The brain in the supermarket

Study: Simple “index strategy” helps consumers make choices.

CAMBRIDGE, Mass. -- Say you’re out shopping for basic household goods — perhaps orange juice and soup. Or light bulbs. Or diapers for your young child. How do you choose the products you buy? Is it a complicated decision, or a simple one?

It could be complex: Factors like price, quality, and brand loyalty may run through your mind. Indeed, some scholars have developed complicated models of consumer decision-making, in which people accumulate substantial product knowledge, then weigh that knowledge against the opportunity to explore less-known products.

But in a new paper, MIT researchers suggest that your brain is making a simpler calculation when you shop: You are most likely deploying an “index strategy,” a straightforward ranking of products. It may not be an absolutely perfect calculation, given all the available information, but the study suggests that an index strategy comes very close to being optimal, and is a far easier way for consumers to make their choices.

“The advantage of making a slightly better decision wouldn’t be worth it,” says John Hauser, the Kirin Professor of Marketing at the MIT Sloan School of Management and a co-author of the new study. Rather, he asserts, a simple index strategy “is going to get you really pretty close to an optimal decision at a much lower cost — both search cost and cognitive cost.” Basic rankings help you make quick decisions, and leave room to think about things other than your weekend shopping choices.

Typical models of consumer thought often treat the brain like an always-running computer, and hold that consumers constantly worry about the ways in which their choices interact. For instance: When considering one diaper brand, these models posit that consumers are worried they will lose opportunities to learn more about other brands. The MIT team also believes that consumers accumulate information, but in a simpler, more intuitive way.

“When we look at our options, we normally evaluate them one by one,” says Juanjuan Zhang, an associate professor of marketing at MIT Sloan and another co-author of the study. “We would argue that that is the way we think, and that is different from how other models in marketing work.”

No space for PSPACE

The paper — titled “Learning from Experience, Simply” — is published in the journal Marketing Science. The co-authors are MIT doctoral candidate Song Lin, Zhang, and Hauser.

The study described in the paper is explicitly intended to bridge the gap between empirical studies of consumer decision-making and mathematical models in the field. Hauser, Lin, and Zhang suggest that some models of consumer thought are “PSPACE-hard” — that is, so mathematically difficult as to be virtually unsolvable even with the fastest computer, where the number of steps needed to find a solution is a direct function of the problem’s size. 

“They’re assuming consumers can make decisions that computers can’t solve,” Hauser says. “And they’re assuming consumers make these in seconds as they walk down the aisle in the supermarket.” Besides, he notes, “Even a computer uses simple heuristics to solve these problems.”

To test whether an index strategy reasonably describes how consumers think, Lin, Zhang, and Hauser conducted an empirical study of consumers who purchase diapers, using a commercial data set of 262 households and almost 3,400 purchases, which turned up several relevant patterns, such as the fact that consumers are more likely to change diaper brands within their first 13 purchases.

To the researchers, this suggests that consumers are learning, and valuing the opportunity to switch — while the data fits the concept of the index strategy. It explains product choices as well as other models, while showing how consumers may be inclined to reduce their thinking costs in terms of time. 

“If we assume consumers are using this heuristic, it explains the data just as well as the optimal [models] do,” Hauser says.

A place where you’d expect learning

At the same time, the idea of the index strategy does not rule out consumer reassessment of brands. Studying a product like diapers, the researchers note, shows that people do learn some new information about products, and sometimes flip their index rankings as a consequence.

Thus the results of index strategies resemble those of complex models, but arrive there in a much more direct way.
“Two things about diapers make it a good category,” Hauser says. “One is that we can identify people who are new, or haven’t been in the category for a while. … It’s a place where you’d expect learning. The other thing is, learning about diapers is probably pretty important to new parents. There are incentives to learn.”

For their part, the researchers say they are open to further studies, and hope to get empiricists and theorists of consumer cognition to “talk to one another” to an increasing extent. The supermarket aisle, after all, is not the only spot where we can expect learning to take place.


