Butterflies Shed Light on How Some Species Respond to Global Warming

With global warming and climate change making headlines nearly every day, it could be reassuring to know that some creatures might cope by gradually moving to new areas as their current ones become less hospitable. Nevertheless, natural relocation of species is not something that can be taken for granted, according to Jessica Hellmann, Associate Professor at the University of Notre Dame Department of Biological Science in Notre Dame, Ind. By studying two species of butterfly, she and her team have found evidence suggesting that a number of genetic variables affect whether and how well a species will relocate.


Dr. Hellmann and her team have conducted a series of studies in which manipulating the temperature of the butterfly larvae's environment revealed how the two species might respond to global warming. She will discuss the team's work at the 2010 American Physiological Society's Intersociety Meeting in Westminster, Colo., August 4-7. The program is entitled, Global Change and Global Science: Comparative Physiology in a Changing World.

Duskywing and Swallowtail Butterflies: Coping with Change

The Notre Dame team studied the larvae -- or caterpillar phase -- of two butterfly species, the Propertius duskywing butterfly (Erynnis propertius) and the Anise swallowtail butterfly (Papilio zelicaon). These butterflies, both cold-blooded insects, were chosen because of their ecological differences but they live in the same ecosystem, allowing Dr. Hellmann to compare their responses in a single study.

The duskywing is a small butterfly that does not easily fly great distances and stays close to the West Coast of the United States. Because it does not fly great distances, the genetic makeup of the group does not spread very far. The species is also characterized by the fact that its larvae consume only the new leaves of oak trees, making it highly specialized. The Anise swallowtail, on the other hand, is a much larger butterfly, and can fly greater distances with greater ease. Its genes are more likely to be spread out over a larger range as its flies between the Rocky Mountains and westward to and around California. The swallowtail larvae eat an assortment of plants, which also helps to spread genes across its range.

The researchers performed a number of experiments between butterfly larvae from the northernmost ranges of their habitat (Vancouver Island, Canada; "northern larvae") and butterflies from the central part of their habitat (California and southwest Oregon; "central larvae"). They exposed each group of larvae to conditions simulating the other group's summer and winter climates and fed each group food grown in the other group's location, all with a special focus on how the northern larvae responded. According to Dr. Hellmann, understanding how populations at the edge of a species' range respond to warming will provide insight on whether the species will shift with climate change.

The team theorized that northern members of a species whose genes are more spread out, like the swallowtail's, might be pre-adapted to rising temperatures and could perhaps even thrive as the northern climate gets warmer. Conversely, species like the duskytail, whose genes are not as spread out, could be locally adapted to climatic conditions at the edge of the range and northern populations might reduce under climate change.

Either way, it boils down to whether the species in Vancouver would respond positively to their climate becoming more like California's. So far, the answer for both species is "no," for different reasons in each species.

"In summer conditions, the duskywing larvae grew bigger, faster, and they survived better, which suggested that they liked it warmer, but winter was another story," said Dr. Hellmann. "In the warmer winter, they increased metabolism and burned through energy faster. This suggests that they were adapted to the cooler winters of Vancouver."

As for northern swallowtails in central conditions, "They just didn't care," Dr. Hellmann said. "They didn't respond to warming at all. They didn't do better or worse. This means that assumptions about warming possibly benefiting species [with more spread out genes], particularly at the northern edge of the range, are not appropriate."


The Genetic Connection

The team has begun studying the genetic explanation for how the two species respond to warming. They are investigating what genes are responsible for the individualized responses, and will use genomic tools to learn which genes are involved when the species is experiencing climate change, said Dr. Hellmann. "We will also try to determine which genes these butterflies are synthesizing when they experience climate warming. We want to know if northern and southern members of the same species are expressing their genome differently or the same."

The answers may explain the differences between various populations of the same species -- northern vs. central -- and why some species might not be inclined to relocate as the climate heats up.

"Expecting creatures to pick up and move north makes sense theoretically," Dr. Hellmann said. "But the reality is that genetic and physiological interactions are so complicated, it's hard to imagine how it will play out for all species everywhere."

Dr. Hellmann leads the research team comprised of Shannon Pelini, Jason Dzurisin, Shawn O'Neil and Scott Emrich, all of the University of Notre Dame, Notre Dame, IN; and Caroline Williams and Brent Sinclair, of the University of Western Ontario, London, ON, CN. Dr. Hellman will discuss the team's work the conference, Global Change and Global Science: Comparative Physiology in a Changing World, being held

NASA's Great Observatories Witness a Galactic Spectacle

A new image of two tangled galaxies has been released by NASA's Great Observatories. The Antennae galaxies, located about 62 million light-years from Earth, are shown in a new composite image from the Chandra X-ray Observatory (blue), the Hubble Space Telescope (gold and brown), and the Spitzer Space Telescope (red). The Antennae galaxies take their name from the long, antenna-like arms seen in wide-angle views of the system. These features were produced in the collision.


