Precision motion tracking -- thousands of cells at once: Technique could open new windows into protozoan behavior, microbial diseases and fertility

ScienceDaily (Sep. 17, 2012) — Researchers have developed a new way to observe and track large numbers of rapidly moving objects under a microscope, capturing precise motion paths in three dimensions.

Over the course of the study -- reported online Sept. 17, 2012, in the Proceedings of the National Academy of Sciences -- researchers followed an unprecedented 24,000 rapidly moving cells over wide fields of view and through large sample volumes, recording each cell's path for as long as 20 seconds.

"We can very precisely track the motion of small things, more than a thousand of them at the same time, in parallel," says research lead and National Science Foundation CAREER awardee Aydogan Ozcan, an electrical engineering and bioengineering professor at UCLA. "We were able to achieve sub-micron accuracy over a large volume, allowing us to understand, statistically, how thousands of objects move in different ways."

The latest study is an extension of several years of NSF-supported work by Ozcan and his colleagues to develop lens-free, holographic microscopy techniques with applications for field-based detection of blood-borne diseases and other areas of tele-medicine.

For the recent work, Ozcan and his colleagues--Ting-Wei Su, also of UCLA, and Liang Xue, of both UCLA and Nanjing University of Science and Technology in China--used offset beams of red and blue light to create holographic information that, when processed using sophisticated software, accurately reveal the paths of objects moving under a microscope. The researchers tracked several cohorts of more than 1,500 human male gamete cells over a relatively wide field of view (more than 17 square millimeters) and large sample volume (up to 17 cubic millimeters) over several seconds.

The technique, along with a novel software algorithm that the team developed to process observational data, revealed previously unknown statistical pathways for the cells. The researchers found that human male gamete cells travel in a series of twists and turns along a constantly changing path that occasionally follows a tight helix--a spiral that, 90 percent of the time, is in a clockwise (right-handed) direction.

Because only four to five percent of the cells in a given sample traveled in a helical path at any given time, researchers would not have been able to observe the rare behavior without the new high-throughput microscopy technique.

"This latest study is an extension of truly novel and creative work," says Leon Esterowitz, the NSF biophotonics program officer who has supported Ozcan's efforts. "The holographic technique could accelerate drug discovery and prove valuable for monitoring pharmaceutical treatments of dangerous microbial diseases."

The PNAS paper reports observations of 24,000 cells over the duration of the experiments. Such a large number of observations provide a statistically significant dataset and a useful methodology for potentially studying a range of subjects, from the impact of pharmaceuticals and other substances on large numbers of cells--in real time--to fertility treatments and drug development.

The same approach may also enable scientists to study quick-moving, single-celled microorganisms. Many of the dangerous protozoa found in unsanitary drinking water and rural bodies of water have only been observed in small samples moving through an area that is roughly two dimensional. The new lens-free holographic imaging technique could potentially reveal unknown elements of protozoan behavior and allow real-time testing of novel drug treatments to combat some of the most deadly forms of those microbes.

Ozcan's research receives support from an NIH Director's New Innovator Award, Office of Naval Research Young Investigator Award and an Army Research Office Young Investigator Award from the Department of Defense.

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Journal Reference:

1. Ting-Wei Su, Liang Xue, and Aydogan Ozcan. High-throughput lensfree 3D tracking of human sperms reveals rare statistics of helical trajectories. PNAS, September 17, 2012 DOI: 10.1073/pnas.1212506109

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18 Sep, 2012

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Dry-run experiments verify key aspect of nuclear fusion concept: Scientific 'break-even' or better is near-term goal

ScienceDaily (Sep. 17, 2012) — Magnetically imploded tubes called liners, intended to help produce controlled nuclear fusion at scientific "break-even" energies or better within the next few years, have functioned successfully in preliminary tests, according to a Sandia research paper accepted for publication by Physical Review Letters (PRL).

To exceed scientific break-even is the most hotly sought-after goal of fusion research, in which the energy released by a fusion reaction is greater than the energy put into it -- an achievement that would have extraordinary energy and defense implications.

That the liners survived their electromagnetic drubbing is a key step in stimulating further Sandia testing of a concept called MagLIF (Magnetized Liner Inertial Fusion), which will use magnetic fields and laser pre-heating in the quest for energetic fusion.

In the dry-run experiments just completed, cylindrical beryllium liners remained reasonably intact as they were imploded by huge magnetic field of Sandia's Z machine, the world's most powerful pulsed-power accelerator. Had they overly distorted, they would have proved themselves incapable of shoveling together nuclear fuel -- deuterium and possibly tritium -- to the point of fusing them. Sandia researchers expect to add deuterium fuel in experiments scheduled for 2013.