Written by Peter Dizikes, MIT News Office

Related links

ARCHIVE: Why let your sales force influence product prices?
 http://newsoffice.mit.edu/2014/why-let-your-sales-force-influence-product-prices-0730
ARCHIVE: Observing the observers
http://newsoffice.mit.edu/2013/observing-the-observers-0106

Massachusetts Institute of Technology, 77 Massachusetts Avenue Building 11-400, Cambridge, MA 02139-4307 United States

Good Bone, Bad Bone

Scientists explore a new parameter of bone quality that measures strength instead of density
By Julie Cohen

For people taking glucocorticoids such as prednisone, the increased risk of bone fracture is a well-documented side effect. Used to treat a variety of medical conditions, including autoimmune diseases and allergies, glucocorticoids are known to cause rapid deterioration in bone strength.

UCBS professor Paul Hansma holds
the Osteprobe which he co-invented
with physics colleagues Connor Randall
and Daniel Bridges;
Photo Credit:Spencer Bruttig

Until now, doctors have been able to measure bone loss — a process that happens slowly, over time — but haven’t had the means for gauging actual bone strength. That has changed thanks to a new hand-held instrument developed in the Hansma Lab at UC Santa Barbara. Called the OsteoProbe, the device uses reference point indentation (RPI) to measure mechanical properties of bone at the tissue level.

A new clinical trial, conducted at the Hospital del Mar in Barcelona, Spain, shows that RPI is sensitive enough to reflect changes in cortical bone indentation following treatment with osteoporosis therapies in patients newly exposed to glucocorticoids. Standard measurement techniques were unable to detect bone changes in this patient population. The trial results are reported in the Journal of Bone and Mineral Research.

“This new paper is a real breakthrough because it’s the first time it’s been possible to do a longitudinal study of bone material properties in patients,” said co-author Paul Hansma, professor emeritus in UCSB’s Department of Physics. “Up until now, medical professionals have been limited to doing bone mineral density studies, which can take a year or more to show bone changes.”

According to Hansma, measuring bone mineral density (BMD) using today’s standard, dual X-ray absorptiometry (DXA) provides only a partial picture. “DXA measures density, which sounds like a material property but isn’t,” he said. “DXA measures how much calcium bone contains but provides no information about bone quality, and it’s not just how much bone you have that’s important, it’s how good that bone is.”The OsteoProbe works similarly to a center punch — the tool that makes a slight indentation on a surface to indicate the correct placement of a nail. It sets a localized reference point at the bone’s surface that enables precise indentation measurements of bone strength. It was developed by Hansma and colleagues Connor Randall and Dan Bridges, staff research associate and development assistant engineer, respectively, in UCSB’s Department of Physics.

The instrument is now manufactured for commercial research applications by ActiveLife Scientific, a Santa Barbara company founded by UCSB graduates Davis Brimer and Alex Proctor. Brimer and Proctor won the campus’s annual New Venture Competition in 2007 and used the $10,000 prize as startup capital.

About the device

The OsteoProbe measures the bone material strength index (BMSi), which in previously published papers has been shown to be a valuable predictor of bone fracture risk. The index values are similar to percentage scores on an exam. A BMSi of 90 or greater is excellent, 80 to 90 good, 70 to 80 fair, 60 to 70 poor and below 60 very poor. 

A study conducted at the Mayo Clinic in Rochester, Minnesota, demonstrated the device’s ability to successfully detect bone quality deterioration in diabetic patients, independent of BMD. In another study conducted at Leiden University in the Netherlands, the tool successfully distinguished between patients with and without fracture, not only in patients with osteoporosis but also in those with osteopenia, the precursor to osteoporosis.

“Bone fracture is becoming more and more of a serious problem as people live longer,” Hansma said. “It’s exciting that it’s now possible to measure BMSi in living patients and hopefully this can guide physicians in the future in choosing appropriate therapies to prevent bone fracture, especially in elderly people.”

