Origin of life theorists face a much higher “Mount Improbable” seeing a minimal cell with 473 genes.Craig Venter’s team has published results of their latest attempt to strip down a living cell to bare essentials (the organism must be free-living, not parasitic). They’re calling it “Syn 3.0.” After years determining what a version of Mycoplasma mycoides bacterium could do without, they came up with a “synthetic” cell containing 473 genes deemed essential. They could not determine the function for 149 of the genes.It’s the talk of the town in science news circles, because Syn 3.0 is much more complex than any proposed protocell emerging from a chemical soup. On his blog Darwin’s God, Cornelius Hunter remarks, “Mycoplasma mycoides Just Destroyed Evolution.” Here are some media headlines:Artificial cell designed in lab reveals genes essential to life (New Scientist)Synthetic bug given ‘fewest genes’ (BBC News)Creation of minimal cell with just the genes needed for independent life (Science Daily)‘Minimal’ cell raises stakes in race to harness synthetic life (Nature News)Tiny Artificial Life: Lab-Made Bacterium Sports Smallest Genome Yet (Live Science)Microbe with stripped-down DNA may hint at secrets of life (PhysOrg)Science Magazine published the original research by Hutchinson, Venter et al. Commenting on the paper for Science, Robert F. Service says the organism has “fewest genes” but “many mysteries.” Venter’s team first tried to strip down their earlier bug, Syn 1.0, but the complexity of the cell stumped them.In their current work, Venter, along with project leader Clyde Hutchison at JCVI, set out to determine the minimal set of genes needed for life by stripping nonessential genes from Syn 1.0. They initially formed two teams, each with the same task: using all available genomic knowledge to design a bacterial chromosome with the hypothetical minimum genome. Both proposals were then synthesized and transplanted into M. capricolum to see whether either would produce a viable organism.“The big news is we failed,” Venter says. “I was surprised.” Neither chromosome produced a living microbe. It’s clear, Venter says, that “our current knowledge of biology is not sufficient to sit down and design a living organism and build it.”They started over with a “top-down” approach. Beginning with Syn 1.0, they systematically stripped out anything the bacterium could live without. They got it down to 473 genes, about half the size of their Syn 1.0 organism.The big news is that so many genes are essential, and that 149 of the essential genes have unknown functions. New Scientist quotes a biochemist in the UK:“Finding so many genes without a known function is unsettling, but it’s exciting because it’s left us with much still to learn,” says Alistair Elfick, a bioengineer at the University of Edinburgh, UK….“If we’re already playing God, we’re not doing a particularly good job of it,” Elfick says. “Simply streamlining what’s already in nature doesn’t seem very God-like and, if anything, is a very humbling exercise.”Venter also felt the humility vibes, according to Live Science:“We’re showing how complex life is even in the simplest of organisms,” said Craig Venter, founder and CEO of the J. Craig Venter Institute (JCVI), where the study was completed. “These findings are very humbling in that regard.”From an intelligent design perspective, Ann Gauger explains in Evolution News & Views why this organism (and any protocell) is irreducibly complex:All of this leads to an obvious question. This little bacterium has to be able to copy its DNA, transcribe and translate it into protein, plus be able to coordinate all the steps involved in cell division. It has to be able to make all the things it can’t get from its environment. That’s a lot of information to be stored and used appropriately. Hence 473 genes.This puts pressure on the origin-of-life field.But where did the cell come from in the first place? It’s a chicken-and-egg problem. Given the number of things the cell has to do to be a functioning organism, where does one begin? DNA or RNA alone is not enough, because protein is needed to copy the DNA and to carry out basic cellular processes. But protein is not enough by itself either. DNA is needed to stably inherit the genetic information about how to make proteins.It’s like a car, Gauger says. It needs “engine, a transmission, a drive shaft, a steering wheel, axles and wheels, plus a chassis to hold it all together,” to say nothing of gas and a starter. If you get only one or two of those things, you have a piece of junk, not a transportation machine.Take just protein synthesis. An article on PhysOrg explains that having the building blocks is not enough. The protein recipe “requires