Grub

November 3, 2011 by · Leave a Comment 

tufail

Grub, in entomology, familiar term for the larval stage of certain beetles. Most specifically, the term is used for larvae with soft, thick bodies, well-developed heads, and legs on the thorax but not on the abdomen. In general, grubs tend to be pale in color. They are usually slow-moving and many are soil dwellers. Similar larvae of many other insects are also called grubs.

Last year, European Chafer grub feeding resulted in significant damage to lawns in many service areas. It is probably the most serious grub pest of home lawns. With the reports that are coming in, the potential for damage to turf in local counties is high. European Chafer is native to western and central Europe and was discovered on the East Coast in 1940, and has since spread from there.

Around the middle of June to early July adult European Chafers emerge from the soil for their brief mating flights. The adult looks similar to a June beetle. They are about ½ inch-long and light brown. Around dusk thousands of adults swarm around trees or large shrubs. They do not feed, but the mating swarms are quite spectacular. They fly for about half an hour and mate. The female then enters the soil to lay her eggs.

The eggs are deposited two to four inches below the soil surface. Eggs hatch in early August and the grubs begin to feed on grass roots which continues onto November. The grubs are typically C-shaped white grubs that reach a maximum size of one inch long and 1/4 inch wide. These grubs look similar to other white grubs, i.e., May or June Beetle and Japanese Beetle. Those grubs that survived the winter, which most do, resume feeding in April and will continue through early June. When grub populations are high enough (10 grubs per square foot) significant root damage will occur. As a result, large patches of turf will die and turn brown, which will be quite visible by next spring. With the grass roots eaten, a homeowner will be able to lift up large sections of turf where the grubs should be visible. Because European Chafer is an import, there are no predators, parasites or diseases that help keep this insect in control. European Chafer is found more in dry soils, so irrigated laws may not have a significant problem. Homeowners with fall or spring turf damage, or who see the mating swarms in their neighborhoods, may want to consider using an insecticide to control white grubs. There are safe effective pesticides, that when used at the correct time of the year, will control grub populations, preventing significant turf damage.

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Hearing Aids

June 16, 2011 by · Leave a Comment 

tufailA hearing aid is a small electronic device that you wear in or behind your ear. It makes some sounds louder so that a person with hearing loss can listen, communicate, and participate more fully in daily activities. A hearing aid can help people hear more in both quiet and noisy situations. However, only about one out of five people who would benefit from a hearing aid actually uses one.

A hearing aid has three basic parts: a microphone, amplifier, and speaker. The hearing aid receives sound through a microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them to the ear through a speaker.

Hearing aids are primarily useful in improving the hearing and speech comprehension of people who have hearing loss that results from damage to the small sensory cells in the inner ear, called hair cells. This type of hearing loss is called sensorineural hearing loss. The damage can occur as a result of disease, aging, or injury from noise or certain medicines.

A hearing aid magnifies sound vibrations entering the ear. Surviving hair cells detect the larger vibrations and convert them into neural signals that are passed along to the brain. The greater the damage to a person’s hair cells, the more severe the hearing loss, and the greater the hearing aid amplification needed to make up the difference. However, there are practical limits to the amount of amplification a hearing aid can provide. In addition, if the inner ear is too damaged, even large vibrations will not be converted into neural signals. In this situation, a hearing aid would be ineffective.

If you think you might have hearing loss and could benefit from a hearing aid, visit your physician, who may refer you to an otolaryngologist or audiologist. An otolaryngologist is a physician who specializes in ear, nose, and throat disorders and will investigate the cause of the hearing loss. An audiologist is a hearing health professional who identifies and measures hearing loss and will perform a hearing test to assess the type and degree of loss.

The hearing aid that will work best for you depends on the kind and severity of your hearing loss. If you have a hearing loss in both of your ears, two hearing aids are generally recommended because two aids provide a more natural signal to the brain. Hearing in both ears also will help you understand speech and locate where the sound is coming from.

You and your audiologist should select a hearing aid that best suits your needs and lifestyle. Price is also a key consideration because hearing aids range from hundreds to several thousand dollars. Similar to other equipment purchases, style and features affect cost. However, don’t use price alone to determine the best hearing aid for you. Just because one hearing aid is more expensive than another does not necessarily mean that it will better suit your needs.