"The experimental results -- the degree to which the imploding liner maintained its cylindrical integrity throughout its implosion -- were consistent with results from earlier Sandia computer simulations," said lead researcher Ryan McBride."These predicted MagLIF will exceed scientific break-even."

A simulation published in a 2010 Physics of Plasmas article by Sandia researcher Steve Slutz showed that a tube enclosing preheated deuterium and tritium, crushed by the large magnetic fields of the 25-million-ampere Z machine, would yield slightly more energy than is inserted into it.

A later simulation, published last January in PRL by Slutz and Sandia researcher Roger Vesey, showed that a more powerful accelerator generating 60 million amperes or more could reach "high-gain" fusion conditions, where the fusion energy released greatly exceeds (by more than 1,000 times) the energy supplied to the fuel.

These goals -- both the near-term goal of scientific break-even on today's Z machine and the long-term goal of high-gain fusion on a future, more powerful machine -- require the metallic liners to maintain sufficient cylindrical integrity while they implode.

The liner is intended to contain fusion fuel like a can holds peanut butter, and push it together in nanoseconds like two semicylindrical shovels compacting snow together.

An element of drama is present because the metallic liner doing the compressing is also being eaten away as it conducts the Z machine's enormous electrical current along its outer surface. This electrical current generates the corresponding magnetic field that crushes the liner, but under the stress of passing that current, the outer surface of the liner begins to vaporize and turn into plasma, in much the same way as a car fuse vaporizes when a short circuit sends too much current through it. As this happens, the surface begins to lose integrity and becomes unstable. This instability works its way inward, toward the liner's inner surface, throughout the course of the implosion.

"You might say: The race is on," said McBride. "The question is, can we start off with a thick enough tube such that we can complete the implosion and burn the fusion fuel before the instability eats its way completely through the liner wall?

"A thicker tube would be more robust in standing up to this instability, but the implosion would be less efficient because Z would have to accelerate more liner mass. On the flip side, a thinner tube could be accelerated to a much higher implosion velocity, but then the instability would rip the liner to shreds and render it useless," he continues. "Our experiments were designed to test a sweet spot predicted by the simulations where a sufficiently robust liner could implode with a sufficiently high velocity."

By following the dimensions proposed by the earlier simulations, the physical test proved successful and the liner walls maintained their integrity throughout the implosion. Radiographs taken at nanosecond intervals depicted the implosion of the initially solid beryllium liner through to stagnation -- the point at which an implosion stops because the liner material has reached the cylinder's central axis. The images show the outer surface of the imploding liner distorting until it resembles threads on a bolt. However, the more crucial inner surface remains reasonably intact all the way through to stagnation.

Said McBride's manager Dan Sinars, "When Magnetized Liner Inertial Fusion was first proposed, our biggest concern was whether the instabilities would disrupt the target before fusion reactions could occur. We had complex computer simulations that suggested things would be OK, but we were not confident in those predictions. Then McBride did his experiments, using liners with the same dimensions as our simulations, and the outcomes matched. We are now confident enough to take the next steps on the Z facility of integrating in the new magnetic field and laser preheat capabilities that will be required to test the full concept. Consequently, we intend to take those first integration steps in 2013."

Slated for December are the first tests of the final two components of the MagLIF concept: laser preheating to put more energy into the fuel before magnetic compression begins, and the testing of two secondary electrical coils placed at the top and bottom of the can. Their magnetic fields are expected to keep charged particles from escaping the hot fuel horizontally. This is crucial because if too many particles escape, the fuel could cool to the point where fusion reactions cease.

Sandia researchers intend to test the fully integrated MagLIF concept by the close of 2013.

"This work is one more step on a long path to possible energy applications," said Sandia senior manager Mark Herrmann.

The liner implosion experiments also served to verify that simulation tools like the popular LASNEX code are accurate within certain parameters, but may diverge when used beyond those limits -- information of importance to other labs that use the same codes. McBride will give an invited talk on his work this fall at the American Physical Society's annual Division of Plasma Physics meeting in Providence, RI. He is also preparing an invited paper for Physics of Plasmas to explain the PRL results in greater depth.

The work was funded by Sandia's Laboratory Directed Research and Development program and the National Nuclear Security Administration.

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18 Sep, 2012

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Sex matters: Men recognize cars and women recognize living things best, psychological analysis finds

ScienceDaily (Sep. 17, 2012) — Women are better than men at recognizing living things and men are better than women at recognizing vehicles.

That is the unanticipated result of an analysis Vanderbilt psychologists performed on data from a series of visual recognition tasks collected in the process of developing a new standard test for expertise in object recognition.