Research is ongoing

Exactly how the BMSi relates to the specialized quantities measured by conventional mechanical testing is a focus of current research. In fact, in a recent paper published in the Journal of the Mechanical Behavior of Biomedical Materials, UCSB Chancellor Henry T. Yang and two of his graduate students used finite element analysis to investigate the link between BMSi and the mechanical properties of bone itself.

“What’s new in this paper is the ability to correlate indentation measurements from patients’ bones to computer simulations that can predict the strength of the bones,” said Yang, who is also a professor of mechanical engineering. “Such predictions are based on the measured material properties of the bone samples. The results open the door to clinical applications in diagnosis and monitoring, in performing orthopedic surgeries and in developing new therapies.”

The paper’s lead author, Kevin Hoffseth, a graduate student in the Department of Mechanical Engineering, noted that the study results suggest RPI could become an integral part in linking clinical results to the mechanical properties of bone related to its health. “Combining theory and experiment with finite element simulations and indentation testing was an effective approach to study bone indentation and failure — and the link to mechanical properties,” he said.

Clinical trials currently underway in some 20 locations are exploring bone health in a variety of ways. One European study is comparing the bone quality of patients in Norway to that of patients in Spain. People in Norway tend to have higher BMD and a greater frequency of fracture than do people in Spain, Hansma noted.

 “That’s the opposite of what it should be if BMD were all that mattered,” he added. “So that means that BMD isn’t all that matters and the hope is that this instrument will reveal the difference in the BMSi between patients in Norway and in Spain.”

Hansma posited that such medical bone diagnostics could become an important feature of future therapeutic treatments. “Now that it is possible to measure whether bone is good or bad in research studies, we can begin learning what diet, exercises, vitamins and pharmaceutical drugs contribute to making bone good,” he said. “After the OsteoProbe gets FDA approval, individual physicians will be able to use it to help them decide about the best therapeutic treatments for their patients.”

Contact Info: 

Julie Cohen
julie.cohen@ucsb.edu
(805) 893-7220

New insights into the mysterious ocean floor

Marine scientists from Kiel present new concepts of the formation of mud volcanoes and cold seeps in the deep sea

With help of the AUV ABYSS (top right) the mud volcanoes
Abzu, Tiamat and M. Ivanov have been discovered in 2012.
Photo/Graphic Credit: GEOMAR

24 March 2015/Kiel. During an expedition of the German research vessel METEOR in 2012 scientists of the GEOMAR Helmholtz-Centre for Ocean Research Kiel together with colleagues from Bremen and Halle, Portugal, Spain and the UK, discovered previously unknown mud volcanoes on the seabed of the Atlantic Ocean. In the international journal Geology they now show, why the structures provide new insights about the processes below the seafloor – and why they simultaneously raise new questions.


For the ancient Babylonians Abzu and Tiamat were the gods of fresh- and saltwater. For today’s ocean sciences two mud volcanoes of the same names could serve as a key to the understanding of previously undiscovered processes underneath the ocean floor. The two cones are located about 200 kilometers southwest of Portugal, in about 4500 meters water depth at the bottom of the Atlantic Ocean. They were discovered together with a third mud volcano, named after the late Russian scientist “Michael Ivanov” during an expedition of the German research vessel METEOR in 2012. “The mud volcanoes were found in an atypical location. Additionally, further analysis showed that fluids expelled at the seabed in these places has a much deeper  origin than at most other mud volcanoes," says Dr. Christian Hensen, geologist with the GEOMAR Helmholtz Centre for Ocean Research Kiel and chief scientist of the 2012 expedition. Together with colleagues from the UK, Spain, Portugal and the Universities of Bremen and Halle he now presents the results of the investigations in the international journal Geology.

