Foto 25 Jul 2 notas fernand0:

Infographic: 25 years of the firewall
Vídeo 24 Jul 124 936 notas

(Fuente: youtube.com)

Foto 24 Jul 4 notas

(Fuente: tevasacagar)

Vídeo 23 Jul 597 notas

amnhnyc:

Happy birthday to Vera Rubin! The pioneering astronomer turns 86 today. 

Learn about her career and contribution to the discovery of dark matter in this profile, and in our Dark Matter explainer video

Foto 23 Jul 2 notas ozfromaustin:

❝Swift as a deer. Qu http://bit.ly/1p7RXdR

ozfromaustin:

❝Swift as a deer. Qu http://bit.ly/1p7RXdR

Foto 23 Jul 2 notas ozfromaustin:

elf ranger with kitt http://bit.ly/1A326B3

ozfromaustin:

elf ranger with kitt http://bit.ly/1A326B3

Vídeo 23 Jul 30 notas

astroperlas:

La superficie de Venus vista por las Venera 9 y 10 (Ted Stryk).

Vía.

Vídeo 23 Jul 24 notas

sciencesourceimages:

It All Stems From Stems.

 Xylem and Phloem tissues are found together in vascular bundles in the stems of plants and trees. The xylem transports water and soluble mineral nutrients from the roots throughout the plant. It is also used to replace water lost during transpiration and photosynthesis. Xylem sap consists mainly of water and inorganic ions, although it can contain a number of organic chemicals as well. The transport taking place in the xylem is passive. Surface tension caused by the evaporation of water to the atmosphere pulls more water and minerals up from the roots like a straw.

Click to see more amazing light micrographs of Plant Stems

Unlike xylem, which is composed mainly dead cells, the phloem is composed of still living cells that transport sap. The sap is a water-based solution, but rich in sugars made by the photosynthetic areas. These sugars are transported to non-photosynthetic parts of the plant, such as the roots, or into storage structures, such as tubers or bulbs. During the plant’s growth period, usually during the spring, storage organs such as the roots are sugar sources, and the plant’s many growing areas are sugar sinks. The movement in phloem is multi-directional, whereas, in xylem cells, it is uni-directional (upward).

All images above © Dr. Keith Wheeler / Science Source 

Foto 23 Jul 2 notas todoestadicho:

Obi Wan http://ift.tt/1uM96gu
Foto 23 Jul 2 notas fotoblog4u:

lisahewitt
via PhotoBlog.
Foto 23 Jul 1 137 notas bluepueblo:

Haifoss Waterfall, Iceland
photo via holly

bluepueblo:

Haifoss Waterfall, Iceland

photo via holly

Foto 22 Jul 2 notas
Foto 22 Jul 5 notas astroperlas:

Cape Tribulation visto por Opportunity (NASA/JPL).

astroperlas:

Cape Tribulation visto por Opportunity (NASA/JPL).

Cita 22 Jul 311 notas
I think most people do not imagine how things can change. In Detroit, there are community gardens that are only an indication that the country is coming back to the city. And that is something that actually is necessary to stop the real imminent danger of the extermination of our planet. When I came to Detroit, if you threw a stone up in the air it would hit an autoworker on its way down. A few years after that, if you threw a stone in the air it’d hit an abandoned house or a vacant lot on its way down. And most people saw those vacant lots as blight. But meanwhile during World War II, blacks had moved from the South to the North. And they saw these vacant lots as places where you could grow food for the community. And so urban agriculture was born. And that came about not because anyone planned it, but because the vacant lots, produced by abandonment, created the opportunity for bringing the country back into the city, and actually saving the planet in the process.
Foto 22 Jul 28 notas astroperlas:

Las islas Canarias vistas desde la ISS por Oleg Artemyev (Roscosmos).

astroperlas:

Las islas Canarias vistas desde la ISS por Oleg Artemyev (Roscosmos).


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