December 19

Sweet Solutions from Nature

first_img1.  Rammensee, Slotta, Scheibel and Bausch, “Assembly mechanism of recombinant spider silk proteins,” Proceedings of the National Academy of Sciences USA, published online on April 29, 2008, 10.1073/pnas.0709246105.In the alligator story, National Geographic noted that alligators have “innate” immune systems while humans have “adaptive” immune systems.  “Although innate immunity is often considered primitive, there is nothing primitive about its effectiveness, [Adam] Britton [biologist, northern Australia] said.”  Britton called the antimicrobial peptides in alligator serum “extremely effective agents” against bacteria.  Remember that the first extremely effective antibiotics were also found in a “primitive” organism – fungus.  Design follows design, not chaos.  Imitation is the highest form of flattery.(Visited 7 times, 1 visits today)FacebookTwitterPinterestSave分享0 Human engineers continue to look at plants and animals for inspiration.  Biomimetics – the imitation of biology for design technology – shows no sign of running out of ideas.Sweet gas:  A spoonful of sugar in the gas tank?  Science Daily reported on progress in converting plant sugars into clean-burning hydrogen – using biological enzymes.  This could give a new meaning to “power plant.”Moooove on:  Speaking of enzymes, fuel technicians have isolated an enzyme in a cow’s stomach that shows promise for efficient conversion of plant sugars into ethanol.  Science Daily’s gut reaction to this story was positive: “The fact that we can take a gene that makes an enzyme in the stomach of a cow and put it into a plant cell means that we can convert what was junk before into biofuel,” said one professor of crop and soil science.See ya sooner, alligator:  Yuck: alligator blood.  What good could come from that?  Infection-fighting drugs, reported National Geographic News.  Scientists are intrigued that alligators live with frequent bloody wounds in bacteria-laden muddy swamps but rarely get infected.  Scientists at Louisiana University found that alligator serum fights more bacteria than human serum.  If we can harness the alligator’s secrets, said one researcher, “we could be on the verge of a major advance in medical science.”Drag queen:  The dragline silk of spiders continues to be a holy grail for materials scientists.  A German physics team reported in PNAS some initial success in getting the proteins to assemble into fibers.1  To do it, they squeezed the proteins through tiny orifices similar to the spinnerets on a spider’s abdomen.  The BBC News published a report about it.  Spiderman, here we come.last_img read more

December 18

‘I only ever wanted to dance’

