Sunday, September 23, 2007
Traffic Light
A traffic light or traffic signal is a signalling device positioned at a road junction or pedestrian crossing to indicate when it is safe to drive, ride or walk, using a universal color code.Traffic lights for usual vehicles or pedestrians always have two main lights, a red one that means stop and a green one that means go. Generally, the red light contains some orange in its hue, and the green light contains some blue, to provide some support for people with red-green color blindness. In most countries there is also a yellow (or amber) light, which when on and not flashing means stop if able to do so securely. In some systems, a flashing amber means that a motorist may go in advance with care if the road is clear, giving way to pedestrians and to other road vehicles that may have precedence. A flashing red effectively means the same as a regular stop sign. There may be additional lights (usually a green arrow or "filter") to allow turns (called a lead light in the U.S., because it is usually leading the main green light).
Thursday, September 13, 2007
Goshawk
The Goshawk is an average large bird of quarry in the family Accipitridae which also includes many other diurnal raptors such as eagles, buzzards and harriers.
It is an extensive species all through the moderate parts of the northern hemisphere. In North America it is named as the Northern Goshawk. It is typically inhabitant, but birds from colder regions of north Asia and Canada journey south for the winter.
Goshawk in flight this species nests in trees, building a new nest each year. It hunts birds and mammals in woodland, relying on revelation as it flies from a perch or hedge-hops to catch its quarry ignorant. Animals as large as hares and Pheasant are taken. Its call is a ferocious screech. Many older goshawks reject to attack hares, if it was earlier seriously kicked by a hare which it tried to catch.
This bird is a raptor with short large wings and a long tail, both adaptations to maneuvering through trees. The male is blue-grey above and banned grey below, 49-56 cm long with a 93-105 cm wingspan. The much larger female is 58-64 cm long with a 108-127 cm wingspan, slate grey above grey below. The youthful is brown above and barred brown below. The flight is a characteristic "slow flap – slow flap – straight glide".
In Eurasia, the male is confusable with a female Sparrow hawk, but is superior, much bulkier and has moderately longer wings. In spring, he has an impressive roller-coaster display, and this is the best time to see this enigmatic forest bird.
It is an extensive species all through the moderate parts of the northern hemisphere. In North America it is named as the Northern Goshawk. It is typically inhabitant, but birds from colder regions of north Asia and Canada journey south for the winter.
Goshawk in flight this species nests in trees, building a new nest each year. It hunts birds and mammals in woodland, relying on revelation as it flies from a perch or hedge-hops to catch its quarry ignorant. Animals as large as hares and Pheasant are taken. Its call is a ferocious screech. Many older goshawks reject to attack hares, if it was earlier seriously kicked by a hare which it tried to catch.
This bird is a raptor with short large wings and a long tail, both adaptations to maneuvering through trees. The male is blue-grey above and banned grey below, 49-56 cm long with a 93-105 cm wingspan. The much larger female is 58-64 cm long with a 108-127 cm wingspan, slate grey above grey below. The youthful is brown above and barred brown below. The flight is a characteristic "slow flap – slow flap – straight glide".
In Eurasia, the male is confusable with a female Sparrow hawk, but is superior, much bulkier and has moderately longer wings. In spring, he has an impressive roller-coaster display, and this is the best time to see this enigmatic forest bird.
Goshawk
The Goshawk is an average large bird of quarry in the family Accipitridae which also includes many other diurnal raptors such as eagles, buzzards and harriers.
It is an extensive species all through the moderate parts of the northern hemisphere. In North America it is named as the Northern Goshawk. It is typically inhabitant, but birds from colder regions of north Asia and Canada journey south for the winter.
Goshawk in flight this species nests in trees, building a new nest each year. It hunts birds and mammals in woodland, relying on revelation as it flies from a perch or hedge-hops to catch its quarry ignorant. Animals as large as hares and Pheasant are taken. Its call is a ferocious screech. Many older goshawks reject to attack hares, if it was earlier seriously kicked by a hare which it tried to catch.
This bird is a raptor with short large wings and a long tail, both adaptations to maneuvering through trees. The male is blue-grey above and banned grey below, 49-56 cm long with a 93-105 cm wingspan. The much larger female is 58-64 cm long with a 108-127 cm wingspan, slate grey above grey below. The youthful is brown above and barred brown below. The flight is a characteristic "slow flap – slow flap – straight glide".
In Eurasia, the male is confusable with a female Sparrow hawk, but is superior, much bulkier and has moderately longer wings. In spring, he has an impressive roller-coaster display, and this is the best time to see this enigmatic forest bird.
It is an extensive species all through the moderate parts of the northern hemisphere. In North America it is named as the Northern Goshawk. It is typically inhabitant, but birds from colder regions of north Asia and Canada journey south for the winter.
Goshawk in flight this species nests in trees, building a new nest each year. It hunts birds and mammals in woodland, relying on revelation as it flies from a perch or hedge-hops to catch its quarry ignorant. Animals as large as hares and Pheasant are taken. Its call is a ferocious screech. Many older goshawks reject to attack hares, if it was earlier seriously kicked by a hare which it tried to catch.
This bird is a raptor with short large wings and a long tail, both adaptations to maneuvering through trees. The male is blue-grey above and banned grey below, 49-56 cm long with a 93-105 cm wingspan. The much larger female is 58-64 cm long with a 108-127 cm wingspan, slate grey above grey below. The youthful is brown above and barred brown below. The flight is a characteristic "slow flap – slow flap – straight glide".
In Eurasia, the male is confusable with a female Sparrow hawk, but is superior, much bulkier and has moderately longer wings. In spring, he has an impressive roller-coaster display, and this is the best time to see this enigmatic forest bird.
Wednesday, September 05, 2007
Tumor
Tumor or tumour is an irregular growth or mass of tissue. A tumor can be either malignant or benign. Almost all tumors are examples of neoplasia, although certain developmental malformations or inflammatory masses may occasionally be referred to as tumors.
Neoplastic tumors are caused by mutations in DNA of cells, which interfere with a cell's capability to regulate and limit cell division. An accumulation of mutations is needed for a tumor to emerge. Mutations that activate oncogenes or repress tumor suppressor genes can eventually lead to tumors. Cells have mechanisms that repair DNA and other mechanisms that cause the cell to destroy itself by apoptosis if DNA damage gets too severe. Mutations that repress the genes for these mechanisms can also ultimately guide to cancer. A mutation in one oncogene or one tumor repressor gene is usually not enough for a tumor to occur. A combination of a number of mutations is essential.
Neoplastic tumors are caused by mutations in DNA of cells, which interfere with a cell's capability to regulate and limit cell division. An accumulation of mutations is needed for a tumor to emerge. Mutations that activate oncogenes or repress tumor suppressor genes can eventually lead to tumors. Cells have mechanisms that repair DNA and other mechanisms that cause the cell to destroy itself by apoptosis if DNA damage gets too severe. Mutations that repress the genes for these mechanisms can also ultimately guide to cancer. A mutation in one oncogene or one tumor repressor gene is usually not enough for a tumor to occur. A combination of a number of mutations is essential.
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