 This is around one thousandth of the size of an individual electron and 100 times more precise than previously demonstrated. For context, the measurement of such small changes in the laser wavelength is the equivalent to measuring the length of a football pitch with an accuracy equivalent to the size of one atom.
Wavemeters are used in many areas of science to identify the wavelength of light. All atoms and molecules absorb light at very precise laser wavelengths, so the ability to identify and manipulate wavelength at high resolution is important in diverse fields ranging from cooling of individual atoms to temperatures colder than the depths of outer space, to the identification of biological and chemical samples. The ability to distinguish between different wavelengths of light also allows more information to be sent through fiber-optic communications networks by encoding different data channels with different wavelengths.
Conventional wavemeters analyse changes in wavelength using delicate, high-precision optical components. The cheapest instruments used in most everyday research cost tens of thousands of pounds. In contrast, the St Andrews wavemeter consists of only a 20cm length of optical fiber and a camera. In future it may be made even smaller.
Dr Kishan Dholakia explained: “The principle of the wavemeter can be easily demonstrated at home. If you shine a laser pointer on a rough surface like a painted wall, or through a semi-transparent material like frosted sellotape, the laser gets scrambled into the grainy speckle pattern. If you move the laser, or change any of its properties, the exact pattern you see will change dramatically. It’s this sensitivity to change that makes speckle a good choice for measuring wavelength.”
Dr Graham Bruce, also from the School of Physics and Astronomy and lead author on the paper, said: “There is major investment both in the UK and around the world at present in the development of a new generation of optical and quantum technologies, which promise to revolutionise the way we measure the world around us, the ways we communicate and the way we secure our digital information. Lasers and the way we measure and control their properties are central to this development, and we believe that our approach to measuring wavelength will have an important role to play.”
In future, the team hopes to demonstrate the use of quantum technology applications in space and on Earth, as well as to measure light scattering for biomedical studies in a new, inexpensive way.
The paper Overcoming the speckle correlation limit to achieve a fiber wavemeter with attometer resolution is published in Optics Letters and is available online.Maine Agricultural & Forest Experiment Station Electronic Publications All publications from the Maine Agricultural and Forest Experiment Station (MAFES) that are available in an electronic format. Most of these publications are available as pdf files. This is not a complete listing of all official publications. To see a list of other MAFES publications in print, visit the Maine Agricultural & Forest Experiment Station Publications page at https://umaine.edu/mafes/publications/.As a pediatrician, I am frequently seeing kids who come in with a variety of complaints “just to make sure they don’t have an ear infection”. They may be waking at night, pulling on their ears, coughing, having a fever or actually complaining of ear pain. Ear pain is one of the most common concerns that parents have. The good news is that the vast majority of the time, kids and babies who are pulling on their ears but who are not otherwise sick, do not have an infection. Even those with a common cold do not always end up with an ear infection. But when kids do get an ear infection, what does that mean and what should parents do? It’s time to talk all things ear infections with our resident Ear, Nose and Throat doctor, Dr. Matthew Brigger.
Dr. Brigger explains that “ear infections occur when bacteria grow behind the ear drum leading to a collection of pus” which is thick fluid created by the immune system while fighting the infection. The inflammation and pus accumulation causes “pressure [on the ear drum], pain and temporary hearing loss”. Not all red ears are infections that require intervention though. It is possible to have a viral ear infection (inflammation and pain of the ear drum) or to have clear fluid behind the ear drum, both of which can happen during a cold. A bacterial ear infection is diagnosed when the doctor sees pus causing a bulge of the ear drum, especially in a child with signs of inflammation like pain and fever.
How do kids get ear infections?
We most often see ear infections in kids who are already sick with colds. There is actually a very good reason for that! Dr. Brigger describes it this way: “The space behind the ear drum, also known as the middle ear, is filled with air which comes from the nose through a small internal connection known as the Eustachian tube. By having air in the middle ear, our eardrum can vibrate properly.” That’s how we hear. During a cold (or allergies), congestion closes off the Eustachian tube. “When the Eustachian tube closes off, the ear can fill with fluid which then becomes infected. Due to the small size and immature nature of the Eustachian tube in children, they are more likely to get ear infections than adults.” Some kids have dysfunction of their Eustachian tubes which causes increased pressure in the middle ear even when they aren’t sick with a cold. That can also lead to an infection.
Our treatment of ear infections has evolved tremendously. “Most ear infections are relatively minor” says Dr. Brigger “and some do not even require antibiotics.” Our current guidelines allow for pain control for 24-48 hours prior to starting antibiotics in children over 2 years of age, who do not have a history of ear problems and who are otherwise well. “In general, antibiotics will lead to resolution of the acute infection relatively quickly” once they are started and as long as the correct antibiotic is used. It can be normal for fluid to persist in the middle ear after an infection or be present during a cold, but this is “non infected ear fluid which may remain [behind the ear drum] up to several months”. Non infected fluid in the middle ear does not require antibiotics.
What are complications of ear infections?
While most ear infections are benign and will resolve on their own, some ear infections can result in complications. “Untreated ear infections can lead to rupture and scarring of the ear drum. Occasionally, repeated ear infections can lead to permanent hearing loss. In rare instances, ear infections can lead to more serious bacterial infections, including infection of the skull bones or the brain. Rarely ear infections can cause damage to the nerve that controls facial movement.” Therefore, if your child is still having pain or physical signs of an ear infection 24-48 hours after diagnosis, go ahead and give them the antibiotics prescribed.
So, in a nutshell, if you are worried about your child’s ears, have him/her checked. Follow your doctor’s advice and if antibiotics are prescribed, finish the entire prescription. If your child is getting frequent ear infections, a referral to the Ear, Nose and Throat doctor may be needed.
All quotes are attributed to Dr. Matthew Brigger, Otolaryngologist at Rady Children’s Hospital in San Diego. His bio can be found in our mutual post on Swimmer’s Ear here.
Now that homestead construction has been underway for more than a year we have created a revised site plan that reflects our current vision. Our quest for sustainability seems more important than ever and I think that shows in our new homestead map.
After bringing chickens and rabbits onto our farm, we decided to create space for keeping milk goats and pigs. We've doubled our garden space and have begun experimenting with growing grains. Our plans may seem ambitious, but they take into account the agricultural space that we believe is needed to achieve a truly sustainable balance. With careful planning we think we will be able to meet many of our needs on our 2.25 acres. However we do hope to acquire a few more acres of land to provide adequate space for hay production and pasture.
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