first_imgMichaela DePrince sizzles during a photo shoot in Johannesburg.(Image: Herman Verwey, City Press-Media24) The confident teenager is tipped for international stardom.(Image: Janine Erasmus) DePrince’s interpretation of Gulnare in Le Corsaire was well received by critics and reviewers.(Image: Susanne Holbaek)MEDIA CONTACTS • Samantha SaevitzonSABT publicity and publications officer+27 11 877 6894RELATED ARTICLES• They come to dance…and grow• Major turnaround for SA ballet• Using theatre to educate• SA puppet company wins a TonyJanine ErasmusTeenage ballet dancer Michaela DePrince survived a brutal civil war, adapted to a new life in a faraway country, and overcame numerous challenges to excel in a white-dominated art form. Today she’s regarded as one of the US’s most promising young artists.DePrince is African by birth, born in the West African country of Sierra Leone in the middle of a devastating civil war. Still not old enough to go to school, she ended up in a refugee camp as one of thousands of war orphans.Her bleak existence there – compounded by a skin pigmentation condition called vitiligo – was sustained by a torn-out magazine picture of a ballet dancer that somehow found its way into the camp and into her hands, and she decided there and then that she wanted to be like the happy girl in the picture.DePrince and two other girls from the orphanage were adopted by an American family and with their love and support, and with the help of her dancing, she was eventually able to put her wartime experiences behind her, although it took time and hard work and the memories have never gone away entirely.Today the 17-year-old is poised and assured, a mindset that belies her turbulent past, but gives a clue to why she is where she is today. She knows what she wants, and she’s prepared to do everything possible to get it.“I’ve only ever wanted to dance,” she says, and that determination has carried her in a discipline where competition is ruthless and discrimination has the potential to curtail many a career.Professional debut in JohannesburgSo compelling is her talent that the South African Ballet Theatre’s (SABT) Dirk Badenhorst invited DePrince to make her professional debut with the Johannesburg-based company in July, dancing the role of Gulnare in the local premiere of Le Corsaire.The ballet was presented by the South African Mzanzi Ballet, a new company formed through the merger of Mzansi Productions and the SABT. It was produced by former SABT principal dancer Angela Malan after the style of Marius Petipa, who set the standard for all modern interpretations of the ballet.DePrince had just two weeks to learn the role and she then had to make the transatlantic journey alone, as her parents were busy looking after her siblings.“To come all this way to work with an unfamiliar ballet company, not knowing anyone, and not knowing what you were walking into, took a lot of courage,” says Iain MacDonald, the SABT’s artistic director. “But the minute Michaela walked in, it was like she was one of the family.”“I didn‘t even know that South Africa had a ballet company,” says DePrince, “but I’ve had the time of my life here.” She plans to return some time in early 2013.Her performance as the slave girl Gulnare was widely praised, with reviewers describing her interpretation as “beautifully executed” and her line and balance as “near-perfect”.“I also learned a lot from Burnise,” she says, referring to the vastly experienced principal dancer Burnise Sylvius, a Pretoria girl who has guested with ballet companies from Canada to Hong Kong, and danced the role that DePrince most aspires to – that of Aurora in Sleeping Beauty, a role renowned for its technical difficulty.A new beginningEarly on, DePrince showed a strong aptitude for ballet. “My mom got me The Nutcracker on DVD, and I learned all the moves off by heart.”At a live performance of the same ballet, she was able to accurately point out where the dancers were making errors – without having taken a single lesson herself. Her mother enrolled her in a dance class in Philadelphia where they lived, and she flourished, dancing en pointe at the age of seven, and forging a career despite the efforts by some of her earlier teachers to discourage her.Now photos of her exuberant grands jetés and lively smile garner comments like “bellissima!” and “spectacular!” but when DePrince was growing up there was seemingly no place for a black dancer in the pastel world of American ballet.But she followed the advice she now gives to other aspiring young dancers: to never give up and follow your dream relentlessly.“There were times that I wanted to pack it in, but my mom said, ‘wait until the end of the year’ or ‘give it a little longer’, and that helped me to get over the wall.”The family has since relocated to New York so that DePrince and her sister Mia, a talented singer, can pursue their careers. Those with sharp eyes may notice that many of DePrince’s ballet shoes have been dyed – by her mom – to complement her skin.DePrince recently completed a scholarship at the Jaqueline Kennedy Onassis school of the American Ballet Theatre. She joins the renowned Dance Theatre of Harlem in August.“I had a few offers, but I wanted to join the Harlem company because they’ve done so much to pave the way for black dancers.”South African Laveen Naidu is currently Harlem’s executive director. He started off by studying South Indian classical dance in his hometown of Durban, and went on to graduate from the University of Cape Town’s ballet school. In 1991 he received a scholarship from the Dance Theatre of Harlem, and has never looked back.DePrince was also one of the six young stars of the 2011 documentary First Position, which follows dancers throughout their preparations for the Youth America Grand Prix, a prestigious international student dance competition.Giving talented kids a chanceMacDonald runs the SABT’s outreach programme, which is active in several areas of Johannesburg, including Soweto, Sophiatown and Alexandra. Children between six and 16 years of age receive free lessons to a standard that allows them to take examinations, and progress. According to MacDonald, this initiative has paid off handsomely.“There’s no question that we have talent,” he says, “but it’s opportunities that these kids need. Ballet gives them more than just a workout, it helps them to become more self-confident and disciplined, and this spills over to other areas in their lives.”DePrince was able to interact with the young dancers at the SABT’s Alexandra dance school and, says MacDonald, she was an inspiration.“The kids were a bit unsure and in awe when she walked in, but they warmed to her very quickly.”The development programme has seen a number of successes, most notably the award-winning Andile Ndlovu, who now dances with the Washington Ballet, and returned home to appear in Le Corsaire.Children from the development programme are regularly exposed to professional productions, either performing or watching, and some of them also appeared in Le Corsaire.THis is what DePrince loves to see. She hopes to be a role model for other young girls, especially those with the disadvantages that she overcame, and to inspire them to set their sights firmly on their dreams.last_img read more

