Heathrow again calls for testing regime as passenger numbers collapse | News

first_img– Advertisement – OlderNew research further undermines UK quarantine scheme NewerSteenbergen appointed chief financial officer at Lufthansa Heathrow chief executive, John Holland-Kaye, said: “Aviation is the lifeblood of the UK’s economy, critical for exports of goods and services and imports of vaccines, as well as inbound tourism, students and foreign direct investment. “Lack of government action is weakening our sector, making it harder for us to support the eventual economic recovery and help deliver the prime minister’s vision of a global Britain.”Heathrow argued the lack of a testing regime has left British airports unable to compete with EU rivals.- Advertisement – Passenger figures at Heathrow were down 82 per cent in October when compared to last year, as the Covid-19 pandemic continue to take a toll on global aviation. The airport also warned data for November was likely to be even worse, as England enters a four-week lockdown. – Advertisement – Long-haul and critical markets for trade suffered the worst declines, Heathrow said.This was due to the “debilitating quarantine requirements” put in place by the UK government. Overall cargo volumes were down 23 per cent compared to last year. – Advertisement – At the same time, the refusal to offer English and Welsh airports business rates relief runs the risk of worsening an already challenging situation and the plans to end VAT-free shopping threatens to kick our industry when its down, a statement added.The figures come as new research suggests the quarantine regime may be less effective than previously thought.last_img read more

Dubrovnik attracts guests with various discounts and benefits

first_imgAccording to the eVisitor tourist check-in and check-out system, there were 12 overnight stays in Dubrovnik last weekend, from 15 to 4 June, and on 253 June, 13 tourists stayed in Dubrovnik, mostly from Croatia and Germany. The 10st Dubrovnik Summer Festival opens on July 71 A special promotional campaign of the City of Dubrovnik and the Tourist Board of the City of Dubrovnik began on June 15, which includes numerous discounts and benefits for all visitors to the city of Dubrovnik, and lasts until the end of June. With a big discount for the city walls and Lokrum Reserve, many hotels, private renters, travel agencies and restaurants offer their services at reduced prices and the City of Dubrovnik for one purchased, offers one free week Dubrovnik Card.   Free entrance for all visitors is offered by the Trsteno Arboretum, Lazareti, the Homeland War Museum and the Dubrovnik Museums (Cultural and Historical Museum in the Rector’s Palace, Maritime Museum in the Fortress of St. John, Ethnographic Museum in the Rupa granary, exhibitions of the Archaeological Museum in the Revelin Fortress), Dom Marina Držić and the Dubrovnik Art Gallery.  Also, Dubrovnik museums have new opening hours and the institutions will be open from 10:00 to 18:00 from Tuesday to Sunday. This year’s 71st Dubrovnik Summer Festival will be held from July 10 to August 25, as announced, but in a reduced format due to the current epidemiological COVID-19 measures in Croatia and the world and the financial consequences of the pandemic. The festival audience of all generations expects almost fifty drama, music, dance, folklore and other performances at more than ten stage and ambient locations in the city of Dubrovnik, according to a new program proposal approved today by the Dubrovnik Summer Festival.  Photo: Dubrovnik Tourist Board Currently, 14 hotels and a little more than fifty restaurants have been opened in the city, and yesterday, with the landing of the first flight of Air Baltic, with 96 passengers on a flight from Riga, international air traffic to Dubrovnik was re-established. See a list of all the benefits HERE During this period, 2070 overnight stays were realized in hotel accommodation, 1426 in private accommodation, while a smaller number of overnight stays were realized in other forms of accommodation, reports the Dubrovnik Tourist Board. last_img read more


