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Bus services for intra-State migrants to begin on Monday; non-stop journeys envisaged

A multi-color light source is a significant tool for nonlinear optics experiments, pump–dump/repump–probe experiments and in other fields. Here, a novel method is proposed to create three-color pulses based on a high-gain harmonic-generation (HGHG) free-electron laser with a tilted electron bunch. In this method, the initial bunch tilt is created by transverse wakefields after the bunch passes through a corrugated structure with an off-axis orbit, and is further enlarged in a following drift section. Then the tilted bunch experiences the off-axis field of a quadrupole magnet to cool down the large transverse velocity induced before. After that, it enters an HGHG configuration adopting a transverse gradient undulator (TGU) as the radiator, where only three separated fractions of the tilted bunch will resonate at three adjacent harmonics of the seed wavelength and are enabled to emit three-color pulses simultaneously. In addition, the use of the natural transverse gradient of a normal planar undulator instead of the TGU radiator to emit three-color pulses is also studied in detail. Numerical simulations including the generation of the tilted bunch and the free-electron laser radiation confirm the validity and feasibility of this scheme both for the TGU radiator and the natural gradient in the extreme-ultraviolet waveband.

Wavefront sensing at X-ray free-electron lasers is important for quantitatively understanding the fundamental properties of the laser, for aligning X-ray instruments and for conducting scientific experimental analysis. A fractional Talbot wavefront sensor has been developed. This wavefront sensor enables measurements over a wide range of energies, as is common on X-ray instruments, with simplified mechanical requirements and is compatible with the high average power pulses expected in upcoming X-ray free-electron laser upgrades. Single-shot measurements were performed at 500 eV, 1000 eV and 1500 eV at the Linac Coherent Light Source. These measurements were applied to study both mirror alignment and the effects of undulator tapering schemes on source properties. The beamline focal plane position was tracked to an uncertainty of 0.12 mm, and the source location for various undulator tapering schemes to an uncertainty of 1 m, demonstrating excellent sensitivity. These findings pave the way to use the fractional Talbot wavefront sensor as a routine, robust and sensitive tool at X-ray free-electron lasers as well as other high-brightness X-ray sources.

The title compound {systematic name: N-[2-(5-meth­oxy-1H-indol-3-yl)eth­yl]-N-(prop-2-en-1-yl)prop-2-en-1-amine), C17H22N2O, has a single tryptamine mol­ecule in the asymmetric unit. The mol­ecules are linked by strong N—H⋯N hydrogen bonds into zigzag chains with graph-set notation C(7) along the [010] direction.

The solid-state structures of the naturally occurring psychoactive tryptamine norpsilocin {4-hy­droxy-N-methyl­tryptamine (4-HO-NMT); systematic name: 3-[2-(methyl­amino)­eth­yl]-1H-indol-4-ol}, C11H14N2O, and its fumarate salt (4-hy­droxy-N-methyl­tryptammonium fumarate; systematic name: bis­{[2-(4-hy­droxy-1H-indol-3-yl)eth­yl]methyl­aza­nium} but-2-enedioate), C11H15N2O+·0.5C4H2O42−, are reported. The freebase of 4-HO-NMT has a single mol­ecule in the asymmetric unit joined together by N—H⋯O and O—H⋯O hydrogen bonds in a two-dimensional network parallel to the (100) plane. The ethyl­amine arm of the tryptamine is modeled as a two-component disorder with a 0.895 (3) to 0.105 (3) occupancy ratio. The fumarate salt of 4-HO-NMT crystallizes with a tryptammonium cation and one half of a fumarate dianion in the asymmetric unit. The ions are joined together by N—H⋯O and O—H⋯O hydrogen bonds to form a three-dimensional framework, as well as π–π stacking between the six-membered rings of inversion-related indoles (symmetry operation: 2 − x, 1 − y, 2 – z).