Mud volcanoes are morphological structures where fluids, including water and gases, are released from the subsurface. “Sometimes cones emerge during this process, which appear as small-scale volcanoes”, explains Dr. Hensen. They are found at nearly all continental slopes and they often occur on thick sedimentary deposits, for example at large deep-sea fans such as the Nile Delta, where huge amounts of sediments have accumulated over the millennia. A large number of mud volcanoes are known from the Gulf of Cadiz south of Portugal and Spain, where they have formed on thick sedimentary sequences that have been partly thrusted by movements of the earth’s crust. “But Abzu, Tiamat and M. Ivanov are not situated on this so-called accretionary wedge. They are located further west near a fracture zone along the African-Eurasian plate boundary. Before our expedition took place, we only hypothesized about the existence of mud volcanoes in this area. Now we have the proof," says Dr. Hensen.

The research team aboard the METEOR mapped the volcanoes with the autonomous underwater vehicle (AUV) ABYSS and then sampled it with gravity corers. Later scientists analyzed the samples precisely in the laboratories of the participating institutions. The results were surprising. “Usually gases and fluids emerging from mud volcanoes are only derived from the sediments below. The material coming out of these three mud volcanoes also refers to a source in the crust underneath the sediments," explains Dr. Hensen.

This brought up a new set of questions for further research: What are the exact subsurface mechanisms feeding the mud volcanoes?  Where do other seeps of this type exist? “We know hot vents at mid-ocean ridges, where new crust is formed. These places are relatively easy to find, because almost no sediments are lying on top of the crust, the ascent rates of the fluids are high, and due to the chemical composition of the fluids conspicuous traces on the sea floor are formed, for example the famous Black Smokers,” says Dr. Hensen. There may be similar processes in other areas of the seabed, especially near fracture zones. “The newly discovered mud volcanoes are a clear indication that this conjecture is true", he adds. However, it is more difficult to find these systems with increasing distance from the mid-ocean ridges, because they become less dynamic and the sediment thickness increases.

The current publication is an important basis for further research projects, which should help to better understand the mechanisms of fluid transport in the seabed. During the recent expedition of the new German research vessel SONNE (SO237) the sea floor of the Atlantic Ocean along a prominent facture zone was mapped again by the AUV ABYSS to get more data for future projects. The knowledge about hot and cold springs at the seafloor, their formation mechanisms, and their supply routes is important for a better understanding of specific plate tectonic processes and related earthquake risks.

“The ancient Babylonians presumed a large, hidden freshwater ocean under the salt water ocean Tiamat, whom they called Abzu. Mud volcanoes connect the ocean with the underground of the seafloor, which is still mysterious to us, and, in many cases, they release freshwater. Therefore, we found the names very appropriate for these important discoveries”, says Dr. Hensen.


Reference:
Hensen, C., F. Scholz, M. Nuzzo, V. Valadares, E. Gràcia, P. Terrinha, V. Liebetrau, N. Kaul, S. Silva, S. Martínez-Loriente, R. Bartolome, E. Piñero, V.H. Magalhães, M. Schmidt, S.M. Weise, M. Cunha, A. Hilario, H. Perea, L. Rovelli and K. Lackschewitz (2015): Strike-slip Faults Mediate the Rise of Crustal-Derived Fluids and Mud Volcanism in the Deep Sea. Geology, http://dx.doi.org/10.1130/G36359.1

Links:
www.geomar.de GEOMAR Helmholtz Centre for Ocean Research Kiel
www.flows-cost.eu The project FLOWS (Impact of Fluid circulation in old oceanic Lithosphere on the seismicity of transfOrm-type plate boundaries: neW solutions for early seismic monitoring of major European Seismogenic zones)


Contact:
Jan Steffen (GEOMAR, Communication & Media), Tel.: (+49) 0431 600-2811, presse@geomar.de 
 

GEOMAR
Helmholtz-Zentrum für Ozeanforschung Kiel

Wischhofstr. 1-3, Geb. 4

24148 Kiel
GERMANY

Report reveals alarming lack of water, sanitation and hygiene in health care facilities

Report reveals alarming lack of water, sanitation and hygiene in health care facilities

WHO and UNICEF call for immediate action on improving sanitation in low- and middle-income countries; UNC-Chapel Hill researchers author report

(Chapel Hill, N.C.—March 23, 2015) –The World Health Organization and UNICEF have commissioned the first comprehensive, multi-country analysis on water, sanitation and hygiene (WaSH) services in health care facilities, calling for global action to push toward 100 percent coverage of these services through new policies, collaboration, monitoring and training.

