False memories prime immune system for future attacks

IN A police line-up, a falsely remembered face is a big problem. But for the body's police force – the immune system – false memories could be a crucial weapon.

When a new bacterium or virus invades the body, the immune system mounts an attack by sending in white blood cells called T-cells that are tailored to the molecular structure of that invader. Defeating the infection can take several weeks. However, once victorious, some T-cells stick around, turning into memory cells that remember the invader, reducing the time taken to kill it the next time it turns up.

Conventional thinking has it that memory cells for a particular microbe only form in response to an infection. "The dogma is that you need to be exposed," says Mark Davis of Stanford University in California, but now he and his colleagues have shown that this is not always the case.

The team took 26 samples from the Stanford Blood Center. All 26 people had been screened for diseases and had never been infected with HIV, herpes simplex virus or cytomegalovirus. Despite this, Davis's team found that all the samples contained T-cells tailored to these viruses, and an average of 50 per cent of these cells were memory cells.

The idea that T-cells don't need to be exposed to the pathogen "is paradigm shifting," says Philip Ashton-Rickardt of Imperial College London, who was not involved in the study. "Not only do they have capacity to remember, they seem to have seen a virus when they haven't."

So how are these false memories created? To a T-cell, each virus is "just a collection of peptides", says Davis. And so different microbes could have structures that are similar enough to confuse the T-cells.

To test this idea, the researchers vaccinated two people with an H1N1 strain of influenza and found that this also stimulated the T-cells to react to two bacteria with a similar peptide structure. Exposing the samples from the blood bank to peptide sequences from certain gut and soil bacteria and a species of ocean algae resulted in an immune response to HIV (Immunology, doi.org/kgg).

The finding could explain why vaccinating children against measles seems to improve mortality rates from other diseases. It also raises the possibility of creating a database of cross-reactive microbes to find new vaccination strategies. "We need to start exploring case by case," says Davis.

"You could find innocuous pathogens that are good at vaccinating against nasty ones," says Ashton-Rickardt. The idea of cross-reactivity is as old as immunology, he says. But he is excited about the potential for finding unexpected correlations. "Who could have predicted that HIV was related to an ocean algae?" he says. "No one's going to make that up!"

This article appeared in print under the headline "False memories prime our defences"

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Meteor strike in Russia hurts almost 1,000

MOSCOW: A plunging meteor which exploded with a blinding flash above central Russia , set off a shockwave that shattered windows and hurt almost 1,000 people in an event unprecedented in modern times.

Experts insisted the meteor's fiery entry into the atmosphere on Friday was not linked to the asteroid 2012 DA 14, which later passed about 17,200 miles (27,700 kilometres) above the Earth without incident in an unusually close approach.

But the extraordinary event brought morning traffic to a sudden halt in the Urals city of Chelyabinsk as shocked drivers stopped to watch the falling meteor partially burning up in the lower atmosphere and light up the sky.

The fall of such a large meteor estimated as weighing dozens of tonnes was extremely rare, while the number of casualties as a consequence of its burning up around a heavily-inhabited area was unprecedented.

Chelyabinsk regional governor Mikhail Yurevich, quoted by the RIA Novosti news agency, said 950 people were injured, with two-thirds of the injuries light wounds from glass shards and other materials blown out by the shockwave.

Windows were shattered by the shockwave across the city's region with the ministry saying almost 300 buildings were damaged including schools, hospitals, a zinc factory and even an ice hockey stadium.

"At 9:20 am (0320 GMT), an object was observed above Chelyabinsk which flew by at great speed and left a trail behind. Within two minutes there were two bangs," regional emergencies official Yuri Burenko said in a statement.

The office of the local governor said that a meteorite had fallen into a lake outside the town of Chebarkul in the Chelyabinsk region and television images pointed to a six-metre (20-foot) hole in the frozen lake's ice.

However it has yet to be finally confirmed if meteorite fragments made contact with the Earth and there were no reports that any locals had been hurt directly by a falling piece of meteorite.

Schools were closed for the day and theatre shows cancelled across the region after the shock wave blew out windows amid temperatures as low as minus 18 degrees Celsius (zero degrees Fahrenheit).

"Thank God that nothing fell onto inhabited areas," President Vladimir Putin said in a meeting with Emergencies Minister Vladimir Puchkov, ordering him to look into how to warn citizens about such events.

