scientific american - 1993 06 - tuning in the radio signals of ancient galaxies

... both then at the University of Edinburgh, ob- served radio galaxies from the 3C cata- logue in the infrared using the U.K. In- frared Telescope in Hawaii. They then constructed a graph of redshift ... consid- ered to be a radio galaxy. Another likely in uence on the ob- served properties of radio- emitting gal- axies is the nature of the local environ- ment...

Ngày tải lên: 12/05/2014, 14:49

... regional significance in the past 3 years; type A Iran-05 (BAR-08 strain) in 2008, the type O Panasia-2 epidemic in 201 0-1 1, and the Asia-1 epidemic of 201 1-1 2, all of which involved east to west ... knowledge of the influence of each of the factors and implement measures from the start of virus production up to the packaging of the produced vacci...

Ngày tải lên: 18/03/2014, 00:20

... values of its variables. Checking is simply a matter of mak- ing sure the calculated value of the poly- nomial at any point matches that as- serted in the proof. Only a small num- ber of points ... received her fatherÕs grudg- ing consent, Levi-Montalcini studied for the entrance examination and then en- rolled in the Turin School of Medicine at the age of 21. Draw...

Ngày tải lên: 12/05/2014, 14:48

... tidying up some of the loose ends in the in ationÓ ac- count of the origins of the universe. In- ßation theorists suggest that the uni- verse began as a highly curved core of matter. At some point, ... alone. Copyright 1993 Scientific American, Inc. 40 SCIENTIFIC AMERICAN February 1993 ests of the developed and the develop- ing worlds. H uman actions bri...

Ngày tải lên: 12/05/2014, 14:48

... ferrying the virus across the blood-brain barrier. Another main- tains the blood-brain barrier is some- how disrupted, permitting the entry of viral particles or infected cells. Once there, the virus ... basis of what she actually sees. I call this the seeing-is-believing principle. T he true signiÞcance of the see- ing-is-believing principle was not revealed to me until 1...

Ngày tải lên: 12/05/2014, 14:49

... stable, the high birth rates of the baby boom postponed the aging of the population by widen- ing the base of the age structure again. As the baby boomers grow older, how- ever, the average age of the ... sense the state of atoms after they have passed through the cavity. The red laser beam traces the line of the in- frared laser used to excite the...

Ngày tải lên: 12/05/2014, 14:49

... villainÕs role in other autoimmune diseases: in insulin-dependent diabetes, T lymphocytes destroy insulin-produc- ing cells in the pancreas, and in multiple sclerosis, they direct their fury against the ... During these interac- tions, the B cell can also in uence the activity of the T cell. B CELL T CELL LYMPHOKINES Copyright 1993 Scientific American, Inc. uterus...

Ngày tải lên: 12/05/2014, 14:50

... and the origin of new species. The recognition of large igneous prov- inces has forced geophysicists to re- think their notions regarding the struc- ture of the earthÕs interior. The theory of plate ... in a chain, the sequence could be determined in the following way. After labeling the chains, they could be broken down into individ- ual amino acids, indicating, s...

Ngày tải lên: 12/05/2014, 14:50

... to suspend the trading rights of countries that sanc- tion the use of purse-seine nets in tuna Þshing and of leg-hold traps in trap- ping. Such punishments seem an in- appropriate use of state ... growth), they do so at the expense of labor in the high-wage coun- tries. They thereby increase income in- equality there. Most citizens are wage earners. In the U.S....

Ngày tải lên: 12/05/2014, 14:50

... conditions. At the be- ginning of the race, the runners line up at the startÑthat is, they are well local- ized. Each one runs in one of the quan- tized Bohr orbits. During the initial laps, the runners ... initial lu- nar-landing attempt had slipped into the second half of 1969. The U.S. was well aware of the Soviet decision to proceed with the N-1 but for sev...

Ngày tải lên: 12/05/2014, 14:56