The report, released March 17, evaluated available WaSH data from 66,101 health-care facilities in 54 low- and middle-income countries and found that 38 percent of those facilities lack an improved water source, 19 percent lack improved sanitation, and 35 percent lack soap for hand washing – situations that impede even basic health-care services such as child delivery.

The report’s authors are Jamie Bartram, director of The Water Institute at the University of North Carolina at Chapel Hill and Don and Jennifer Holzworth Distinguished Professor in the department of environmental sciences and engineering, and Ryan Cronk, doctoral student in environmental sciences and engineering.

“It is shameful that there are health care facilities failing to provide a safe environment, compromising the health of those who turn to them for care,” Bartram said. “We need health-care professionals—from the health worker in charge of the smallest health post to the CEO of the most sophisticated hospital—to take responsibility for delivering on the medical maxim ‘first do no harm.’”
 

Lack of water, sanitation and hygiene services in health-care facilities causes infection risk within the very institutions to which patients have come to expect healing. Without WaSH services, patients are put at risk of infection unnecessarily and often have to exit the facility to obtain a drink of water or to relieve themselves. Furthermore, staff members lose an important opportunity to demonstrate safe sanitation and hygiene practices that can improve community habits and health.

Improvements to services can and should begin immediately, the report said, and will require leadership from the health sector, technical advice from water and sanitation experts, and political commitment from governments.

Note: The report is available online at http://www.who.int/water_sanitation_health/en.

-Carolina-

UNC-Chapel Hill contact: Katie Hall, (919) 966-7302 or mchall@email.unc.edu.

World Health Organization contact: Nada Osseiran, osseirann@who.int

UNICEF contact: Fabrice Fotso, +221 33 869 5858, Ext. 265

UNC Office of Communications and Public Affairs • Whitehead Building • 101 McCauley Street, Chapel Hill, NC 27514 • Main: (919) 962-4515 24/7 Media: (919) 445-8555 • email: mediarelations@unc.edu

Glad to Be Home

Anthropologists study the hormonal basis of affiliation and competition among hunters in the Bolivian Amazon
By Andrea Estrada

Absence, it seems, really does make the heart grow fonder.

Tsimane family, Photo Credit: Adrian Jaeggi

That’s according to research conducted by UC Santa Barbara anthropologists, who found that levels of the “love” hormone oxytocin increases among Tsimane men when they come home to their families after a day of hunting. The researchers also found that the increase in oxytocin was greater for those men who were absent longer, and it positively correlated with changes in testosterone. Their findings are published in the Royal Society journal Biology Letters.

The Tsimane are an indigenous population of forager-farmers and hunters who live in the lowlands of Bolivia’s Amazon basin, and the human hormone system should be particularly well adapted to their lifestyle — small, tight-knit communities that produce their own food.

Adrian Jaeggi,
Photo Credit: Rod Rolle

“Our goal was to look at the interaction between different hormones in motivating behavior in a naturalistic context,” said Adrian Jaeggi, the paper’s co-lead author and a postdoctoral scholar in UCSB’s Department of Anthropology. “Hunting for subsistence and sharing meat is something people have done for hundreds of thousands of years.”
With previous studies having shown that oxytocin makes people more cooperative while testosterone has the opposite effect, Jaeggi said he expected to see a trade-off between the two hormones and was surprised to find the positive relationship between them.

