Sunday, January 11, 2009

At the Zoo

At the Zoo

This photo released by the Lincoln Children's Zoo, shows Milla, a Matschie's tree kangaroo, on Tuesday, Jan. 6, 2009 in Lincoln, Neb. The Lincoln Children's Zoo is celebrating its first set of Matschie's tree kangaroo twins and an official who tracks numbers of the extremely rare species says it's the first documented case in North America among records that go back to the 1970s. The twins born last month to Milla and her mate Noru, brought in from the Toronto Zoo, make up half of the four documented Matschie's tree kangaroo births in 2008. The twins are in her pouch.
(AP Photo/ Lincoln Children's Zoo)

Flamingos are counted during the annual animal count at London Zoo in London, Thursday, Jan. 8, 2009. A complete head count of every animal, insect and bird living at the zoo is to take place, with more than 650 different species to tally up.
(AP Photo/Kirsty Wigglesworth)

Female Sumatran Tiger Jumilah licks on a blood infused iceblock as she attempts to cool down at Sydney's Taronga Zoo, Tuesday, Jan. 6, 2009. Animals at Sydney's zoo were given large homemade ice blocks filled with fruit to help stay cool as temperatures were expected to hit 41C (106F). The ambulance service issued a warning for the elderly and children to stay out of the heat and drink plenty of water as as a heatwave hits the state.
(AP Photo/Mark Baker)

Sunday, November 16, 2008

Safety data for tannic acid

Glossary of terms on this data sheet.

The information on this web page is provided to help you to work safely, but it is intended to be an overview of hazards, not a replacement for a full Material Safety Data Sheet (MSDS). MSDS forms can be downloaded from the web sites of many chemical suppliers.


    Synonyms: gallotannic acid, gallotannin, glycerite, tannin
    Molecular formula: C76H52O46
    CAS No: 1401-55-4
    EC No: 215-753-2

Physical data

    Appearance: white or light yellow powder
    Melting point: 210 C
    Boiling point:
    Vapour density:
    Vapour pressure:
    Density (g cm-3):
    Flash point: 199 C (closed cup)
    Explosion limits:
    Autoignition temperature:
    Water solubility:


    Stable. Incompatible with metallic salts, strong oxidizing agents, iron and other heavy metals.


    Not hazardous according to Directive 67/548/EEC.

    Toxicity data
    (The meaning of any abbreviations which appear in this section is given here.)
    ORL-RAT LD50 2260 mg kg-1
    IPR-MUS LD50 120 mg kg-1
    ORL-RBT LD50 5000 mg kg-1

    Risk phrases
    (The meaning of any risk phrases which appear in this section is given here.)

Transport information

    Non-hazardous for air, sea and road freight.

Personal protection

    Minimize contact.

    Safety phrases
    (The meaning of any safety phrases which appear in this section is given here.)


If I Were a Boy

Ang astig ng song na 'to no?

If I were a boy

Even just for a day
I’d roll outta bed in the morning
And throw on what I wanted then go
Drink beer with the guys
And chase after girls
I’d kick it with who I wanted
And I’d never get confronted for it.
Cause they’d stick up for me.


If I were a boy
I think I could understand
How it feels to love a girl
I swear I’d be a better man.
I’d listen to her
Cause I know how it hurts
When you lose the one you wanted
Cause he’s taken you for granted
And everything you had got destroyed

If I were a boy
I could turn off my phone
Tell everyone it’s broken
So they’d think that I was sleepin’ alone
I’d put myself first
And make the rules as I go
Cause I know that she’d be faithful
Waitin’ for me to come home (to come home)


It’s a little too late for you to come back
Say its just a mistake
Think I’d forgive you like that
If you thought I would wait for you
You thought wrong


But you’re just a boy
You don’t understand
Yeah you don’t understand
How it feels to love a girl someday
You wish you were a better man
You don’t listen to her
You don’t care how it hurts
Until you lose the one you wanted
Cause you’ve taken her for granted
And everything you have got destroyed
But you’re just a boy

Thursday, November 6, 2008

Geneva drive

The Geneva drive or Maltese cross is a mechanism that translates a continuous rotation into an intermittent rotary motion. It is an intermittent gear where the drive wheel has a pin that reaches into a slot of the driven wheel and thereby advances it by one step. The drive wheel also has a raised circular blocking disc that locks the driven wheel in position between steps.