Functional materials are of critical importance to electronic and smart devices. A deep understanding of the structure–property relationship is essential for designing new materials. In this work, instead of utilizing conventional atomic coordinates, a symmetry-mode approach is successfully used to conduct structure refinement of the neutron powder diffraction data of (1−x)AgNbO3–xLiTaO3 (0 ≤ x ≤ 0.09) ceramics. This provides rich structural information that not only clarifies the controversial symmetry assigned to pure AgNbO3 but also explains well the detailed structural evolution of (1−x)AgNbO3–xLiTaO3 (0 ≤ x ≤ 0.09) ceramics, and builds a comprehensive and straightforward relationship between structural distortion and electrical properties. It is concluded that there are four relatively large-amplitude major modes that dominate the distorted Pmc21 structure of pure AgNbO3, namely a Λ3 antiferroelectric mode, a T4+ a−a−c0 octahedral tilting mode, an H2 a0a0c+/a0a0c− octahedral tilting mode and a Γ4− ferroelectric mode. The H2 and Λ3 modes become progressively inactive with increasing x and their destabilization is the driving force behind the composition-driven phase transition between the Pmc21 and R3c phases. This structural variation is consistent with the trend observed in the measured temperature-dependent dielectric properties and polarization–electric field (P-E) hysteresis loops. The mode crystallography applied in this study provides a strategy for optimizing related properties by tuning the amplitudes of the corresponding modes in these novel AgNbO3-based (anti)ferroelectric materials.

Copper-containing nitrite reductases (CuNiRs) that convert NO2− to NO via a CuCAT–His–Cys–CuET proton-coupled redox system are of central importance in nitrogen-based energy metabolism. These metalloenzymes, like all redox enzymes, are very susceptible to radiation damage from the intense synchrotron-radiation X-rays that are used to obtain structures at high resolution. Understanding the chemistry that underpins the enzyme mechanisms in these systems requires resolutions of better than 2 Å. Here, for the first time, the damage-free structure of the resting state of one of the most studied CuNiRs was obtained by combining X-ray free-electron laser (XFEL) and neutron crystallography. This represents the first direct comparison of neutron and XFEL structural data for any protein. In addition, damage-free structures of the reduced and nitrite-bound forms have been obtained to high resolution from cryogenically maintained crystals by XFEL crystallography. It is demonstrated that AspCAT and HisCAT are deprotonated in the resting state of CuNiRs at pH values close to the optimum for activity. A bridging neutral water (D2O) is positioned with one deuteron directed towards AspCAT Oδ1 and one towards HisCAT N∊2. The catalytic T2Cu-ligated water (W1) can clearly be modelled as a neutral D2O molecule as opposed to D3O+ or OD−, which have previously been suggested as possible alternatives. The bridging water restricts the movement of the unprotonated AspCAT and is too distant to form a hydrogen bond to the O atom of the bound nitrite that interacts with AspCAT. Upon the binding of NO2− a proton is transferred from the bridging water to the Oδ2 atom of AspCAT, prompting electron transfer from T1Cu to T2Cu and reducing the catalytic redox centre. This triggers the transfer of a proton from AspCAT to the bound nitrite, enabling the reaction to proceed.

The electron linear accelerators driving modern X-ray free-electron lasers can emit intense, tunable, quasi-monochromatic terahertz (THz) transients with peak electric fields of V Å−1 and peak magnetic fields in excess of 10 T when a purpose-built, compact, superconducting THz undulator is implemented. New research avenues such as X-ray movies of THz-driven mode-selective chemistry come into reach by making dual use of the ultra-short GeV electron bunches, possible by a rather minor extension of the infrastructure.

Errors in the article by Opara, Martiel, Arnold, Braun, Stahlberg, Makita, David & Padeste [J. Appl. Cryst. (2017), 50, 909–918] are corrected.

"Physics for the 21st Century," a free, on-line course developed at the Harvard-Smithsonian Center for Astrophysics about current research in physics is now available.

