Weight-loss guidelines have long counselled dieters that kilos shed too quickly are likelier to creep back than those lost at a slower pace.

But an Australian study, published on Wednesday, says this is wrong.

U.S. President Barack Obama on Wednesday pledged a "much more aggressive" response at home to the Ebola threat, and insisted that the risk of a serious outbreak on U.S. soil was low.

After a crisis meeting with top aides at the White House, Obama underlined the importance of helping African countries stem the spread of the virus, calling such aid "an investment in our own public health."

A Liberian Ebola patient was left in an open area of a Dallas emergency room for hours, and the nurses treating him worked for days without proper protective gear and faced constantly changing protocols, according to a statement released late Tuesday by the largest U.S. nurses' union.

Nurses were forced to use medical tape to secure openings in their flimsy garments, worried that their necks and heads were exposed as they cared for a patient with explosive diarrhea and projectile vomiting, said Deborah Burger of National Nurses United.

Nurses at the Texas hospital where a Liberian Ebola patient died last week complain they were given few rules and little guidance on how to treat the severely ill man, contrary to assertions by US health authorities.

The head of the US Centers for Disease Control and Prevention (CDC), Thomas Frieden, said earlier this week that a "breach in protocol" by health workers led to a nurse becoming infected with the potentially fatal virus.

Embryonic stem cells transplanted into 18 patients with deteriorating eyesight restored some vision in more than half the volunteers, the longest study into the fledgling technology reported Tuesday.

Stem cells derived from embryos "could provide a potentially safe new source of cells for the treatment of various unmet medical disorders requiring tissue repair or replacement," its authors said.

The world is falling behind in a desperate race stop the deadly Ebola outbreak, a top UN official warned on Tuesday amid dire predictions that thousands of new infections are possible before year's end.

"Ebola got a head start on us," said Anthony Banbury, head of the UN Mission for Ebola Emergency Response.

Top athletes are often dogged by decaying teeth and gum disease, a performance-sapping problem in which sports drinks, high-carb diets and training regimes may play a part, specialists said Monday.

Experts from Britain and North America reviewed 39 published studies into the oral health of elite or professional sportsmen and women.

A Louisiana firm said Monday it will not accept medical waste from the late Ebola patient in Texas, even though it acknowledged the refuse is safe.

Liberian Thomas Eric Duncan was the first person diagnosed with Ebola outside Africa. Duncan was hospitalized September 28 and died of Ebola on Wednesday in Dallas.

The U.S. and U.N. leaders on Monday called for "more robust" international efforts to tackle Ebola, after medics in Liberia demanded danger money to treat patients in what officials termed the worst health crisis of modern times.

The call from U.S. President Barack Obama and U.N. Secretary General Ban Ki-moon came as doctors and nurses in Liberia, one of the worst-hit countries, went on strike to demand higher pay to care for Ebola patients there.

Their legacy already established in politics, Mitt Romney and his wife, Ann, are working to leave a lasting mark on neuroscience.

Boston's Brigham and Women's Hospital on Tuesday will announce the launch of the Ann Romney Center for Neurologic Diseases, a venture funded by the Romneys and their expansive political network that will assemble scores of the world's most accomplished doctors and scientists to collaborate in battling five neurological diseases that have no cure: multiple sclerosis, Alzheimer's, ALS, Parkinson's and brain tumors.