A hearing aid will not restore your normal hearing. With practice, however, a hearing aid will increase your awareness of sounds and their sources. You will want to wear your hearing aid regularly, so select one that is convenient and easy for you to use. Other features to consider include parts or services covered by the warranty, estimated schedule and costs for maintenance and repair, options and upgrade opportunities, and the hearing aid company’s reputation for quality and customer service.

Hearing aids take time and patience to use successfully. Wearing your aids regularly will help you adjust to them.

Become familiar with your hearing aid’s features. With your audiologist present, practice putting in and taking out the aid, cleaning it, identifying right and left aids, and replacing the batteries. Ask how to test it in listening environments where you have problems with hearing. Learn to adjust the aid’s volume and to program it for sounds that are too loud or too soft. Work with your audiologist until you are comfortable and satisfied.

Although they work differently than the hearing aids described above, implantable hearing aids are designed to help increase the transmission of sound vibrations entering the inner ear. A middle ear implant (MEI) is a small device attached to one of the bones of the middle ear. Rather than amplifying the sound traveling to the eardrum, an MEI moves these bones directly. Both techniques have the net result of strengthening sound vibrations entering the inner ear so that they can be detected by individuals with sensorineural hearing loss.

A bone-anchored hearing aid (BAHA) is a small device that attaches to the bone behind the ear. The device transmits sound vibrations directly to the inner ear through the skull, bypassing the middle ear. BAHAs are generally used by individuals with middle ear problems or deafness in one ear. Because surgery is required to implant either of these devices, many hearing specialists feel that the benefits may not outweigh the risks.

Hearing aids are generally not covered by health insurance companies, although some do. For eligible children and young adults ages 21 and under, Medicaid will pay for the diagnosis and treatment of hearing loss, including hearing aids, under the Early and Periodic Screening, Diagnostic, and Treatment (EPSDT) service. Also, children may be covered by their state’s early intervention program or State Children’s Health Insurance Program (SCHIP).

Medicare does not cover hearing aids for adults; however, diagnostic evaluations are covered if they are ordered by a physician for the purpose of assisting the physician in developing a treatment plan. Since Medicare has declared the BAHA a prosthetic device and not a hearing aid, Medicare will cover the BAHA if other coverage policies are met.

Some nonprofit organizations provide financial assistance for hearing aids, while others may help provide used or refurbished aids. Contact the National Institute on Deafness and Other Communication Disorders’ (NIDCD’s) Information Clearinghouse with questions about organizations that offer financial assistance for hearing aids.

Researchers are looking at ways to apply new signal processing strategies to the design of hearing aids. Signal processing is the method used to modify normal sound waves into amplified sound that is the best possible match to the remaining hearing for a hearing aid user. NIDCD-funded researchers also are studying how hearing aids can enhance speech signals to improve understanding.

In addition, researchers are investigating the use of computer-aided technology to design and manufacture better hearing aids. Researchers also are seeking ways to improve sound transmission and to reduce noise interference, feedback, and the occlusion effect. Additional studies focus on the best ways to select and fit hearing aids in children and other groups whose hearing ability is hard to test.

Another promising research focus is to use lessons learned from animal models to design better microphones for hearing aids. NIDCD-supported scientists are studying the tiny fly Ormia ochraceabecause its ear structure allows the fly to determine the source of a sound easily. Scientists are using the fly’s ear structure as a model for designing miniature directional microphones for hearing aids. These microphones amplify the sound coming from a particular direction (usually the direction a person is facing), but not the sounds that arrive from other directions. Directional microphones hold great promise for making it easier for people to hear a single conversation, even when surrounded by other noises and voices.

Hearing aid electronics control how sound is transferred from the environment to your inner ear. All hearing aids amplify sounds, making them louder so that you can hear them better. Most hearing aid manufacturers now only produce digital hearing aids — analog hearing aids are being phased out.

With digital technology, a computer chip converts the incoming sound into digital code, then analyzes and adjusts the sound based on your hearing loss, listening needs and the level of the sounds around you. The signals are then converted back into sound waves and delivered to your ears. The result is sound that’s more finely tuned to your hearing loss. Digital hearing aids are available in all styles and price ranges.