The post Free, online course in physics offered by the Harvard-Smithsonian Center for Astrophysics appeared first on Smithsonian Insider.

Smithsonian scientists have confirmed that chytridiomycosis, a rapidly spreading amphibian disease, has reached a site near Panama’s Darien region. This was the last area in the entire mountainous neotropics to be free of the disease. This is troubling news for the Panama Amphibian Rescue and Conservation Project, a consortium of nine U.S. and Panamanian institutions that aims to rescue 20 species of frogs in imminent danger of extinction.

The post Deadly amphibian disease detected in the last disease-free region of Central America appeared first on Smithsonian Insider.

The Smithsonian Tropical Research Institute has released the first completely portable bilingual species identification guide for the shore fishes of the tropical Eastern Pacific as a free iPhone application.

The post First fish App from the Smithsonian free on iTunes. “The Smithsonian Guide to the Shore Fishes of the Tropical Eastern Pacific” appeared first on Smithsonian Insider.

New data just published in the journal Marine Mammal Science may help save the whales, or at least a good many of them. Using vertebrae […]

The post New study may help free whales from fishing rope entanglement appeared first on Smithsonian Insider.

For more than 60 years, researchers have tried to successfully cryopreserve (or freeze) the embryo of zebrafish, a species that is an important medical model […]

The post Gold nanotechnology and lasers used to successfully freeze fish embryos appeared first on Smithsonian Insider.

Isabella Guardamagna, Elisabetta Bassi, Monica Savio, Paola Perucca, Ornella Cazzalini, Ennio Prosperi, and Lucia A. Stivala

Assessing DNA repair is an important endpoint to study the DNA damage response for investigating the biochemical mechanisms of this process and the efficacy of chemotherapy, which often uses DNA damaging compounds. Numerous in vitro methods to biochemically characterize DNA repair mechanisms have been developed so far. However, they show some limitations mainly due to the lack of chromatin organization. Here we describe a functional cell-free system to study DNA repair synthesis in vitro, using G1-phase nuclei isolated from human cells treated with different genotoxic agents. Upon incubation in the correspondent damage-activated cytosolic extracts, containing biotin-16-dUTP, nuclei are able to initiate DNA repair synthesis. The use of specific DNA synthesis inhibitors markedly decreased biotinylated dUTP incorporation, indicating the specificity of the repair response. Exogenously added human recombinant PCNA protein, but not the sensors of UV-DNA damage DDB2 or DDB1, stimulated UVC induced dUTP incorporation. In contrast, a DDB2^PCNA- mutant protein, unable to associate with PCNA, interfered with DNA repair synthesis. Given its responsiveness to different type of DNA lesions, this system offers an additional tool to study DNA repair mechanisms.

The use of strongly bent crystals in spectrometers for pulses of a hard X-ray free-electron laser is explored theoretically. Diffraction is calculated in both dynamical and kinematical theories. It is shown that diffraction can be treated kinematically when the bending radius is small compared with the critical radius given by the ratio of the Bragg-case extinction length for the actual reflection to the Darwin width of this reflection. As a result, the spectral resolution is limited by the crystal thickness, rather than the extinction length, and can become better than the resolution of a planar dynamically diffracting crystal. As an example, it is demonstrated that spectra of the 12 keV pulses can be resolved in the 440 reflection from a 20 µm-thick diamond crystal bent to a radius of 10 cm.

What's possibly the most calming yet nerve-racking job in the world? Come behind the scenes of the Smithsonian's Freer Gallery of Art to find out!

The post Zen and the art of fine art conservation: Behind the scenes in the Freer Gallery’s art conservation lab appeared first on Smithsonian Insider.

A Projection Art Installation from the Smithsonian’s Freer Gallery of Art, “IlluminAsia Festival of Asian Art and Cultures” during the reopening celebration held in Oct. […]

The post Freer Gallery opening projection art installation appeared first on Smithsonian Insider.