"These results aren't definitive, but they are consistent with the following story," said Gauthier. "Everyone is born with a general ability to recognize objects and the capability to get really good at it. Nearly everyone becomes expert at recognizing faces, because of their importance for social interactions. Most people also develop expertise for recognizing other types of objects due to their jobs, hobbies or interests. Our culture influences which categories we become interested in, which explains the differences between men and women."

The results were published online on Aug. 3 in the Vision Research journal in an article titled, "The Vanderbilt Expertise Test Reveals Domain-General and Domain-Specific Sex Effects in Object Recognition."

"Our motivation was to assess the role that expertise plays in object recognition with a new test that includes many different categories, so we weren't looking for this result," said Professor of Psychology Isabel Gauthier. She directs the lab where post-doctoral fellow Rankin McGugin conducted the study.

"This isn't the first time that sex differences have been found in perceptual tasks. For example, previous studies have shown that men have an advantage in mental rotation tasks. In fact, a recent study looking only at car recognition found that men were better than women but attributed this to the male advantage in mental rotation. Our finding that women are better than men at recognizing objects in other categories suggests that this explanation is incorrect."

Discovery of the sex effect in object recognition also casts doubt on several studies that claim an individual's ability to recognize faces is largely independent of his or her ability to recognize objects.

"Face recognition abilities are exciting to study because they have been found to have a clear genetic basis," said Gauthier, "and many studies conclude that abilities in face recognition are not predicted by abilities in object recognition. But this is usually based on comparing faces to only one object category for men and women."

It took the multi-category analysis to reveal that face recognition abilities are correlated to the ability to recognize different object categories for men and women. For example, men who are better at recognizing vehicles also tend to be better at recognizing faces, while women who are better at recognizing living things tend to be better at recognizing faces.

The researchers modeled their new test after the well-established Cambridge Face Memory Task, which effectively measures a person's ability to recognize faces. After familiarizing themselves with a number of images, participants are shown three images at a time -- one from the study group and two that they haven't seen before -- and then are asked to pick out the image that they had studied.

While one goal of the new study was to compare object and face recognition skills, another goal was to develop a better way to measure who has exceptional skills in one domain: how to find the experts in the recognition of cars or birds or even mushrooms. To do this, the Vanderbilt researchers reasoned that performance on any category of interest needed to be compared to performance on many other categories, to ensure that the self-proclaimed bird expert is not only better with birds than most people, but also better with birds than with most other categories. So they designed the new test with eight categories of visually similar objects: leaves, owls, butterflies, wading birds, mushrooms, cars, planes and motorcycles.

To evaluate the new test, they administered it to 227 subjects -- 75 male and 82 female -- with a mean age of 23. When the results of the entire group were analyzed, the researchers found that increasing the number of categories revealed a large sex difference: Women proved significantly better at recognizing living things while men were better at recognizing vehicles. In addition, the researchers administered a face recognition test to about half of the participants, which allowed them to determine the correlation between vehicle recognition and face recognition in men and the correlation between recognition of living things and faces in women.

Vanderbilt post-doctoral fellow Jennifer Richler as well as Grit Herzmann, a post-doctoral fellow at the University of Colorado, Boulder and Research Assistant Magen Speegle also contributed to the study.

The research was supported by the National Eye Institute grants EYO13441-06A2 and P30-EY008126 and by the National Science Foundation's Temporal Dynamics of Learning Center grant SBE-0542013.

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Journal Reference:

1. Rankin W. McGugin, Jennifer J. Richler, Grit Herzmann, Magen Speegle, Isabel Gauthier. The Vanderbilt Expertise Test reveals domain-general and domain-specific sex effects in object recognition. Vision Research, 2012; 69: 10 DOI: 10.1016/j.visres.2012.07.014

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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.

18 Sep, 2012

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Mobile phones and wireless networks: No evidence of health risk found, Norwegian experts find

ScienceDaily (Sep. 17, 2012) — There is no scientific evidence that low-level electromagnetic field exposure from mobile phones and other transmitting devices causes adverse health effects, according to a report presented by a Norwegian Expert Committee. In addition, the Committee provides advice to authorities about risk management and regulatory practice.

The Committee has assessed the health hazards from low-level electromagnetic fields generated by radio transmitters. These electromagnetic fields are found around mobile phones, wireless phones and networks, mobile phone base stations, broadcasting transmitters and other communications equipment. The Committee has evaluated the power of the fields, whether they pose a health risk, the current regulatory practice, and whether the threshold limit values for exposure are observed.