precise timing” as well. The steps are “precisely choreographed” analogous to a ballet or a recipe in the kitchen.In fact, details about the splicing step just came to light in a paper in Science Magazine. Just one subcomplex “must dock onto the rest of the spliceosome and hints at the structural changes the complex must go through to form the mature spliceosome.” This matures the messenger RNA before it goes into the ribosome to be translated into a protein. Summarizing the find for Science, Jamie H. D. Cate calls it a “big bang in spliceosome structural biology.” Splicing occurs in eukaryotes, which evolutionists think evolved later than bacteria. Even so, numerous proteins are involved in handling DNA and RNA in the simplest living organisms, including Syn 3.0.According to PhysOrg, lead author Hutchinson said that the genome in their minimal cell is “as small as we can get it and still have an organism that is … useful.” Even so, the bacterium lives in the comparative comfort and safety of the lab. Would it survive in the wild? Most cells live in ecological communities with other cells in complex food webs. How would the first protocell get along in a sterile world before life?Live Science posted a somewhat humorous slide show about theories for the origin of life – humorous, because none of them work. Opening with Darwin and Oparin’s speculation about a primordial soup, Charles Q. Choi’s list includes:Electric spark (Miller experiment)Clay (Alexander Cairns-Smith’s favorite hypothesis)Deep-sea vents (Michael Russell’s model)Chilly start (obviously at odds with the above models, but needed to protect from UV rays)RNA World (a dead idea according to leading theorists)Simpler beginnings (“garbage bag world” or “lipid world”)Panspermia (Francis Crick’s escape; it just pushes the question farther out to space)Each of these models has its supporters and detractors. Some are mutually exclusive. One party tries to start with metabolism, but no genetics. Another tries to start with genetics (RNA World), but no protein. Some like it hot, some like it cold. RNA was the leading hope that a molecule could emerge by chance that could begin evolving by Darwinian natural selection. Without natural selection, all agree that lucky accidents would have to occur by chance.Susan Mazur rubbed shoulders with the leading origin-of-life theorists in the world at their conferences and institutions. Her 2014 book, The Origin of Life Circus, contains eye-opening interviews with the biggest authorities. All of them disown the well-known “RNA World” scenario, at least in its original formulation, despite its continuing presence in the media. Some think RNA had a role in combination with other molecules like proteins. But relying on proteins and other molecules undermines the whole reason for the RNA World, to try to account for metabolism and genetics in one molecule. Steven Benner, for instance, lists four paradoxes of RNA: (1) the building blocks tend to form tar, (2) RNA can’t form in water, (3) RNA polymerization goes against thermodynamics, (4) ribozymes are more likely to destroy RNA than build it (pp. 155-156). The bottom line is that RNA could not have worked alone. It needed proteins as helpers, as well as a container or membrane to hold everything together.The problem with proteins and polynucleotides is getting the sequence right. Even if they could join up easily (which they don’t), unless they can actually do something, they cannot be building blocks to a living organism. As many have pointed out (including our online book), the probability of getting functional sequences under ideal conditions is infinitesimally small. If one usable protein would never form on Earth in the entire history of the universe, how much less 473 proteins in Venter’s minimal living cell? Each person interviewed in Mazur’s book sang the same refrain: we have no idea how life arose.Materialists, come to your senses. It’s hard to kick against the goads. The reality of life is telling you something. It’s shouting. Why resist any longer? You respect evidence, don’t you? Faith in the impossible runs against your values. Follow the evidence where it leads. It’s the scientific thing to do. (Visited 118 times, 1 visits today)FacebookTwitterPinterestSave分享0