'A large object weighing tonnes'

The Russian Academy of Sciences said in a statement that it estimated the body to be several metres long and weighing several dozen tonnes. "It burned up at a height of 30-50 kilometres... but pieces could have fallen to Earth as meteorites."

The meteor explosion appears to be one of the most stunning cosmic events above Russia since the 1908 Tunguska Event, when a massive blast most scientists blame on an asteroid or a comet impact ripped through Siberia.

"I am scratching my head to think of anything in recorded history when that number of people have been indirectly injured by an object like this... it's very, very rare to have human casualties," Robert Massey, deputy executive secretary of Britain's Royal Astronomical Society (RAS), told AFP.

But he stressed that he saw "absolutely no connection" between the Chelyabinsk event and asteroid 2012 DA 14.

Live images from a telescope at the Gingin Observatory in western Australia showed the asteroid looking like a white streak.

The time of closest approach was about 2:25 pm EST (1925 GMT), said the US space agency NASA, which had called the event "the closest-ever predicted approach to Earth for an object this large."

NASA estimates an asteroid such as 2012 DA 14 flies close to Earth every 40 years on average, but only hits our planet once every 1,200 years.

Paul Chodas, a research scientist in the Near Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, California, called the meteor-asteroid combination an "incredible coincidence."

Chodas said it was "virtually impossible" to spot objects such as the meteor that struck Russia, which he called a "tiny asteroid", ahead of time against a daytime sky.

With the meteor quickly a leading trend on Twitter, locals posted amateur footage on YouTube showing men swearing in surprise and fright, and others grinding their cars to a halt.

"First I thought it was a plane falling, but there was no sound from the engine... after a moment a powerful explosion went off," witness Denis Laskov told state television.

The Chelyabinsk region is Russia's industrial heartland, filled with smoke-chugging factories and other huge facilities that include a nuclear power plant and the massive Mayak atomic waste storage and treatment centre.

A spokesman for Rosatom, the Russian nuclear energy state corporation, said that its operations remained unaffected.

The emergencies ministry said radiation levels in the region also did not change and that 20,000 rescue workers had been dispatched to help the injured and locate those requiring help.

- AFP/ck

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With Microsoft as tablet rival, will HP go Android?

First a Chromebook, next an Android tablet?

(Credit:
Hewlett-Packard)

If Hewlett-Packard introduces an Android tablet, the newfound rivalry with Microsoft will be one motivating factor, according to analysts.

"I can see why they would go down this route instead of sticking with Microsoft for everything," said Ben Bajarin, a principal at Creative Strategies.

That may be putting it charitably. "[PC makers] are pissed off at Microsoft. That's the general mood," said Roger Kay, principal analyst at Endpoint Technologies, referring to Microsoft's entry into the PC/tablet market with Surface.

Surface practically precluded HP from coming out with a Windows RT tablet based on an ARM chip -- the same silicon used for
Android devices -- Kay said.

In fact, HP scuttled plans last year to bring out an RT
tablet and then dissed Microsoft's device publicly, calling it "slow...kludgy" and "expensive."

But that of course isn't the only reason HP would do an Android tablet. It could, for instance, try to take the lead in bringing Android tablets to large corporate customers, Bajarin said.

To some extent, Samsung is doing that in phones now, but HP, being the largest PC maker in the world, could spearhead Android for business, according to Bajarin. "They could see that as a big opportunity," he said.

And being late to the Android market isn't all bad. "All the development in Android up to this point accrues so they can claim to be on board without a whole lot of development that they have to do independently," Kay said.

This would come about two years after HP's WebOS tablet debacle. In August of 2011, the company terminated its TouchPad only a month and a half after the device's introduction.

It also ended plans for a WebOS-based phone at that time.

HP currently offers the
Windows 8-based ElitePad 900 tablet and a Windows 8 hybrid tablet-laptop: the Envy x2. Both are based on Intel's power-efficient -- and relatively slow -- Atom processor.

And it already has one product based on a Google operating system. It's selling a Chromebook for $330.

HP declined to comment.

Remember the WebOS-based HP TouchPad? This time HP will adopt Android. The company already has a Windows 8 tablet.

(Credit:
Hewlett-Packard)

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Severe Weather More Likely Thanks to Climate Change

Jane J. Lee

BOSTON—Wildfires. Droughts. Super storms.

As opposed to representing the unfortunate severe weather headlines of the last year, scientists said Friday that climate change has increased the likelihood of such events moving forward.