Highlights of the year 2017 Freer Gallery of Art and Arthur M. Sackler Gallery

The post 2017 Freer|Sackler Year in Review appeared first on Smithsonian Insider.

Yesterday may have been a holiday on paper, but if you were navigating LA's major freeways, there was no sign people had the day off.

Steve Julian: Business analyst Mark Lacter, is this more evidence that Southern California traffic getting worse?

Mark Lacter: Steve, L.A. continues to be the most clogged-up city in the U.S. - according to something called the TomTom Traffic Index - with commuters caught up in delays, on average, 35 percent of the time.  Or, to put it another way, L.A. commuters are in congestion up to 40 minutes of each hour they're driving.  The worst time of the week to commute is Thursday night; that's when there's congestion more than 80 percent of the time.  Monday morning commutes are the lightest.

Julian: After L.A., where should you not live if congestion bugs you?

Lacter: The next worst cities in the U.S. are San Francisco, Honolulu, Seattle, and San Jose.  Now, the Census Bureau comes up with its own commuting surveys, and if you compare the most recent numbers with those back in 2000, you'll see that things aren't all that different.  Matter of fact, the percentage of commuters driving alone to work actually increased a little over the last decade to 72 percent, while the percentage of those carpooling has declined.

Julian: What about public transit?

Lacter: Well, the numbers are up slightly from 2000, but only to 7.3 percent of all commuters.  So, even assuming that the number inches up in the next couple of years when the Expo Line extends into Santa Monica, it's still a smallish piece of the pie.  And, since many of the other public transit projects being planned are decades away from being completed, those numbers might not change much.  One other thing, Steve: less than 1 percent of all L.A. commuters bike to work, which would throw cold water on the idea that biking in L.A. is becoming a popular way of getting to the office.

Julian: People just prefer commuting by car…

Lacter: It remains the most convenient way of getting around - despite the congestion.  New car sales are up 14 percent through the first nine months of the year in Southern California.  Add to that are generally affordable gas prices (they've been especially low in the last few weeks).  In other parts of the world, congestion is considered a good thing because it means that the economy is doing well.  Which explains that while L.A. is the most congested city in the U.S., it doesn't rank among the 10 around the world.  On that front, Moscow is tops, followed by Istanbul, and Rio de Janeiro.

Julian: What about driverless cars?

Lacter: Well, these vehicles hold the most promise for reducing accidents, lowering travel times, and improving fuel economy - and you don't have to give up your car.  Actually, a lot of the technology is already in place - that includes stuff like radar-based cruise control, and devices that keep you at a safe distance from the car in front of you.  The trick, of course, is taking these individual capabilities and integrating them into an entirely driverless car.  Several car companies say they could be ready to start selling by 2020, with Google saying that its car could be ready even sooner.

Julian: Is that realistic?

Lacter: Who knows?  But even if the dates can be met - and that's a big if, considering how complex these systems are - legislatures will have to determine, among other things, whether vehicles can be fully autonomous (meaning that you can curl up and take a nap while the computer is driving by itself).  Or, whether they will only be semi-autonomous, which would be like an airline crew using automatic pilot, but always prepared to take over the controls.

Julian: Is that a liability issue?

Lacter: Yes - if something does go wrong, who will get the blame?  The owner of the vehicle?  The carmaker?  The suppliers of the car companies?  These questions might take years to get resolved in the courts - and even then, it could be years before the percentage of these vehicles on the road is large enough to truly have an impact.  But, considering that most commuters aren't willing to give up their cars, this would seem to be the most exciting, most desirable idea.  One day.

Mark Lacter writes for Los Angeles Magazine and pens the business blog at LA Observed.com.

This content is from Southern California Public Radio. View the original story at SCPR.org.

Global money transfer service Azimo has announced waiving fees for transfers to Nigeria as the...

