first_imgNigel Williams tried to explain in Current Biology1 why “size matters” among marine iguanas in the Galapagos Islands: the vectors of natural and sexual selection don’t always line up.  Females appear to like the big males when times are good, but when drought comes, the smaller dudes do better.    There’s a difficulty with such investigations.  Even though this habitat was a “rich source of information for Charles Darwin when developing his theory of evolution,” the article admits that “Factors influencing the evolution of complex traits such as body size are notoriously difficult to study but a new review of work on marine iguanas in the Galapagos islands suggests an answer may lie in the interplay of natural and sexual selection” (emphasis added).1Nigel Williams, “Size matters,” Current Biology, Volume 15, Issue 18, 20 September 2005, Page R742.Why should Darwin be mentioned in this article, except as a historical embarrassment?  There is no evolution here.  Heap big iguana is still iguana as much as peewee.  Size is not a “complex trait” in the sense of evolving wings or some new organs; it is just a modification of parts already present.  There is no long-term evolutionary trend here, but rather only oscillations around a mean that reflect climate conditions – otherwise we should see iguanas the size of Godzilla by now.  If natural and sexual selection work against each other, then stasis rules, not evolution.  Charlie won’t get anywhere with slippage on the treadmill (see 03/17/2003 entry).(Visited 6 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more


first_imgWood is a renewable fuel and, assuming that new trees grow up to replace those cut for firewood, it is carbon-neutral, meaning that it doesn’t have a net contribution to global warming. That said, wood burning also churns out a lot of air pollutants, some of which are highly visible as smoke. Fortunately, there’s a lot we can do to reduce the pollution generated by wood burning—and boost the efficiency.Our discussion here focuses mostly on wood stoves; pellet stoves and larger central-heating wood boilers will be covered in future columns. Fireplaces, for the most part, shouldn’t be thought of as heating systems. They are aesthetic features that can add wonderful ambiance on special occasions—we use ours two or three times a year. But fireplaces burn very inefficiently, and they result in so much airflow up through the chimney that they can actually cause a net loss of energy. Cold air leaks into the house to replace all the room air going up the chimney, and this forces your central heating system to work harder.Burning wood cleanly and efficiently depends on three primary factors: the choice of wood stove; how the wood is stored and managed; and operation of the stove.Choosing a Clean-Burning, Efficient Wood StoveThe starting point in clean, efficient wood stove operation is the selection of the stove. Since July 1, 1990, all new wood stoves sold in the U.S. have been required to carry U.S. Environmental Protection Agency (EPA) certification. (The 1988 law banned the manufacturing of non-EPA-compliant wood stoves after July 1, 1988 and the sale of such stoves two years later.) The EPA standard for non-catalytic wood stoves is 7.5 grams per hour of emissions and for catalytic wood stoves 4.1 grams per hour. By comparison, older, non-certified wood stoves typically produce 40 to 60 grams per hour of pollution, according the EPA.Instituting stringent air pollution standards for wood stoves was a bold and controversial move by the federal government. It put over 80% of wood stove manufacturers out of business because it was too expensive for smaller companies to change their designs. But it also dramatically reduced pollution from wood stoves and boosted combustion efficiency—reducing air pollution by as much as 85%.Manufacturers achieved these improvements by significantly redesigning wood stoves—for example by insulating the firebox, adding baffles that lengthened the smoke path through the stove resulting in more complete combustion, and providing air-inlet holes above the combustion chamber to preheat combustion air. The new-generation, non-catalytic Vermont Castings Defiant NC 1610 and Encore NC 1450 wood stoves are the cleanest-burning models available, with EPA emissions ratings of less than 1 gram per hour, but all new wood stoves are far cleaner than their ancestors from two decades ago.Properly Seasoning FirewoodThe single most important factor for clean, efficient wood burning is using only dry wood. Wood should be seasoned at least six months off the ground and under cover after it is cut and split. Properly