The report is entitled "Svake høyfrekvente elektromagnetiske felt -- en vurdering av helserisiko og forvaltningspraksis. FHI-rapport 2012:3" (In English: Low-level radiofrequency electromagnetic fields -- an assessment of health risks and evaluation of regulatory practice. NIPH report 2012:3). Published on September 13th, the report contains a Norwegian and English summary.

Studied electromagnetic fields below threshold limit values

The low-level electromagnetic fields generated when antennas in mobile phones and other wireless devices transmit radio signals are referred to as radiofrequency (RF) fields.

The health authorities have determined that the threshold limit values for electromagnetic fields around transmitters in mobile phones and other equipment should be the same as those recommended by the International Commission on Non-ionising Radiation Protection (ICNIRP). The threshold limit values are based on fields above a certain power that can cause harmful heating of tissue. The ICNIRP has not observed other adverse health effects under this level.

The threshold limit values for these fields are 50 times below the level that causes heating of human tissue or stimulation of nerve cells. Due to increasing public concerns, the government requested the appointment of an Expert Committee to assess whether such low-level electromagnetic fields could cause health effects.

The Norwegian Institute of Public Health was commissioned to appoint the Expert Committee by the Ministry of Health and Care Services and the Ministry of Transport and Communication. The Committee was chaired by Professor Jan Alexander, Assistant Director-General at the Institute.

Research indicates no health risk

The Committee has assessed a number of possible health effects from low-level electromagnetic fields and has evaluated the research in each area.

The group found no evidence that the low-level fields around mobile phones and other transmitters increase the risk of cancer, impair male fertility, cause other reproductive damage or lead to other diseases and adverse health effects, such as changes to the endocrine and immune systems.

No cancer risk found

Most studies concerning cancer have focused on the risk of cancer in the head and neck. The Committee found no scientific evidence for an association between mobile phone use and fast-growing brain tumours. So far, the effect on slow-growing tumours has been studied in people who have used mobile phones for up to 20 years. These studies show no association.

Only limited data exist for the other types of cancer in the head and neck area, as well as for leukaemia and lymphoma, but so far there is no evidence of an increased risk from mobile phone use. Cancer registries have not observed an increase in these tumours in the population since mobile phones were introduced.

Electromagnetic hypersensitivity

The Committee did not find that mobile phones and other equipment can cause health problems such as electromagnetic hypersensitivity.

Does this mean that electromagnetic hypersensitivity is an imaginary problem? "We have no grounds to say that the symptoms are imaginary. But a large number of studies suggest that these symptoms must have other causes than the physical effects of low-level electromagnetic fields around mobile phones, wireless transmitters and other wireless equipment. Research provides no evidence to support that interventions help, such as reducing the use of mobile phones or wireless networks. Our opinion is that patients with these health problems must be taken seriously by the health service and should be treated as other patients. There is a need for greater expertise in the health service for this group of patients," says Alexander.

Many people have found that holding a mobile phone to the head causes the area around the ear to become hot -- is this due to electromagnetic radiation? "The skin warms up slightly due to heat from the battery and not from the radio transmitter in the phone. The electromagnetic field will have very little or no heating effect. The body will remove the heat through normal blood flow, in the same way as the body otherwise regulates temperature."

Some mobile phone models transmitting at maximum power provide exposure that comes close to the threshold limit values. Even so, any heating due to electromagnetic fields would be negligible.

Advice: Show general caution

Since there are no uncertainties in the health risk assessment of low-level electromagnetic fields that warrant introduction of the precautionary principle, the Committee believes that general caution is sufficient. This means that exposure should not be higher than needed to achieve the intended purpose.

When comparing the power of the fields around different types of equipment, talking on a mobile phone tops the list, whilst wireless internet networks are at the bottom. Base stations and broadcasting transmitters also come low down in the list. An example of exercising general caution would be for the authorities to inform that hands-free kits will significantly reduce exposure from mobile phones.

Furthermore, the field strength around a mobile phone is lower when there is good coverage.

Little benefit from more research

The Committee has evaluated the assessments previously published by international expert groups, as well as recent individual studies. The material is very extensive. A number of studies were performed on cells and tissues in the laboratory, as well as in animals and humans. In addition, population studies and cancer registry studies were conducted in several countries.

Little uncertainty

There is always an element of uncertainty in all risk assessments. In this case, the Committee considers the uncertainty to be small. Some uncertainty is associated with high exposure over time, such as extensive use of mobile phones over several decades. Until now, this has been impossible to study. Cancer registries should follow the development of cancer incidence in the future and research should not cease. Studies of animals that have been exposed throughout life provide no evidence that low level RF fields cause cancer. It is unlikely that long-term use of mobile phones will cause health risks that are unknown today.