The collision, which began more than 100 million years ago and is still occurring, has triggered the formation of millions of stars in clouds of dusts and gas in the galaxies. The most massive of these young stars have already sped through their evolution in a few million years and exploded as supernovas.

The X-ray image from Chandra shows huge clouds of hot, interstellar gas, which have been injected with rich deposits of elements from supernova explosions. This enriched gas, which includes elements such as oxygen, iron, magnesium and silicon, will be incorporated into new generations of stars and planets. The bright, point-like sources in the image are produced by material falling onto black holes and neutron stars that are remnants of the massive stars. Some of these black holes may have masses that are almost one hundred times that of the sun.

The Spitzer data show infrared light from warm dust clouds that have been heated by newborn stars, with the brightest clouds lying in the overlap region between the two galaxies. The Hubble data reveal old stars and star-forming regions in gold and white, while filaments of dust appear in brown. Many of the fainter objects in the optical image are clusters containing thousands of stars.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.

Quantum Networks

 A team of Harvard physicists led by Mikhail D. Lukin has achieved the first-ever quantum entanglement of photons and solid-state materials. The work marks a key advance toward practical quantum networks, as the first experimental demonstration of a means by which solid-state quantum bits, or "qubits," can communicate with one another over long distances.



Quantum networking applications such as long-distance communication and distributed computing would require the nodes that process and store quantum data in qubits to be connected to one another by entanglement, a state where two different atoms become indelibly linked such that one inherits the properties of the other.


"In quantum computing and quantum communication, a big question has been whether or how it would be possible to actually connect qubits, separated by long distances, to one another," says Lukin, professor of physics at Harvard and co-author of a paper describing the work in the journal Nature.


"Demonstration of quantum entanglement between a solid-state material and photons is an important advance toward linking qubits together into a quantum network."


Quantum entanglement has previously been demonstrated only with photons and individual ions or atoms.


"Our work takes this one step further, showing how one can engineer and control the interaction between individual photons and matter in a solid-state material," says first author Emre Togan, a graduate student in physics at Harvard. "What's more, we show that the photons can be imprinted with the information stored in a qubit."

Quantum entanglement, famously termed "spooky action at a distance" by a skeptical Albert Einstein, is a fundamental property of quantum mechanics. It allows one to distribute quantum information over tens of thousands of kilometers, limited only by how fast and how far members of the entangled pair can propagate in space.


The new result builds upon earlier work by Lukin's group to use single atom impurities in diamonds as qubits. Lukin and colleagues have previously shown that these impurities can be controlled by focusing laser light on a diamond lattice flaw where nitrogen replaces an atom of carbon. That previous work showed that the so-called spin degrees of freedom of these impurities make excellent quantum memory.


Lukin and his co-authors now say that these impurities are also remarkable because, when excited with a sequence of finely tuned microwave and laser pulses, they can emit photons one at a time, such that photons are entangled with quantum memory. Such a stream of single photons can be used for secure transmission of information.


"Since photons are the fastest carriers of quantum information, and spin memory can robustly store quantum information for relatively long periods of time, entangled spin-photon pairs are ideal for the realization of quantum networks," Lukin says. "Such a network, a quantum analog to the conventional internet, could allow for absolutely secure communication over long distances."

Prompting hearts to make their own beating muscle

Beating heart muscle cells have for the first time been made directly from other heart cells. The breakthrough may enable damaged heart muscle to be repaired by converting the structural cells called fibroblasts into the cardiomyocytes that make the heart beat.


The route from fibroblasts to cardiomyocytes is so direct that no transitory stem cells need to be formed in the process, avoiding the extra step by which many other researchers are trying to create heart cells from patients' own cells, or from human embryonic stem cells.

"Other teams, including ours, have spent significant effort making cardiomyoctes from stem cells for regenerative purposes," says Deepak Srivastava of the Gladstone Institute of Cardiovascular Disease in San Francisco.



Change of heart

Now Srivastava and his team have created mouse cardiomyocytes by exposing mouse fibroblasts to three transcription factor proteins called Gata4, Mef2c and Tbx5 that activate genes needed for the formation of embryonic heart tissue. "The fibroblasts started to convert within a few days and continued to make the transition to cardiomyocytes over several weeks, beating at about one month," Srivastava says.