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Amnesia

November 5, 2009 by · Leave a Comment 

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Amnesia refers to the loss of memory. Memory loss may result from two-sided (bilateral) damage to parts ofthe brain vital for memory storage, processing, or recall (the limbic system, including the hippocampus in the medial temporal lobe).

Amnesia can be a symptom of several neurodegenerative diseases; however, people whose primary symptom is memory loss (amnesiacs), typically remain lucid and retain their sense of self. They may even be aware that they suffer from a memory disorder.

People who experience amnesia have been instrumental in helping brain researchers determine how the brain processes memory. Until the early 1970s, researchers viewed memory as a single entity. Memory of new experiences, motor skills, past events, and previous conditioning were grouped together in one system that relied on a specific area of the brain.

If all memory were stored in the same way, it would be reasonable to deduce that damage to the specific brain area would cause complete memory loss. However, studies of amnesiacs counter that theory. Such research demonstrates that the brain has multiple systems for processing, storing, and drawing on memory.

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Concussion

June 27, 2009 by · Leave a Comment 

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Concussion is a trauma-induced change in mental status, with confusion and amnesia, and with or without a brief loss of consciousness.

A concussion occurs when the head hits or is hit by an object, or when the brain is jarred against the skull, with sufficient force to cause temporary loss of function in the higher centers of the brain. The injured person may remain conscious or lose consciousness briefly, and is disoriented for some minutes after the blow. According to the Centers for Disease Control and Prevention, approximately 300,000 people have mild to moderate sports-related brain injuries each year, most of them young men between 16 and 25.

While concussion usually resolves on its own without lasting effect, it can set the stage for a much more serious condition. “Second impact syndrome” occurs when a person with a concussion, even a very mild one, suffers a second blow before fully recovering from the first. The brain swelling and increased intracranial pressure that can result is potentially fatal. More than 20 such cases have been reported since the syndrome was first described in 1984.

A state following injury in which there is temporary functional impairment without physical evidence of damage to the impaired tissues. The term usually refers to cerebral concussion produced by any type of trauma.

From a clinical point of view cerebral concussion is produced by a head injury which causes temporary unconsciousness but with complete recovery within 24 h. This temporary alteration is believed to result from one of several mechanisms. In all of these a sudden acceleration or deceleration appears to be aprerequisite. The sudden movement is thought to cause an unequal shifting of tissues of different specific gravities within the skull, between skull and brain, or between different brain tissues.

This word originally meant severe shaking, or the shock of an impact, but has come to mean the effect of such violence on the brain. The immediate effect of such an impact — usually when the moving head meets an immovable object, most commonly the ground — is unconsciousness. After a mild injury this lasts only a minute or so and the person is then dazed or confused for a few more minutes before recovering normal consciousness; occasionally recovery may take hours. After more severe impact injury, the patient may remain in coma for many days and remain confused for many more days thereafter. In either event there will be no memory for the moment of impact, often for a period immediately before this, and always for the period of unconsciousness and confusion: this is known as post-traumatic amnesia.

It is now recognized that the effect of the jelly-like brain being distorted by these forces is to stretch or even tear delicate nerve fibres, resulting in some permanent damage. After mild injury this is very limited, but after more severe impact there is more severe and more widespread damage to fibres. There can therefore be both mild and severe concussion.

After only mild concussion there are often symptoms for several days, sometimes weeks — headache, fatigue, dizziness, and poor concentration. In a few patients these post-concussional symptoms give rise to anxiety and other psychological symptoms that can aggravate and prolong the organically-impaired function that the patient suffers. In contact sports there is the risk of repeated concussions, and the small amount of damage sustained each time can be cumulative. Moreover, soon after one concussion the brain may be more susceptible to a second blow, and this is why most sports have rules about waiting 2-3 weeks before playing again, for example after concussion on the football field or in the boxing ring. The repeated concussions over a period of years that boxers can experience may result in progressive brain damage, evident in altered mental function and control of the limbs — the so-called ‘punch-drunk’ syndrome. This is now rare, as there are stringent regulations to limit exposure to such a hazard.

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