Category Archives: Science

Scientific Inquiry Process Finds More Evidence Supporting Einstein’s Theory

As scientists have been able to see farther and deeper into the universe, the laws that govern its expansion have been revealed to be under the influence of an unexplained force.

In a paper on the arXiv, Astrophysical Tests of Modified Gravity: Constraints from Distance Indicators in the Nearby Universe, are a vindication of Einstein’s theory of gravity. Having survived several decades of tests in the solar system, it has passed this new test in galaxies beyond our own as well.

In 1998, astrophysicists made an observation that turned gravity on its ear: the universe’s rate of expansion is speeding up. If gravity acts the same everywhere, stars and galaxies propelled outward by the Big Bang should continuously slow down, like objects thrown from an explosion do here on Earth.

This observation used distant supernovae to show that the expansion of the universe was speeding up rather than slowing down. This indicated that something was missing from physicists’ understanding of how the universe responds to gravity, which is described by Einstein’s theory of general relativity. Two branches of theories have sprung up, each trying to fill its gaps in a different way.

One branch — dark energy — suggests that the vacuum of space has an energy associated with it and that energy causes the observed acceleration. The other falls under the umbrella of “scalar-tensor” gravity theories, which effectively posits a fifth force (beyond gravity, electromagnetism and the strong and weak nuclear forces) that alters gravity on cosmologically large scales.

“These two possibilities are both radical in their own way,” University of Pennsylvania astrophysicist Bhuvnesh Jain said. “One is saying that general relativity is correct, but we have this strange new form of energy. The other is saying we don’t have a new form of energy, but gravity is not described by general relativity everywhere.”

Jain’s research is focused on the latter possibility; he is attempting to characterize the properties of this fifth force that disrupts the predictions general relativity makes outside our own galaxy, on cosmic length scales. Jain’s recent breakthrough came about when he and his colleagues realized they could use the troves of data on a special property of a common type of star as an exquisite test of gravity.

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Modeling Weight Loss Over the Long Term

Researchers at the National Institutes of Health have created a mathematical model of what happens when people of varying weights, diets and exercise habits try to change their weight. The findings challenge the commonly held belief that eating 3,500 fewer calories, or burning them off exercising, will result in a pound of weight loss.

Instead, the researchers’ computer simulations indicate that this assumption overestimates weight loss because it fails to account for how metabolism changes. The computer simulations show how these metabolic changes can significantly differ among people.

However, the computer simulation of metabolism is meant as a research tool and not as a weight-loss guide for the public. The computer program can run simulations for changes in calories or exercise that would never be recommended for healthy weight loss. The researchers hope to use the knowledge gained from developing the model and from clinical trials in people to refine the tool for everyone.

“This research helps us understand why one person may lose weight faster or slower than another, even when they eat the same diet and do the same exercise,” said Kevin Hall, Ph.D., an obesity researcher and physicist at the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases. “Our computer simulations can then be used to help design personalized weight management programs to address individual needs and goals.”

The online simulation tool based on the model enables researchers to accurately predict how body weight will change and how long it will likely take to reach weight goals based on a starting weight and estimated physical activity. The tool simulates how factors such as diet and exercise can alter metabolism over time and thereby lead to changes of weight and body fat.

The team found that people’s bodies adapt slowly to changes in dietary intake. They also found heavier people can expect greater weight change with the same change in diet, though reaching a stable body weight will take them longer than people with less fat.

The model also points to a potential simplified method to approximate weight loss in an average overweight person. An adult who has a body mass index (a measure of a person’s weight in relation to his or her height) between 25 and 29.9 is considered overweight. One example: For every pound you want to lose, permanently cut 10 calories from your current intake per day. At that rate, it will take about one year to achieve half of the total weight loss, and almost all of the weight loss will have occurred by three years. This calculation shows how long it takes to achieve a weight-loss goal for a single permanent change of diet or exercise.

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Video of Young Richard Feynman Talking About Scientific Thinking

The enjoyable video above shows a young Richard Feynman discussing how scientific thinking can advance our understanding of the world.

Using Nanocomposites to Improve Dental Filling Performance

After a dentist drills out a decayed tooth, the cavity still contains residual bacteria. Professor Huakun (Hockin) Xu says it is not possible for a dentist to remove all the damaged tissue, so it’s important to neutralize the harmful effects of the bacteria, which is just what the new nanocomposites are able to do.