South Africa’s 3 000 kilometres of coastline holds many treasures, unspoilt places hidden from mainstream tourists. Read more to discover the secret beaches all over the country.Noordhoek’s Long Beach is one of the secret beaches on the Cape Peninsula of South Africa. (Image: Noordhoek Tourism)Brand South Africa reporterWith a coastline of 3 000km, South Africa has enough beaches to accommodate thousands of sun lovers without ever getting crowded. The beaches near the larger coastal cities get most visitors, of course, and in high summer bathers might have to negotiate a tangle of tanned limbs to get from the sea to their towels.But there are dozens of other beaches along the country’s coastline where you can find space, privacy, soft sand and clear blue waves.Cape West CoastIf you want to avoid Cape Town’s main beaches, head up the west coast towards Namibia and you’ll find one spectacular seascape after another. The coastline has stunning wind-lashed scenery and may at times look dry and barren. But in spring the region’s world-famous wild flowers transform the area into a magic carpet of colour.The long white beaches and rocky outcrops provide some of the most private beaches, not to mention best surfing waves. Secret places to visit include Eland’s Bay, Paternoster, Lambert’s Bay and Yzerfontein.In summer you can enjoy fresh crayfish at reasonable prices in local eateries. As this side of South Africa is on the Atlantic Ocean, the water is a lot colder than in the warm Indian Ocean to the east. But that doesn’t stop swimmers from enjoying a bracing dip.Cape PeninsulaWhile the fashionable Cape Town beaches – particularly Camps Bay, Clifton and Llandudno – are overrun in summer, visitors can still find sandy solitude. Noordhoek’s Long Beach is a serene sweep of sand over 2km long, backed by beautiful fynbos- covered mountains.Sandy Bay, just next to Llandudno, is similarly isolated and lovely, as long as one doesn’t mind the nudists for which this beach is notorious.Blaauwberg offers the best views of Table Mountain and is long enough to avoid people, if that’s what you’re after. Or travel just a little way to the dune-fringed beauties of Betty’s Bay, Kleinmond and Pringle Bay.Cape East CoastEast of Cape Town, the coastline offers one sleepy seaside town after another, each with its own personality and beaches. Here the Indian Ocean laps the continent with its warm coastal currents. The further east you travel from Cape Town, the warmer the sea gets.Hermanus is a popular weekend and holiday spot, and the beaches can be crowded. But a five-minute drive out of the village takes you to the more peaceful Grotto Beach.Follow the coastline north and the gems of Gansbaai, Pearly Beach and Arniston beckon. Arniston, a restored fishing village, is particularly beautiful, and out of season is all but isolated.Eastern CapeThose allergic to crowds will want to avoid the seaside havens of Plettenberg Bay, Knysna and George in high season, but again there are beaches just out of town that offer space and scenery aplenty.Port Elizabeth and East London have places of historic interest as well as some good swimming spots. East London’s Gonubie Beach is one of the country’s prettiest, as yet unclaimed by hordes of beachgoers.Cape St Francis and Seaview Game Park, both near Port Elizabeth, are similarly untrammelled.The Wild CoastFormerly known as the Transkei, this is a breathtakingly beautiful region. It has many remote, rural locations offering unspoiled velvet-green hills and pristine beaches.Some parts are harder to access, but places with facilities include Mazeppa Bay, Coffee Bay, Hole-in-the-Wall, Trennerys, Mngazi and Presley Bay.Locals are friendly and hospitable and these are ideal holiday resorts for those wanting nothing more than a beach, a few good surfing waves and perhaps the odd fishing trip.Read more: Discover South Africa’s Wild CoastKwaZulu-NatalNestled between the Indian Ocean and the Drakensberg mountains, KwaZulu-Natal is hot, humid and subtropical. These are the best beaches for those who like to float in the sea for hours on end, and the mild temperatures in winter make it an all-year- round holiday destination.Durban’s beaches can leave one jostling for elbow room in season and nearby towns such as Southbroom and Ballito have recently exploded with holiday homes, but you don’t have to go far to avoid the crowds.On the north coast, near the Mozambique border, is the ecotourism paradise of Kosi Bay, a pristine estuary surrounded by lush marsh forest, mangrove, ferns and orchids. Take a walk between tanning sessions and you could spot a hippo, a crocodile or a loggerhead turtle.Nearby St Lucia, a protected nature reserve and one of South Africa’s seven World Heritage sites, has beautiful long beaches and lukewarm water.Other secret spots include Mtunzini, Zinkwazi and Blythedale. The south coast beaches aren’t quite as isolated, but small towns such as St Michaels, Hibberdene and Umkomaas are less inhabited, particularly in the mild winters.This is an edited version of an article first published by South African Tourism.Would you like to use this article in your publication or on your website? See Using Brand South Africa material.