And though the misery is shared from one U.S. coast to another, scientists speaking at the annual American Association for the Advancement of Science meeting in Boston said, the type of extreme event may vary significantly from region to region. (Related: "6 Ways Climate Change Will Affect You.")

Heat waves have become more frequent across the United States, with western regions setting records for the number of such events in the 2000s, said Donald Wuebbles, a geoscientist with the University of Illinois at Urbana-Champaign.

But the Midwest and Northeast have experienced a 45 percent and 74 percent increase, respectively, in the heaviest rainfalls those regions have seen since 1950.

The extreme drought that plagued Texas in 2011 has spread to New Mexico, Louisiana, Oklahoma, and northern Mexico, said John Nielsen-Gammon, Texas State's climatologist at Texas A&M University in College Station.

"The science is clear and convincing that climate change is happening and it's happening rapidly. There's no debate within the science community ... about the changes occurring in the Earth's climate and the fact that these changes are occurring in response to human activities," said Wuebbles.

In 2011 and 2012, major droughts, heat waves, severe storms, tornadoes, floods, hurricanes, and wildfires caused about $60 billion in damages each year, for a total of about $120 billion.

According to the National Oceanic and Atmospheric Administration Climactic Data Center, these were some of the costliest weather events in the country's history, said Wuebbles.

President Obama argued in his State of the Union address this week that the time is ripe to address climate change, saying he would skirt Congress to make such changes, if necessary.

His proposals included a system similar to the cap-and-trade proposal killed in Congress during his first term, new regulations for coal-burning power plants, and a promise to promote energy efficiency and R&D efforts into cleaner technologies. (Related: "Obama Pledges U.S. Action on Climate, With or Without Congress.")

The researchers said they are glad to see that addressing climate change is on the President's agenda. But they stressed that they wanted the public to have access to accurate, scientifically sound information, not just simplified talking points.

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Carnival Cruise Ship Hit With First Lawsuit

The first lawsuit against Carnival Cruise Lines has been filed and it is expected to be the beginning of a wave of lawsuits against the ship's owners.

Cassie Terry, 25, of Brazoria County, Texas, filed a lawsuit today in Miami federal court, calling the disabled Triumph cruise ship "a floating hell."

"Plaintiff was forced to endure unbearable and horrendous odors on the filthy and disabled vessel, and wade through human feces in order to reach food lines where the wait was counted in hours, only to receive rations of spoiled food," according to the lawsuit, obtained by ABCNews.com. "Plaintiff was forced to subsist for days in a floating toilet, a floating Petri dish, a floating hell."

Click Here for Photos of the Stranded Ship at Sea

The filing also said that during the "horrifying and excruciating tow back to the United States," the ship tilted several times "causing human waste to spill out of non-functioning toilets, flood across the vessel's floors and halls, and drip down the vessel's walls."

Terry's attorney Brent Allison told ABCNews.com that Terry knew she wanted to sue before she even got off the boat. When she was able to reach her husband, she told her husband and he contacted the attorneys.

Allison said Terry is thankful to be home with her husband, but is not feeling well and is going to a doctor.

Carnival's Triumph Passengers: 'We Were Homeless' Watch Video

Girl Disembarks Cruise Ship, Kisses the Ground Watch Video

Carnival Cruise Ship Passengers Line Up for Food Watch Video

"She's nauseated and actually has a fever," Allison said.

Terry is suing for breach of maritime contract, negligence, negligent misrepresentation and fraud as a result of the "unseaworthy, unsafe, unsanitary, and generally despicable conditions" on the crippled cruise ship.

"Plaintiff feared for her life and safety, under constant threat of contracting serious illness by the raw sewage filling the vessel, and suffering actual or some bodily injury," the lawsuit says.

Despite having their feet back on solid ground and making their way home, many passengers from the cruise ship are still fuming over their five days of squalor on the stricken ship and the cruise ship company is likely to be hit with a wave of lawsuits.

"I think people are going to file suits and rightly so," maritime trial attorney John Hickey told ABCNews.com. "I think, frankly, that the conduct of Carnival has been outrageous from the get-go."

Hickey, a Miami-based attorney, said his firm has already received "quite a few" inquiries from passengers who just got off the ship early this morning.

"What you have here is a) negligence on the part of Carnival and b) you have them, the passengers, being exposed to the risk of actual physical injury," Hickey said.

The attorney said that whether passengers can recover monetary compensation will depend on maritime law and the 15-pages of legal "gobbledygook," as Hickey described it, that passengers signed before boarding, but "nobody really agrees to."