Rather than just limiting decay with conventional fillings, the new composite he has developed is a revolutionary dental weapon to control harmful bacteria, which co-exist in the natural colony of microorganisms in the mouth.

“Tooth decay means that the mineral content in the tooth has been dissolved by the organic acids secreted by bacteria residing in biofilms or plaques on the tooth surface. These organisms convert carbohydrates to acids that decrease the minerals in the tooth structure,” says Xu, director of the Division of Biomaterials and Tissue Engineering in the School’s Department of Endodontics, Prosthodontics and Operative Dentistry.

The researchers also have built antibacterial agents into primer used first by dentists to prepare a drilled-out cavity and into adhesives that dentists spread into the cavity to make a filling stick tight to the tissue of the tooth. “The reason we want to get the antibacterial agents also into primers and adhesives is that these are the first things that cover the internal surfaces of the tooth cavity and flow into tiny dental tubules inside the tooth,” says Xu.

The main reason for failures in tooth restorations, says Xu, is secondary caries or decay at the restoration margins. Applying the new primer and adhesive will kill the residual bacteria, he says.

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New Blog with Simple Demonstrations and Scientific Explanations

Try this at home is a new blog by Dr Mark Lorch, a chemistry lecturer at the University of Hull, with instructions for the citizen scientist. This example shows how to move a can with a ballon without touching the can.

The posts include instructions on how to do these simple demonstrations and a nice explanation on the scientific reason for what is going on:

Rubbing the balloon on your hair charges it up with static electricity which makes the balloon negatively charged. When you put the balloon near the can it pushes electrons (which are also negatively charged) to the other side of the can. This makes the side which is nearest the balloon positively charged. Positive charges are attracted to negative charges so the can moves towards the balloon.

It is quite a nice site (especially if you have kids interested in science or are a kid interested in science – no matter how old you are), add it to your RSS reader. Here are some more science blogs you may enjoy.

Fossil or Mystery Monster Found In Kentucky Seems to Defy All Known Groups of Organisms

Around 450 million years ago, shallow seas covered the Cincinnati region and harbored one very large and now very mysterious organism. Despite its size, no one has ever found a fossil of this “monster” until its discovery by an amateur paleontologist last year.

UC Paleontologist David Meyer, left and Carlton Brett, right, flank Ron Fine, who discovered the large fossil spread out on the table.

The fossilized specimen, a roughly elliptical shape with multiple lobes, totaling almost seven feet in length, will be unveiled at the North-Central Section 46th Annual Meeting of the Geological Society of America, April 24, in Dayton, Ohio.

Fine is a member of the Dry Dredgers, an association of amateur paleontologists based at the University of Cincinnati. The club, celebrating its 70th anniversary this month, has a long history of collaborating with academic paleontologists.

“I knew right away that I had found an unusual fossil,” Fine said. “Imagine a saguaro cactus with flattened branches and horizontal stripes in place of the usual vertical stripes. That’s the best description I can give.”

The layer of rock in which he found the specimen near Covington, Kentucky, is known to produce a lot of nodules or concretions in a soft, clay-rich rock known as shale. “While those nodules can take on some fascinating, sculpted forms, I could tell instantly that this was not one of them,” Fine said. “There was an ‘organic’ form to these shapes. They were streamlined.”

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Harvard Steps Up Defense Against Abusive Journal Publishers

For a decade journals have been trying to continue a business model that was defensible in a new world where it is not. They have becoming increasing abusive with even more outrageous fees than they were already charging. As I said years ago it has become obvious they are enemies of science and should be treated as such. The time to find mutual beneficial solution past years ago.

Harvard University says it can’t afford journal publishers’ prices

Exasperated by rising subscription costs charged by academic publishers, Harvard University has encouraged its faculty members to make their research freely available through open access journals and to resign from publications that keep articles behind paywalls.

A memo from Harvard Library to the university’s 2,100 teaching and research staff called for action after warning it could no longer afford the price hikes imposed by many large journal publishers, which bill the library around $3.5m a year.
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he memo from Harvard’s faculty advisory council said major publishers had created an “untenable situation” at the university by making scholarly interaction “fiscally unsustainable” and “academically restrictive”, while drawing profits of 35% or more. Prices for online access to articles from two major publishers have increased 145% over the past six years, with some journals costing as much as $40,000, the memo said.