December 18

Rhinos in Boucher’s safe hands

first_imgHaving retired from his active cricket career in mid-2012, Boucher asserted that he will now focus all of his energy to saving South Africa’s rhinos.(Image: Mark Boucher) Micro-chipping the rhinos and collecting the DNA for a database will go a long way towards saving the animals from decimation.(Image: SAB) MEDIA CONTACTS • Mark Boucher   SAB-Boucher NPC  +27 11 881 84 17  RELATED ARTICLES • Using technology to fight poaching • A legacy for the African rhino • Giving rhinos a voice through art • Sangomas join the rhino force • Taking the plunge for our rhinos • Special anti-poaching weapon for SA • Musos pitch in to save rhinosCadine PillayFollowing a severe eye injury which forced his early retirement, former Proteas wicketkeeper Mark Boucher has gloved up for rhinos – the cricket star has decided to devote his time to rhino activism as South Africa battles with escalating poaching figures.Boucher and South African Breweries (SAB) launched the non-profit SAB-Boucher Conservation in October this year. Boucher was appointed by SAB as its Castle Lager rhino ambassador, to raise funds for rhino conservation both locally and abroad through the Our Rhinos in Safe Hands campaign.Having retired from his active cricket career in mid-2012, Boucher asserted that he will now focus all of his energy on the new partnership. The former Protea played 147 test matches and 295 one day internationals for South Africa, taking 999 dismissals behind the stumps and one wicket as bowler, in all forms of the game – his 556 test dismissals is still a world record. “I now have the opportunity to contribute something meaningful towards a cause that is close to the hearts of my fellow South Africans.” Boucher said at the launch.“This type of partnership can make a positive contribution if we focus on a tangible contribution to the larger rhino conservation effort.”The SAB-Boucher partnership aims to raise enough money to register all of South Africa’s 18 000 rhinos on a national rhino DNA database.SAB was involved in the setup of the organisation with a donation of R300 000 (US$34 000) but the ultimate goal is to raise at least R1-million ($113 000).Micro-chipping and DNARhoDIS (the Rhino DNA Index System) was established and is run by Veterinary Genetics Laboratory at the University of Pretoria.A DNA database is an essential element in the fight against poaching. If the origin of the horn is unknown, it makes tracking the illegal trade very difficult. If trade is legalised, as many argue is the only sustainable solution to the poaching problem, then the DNA database will be central to managing it.“Micro-chipping the rhinos and collecting the DNA for a database will go a long way towards saving the animals from decimation,” Boucher said.“There are so many passionate people out there fighting rhino poaching every day, and yet we don’t seem to be winning the battle.”When a police raid results in the arrest of poachers, those in possession of rhino horns, or the actual traffickers, the DNA database will go a long way towards giving authorities more ammunition against criminals.It will prove that horns seized from suspects can be traced to a particular country and conservancy, and will help to establish when the animal was killed; this makes a much stronger case in the courts.“Our passion for the country’s natural environment motivated us to join forces with Mark Boucher to single-mindedly focus on the DNA database as one of the key pillars required for a sustainable solution to rhino poaching,” said SAB executive director Dr Vincent Maphai.SAB has micro-chipped and collected DNA samples for the database since 2004 and 77 rhinos have received microchip insertions and had DNA samples extracted to deter poachers.Other players get on boardSupporters of SAB-Boucher Conservation include Archbishop Emeritus Desmond Tutu, former cricket administrator Dr Ali Bacher, former SANParks CEO Mavuso Msimang, renowned conservationist Dr Ian Player, and scientific officer of the African Rhino Specialist Group Dr Richard Emslie.Poaching figures for 2012 have already surpassed all past records, with 570 rhinos killed this year alone in South Africa.SAB-Boucher Conservation will initially focus on its most pressing concern, namely the safety of South Africa’s rhino, but is later expected to direct its efforts to other threatened species, whose DNA will also be entered into the database.last_img read more