first_imgNeil Gallagher could be in action for LYIT tomorrow in their All-Ireland semi-final with St Pat’s.Donegal star Neil Gallagher could line out for the LYIT GAA team for their All-Ireland semi-final against St Pat’s tomorrow evening.LYIT manager Eamon O’Boyle may be able to call on the services of Gallagher who is back studying part-time at the college.Gallagher works for the Donegal County Council – but the influential midfielder has returned to the LYIT to study part-time. If he does lineout his presence would be a massive boost for O’Boyle’s side in their quest to reach the All-Ireland final.LYIT have a strong squad to choose from and have a number of Donegal U21 players in their squad to face St Pat’s.Jack O’Brien, Hugh Boyle, Willie Gillespie, Callum Gallagher (captain) Conal O’Boyle and the McDaid brother will be crucial for O’Boyle’s side if they’re to beat a highly fancied St Pat’s side.St Pat’s will compete in the prestigious Sigerson Cup competition and will be a formidable force. Donegal star Hugh McFadden is expected to lineout for the Dublin based teaching college.The game will be played at the Monaghan Centre of Excellence tomorrow at 5pm.LYIT FACE ST PAT’S IN ALL-IRELAND SEMI-FINAL IN MONAGHAN was last modified: November 26th, 2015 by Mark ForkerShare this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)Click to share on Telegram (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to share on Skype (Opens in new window)Click to print (Opens in new window) Tags:newsSportlast_img read more

Humboldt B52s look ahead after dropping first series of the 2016 season

first_imgEureka >> Summer baseball is officially in full affect for the semi-pro Humboldt B-52s after winning game one and losing games two and three against the visiting Novato Knicks in a three-game series to open the season. “Obviously it was good to get a win for the first game,” said B-52s board member and pitcher Brian Meyer. “We had a couple of heart-breaking losses for Saturday and Sunday, but overall our team seems to be clicking well and I have a good feeling for how the season is going to …last_img read more

Solar in the Land Down Under

first_imgSimilar issues confront the AussiesAustralian consumers and utilities seem to be facing many of the same challenges as their counterparts in the U.S. As prices for PV modules and battery storage fall, the systems grow ever more attractive for homeowners, putting more pressure on utilities to adapt their business models in response.“Storage technologies as well as PV will be able to provide costumers with electricity at a cheaper cost than the grid,” Bloomberg’s Kobad Bhavnagri says. “And as storage gets cheaper even larger amounts of storage will be able to supply consumers at a cheaper cost to the grid. On economic fundamentals this technology is unstoppable.”Bhavnagri and others believe 50% of all electricity will be supplied by sources “behind the meter” by 2040, Parkinson writes, but he sees a continuing role for the grid.“We will still need the grid for different purposes,” Bhavnagri writes, but inevitable changes in the way utilities operate will almost certainly mean a write-down in their value.“The business model of the networks has to change,” Bhavnagri told Bloomberg. “They have got to sell services instead of kilowatt-hours. Much of what they built is redundant, resulting in excess capacity, and networks are overcharging and not delivering a commodity or service that is valuable to consumers.”That sentiment is shared by many renewable energy advocates in the U.S. Utilities here have responded to pressure from the growth of residential solar in a variety of ways. A number of them have sought surcharges on solar customers to offset lower sales, but the issue is handled differently from state to state. The U.S. isn’t the only place where consumers are closely watching the solar panel market and wondering when the cost of electricity derived from photovoltaic (PV) panels on their rooftops will be the same as or lower than what they’d pay for power from a utility.In Australia, a report from Bloomberg New Energy Finance says that consumers already can install solar panels and battery storage to provide electricity for less than grid rates, and that the adoption of these twin technologies probably is “unstoppable.”The prediction was posted at One Step Off the Grid, a new spinoff website developed by RenewEconomy to cover the consumer side of the energy market there.In a post July 21, Giles Parkinson wrote that even if retail electricity prices remained flat, “rooftop solar PV can already provide power to consumers in homes at well below the price of [grid-supplied] electricity.”Bloomberg reports the price of PV electricity, with no battery storage, is lower than retail electricity, and well below the cost of grid power when the systems have batteries of either 1 kW or 3 kW. Prices appear about the same now when a 5 kW battery is included in the system, but all of those PV-plus-battery options are well below retail rates in projections going out to 2030.last_img read more

