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Students aged 12 to 15 steered bus to safety and called for help after driver lost consciousness from asthma attack
Middle school students in Mississippi acted quickly to halt their school bus from crashing after their driver passed out while on a highway, prompting the operator to declare: “They saved my life.”
The bus in question had just left the Hancock middle school in the Mississippi community of Kiln on Wednesday when the driver, Leah Taylor, suffered an asthma attack and lost consciousness.
Continue reading...When Unai Emery declared the “Premier League is the priority” despite a looming Europa League semi-final, he could not have envisaged the lifeless display his Aston Villa team would produce at Craven Cottage.
Perhaps his players disagree with their manager’s preference for domestic affairs, or maybe the London spring sunshine proved too much of a distraction from footballing matters. Either way, Villa departed Craven Cottage on Saturday lunchtime with an emptiness fully deserving of their minimal endeavours, having managed just one shot on target all match.
Continue reading...Dnipro bore the brunt of the attacks but Odesa and Kharkiv were also targeted in largest onslaught for several days
Russian drone and missile strikes across Ukraine killed at least seven people overnight, including five in the city of Dnipro, Ukrainian local authorities have said.
Reports say that at least 34 people have been injured in the strikes, which lasted “practically all night”, according to the Dnipropetrovsk regional head, Oleksandr Hanzha. The bodies of four people were found in the ruins of a house destroyed in the attacks, and workers continued to search for bodies on Saturday morning.
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Physicists have proposed a new kind of atomic clock based on a revived superradiant laser concept that could produce an extraordinarily stable signal with a linewidth around 100 microhertz, potentially the narrowest ever for an optical laser. "The implications of this result could stretch well beyond timekeeping," reports Phys.org. "A laser immune to environmental frequency shifts would be a powerful tool in optical interferometry -- using interference patterns in light to make ultra-precise measurements." From the report: In a conventional laser, a mirrored cavity bounces light back and forth between atoms, building up a bright, coherent beam. A superradiant laser works differently: rather than relying on the cavity to maintain coherence, the atoms themselves act as single coordinated emitters, collectively synchronizing their light emission. Following early theoretical ideas emerged in the 1990s, the concept didn't gain concrete traction until 2008, when researchers at the University of Colorado proposed that superradiant lasers could serve as a new kind of atomic clock.
Atomic clocks work by using laser light to probe a very precise transition in an atom, causing electrons to transition between energy levels at an extraordinarily stable frequency. Because a superradiant laser stores its coherence in the atoms rather than the cavity, its output frequency is far less vulnerable to environmental disturbances like vibrations or temperature fluctuations. Yet although this concept was first demonstrated experimentally in 2012 in a pulsed regime, the influence of heating has so far held superradiant lasers back from their full potential. To keep the laser running continuously as an atomic clock requires, atoms must be constantly replenished with energy. Doing this atom-by-atom delivers random kicks that heat the atomic sample and disrupt the lasing process, confining it to brief pulses rather than a steady beam.
In their study, Reilly's team considered whether a modification to earlier theoretical concepts could make a continuous laser suitable for an atomic clock. In almost all previous studies, atoms were treated as simple two-level systems: an electron sitting in a ground state, occasionally jumping up to an excited state and back again. The team proposed that the heating problem could be solved by adding one extra ground state to the picture. In a two-level system, if both the pumping (re-energizing) and decay processes happen collectively through the cavity, the mathematics constrains the system in a way that prevents stable, continuous lasing. But with three levels available, pumping and decay can operate on entirely separate transitions, breaking that constraint and allowing the collective approach to work. The findings have been published in the journal Physical Review Letters.
Atomic clocks work by using laser light to probe a very precise transition in an atom, causing electrons to transition between energy levels at an extraordinarily stable frequency. Because a superradiant laser stores its coherence in the atoms rather than the cavity, its output frequency is far less vulnerable to environmental disturbances like vibrations or temperature fluctuations. Yet although this concept was first demonstrated experimentally in 2012 in a pulsed regime, the influence of heating has so far held superradiant lasers back from their full potential. To keep the laser running continuously as an atomic clock requires, atoms must be constantly replenished with energy. Doing this atom-by-atom delivers random kicks that heat the atomic sample and disrupt the lasing process, confining it to brief pulses rather than a steady beam.
In their study, Reilly's team considered whether a modification to earlier theoretical concepts could make a continuous laser suitable for an atomic clock. In almost all previous studies, atoms were treated as simple two-level systems: an electron sitting in a ground state, occasionally jumping up to an excited state and back again. The team proposed that the heating problem could be solved by adding one extra ground state to the picture. In a two-level system, if both the pumping (re-energizing) and decay processes happen collectively through the cavity, the mathematics constrains the system in a way that prevents stable, continuous lasing. But with three levels available, pumping and decay can operate on entirely separate transitions, breaking that constraint and allowing the collective approach to work. The findings have been published in the journal Physical Review Letters.
Read more of this story at Slashdot.
Bij de oprit van de A20 in Schiedam is zaterdagmiddag een auto uit de bocht gevlogen. De wagen kwam uiteindelijk onder de geluidswal naast de snelweg tot stilstand. De bestuurder kwam er zonder verwondingen vanaf.
Door het ontbreken van Jakub Moder, heeft hoofdtrainer Robin van Persie gekozen voor Kraaijeveld op het middenveld. Dat betekent dat Tobias van den Elshout nog altijd de linksbuiten van Feyenoord is. Verder keren achterin Gernot Trauner en Jordan Bos terug.
Een auto is zaterdagmiddag aan de Heiweg in Oud-Alblas in de sloot beland. Dat gebeurde tijdens het evenement Kids and Cars. In de Chevrolet Corvette zaten een man en een jongen, die beiden ongedeerd zijn gebleven.
Four people were killed and 27 wounded in a single strike on an apartment block in Dnipro. Another strike nearly killed a local official.