Regarding equipment that provides the lowest exposure, such as base stations, wireless networks, broadcasting transmitters and proximity to other mobile phones, the experts believe that the risk assessment has negligible uncertainty. In other words, it is reasonably certain that such equipment is not associated with health risks.

The report is approximately 200 pages long and includes Norwegian and English summaries. It can be downloaded in PDF format at http://www.fhi.no.

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17 Sep, 2012

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World’s most powerful digital camera opens eye, records first images in hunt for dark energy

ScienceDaily (Sep. 17, 2012) — Eight billion years ago, rays of light from distant galaxies began their long journey to Earth. That ancient starlight has now found its way to a mountaintop in Chile, where the newly-constructed Dark Energy Camera, the most powerful sky-mapping machine ever created, has captured and recorded it for the first time.

That light may hold within it the answer to one of the biggest mysteries in physics -- why the expansion of the universe is speeding up.

Scientists in the international Dark Energy Survey collaboration announced this week that the Dark Energy Camera, the product of eight years of planning and construction by scientists, engineers, and technicians on three continents, has achieved first light. The first pictures of the southern sky were taken by the 570-megapixel camera on Sept. 12.

"The achievement of first light through the Dark Energy Camera begins a significant new era in our exploration of the cosmic frontier," said James Siegrist, associate director of science for high energy physics with the U.S. Department of Energy. "The results of this survey will bring us closer to understanding the mystery of dark energy, and what it means for the universe."

The Dark Energy Camera was constructed at the U.S. Department of Energy's (DOE) Fermi National Accelerator Laboratory in Batavia, Illinois, and mounted on the Victor M. Blanco telescope at the National Science Foundation's Cerro Tololo Inter-American Observatory (CTIO) in Chile, which is the southern branch of the U.S. National Optical Astronomy Observatory (NOAO). With this device, roughly the size of a phone booth, astronomers and physicists will probe the mystery of dark energy, the force they believe is causing the universe to expand faster and faster.

"The Dark Energy Survey will help us understand why the expansion of the universe is accelerating, rather than slowing due to gravity," said Brenna Flaugher, project manager and scientist at Fermilab. "It is extremely satisfying to see the efforts of all the people involved in this project finally come together."

The Dark Energy Camera is the most powerful survey instrument of its kind, able to see light from over 100,000 galaxies up to 8 billion light years away in each snapshot. The camera's array of 62 charged-coupled devices has an unprecedented sensitivity to very red light, and along with the Blanco telescope's large light-gathering mirror (which spans 13 feet across), will allow scientists from around the world to pursue investigations ranging from studies of asteroids in our own Solar System to the understanding of the origins and the fate of the universe.

"We're very excited to bring the Dark Energy Camera online and make it available for the astronomical community through NOAO's open access telescope allocation," said Chris Smith, director of the Cerro-Tololo Inter-American Observatory. "With it, we provide astronomers from all over the world a powerful new tool to explore the outstanding questions of our time, perhaps the most pressing of which is the nature of dark energy."

Scientists in the Dark Energy Survey collaboration will use the new camera to carry out the largest galaxy survey ever undertaken, and will use that data to carry out four probes of dark energy, studying galaxy clusters, supernovae, the large-scale clumping of galaxies and weak gravitational lensing. This will be the first time all four of these methods will be possible in a single experiment.

The Dark Energy Survey is expected to begin in December, after the camera is fully tested, and will take advantage of the excellent atmospheric conditions in the Chilean Andes to deliver pictures with the sharpest resolution seen in such a wide-field astronomy survey. In just its first few nights of testing, the camera has already delivered images with excellent and nearly uniform spatial resolution.

Over five years, the survey will create detailed color images of one-eighth of the sky, or 5,000 square degrees, to discover and measure 300 million galaxies, 100,000 galaxy clusters and 4,000 supernovae.

The Dark Energy Survey is supported by funding from the U.S. Department of Energy; the National Science Foundation; funding agencies in the United Kingdom, Spain, Brazil, Germany and Switzerland; and the participating DES institutions.

More information about the Dark Energy Survey, including the list of participating institutions, is available at the project website: www.darkenergysurvey.org.

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17 Sep, 2012

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Skilled hunters 300,000 years ago

[unable to retrieve full-text content]Finds from early stone age site in north-central Germany show that human ingenuity is nothing new -- and was probably shared by now-extinct species of humans. Archeologists have found eight extremely well-preserved spears -- an astonishing 300,000 years old, making them the oldest known weapons anywhere. The spears and other artifacts as well as animal remains found at the site demonstrate that their users were highly skilled craftsmen and hunters, well adapted to their environment -- with a capacity for abstract thought and complex planning comparable to our own.

