Monthly Archives: July 2013
Sprites are a fleeting, ethereal and a relatively unknown aspect of lightning storms.
Since the 1960s, and probably before then, pilots have been seeing but seldom reporting what have become known as sprites and elves above the clouds. Sprites are electrically-charged lightning funnels which shoot up from the top of a cloud as much as 60 miles into the atmosphere. These charges are vivid red and usually occur in clusters of three or more but are only visible for nanoseconds. They are sometimes preceded by lower altitude red flashes known as elves, and can have striking blue tendrils which are easily mistaken for blue jets. While they are a similar visual phenomenon, blue jets are less powerful than the sprites and travel neither as quickly nor as far.
Because ‘everyone knows’ lightning goes to ground, pilots were naturally reluctant to report this phenomenon in case they found themselves grounded for hallucinating. As a result, serious research was delayed until the last 15 years or so.
While sprites are more common during positively-charged lightning storms, this is not due to any preference on the part of the sprite, but rather due to the greater internal energy of a positively charged storm. It was not until 1999 that the first sprites of a negatively-charged storm were recorded.
During a powerful storm it is possible to see red sprites, elves and blue jets, but the exact atmospheric conditions which create such a show are uncertain.
As sprites are relatively new to the science world there is still a lot more to learn about them.
It is only with the advent of high speed photography that the existence of these light shows could be confirmed, and even with that they were first photographed by accident in 1989. Amazingly, there have since been more than 10,000 confirmed sightings. They are also known to create a very low-frequency thunder which was only recently captured with the use of specialist listening equipment.
As their energy is spread more thinly than the traditional thunderbolt due to the cone like dispersal from cloud to atmosphere, they are thought to be relatively weak. Sprites are cold plasma phenomena that lack the hot channel temperatures of tropospheric lightning, so they are more akin to fluorescent tube discharges than to lightning discharges.
The effects of sprites are currently being investigated by various agencies including NASA who seriously addressed them as a possible cause for the tragic loss of the space shuttle Columbia, which was, incidentally, on a mission to record data about the very same sprite phenomenon.
The link below shows footage from the ISS and shows a red sprite over East Asia at around 0:06.
Sprites are sometimes preceded, by about 1 millisecond, by a sprite halo, a pancake-shaped region of weak, transient optical emissions approximately 50 kilometres (31 mi) across and 10 kilometres (6.2 mi) thick. The halo is centred at about 70 kilometres (43 mi) altitude above the initiating lightning strike. These halos are thought to be produced by the same physical process that produces sprites, but for which the ionization is too weak to cross the threshold required for streamer formation.
Recent research carried out at the University of Houston in 2002 indicates that some normal (negative) lightning discharges produce a sprite halo, and that every lightning bolt between cloud and ground attempts to produce a sprite or a sprite halo.
The Dandelion is known by it’s latin name of Taraxacum officinale. There are a number of similar plants labelled false dandelions but we’ll look at the one we all know.
They are native to Eurasia and North and South America, and two species, T. officinale and T. erythrospermum, are found as weeds worldwide. Both species are edible in their entirety. The common name dandelion comes from the French dent-de-lion, meaning “lion’s tooth”. They have very small flowers collected together into a composite flower head. Each single flower in a head is called a floret. Many Taraxacum species produce seeds asexually by apomixis, where the seeds are produced without pollination, resulting in offspring that are genetically identical to the parent plant
Dandelions are tap rooted biennials or perennial plants.The tap root on a dandelion can reach up to a foot and a half in length. This is why they are so hard to remove. If some root is left behind after pulling them up they will regrow.
A Beneficial Weed
The dandelion plant can be a beneficial weed, with a wide range of uses, and is even a good companion plant for gardening. Its taproot will bring up nutrients for shallower-rooting plants, and add minerals and nitrogen to soil. It is also known to attract pollinating insects. Taraxacum seeds are also an important food source for certain birds
As a noxious weed
The Dandelion is considered to be a nuisance in residential and recreational lawns. It is also an important weed in agriculture and causes significant economic damage because of its infestation in many crops worldwide.
However Dandelion has many medicinal uses.
Historically, dandelion was prized for a variety of medicinal properties, and it contains a wide number of pharmacologically active compounds. Dandelion is used as a herbal remedy in Europe, North America and China. It has been used in herbal medicine to treat infections, bile and liver problems, and as a diuretic.
The Dandelion is actually full of full of vitamins A, B, C, and D, as well as minerals such as iron, potassium, and zinc. Dandelion leaves are used to add flavour to salads, sandwiches, and teas. The roots are used in some coffee substitutes, and the flowers are used to make wines!
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A white coat or laboratory coat is a knee-length overcoat worn by professionals in the medical field or by those involved in laboratory work. The coat protects their everyday clothes and also serves as a simple uniform. The garment is made from white or light-coloured cotton, or cotton polyester blend, allowing it to be washed at high temperature and make it easy to see if it is clean.
When used in the laboratory, they protect against accidental spills, e.g. acids. In this case they usually have long sleeves and are made of an absorbent material, such as cotton, so that the user can be protected from the chemical. Some lab coats have buttons at the end of the sleeves, to secure them around the wrist so that they do not hang into beakers of chemicals.
