California Sen. Kamala Harris (left) and Susan Rice, national security adviser under President Barack Obama Getty Images
Joe Biden’s veep list has reportedly narrowed to two candidates: Sen. Kamala Harris and Susan Rice.
According to an Axios report published Wednesday, the Democratic nominee, 77, is holed up in his Delaware home, where his campaign is in the final stages of vetting a handful of potential running mates.
But people close to Biden believe his search has narrowed to either Kamala Harris, the Democrat senator from California, or Susan Rice, President Barack Obama’s national security adviser, and they would be “surprised if he picks anyone else,” the report said.
A third contender is California Rep. Karen Bass, but her stock appears to have fallen in recent weeks after years-old comments of her praising Scientology and Cuban dictator Fidel Castro surfaced.
Biden previously said he would announce his running mate on Aug. 1, but is now not expected to name his veep until at least Aug. 10.
The search and rescue operation for eight U.S. servicemen who went missing last week after their landing craft sank in hundreds of feet of water off San Clemente Island during a training exercise has ended, officials announced early Sunday.
The seven Marines and one sailor who are missing are presumed dead, officials said.
“It is with a heavy heart, that I decided to conclude the search and rescue effort,” Col. Christopher Bronzi, commanding officer of the 15th Marine Expeditionary Unit, said in a statement. “The steadfast dedication of the Marines, Sailors and Coast Guardsmen to the persistent rescue effort was tremendous.”
With the assistance of helicopters, ships and boats, more than 1,000 square nautical miles were searched but it was determined that there was little probability of successful rescue given the circumstances of the incident, officials said. The 26-ton amphibious assault vehicle was beyond the reach of divers.
The incident occurred when the vehicle carrying 15 Marines and one Navy sailor began taking on water about 5:45 p.m. Thursday, according to the Marine Corps.
One Marine was taken to Scripps Memorial Hospital La Jolla and later died. Two others were injured and remain hospitalized but are no longer in intensive care.
Five other service members were rescued.
Efforts will now turn to finding and recovering the missing servicemen, officials said. Their names have not yet been released.
“Our thoughts and prayers have been, and will continue to be with our Marines’ and Sailor’s families, during this difficult time,” Bronzi said.
Since the 1980s, researchers have been running experiments in search of particles that make up dark matter, an invisible substance that permeates our galaxy and universe. Coined dark matter because it gives off no light, this substance, which constitutes more than 80 percent of matter in our universe, has been shown repeatedly to influence ordinary matter through its gravity. Scientists know it is out there but do not know what it is.
So researchers at Caltech, led by Kathryn Zurek, a professor of theoretical physics, have gone back to the drawing board to think of new ideas. They have been looking into the possibility that dark matter is made up of “hidden sector” particles, which are lighter than particles proposed previously, and could, in theory, be found using small, underground table-top devices. In contrast, scientists are searching for heavier dark matter candidates called WIMPs (weakly interacting massive particles) using large-scale experiments such as XENON, which is installed underground in a 70,000-gallon tank of water in Italy.
“Dark matter is always flowing through us, even in this room” says Zurek, who first proposed hidden sector particles over a decade ago. “As we move around the center of the galaxy, this steady wind of dark matter mostly goes unnoticed. But we can still take advantage of that source of dark matter, and design new ways to look for rare interactions between the dark matter wind and the detector.”
In a new paper accepted for publication in the journal Physical Review Letters, the physicists outline how the lighter-weight dark matter particles could be detected via a type of quasiparticle known as a magnon. A quasiparticle is an emergent phenomenon that occurs when a solid behaves as if it contains weakly interacting particles. Magnons are a type of quasiparticle in which electron spins—which act like little magnets—are collectivity excited. In the researchers’ idea for a table-top experiment, a magnetic crystalized material would be used to look for signs of excited magnons generated by dark matter.
“If the dark matter particles are lighter than the proton, it becomes very difficult to detect their signal by conventional means,” says study author Zhengkang (Kevin) Zhang, a postdoctoral scholar at Caltech. “But, according to many well-motivated models, especially those involving hidden sectors, the dark matter particles can couple to the spins of the electrons, such that once they strike the material, they will induce spin excitations, or magnons. If we reduce the background noise by cooling the equipment and moving it underground, we could hope to detect magnons generated solely by dark matter and not ordinary matter.”
Such an experiment is only theoretical at this point but may eventually take place using small devices housed underground, likely in a mine, where outside influences from other particles, such as those in cosmic rays, can be minimized.
One telltale sign of a dark matter detection in the table-top experiments would be changes to the signal that depend on the time of day. This is due to the fact that the magnetic crystals that would be used to detect the dark matter can be anisotropic, meaning that the atoms are naturally arranged in such a way that they tend to interact with the dark matter more strongly when the dark matter comes in from certain directions.
“As Earth moves through the galactic dark matter halo, it feels the dark matter wind blowing from the direction into which the planet is moving. A detector fixed at a certain location on Earth rotates with the planet, so the dark matter wind hits it from different directions at different times of the day, say, sometimes from above, sometimes from the side,” says Zhang.
“During the day, for example, you may have a higher detection rate when the dark matter comes from above than from the side. If you saw that, it would be pretty spectacular and a very strong indication that you were seeing dark matter.”
The researchers have other ideas about how dark matter may reveal itself, in addition to through magnons. They have proposed that the lighter dark matter particles could be detected via photons as well as with another type of quasiparticle called a phonon, which is caused by vibrations in a crystal lattice. Preliminary experiments based on photons and phonons are underway at UC Berkeley, where the team was based prior to Zurek joining the Caltech faculty in 2019. The researchers say that the use of these multiple strategies to look for dark matter is crucial because they complement each other and would help confirm each other’s results.
“We’re looking into new ways to look for dark matter because, given how little we know about dark matter, it’s worth considering all the possibilities,” says Zhang.
New ideas in the search for dark matter (2020, June 16)
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ort Hood officials and Special Agents from the U.S. Army Criminal Investigation Command are asking for the public’s assistance in locating Pfc. Vanessa Guillen, a 20-year-old Soldier stationed at Fort Hood, Texas. (Fort Hood Press Center)
A “Be on the Lookout” (BOLO) notice was issued by Fort Hood Military Police notifying surrounding law enforcement. An “extensive search” is underway by military members, as well as civilian and military police, the press release said.
Fort Hood officials and Special Agents from the U.S. Army Criminal Investigation Command are also asking for the public’s assistance in their search.
Her sister, Mayra Guillen, shared a Facebook post on Friday, writing: “My sister… last seen two days ago. Phone last tracked at Belton, Texas. No contact with boyfriend, close friends or family. Belongings and CAR are at base too back in fort hood. Something is not right please help me find her. Houston Austin Fr hood/ Killeen areas.”
The soldier’s boyfriend, Juan Cruz, also posted a message to Twitter.
“Please help me find my girlfriend her name is Vanessa Guillen,” he tweeted Friday. “Height 5’3. She has 3 tattoos on her left arm. Please anything helps.”
Fort Hood is a U.S. military post located in Killeen, Texas. It covers roughly 340 square miles of Coryell and Bell counties in central Texas between Waco and Austin and is home to III Corps and The First Cavalry Division, as well as many tenant units, according to Military.com