Besides the external Geneva drive shown in the diagram above, there is also an internal Geneva drive. The external form is the more common, as it can be built smaller and can withstand higher mechanical stresses. The axis of the drive wheel of the internal Geneva drive can have a bearing only on one side. The angle by which the drive wheel has to rotate to effect one step rotation of the driven wheel is always smaller than 180° in an external Geneva drive and always greater than 180° in an internal one, where the switch time is therefore greater than the time the driven wheel stands still.



An autostereogram is a single-image stereogram (SIS), designed to create the visual illusion of a three-dimensional (3D) scene from a two-dimensional image in the human brain. In order to perceive 3D shapes in these autostereograms, the brain must overcome the normally automatic coordination between focusing and vergence.

When a series of autostereograms are shown one after another, in the same way moving pictures are shown, the brain perceives an animated autostereogram. If all autostereograms in the animation are produced using the same background pattern, it is often possible to see faint outlines of parts of the moving 3D object in the 2D autostereogram image without wall-eyed viewing; the constantly shifting pixels of the moving object can be clearly distinguished from the static background plane. To eliminate this side effect, animated autostereograms often use shifting background in order to disguise the moving parts.


Wednesday, November 5, 2008

Animal Camouflage

Instead of webs, the goldenrod crab spider, Misumena vatia, uses camouflage to ambush its prey, slowly changing color to match the flower on which it’s perched. It does this by moving yellow pigment closer to or farther from its outermost layer of cells. The species is most often found among yellow and white blooms, but it can morph into a green or bluish hue when necessary, or even take on reddish spots or stripes. Thus disguised, the arachnid waits frozen, its front legs poised to snap closed in a deadly embrace on hapless insects that come into range. The spider’s venomous bite can take down bugs as large as butterflies and bumblebees.

Here, a speckled sanddab nestles into the ocean floor, its skin mottled to mimic the pebbly background. A member of the flounder family, Citharichthys stigmaeus can change its topside appearance with cells called chromatophores. Pigment granules in these cells migrate closer to the cell surface to create patterns on its brown skin. This camouflage hides the fish from predators off the Pacific coast where it’s found and enables it to surprise its prey—smaller bony fishes, shrimp and worms.

Its unique black-and-white coloring helps the many-spotted tiger moth both stand out and blend in. Native to the western U.S., this moth may feed on mildly toxic plants like milkweed, taking the plant poisons into its own body as a natural defense against predators. Most often, the species’ white body advertises “I taste bad” to birds who spot it flying in the air, says biologist Rebecca Simmons of the University of North Dakota. But when it comes to rest against a dappled background, like the one pictured here, Hypercompe permaculata’s coloring also breaks up the outline of its body, allowing it to blend in and hide from birds that might not heed its white warning.

The round object in the center-right of this photo is no rock—it’s a rock ptarmigan hiding motionless among the stones and moss of the Alaskan tundra. (Look for its beak to spot its head.) In the winter snow, Lagopus muta exchanges its brown feathers for white, maintaining year-round protection from its main predator, the gyrfalcon. In the spring, males retain their white feathers after the snow disappears, advertising themselves to potential mates. Once they’ve mated, and before the brown feathers grow back, males roll around in the dirt, creating a makeshift camouflage, which is eventually replaced by a summer disguise like the one on the female shown here.

Huddled together against a rocky Canadian cliff face, a typical nesting site, these two gyrfalcon chicks blend into the marbled stone. Adult Falco rusticolus patrol the air in arctic regions, feeding on their tundra neighbors, the well-hidden ptarmigan and other smaller birds. Gyrfalcons are clad in inconspicuous gray, white and brown feathers, with a light underside.

Known for its distinctive high-pitched call, the spring peeper frog’s coloring ranges from grayish to reddish brown, a fitting adaptation to the leaves and dead grass of its wooded habitat in the eastern and midwestern United States. Darker markings, including the cross on its back, help break up Pseudacris crucifer’s silhouette against its surroundings. To add to the illusion, the tiny frog can also adjust its hue slightly within the gray-brown range to better match its environment.


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