An Emotional Balance

According to Jaeggi and co-lead author Ben Trumble, also a postdoctoral scholar at UCSB, high testosterone while hunting could be attributed to a “winner effect” experienced by men making a kill, as shown in previous research by Trumble and colleagues. Additionally, it could be related to the status competition that hunting represents for traditional societies such as the Tsimane. In either case, the concurrently increased oxytocin could serve as a balance to make the hunters kinder, more generous and more willing to share their bounty.

Ben Trumble,
Photo Credit: Adrian Jaeggi

“Almost half a century ago, it was famously documented that successful !Kung hunters were jokingly insulted by others in order to ‘cool their hearts’ to ‘make (them) gentle,’ lest pride or boasting disrupt the egalitarian social system common to many foragers,” said senior co-author Michael Gurven, professor of anthropology at UCSB and co-director of the Tsimane Health and Life History Project. “Here we observe a potential hormonal analogue consistent with the type of leveling behavior seen in hunter-gatherer societies.”

An additional function of both hormones may have to do with post-hunt regeneration. Both are shown to assist with muscle rebuilding following physical activity. “These men are coming home, they’re finished with work for the day, and they’re about to eat and share food,” Jaeggi continued. “So the need to be social coincides with the need to regenerate and it would make sense for the same hormones to facilitate both functions.”

To conduct the study, Trumble joined the hunters as they went out into the jungle and made a kill — or didn’t — and returned home with — or without — food for their families. Trumble took saliva specimens along the way, collecting them at exact intervals. The oxytocin was measured in the UCSB Human Biodemography Laboratory.

Though the sample size is “not huge,” he and Jaeggi noted, the study “definitely adds to the current literature in which the interplay between testosterone and oxytocin is often overlooked.” More than anything else, the sample size is a function of the cost of the lab assays needed to measure the oxytocin. “One of our plans is to develop our own assay to make it less expensive so we can analyze much larger samples,” Jaeggi said.

Home Sweet Home

So how can the findings among a group of indigenous hunter-gatherers in central Bolivia be applied to modern Western culture? “I think the ‘absence makes the heart grow fonder’ effect could potentially be very widespread,” said Jaeggi. “Reconnecting with their families after a day of separation would have been a very common challenge for men throughout evolutionary history, and oxytocin could help with that. Another interesting correlation, Trumble noted, is that the average Tsimane hunt lasts eight and a half hours, roughly equivalent to a workday here.

Other research on oxytocin has shown its value as a means of quantifying the depth of interpersonal relationships. “Oxytocin levels indicate how much you value another person,” said Jaeggi. “It’s like a physiological measure of the value of that relationship.” For example, fall in love with someone and your oxytocin level will skyrocket whenever your sweetheart is near, both literally and figuratively. “Even talking to someone on the phone is enough to cause that oxytocin increase,” he continued.

Of course, men are not the sole beneficiaries of oxytocin’s positive effects. “Like the biology of most social behaviors, it originated in the mother-infant context, where it facilitates giving birth, nursing and bonding,” Jaeggi explained. “It is found in all mammals, and it then got used in other contexts in some species.”

One finding that surprised the researchers involved the correlation of social variables to oxytocin increase: There was none. “I would have expected that men who have more children experience a greater increase when they come home because they’re about to see their families,” said Jaeggi. “Or the guys who encounter people on the way home and get to show off their hunting skills — none of these things had an effect on the oxytocin change. The magnitude of the increase didn’t differ in relation to these social variables.”

Continuing Studies

Jaeggi and Trumble are careful to point out that an inherent problem in their research has to do with the fact that oxytocin has two distinct release systems: one in the brain and one in the rest of the body. Therefore, their measure of oxytocin circulating in the blood may not correspond to levels in the brain. “Some of the social effects of oxytocin might be happening in the brain and we aren’t necessarily capturing that with the saliva sample,” Jaeggi explained. “Of course in this kind of study, all we can do is measure peripheral oxytocin. Measuring oxytocin in the brain would be highly invasive.”