Insulating a Flat Roof

first_imgTom Jordan is a painting contractor in northern New Jersey who’s at his wit’s end as he tries to figure out a remodeling job at his own home. It seems simple enough. Jordan is turning a three-season room on his 1930s house into a fully conditioned space. The room measures 12 feet by 16 feet and has an 8-foot ceiling. The flat roof overhead is framed in full-depth 2x6s, finished with what Jordan believes is roll roofing (a type of asphalt roofing). “My issue is how to correctly insulate the ceiling,” he writes in a Q&A post. “I’ve spent what seems like hundreds of hours online and had a few insulation contractors look at the room, and I can’t believe the inconsistencies that exist on this subject.”RELATED ARTICLESCan Unvented Roof Assemblies Be Insulated With Fiberglass?Insulating Low-Slope Residential RoofsFlash-and-Batt InsulationSite-Built Ventilation Baffles for RoofsCut-and-Cobble Insulation In Climate Zone 5, the prescriptive table of the International Residential Code requires at least R-49 of ceiling insulation. With 2×6 rafters, that’s a tall order, and Jordan adds a couple of major caveats. “The roof is only four years old, so removing it is not an option,” he says, ruling out a layer of exterior rigid foam. “The room does not have any venting, nor is it possible to vent … Before anyone suggests closed-cell spray foam, I’m ruling that out. I have no confidence in the ‘healthiness’ of the product. It might be a great product, but I don’t want it in my house.” Those are the ground rules for this Q&A Spotlight. You need exterior insulation Convenient or not, Jordan will need exterior insulation over the roof sheathing in order to meet code minimums, says Ryan Lewis, advice that is seconded by GBA editor Martin Holladay. And it will be important to maintain the correct ratio of interior to exterior insulation. “You need sufficient exterior insulation, typically rigid foam — but I guess you could use other stuff, too,” Lewis writes. “In Zone 4A you need R-15. If you are in Zone 5 you need at least R-20.” In order to meet the R-49 requirement, Jordan will need the balance of the insulation — an R-value of 29 — on the inside. “Ripping up the roof to add exterior insulation is just not an option,” Jordan replies. Instead, he proposes making the rafters 7 inches deep and then adding two layers of R-15 mineral wool for a total of R-30. Drywall would be the air barrier, and the primer and paint would act as the vapor retarder. The consensus for exterior insulation, despite his objections to it, is emblematic of Jordan’s frustration. “This is unbelievable in that three different insulation contractors (all reputable) gave me three different opinions,” he says. One recommended R-19 fiberglass batt insulation with ventilation baffles. The second contractor favored two layers of rigid foam with two separate ventilation spaces. The third said he’d apply 2 inches of spray foam and “call it a day.” Why spray foam makes sense If there is no way to vent the area below the roof sheathing, as Jordan has indicated, leaving a gap between the insulation and the sheathing won’t help, and may be a problem, says Bill. “If someone suggested a ventilation space in an unvented ceiling assembly, then they probably don’t understand the physics of how the assembly actually works,” he adds. In an unvented “hot roof,” Bill says, the key is to keep moisture away from the sheathing, and the only reliable way of accomplishing that is with closed-cell spray foam. Bill has a shallow-pitch roof at his own house, and no way of venting it. He used 6 1/2 inches of closed-cell spray foam (R-38) for both air and vapor sealing, and he’s had no problems. An experienced spray foam installer is essential. The contractor that Bill used told him that temperature and pressure of the two agents that mix in the spray gun are critical. “He constantly adjusted these things throughout the job as he was applying the foam,” Bill said. “I had zero issues with improperly cured foam anywhere. I think you’ll find that if you use an experienced spray foam contractor you won’t have any problems.” What happens if the roof leaks? If Jordan were to go the spray-foam route, he wonders what would happen in the event of a roof leak. With a layer of impermeable foam coating the under side of the sheathing, where does the water go? This is the ceiling of the three-season room that