have, as both people grow in Divine Love as Spirit makes the adjustments, or you begin to attract new people into your experience with fresh new mirrors.

Namaste!

Diva

Click here for a prayer treatment as you move into using your relationships for self-improvement

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Filed under Empowerment & Motivation, Exercising Independence, Love & Relationships, positive mental attitude, Spiritual ? Tagged with Acceptance, Achieving your dreams, divine power, divine presence, Dr Diva Phd, Empowerment, How to, infinite intelligence, Life, Life Coaching, lifestyle, living, living life, Love, love and relationships, love and relatioships, mental-health, Metaphysics, mirror reflections, mirrors, Motivation, Personal Development, positive spirituality, relationship mirrors, relationships, Self Help, Self-Esteem, self-improvement, self-mastery, Spiritual, spiritual mind treatment, spirituality, stop criticising your mate and look at yourself, Success, Success Coach

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New data challenge old views about evolution of early life

[ Back to EurekAlert! ] Public release date: 23-Dec-2012
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Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California - Riverside

UC Riverside-led research team rules out zinc as a factor in the delayed diversification of single-celled and multicellular organisms

RIVERSIDE, Calif. A research team led by biogeochemists at the University of California, Riverside has tested a popular hypothesis in paleo-ocean chemistry, and proved it false.

The fossil record indicates that eukaryotes single-celled and multicellular organisms with more complex cellular structures compared to prokaryotes, such as bacteria show limited morphological and functional diversity before 800-600 million years ago. Many researchers attribute the delayed diversification and proliferation of eukaryotes, which culminated in the appearance of complex animals about 600 million years ago, to very low levels of the trace metal zinc in seawater.

As it is for humans, zinc is essential for a wide range of basic cellular processes. Zinc-binding proteins, primarily located in the cell nucleus, are involved in the regulation of gene transcription.

Eukaryotes have increasingly incorporated zinc-binding structures during the last third of their evolutionary history and still employ both early- and late-evolving zinc-binding protein structures. Zinc is, therefore, of particular importance to eukaryotic organisms. And so it is not a stretch to blame the 1-2-billion-year delay in the diversification of eukaryotes on low bioavailability of this trace metal.

But after analyzing marine black shale samples from North America, Africa, Australia, Asia and Europe, ranging in age from 2.7 billion years to 580 million years old, the researchers found that the shales reflect high seawater zinc availability and that zinc concentrations during the Proterozoic (2.5 billion to 542 million years ago) were similar to modern concentrations. Zinc, the researchers posit, was never biolimiting.

Study results appear online Dec. 23 in Nature Geoscience.

"We argue that the concentration of zinc in ancient marine black shales is directly related to the concentrations of zinc in seawater and show that zinc is abundant in these rocks throughout Earth's history," said Clint Scott, the first author of the research paper and a former UC Riverside graduate student. "We found no evidence for zinc biolimitation in seawater."

Scott, now a research geologist with the U.S. Geological Survey, explained that the connection between zinc limitation and the evolution of eukaryotes was based largely on the hypothesis that Proterozoic oceans were broadly sulfidic. Under broadly sulfidic conditions, zinc should have been scarce because it would have rapidly precipitated in the oceans, he explained.

"However, a 2011 research paper in Nature also published by our group at UCR demonstrated that Proterozoic oceans were more likely broadly ferruginous that is, low in oxygen and iron-rich and that sulfidic conditions were more restricted than previously thought," said Scott, who performed the research in the lab of Timothy Lyons, a professor of biogeochemistry and the principal investigator of the research project.

The research team argues that ferruginous deep oceans, combined with large hydrothermal fluxes of zinc via volcanic activity on the seafloor, maintained high levels of dissolved zinc throughout the oceans and provided a relatively stable marine reservoir of the trace metal over the past 2.7 billion years.

"The key challenge in understanding the early evolution of life is recognizing the environmental conditions under which that life first appeared and diversified," Lyons said. "We have taken a very direct approach that specifically tracks the availability of essential micronutrients, and, to our surprise, zinc supplies in ancient seawater were much higher and less variable than previously imagined.

"We can imagine for the first time," he quipped, "that zinc supplements were not on the shopping lists of our early eukaryotic ancestors, and so we better find another reason to explain the mysterious delay in their rise in the ocean."

###

Scott, who graduated with a doctoral degree in geological sciences from UCR in 2009, and Lyons were joined in the study by Noah J. Planavsky, a former UCR graduate student in Lyons' lab; Chris L. Dupont at the J. Craig Venter Institute, La Jolla, Calif.; Brian Kendall and Ariel D. Anbar at Arizona State University; Benjamin C. Gill at Virginia Polytechnic Institute and State University and also a former member of the Lyons lab; Leslie J. Robbins and Kurt O. Konhauser at the University of Alberta, Canada; Kathryn F. Husband and Simon W. Poulton at the University of Leeds, United Kingdom; Gail L. Arnold at the Max Planck Institute for Marine Microbiology, Germany; Boswell A. Wing at McGill University, Canada; and Andrey Bekker at the University of Manitoba, Canada.