seasoned wood is usually deeply checked (checks are end-grain cracks that form as wood dries) and makes a hollow sound when two pieces are knocked together. If the moisture content of wood is high, that water evaporates as the wood is burned, which keeps the combustion temperature low. Even the most advanced wood stove will generate a lot of pollution and burn less efficiently if green (unseasoned) wood is used in it.The six months’ drying of firewood should be considered a minimum. Ideally, several years’ worth of firewood should be kept on hand, with the oldest burned first. One way of organizing this is by stacking green wood outdoors, and then after a season or two moving a heating-season’s worth of wood into a fully covered shed, from which a supply is brought into the house as needed. Green wood should not be stored indoors because of the significant amount of moisture that it will introduce to the house.In splitting firewood, keep the diameter of the split logs relatively small, especially for smaller wood stoves, so that there will be a lot of surface area during combustion. Smaller logs will also dry out more quickly.Operating Wood Stoves EfficientlyTo achieve optimal performance of a wood stove, it should be operated hot. Start the wood stove with crumpled newspaper and kindling. As the fire burns down, rake the coals toward the front or side of the stove, creating a mound (rather than spreading them out), and add several logs at the same time. In milder weather, build smaller fires, but still operate the stove hot, rather than keeping a large fire going and damping it down (restricting the air inlet). Regularly remove ashes so that air flow in the firebox is not impeded and there is plenty of room for wood.Fortunately, there’s an easy way to tell how cleanly (and efficiently) you’re burning your wood stove: the smoke coming out of your chimney. If you generate lots of smoke, the combustion isn’t very complete and a lot of particulate (and other) pollution is being created. This may occur if the wood isn’t very dry, as noted above. A lot of smoke may also indicate that you’re not bringing enough combustion air into your wood stove—most wood stove have an air inlet control. If unsure about proper operation of your wood stove for optimal performance, consult with the company you bought it from or a chimney cleaning service.To minimize pollution, never burn household trash, any manufactured or painted wood (including plywood and particleboard), or pressure-treated wood—burning any of these materials is illegal in Vermont.Also avoid moldy or rotten wood and even driftwood (the salt may corrode the stove and stovepipe or result in toxic emissions).For both safety and efficient operation, have the chimney or stovepipe cleaned at least annually. Build-up of soot can restrict the chimney draft and diminish stove performance. For safety, install smoke and carbon monoxide detectors and make sure they are functioning properly. Replace batteries on battery-powered detectors at least annually, or whenever the low-battery alert sounds.last_img read more


first_imgGetting into drone video production? Here are some tips for getting great footage and some must-know information for new pilots.Love them or hate them, drones are now a big part of video production. Not only do they allow you to quickly capture aerial shots in minutes, they have also become so agile that they can be flown at a low altitude to replicate traditional crane moves.In this post, we will be covering some basics of drone flight: the terms you should be using, no-fly zones, flying for commercial use, and the upcoming FAA drone registration and regulations.Flight TerminologyWhen in flight, you need to know the correct terms to communicate effectively with your crew. This is the same principle as traditional camera movements. You need to know what to do when a shot calls for a pan or tilt.When a drone is in flight, it can move in three dimensions. These axes are lateral, vertical, and longitudinal. Based on the drone’s center of mass, the flight parameters allow the aircraft to move in those three dimensions. In layman’s terms, you can control the drone to move forwards and backwards, up and down, and side to side. 1. YawA yaw changes the direction the drone faces by turning the aircraft to the left and right on the vertical axis.  