Tom Jordan wants to insulate. Suggestions include closed-cell spray foam and a layer of exterior rigid foam. [Image credit: Tom Jordan]“You’re pretty much screwed if you get a roof leak,” Bill tells him. “The water won’t be able to get out, will pool up on top of the spray foam, and soak into the sheathing. You need to make sure your roof is properly flashed and sealed everywhere.” Bill suggests waiting a month or two before applying the foam, just to make sure there are no roof leaks. Every time it rained, Bill says he took a strong light and checked the sheathing for evidence of a leak. When he was sure there were none, he felt safe in adding the spray foam. The cut-and-cobble approach There are no takers on Jordan’s idea of stuffing the rafter bays with mineral wool for an R-30 ceiling and calling it good enough. For one thing, that amount of insulation is below code. What about putting two layers of 2-inch rigid foam between the rafters, and filling the rest of the cavity with R-15 of mineral wool? “I understand it does not meet code,” Jordan says, “but will it suffice? Do the 4 inches of rigid foam mimic what 4 inches of closed-cell spray foam would do?” Cutting sheets of rigid foam to fit between rafters or studs is called the “cut-and-cobble” approach, Bill says, and the only situation where it’s safe is in a vented roof. “With your unvented roof, a cut-and-cobble install will never seal well enough,” he says, “so you’ll end up with moisture getting to the underside of the sheathing, which is bad.” Further, Jordan’s view that spray foam is the “next asbestos” is unwarranted, Bill adds. “I really think you should reconsider your stance on spray foam,” he says. “As long as it’s installed properly, the cured foam is a very stable material. Worst case, it would be something like the old lead paint — safe unless you disturb it. Even asbestos is considered safe if it’s encapsulated and not disturbed.” Our expert’s opinion GBA Technical Director Peter Yost had these thoughts: Venting “flat” roofs: In order for venting to work, you need air flow — two holes and a driving force. It’s pretty easy to add two vents. The problem is the driving force. There simply is not enough air movement from wind, especially in low buildings, and there is really no stack effect. Can you mechanically ventilate? I have never seen this done in a way that does not make flat roof assemblies wetter rather than drier. It’s most often because there is no continuous air control layer between the insulation below and the vent space but it is also because setting up the sensors for controlling the mechanical ventilation is challenging. Solar reflectivity/absorptance of roof cladding: “Cool” roofs that reflect solar energy significantly reduce drying potential in most flat roof assemblies. Evaluating spray foam: Given what we know now about global warming potential (GWP), someone asked me the other day, would I have used closed-cell foam on the exterior of my house as I did in 2002-2007? In my exterior wall assembly, the closed-cell spray foam was my continuous water, air, and thermal barrier. That alone makes it pretty hard to give up on. And I know this Spotlight is about a flat roof, not a wall, but my point is that sometimes there is just so little else that can do the job. Additionally, closed-cell spray foam is now available with HFO blowing agents with a global warming potential (GWP) of approximately 1. That is a huge environmental footprint change for closed-cell spray foam. Having said that, spray foam is job-site chemistry. There are lots of variables to manage to get the chemistry right (for more, see this article from BuildingGreen). Finally, when applying spray foam inside a building, keeping the building unoccupied for 72 hours after application is a good idea. Air sealing: It seems as though just about every other Q&A on GBA hammers on airtightness, and in flat, unvented roof assemblies, you need to be fanatical about this. The lack of inherent drying potential of flat roof assemblies with membrane claddings means you’ve got to get the air control layer right. You might have a look at Joe Lstiburek’s article “Doubling Down: How Come Double Vapor Barriers Work?” While the assemblies he cites have worked, they are not the most robust and they are pretty dependent on solar heating. Double vapor barrier or not, get the interior air control layer right.last_img read more