The idea for the study was a direct consequence of the 2011 Nature paper by Planavsky, Scott, Lyons and others that challenged the hypothesis of broadly sulfidic oceans.

The international collaboration received funding for the study from numerous sources. In the U.S., funding came from the National Science Foundation, the NASA Astrobiology Institute and the Agouron Institute.

The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus will open a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.



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[ Back to EurekAlert! ] Public release date: 23-Dec-2012
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Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California - Riverside

UC Riverside-led research team rules out zinc as a factor in the delayed diversification of single-celled and multicellular organisms

RIVERSIDE, Calif. A research team led by biogeochemists at the University of California, Riverside has tested a popular hypothesis in paleo-ocean chemistry, and proved it false.

The fossil record indicates that eukaryotes single-celled and multicellular organisms with more complex cellular structures compared to prokaryotes, such as bacteria show limited morphological and functional diversity before 800-600 million years ago. Many researchers attribute the delayed diversification and proliferation of eukaryotes, which culminated in the appearance of complex animals about 600 million years ago, to very low levels of the trace metal zinc in seawater.

As it is for humans, zinc is essential for a wide range of basic cellular processes. Zinc-binding proteins, primarily located in the cell nucleus, are involved in the regulation of gene transcription.

Eukaryotes have increasingly incorporated zinc-binding structures during the last third of their evolutionary history and still employ both early- and late-evolving zinc-binding protein structures. Zinc is, therefore, of particular importance to eukaryotic organisms. And so it is not a stretch to blame the 1-2-billion-year delay in the diversification of eukaryotes on low bioavailability of this trace metal.

But after analyzing marine black shale samples from North America, Africa, Australia, Asia and Europe, ranging in age from 2.7 billion years to 580 million years old, the researchers found that the shales reflect high seawater zinc availability and that zinc concentrations during the Proterozoic (2.5 billion to 542 million years ago) were similar to modern concentrations. Zinc, the researchers posit, was never biolimiting.

Study results appear online Dec. 23 in Nature Geoscience.

"We argue that the concentration of zinc in ancient marine black shales is directly related to the concentrations of zinc in seawater and show that zinc is abundant in these rocks throughout Earth's history," said Clint Scott, the first author of the research paper and a former UC Riverside graduate student. "We found no evidence for zinc biolimitation in seawater."

Scott, now a research geologist with the U.S. Geological Survey, explained that the connection between zinc limitation and the evolution of eukaryotes was based largely on the hypothesis that Proterozoic oceans were broadly sulfidic. Under broadly sulfidic conditions, zinc should have been scarce because it would have rapidly precipitated in the oceans, he explained.

"However, a 2011 research paper in Nature also published by our group at UCR demonstrated that Proterozoic oceans were more likely broadly ferruginous that is, low in oxygen and iron-rich and that sulfidic conditions were more restricted than previously thought," said Scott, who performed the research in the lab of Timothy Lyons, a professor of biogeochemistry and the principal investigator of the research project.

The research team argues that ferruginous deep oceans, combined with large hydrothermal fluxes of zinc via volcanic activity on the seafloor, maintained high levels of dissolved zinc throughout the oceans and provided a relatively stable marine reservoir of the trace metal over the past 2.7 billion years.

"The key challenge in understanding the early evolution of life is recognizing the environmental conditions under which that life first appeared and diversified," Lyons said. "We have taken a very direct approach that specifically tracks the availability of essential micronutrients, and, to our surprise, zinc supplies in ancient seawater were much higher and less variable than previously imagined.

"We can imagine for the first time," he quipped, "that zinc supplements were not on the shopping lists of our early eukaryotic ancestors, and so we better find another reason to explain the mysterious delay in their rise in the ocean."

###

Scott, who graduated with a doctoral degree in geological sciences from UCR in 2009, and Lyons were joined in the study by Noah J. Planavsky, a former UCR graduate student in Lyons' lab; Chris L. Dupont at the J. Craig Venter Institute, La Jolla, Calif.; Brian Kendall and Ariel D. Anbar at Arizona State University; Benjamin C. Gill at Virginia Polytechnic Institute and State University and also a former member of the Lyons lab; Leslie J. Robbins and Kurt O. Konhauser at the University of Alberta, Canada; Kathryn F. Husband and Simon W. Poulton at the University of Leeds, United Kingdom; Gail L. Arnold at the Max Planck Institute for Marine Microbiology, Germany; Boswell A. Wing at McGill University, Canada; and Andrey Bekker at the University of Manitoba, Canada.

The idea for the study was a direct consequence of the 2011 Nature paper by Planavsky, Scott, Lyons and others that challenged the hypothesis of broadly sulfidic oceans.

The international collaboration received funding for the study from numerous sources. In the U.S., funding came from the National Science Foundation, the NASA Astrobiology Institute and the Agouron Institute.

The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus will open a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.



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AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.


Source: http://www.eurekalert.org/pub_releases/2012-12/uoc--ndc122112.php

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