This is the same as turning your head to the left or right.2. PitchA pitch angles the drone’s nose up or down to move the aircraft forward or backward. This is the equivalent of looking up or down.3. RollA roll angles the drone’s body to the left or fight to move the aircraft side to side. While always looking forward, tilt your head to the left of right. Flying for Commercial Use (in the United States)At the time of writing, it is still illegal to fly a drone for commercial purposes without a license. This includes creating videos for clients. There will be new legislation in the coming months that will allow commercial use after registering your aircraft with the Federal Aviation Administration or FAA. The terms are still not known.Image via Federal Aviation AdministrationHowever, you can still fly your drone and shoot video for hobby purposes, as long as it’s recreational. Your other option is to apply for an FAA Section 333 Exemption which will allow you to fly Unmanned Aircraft Systems, like a drone, for commercial use. These exemptions are issued on a case-by-case basis, so it’s not guaranteed that you will received approval to fly.Every country has their own various flight laws, so be sure you read up before you take flight. No Fly ZonesThe final thing we will cover is the ever-important No-Fly Zone. No-Fly Zones should be taken very seriously, as violating that airspace is a federal matter. There are four main types of No Fly Zones.1. Major AirportsThere is a No-Fly Zone around every major airport and most medium-sized airports. There is a five mile No-Fly Zone radius around an airport.2. U.S. Military BasesThese No-Fly Zones are directly above every military base of any size.3. U.S. National ParksAll National Parks are No-Fly Zones, so don’t even plan on flying over Old Faithful or by Mount Rushmore. Flying in a National Park is a good way to get tazed.4. Temporary Flight Restrictions (TFR)These temporary No-Flight Zones are created for special events, usually with very large crowds. These are issued for sporting events like every NFL and NCAA football game, Major League Baseball games, NASCAR and Indy Car races, as well as any major event that applies for an FAA airspace waiver.Pursuant to 49 USC 40103(b), the Federal Aviation Administration (FAA) classifies the airspace defined in this NOTAM as ‘National Defense Airspace’. Any person who knowingly or willfully violates the rules pertaining to operations in this airspace may be subject to certain criminal penalties under 49 USC 46307. Pilots… may be intercepted, detained and interviewed by law enforcement/security personnel. – Sporting Event Temporary Flight Restriction FDC NOTAM 4/3621If you are planning a flight, I highly recommend Don’t Fly Drones Here. This is a great interactive map that features all No Fly Zones and is constantly updated with Temporary Flight Restrictions, so you will know if there are any places you shouldn’t be.If you are looking to buy your first drone, be sure to check out our definitive drone buying guide.Drone model from TF3DM user ysup12last_img read more


first_imgDon’t miss out on the latest news and information. LATEST STORIES Sports Related Videospowered by AdSparcRead Next Ethel Booba twits Mocha over 2 toilets in one cubicle at SEA Games venue PH underwater hockey team aims to make waves in SEA Games PLAY LIST 02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City01:07Trump talks impeachment while meeting NCAA athletes02:49World-class track facilities installed at NCC for SEA Games02:11Trump awards medals to Jon Voight, Alison Krauss MOST READ “This is a golden opportunity for us to make it back to the semis. We will definitely not waste it,” said Generika coach Sherwin Meneses. “I told the girls to just maintain what they are doing. If they can double the effort they showed in Game 1, that would be great.”Generika-Ayala will again rely on Kseniya Kocyigit of Azerbaijan and Kanjana Kuthaisong of Thailand in its semifinal bid. —MARC REYESFEATURED STORIESSPORTSPrivate companies step in to help SEA Games hostingSPORTSPalace wants Cayetano’s PHISGOC Foundation probed over corruption chargesSPORTSSingapore latest to raise issue on SEA Games food, logistics SEA Games hosting troubles anger Duterte DA eyes importing ‘galunggong’ anew Cayetano: Senate, Drilon to be blamed for SEA Games mess Philippine Arena Interchange inaugurated Private companies step in to help SEA Games hosting The long, long road to Boston Photo by Tristan Tamayo/INQUIRER.netGenerika-Ayala and PLDT Home Fibr clash once again on Saturday for the fourth and last semifinals slot in the Philippine Superliga Grand Prix at FilOil Flying V Centre in San Juan.The Lifesavers erased the Power Hitters’ twice-to-beat luxury with a 25-22, 25-27, 25-21, 25-19 victory last Thursday.ADVERTISEMENT Panelo: Duterte ‘angry’ with SEA Games hosting hassles Hontiveros presses for security audit of national power grid View commentslast_img read more