According to Trumble, oxytocin studies in the U.S. often make use of nasal sprays to administer the hormone. “There’s a set of tissues right where arteries meet the brain called the blood-brain barrier. Any molecule above a certain size can’t pass through it,” he explained. “But there’s a weakness in the blood-brain barrier in the nasal canal and allows some transfer to occur. So many experimental studies of oxytocin don’t actually measure oxytocin levels at all, but take instead administer oxytocin and examine before-and-after changes in behavior.”

The researchers added, however, that a particular strength of their work is their ability to study the endogenous levels that are changing naturally rather than from experimental administration. “With the nasal spray, people are getting really large concentrations of oxytocin — it can increase their circulating levels to over 100 times the normal physiological levels,” Jaeggi said. “And if there’s a change in behavior, it’s not the body itself that’s producing the changes.”

Just as significant, Jaeggi and Trumble noted, is their focus on the interaction of the two hormones. “Most researchers tend to look at oxytocin or testosterone one at a time,” Trumble said. “But the endocrine system is really complex and interconnected, so understanding how changes in testosterone impacts oxytocin and vice versa is really important.”

As running laboratory analyses such as those in this study become more affordable — and also become more popular in the scientific literature — researchers will be closer to unlocking some of the secrets of the brain and human behavior in ways not previously possible, particularly with the current model of studying one hormone at a time. “One of the keys to the future of really understanding human behavior is going to be looking at a whole host of hormones together, all at the same time,” Trumble said, “and starting to understand those complicated interactions.

This study was co-authored by Hillard Kaplan, professor of anthropology at the University of New Mexico.

Contact Info: 

Andrea Estrada
andrea.estrada@ucsb.edu
(805) 893-4620

Waiting patiently for Philae

Perhaps it is still too cold for the Philae lander to wake up on Comet 67P/Churyumov-Gerasimenko. Maybe its power resources are not yet sufficient to send a signal to the team at the German Aerospace Center (Deutsches

View of the Lander Control Center at
DLR Cologne, Copyright: DLR Cologne

Zentrum für Luft- und Raumfahrt; DLR) Lander Control Center. On 12 March 2015, the Rosetta orbiter began to send signals to the lander and listen for a response, but Philae has not yet reported back. "It was a very early attempt; we will repeat this process until we receive a response from Philae," says DLR Project Manager Stephan Ulamec. "We have to be patient." On 20 March 2015 at 05:00 CET, the communication unit on the Rosetta orbiter was switched off. Now, the DLR team is calculating when the next favourable alignment between the orbiter and the lander will occur, and will then listen again for a signal from Philae. The next chance to receive a signal from the lander is expected to occur during the first half of April.

After it landed on Comet 67P/Churyumov-Gerasimenko on 12 November 2014, Philae operated continuously for 54 hours; all 10 instruments were used and sent data back to Earth. Then, the lander’s battery was exhausted and Philae went into hibernation at its rather shadowed location. Now, it needs an internal temperature above minus 45 degrees Celsius and at least five watts of power to automatically turn on. Until it can generate a total of 19 watts, it cannot send signals to Earth via the orbiter. For the months of January and February, the engineers at DLR could definitely rule out the ending of hibernation: "Our simulations clearly showed that Philae would still be too cold to reawaken," says Koen Geurts, a member of the control room team at DLR. The engineers saw a first, albeit early, chance in March, when the comet and the lander would be about 300 million kilometres from the Sun – and the amount of solar radiation had nearly doubled when compared to the previous November.

Favourable conditions and new commands

The lander team at DLR is planning the next attempt to communicate with Philae in April. For this, the orbiter must be in a suitable orbital configuration and range with respect to the lander to allow contact. In addition, Philae must be exposed to sunlight and be generating sufficient power to listen for the signal from the orbiter and be able to respond. “These conditions must last for at least 45 minutes, because Philae only operates its receiver every 30 minutes after awakening," explains Geurts.