Under-pressure Zidane thanks players

first_imgReal Madrid ‘The players know what they do, they don’t give up’ – Under-pressure Zidane thanks Madrid stars Joe Wright 02:49 1/28/18 FacebookTwitterRedditcopy Comments(2) Zinedine Zidane Cristiano Ronaldo Real Madrid 27012018 Getty Real Madrid Zinédine Zidane Valencia v Real Madrid Valencia Primera División Karim Benzema Los Blancos defeated Valencia 4-1 at the Mestalla to temporarily ease the pressure on their under-fire manager Under-pressure manager Zinedine Zidane congratulated his Real Madrid players for their performance following a valuable 4-1 win at Valencia on Saturday.The pressure on the head coach was eased at Mestalla as the champions claimed a hard-fought victory that takes them to within two points of third-place Valencia, who have played a game more.Two first-half penalties from Cristiano Ronaldo set the visitors on course for their first away win in LaLiga since October and fine late goals from Marcelo and Toni Kroos made the win safe after Santi Mina had given the hosts a lifeline. Article continues below Editors’ Picks Lyon treble & England heartbreak: The full story behind Lucy Bronze’s dramatic 2019 Liverpool v Man City is now the league’s biggest rivalry and the bitterness is growing Megan Rapinoe: Born & brilliant in the U.S.A. A Liverpool legend in the making: Behind Virgil van Dijk’s remarkable rise to world’s best player Zidane was delighted with the display, especially in the wake of Madrid’s Copa del Rey exit at the hands of Leganes this week, and suggested the result will help the squad to overcome something of a mental block.”I go away very happy,” he told a news conference. “We have to congratulate the players. We played an amazing game on a pitch that’s never easy, but we had to do it.”We did really well and we earned the victory, which was important. There are difficult moments and it shows the players have personality.”In football, a lot of things are in the head. The players know what they do, they don’t give up.”We interpreted the game very well tactically. They’re a direct rival and we have a game in hand. If we win, we’ll be above them.”In the second half, Keylor [Navas] saved us for 15 or 20 minutes, but we deserved the win overall.”Zidane also shrugged off Karim Benzema’s frustrated reaction to being substituted in the second half, adding: “Everyone is annoyed when they get replaced, but what matters is the result and Karim is happy.”SANTI MINA VALENCIA REAL MADRID LALIGAGoalkeeper Navas, who made an important save to deny Dani Parejo with the scores at 2-1, insists Madrid will not give up the chase in LaLiga despite them being 16 points behind leaders Barcelona.”We played a great game, which is the most important thing. We had to suffer in some moments but we didn’t lose personality and then the [late] goals came,” he said to beIN SPORTS.”The team has been playing well for a lot of games. It’s no secret that we’ve also played very badly, we know that. What we have to do is maintain consistency and we’re strengthened by matches like these.”Valencia are a great opponent, it’s at their home, the fans support them and they give everything, so it’s not easy. When you come to a place like that and you think they’re not going to create a single chance, you’re very wrong.”We know LaLiga is very difficult but we’re going to give everything. We won’t throw anything away. Whoever thinks we’re not going to fight in every match until the end to finish as high as possible is very wrong. We are Madrid.”last_img read more