17 Sep, 2012

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Most coral reefs are at risk unless climate change is drastically limited, study shows

ScienceDaily (Sep. 16, 2012) — Coral reefs face severe challenges even if global warming is restricted to the 2 degrees Celsius commonly perceived as safe for many natural and human-made systems. Warmer sea surface temperatures are likely to trigger more frequent and more intense mass coral bleaching events. Only under a scenario with strong action on mitigating greenhouse-gas emissions and the assumption that corals can adapt at extremely rapid rates, could two thirds of them be safe, shows a study now published in Nature Climate Change. Otherwise all coral reefs are expected to be subject to severe degradation.

Coral reefs house almost a quarter of the species in the oceans and provide critical services -- including coastal protection, tourism and fishing -- to millions of people worldwide. Global warming and ocean acidification, both driven by human-caused CO₂ emissions, pose a major threat to these ecosystems.

"Our findings show that under current assumptions regarding thermal sensitivity, coral reefs might no longer be prominent coastal ecosystems if global mean temperatures actually exceed 2 degrees Celsius above the pre-industrial level," says lead author Katja Frieler from the Potsdam Institute for Climate Impact Research. "Without a yet uncertain process of adaptation or acclimation, however, already about 70% of corals are projected to suffer from long-term degradation by 2030 even under an ambitious mitigation scenario." Thus, the threshold to protect at least half of the coral reefs worldwide is estimated to be below 1.5 degrees Celsius mean temperature increase.

A more comprehensive and robust representation than in previous studies

This study is the first comprehensive global survey of coral bleaching to express results in terms of global mean temperature change. It has been conducted by scientists from Potsdam, the University of British Columbia in Canada and the Universities of Melbourne and Queensland in Australia. To project the cumulative heat stress at 2160 reef locations worldwide, they used an extensive set of 19 global climate models. By applying different emission scenarios covering the 21st century and multiple climate model simulations, a total of more than 32,000 simulation years was diagnosed. This allows for a more robust representation of uncertainty than any previous study.

Corals derive most of their energy, as well as most of their famous color, from a close symbiotic relationship with a special type of microalgae. The vital symbiosis between coral and algae can break down when stressed by warm water temperatures, making the coral "bleach" or turn pale. Though corals can survive this, if the heat stress persists long enough the corals can die in great numbers. "This happened in 1998, when an estimated 16% of corals were lost in a single, prolonged period of warmth worldwide," says Frieler.

Adaptation is uncertain and ocean acidification means even more stress

To account for a possible acclimation or adaptation of corals to thermal stress, like shifts to symbiont algae with a higher thermal tolerance, rather optimistic assumptions have been included in the study. "However, corals themselves have all the wrong characteristics to be able to rapidly evolve new thermal tolerances," says co-author Ove Hoegh-Guldberg, a marine biologist at the University of Queensland in Australia. "They have long lifecycles of 5-100 years and they show low levels of diversity due to the fact that corals can reproduce by cloning themselves. They are not like fruit flies which can evolve much faster."

Previous analyses estimated the effect of thermal adaptation on bleaching thresholds, but not the possible opposing effect of ocean acidification. Seawater gets more acidic when taking up CO₂ from the atmosphere. This is likely to act to the detriment of the calcification processes crucial for the corals' growth and might also reduce their thermal resilience. The new study investigates the potential implications of this ocean acidification effect, finding that, as Hoegh-Guldberg says: "The current assumptions on thermal sensitivity might underestimate, not overestimate, the future impact of climate change on corals."

This comprehensive analysis highlights how close we are to a world without coral reefs as we know them. "The window of opportunity to preserve the majority of coral reefs, part of the world's natural heritage, is small," summarizes Malte Meinshausen, co-author at the Potsdam Institute for Climate Impact Research and the University of Melbourne. "We close this window, if we follow another decade of ballooning global greenhouse-gas emissions."

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Journal Reference:

1. K. Frieler, M. Meinshausen, A. Golly, M. Mengel, K. Lebek, S. D. Donner, O. Hoegh-Guldberg. Limiting global warming to 2 °C is unlikely to save most coral reefs. Nature Climate Change, 2012; DOI: 10.1038/NCLIMATE1674

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17 Sep, 2012

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Anak Alergi Terhadap Makanan

Anak Alergi Terhadap Makanan Joshua, anak laki-laki berusia 9 tahun ini memiliki alergi yang tak biasa. Para dokter menyebut, bahwa Joshua menderita penyakit yang disebut esofagitis eosinofilik, alergi terhadap hampir semua makanan.