One of the ticket conditions is that class action lawsuits are not allowed, but Hickey said there is a possibility that could be voided when all the conditions of the situation are taken into account.

One of the passengers already thinking about legal action is Tammy Hilley, a mother of two, who was on a girl's getaway with her two friends when a fire in the ship's engine room disabled the vessel's propulsion system and knocked out most of its power.

"I think that's a direction that our families will talk about, consider and see what's right for us," Hilley told "Good Morning America" when asked if she would be seeking legal action.

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Sand-grain-sized drum extends reach of quantum theory

The banging of a tiny drum heralds the intrusion of the weird world of quantum mechanics into our everyday experience. Though no bigger than a grain of sand, the drum is the largest object ever to have been caught obeying the uncertainty principle, a central idea in quantum theory.

As well as extending the observed reach of quantum theory, the finding could complicate the hunt for elusive gravitational waves : it suggests that the infinitesimal motion caused by these still-hypothetical ripples in spacetime could be overwhelmed by quantum effects.

The uncertainty principle says that you cannot simultaneously determine both a particle's exact position and momentum. For example, bouncing a photon off an electron will tell you where it is, but it will also change the electron's motion, creating fresh uncertainty in its speed.

This idea limits our ability to measure the properties of very small objects, such as electrons and atoms. The principle should also apply to everyday, macroscopic objects, but this has not been tested – for larger objects, the principle's effects tend to be swamped by other uncertainties in measurement, due to random noise, say.

Quantum drum

To extend the known reach of the uncertainty principle, Tom Purdy and colleagues of the University of Colorado, Boulder, created a drum by tightly stretching a 40-nanometre-thick sheet of silicon nitride over a square frame with sides of half a millimetre – about the width of a grain of sand. They placed the drum inside a vacuum chamber cooled to a few degrees above absolute zero, minimising any interference by random noise.

By continuously firing a stream of photons at the drum they were able to get increasingly precise measurements of the position of the skin at any moment. However, this also caused the skin to vibrate at an unknown speed. When they attempted to determine its momentum, the error in their measurement had increased – just as the uncertainty principle predicts.

"You don't usually have to think about quantum mechanics for objects you can hold in your hand," says Purdy.

That the uncertainty principle holds sway at such a large scale could affect the hunt for gravitational waves, which are predicted by Einstein's theory of general relativity but have never been detected.

Mitigation strategy

Gravitational wave detectors look for very slight changes in the distance between two test masses caused by passing spacetime ripples. Purdy says his team's experiment confirms long-held suspicions that quantum uncertainty could overwhelm these very small changes.

Now he and others can use the drum to explore more advanced measurement techniques to mitigate the effects. For example, uncertainty in an object's momentum could lead to future uncertainty in its position and there should be ways to minimise such knock-on effects. "You can't avoid the uncertainty principle, but you can in some clever ways make it [such that] increasing the momentum doesn't add back to the uncertainty in position at a later time," says Purdy.

His experiment is a neat demonstration of the breakdown of the traditional notion that the atomic world is quantum while the macroscopic world is classic, says Gerard Milburn of the University of Queensland in Brisbane, Australia, who was not involved in the work. Previous, attempts to blur the quantum-classical divide have involved entangling diamonds and demonstrating quantum superposition in a strip of metal.

Despite these feats, Milburn doesn't rule out the prospect of a breakdown on really large scales. "Of course maybe one day we will see quantum mechanics fail at some scale. Testing it to destruction is a good motivation for going down this path," he says.

Journal reference: Science, DOI: 10.1126/science.1231282

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Researchers collaborate on system to extend battery lifespan in devices

SINGAPORE: Researchers from Singapore and the US are collaborating to come up with a system that can extend the lifespan of batteries in devices such as laptops and smartphones.

The Institute of Microelectronics (IME) and Stanford University will work to advance innovations in nano-electromechanical systems (NEMS).

NEMS technology is known for its higher energy efficiency.

The system has the ability to stamp out leakage currents that occur during passive standby mode in electronic devices.

Leakage current is one of the leading sources of power consumption in digital systems, using traditional semiconductor switches.

By replacing these traditional switches with NEMS switches, the total power consumption of a digital block can be reduced by up to 10 times.

Dr Lee Jae Wung, the IME Scientist leading the project, said: "One of the challenges in building a reliable NEMS switch is in achieving Thin Film Encapsulation to protect the switch structure and the contact materials from degradation and oxidation by providing proper vacuum condition and/or filling inert gas inside the cavity. IME's capabilities in back end of line compatible materials and processes are expected to contribute strongly in this area."