The team also transplanted treated fibroblasts into the hearts of live mice, where they developed into cardiomyocytes.

Next, Srivastava's team will see if the process works on human fibroblasts. They will also hunt for ways to morph fibroblasts without having to first infect them with a virus – which is how the transcription factors were transported to the mouse fibroblasts.



Future therapy

Srivastava suggests that people with heart damage might eventually be treated with stents that release the transcription factors to stimulate the generation of cardiomyocytes from their own fibroblasts.

"The new approach is elegantly simple, to convert the non-muscular components of the heart to cardiac muscle," says Chris Mason, professor of regenerative medicine at University College London.

Mason points out that in a similar approach reported in 2008, Doug Melton and his colleagues at Harvard University showed they could change ordinary mouse pancreas cells into the beta cells that make insulin. "The direct reprogramming strategy may be the best route forward for a number of diseases where cell replacement is impractical," says Mason.

Greenland Glacier Calves Island Four Times the Size of Manhattan

 A University of Delaware researcher reports that an "ice island" four times the size of Manhattan has calved from Greenland's Petermann Glacier. The last time the Arctic lost such a large chunk of ice was in 1962.

"In the early morning hours of August 5, 2010, an ice island four times the size of Manhattan was born in northern Greenland," said Andreas Muenchow, associate professor of physical ocean science and engineering at the University of Delaware's College of Earth, Ocean, and Environment. Muenchow's research in Nares Strait, between Greenland and Canada, is supported by the National Science Foundation (NSF).

Satellite imagery of this remote area at 81 degrees N latitude and 61 degrees W longitude, about 620 miles [1,000 km] south of the North Pole, reveals that Petermann Glacier lost about one-quarter of its 43-mile long [70 km] floating ice-shelf.

Trudy Wohlleben of the Canadian Ice Service discovered the ice island within hours after NASA's MODIS-Aqua satellite took the data on Aug. 5, at 8:40 UTC (4:40 EDT), Muenchow said. These raw data were downloaded, processed, and analyzed at the University of Delaware in near real-time as part of Muenchow's NSF research.

Petermann Glacier, the parent of the new ice island, is one of the two largest remaining glaciers in Greenland that terminate in floating shelves. The glacier connects the great Greenland ice sheet directly with the ocean.

The new ice island has an area of at least 100 square miles and a thickness up to half the height of the Empire State Building.

"The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days," Muenchow said.

The island will enter Nares Strait, a deep waterway between northern Greenland and Canada where, since 2003, a University of Delaware ocean and ice observing array has been maintained by Muenchow with collaborators in Oregon (Prof. Kelly Falkner), British Columbia (Prof. Humfrey Melling), and England (Prof. Helen Johnson).

"In Nares Strait, the ice island will encounter real islands that are all much smaller in size," Muenchow said. "The newly born ice-island may become land-fast, block the channel, or it may break into smaller pieces as it is propelled south by the prevailing ocean currents. From there, it will likely follow along the coasts of Baffin Island and Labrador, to reach the Atlantic within the next two years."

The last time such a massive ice island formed was in 1962 when Ward Hunt Ice Shelf calved a 230 square-mile island, smaller pieces of which became lodged between real islands inside Nares Strait. Petermann Glacier spawned smaller ice islands in 2001 (34 square miles) and 2008 (10 square miles). In 2005, the Ayles Ice Shelf disintegrated and became an ice island (34 square miles) about 60 miles to the west of Petermann Fjord.

latest news and articles on science: New Wall Climbing Robot

latest news and articles on science: New Wall Climbing Robot: " Wielding two claws, a motor and a tail that swings like a grandfather clock's pendulum, a small robot named ROCR ('rocker') scrambles up a ..."

New Wall Climbing Robot

 Wielding two claws, a motor and a tail that swings like a grandfather clock's pendulum, a small robot named ROCR ("rocker") scrambles up a carpeted, 8-foot wall in just over 15 seconds -- the first such robot designed to climb efficiently and move like human rock climbers or apes swinging through trees.


"While this robot eventually can be used for inspection, maintenance and surveillance, probably the greatest short-term potential is as a teaching tool or as a really cool toy," says robot developer William Provancher, an assistant professor of mechanical engineering at the University of Utah.

His study on development of the ROCR Oscillating Climbing Robot is set for online publication this month by Transactions on Mechatronics, a journal of the Institute of Electrical and Electronics Engineers and American Society of Mechanical Engineers.

