Wikisnaps! We find what's interesting on Wikipedia, so you don't have to!

The Bell AH-1 SuperCobra is a twin-engine attack helicopter based on the US Army's AH-1 Cobra. The twin Cobra family includes the AH-1J SeaCobra, the AH-1T Improved SeaCobra, and the AH-1W SuperCobra. The AH-1W is the backbone of the United States Marine Corps's attack helicopter fleet, but will be replaced in service by the AH-1Z Viper upgrade in the next decade. The AH-1 Cobra was developed in the mid-1960s as an interim gunship for the U.S. Army for use in Vietnam. The Cobra shared the proven transmission, rotor system, and the T53 turboshaft engine of the UH-1 "Huey". By June 1967, the first AH-1G HueyCobras had been delivered. Bell built 1,116 AH-1Gs for the U.S. Army between 1967 and 1973, and the Cobras chalked up over a million operational hours in Vietnam. The U.S. Marine Corps was very interested in the AH-1G Cobra, but preferred a twin-engined version for improved safety in over-water operations, and also wanted a more potent turret-mounted weapon. At first, the Department of Defense had balked at providing the Marines with a twin-engined version of the Cobra, in the belief that commonality with Army AH-1Gs outweighed the advantages of a different engine fit. However, the Marines won out and awarded Bell a contract for 49 twin-engined AH-1J SeaCobras in May 1968. As an interim measure, the U.S. Army passed on 38 AH-1Gs to the Marines in 1969. The AH-1J also received a more powerful gun turret. It featured a three barrel 20 mm XM197 cannon that was based on the six barrel M61 Vulcan cannon. Marine Cobras provided support for the US humanitarian intervention in Somalia, during Operation Restore Hope in 1992-1993. They were also employed during the US invasion of Haiti in 1994. USMC Cobras were used in US military interventions in the former Yugoslavia in the 1990s, and assisted in the rescue of USAF Captain Scott O'Grady, after his F-16 was shot down by a SAM in June 1995. AH-1 Cobras continue to operate with the U.S. Marine Corps. USMC Cobras were also used in operations throughout the 1990s. USMC Cobras have also served in Operation Enduring Freedom in Afghanistan and in Operation Iraqi Freedom in the ongoing conflict in Iraq. While new replacement aircraft were considered as an alternative to major upgrades of the AH-1 fleet, Marine Corps studies showed that an upgrade was the most affordable, most supportable and most effective solution for the Marine Corps light attack helicopter mission. [READ THE REST OF THIS ARTICLE]





Derweze is a Turkmenistan village of about 350 inhabitants, located in the middle of the Karakum desert, about 260 km north from Ashgabat. Darvaza inhabitants are mostly Turkmen of the Teke tribe, preserving a half-nomadic lifestyle. The Derweze area is rich in natural gas. While drilling in 1971 geologists accidentally found an underground cavern filled with natural gas. The ground beneath the drilling rig collapsed, leaving a large hole with a diameter of about 50100 meters (The Door to Hell). To avoid poisonous gas discharge, it was decided to burn the gas. Geologists had hoped the fire would go out in a few days but it has been burning ever since. Locals have named the cavern The Door to Hell. Next to capturing the gas, flaring is safer and friendlier to the environment than releasing the methane into the atmosphere as methane is a relatively potent greenhouse gas with a high global warming potential of 72 (averaged over 20 years) or 25 (averaged over 100 years). Turkmenistan plans to increase its production of natural gas. In April 2010, the President of Turkmenistan Gurbanguly Berdimuhamedow visited the site and ordered that the hole should be closed, or other measures be taken to limit its influence on the development of other natural gas fields in the area [READ THE REST OF THIS ARTICLE]



Australian funnel-web spiders are very venomous spiders of the family Hexathelidae, represented by an estimated 40 species of Hadronyche and the sole species of the genus Atrax. A. robustus, the notoriously dangerous Sydney funnel-web spider. Funnel-webs are one of the three most dangerous spiders in the world and are regarded by some to be the most dangerous. Examination of bite records has implicated wandering males in most if not all fatal bites to humans. Adult males, recognized by the modified terminal segment of the palp, will defend themselves vigorously if they feel threatened and tend to wander during the warmer months of the year looking for receptive females for mating. They are attracted to water and hence are often found in swimming pools where they have fallen while wandering. The spiders can survive such immersion for several hours and can deliver a bite when removed from the water. They also show up in garages and yards in suburban Sydney. Contrary to a commonly held belief, no funnel-web spider is able to jump, although they can run quickly. Although extremely toxic to primates, the venom appears to be fairly harmless to many other animals. It has been suggested that these animals may be resistant to the venom's effects due to the presence of IgG, and possibly cross-linked IgG and IgM inactivating factors in their blood plasma that bind to the toxins responsible and neutralise them, or it may involve a non-specific reaction due to the highly basic nature of the toxins. The female venom was thought to be only about a sixth as potent to humans as that of the male but recent research has proven that false. The bite of a female or juvenile may be serious; however, considerable variability occurs in venom toxicity between species, together with assumable degrees of inefficiency in the method of venom delivery. [READ THE REST OF THIS ARTICLE]





Knee replacement, or knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve the pain and disability of osteoarthritis. It may be performed for other knee diseases such as rheumatoid arthritis and psoriatic arthritis. In patients with severe deformity from advanced rheumatoid arthritis, trauma, or long standing osteoarthritis, the surgery may be more complicated and carry higher risk. Osteoporosis does not typically cause knee pain, deformity, or inflammation and is not a reason to perform knee replacement. Other major causes of debilitating pain include meniscus tears, cartilage defects, and ligament tears. Debilitating pain from osteoarthritis is much more common in the elderly. Knee replacement surgery can be performed as a partial or a total knee replacement. In general, the surgery consists of replacing the diseased or damaged joint surfaces of the knee with metal and plastic components shaped to allow continued motion of the knee. The operation involves substantial postoperative pain, and includes vigorous physical rehabilitation. The recovery period may be 6 weeks or longer and may involve the use of mobility aids (e.g. walking frames, canes, crutches) to enable the patient's return to preoperative mobility. Knee replacement surgery is most commonly performed in people with advanced osteoarthritis. It should be considered when conservative treatments have been exhausted. Physical therapy has been shown to improve function and may delay or prevent the need for knee replacement. Knee Arthroplasty is major surgery. Before the surgery is performed, pre-operative tests are done: usually a complete blood count, electrolytes, APTT and PT to measure blood clotting, chest X-rays, ECG, and blood cross-matching for possible transfusion. About a month before the surgery, the patient may be prescribed supplemental iron to boost the hemoglobin in their blood system. Accurate X-rays of the affected knee are needed to measure the size of components which will be needed. Medications such as warfarin and aspirin will be stopped some days before surgery to reduce the amount of bleeding. Patients may be admitted on the day of surgery if the pre-op work-up is done in the pre-anesthetic clinic or may come into hospital one or more days before surgery. Some hospitals offer a pre-operative seminar for this surgery. With the advent of Medical Tourism, a lot of people from the US and UK have started to travel to India for undergoing knee replacements. This phenomenon is primarily due to the significant reduction in the operating cost. For instance, a knee replacement that ranges around $40,000, can be successfully accomplished in $6,200 - $8,500 in a top class Indian hospital. [READ THE REST OF THIS ARTICLE]



wikisnap.com is not affiliated with or endorsed by wikipedia. wikipedia and the wikipedia globe are registered trademarks of wikipedia.org.
article content reproduced in compliance with wikipedia's copyright policy and gnu free documentation license
view our privacy policy and terms of service here