How to Get Out of the Traffic Ghetto

first_imgThe challenge for magazine publishers now, he says, is to take a step up out of the magazine site ghetto into competition with the real Internet players.Perhaps the biggest trend in publishers’ online playbooks these days is social networking—that is, building their own Facebook or MySpace communities within their urls. Fast Company announced in February the relaunch of its site with user profiles—representing a full-blown stab at social networking. “Our aim isn’t to create an impersonal business social network,” proclaimed Mansueto Digital president Ed Sussman, “but to greatly enhance the level of business conversation in the nation.”Also in February, Variety launched the Biz, for better or worse its attempt at a Facebook-style community. And Martha Stewart added social networking features to marthastewart.com last year.New ToolsWikis have clearly made an impression on magazine publishers—even if some admit they still have no idea what one is. Sports Illustrated launched an ambitious archival project, the SI Vault, opening up its 54-year archive to users for linking video, photos, statistics, and, of course, the obligatory Wiki-ing. SI executives hope all the cross-linking and search engine optimization inherent in the Vault will add 5 million monthly unique visitors to the 6 million it currently averages.Like SI, other publishers have stripped away the paid or subscriber walls surrounding their archives, and have seen a healthy bump in traffic for their efforts. The Atlantic opened its archive to non-subscribers in January, and has seen a 15 percent increase in page views. Newsweek opened its archive last fall. The New York Times made headlines in September when it ended its premium archive subscription program, TimesSelect, and opened up most of its archive to the public. According to the Times, search traffic to archive pages has more than doubled since doing so.Donahue points out that other sites have eschewed the traditional—and complex—navigation in favor of a stripped-down, reverse-chronological, bloggy approach. Popular Science, ReadyMade and a slew of other sites have made such a transition in recent years. Other magazines, like Complex and the Fader, have abandoned the traditional magazine Web site altogether, replacing it with a single blog.Other magazines have gone with a simpler—decidedly less sexy—approach. Publishers in the food category, for instance, have retrenched to build out their recipe sections—what Donahue calls “a proven strategy built on the original user generated content play”—and it’s paid off. Reader’s Digest’s AllRecipes.com gets 30 times the page views of rd.com. BHG.com is also above 100 million page views, while Epicurious and MarthaStewart.com lean on recipe content to drive top tier traffic. As most publishers know, there always seems to be a precipitous amount of bad news hanging over the magazine industry (newsstand and advertising numbers down, paper prices up). Yet, if trade magazine box scores are to be believed, online traffic for all magazines—both consumer and b-to-b—continues to grow.But, like all industry trends, the numbers tend to be skewed by the rarified air of magazines above, say, 10 million monthly page views. Indeed, unless you have photos of Lindsay Lohan as Marilyn Monroe, chances are your traffic is sitting somewhere far below that figure—in, for lack of a better term, the “traffic ghetto.”“‘Every magazine tells me great things about their Web strategy,’” wrote Discover Media CEO Henry Donahue, quoting a reporter with whom he was eating lunch, in a recent post on FOLIOmag.com. “‘Then I go back to check their Nielsen traffic and they’re too small to be measured.’”Magazine sites “have grown in the past few years by executing against the basics-unique online content updated multiple times per day, blogs, photo galleries, video, podcasts, user-generated content,” Donahue, a former CFO of Primedia’s Lifestyles Magazine Group, continues. “At this point, though, those features are just the price of admission.” Traffic-Driving TrendsSocial Networking.Fast Company is making a notable attempt to supercharge its user profiles into a full-blown social networking site. Though not a consumer site, Variety is also trying its hand at being Facebook-ish.Blogification.Several sites are jettisoning old-fashioned magazine navigation in favor of a stripped-down blog approach. Check out PopSci.com and ReadyMade. Recipes.Not as sexy as social networking or blogs, but a proven strategy built on the original user generated content play. Reader’s Digest’s AllRecipes.com gets 30 times the page views of rd.com. BHG.com is also above 100 million page views. Epicurious and MarthaStewart.com are also in the topmost tier of magazine sites.SOURCE: Henry Donahue, FOLIOmag.comlast_img read more

Mentally challenged girl raped in Sirajganj

first_img.A mentally challanged girl was raped allegedly by a local youth in Joypura village of Shahjadpur upazila in Sirajganj on Friday, reports UNB.The accused is Momin Munna, 22, a college student and son of Amirul Islam of Joypura village.Officer-in-Charge of Shahjadpur police station said Munna pounced on the victim when she went to fetch a goat from the bank of the Jamuna river on Friday evening.As she was late to return home her grandmother went to look for her and found Munna violating her, but he eventually managed to flee.Being informed, village leaders tried to settle the matter in arbitration but failed.Later on Sunday victim’s father filed a case with Shahjadpur police station over the matter.last_img read more

