DENVER (AP) — Scientists are working to pinpoint the source of a giant mass of methane hanging over the southwestern U.S., which a study found to be the country's largest concentration of the greenhouse gas.

The report that revealed the methane hot spot over the Four Corners region — where Colorado, New Mexico, Utah and Arizona meet — was released last year.

Now, scientists from the University of Colorado, the University of Michigan, the National Oceanic and Atmospheric Administration and NASA are conducting a monthlong study to figure out exactly where it came from.

The answer could help reduce methane emissions that contribute to global warming. Here are some key things to know:

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HOT SPOT

Last year's study by NASA and the University of Michigan was based on images from a European satellite captured between 2003 and 2009. They showed the methane hot spot as a red blip over the area, which is about half the size of Connecticut.

The study found the concentration of methane detected there would trap more heat in the atmosphere than all the carbon dioxide produced each year in Sweden.

Methane doesn't last as long in the atmosphere as carbon dioxide, but it's far more potent for capturing heat in the short term.

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POSSIBLE SOURCES

Methane occurs naturally and also is emitted by landfills and the agricultural and oil and natural gas industries.

One possible source of the hot spot is methane released from the region's coal deposits.

The releases can happen naturally, especially where coal seams reach the earth's surface. They also occur deliberately when energy companies extract methane — the primary component of natural gas — from coal beds.

The region is home to the San Juan Basin, North America's most productive area coal bed methane extraction area.

Methane also is released by coal mining and oil and gas drilling systems, and cattle produce large amounts of the gas. Scientists can pinpoint the kind of methane created by fossil fuels by looking for the presence of associated hydrocarbons.

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HEALTH EFFECTS

The methane emissions pose no direct safety or health risks for Four Corners residents, although the hot spot does factor into overall global warming.

Also, methane emitted from traditional oil and gas operations usually is accompanied by hydrocarbon emissions that can create ozone, a pollutant that leads to smog and is linked to asthma and respiratory illness.

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INVESTIGATING THE MYSTERY

For the next month, scientists based in Durango will fly in planes with a variety of instruments that can sense methane in the San Juan Basin. Crews in vans will follow up on their leads on the ground.

The European satellite that captured the hot spot is no longer in use, but Japan's GOSAT satellite plans to focus in on the Four Corners when it passes over the area.

It's possible methane levels over the Four Corners have changed since 2009, said Gabrielle Petron, a scientist at the University of Colorado's Cooperative Institute for Research in Environmental Sciences who is working on the latest study. Coal bed methane operations have declined since then, but oil production has increased.

TOSHIFUMI KITAMURA, AFP APR. 10, 2015, 5:38 AM

REUTERS/Kyodo Children looking at melon-headed whales beached on the shore of Hokota city, northeast of Tokyo, on Friday.

More than 130 melon-headed whales, a member of the dolphin family usually found in the deep ocean, beached in Japan on Friday, sparking frantic efforts by locals and coastguards to save them.

Rescuers were battling to stop the creatures' skin from drying out as they lay on a beach about 100 kilometers (60 miles) northeast of Tokyo, while some were being carried in slings back toward the ocean.

Television footage showed several animals from the large pod had been badly cut, with many having deep gashes on their skin.

An AFP journalist at the scene said that despite efforts to get the dolphins into the water, some were being pushed back onto the beach by the tide soon after they had been released.

Some of the creatures had died, he said, and were being buried.

"We see one or two whales washing ashore a year, but this may be the first time to find over 100 of them on a beach," a coastguard official told AFP.

The pod was stretched out along a roughly 10-kilometer-long stretch of beach in Hokota, Ibaraki, where they had been found by locals early Friday morning.

"They are alive. I feel sorry for them," a man told public broadcaster NHK, as others were seen ferrying buckets of seawater to the stranded animals and pouring it over them.

Several animals could be seen writhing in a futile effort to move themselves on the sand, though as the morning progressed they were clearly becoming weaker.

Melon-headed whales, also known as electra dolphins, are relatively common in Japanese waters and can grow to be 2 to 3 meters (6 to 9 feet) long.

In 2011, about 50 melon-headed whales beached themselves in a similar area.

Despite international opprobrium, Japan hunts minke and pilot whales off its own coast and has for many years also pursued the mammals in the Antarctic Ocean using a scientific exemption to the international moratorium on whaling.

Local residents trying to save the melon-headed whales stranded on the coast in Hokota.

It has never made any secret of the fact that meat from the animals is also consumed.

A UN court ruled last year, however, that its hunt was a commercial activity masquerading as research, and ordered it be halted.

Tokyo, which insists whaling is a tradition and labels environmental campaigners as "cultural imperialists," has vowed to restart a redesigned southern ocean whaling program, possibly later this year.

Japan also defies international opinion with the slaughter of hundreds of dolphins in a bay near the southern whaling town of Taiji.

The killing was brought to worldwide attention with the Oscar-winning documentary "The Cove."

JAZAN (Saudi Arabia) (AFP) - The Saudi border guard points past a crumbling, abandoned village towards a road barely visible against the hazy backdrop of Yemen's towering mountains.