Tak terkecuali, pizza, hot dog, dan apapun jenis makanan bisa membuatnya mengalami alergi. Joshua mungkin tidak memakannya, ia bahkan tak diizinkan untuk mencicipi sedikitpun atau bahkan menciumnya. Reaksi alergi bisa timbul jika aromanya tercium.

Karena sakit yang dideritanya, Joshua hanya mendapatkan makanan, sebagian besar melalui nutrisi lewat makanan formula yang diresepkan oleh dokternya. Ia juga harus menikmati makanan hanya melalui selang makanan di perutnya.

Seperti dikutip laman Shine, setiap hari, Joshua hanya belajar di rumah ditemani ibunya. Karena penyakitnya, ia  juga harus menjalani segala aktivitas dengan ekstra hati-hati.

Cara dan Brant, orangtua Joshua, menyatakan, setiap hari adalah hal yang menakutkan baginya karena harus selalu memantau makanan putranya.

Apa yang akan terjadi jika Joshua mengkonsumsi salah satu makanan yang bisa membuatnya alergi?  Ia bisa menderita sakit parah, bahkan, bisa juga membuatnya mati mendadak.

"Tidak ada satu menit yang berlalu tanpa kekhawatiran, setiap hari aku selalu takut," kata Cara.

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Promo Member Alfamart Minimarket Lokal Terbaik Indonesia

Bagi anda yang suka berbelanja tentunya tidak asing lagi dengan minimarket yang satu ini. Sebagai Minimarket Pertama yang memiliki member terbanyak di Indonesia Alfamart memberikan banyak inovasi untuk memanjakan membernya. Salah satunya adalah dengan konsisten 2 minggu sekali  memberikan Promo khusus untuk member-membernya baik untuk berbelanja di Alfamart atau pun di merchant-merchant yang banyak bekerja sama dengan Alfamart untuk memberikan potongan harga atau harga spesial.

Promo Member Alfamart Minimarket Lokal Terbaik Indonesia merupakan promosi Yang dilakukan Oleh Minimarket Lokal Terbesar dan Minimarket Pertama Terbaik Indonesia guna untuk menarik Simpati dan Perhatian lebih dari masyarakat untuk menjadi Member Alfamart dan khususnya pecinta Informasi internet dengan menyelenggarakan Promo Indonesia Kontes SEO Alfamart 2012.

Promo Member Alfamart Minimarket Lokal Terbaik Indonesia. Promo Indonesia ini diberikan oleh Alfamart sebagai Minimarket pertama yang mempunyai member terbanyak di Indonesia. Ketika mendengar kata "promo" pasti semua orang tertarik, karena pada setiap kegiatan promo pasti akan ada diskon, hadiah atau sesuatu yang menguntungkan lainnya. Dan kabar gembiranya, Alfamart sebagai minimarket besar Indonesia sedang mengadakan penawaran yang menarik, yaitu Promo Member Alfamart Minimarket Lokal Terbaik Indonesia. Promo Indonesia ini diberikan Alfamart untuk para calon member dan juga member Alfamart.

Minimarket Alfamart yang berdiri sejak tahun 1994 oleh PT. Sumber Alfaria Trijaya Tbk ini yang sekarang sudah memiliki banyak member dan merupakan member terbesar di Minimarket Indonesia. Pertumbuhan  Alfamart di Indonesia sangatlah pesat bak "jamur di musim hujan", terbukti dengan berdirinya cabang-cabang Alfamart yang tidak hanya di kota-kota besar tapi sampai ke pelosok-pelosok kecamatan di seluruh negeri Indonesia.

Alfamart Minimarket Pertama yang memiliki member terbanyak di Indonesia Alfamart Memberikan Motivasi dan Inspirasi serta Inovasi untuk memanjakan membernya. Salah satunya adalah dengan konsisten 2 minggu sekali  memberikan Promo Indonesia khusus untuk Member Alfamart baik untuk berbelanja di Alfamart Minimarket atau pun di merchant-merchant yang banyak bekerja sama dengan Alfamart Minimarket untuk memberikan potongan harga atau harga spesial.

Member Alfamart Adalah sebutan untuk para pelanggan setia Alfamart.Para member Alfamart akan mendapatkan berbagai macam keuntungan dan kejutan special dari Alfamart seperti: HematKu, Kalender Belanja, Specialku dan Hadiahku,serta program ekslusif lainnya. Member Alfamart adalah pelanggan yang memiliki dan bergabung dalam keanggotaan Kartu AKU, A Card Flazz atau Kartu AKU BNI Promo Member Alfamart Minimarket Lokal Terbaik Indonesia

KARTU AKU Promo Member Alfamart Minimarket Lokal Terbaik Indonesia

    Kartu Aku

Adalah kartu member yang pertama kali diluncurkan Alfamart pada tahun 2005. Dengan Kartu AKU, Member akan dapat memperoleh manfaat dan berbagai macam keuntungan serta Promo Indonesia menarik yang tidak dapat diikuti oleh pelanggan lain yang bukan merupakan member Kartu AKU. Kartu AKU berlaku Nasional di Alfamart seluruhIndonesia.