"NEMS relay has proven to be an effective complement to conventional Si CMOS technology for reducing power consumption. The collaboration with IME will advance this device technology to a manufacturing process that is suitable for co-integration with Si CMOS in practical applications," said Professor Philip Wong, Willard R. and Inez Kerr Professor in the School of Engineering at Stanford University.

The Institute of Microelectronics (IME) is a research institute of the Science and Engineering Research Council of the Agency for Science, Technology and Research (A*STAR).

- CNA/ck

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Iceland works to block Internet porn

If Iceland's Interior minister gets enough support, his country could be the first in the West to ban all Internet pornography. Ogmundur Jonasson is working on new legal measures that could make access to online porn nearly impossible, according to the Daily Mail.

"We have to be able to discuss a ban on violent pornography, which we all agree has a very harmful effects on young people and can have a clear link to incidences of violent crime," Jonasson told the Daily Mail. He added that the move isn't about censorship but rather the safety of women who appear in porn and children who may be exposed to it.

Jonasson's proposals include blocking porn IP addresses and making it illegal to use Iceland-based credit cards on X-rated Web sites.

Iceland has long held an adversarial stance against pornography. According to the Daily Mail, the country has already made it illegal to print and distribute porn. Now, Jonasson seems to want to bring Iceland's laws up to the Internet age.

The country's move to prohibit all porn stems from a 2010 government study. The study found that the violent nature of pornographic photos and videos, which are widely available on the Internet, have increased the rate of sexual abuse and rape in the country. It also concluded that children who were exposed to violent pornography showed signs of trauma.

Several other countries have tried to block online porn. In July, Indonesia shut down 1 million porn sites, and in November, Egypt also attempted to censor online pornography by blocking Web sites.

Like Iceland, the U.K. has also worked to keep Internet porn away from children. Last year, the government suggested putting rules on how X-rated sites are accessed. These rules included content filters where ISP customers would receive, by default, a filtered version of the Internet. Customers who did not want restricted Internet access would have to "opt in" to get the Internet uncensored.

Iceland's plan to totally block Internet porn seems to take the U.K.'s idea one step further.

"There is a strong consensus building in Iceland. We have so many experts from educationalists to the police and those who work with children behind this, that this has become much broader than party politics," Jonasson's political adviser Halla Gunnarsdottir told the Daily Mail. "At the moment, we are looking at the best technical ways to achieve this. But surely if we can send a man to the moon, we must be able to tackle porn on the Internet."

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Why We Walk … and Run … And Walk Again to Get Where We're Going

You have to get to a bus stop to catch the once-an-hour express ... or to a restaurant to meet a friend ... or to a doctor's office. You've got maybe a half a mile to cover and you're worried you'll be late. You run, then you stop and walk, then run some more.

But wait. Wouldn't it be better to run the whole way?

Not necessarily.

A new study by an assistant professor of mechanical engineering at Ohio State University tests the theory that people subconsciously mix walking and running so they get where they need to. The idea is that "people move in a manner that minimizes energy consumption," said the professor, Manoj Srinivasan.

Srinivasan asked 36 subjects to cover 400 feet (122 meters), a bit more than the length of a football field. He gave them a time to arrive at the finish line and a stopwatch. If the deadline was supertight, they ran. If they had two minutes, they walked. And if the deadline was neither too short nor too far off, they toggled between walking and running.

The takeaway: Humans successfully make the walk-run adjustment as they go along, based on their sense of how far they have to go. "It's not like they decide beforehand," Srinivasan said. (Get tips, gear recommendations, and more in our Running Guide.)

The Best Technique for "the Twilight Zone"

"The mixture of walking and running is good when you have an intermediate amount of time," he explained. "I like to call it 'the Twilight Zone,' where you have neither infinite time nor do you have to be there now."

That ability to shift modes served ancient humans well. "It's basically an evolutionary argument," Srinivasan said. A prehistoric human seeking food would want to move in a way that conserves some energy so that if food is hard to find, the hunter won't run out of gas—and will still be able to rev it up to escape predators.

The study, published on January 30 in the Journal of the Royal Society Interface, doesn't answer that question of how we make such adjustments.

