Before Fresnel developed this lens, lighthouses used mirrors to reflect light out to sea. The most effective lighthouses could only be seen eight to twelve miles away. After his invention, the brightest lighthouses could be seen all the way to the horizon, about twenty-four miles.

The Fresnel lens intensifies the light by bending (or refracting) and magnifying the source light through crystal prisms into concentrated beams. The Point Reyes lens is divided into twenty-four vertical panels, which direct the light into twenty-four individual beams. A counterweight and gears similar to those in a grandfather clock rotate the 6000-pound lens at a constant speed, one revolution every two minutes. This rotation makes the beams sweep over the ocean surface like the spokes of a wagon wheel, and creates the Point Reyes signature pattern of one flash every five seconds.

Adult lady beetles and their larvae are an excellent, non-chemical way to control aphids, Colorado potato beetles (egg stage) and other insect pests in your garden  Lady beetles, ladybugs, or ladybird beetles are among the most visible and best known beneficial predatory insects. Over 450 species are found in North America. Some are native and some have been introduced from other countries.

Most lady beetles in North America are beneficial as both adults and larvae, feeding primarily on aphids. They also feed on mites, small insects, and insect eggs.  Many crops benefit from lady beetles. They are helpful for growers of vegetables, grain crops, legumes, strawberries, and tree crops; however any crop that is attacked by aphids will benefit from these beetles.

Female lady beetles may lay from 20 to more than 1,000 eggs over a one to three month period, commencingin spring or early summer.

New  medicines are tested on adults, but frequently prescribed to children  suffering from the ‘adult’ disorder. How do physicians know the proper  dose for sick children? How do they know if the drug will be effective?  The prevailing wisdom treated children as small adults. Physicians now  believe that this assumption may harm children, resulting in  overmedication, undermedication or adverse effects.

At a presentation at the AAAS annual meeting in Chicago,  I learned that physicians in the U.S. and the European Union are  studying the effects of adult medication on children, but have come up  against the issue of informed consent.

Human  subjects that agree to participate in a clinical study must “be given  the opportunity to choose what shall or shall not happen to them,”  according to the U.S. Department of Health and Human Services. Parents may give consent on behalf of their children.

Studies  of treatments for life-threatening situations, however, may not provide  time for informed consent. A child having a seizure, potentially  life-threatening, requires immediate treatment. The traditional drug is  diazepam; a newer drug of the same class is lorazepam, even though it’s  never been tested in a clinical trial on children.

A  new NIH study is comparing which seizure medication is more effective  in children, using the principle of exception from informed consent  (EFIC).

Under  EFIC, clinicians can treat a child with seizures using either  medication  without first  receiving consent from the parents. After the child is stabilized, the  parents can choose to opt out the child has still received treatment,  but no further data will be recorded as part of the study. Moreover,  parents may stipulate that in future seizure situations, their child  not participate in the study but receive conventional treatment.

The  guidlines for EFIC are strict: close supervision from the institution  where the study is performed, public disclosure, community  consultation, and the physicians must attempt to get informed consent  as soon as possible.

By - Joseph Letzelter

More elaborate and impressive mechanized water clocks were developed between 100 BCE and 500 CE by Greek and Roman horologists and astronomers. The added complexity was aimed at making the flow more constant by regulating the pressure, and at providing fancier displays of the passage of time. Some water clocks rang bells and gongs; others opened doors and windows to show little figures of people, or moved pointers, dials, and astrological models of the universe.

A Macedonian astronomer, Andronikos, supervised the construction of his Horologion, known today as the Tower of the Winds, in the Athens marketplace in the first half of the first century BCE. This octagonal structure showed scholars and shoppers both sundials and mechanical hour indicators. It featured a 24 hour mechanized clepsydra and indicators for the eight winds from which the tower got its name, and it displayed the seasons of the year and astrological dates and periods. The Romans also developed mechanized clepsydras, though their complexity accomplished little improvement over simpler methods for determining the passage of time.

In the Far East, mechanized astronomical/astrological clock making developed from 200 to 1300 CE. Third-century Chinese clepsydras drove various mechanisms that illustrated astronomical phenomena. One of the most elaborate clock towers was built by Su Sung and his associates in 1088 CE. Su Sung's mechanism incorporated a water-driven escapement invented about 725 CE. The Su Sung clock tower, over 30 feet tall, possessed a bronze power-driven armillary sphere for observations, an automatically rotating celestial globe, and five front panels with doors that permitted the viewing of changing manikins which rang bells or gongs, and held tablets indicating the hour or other special times of the day.

Croydon Airport (EGCR) was an airport in South London which straddled the boundary between what are now the London boroughs of Croydon and Sutton. Croydon was the first airport in the world to introduce air traffic control, in 1921. It was the main airport for London before it was replaced by Northolt Aerodrome, London Heathrow Airport and London Gatwick Airport.