A CARD FINAL Promo Member Alfamart Minimarket Lokal Terbaik Indonesia
    A Card Flazz

Adalah Kartu Member Alfamart yang di luncurkan pada 15 Mei 2010 bekerja sama dengan Flazz BCA, yang selain berfungsi sebagai kartu member juga dapat digunakan sebagai alat pembayaran/transaksi karena A Card Flazz merupakan Kartu Prepaid (kartu non rekening yang dapat menyimpan uang untuk keperluan berbagai transaksi).

A Card Flazz dapat digunakan sebagai alat pembayaran tidak hanya diseluruh outlet Alfamart, Alfamidi ataupun Alfaexpress tetapi juga diseluruh merchant Flazz antara lain restoran, salon, toko buku, parkir, bioskop dan masih banyak lagi. Untuk sementara ini, A Card Flazz berlaku di Jabodetabek,Surabaya

KARTU AKU BNI Promo Member Alfamart Minimarket Lokal Terbaik Indonesia
    Kartu Aku BNI

Merupakan salah satu Kartu Member Alfamart yang di luncurkan pada 1 Januari 2010, merupakan kerjasama antara Alfamart dengan Bank BNI. Kartu AKU BNI merupakan kartu multifungsional, yang selain berfungsi sebagai kartu member, juga berfungsi sebagai alat pembayaran. Pengguna Kartu AKU BNI juga akan mendapatkan berbagai keuntungan dan kejutan spesial dari Alfamart serta tentunya dapat mengikuti program-program eksklusif khusus member di Alfamart. Untuk saat ini, Kartu AKU BNI berlaku di Alfamart Jabodetabek.
8 Keuntungan Member Alfamart

   1. Hematku dan Kalender Belanja
   2. Spesialku dan Hadiahku
   3. Special Big Program for "Member Alfamart"
   4. Redemption For "Member Alfamart"
   5. Member Alfamart" Thematic Promo
   6. Special Treatment for "Member Alfamart" Birthday
   7. Special Event/Activities For "Member Alfamart"
   8. Merchant For "Member Alfamart"

 

Demikianlah penjelasan singkat tentang  Promo Member Alfamart Minimarket Lokal Terbaik Indonesia Semoga dapat bermanfaat dan memberikan pengetahuan Lebih kepada masyarakat agar dapat bergabung menjadi Member Alfamart dan pastikan anda mendapakan keuntungan dan manfaat lebih dari Alfamart Minimarket Lokal Terbaik Indonesia

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Hidup Mesra Tak Kenal Usia

Hidup Mesra Tak Kenal Usia Lionel, 99, dan Ellen Buxton, 100, seolah tak terpisahkan. Menikah 76 tahun silam, pasangan asal Inggris itu membuktikan janji setianya.

Sejak memutuskan berumah tangga pada 1936, pasangan itu hanya sekali menghabiskan malam terpisah satu sama lain.

Raga yang melemah tak menghalangsi letupan kemesraan keduanya yang menakjubkan. "Kami selalu bahagia, kami adalah teman baik juga suami dan istri yang baik," kata Ellen, seperti dikutip mirror.co.uk.

Selama puluhan tahun itu pula mereka memiliki kebiasaan menghabiskan malam indah bersama. Tak melulu makan malam romantis, tapi juga sekadar bersenang-senang bermain bingo.

Mereka kebetulan juga memiliki ketertarikan sama di bidang olahraga seperti memanag, dan sepakbola.

Ellen dan Lionel pertama kali bertemu pada 1930, saat bekerja di pabrik kabel di Woolwich. Ellen yang menjadi teknisi di pabrik itu kerap meminta bantuan Lionel yang menjadi insinyur magang.

"Saya selalu menantikan dia meminta bantuan, jadi saya punya kesempatan untuk berbicara dengannya. Dia begitu baik. Dia cantik," kata Lionel, yang enam bulan lebih muda dari Ellen.

Berbagai liku kehidupan selama puluhan tahun rupanya tak mengikis kemesraan mereka. Termasuk saat Ellen bergulat dengan penyakit kanker dengan kemoterapi yang menyakitkan.

"Kami lebih cinta sekarang dari sebelumnya. Kami terus saling pergi. Kami bukti bahwa cinta sejati tidak pernah memudar," kata pasangan yang telah memiliki empat cucu itu.

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