Tags:#start#tips Why Tech Companies Need Simpler Terms of Servic… Children’s literary character Pollyanna is supposed to teach the value in maintaining a super sunshine-filled attitude. The lesson echoes, perhaps, the notion that “If you don’t have anything nice to say, don’t say anything at all.” Social pleasantries aside, this is probably no way to run your business. And in a recent blog post, VC Ben Horowitz agrees, cautioning CEOs against falling into the trap of being too nice and too positive. “Tell it like it is,” he advises.Horowitz describes his own decision to stop being too positive as his “single biggest personal improvement as CEO.” He shares some of his early experiences leading a company, recognizing the pressures that he felt and the way in which he tried to shoulder the burdens of business setbacks himself, rather than transferring some of that burden to his employees. Thinking that that would make the problems worse, “I thought I should project a positive, sunny demeanor and rally the unburdened troops to victory. I was completely wrong.”Employees, contends Horowitz, have a pretty nuanced understanding of the reality of situations. By “blowing sunshine,” he was actually doing more damage than good. By keeping negative information to himself, he was failing “to give the problem to the people who could not only fix it, but would be personally excited and motivated to do so.”Horowitz lists three reasons why it’s imperative that CEOs be honest and transparent.1. Building TrustIf you trust someone, then you don’t really need additional explanation or justification for a particular course of action. But if there’s no trust, then no amount of communication or reasoning can really make an impact. And “without trust,” writes Horowitz, “communication breaks.” As communication gets to be increasingly challenging a company grows, Horowitz argues that it’s vital a CEO develop the employees’ trust. “A CEO’s ability to build this trust over time is often the difference between companies that execute well and companies that are chaotic.”2. Deploying Your Company BrainpowerIn order to build a tech company, you have to hire a lot of smart folks. And it’s a waste to not take advantage of that brainpower to solve companies problems. “A brain, no matter how big, cannot solve a problem that it doesn’t know about.”3. Building a Problem-Solving Company CultureBad news travels fast, as the old adage goes. Good news tends to travel a lot more slowly. As a result, employees at failed companies often have known about the fatal problems long before companies have floundered. But, as Horowitz observes, the company culture in these situations frequently discourages people to spread bad news – and by extension, to address the problems. A healthy company, on the other hand, encourages people to discuss problems openly and freely. “Build a culture which rewards – not punishes – people for getting problems into the open where they can solved.” This may involve countering some old management maxims such as “don’t bring me a problem without bringing me a solution.” Horowitz admits that there are “overwhelming psychological pressures to be overly positive.” But he encourages CEOs to stand up to these pressures and to be honest – even if it means sharing unpleasant news. Related Posts 8 Best WordPress Hosting Solutions on the Market audrey watters A Web Developer’s New Best Friend is the AI Wai… Top Reasons to Go With Managed WordPress Hosting
Start Free Trial Already a member? Log in Building science experts, architects, engineers, and builders from across the U.S., Canada, and Europe gathered in early August in Westford, Massachusetts, for the 19th annual Westford Building Science Symposium, a conference sometimes known as “Summer Camp.”Over three lively days filled with education, networking, and drinking, experts gave ten presentations on a variety of building science topics. You read it here first GBA readers who attended the conference had a sense of déjÃ vu at three of the presentations, since the talks covered topics that GBA has reported on in depth: Ventilating high-rise apartment buildings Lorne Ricketts, a building science engineer at RDH Building Engineering in Vancouver, British Columbia, gave a presentation on research into ventilation systems in a high-rise multifamily building. (Ricketts and his co-author, John Straube, also reported their findings in a paper titled “Corridor Pressurization System Performance in Multi-Unit Residential Buildings.”)For multifamily buildings, mechanical engineers often specify a type of supply ventilation system called a “corridor pressurization” (or “pressurized corridor”) system.Ricketts explained, “A pressurized corridor ventilation system is designed to provide ventilation to the entire building.” This type of ventilation system includes several components:An illustration of a corridor pressurization system is shown in Image #4, below.The engineers who design these supply ventilation systems make several assumptions. The two most important of these assumptions are (a) that the air introduced by the roof-mounted fan is delivered to the common corridors, and (b) that the pressurized corridors deliver fresh air to each apartment. Both assumptions are probably wrong.It turns out that this is a faith-based ventilation system. The designers’ faith is misplaced. Let’s make some measurements While corridor pressurization systems are fairly common, few researchers have measured the airflows… This article is only available to GBA Prime Members Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.