Archive for May 28th, 2012
On June 5th-6th the planet Venus will pass across the face of the sun. This will be just the seventh occasion on which this rare spectacle has been observed. The first person to witness such an event was a young astronomer called Jeremiah Horrocks, living in an obscure British hamlet, who correctly forecast that it would occur on December 4, 1639 (November 24, 1639 under the Julian calendar then in use in England).
… after this year's event, the next transit of Venus occures December 11, 2117.
& today in history:
Memorial Day is a U.S. federal holiday observed on the last Monday of May. Formerly known as Decoration Day, it commemorates those who died while in military service.
First enacted by formerly enslaved African-Americans to honor Union soldiers of the Civil War – it was extended after World War I to honor all Americans who made the greatest sacrifice, regardless of conflict.
Newfound details of the immune system suggest a role for never-before-considered drug classes in the treatment of allergic and autoimmune diseases, according to a University of Alabama at Birmingham study published online May 27 in Nature Immunology.
The results advance the current understanding of the way the body's initial, vague reaction to any invading organism expands into a precise and massive counterattack. That expansion starts when a dendritic cell "swallows" a piece of any invader encountered, ferries it to the nearest lymph node and presents it there for notice by lymphocytes, the workhorse cells of the immune system.
According to the current model, dendritic cells first must encounter T lymphocytes in the paracortex, or T cell zone, within the node. Only there will the interaction enable lymphocytes to expand into an army of clones primed to attack the invader.
To the research team's great surprise, the data showed that, although immune response works this way during viral flu infections, it is not always the case. When the body is infested with parasitic worms, for instance, dendritic cells link with T cells near B lymphocytes, under the control of B cell-related signals and outside the T cell zone.
"Considering that diseases from asthma to lupus can occur because the system mistakenly ramps up the same types of T cell responses it normally uses against worms, our finding that B lymphocytes control the T cell/dendritic cell interactions that trigger such responses has important, practical implications," said Frances Lund, Ph.D., chair of the UAB School of Medicine's Department of Microbiology and corresponding author. "The field now has cause to look at several experimental and existing drugs [along with other innovative treatments such as UVA1 phototherapy] known to interrupt B cell signals as potential treatments for diseases driven by T cells."
As the number of species at risk of extinction soars, zoos are increasingly being called upon to rescue and sustain animals, and not just for marquee breeds like pandas and rhinos but also for all manner of mammals, frogs, birds and insects whose populations are suddenly crashing.
To conserve animals effectively, however, zoo officials have concluded that they must winnow species in their care and devote more resources to a chosen few. The result is that zookeepers, usually animal lovers to the core, are increasingly being pressed into making cold calculations about which animals are the most crucial to save. Some days, the burden feels less like Noah building an ark and more like Schindler making a list.