As of today all PDF versions of books published by the National Academies Press will be downloadable to anyone free of charge. This includes a current catalog of more than 4,000 books plus future reports produced by the Press.

A new report from the National Academies of Sciences, Engineering, and Medicine finds that there is no risk-free setting for giving birth, whether at home, in a birth center, or in a hospital.

This is a public service campaign suggesting you save water...and suggesting some other things too. ; Credit: SFPUC

Friday's news is going to make you wait for it...when it comes to an explanation for the picture above.

The Wall Street Journal takes on pricing and other big-think policies that various authors claim are worsening the drought.

• Those higher food prices Jed wrote about yesterday? Alyssia Finley, assistant editor of OpinionJournal.com, says they're the fault of environmentalists, and higher food prices will be the way the rest of the country will pay for California's "green sanctimony." (WSJ)
• Economist Edward Lazear argues that "government-dictated prices, coupled with restrictions on the transfer of water, have made a bad situation much worse." He takes aim at the state's limitations on water transfers (lifted, he doesn't note; but he argues that pricing distorts the need for transfers anyway). He argues that public agencies that protect environmental conditions with water should pay for the privilege:

Although there may be good reasons to ensure that some fish and wildlife be protected, we should not pretend that this protection is costless. Agencies that divert water for environmental purposes should be required to budget explicitly for the lost revenue associated with the decision to divert it for this purpose, rather than allowing it to be sold at the market price for urban or agricultural use. (WSJ)

...and he argues that farmers, who might have to pay more for water on a more-open market, should get extra money to help them transition to the free market.

• Cato loves Lazear's arguments, and offers one amendment. Chris Edwards wants the federal government to get out of the water business, and in California, to hand over the Central Valley Project to the state. (Cato)
• In other business news, it's going to be a mixed bag for boat businesses at California recreation areas this summer. They're nervous in Tahoe, but overall expect to benefit from Folsom Lake's bad year. (TradeOnly Today)
• CNN gets into the Firehawk, which is a U.S. Army Black Hawk helicopter with a giant water tank on it. L.A. County owns a few. They're going to be busy this summer, thanks to the drought. (CNN)
• And finally, in a move that reminds me of the time I wanted to name this blog "Hot, Wet, Climate Action," the San Francisco Public Utility Commission has a new, sexy (or is it sexxy?) campaign to conserve water, with words like "QUICKIE" and "DOING IT" popping out of copy alongside minimalist pictures of pieces of water plumbing. My favorite is "DIRTY HANDS" with its faucet shot to look like a piece of anatomy. (SFPUC)

VIDEO: Get paid for doing it nice!

How has your community been affected by the drought (besides getting more suggestive ads about jiggling the toilet handle)? Share your story with a photo on Twitter or Instagram. Tag it #mydrought. For more details on our photo project, click here.

This content is from Southern California Public Radio. View the original story at SCPR.org.

Perk Labs has formally launched new verticals and unveiled the...

I got the word this week from The Crest of Westwood that they'll be streaming coverage of the Golden Globes at The Crest on Sunday.

It's free and open to the public; doors open at 4:30 and the event starts at 5pm.

The Crest's Virginia Chavez writes, "We're encouraging formal attire, but it's not required for entrance."

But Off-Ramp says, "Phooey! Dress up. It's what classy people do." Like this stunning couple:

(Anne Knudsen/LA Public Library Herald-Examiner collection)

The caption of this 1985 photo reads, "David Hasselhoff in a burgundy-and-black striped tuxedo kept pace with wife Catherine Hickland's high fashion style: Ellene Warren's silk shoulder-beaded jacket, silk jacquard pants and matching evening bra. Hasselhoff and Hickland attended the Emmy Awards at the Pasadena Civic Auditorium.

There's such a thing as an "evening bra?" I don't think so.

The Crest - 1262 Westwood Blvd. LA, CA 90024 - (323) 553 - 3500

This content is from Southern California Public Radio. View the original story at SCPR.org.