Waking might be more likely in April, because the team at the Lander Control Center has sent new command sequences to Philae six times, with the primary purpose of instructing the lander to most effectively divide the available solar power between heating and communications. The last time the lander was instructed was on 17 March 2015 at 12:30 UTC, using 'blind commanding' to optimise its energy usage. "We are sure that the communication unit on the orbiter worked, but whether Philae has received the new commands, we do not yet know," says Geurts. It could be that the lander is already awake but does not yet have enough power to transmit a response; in this case, Philae could still receive the commands and execute them.

By the summer, when the comet is much closer to the Sun, the team is hoping to see signs of life from the lander and to receive data regarding the condition of Philae. What is the internal temperature of the lander? Are all its systems working correctly or has the hibernation at very low temperatures had unwanted consequences? How much solar radiation, and thus power, is it receiving? Is the battery charging? After the data is carefully evaluated to determine the 'health' of Philae, the plan is to begin using its instruments and shift work in the DLR Lander Control Center will resume. Once the lander is awake, it will carry out its tasks – Geurts is certain: "Philae is in an optimal location for surviving on the comet."

Contacts:

Manuela Braun 
German Aerospace Center (DLR) 
Corporate Communications
Editor, Human Space Flight, 
Space Science, Engineering 
Tel.: +49 2203 601-3882 
Fax: +49 2203 601-3249 
mailto:Manuela.Braun@dlr.de 

Dr Stephan Ulamec 
German Aerospace Center (DLR) 
Microgravity User Support Center (MUSC)
Space Operations and Astronaut Training 
Tel.: +49 2203 601-4567 
mailto:Stephan.Ulamec@dlr.de 

Dr Koen Geurts 
German Aerospace Center (DLR) 
Space Operations and Astronaut Training 
Tel.: +49 2203 601-3636 
mailto:Koen.Geurts@DLR.de 

VII. Swiss International Summer University on Renewables, ISUenergy 2015

The ISU^energy organizing committee is designing the already 7^th International Summer University on Renewable Energies, the ISU^energy 2015.
This summer university is an internationally established event since 2009.

The ISU^energy2015 will take place from Aug. 23^rd - Sept. 4^th 2015 in Falera/Switzerland.
Excellent Master, Diploma, and PhD students from all over the world from different disciplines are invited to participate in this two-week event.
The interdisciplinary summer university focuses among other topics on

• Photovoltaics
• Solar architecture/BIPV
• Electro-mobility
• Solar thermal aspects
• Smart grids
• Economic and political aspects.

These topics will be treated in lectures, evening talks, practical workshops, and group projects.

The ISU^energy2015 provides a unique setting for students to enrich their knowledge on energy topics. Splendid network opportunities among the students and with the lecturers will be offered.
You can find more information on ISU^energy 2015 costs, accommodation etc. under http://www.helmholtz-berlin.de/events/isu-energy/

Applications are invited from March 1^st until July 5^th, 2015. Simply follow the link http://www.helmholtz-berlin.de/events/isu-energy/applications/ to submit your applications.Early bird fee applications will be valid before May 15^th, 2015, only.

Please feel free to advertise the ISU^energy 2015 by posting it and by forwarding this mail to any parties that might be interested in participating in the ISU^energy 2015.
Thank you.

If you should have any questions, you are always welcome to contact us for more information: isue@helmholtz-berlin.de .

Best regards,
ISU^energy 2015 Team

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V.
Aufsichtsrat: Vorsitzender Prof. Dr. Dr. h.c. mult. Joachim Treusch, stv. Vorsitzende Dr. Beatrix Vierkorn-Rudolph
Geschäftsführung: Prof. Dr. Anke Rita Kaysser-Pyzalla, Thomas Frederking

Sitz Berlin, AG Charlottenburg, 89 HRB 5583

Postadresse:
Hahn-Meitner-Platz 1
D-14109 Berlin

http://www.helmholtz-berlin.de