It originated as two adjacent World War I airfields - Beddington Aerodrome, one of a number of small airfields around London, which had been created for protection against the Zeppelin raids in about May 1915, and Waddon Aerodrome of 1918, a test-flight aerodrome adjoining National Aircraft Factory No 1. Croydon Airport's Aerodrome Hotel is part of Croydon Vision 2020 regeneration plan.

At the end of World War I, the two airfields were combined into  London's official airport as the gateway for all international flights  to and from the capital. Croydon Aerodrome opened on 29 March 1920.

It stimulated a growth in regular scheduled flights carrying passengers, mail and freight, the first destinations being Paris, Amsterdam and Rotterdam. In 1923 Berlin flights were added. It was the operating base for Imperial Airways, remembered in the road name Imperial Way on the site today.

In the mid 1920s the airfield was extended, some adjacent roads such  as Plough Lane being closed to allow heavier airliners to land and  depart safely. A new complex of buildings was constructed adjoining Purley Way, including the first purpose-designed air terminal in the world, the Aerodrome Hotel and extensive hangars, at a cost of £267,000 (£11.5 million in today's prices). Although the first day of operation using the new building and layout  was 30 January, the official opening was not until 2 May 1928.

The Government of India has entrusted the work relating the ozone layer protection and implementation of Montreal Protocol to the Ministry. The Ministry has set up the Ozone Cell as a National Unit to look after and to render necessary services to implement the Protocol and its (ODS) phase-out programme in India. The Ministry has established an Empowered Steering Committee (ESC) chaired by the Secretary (E & F) which is supported by the Standing Committees. These Committees are responsible for the implementation of the Montreal Protocol provisions. Review of various policy and implementation options, project approvals and project monitoring.

India has met the following compliance dates as per the control schedule of the Montreal Protocol:-

• Freeze of CFC production and consumption in July, 1999 at 22588 ODP tons and 6681 ODP tons respectively.
• Freeze of Halon production and consumption on 1.1.2002
• Total phase-out of halon production and consumption in 2003.
• 50% reduction of CFC production and consumption in 2005 (production from 22588 MT to 11240 MT and consumption from 6681 MT to 1640 MT).
• 85% reduction of CTC production and consumption in 2005 (production from 11525 MT to 1508 MT and consumption from 11537 MT to 1493 MT).
• The Thirteenth International Day for the Preservation of the Ozone Layer was celebrated in Delhi on 16th September, 2007. The theme of this year’s International Ozone Day was 'Celebrating 20 Years of Progress'. Around 500 school children attended the function organized at Sri Satya Sai Auditorium. New Delhi. On this occasion poster, painting, skit competitions were organized among school children. Prizes for best 3 in each competition were given. Ozone Cell publication ‘Montreal Protocol India’s Success Story’, was released and distributed to the participants.

Handheld electronic cameras, in the sense of a device meant to be  carried and used like a handheld film camera, appeared in 1981 with the  demonstration of the Sony Mavica . This is not to be confused with the later  cameras by Sony that also bore the Mavica name. This was an analog  camera, in that it recorded pixel signals continuously, as videotape  machines did, without converting them to discrete levels; it recorded  television-like signals to a 2 x 2 inch "video floppy".  In essence it was a video movie camera that recorded single frames, 50  per disk in field mode and 25 per disk in frame mode. The image quality  was considered equal to that of then-current televisions.

Analog electronic cameras do not appear to have reached the market  until 1986 with the Canon RC-701. Canon demonstrated a prototype of  this model at the 1984 Summer Olympics, printing the images in the Yomiuri Shimbun,  a Japanese newspaper. In the United States, the first publication to  use these cameras for real reportage was USA Today, in its coverage of  World Series baseball. Several factors held back the widespread  adoption of analog cameras; the cost ,  poor image quality compared to film, and the lack of quality affordable  printers. Capturing and printing an image originally required access to  equipment such as a frame grabber, which was beyond the reach of the  average consumer. The "video floppy" disks later had several reader  devices available for viewing on a screen, but were never standardized  as a computer drive.

The early adopters tended to be in the news media, where the cost  was negated by the utility and the ability to transmit images by  telephone lines. The poor image quality was offset by the low  resolution of newspaper graphics. This capability to transmit images  without a satellite link was useful during the Tiananmen Square protests of 1989 and the first Gulf War in 1991.

US government agencies also took a strong interest in the still  video concept, notably the US Navy for use as a real time air-to-sea  surveillance system.

The first analog camera marketed to consumers may have been the  Canon RC-250 Xapshot in 1988. A notable analog camera produced the same  year was the Nikon QV-1000C,  designed as a press camera and not offered for sale to general users,  which sold only a few hundred units. It recorded images in greyscale, and the quality in newspaper print was equal to film cameras. In appearance it closely resembled a modern digital single-lens reflex camera. Images were stored on video floppy disks.