Science and Medicine

Male Fish Go from ‘Zero to 60’ to Mate

A dominant male cichlid looms from the dark waters of his territory, ready to fend off subordinate males who might try to cross the boundary. (Credit: Todd Anderson)

Subordinate cichlid fish have an impressive ability to rise to the procreative occasion with stunning speed if the alpha male—usually the only one to reproduce—abdicates.

In cichlid society, the second-string male fish hang around the fringes, keeping their reproductive systems idling to the point they can practically pass for females. But when the dominant male disappears, the beta boys have turned out to be unexpectedly fast on the spawn.

“It is amazing how quickly they can recover from being down and out,” said Russ Fernald, professor of biology at Stanford University.

A newly self-appointed alpha begins “acting alpha” within a few minutes of the disappearance of the old top dog. It can spawn successfully within a few hours and will have its sperm in top reproductive condition in less than a day.

All this from a creature that for weeks has endured drastically lowered hormone levels, severely shrunken testes, and a noticeable (and perhaps understandable) pallor compared to the brightly colored alphas that have been knocking them around and monopolizing all the females.

Read more: Male Fish Go from ‘Zero to 60’ to Mate

No comments
 

Obesity Up, Life Expectancy Down

As the population becomes heavier faster, people are living more of their lives with risks associated with obesity, such as Type II diabetes.

The obesity epidemic in the United States may end the nearly century-long steady climb in life expectancy, according to new research.

A study published in the journal Health Affairs says in order to accurately forecast future lifespans and to map out health policy decisions, it is essential to consider the health of the younger generation.

“Our analysis shows that health declines and reduced life expectancies will occur without aggressive public health action,” says Yang Yang, associate professor of sociology at the University of North Carolina at Chapel Hill.

Forecasting now looks at death rates for each age at a given year or years to predict future death rates.

“Traditional forecasting assumes that when today’s children reach the age of 70, they will have the same mortality rate as people who are 70 today,” Yang said.

The researchers used the traditional forecasting method to predict cardiovascular disease death rates among men after the year 2000. Then they sought the same information using their new model, which also accounted for the health status of younger populations.

Their method was found to be more accurate, correctly predicting an increase in cardiovascular death rates for men between the ages of 25 and 29. This may be because younger men have been more affected by the obesity epidemic than their predecessors.

Read more: Obesity Up, Life Expectancy Down

No comments
   

Binge Drinkers Crave Liquid Courage

Participants rated the upsides to drinking as more positive and likely to happen in the future, a finding the researchers call “rose-colored beer goggles.”

The added social benefits of chattiness and charisma can trump the negative effects of too much alcohol for some binge drinkers.

The findings, published online in the journal Psychology of Addictive Behaviors, offer a new direction for intervention programs, which tend to focus on avoiding alcohol’s negative results rather than considering its rewards.

“This study suggests why some people can experience a lot of bad consequences of drinking but not change their behavior,” said Kevin King, assistant professor of psychology at the University of Washington “People think, ‘It’s not going to happen to me’ or ‘I’ll never drink that much again.’ They do not seem to associate their own heavy drinking with negative consequences.”

For the study, nearly 500 college students completed an online survey measuring their drinking habits during the previous year that assessed how often the participants had experienced 35 different negative consequences of drinking, including blackouts, fights, hangovers, missed classes and work, and lost or stolen belongings.

Read more: Binge Drinkers Crave Liquid Courage

No comments
   

Page 27 of 52