"That is the Red Line," he says.

Beyond it lies Yemen and the threat from its Shiite militia who have already killed three Border Guard troopers since a Saudi-led coalition began air strikes last month to stop a rebel advance on Yemen's port city of Aden.

Hundreds of kilometres (miles) from the battle for the city, the Border Guard force -- supported by Saudi artillery and army troops -- have reinforced the kingdom's frontier along the Huthi's traditional north Yemen stronghold of Sadaa.

"We took control of all the high points," the officer says atop the three-storey observation tower on a sandy hill which even a four-wheel drive vehicle struggles to ascend.

The post, named "Tayash", was established one month ago. On the roof, two machine gunners aim their weapons out over the deserted brownish-green valley stretching for several kilometres towards Yemen's scrubby mountains.

Since a 2009 incursion by the Huthis, Saudi Arabia has relocated villagers to modern housing compounds further from the border in a bid to improve security.

All that remains in the valley are abandoned clusters of roofless buildings and a distant mosque now devoid of worshippers.

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Members of the Saudi border guard stationed at a look-out point on the Saudi-Yemeni border, in south …

So far, no shots have been fired in anger at this post, guards say.

"There are no Huthis" nearby, one says, a rifle slung over his shoulder as he stands on the edge of the hill above an armoured personnel carrier.

To make sure, other guards scan the terrain with binoculars.

A noisy electricity generator powers their wind-blown base, which includes ground-floor sleeping quarters, about 100 kilometres from Saudi Arabia's most southwestern city, Jazan.

- Heavy firepower -

Similar observation points and a communications tower can be seen on nearby hills.

Colonel Hasan Ageeli commands this sector of around 70 kilometres (40 miles) of frontier.

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A member of the Saudi border guard pictured at a look-out point on the Saudi-Yemeni border in southw …

He told visiting reporters he is confident there will be no repeat of 2009, when Huthis occupied two small Saudi border villages -- sending Saudi warplanes, artillery and special forces into action.

Ageeli, with a closely-cropped black beard, said the kingdom is far-better prepared to face an incursion, with upgraded equipment and new observation posts offering a full overview of the buffer zone.

His men are also in high spirits, he said.

"They want to defend their country and feel proud," Ageeli said.

The only Saudi casualties since a Riyadh-led coalition began air raids on Yemeni rebels two weeks ago have been the three border guards shot dead in separate incidents in the Asir region, adjacent to Jazan.

There have not been regular exchanges of fire even though some Huthi positions are only 100-150 metres from Saudi guards, Ageeli said.

Heavy firepower is close at hand if need be.

A few minutes drive from the Tayash post, AFP saw army artillery batteries and communication units, with about a dozen tanks and several armoured personnel carriers partially obscured behind a newly-erected white fence.

The front line is far enough away from Jazan city that most people there see no reason to worry.

"We are far from the border," one resident of the Red Sea city said. "People are not afraid."

"There is no problem," said another young man, wearing a traditional white thobe as strolled on the wide but near-deserted corniche.

But Abu Ibrahim, a taxi driver, isn't so relaxed despite his smile and warm demeanour.

The coalition has not so far sent ground troops into Yemen. It says its aircraft have been destroying rebel missiles and other targets, but Ibrahim fears the Huthis still a pose threat to his city, home to a naval base and other security facilities.

"If there is a ground operation we worry the rebels might respond and hit the city with missiles," he said. "But right now it's peaceful."

SAN DIEGO (AP) — A 16-year-old transgender girl who spoke on YouTube about being bullied at school in Southern California killed herself, a support group said, raising questions about what educators can and should do to support students who change gender identity.

Taylor Alesana was constantly picked on by peers before taking her life last week, the North County LGBTQ Resource Center said.

"With few adults to turn to, and with no support from her school, her life became too difficult," the group said. "Taylor was a beautiful and courageous girl, and all she wanted was acceptance."

Alesana attended meetings at the center and was very supportive of others, said Max Disposti, the group's executive director. She posted a series of online videos that included makeup tutorials and accounts of her struggles.

In her first video posted in October, she said bullying began at a San Diego-area middle school when she disclosed that she was bisexual.

"I fear for anyone that's even just a little bit different. They know what bullying is like," she said.

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In this still image from a YouTube video posted on Feb. 28, 2015, Taylor Alesana gives tips on makeu …

Alesana said her family recently moved to Fallbrook — a community of about 30,000 people next to Camp Pendleton Marine Corps base, 70 miles north of San Diego — and that she was "living my life as a girl now," wearing female clothing on weekends and during summer. She eventually found friends at Fallbrook High School but encountered rejection first.

"I made a couple (friends), went from group to group. The group would usually kick me out after they realized, 'Oh, you're different. We can't have you hanging out with us,'" she said.

Alesana had a strong relationship with her school counselor but administrators "didn't take the necessary steps," Disposti said. They never contacted his organization, even after a Thursday night vigil at his Oceanside office that was attended by Alesana's family and about 200 others, he said.