Divideandconquer strategy key to fast protein folding

first_imgFor the fragments that contain stable hydrophobic contacts (which cause the protein to fold), the protein/computer enforces these contacts and adds more residues to enlarge these points. If new hydrophobic contacts are formed again, the process continues until no more contacts are found.“The protein doesn’t ‘know’ it has the right starting points at the early stages,” Dill explained. “It explores many possible avenues. But, we find that when the chain pieces have reached roughly the 16-to-24-mer stage, then the differences in free energy begin to become compelling, and structures begin to emerge fairly clearly.”In some cases, this zipping procedure alone is enough for a protein to reach its native form. For other cases, the ZA algorithm switches to the assembly procedure, combining two or more fragments to form additional structures until the native form is achieved. The ZA method was tested on nine small proteins, eight of which closely matched the experimental results of samples in the Protein Data Bank. The greatest sign that the ZA method is on the right track is its speed. For example, using ZA, protein G could fold in about 1 CPU year on a 2.8-Ghz Xeon Intel machine.“We don’t know exactly what the speed gain is,” Dill said. “Our largest protein studied is a 112-mer (subsequent to the PNAS paper). Currently the most extensive all-atom physical simulations on Folding@Home, with 100,000 processors, or IBM’s Blue Gene, built for this problem, are on smaller proteins, typically in the range of 20-40 amino acids long. However, those simulations are also more directed at physical questions of folding, rather than at protein structure prediction, so it’s hard to make a direct comparison.”Citation: Ozkan, S. Banu, Wu, G. Albert, Chodera, John D., and Dill, Ken A. “Protein folding by zipping and assembly.” Proceedings of the National Academy of Sciences, July 17, 2007, vol. 104, no. 29, 11987-11992.Copyright 2007 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Citation: Divide-and-conquer strategy key to fast protein folding (2007, August 6) retrieved 18 August 2019 from https://phys.org/news/2007-08-divide-and-conquer-strategy-key-fast-protein.html Researchers have found that proteins may use a divide-and-conquer strategy to fold into their native states in mere microseconds. The physical strategy, called “zipping and assembly” (ZA), can increase the speed at which supercomputers predict protein folding structures, greatly increasing scientists’ understanding of these building blocks of life. Explore further Ribbon diagrams of nine protein structures: Protein Data Bank structures are in orange, while Zipping & Assembly structures are in blue. Credit: Ozkan, et al. ©2007 PNAS.center_img The scientists, Banu Ozkan, Albert Wu, John Chodera, and Ken Dill from the University of California at San Francisco, have published their research in a recent issue of the Proceedings of the National Academy of Sciences. Their results show that the ZA search strategy provides a physics-based model of protein folding that could lead to advances such as computer-based drug discovery and genetic engineering.“Our research has two significant points, I believe,” Dill told PhysOrg.com. “First, it shows that all-atom physical force fields are pretty good (but not perfect), and may be useful for protein structure prediction. And second, it proves that zipping and assembly is a highly efficient conformational search method, and supports the view that ZA may be the physical mechanism of protein folding.”Proteins, which consist of an unstructured linear chain of amino acids, can fold into complex 3D structures within microseconds. On the other hand, high-speed supercomputers might take tens of years to compute the correct structure due to the vast assortment of possible forms the protein could take. When folded incorrectly, proteins can cause neurodegenerative diseases such as Alzheimer’s and mad cow disease. How proteins fold so quickly is a mystery that researchers are approaching from many different angles, including, for example, physics-based force fields. By assigning force fields to different parts of the protein, computers can track the movement of each individual part.Using the ZA strategy, Ozkan, Wu, Chodera and Dill have sped up the rate at which computers using force fields can predict protein structures. In the ZA model, the first step that proteins (or computers) take is breaking the amino acid chain into 8-12 fragments to search for a very small fraction of favorable folding points (traditional methods usually search the entire chain).“The speed gain in our method comes from not exploring all possible folding routes, but instead from following only those routes that entail small conformational search steps,” Dill explained. “This reduces the search problem, in principle, from one that grows exponentially with the chain length to one that, instead, grows only as the first or second power of the chain length. While we haven’t actually proven that quantitatively, it is clear that the method is much faster than brute force Monte Carlo or molecular dynamics.” Parsley and dill help fight cancer, research shows This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more