More than 10,000 academics have already joined a boycott of Elsevier, the huge Dutch publisher, in protest at its journal pricing and access policies. Many university libraries pay more than half of their journal budgets to the publishers Elsevier, Springer and Wiley.
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Research Libraries UK negotiated new contracts with Elsevier and Wiley last year after the group threatened to cancel large subscriptions to the publishers. The new deal, organised on behalf of 30 member libraries, is expected to save UK institutions more than Â£20m.

These journals have continuously engaged in bad practices. Scientists should publish work in ways that enrich the scientific community not ways that starve the scientific commons and enrich a few publishers that are doing everything they can to hold back information sharing.

In 2008 Harvard’s liberal arts faculty voted to make their research open source.

The Secret Life of Plankton

Fun video with great shots of exotic ocean life that forms the base of the food chain in the ocean from TED Education.

How do Plants Grow Into the Sunlight?

Plants are extremely competitive in gaining access to sunlight. A plant’s primary weapon in this fight is the ability to grow towards the light, getting just the amount it needs and shadowing its competition. Now, scientists have determined precisely how leaves tell stems to grow when a plant is caught in a shady place.

Hole in the Wall trail, Olympic National Park, Washington, USA by John Hunter

The researchers discovered that a protein known as phytochrome interacting factor 7 (PIF7) serves as the key messenger between a plant’s cellular light sensors and the production of auxins, hormones that stimulate stem growth.

“We knew how leaves sensed light and that auxins drove growth, but we didn’t understand the pathway that connected these two fundamental systems,” says Joanne Chory, professor and director of the Salk’s Plant Biology Laboratory and a Howard Hughes Medical Institute investigator (HHMI provides huge amounts of funding for scientific research). “Now that we know PIF7 is the relay, we have a new tool to develop crops that optimize field space and thus produce more food or feedstock for biofuels and biorenewable chemicals.”

Plants gather intelligence about their light situation—including whether they are surrounded by other light-thieving plants—through photosensitive molecules in their leaves. These sensors determine whether a plant is in full sunlight or in the shade of other plants, based on the wavelength of red light striking the leaves. This is pretty cool; I love to learn about the brilliant strategies that have evolved.

If a sun-loving plant, such as thale cress (Arabidopsis thaliana), the species Chory studies, finds itself in a shady place, the sensors will tell cells in the stem to elongate, causing the plant to grow upwards towards sunlight.

When a plant remains in the shade for a prolonged period, however, it may flower early and produce fewer seeds in a last ditch effort to help its offspring spread to sunnier real estate. In agriculture, this response, known as shade avoidance syndrome, results in loss of crop yield due to closely planted rows of plants that block each other’s light.

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Bacteria In Cave Isolated for 4 Million Years Highly Resistant to Many Antibiotics

PLoS published an interesting open access research paper on bacteria and their resistance to antibiotics. I am surprised how widespread and strong the antibiotic resistance was is the isolated bacteria that were studied. It raises more interesting questions about the important area of antibiotics.

The lead researcher on this study, Gerry Wright, previously published on antibiotic properties of bacteria found in soil.

Abstract of Antibiotic Resistance Is Prevalent in an Isolated Cave Microbiome

Antibiotic resistance is a global challenge that impacts all pharmaceutically used antibiotics. The origin of the genes associated with this resistance is of significant importance to our understanding of the evolution and dissemination of antibiotic resistance in pathogens. A growing body of evidence implicates environmental organisms as reservoirs of these resistance genes; however, the role of anthropogenic use of antibiotics in the emergence of these genes is controversial.

We report a screen of a sample of the culturable microbiome of Lechuguilla Cave, New Mexico, in a region of the cave that has been isolated for over 4 million years. We report that, like surface microbes, these bacteria were highly resistant to antibiotics; some strains were resistant to 14 different commercially available antibiotics. Resistance was detected to a wide range of structurally different antibiotics including daptomycin, an antibiotic of last resort in the treatment of drug resistant Gram-positive pathogens.

Enzyme-mediated mechanisms of resistance were also discovered for natural and semi-synthetic macrolide antibiotics via glycosylation and through a kinase-mediated phosphorylation mechanism. Sequencing of the genome of one of the resistant bacteria identified a macrolide kinase encoding gene and characterization of its product revealed it to be related to a known family of kinases circulating in modern drug resistant pathogens. The implications of this study are significant to our understanding of the prevalence of resistance, even in microbiomes isolated from human use of antibiotics. This supports a growing understanding that antibiotic resistance is natural, ancient, and hard wired in the microbial pangenome.