Fallbrook Union High School District Superintendent Hugo Pedroza said in a statement that a student died tragically on April 2. "It is never easy when something like this happens, but we are working to move forward together and stronger than before," he said.

Experts said schools must train staff to be alert to bullying and instill in students that it is unacceptable, but they also need to acknowledge any of their own biases.

"The fears that students have of transgender youth actually stem from adults," said Dorothy Espelage, professor of educational psychology at University of Illinois, Urbana-Champaign. "If you're not going change the attitude of the adults, you're not going to change the attitudes of the kids."

James Garbarino, professor of humanistic psychology at Loyola University in Chicago, said transgender students are in a similar position as gay and lesbian students 10 or 20 years ago. Homophobic bullying remains a serious problem, but it has declined to the point that gays and lesbians are elected prom kings and queens.

"What really drives this — whether gender, race, class — is how the adult society views these issues," he said.

Alesana is the second transgender teen who sought services at the North County LGBTQ Resource Center to die by suicide since March, Disposti said. A boy who took his life last month had a supportive environment at home and school, but he struggled with other issues, including his mother's death.

Alesana was unusually vocal about the challenges of being a transgender teen. An effort to reach her family through Disposti was unsuccessful.

"She was very outspoken and had incredibly positive energy," Disposti said. "She was helping others as she was struggling."

SAN BERNARDINO, Calif. (AP) — Ten sheriff's deputies in Southern California have been put on leave after several of them were shown on video kicking and punching a man following a 2½-hour chase involving a stolen horse.

San Bernardino County Sheriff John McMahon said Friday that the video "disturbed and troubled" him and appeared to show an excessive use of force.

McMahon announced the action after 30-year-old Francis Pusok was arrested Thursday by deputies in a violent encounter filmed by a KNBC-TV helicopter (http://bit.ly/1H8UC3D). Pusok fled by car and then on the horse, traveling several miles while deputies chased him on foot after trying to serve a search warrant in an identity-theft investigation.

The video shows Pusok, dressed in bright red clothing, falling from the horse as a deputy ran up and fired a Taser. McMahon said the Taser was believed to be ineffective because of Pusok's loose clothing.

As pursuing deputies reached him, Pusok was face down with his arms and legs outstretched and hands behind his back. One deputy kicked him in the head or shoulder area and punched him, and another kicked him in the crotch. Other deputies arrived moments later.

McMahon said internal and criminal investigations are under way. The FBI announced Friday it was starting a civil rights investigation.

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This undated booking photo provided by the San Bernardino County Sheriff's Department shows Fran …

"I'm asking for some patience while we complete a thorough and fair investigation," McMahon said. "I am disturbed and troubled by what I see in the video. It does not appear to be in line with our policies and procedures.

"I assure you, if there is criminal doing on the part of any of our deputy sheriffs or any policy violations, we will take action."

McMahon said the department received multiple threats after the video was aired. He said names of the deputies, including a sergeant and a detective, won't be released until the threats are checked out. The deputies were place on paid administrative leave.

Attorneys for Pusok told KNBC-TV Friday as they left the jail that their client has a badly swollen eye, marks from the beating over his face and body, and is in pain.

"He remembers being beat, and he remembers that he wasn't resisting, that he laid still, he complied immediately. He says that he didn't even move a muscle because he didn't want to be continuously beat, yet it still happened," attorney Sharon Brunner said.

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In this frame from video provided by KNBC-TV, officers surround a man Thursday, April 9, 2015, near …

After the beating, a deputy whispered in his ear: "This isn't over,'" attorney Jim Terrell said.

"And that's why he's scared to death for himself and his family right now," Terrell said.

The beating is the latest in a string of recent videotaped incidents involving police officers using extreme force on suspects, including the shooting death of an unarmed man as he ran from a police officer last weekend in North Charleston, South Carolina.

Ken Cooper, a New York-based use of force expert who trains police, said it appears the San Bernardino deputies allowed their emotions and adrenaline to get the best of them.

"When chasing a fleeing suspect, in high stress, you have to control that," he said. "The justification for using force is to gain compliance from the suspect, and the suspect seems to be complying. So what this looks like is those blows are not justified, they're not necessary and they're not professional."

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In this frame from video provided by KNBC-TV, officers near a man Thursday, April 9, 2015, near Appl …

Cooper said the officers should be disciplined, retrained to deal with stress, and the video should be used for training.

Pusok has a slew of vehicle code violations and pleaded no contest to several criminal charges, including multiple instances of resisting arrest, attempted robbery, animal cruelty and fighting or offensive words, according to San Bernardino County Superior Court records.

McMahon said deputies had previously been called to a home where Pusok allegedly made threats to kill a deputy and fatally shot a family puppy in front of his family members. "We were very familiar with his aggressive nature," McMahon said.

Pusok is being held on suspicion of felony evading, theft of a horse and possession of stolen property.

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Taxin reported from San Bernardino.

Abdollah can be reached at http://www.twitter.com/latams.

10 deputies disciplined after video surfaces

San Bernardino County Sheriff John McMahon says seeing his officers beat a horse theft suspect "troubled" him.
'We will take action'