Provancher and his colleagues wrote that most climbing robots "are intended for maintenance or inspection in environments such as the exteriors of buildings, bridges or dams, storage tanks, nuclear facilities or reconnaissance within buildings."

But until now, most climbing robots were designed not with efficiency in mind, only with a more basic goal: not falling off the wall they are climbing.

"While prior climbing robots have focused on issues such as speed, adhering to the wall, and deciding how and where to move, ROCR is the first to focus on climbing efficiently," Provancher says.

One previous climbing robot has ascended about four times faster than ROCR, which can climb at 6.2 inches per second, but ROCR achieved 20 percent efficiency in climbing tests, "which is relatively impressive given that a car's engine is approximately 25 percent efficient," Provancher says.

The robot's efficiency is defined as the ratio of work performed in the act of climbing to the electrical energy consumed by the robot, he says.

Provancher's development, testing and study of the self-contained robot was co-authored by Mark Fehlberg, a University of Utah doctoral student in mechanical engineering, and Samuel Jensen-Segal, a former Utah master's degree student now working as an engineer for a New Hampshire company.


The National Science Foundation and University of Utah funded the research.

ROCR is a Swinger that Claws Its Way to the Top

Other researchers have studied a variety of ways for climbing robots to stick to walls, including dry adhesives, microspines, so-called "dactyl" spines or large claws like ROCR's, suction cups, magnets, and even a mix of dry adhesive and claws to mimic wall-climbing geckos.

Now that various methods have been tried and proven for robots to climb a variety of wall surfaces, "if you are going to have a robot with versatility and mission-life, efficiency rises to the top of the list of things to focus on," Provancher says.

Nevertheless, "there's a lot more work to be done" before climbing robots are in common use, he adds.

Some previous climbing robots have been large, with two to eight legs. ROCR, in contrast, is small and lightweight: only 12.2 inches wide, 18 inches long from top to bottom and weighing only 1.2 pounds.

The motor that drives the robot's tail and a curved, girder-like stabilizer bar attach to the robot's upper body. The upper body also has two small, steel, hook-like claws to sink into a carpeted wall as the robot climbs. Without the stabilizer, ROCR's claws tended to move away from the wall as it climbed and it fell.

The motor drives a gear at the top of the tail, causing the tail to swing back and forth, which propels the robot upward. A battery is at the end of the tail and provides the mass that is necessary to swing the robot upward.

"ROCR alternatively grips the wall with one hand at a time and swings its tail, causing a center of gravity shift that raises its free hand, which then grips the climbing surface," the study says. "The hands swap gripping duties and ROCR swings its tail in the opposite direction."

ROCR is self-contained and autonomous, with a microcomputer, sensors and power electronics to execute desired tail motions to make it climb.


Provancher says that to achieve efficiency, ROCR mimics animals and machines.

"It pursues this goal of efficiency with a design that mimics efficient systems both in nature and manmade," he says. "It mimics a gibbon swinging through the trees and a grandfather clock's pendulum, both of which are extremely efficient."

The study says: "The core innovations of ROCR -- its energy-efficient climbing strategy and simple mechanical design -- arise from observing mass shifting in human climbers and brachiative [swinging] motion in animals."

Simulating and Testing a Climbing Robot

Before testing the robot itself, Provancher and colleagues used computer software to simulate ROCR's climbing, using such simulation to evaluate the most efficient climbing strategies and fine-tune the robot's physical features.

Then they conducted experiments, varying how fast and how far the robot's tail swung, to determine how to get the robot to climb most efficiently up an 8-foot-tall piece of plywood covered with a short-nap carpet.

The robot operated fastest and most efficiently when it ran near resonance -- near the robot's natural frequency -- similar to the way a grandfather clock's pendulum swings at its natural frequency. With its tail swinging more slowly, it climbed but not as quickly or efficiently.

The researchers found it achieve the greatest efficiency -- 20 percent -- when the tail swung back and forth 120 degrees (or 60 degrees to each side of straight down), when the tail swung back and forth 1.125 times per seconds and when the claws were spaced 4.9 inches apart.

When the tail swung at two times per second, it was too fast and ROCR jumped off the wall, and was caught by a safety cord so it wasn't damaged.

Provancher says the study is the first to set a benchmark for the efficiency of climbing robots against which future models may be compared. He says future work will include improving the robot's design, integrating more complex mechanisms for gripping to walls of various sorts, such as brick and sandstone, and investigating more complex ways of controlling the robot -- all aimed at improving efficiency.

"Higher climbing efficiencies will extend the battery life of a self-contained, autonomous robot and expand the variety of tasks the robot can perform," he says