Runners: Take a Break if You Need It

The mix of walking and running is also something that nonelite marathoners are familiar with. Covering 26.2 miles might take less of a toll if the runner stops running from time to time, walks a bit, then resumes a jogging pace. "You use less energy overall and also give yourself a bit of a break," Srinivasan noted. (Watch: An elite marathoner on her passion for running.)

One take-home lesson is: Runners, don't push it all the time. A walk-run mix will minimize the energy you expend.

Lesson two: If you're a parent walking with your kid, and the kid lags behind, then runs to catch up, then lags again, the child isn't necessarily trying to annoy you. Rather, the child is perhaps exhibiting an innate ability to do the walk-run transition.

Potential lesson three: The knowledge that humans naturally move in a manner that minimizes energy consumption might be helpful in designing artificial limbs that feel more natural and will help the user reduce energy consumption.

The big question for Manoj Srinivasan: Now that he has his walk-run theory, does he consciously switch between running and walking when he's trying to get somewhere? "I must admit, no," he said. "When I want to get somewhere, I just let the body do its thing." But if he's in a rush, he'll make a mad dash.

"Talk to you tomorrow," he signed off in an email to National Geographic News. "Running to get to teaching now!"

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Dorner Confirmed Dead in Autopsy on Cabin Remains

Christopher Dorner, the ex-Los Angeles police officer who declared himself on a killing spree against his former law enforcement colleagues, is dead.

Authorities this evening confirmed that remains found after a fiery standoff at a California mountain cabin Tuesday were, in fact, Dorner's.

"The charred human remains located in the burned out cabin in Seven Oaks have been positively identified to be that of Christopher Dorner," the San Bernardino County Sheriff-Coroner's Office said in a written statement. "During the autopsy, positive identification was made through dental examination."

FULL COVERAGE: Christopher Dorner Manhunt

PHOTOS: Former LAPD Officer Suspected in Shootings

In a 6,000-word "manifesto," Dorner outlined his anger at the Los Angeles Police Department for firing him, and made threats against individuals he believed were responsible for ending his career with the police force five years ago. Dorner was fired after filing what the LAPD determined to be a false report accusing other cops of brutality.

Dorner is suspected of killing four people, including Monica Quan and her fiance, who were found shot to death Feb. 3. Quan was the daughter of former LAPD Capt. Randal Quan, who was mentioned as a target of Dorner's fury in the manifesto.

Christopher Dorner Hostages: 'I Thought We Were Dead' Watch Video

Christopher Dorner Hostages: 'He Just Wanted to Clear His Name' Watch Video

Christopher Dorner Believed Dead After Shootout With Police Watch Video

Dorner is also suspected in the shooting death of Riverside, Calif., Police Officer Michael Crain, whose funeral was Wednesday.

San Bernardino Sheriff's Deputy Jeremiah MacKay, 35, a 15-year veteran and the father of two children, was killed in Tuesday's shootout at the cabin.

A second San Bernardino County sheriff's officer had to undergo multiple surgeries after he was wounded in the cabin shootout, and other officers also were wounded in earlier alleged encounters with Dorner.

After Crain's death, police tracked Dorner to the Big Bear Lake area of Southern California, where his burning truck was found in the mountains late last week.

A couple with a cabin in the area were some of the last people to see Dorner before his final encounter with police. Their 911 call to police triggered a chase that concluded with the fiery standoff at the nearby cabin.

The couple, Karen and Jim Reynolds, said at a news conference Wednesday that their ordeal lasted a few minutes but seemed like hours.

The Reynolds believe Dorner, 33, was holed up starting Friday in their unoccupied cabin in Big Bear, Calif., only steps from where police had set up a command center.

"He said four or five times that he didn't have a problem with us, he just wanted to clear his name," Jim Reynolds said. "He said, 'I don't have a problem with you, so I'm not going to hurt you.'"

Dorner tied their arms and put pillowcases over their heads before fleeing in their purple Nissan, the couple said.

Before he fled, the couple said Dorner told them that he had been watching them before he took over their cabin. Dorner told the couple he could tell they were "hard working, good people."

"He had been watching us and saw me shoveling the snow Friday," Jim Reynolds said.

They say they may have left the cabin door unlocked and that could have been the reason Dorner was able to enter undetected.

Dorner remained "calm and meticulous" throughout the harrowing ordeal, the couple said.

The Reynolds walked into their cabin around noon Tuesday when they came face-to-face with Dorner. There was no question in their minds who he was -- the suspected cop killer at the center of one of the largest manhunts in recent memory.

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