December 16

Air Flow Pathways in a Leaky Exterior Wall

first_imgThe leaking air was moving laterally through the battNow, let’s focus in on where the dirt appeared in this batt. Let’s observe. See that part in the red box (Image #3, below)? That indicates air was moving laterally across the stud cavity in the wall. What?!Yes, it’s true. When I first looked at the batt, that pattern didn’t stand out. I saw it only later when I looked at the exterior wall sheathing and saw the pattern repeated there. See the band of dust near the bottom of the cavity in Image #4, below? That’s where the fiberglass batt picked up that band of dirt in the red box in the previous photo.But how is air moving laterally across the stud cavities? Well, we know that air needs two things to move: a pressure difference and a pathway. It also likes to take pathways with lower resistance. So that band of dust on the sheathing is a pathway of lower resistance. You can see the pathway better in Image #5, below.The fiberboard sheathing is bucklingThe sheathing that I discovered in the wall is asphalt-impregnated fiberboard, commonly referred to as Celotex, one of its primary manufacturers. It’s not as stiff as plywood or OSB, and you can see below that it’s not lying flat against the studs. Those gaps create pathways.OK, that explains air moving inside the cavity, but is it connected with air outside the building enclosure? Some people think just the presence of fiberglass is the problem. They’re wrong. The answer is shown in the Image #6, below. The seam between two pieces of fiberboard is open. You can even see what’s on the other side: the brick veneer.It looks like that nail missed the stud. It was probably OK at first, but over the past 46 years, the fiberboard has distorted through a whole lot of wetting and drying cycles. The result is a hole in our building enclosure. And there are more holes everywhere two pieces of the fiberboard meet and at the top and bottom of the wall. That adds up to a lot of leakage area.Where’s the WRB?Also, the fact that I can see the brick veneer on the outside of the building means there’s no drainage plane. No felt. No house wrap. No nothing between the fiberboard and brick. Fortunately, I haven’t found widespread moisture damage resulting from this. (The termite damage is an indication of moisture but it was isolated to the two sides of the window.)How do you fix this? You’ve got several options. You could ignore the problem and put it back together the way you found it. You could spray-foam the whole thing. You could seal the gaps and install fiberglass batts again. I’ll show you my solution next time.By the way, demolishing a bathroom by yourself is a heck of a lot of work. I hauled out 47 bags of debris and a few larger items. The good news is that by the time my wife returned home the following week, I was done with 98% of the demolition. The last photo shows what she found when she walked in there expecting to find the same bathroom she’d left the week before.Lead-safe work practicesNow let me end with a caveat. If your home was built before 1978, it probably has lead paint in it. If you’re doing the work as a homeowner, you’re not subject to the rules of the Renovation, Repair, and Painting (RRP) Program, which applies to contractors, but you you should still work safely. Here are their lead guidelines for do-it-yourselfers. I followed them pretty closely when I was doing the demolition in my bathroom. Allison Bailes of Decatur, Georgia, is a speaker, writer, building science consultant, and the author of the Energy Vanguard Blog. Check out his in-depth course, Mastering Building Science at Heatspring Learning Institute, and follow him on Twitter at @EnergyVanguard. This spring I spent a lot of hours in my bathroom. I was sick. Really. I was sick and tired of having an outdated bathroom that was falling apart. So when my wife hit the road one Monday in late April to drive across the country, I got out my wrecking bar. The lead photo shows what it looked like at the end of my first full day of demolition.I opened up the plumbing wall first. Lots of fun stuff, there. But the real fun came when I opened up the exterior wall. The four termite-damaged studs were part of that fun, but something else was even better.Yogi Berra once said, “You can observe a lot by just watching.” So when I got into the exterior wall, I watched. I live in the Atlanta area in a condo built in 1970. Air leakage hadn’t been discovered yet back then, but that doesn’t mean it wasn’t happening. Check out that fiberglass batt (first two images below) from the exterior wall.Do you see what I see? The black parts are where the fiberglass captured dirt. The dirt was traveling in air that was moving in the wall. Fiberglass is a great indicator of air leakage, and most of the fiberglass manufacturers make it easy for us to see the dirt. They make their product in light colors: pink, yellow, white. (There’s a new trend toward brown fiberglass, though, which isn’t helpful for spotting air leakage. But hey, we’re making airtight houses now, right?) RELATED ARTICLESQuestions and Answers About Air BarriersOne Air Barrier or Two?Is OSB Airtight?Airtight Wall and Roof SheathingBlower Door BasicsPinpointing Leaks With a Fog MachineAir Leakage Through Spray Polyurethane FoamGetting the Biggest Bang for Your Air-Sealing BuckAir-Sealing Tapes and GasketsAir Sealing With Sprayable Caulk New Air Sealing Requirements in the IRCNavigating Energy Star’s Thermal Bypass ChecklistVideo Series: Attic Air SealingGBA Encyclopedia: Air BarriersGBA Encyclopedia: Addressing Air LeaksManaging Lead Paint Hazardslast_img read more