For added safety, a variant of the lab coat, called a “Howie” style lab coat is often adopted . It is called that after a 1978 report commissioned by the UK department of Health and Social Security to codify standard clinical laboratory practices, chaired by a JW Howie. Among the codified standards was protective clothing – the type of wrap around full-coverage lab coat which had been in use in the UK for over a hundred years was nicknamed the “Howie-Style” coat to indicate its compliance with the provisions of this report. It has the buttons on the left flank, elasticated wrists and a mandarin collar and is quite similar to a chef’s uniform and designed to minimise pathogen contact with street clothes.
Do wear a lab coat when a Personal Protective Equipment (PPE) Hazard Assessment of the laboratory determines hazards to the body are present or likely to be present. A good rule of thumb is to wear a lab coat at all times when working in a lab.
Do wear lab coats that cover the knees and have full length sleeves.
Do keep lab coats completely buttoned up. Snap closures are preferred over buttons or zippers to keep the body covered and allow quick removal in an emergency
Do immediately remove a lab coat if on fire or if there is obvious hazardous contamination
Do consider the addition of a rubber apron when there is a significant chance of exposure to corrosive materials
Do keep lab coats clean. If they become contaminated they should be decontaminated or cleaned on site, sent away for cleaning by professionals who have been informed of the hazards or disposed of as a hazardous material.
Don’t wear lab coats unbuttoned as that can compromise a wearers safety
- If the chemical is safe to dispose to drains (e.g. most Acids and Alkalis), rinse it clean in water before sending it to be laundered.
- If the spill was a solvent it must have completely evaporated off before it is cleaned.
- Toxic chemicals spilt on a lab coat will require that it be disposed of via chemical waste.
P&R Labpak Limited offer a range of laboratory coats and currently have some on special offer. Terms and conditions apply.
Please visit http://www.prlabs.co.uk/news/article.php?Id=195 for details.
This trait was critical to the survival and success of our ancestors, aiding their hunting and protective skills, according to National Science Foundation- (NSF) funded research featured on the cover of this week’s journal Nature.
Harvard University researchers supported by NSF’s Biological Anthropology Program discovered that humans are able to throw projectiles at incredible speeds by storing and releasing energy in the tendons and ligaments crossing the shoulder. This energy is used to catapult the arm forward, creating the fastest motion the human body can produce and resulting in very rapid throws.
“Our research demonstrates that the ability to store energy in the shoulder is made possible by three critical changes in our upper bodies that occurred during human evolution,” said Neil Roach, lead researcher currently at the Centre for the Advanced Study of Hominid Paleobiology at The George Washington University. “The expansion of the waist, a lower positioning of the shoulders on the torso, and the twisting of the humerus (the bone in the upper arm) are the key morphological changes that first appeared together nearly two million years ago in the species Homo erectus.”
Two million years ago is also the time at which the archaeological record suggests that our hominin ancestors began to hunt more intensely. “We think that throwing was probably most important early on in terms of hunting behaviour, enabling our ancestors to effectively and safely kill big game,” said Roach. “Eating more calorie-rich meat and fat would have allowed our ancestors to grow larger brains and bodies and expand into new regions of the world—all of which helped make us who we are today.”
To discover how and why humans throw so well, Roach and his team used a 3-D motion-capture camera system–similar to those used to make video games and animate movie characters–to record the throws of collegiate baseball players. They analysed these data using simple physics that breaks down complex movements into the individual motions occurring at each joint and determined velocity and estimated the forces needed to create each motion.
The authors found that humans are able to throw with such velocity by storing elastic energy in their shoulders. This energy storage occurs in the “cocking” phase of the throw, when the arm is pulled backward away from the target.
“The cocking of the arm stretches the tendons, ligaments and muscles crossing the shoulder and stores elastic energy, like a slingshot,” said Roach. “When this energy is then released, it powers the very rapid rotation of the upper arm, which is the fastest motion the human body produces. This rapid rotation also causes the elbow to quickly straighten and the projectile to be released at very high speeds.”
The team also used therapeutic braces to limit the throwers’ movements. “The braces allowed us to mimic our ancestral anatomy in modern throwers, giving us the opportunity to see how anatomical changes that occurred during our evolutionary past would have affected our ability to throw,” said Roach.
Roach’s study is the first to suggest a link between human’s incredible throwing ability and the critical evolutionary shifts made possible by our ancestors’ increased hunting. It is also the first to demonstrate the use of elastic energy in the human arm. Next, Roach and his colleagues plan to build on their work by determining what type of objects our ancestors actually threw.
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Krypton-83 has application in magnetic resonance imaging (MRI) for imaging airways. Much more useful than the ill effects of Kryptonite!
Everyone wants to be greener and help the environment but it’s not always easy. There is a trend to buy more economical products for the laboratory. We use less energy overall remembering to turn lights and equipment off. But what else can we do?
Now you can help just by buying VWR Collection products that you may well buy anyway! And if you don’t why not give them a try?
If you buy £1000 of VWR Collection products then VWR will have 10 trees planted in your name and match that donation. You’ll also get a certificate of your contribution to global reforestation!
Read the flyer on our webpage for more information on what to do. Visit http://www.prlabs.co.uk/news/article.php?Id=194
Let’s see how many trees we can plant!
Terms and geographical limitations apply to this particular offer.